3D Numerical Simulation on the Rockslide Generated Tsunamis

NASA Astrophysics Data System (ADS)

Chuang, M.; Wu, T.; Wang, C.; Chu, C.

2013-12-01

The rockslide generated tsunami is one of the most devastating nature hazards. However, the involvement of the moving obstacle and dynamic free-surface movement makes the numerical simulation a difficult task. To describe both the fluid motion and solid movement at the same time, we newly developed a two-way fully-coupled moving solid algorithm with 3D LES turbulent model. The free-surface movement is tracked by volume of fluid (VOF) method. The two-step projection method is adopted to solve the Navier-Stokes type government equations. In the new moving solid algorithm, a fictitious body force is implicitly prescribed in MAC correction step to make the cell-center velocity satisfied with the obstacle velocity. We called this method the implicit velocity method (IVM). Because no extra terms are added to the pressure Poission correction, the pressure field of the fluid part is stable, which is the key of the two-way fluid-solid coupling. Because no real solid material is presented in the IVM, the time marching step is not restricted to the smallest effective grid size. Also, because the fictitious force is implicitly added to the correction step, the resulting velocity is accurate and fully coupled with the resulting pressure field. We validated the IVM by simulating a floating box moving up and down on the free-surface. We presented the time-history obstacle trajectory and compared it with the experimental data. Very accurate result can be seen in terms of the oscillating amplitude and the period (Fig. 1). We also presented the free-surface comparison with the high-speed snapshots. At the end, the IVM was used to study the rock-slide generated tsunamis (Liu et al., 2005). Good validations on the slide trajectory and the free-surface movement will be presented in the full paper. From the simulation results (Fig. 2), we observed that the rockslide generated waves are manly caused by the rebounding waves from two sides of the sliding rock after the water is dragging down by the solid downward motion. We also found that the turbulence has minor effect to the main flow field. The rock size, rock density, and the steepness of the slope were analyzed to understand their effects to the maximum runup height. The detailed algorithm of IVM, the validation, the simulation and analysis of rockslide tsunami will be presented in the full paper. Figure 1. Time-history trajectory of obstacle for the floating obstacle simulation. Figure 2. Snapshots of the free-surface elevation with streamlines for the rockslide tsunami simulation.

A short history of tsunami research and countermeasures in Japan.

PubMed

Shuto, Nobuo; Fujima, Koji

2009-01-01

The tsunami science and engineering began in Japan, the country the most frequently hit by local and distant tsunamis. The gate to the tsunami science was opened in 1896 by a giant local tsunami of the highest run-up height of 38 m that claimed 22,000 lives. The crucial key was a tide record to conclude that this tsunami was generated by a "tsunami earthquake". In 1933, the same area was hit again by another giant tsunami. A total system of tsunami disaster mitigation including 10 "hard" and "soft" countermeasures was proposed. Relocation of dwelling houses to high ground was the major countermeasures. The tsunami forecasting began in 1941. In 1960, the Chilean Tsunami damaged the whole Japanese Pacific coast. The height of this tsunami was 5-6 m at most. The countermeasures were the construction of structures including the tsunami breakwater which was the first one in the world. Since the late 1970s, tsunami numerical simulation was developed in Japan and refined to become the UNESCO standard scheme that was transformed to 22 different countries. In 1983, photos and videos of a tsunami in the Japan Sea revealed many faces of tsunami such as soliton fission and edge bores. The 1993 tsunami devastated a town protected by seawalls 4.5 m high. This experience introduced again the idea of comprehensive countermeasures, consisted of defense structure, tsunami-resistant town development and evacuation based on warning.

“Hello, HELLO! Anyone there? - on the need to assess the tsunami risk to global submarine telecommunications infrastructure

NASA Astrophysics Data System (ADS)

Dominey-Howes, D.; Goff, J. R.

2009-12-01

National economies are increasingly dependent on the global telecommunications system - and in particular, its submarine cable infrastructure. Submarine cable traffic represents about 30% of global GDP so the cost of losing, or even simply slowing, communications traffic is high. Many natural hazards are capable of damaging and destroying this infrastructure but tsunamis are the most significant threat, particularly in waters >1000 m deep. Submarine cables and their shore-based infrastructure (the anchor points), are at risk from direct and indirect tsunami-related effects. During the 2004 Indian Ocean Tsunami in India and Indonesia, cables were broken (direct effect) as the tsunami eroded supporting sediments, and were further damaged by floating/submerged objects and intense nearshore currents. Shore-based infrastructure was also directly damaged in India, Indonesia, and the Maldives. The 1929 Grand Banks earthquake generated a submarine landslide and tsunami off Newfoundland which broke 12 submarine telegraph cables. In 2006, an earthquake in Taiwan generated submarine landslides and a tsunami. These landslides caused one of the largest disruptions of modern telecommunications history when nine cables in the Strait of Luzon were broken disabling vital connections between SE Asia and the rest of the world. Although electronic traffic in and out of Australia was slowed, it did not cease because >70% of our traffic is routed via cables that pass through Hawaii. This is extremely significant because Hawaii is an internationally recognised bottleneck or “choke point” in the global telecommunications network. The fact that Hawaii is a choke point is important because it is regularly affected by numerous large magnitude natural hazards. Any damage to the submarine telecommunications infrastructure routed through Hawaii could result in significant impacts on the electronic flow of data and voice traffic, negatively affecting dependent economies such as Australia. Other choke points exist globally, many in high hazards regions. We propose that proper risk assessments be undertaken at all bottlenecks in the global telecommunications system affected by natural hazards (such as tsunami). We use Hawaii as an example of the sort of research that should be undertaken.

A short history of tsunami research and countermeasures in Japan

PubMed Central

Shuto, Nobuo; Fujima, Koji

2009-01-01

The tsunami science and engineering began in Japan, the country the most frequently hit by local and distant tsunamis. The gate to the tsunami science was opened in 1896 by a giant local tsunami of the highest run-up height of 38 m that claimed 22,000 lives. The crucial key was a tide record to conclude that this tsunami was generated by a “tsunami earthquake”. In 1933, the same area was hit again by another giant tsunami. A total system of tsunami disaster mitigation including 10 “hard” and “soft” countermeasures was proposed. Relocation of dwelling houses to high ground was the major countermeasures. The tsunami forecasting began in 1941. In 1960, the Chilean Tsunami damaged the whole Japanese Pacific coast. The height of this tsunami was 5–6 m at most. The countermeasures were the construction of structures including the tsunami breakwater which was the first one in the world. Since the late 1970s, tsunami numerical simulation was developed in Japan and refined to become the UNESCO standard scheme that was transformed to 22 different countries. In 1983, photos and videos of a tsunami in the Japan Sea revealed many faces of tsunami such as soliton fission and edge bores. The 1993 tsunami devastated a town protected by seawalls 4.5 m high. This experience introduced again the idea of comprehensive countermeasures, consisted of defense structure, tsunami-resistant town development and evacuation based on warning. PMID:19838008

Probability-Based Design Criteria of the ASCE 7 Tsunami Loads and Effects Provisions (Invited)

NASA Astrophysics Data System (ADS)

Chock, G.

2013-12-01

Mitigation of tsunami risk requires a combination of emergency preparedness for evacuation in addition to providing structural resilience of critical facilities, infrastructure, and key resources necessary for immediate response and economic and social recovery. Critical facilities would include emergency response, medical, tsunami refuges and shelters, ports and harbors, lifelines, transportation, telecommunications, power, financial institutions, and major industrial/commercial facilities. The Tsunami Loads and Effects Subcommittee of the ASCE/SEI 7 Standards Committee is developing a proposed new Chapter 6 - Tsunami Loads and Effects for the 2016 edition of the ASCE 7 Standard. ASCE 7 provides the minimum design loads and requirements for structures subject to building codes such as the International Building Code utilized in the USA. In this paper we will provide a review emphasizing the intent of these new code provisions and explain the design methodology. The ASCE 7 provisions for Tsunami Loads and Effects enables a set of analysis and design methodologies that are consistent with performance-based engineering based on probabilistic criteria. . The ASCE 7 Tsunami Loads and Effects chapter will be initially applicable only to the states of Alaska, Washington, Oregon, California, and Hawaii. Ground shaking effects and subsidence from a preceding local offshore Maximum Considered Earthquake will also be considered prior to tsunami arrival for Alaska and states in the Pacific Northwest regions governed by nearby offshore subduction earthquakes. For national tsunami design provisions to achieve a consistent reliability standard of structural performance for community resilience, a new generation of tsunami inundation hazard maps for design is required. The lesson of recent tsunami is that historical records alone do not provide a sufficient measure of the potential heights of future tsunamis. Engineering design must consider the occurrence of events greater than scenarios in the historical record, and should properly be based on the underlying seismicity of subduction zones. Therefore, Probabilistic Tsunami Hazard Analysis (PTHA) consistent with source seismicity must be performed in addition to consideration of historical event scenarios. A method of Probabilistic Tsunami Hazard Analysis has been established that is generally consistent with Probabilistic Seismic Hazard Analysis in the treatment of uncertainty. These new tsunami design zone maps will define the coastal zones where structures of greater importance would be designed for tsunami resistance and community resilience. Structural member acceptability criteria will be based on performance objectives for a 2,500-year Maximum Considered Tsunami. The approach developed by the ASCE Tsunami Loads and Effects Subcommittee of the ASCE 7 Standard would result in the first national unification of tsunami hazard criteria for design codes reflecting the modern approach of Performance-Based Engineering.

An Evaluation of Infrastructure for Tsunami Evacuation in Padang, West Sumatra, Indonesia (Invited)

NASA Astrophysics Data System (ADS)

Cedillos, V.; Canney, N.; Deierlein, G.; Diposaptono, S.; Geist, E. L.; Henderson, S.; Ismail, F.; Jachowski, N.; McAdoo, B. G.; Muhari, A.; Natawidjaja, D. H.; Sieh, K. E.; Toth, J.; Tucker, B. E.; Wood, K.

2009-12-01

Padang has one of the world’s highest tsunami risks due to its high hazard, vulnerable terrain and population density. The current strategy to prepare for tsunamis in Padang is focused on developing early warning systems, planning evacuation routes, conducting evacuation drills, and raising local awareness. Although these are all necessary, they are insufficient. Padang’s proximity to the Sunda Trench and flat terrain make reaching safe ground impossible for much of the population. The natural warning in Padang - a strong earthquake that lasts over a minute - will be the first indicator of a potential tsunami. People will have about 30 minutes after the earthquake to reach safe ground. It is estimated that roughly 50,000 people in Padang will be unable to evacuate in that time. Given these conditions, other means to prepare for the expected tsunami must be developed. With this motivation, GeoHazards International and Stanford University’s Chapter of Engineers for a Sustainable World partnered with Indonesian organizations - Andalas University and Tsunami Alert Community in Padang, Laboratory for Earth Hazards, and the Ministry of Marine Affairs and Fisheries - in an effort to evaluate the need for and feasibility of tsunami evacuation infrastructure in Padang. Tsunami evacuation infrastructure can include earthquake-resistant bridges and evacuation structures that rise above the maximum tsunami water level, and can withstand the expected earthquake and tsunami forces. The choices for evacuation structures vary widely - new and existing buildings, evacuation towers, soil berms, elevated highways and pedestrian overpasses. This interdisciplinary project conducted a course at Stanford University, undertook several field investigations, and concluded that: (1) tsunami evacuation structures and bridges are essential to protect the people in Padang, (2) there is a need for a more thorough engineering-based evaluation than conducted to-date of the suitability of existing buildings to serve as evacuation structures, and of existing bridges to serve as elements of evacuation routes, and (3) additions to Padang’s tsunami evacuation infrastructure must carefully take into account technical matters (e.g. expected wave height, debris impact forces), social considerations (e.g. cultural acceptability, public’s confidence in the structure’s integrity), and political issues (e.g. land availability, cost, maintenance). Future plans include collaboration between U.S. and Indonesian engineers in developing designs for new tsunami evacuation structures, as well as providing training for Indonesian authorities on: (1) siting, designing, and constructing tsunami evacuation structures, and (2) evaluating the suitability of existing buildings to serve as tsunami evacuation shelters.

Tsunami in the Arctic

NASA Astrophysics Data System (ADS)

Kulikov, Evgueni; Medvedev, Igor; Ivaschenko, Alexey

2017-04-01

The severity of the climate and sparsely populated coastal regions are the reason why the Russian part of the Arctic Ocean belongs to the least studied areas of the World Ocean. In the same time intensive economic development of the Arctic region, specifically oil and gas industry, require studies of potential thread natural disasters that can cause environmental and technical damage of the coastal and maritime infrastructure of energy industry complex (FEC). Despite the fact that the seismic activity in the Arctic can be attributed to a moderate level, we cannot exclude the occurrence of destructive tsunami waves, directly threatening the FEC. According to the IAEA requirements, in the construction of nuclear power plants it is necessary to take into account the impact of all natural disasters with frequency more than 10-5 per year. Planned accommodation in the polar regions of the Russian floating nuclear power plants certainly requires an adequate risk assessment of the tsunami hazard in the areas of their location. Develop the concept of tsunami hazard assessment would be based on the numerical simulation of different scenarios in which reproduced the hypothetical seismic sources and generated tsunamis. The analysis of available geological, geophysical and seismological data for the period of instrumental observations (1918-2015) shows that the highest earthquake potential within the Arctic region is associated with the underwater Mid-Arctic zone of ocean bottom spreading (interplate boundary between Eurasia and North American plates) as well as with some areas of continental slope within the marginal seas. For the Arctic coast of Russia and the adjacent shelf area, the greatest tsunami danger of seismotectonic origin comes from the earthquakes occurring in the underwater Gakkel Ridge zone, the north-eastern part of the Mid-Arctic zone. In this area, one may expect earthquakes of magnitude Mw ˜ 6.5-7.0 at a rate of 10-2 per year and of magnitude Mw ˜ 7.5 at a rate of 10-3 per year. Additional tsunami threat might arise from rare earthquake occurrences within the continental slope of deep-sea basin of the Arctic Ocean and near the coast of the continent, where high probability of triggering submarine landslides exists that can generate even more dangerous tsunamis than those of seismotectonic origin. The most reliable information about the manifestation of the tsunami in the Arctic is associated with submarine landslide Storegga located on the continental slope of the Norwegian Sea and collapsed 8,200 years ago. Traces of sediment left behind by the tsunami waves on the coast, show that the maximum vertical tsunami runup could reach 20 meters. Factors causing the potential tsunami thread of landslides in Russian Arctic are sedimentation processes that can be associated with the formation of the alluvial fans of the great Siberian rivers Ob, Yenisei and Lena.

Chilean Tsunami Rocks the Ross Ice Shelf

NASA Astrophysics Data System (ADS)

Bromirski, P. D.; Gerstoft, P.; Chen, Z.; Stephen, R. A.; Diez, A.; Arcas, D.; Wiens, D.; Aster, R. C.; Nyblade, A.

2016-12-01

The response of the Ross Ice Shelf (RIS) to the September 16, 2015 9.3 Mb Chilean earthquake tsunami (> 75 s period) and infragravity (IG) waves (50 - 300 s period) were recorded by a broadband seismic array deployed on the RIS from November 2014 to November 2015. The array included two linear transects, one approximately orthogonal to the shelf front extending 430 km southward toward the grounding zone, and an east-west transect spanning the RIS roughly parallel to the front about 100 km south of the ice edge (https://scripps.ucsd.edu/centers/iceshelfvibes/). Signals generated by both the tsunami and IG waves were recorded at all stations on floating ice, with little ocean wave-induced energy reaching stations on grounded ice. Cross-correlation and dispersion curve analyses indicate that tsunami and IG wave-generated signals propagate across the RIS at gravity wave speeds (about 70 m/s), consistent with coupled water-ice flexural-gravity waves propagating through the ice shelf from the north. Gravity wave excitation at periods > 100 s is continuously observed during the austral winter, providing mechanical excitation of the RIS throughout the year. Horizontal displacements are typically about 3 times larger than vertical displacements, producing extensional motions that could facilitate expansion of existing fractures. The vertical and horizontal spectra in the IG band attenuate exponentially with distance from the front. Tsunami model data are used to assess variability of excitation of the RIS by long period gravity waves. Substantial variability across the RIS roughly parallel to the front is observed, likely resulting from a combination of gravity wave amplitude variability along the front, signal attenuation, incident angle of the wave forcing at the front that depends on wave generation location as well as bathymetry under and north of the shelf, and water layer and ice shelf thickness and properties.

Develop Probabilistic Tsunami Design Maps for ASCE 7

NASA Astrophysics Data System (ADS)

Wei, Y.; Thio, H. K.; Chock, G.; Titov, V. V.

2014-12-01

A national standard for engineering design for tsunami effects has not existed before and this significant risk is mostly ignored in engineering design. The American Society of Civil Engineers (ASCE) 7 Tsunami Loads and Effects Subcommittee is completing a chapter for the 2016 edition of ASCE/SEI 7 Standard. Chapter 6, Tsunami Loads and Effects, would become the first national tsunami design provisions. These provisions will apply to essential facilities and critical infrastructure. This standard for tsunami loads and effects will apply to designs as part of the tsunami preparedness. The provisions will have significance as the post-tsunami recovery tool, to plan and evaluate for reconstruction. Maps of 2,500-year probabilistic tsunami inundation for Alaska, Washington, Oregon, California, and Hawaii need to be developed for use with the ASCE design provisions. These new tsunami design zone maps will define the coastal zones where structures of greater importance would be designed for tsunami resistance and community resilience. The NOAA Center for Tsunami Research (NCTR) has developed 75 tsunami inundation models as part of the operational tsunami model forecast capability for the U.S. coastline. NCTR, UW, and URS are collaborating with ASCE to develop the 2,500-year tsunami design maps for the Pacific states using these tsunami models. This ensures the probabilistic criteria are established in ASCE's tsunami design maps. URS established a Probabilistic Tsunami Hazard Assessment approach consisting of a large amount of tsunami scenarios that include both epistemic uncertainty and aleatory variability (Thio et al., 2010). Their study provides 2,500-year offshore tsunami heights at the 100-m water depth, along with the disaggregated earthquake sources. NOAA's tsunami models are used to identify a group of sources that produce these 2,500-year tsunami heights. The tsunami inundation limits and runup heights derived from these sources establish the tsunami design map for the study site. ASCE's Energy Grad Line Analysis then uses these modeling constraints to derive hydrodynamic forces for structures within the tsunami design zone. The probabilistic tsunami design maps will be validated by comparison to state inundation maps under the coordination of the National Tsunami Hazard Mitigation Program.

Assessment of tsunami resilience of Haydarpaşa Port in the Sea of Marmara by high-resolution numerical modeling

NASA Astrophysics Data System (ADS)

Aytore, Betul; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Cankaya, Zeynep Ceren; Suzen, Mehmet Lütfi

2016-08-01

Turkey is highly prone to earthquakes because of active fault zones in the region. The Marmara region located at the western extension of the North Anatolian Fault Zone (NAFZ) is one of the most tectonically active zones in Turkey. Numerous catastrophic events such as earthquakes or earthquake/landslide-induced tsunamis have occurred in the Marmara Sea basin. According to studies on the past tsunami records, the Marmara coasts have been hit by 35 different tsunami events in the last 2000 years. The recent occurrences of catastrophic tsunamis in the world's oceans have also raised awareness about tsunamis that might take place around the Marmara coasts. Similarly, comprehensive studies on tsunamis, such as preparation of tsunami databases, tsunami hazard analysis and assessments, risk evaluations for the potential tsunami-prone regions, and establishing warning systems have accelerated. However, a complete tsunami inundation analysis in high resolution will provide a better understanding of the effects of tsunamis on a specific critical structure located in the Marmara Sea. Ports are one of those critical structures that are susceptible to marine disasters. Resilience of ports and harbors against tsunamis are essential for proper, efficient, and successful rescue operations to reduce loss of life and property. Considering this, high-resolution simulations have been carried out in the Marmara Sea by focusing on Haydarpaşa Port of the megacity Istanbul. In the first stage of simulations, the most critical tsunami sources possibly effective for Haydarpaşa Port were inputted, and the computed tsunami parameters at the port were compared to determine the most critical tsunami scenario. In the second stage of simulations, the nested domains from 90 m gird size to 10 m grid size (in the port region) were used, and the most critical tsunami scenario was modeled. In the third stage of simulations, the topography of the port and its regions were used in the two nested domains in 3-m and 1-m resolutions and the water elevations computed from the previous simulations were inputted from the border of the large domain. A tsunami numerical code, NAMI DANCE, was used in the simulations. The tsunami parameters in the highest resolution were computed in and around the port. The effect of the data resolution on the computed results has been presented. The performance of the port structures and possible effects of tsunami on port operations have been discussed. Since the harbor protection structures have not been designed to withstand tsunamis, the breakwaters' stability becomes one of the major concerns for less agitation and inundation under tsunami in Haydarpaşa Port for resilience. The flow depth, momentum fluxes, and current pattern are the other concerns that cause unexpected circulations and uncontrolled movements of objects on land and vessels in the sea.

Scenario-based tsunami risk assessment using a static flooding approach and high-resolution digital elevation data: An example from Muscat in Oman

NASA Astrophysics Data System (ADS)

Schneider, Bastian; Hoffmann, Gösta; Reicherter, Klaus

2016-04-01

Knowledge of tsunami risk and vulnerability is essential to establish a well-adapted Multi Hazard Early Warning System, land-use planning and emergency management. As the tsunami risk for the coastline of Oman is still under discussion and remains enigmatic, various scenarios based on historical tsunamis were created. The suggested inundation and run-up heights were projected onto the modern infrastructural setting of the Muscat Capital Area. Furthermore, possible impacts of the worst-case tsunami event for Muscat are discussed. The approved Papathoma Tsunami Vulnerability Assessment Model was used to model the structural vulnerability of the infrastructure for a 2 m tsunami scenario, depicting the 1945 tsunami and a 5 m tsunami in Muscat. Considering structural vulnerability, the results suggest a minor tsunami risk for the 2 m tsunami scenario as the flooding is mainly confined to beaches and wadis. Especially traditional brick buildings, still predominant in numerous rural suburbs, and a prevalently coast-parallel road network lead to an increased tsunami risk. In contrast, the 5 m tsunami scenario reveals extensively inundated areas and with up to 48% of the buildings flooded, and therefore consequently a significantly higher tsunami risk. We expect up to 60000 damaged buildings and up to 380000 residents directly affected in the Muscat Capital Area, accompanied with a significant loss of life and damage to vital infrastructure. The rapid urbanization processes in the Muscat Capital Area, predominantly in areas along the coast, in combination with infrastructural, demographic and economic growth will additionally increase the tsunami risk and therefore emphasizes the importance of tsunami risk assessment in Oman.

Oceanographer tracks marine debris from the Japan tsunami and other incidents

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-09-01

In the wake of the 11 March 2011 Tohoku earthquake and resulting tsunami that struck Japan, much of the debris that washed out to sea continues to float slowly on ocean currents across the Pacific Ocean. The leading edge of a dispersed field of debris that has not already sunk or biodegraded was estimated by a computer model to be about halfway across the Pacific, north of Midway Island, as of 31 July, 142 days after the tsunami. According to Curtis Ebbesmeyer, a consulting oceanographer who has been involved with tracking various kinds of ocean flotsam for decades, the debris field, which encompasses an area about the size of California, could begin to reach the U.S. West Coast by March 2012. The National Oceanic and Atmospheric Administration's (NOAA) Satellite and Information Service was able to track the debris field until mid-April, when the debris became too dispersed to be detected in satellite imagery. Ebbesmeyer, formerly an oceanographer with Mobil and Standard Oil, told Eos that he does not have any recent physical evidence of the debris field because it is now widely dispersed and still far away from any landfall. Ebbesmeyer said, though, that his confidence level for the debris field's estimated size and location is “very high.”

High Resolution Tsunami Modeling and Assessment of Harbor Resilience; Case Study in Istanbul

NASA Astrophysics Data System (ADS)

Cevdet Yalciner, Ahmet; Aytore, Betul; Gokhan Guler, Hasan; Kanoglu, Utku; Duzgun, Sebnem; Zaytsev, Andrey; Arikawa, Taro; Tomita, Takashi; Ozer Sozdinler, Ceren; Necmioglu, Ocal; Meral Ozel, Nurcan

2014-05-01

Ports and harbors are the major vulnerable coastal structures under tsunami attack. Resilient harbors against tsunami impacts are essential for proper, efficient and successful rescue operations and reduction of the loss of life and property by tsunami disasters. There are several critical coastal structures as such in the Marmara Sea. Haydarpasa and Yenikapi ports are located in the Marmara Sea coast of Istanbul. These two ports are selected as the sites of numerical experiments to test their resilience under tsunami impact. Cargo, container and ro-ro handlings, and short/long distance passenger transfers are the common services in both ports. Haydarpasa port has two breakwaters with the length of three kilometers in total. Yenikapi port has one kilometer long breakwater. The accurate resilience analysis needs high resolution tsunami modeling and careful assessment of the site. Therefore, building data with accurate coordinates of their foot prints and elevations are obtained. The high resolution bathymetry and topography database with less than 5m grid size is developed for modeling. The metadata of the several types of structures and infrastructure of the ports and environs are processed. Different resistances for the structures/buildings/infrastructures are controlled by assigning different friction coefficients in a friction matrix. Two different tsunami conditions - high expected and moderate expected - are selected for numerical modeling. The hybrid tsunami simulation and visualization codes NAMI DANCE, STOC-CADMAS System are utilized to solve all necessary tsunami parameters and obtain the spatial and temporal distributions of flow depth, current velocity, inundation distance and maximum water level in the study domain. Finally, the computed critical values of tsunami parameters are evaluated and structural performance of the port components are discussed in regard to a better resilience. ACKNOWLEDGEMENTS: Support by EU 603839 ASTARTE Project, UDAP-Ç-12-14 of AFAD, 108Y227 and 113M556 of TUBITAK, RAPSODI (CONCERT_Dis-021) of CONCERT-Japan Joint Call, Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey Japan-Turkey Joint Research Project by SATREPS, 2011K140210 of DPT, Istanbul Metropolitan Municipality are acknowledged.

Tsunami vulnerability and damage for buildings analyzed by means of two methods (PTVA-3 and SCHEMA) in the area of Augusta and Siracusa, eastern Sicily, Italy

NASA Astrophysics Data System (ADS)

Pagnoni, Gianluca; Tinti, Stefano

2015-04-01

The coast of the eastern Sicily is exposed to tsunamis that can be generated by local earthquakes (e.g. the 1169, 1693, 1908 events) and by earthquakes located in distant seismic zones (see the 365 AD tsunamigenic quake in Western Hellenic Arc). Tsunamis can also be generated by landslides possibly triggered by earthquakes. The Hyblean-Malta steep escarpment running offshore at a small angle with the coast is an ideal place for submarine mass failure occurrences with tsunamigenic effects. The entire eastern coast of Sicily from Messina in the north to Siracusa in the south is under the threat of tsunamis. In the frame of the FP7 European project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839), the segment of coast from Augusta to Siracusa was selected to undertake specific and detailed studies of tsunami hazard, vulnerability and damage to test existing methods and develop innovative approaches. The scope of the present work regards vulnerability and damage analyses. We chose to adopt two methods, known in the literature and briefly denoted as PTVA-3 and SCHEMA, that are based on two very different approaches, the former more qualitative and the latter more quantitative. The method PTVA-3 determines the vulnerability and damageability of a building by weighting and ranking a number of attributes covering the structural features of the edifice and the relevant characteristics of the surrounding environment such as the position with respect to the coast, the existence of defensive elements (e.g. walls, breakwaters, vegetation) and also the proximity to potential sources of floating objects that can feed damaging debris flows. On the other hand, the SCHEMA method uses a classification of building and a damage matrix that were derived from experimental fragility and damage curves first established after the Sumatra 2004 tsunami and later refined and adapted to the building stock of the Mediterranean region. The aim of this work is to compare the vulnerability and damage analyses carried out by means of the PTVA-3 and the SCHEMA methods on the same data set, that is the urban and port areas of Siracusa and Augusta in order to highlight similarities and discrepancies. In this preliminary analysis the coastal inundation was not derived from tsunami simulations, but was assumed to be constant along the coast (bathtub hypothesis) and was taken to be 5 m and 10 m respectively for Siracusa and Augusta. The main outcome of the compared analysis is that the two methods do not provide completely overlapping vulnerability and damage maps, though they use equivalent 5-degree scales. In general the PTVA-3 method tends to overestimate the damage, although there are several counterexamples where PTVA-3 foresees less damage than SCHEMA. The differences we found in the assessment opens the question of how to treat uncertainties in the vulnerability and damage analyses, which is a problem often overlooked, but of crucial importance for the application and for civil authorities.

Earth Observations taken by the Expedition 39 Crew

NASA Image and Video Library

2014-03-21

ISS039-E-003841 (21 March 2014) --- One of the Expedition 39 crew members aboard the International Space Station used an 800mm lens to record a still image documenting the unusually heavy snows which fell on northern Japan this winter. Snow highlights the flat, fenced landscape used for agriculture in this image taken on March 21, 2014. The large Tokachi River reaches the arc of the Pacific Ocean on Hokkaido?s east coast. Forests on steeper hillsides mask the snow and appear dark (upper image margin and image center). The view shows the narrow greenbelt forests that line the coast. Planted in Japan for at least the last four centuries, greenbelts protect coastlines from storms and sand movement, and are increasingly providing recreation areas. Greenbelts also reduce tsunami wave energy, protecting houses and roads from floating debris. Greenbelt forests reduced the destructive effects of the 2011 tsunami at Sendai by ?catching? entire seagoing vessels, preventing them from being washed inland.

Impacts of the June 23, 2001 Peru Tsunami

NASA Astrophysics Data System (ADS)

Dengler, L.

2001-12-01

The tsunami generated by the June 23, 2001 Peru earthquake caused significant damage to a 20-km long stretch of coastline in the Municipality of Camana, southern Peru. Over 3000 structures were damaged or destroyed and 2000 hectares of farmland flooded and covered with sand. 22 people were killed in the Municipality and 62 were reported missing. All of the casualties were attributed to the tsunami; in Camana the earthquake produced Modified Mercalli Intensities only of VI or VII. The International Tsunami Survey Team (ITST) were in Peru July 5 - 15 and measured inundation, spoke with City, Red Cross, and Health Department officials, and interviewed survivors. The preliminary ITST findings: All eyewitnesses described an initial draw-down that lasted a substantial amount of time (15 minutes or more). The initial positive wave was small, followed by two destructive waves of near similar impact. Observing the water recede was the key to self-evacuation. No one responded to the ground shaking even though all felt the earthquake strongly. Damage was concentrated along a flat coastal beach no higher than 5 m above sea level. The largest waves (5 to 8 meters) produced by this tsunami coincided with the most developed beach area along the southern Peruvian coast. Tsunami waves penetrated 1.2-km inland and damaged or destroyed nearly all of the structures in this zone. Poorly built adobe and infilled wall structures performed very poorly in the tsunami impacted area. The few structures that survived appeared to have deeper foundations and more reinforcing. The most tsunami-vulnerable populations were newcomers to the coast. Most victims were farm workers and domestic summerhouse sitters who had not grown up along the coast and were unaware of tsunami hazards. Economic impacts are likely to last a long time. The main industries in Camana are tourism and agriculture and the tsunami damaged both. While the extent of inundation and the number of structures damaged or destroyed was significant, the number of lives lost was considerably less than during several other recent tsunamis. The difference in casualties is due to several factors: 1) A tsunami-aware coastal population. Most of the people interviewed knew what tsunamis were, recognized the water draw down as a sign of danger and self-evacuated. 2) Time of year. The earthquake and tsunami occurred in winter. The summer resident population of the Camana beach towns increases by 5000 people plus an additional influx of tourists. Had the same earthquake occurred in the summer when the beach discotheques, hotels and cafes were full, casualties could have been orders of magnitude higher. 3) Time of day. The earthquake and tsunami occurred in mid-afternoon. Seeing the water retreat was the key to self-evacuation. Had the earthquake occurred at nighttime, fewer people may have responded. 4) Ambient tide level. The tsunami coincided with a minus 40 cm tide, one of the lowest tides of the year. 5) Initial drawdown of water and period of wave. Even people who were unaware of tsunamis thought the noticeable recession of the water very unusual and had time to reach higher ground.

Recent Advances in Tsunami-Seabed-Structure Interaction from Geotechnical and Hydrodynamic Perspectives

NASA Astrophysics Data System (ADS)

Sassa, S.

2017-12-01

This presentation shows some recent research advances on tsunami-seabed-structure interaction following the 2011 Tohoku Earthquake Tsunami, Japan. It presents a concise summary and discussion of utilizing a geotechnical centrifuge and a large-scale hydro flume for the modelling of tsunami-seabed-structure interaction. I highlight here the role of tsunami-induced seepage in piping/boiling, erosion and bearing capacity decrease and failure of the rubble/seabed foundation. A comparison and discussion are made on the stability assessment for the design of tsunami-resistant structures on the basis of the results from both geo-centrifuge and large-scale hydrodynamic experiments. The concurrent processes of the instability involving the scour of the mound/sandy seabed, bearing capacity failure and flow of the foundation and the failure of caisson breakwaters under tsunami overflow and seepage coupling are made clear in this presentation. Three series of experiments were conducted under fifty gravities. The first series of experiments targeted the instability of the mounds themselves, and the second series of experiments clarified how the mound scour would affect the overall stability of the caissons. The third series of experiments examined the effect of a countermeasure on the basis of the results from the two series of experiments. The experimental results first demonstrated that the coupled overflow-seepage actions promoted the development of the mound scour significantly, and caused bearing capacity failure of the mound, resulting in the total failure of the caisson breakwater, which otherwise remained stable without the coupling effect. The velocity vectors obtained from the high-resolution image analysis illustrated the series of such concurrent scour/bearing-capacity-failure/flow processes leading to the instability of the breakwater. The stability of the breakwaters was significantly improved with decreasing hydraulic gradient underneath the caissons due to an embankment effect. These findings elucidate the crucial role of overflow/seepage coupling in tsunami-seabed-structure interaction from both geotechnical and hydrodynamic perspectives, as an interdisciplinary tsunami science, warranting an enhanced disaster resilience.

Measuring the Ice Floe Sizes of the Lake Akkeshi Broken by 2011 Tohoku Pacific-Coast Earthquake

NASA Astrophysics Data System (ADS)

Abe, T.; Yoshikawa, Y.

2012-12-01

Water level fluctuations in an open sea can sometimes cause large oscillations of water level in partially enclosed bodies of water such as lakes and bays. In cold and snowy regions, flooding caused by water level fluctuation and scattering of ice floes can occur due to these secondary undulation of tide, which little studies have assessed. The tsunami caused by 2011 Tohoku Pacific-Coast Earthquake reached the coast of Hokkaido, Japan. This tsunami broke up the ice on an unprecedented scale in the Lake Akkeshi, which is connected with Akkeshi Bay. Also, the intermittent tsunami intrusion caused a serious damage to local oyster fishery. On the other hand, lake ice was not broken in other lakes near the coast lines unconnected to the open sea. Therefore, in the Lake Akkeshi, the main cause of the ice breakup is thought to have been the tsunami intrusion. In this study, the sizes of floating lake ice were measured to clarify the effect of the tsunami and the water level fluctuation on lake ice. We used satellite images by WorldView-2 sensor obtained on March 9 and March 12, 2011. We measured the sizes and areas of lake ice by GIS analysis to compare these with the results from other sea ice size measurement and then attempted to clarify the difference in sizes from ice formed in sea ice zones. Firstly, we measured the area of lake ice formed before the tsunami intrusions. From the photograph obtained on March 12, we extracted the contours of ice floes formed by the tsunami. Based on the contours, we measured the areas and diameter d of floes. In the photograph obtained on March 9, the area of lake ice was estimated as about 15 km2. The figure shows a cumulative number distribution of floe diameter d on March 12. It is noticed from the figure that the graph is almost linear for the d between 8m and 20m. In other words, this means for this range N(d) behaves like d-α; that is, the floe size distribution is basically self-similar. Note that the value α=3.0 is significantly greater than the past results of 1.2<α<2.5. Moreover, diameter d notably deviated from the line for d larger than 30m. This is because some ice floes were not affected by the tsunami, while others were broken into pieces by mechanical breakup due to water level fluctuations by tsunami oscillations. In this study, the size distribution of lake ice floes broken by a tsunami is evaluated for the first time in a lake. It is revealed that there are some regimes for diameters of floes and the significant impact of the tsunami on breakup was discussed.; The cumulative number distribution of floe diameter N(d).

Structural Changes in Molluscan Community over a 15-Year Period before and after the 2011 Great East Japan Earthquake and Subsequent Tsunami around Matsushima Bay, Miyagi Prefecture, Northeastern Japan.

PubMed

Sato, Shin'ichi; Chiba, Tomoki

2016-01-01

We examined structural changes in the molluscan community for ten years (2001-2010) before and five years (2011-2015) after the 2011 Great East Japan Earthquake and subsequent tsunami around Matsushima Bay, Miyagi Prefecture, northeastern Japan. Before the earthquake and tsunami, Ruditapes philippinarum, Macoma incongrua, Pillucina pisidium, and Batillaria cumingii were dominant, and an alien predator Laguncula pulchella appeared in 2002 and increased in number. After the tsunami, R. philippinarum and M. incongrua populations quickly recovered in 2012, but P. pisidium and B. cumingii populations did not recover until 2015. By contrast, Musculista senhousia, Mya arenaria, Retusa sp., and Solen strictus were found in low densities before the tsunami, but they rapidly increased in abundance/number over five years after the tsunami. These results suggest that the molluscan community on the Tona Coast was drastically changed by the earthquake and tsunami, and some species mainly inhabiting the intertidal-subtidal zone may have increased in number because of land subsidence. We also emphasize that the seawall delayed recovery of the intertidal community after the earthquake and tsunami.

Structural Changes in Molluscan Community over a 15-Year Period before and after the 2011 Great East Japan Earthquake and Subsequent Tsunami around Matsushima Bay, Miyagi Prefecture, Northeastern Japan

PubMed Central

Chiba, Tomoki

2016-01-01

We examined structural changes in the molluscan community for ten years (2001–2010) before and five years (2011–2015) after the 2011 Great East Japan Earthquake and subsequent tsunami around Matsushima Bay, Miyagi Prefecture, northeastern Japan. Before the earthquake and tsunami, Ruditapes philippinarum, Macoma incongrua, Pillucina pisidium, and Batillaria cumingii were dominant, and an alien predator Laguncula pulchella appeared in 2002 and increased in number. After the tsunami, R. philippinarum and M. incongrua populations quickly recovered in 2012, but P. pisidium and B. cumingii populations did not recover until 2015. By contrast, Musculista senhousia, Mya arenaria, Retusa sp., and Solen strictus were found in low densities before the tsunami, but they rapidly increased in abundance/number over five years after the tsunami. These results suggest that the molluscan community on the Tona Coast was drastically changed by the earthquake and tsunami, and some species mainly inhabiting the intertidal—subtidal zone may have increased in number because of land subsidence. We also emphasize that the seawall delayed recovery of the intertidal community after the earthquake and tsunami. PMID:27936182

Improving tsunami resiliency: California's Tsunami Policy Working Group

USGS Publications Warehouse

Real, Charles R.; Johnson, Laurie; Jones, Lucile M.; Ross, Stephanie L.; Kontar, Y.A.; Santiago-Fandiño, V.; Takahashi, T.

2014-01-01

California has established a Tsunami Policy Working Group to facilitate development of policy recommendations for tsunami hazard mitigation. The Tsunami Policy Working Group brings together government and industry specialists from diverse fields including tsunami, seismic, and flood hazards, local and regional planning, structural engineering, natural hazard policy, and coastal engineering. The group is acting on findings from two parallel efforts: The USGS SAFRR Tsunami Scenario project, a comprehensive impact analysis of a large credible tsunami originating from an M 9.1 earthquake in the Aleutian Islands Subduction Zone striking California’s coastline, and the State’s Tsunami Preparedness and Hazard Mitigation Program. The unique dual-track approach provides a comprehensive assessment of vulnerability and risk within which the policy group can identify gaps and issues in current tsunami hazard mitigation and risk reduction, make recommendations that will help eliminate these impediments, and provide advice that will assist development and implementation of effective tsunami hazard risk communication products to improve community resiliency.

Modeling the propagation, transformation and the impact of tsunami on urban areas using the coupling STOC-ML/IC/CADMAS in nested grids - Application to specific sites of Chile to improve the tsunami induced loads prediction.

NASA Astrophysics Data System (ADS)

Mokrani, C.; Catalan, P. A.; Cienfuegos, R.; Arikawa, T.

2016-02-01

A large part of coasts around the world are affected by tsunami impacts, which supposes a challenge when designing coastal protection structures. Numerical models provide predictions of tsunami-induced loads and there time evolution, which can be used to improve sizing rules of coastal structures. However, the numerical assessment of impact loads is an hard stake. Indeed, recent experimental studies have shown that pressure dynamics generated during tsunami impacts are highly sensitive to the incident local shape of the tsunami. Therefore, high numerical resolutions and very accurate models are required to model all stages during which the tsunami shape is modified before the impact. Given the large distances involved in tsunami events, this can be disregarded in favor of computing time. The Port and Airport Research Institute (PARI) has recently developed a three-way coupled model which allows to accurately model the incident tsunami shape while maintaining reasonable computational time. This coupling approach uses three models used in nested grids (cf. Figure 1). The first one (STOC-ML) solves Nonlinear Shallow Water Equations with hydrostatic pressure. It is used to model the tsunami propagation off the coast. The second one (STOC-IC) is a 3D non-hydrostatic model, on which the free-surface position is estimated through the integrated continuity equation. It has shown to accurately describe dispersive and weakly linear effects occurring at the coast vicinity. The third model (CADMAS-SURF) solves fully three-dimensional Navier-Stokes equations and use a VOF method. Highly nonlinear, dispersive effects and wave breaking processes can be included at the wave scale and therefore, a very accurate description of the incident tsunami is provided. Each model have been separately validated from analytical and/or experimental data. The present objective is to highlight recent advances in Coastal Ocean modeling for tsunami modeling and loads prediction by applying this coupling approach to different sites of the Chilean coast. We first present validation tests to highlight the numerical abilities of this coupling. Then, two tsunami cases are considered and both near-shore processes and tsunami-induced loads on structures are analyzed.

Benchmarking on Tsunami Currents with ComMIT

NASA Astrophysics Data System (ADS)

Sharghi vand, N.; Kanoglu, U.

2015-12-01

There were no standards for the validation and verification of tsunami numerical models before 2004 Indian Ocean tsunami. Even, number of numerical models has been used for inundation mapping effort, evaluation of critical structures, etc. without validation and verification. After 2004, NOAA Center for Tsunami Research (NCTR) established standards for the validation and verification of tsunami numerical models (Synolakis et al. 2008 Pure Appl. Geophys. 165, 2197-2228), which will be used evaluation of critical structures such as nuclear power plants against tsunami attack. NCTR presented analytical, experimental and field benchmark problems aimed to estimate maximum runup and accepted widely by the community. Recently, benchmark problems were suggested by the US National Tsunami Hazard Mitigation Program Mapping & Modeling Benchmarking Workshop: Tsunami Currents on February 9-10, 2015 at Portland, Oregon, USA (http://nws.weather.gov/nthmp/index.html). These benchmark problems concentrated toward validation and verification of tsunami numerical models on tsunami currents. Three of the benchmark problems were: current measurement of the Japan 2011 tsunami in Hilo Harbor, Hawaii, USA and in Tauranga Harbor, New Zealand, and single long-period wave propagating onto a small-scale experimental model of the town of Seaside, Oregon, USA. These benchmark problems were implemented in the Community Modeling Interface for Tsunamis (ComMIT) (Titov et al. 2011 Pure Appl. Geophys. 168, 2121-2131), which is a user-friendly interface to the validated and verified Method of Splitting Tsunami (MOST) (Titov and Synolakis 1995 J. Waterw. Port Coastal Ocean Eng. 121, 308-316) model and is developed by NCTR. The modeling results are compared with the required benchmark data, providing good agreements and results are discussed. Acknowledgment: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe)

Fusion of real-time simulation, sensing, and geo-informatics in assessing tsunami impact

NASA Astrophysics Data System (ADS)

Koshimura, S.; Inoue, T.; Hino, R.; Ohta, Y.; Kobayashi, H.; Musa, A.; Murashima, Y.; Gokon, H.

2015-12-01

Bringing together state-of-the-art high-performance computing, remote sensing and spatial information sciences, we establish a method of real-time tsunami inundation forecasting, damage estimation and mapping to enhance disaster response. Right after a major (near field) earthquake is triggered, we perform a real-time tsunami inundation forecasting with use of high-performance computing platform (Koshimura et al., 2014). Using Tohoku University's vector supercomputer, we accomplished "10-10-10 challenge", to complete tsunami source determination in 10 minutes, tsunami inundation modeling in 10 minutes with 10 m grid resolution. Given the maximum flow depth distribution, we perform quantitative estimation of exposed population using census data and mobile phone data, and the numbers of potential death and damaged structures by applying tsunami fragility curve. After the potential tsunami-affected areas are estimated, the analysis gets focused and moves on to the "detection" phase using remote sensing. Recent advances of remote sensing technologies expand capabilities of detecting spatial extent of tsunami affected area and structural damage. Especially, a semi-automated method to estimate building damage in tsunami affected areas is developed using pre- and post-event high-resolution SAR (Synthetic Aperture Radar) data. The method is verified through the case studies in the 2011 Tohoku and other potential tsunami scenarios, and the prototype system development is now underway in Kochi prefecture, one of at-risk coastal city against Nankai trough earthquake. In the trial operation, we verify the capability of the method as a new tsunami early warning and response system for stakeholders and responders.

A Preliminary Tsunami Vulnerability Analysis for Yenikapi Region in Istanbul

NASA Astrophysics Data System (ADS)

Ceren Cankaya, Zeynep; Suzen, Lutfi; Cevdet Yalciner, Ahmet; Kolat, Cagil; Aytore, Betul; Zaytsev, Andrey

2015-04-01

One of the main requirements during post disaster recovery operations is to maintain proper transportation and fluent communication at the disaster areas. Ports and harbors are the main transportation hubs which must work with proper performance at all times especially after the disasters. Resilience of coastal utilities after earthquakes and tsunamis have major importance for efficient and proper rescue and recovery operations soon after the disasters. Istanbul is a mega city with its various coastal utilities located at the north coast of the Sea of Marmara. At Yenikapi region of Istanbul, there are critical coastal utilities and vulnerable coastal structures and critical activities occur daily. Fishery ports, commercial ports, small craft harbors, passenger terminals of intercity maritime transportation, water front commercial and/or recreational structures are some of the examples of coastal utilization which are vulnerable against marine disasters. Therefore their vulnerability under tsunami or any other marine hazard to Yenikapi region of Istanbul is an important issue. In this study, a methodology of vulnerability analysis under tsunami attack is proposed with the applications to Yenikapi region. In the study, high resolution (1m) GIS database of Istanbul Metropolitan Municipality (IMM) is used and analyzed by using GIS implementation. The bathymetry and topography database and the vector dataset containing all buildings/structures/infrastructures in the study area are obtained for tsunami numerical modeling for the study area. GIS based tsunami vulnerability assessment is conducted by applying the Multi-criteria Decision Making Analysis (MCDA). The tsunami parameters from deterministically defined worst case scenarios are computed from the simulations using tsunami numerical model NAMI DANCE. The vulnerability parameters in the region due to two different classifications i) vulnerability of buildings/structures and ii) vulnerability of (human) evacuation are defined and scored. The risk level is computed using tsunami intensity (level of flow depth from simulations) and vulnerability (structural and human-based) at each node in Yenikapi. The results are presented at high resolution (1m) and discussed. Acknowledgements: Partial support by EU 603839 ASTARTE Project, UDAP-C-12-14 of AFAD of Turkey, 108Y227 and 113M556 of TUBITAK Turkey, RAPSODI (CONCERT_Dis-021) of CONCERT-Japan Joint Call, 2011K140210 of DPT, Istanbul Metropolitan Municipality, Japan-Turkey Joint Research Project by JICA on earthquakes and tsunamis in Marmara Region by SATREPS are acknowledged.

Perceived community participation in tsunami recovery efforts and the mental health of tsunami-affected mothers: findings from a study in rural Sri Lanka.

PubMed

Wickrama, K A S; Wickrama, T

2011-09-01

The 2004 tsunami seriously affected millions of families in several developing countries by destroying their livelihoods, houses and communities, subsequently damaging social and physical resources. Disaster studies have documented that both post-traumatic stress disorder (PTSD) and depression develop during the first six months following disaster exposure for the majority of those afflicted. and Using data from 325 tsunami-affected families living in southern Sri Lanka, the current study investigates whether community social resources such as residents' perceived community participation in tsunami recovery efforts reduce mental health risks (PTSD and depressive symptoms) of tsunami-affected mothers. The analysis is based on structural equation modelling. and The findings of structural equation modelling supports the main hypothesis that residents' perceived community participation directly and indirectly (through collective family functioning and mental health service use) reduces mental health risks (both PTSD and depressive symptoms) of tsunami-affected mothers after controlling for pre-tsunami family adversities. In addition, the results show that residents' perceived community participation buffers the influence of trauma exposure on PTSD symptom levels of mothers. The identification of specific social and family processes that relate to mental health can be useful for post-disaster interventions and recovery programmes.

Modeling Extra-Long Tsunami Propagation: Assessing Data, Model Accuracy and Forecast Implications

NASA Astrophysics Data System (ADS)

Titov, V. V.; Moore, C. W.; Rabinovich, A.

2017-12-01

Detecting and modeling tsunamis propagating tens of thousands of kilometers from the source is a formidable scientific challenge and seemingly satisfies only scientific curiosity. However, results of such analyses produce a valuable insight into the tsunami propagation dynamics, model accuracy and would provide important implications for tsunami forecast. The Mw = 9.3 megathrust earthquake of December 26, 2004 off the coast of Sumatra generated a tsunami that devastated Indian Ocean coastlines and spread into the Pacific and Atlantic oceans. The tsunami was recorded by a great number of coastal tide gauges, including those located in 15-25 thousand kilometers from the source area. To date, it is still the farthest instrumentally detected tsunami. The data from these instruments throughout the world oceans enabled to estimate various statistical parameters and energy decay of this event. High-resolution records of this tsunami from DARTs 32401 (offshore of northern Chile), 46405 and NeMO (both offshore of the US West Coast), combined with the mainland tide gauge measurements enabled us to examine far-field characteristics of the 2004 in the Pacific Ocean and to compare the results of global numerical simulations with the observations. Despite their small heights (less than 2 cm at deep-ocean locations), the records demonstrated consistent spatial and temporal structure. The numerical model described well the frequency content, amplitudes and general structure of the observed waves at deep-ocean and coastal gages. We present analysis of the measurements and comparison with model data to discuss implication for tsunami forecast accuracy. Model study for such extreme distances from the tsunami source and at extra-long times after the event is an attempt to find accuracy bounds for tsunami models and accuracy limitations of model use for forecast. We discuss results in application to tsunami model forecast and tsunami modeling in general.

Lessons on vulnerability from the 2011 Tohoku earthquake for Indonesia and the United States

NASA Astrophysics Data System (ADS)

Sugimoto, M.; Dengler, L.

2011-12-01

The 2011 Tohoku earthquake and tsunami shocked people relevant for tsunami disaster risk reduction all over the world because such people thought Tohoku has often attacked by tsunamis and has declared one of the most wellprepared areas for tsunami in the world. Each author has separately promoted tsunami education to community in Indonesia for 7 years after the 2004 Indian Ocean tsunami and California US for 19 years after the1992 M7.2 Cape Mendocino earthquake. In order to learn the lesson from the 2011 Tohoku earthquake and tsunami and feedback to Indonesia, US and International society, we examined some of the factors that contributed to impacts in Tohoku based on field reconnaissance and reports from other organizations. The biggest factors exacerbating losses were the underestimation M8 of the real tsunami size M9 in design of prevention structures and evacuation planning coupled with a perception of individuals that they were not at risk. Approximately 86 % of the tsunami victims were in areas outside the mapped tsunami hazard zone in Unosumai town, Iwate. At least 100 chosen tsunami evacuation buildings were either overtopped or structurally toppled by the tsunami. More than 200 people died in the first story gymnasium of elementary school beside the river and canal in areas outside the mapped tsunami hazard zone in Higashi-Matsushima city Miyagi. Around 80 students sacrificed in Okawa Elementary school in Ishinomaki city Miyagi. Additional factors affecting vulnerability included people who were in safe areas at the time of the earthquake, returning to hazard zones after feeling the earthquake to rescue relatives or possessions, and relying on cars for evacuation. Factors that enhanced resilience include the good performance of most structures to earthquake ground shaking and the performance of the tsunami early warning system in stopping trains and shutting down other critical systems. Although power was out in most of the affected region, some cell phones and automobile car radios worked in many areas and were able to provide some warning guidance. Individuals who were able to improvise and make changes in their evacuation plans and routes may have been more likely to survive. As for US, it has triggered a re-examination of how slip and secondary fault rupture may affect the size of the tsunami and engendered debate about how to treat uncertainty in model results while it has not changed the maximum magnitude estimate for an earthquake on the Cascadia subduction zone, it has triggered a re-examination of how slip and secondary fault rupture may affect the size of the tsunami and engendered debate about how to treat uncertainty in model results. It has also raised the priority of FEMA's catastrophic response planning efforts for a great Cascadia earthquake and has invigorated states and local coastal jurisdiction's planning, education, and outreach efforts. Indonesia has been on the way to prepare for tsunami from the Tohoku model after the 2004 Indian Ocean tsunami. I stopped the plan make signboards of numerical tsunami height in Padang Indonesia because such signboards were not effective in Tohoku in this time. We introduce new plans in this presentation.

Benchmarking an Unstructured-Grid Model for Tsunami Current Modeling

NASA Astrophysics Data System (ADS)

Zhang, Yinglong J.; Priest, George; Allan, Jonathan; Stimely, Laura

2016-12-01

We present model results derived from a tsunami current benchmarking workshop held by the NTHMP (National Tsunami Hazard Mitigation Program) in February 2015. Modeling was undertaken using our own 3D unstructured-grid model that has been previously certified by the NTHMP for tsunami inundation. Results for two benchmark tests are described here, including: (1) vortex structure in the wake of a submerged shoal and (2) impact of tsunami waves on Hilo Harbor in the 2011 Tohoku event. The modeled current velocities are compared with available lab and field data. We demonstrate that the model is able to accurately capture the velocity field in the two benchmark tests; in particular, the 3D model gives a much more accurate wake structure than the 2D model for the first test, with the root-mean-square error and mean bias no more than 2 cm s-1 and 8 mm s-1, respectively, for the modeled velocity.

Real-time tsunami inundation forecasting and damage mapping towards enhancing tsunami disaster resiliency

NASA Astrophysics Data System (ADS)

Koshimura, S.; Hino, R.; Ohta, Y.; Kobayashi, H.; Musa, A.; Murashima, Y.

2014-12-01

With use of modern computing power and advanced sensor networks, a project is underway to establish a new system of real-time tsunami inundation forecasting, damage estimation and mapping to enhance society's resilience in the aftermath of major tsunami disaster. The system consists of fusion of real-time crustal deformation monitoring/fault model estimation by Ohta et al. (2012), high-performance real-time tsunami propagation/inundation modeling with NEC's vector supercomputer SX-ACE, damage/loss estimation models (Koshimura et al., 2013), and geo-informatics. After a major (near field) earthquake is triggered, the first response of the system is to identify the tsunami source model by applying RAPiD Algorithm (Ohta et al., 2012) to observed RTK-GPS time series at GEONET sites in Japan. As performed in the data obtained during the 2011 Tohoku event, we assume less than 10 minutes as the acquisition time of the source model. Given the tsunami source, the system moves on to running tsunami propagation and inundation model which was optimized on the vector supercomputer SX-ACE to acquire the estimation of time series of tsunami at offshore/coastal tide gauges to determine tsunami travel and arrival time, extent of inundation zone, maximum flow depth distribution. The implemented tsunami numerical model is based on the non-linear shallow-water equations discretized by finite difference method. The merged bathymetry and topography grids are prepared with 10 m resolution to better estimate the tsunami inland penetration. Given the maximum flow depth distribution, the system performs GIS analysis to determine the numbers of exposed population and structures using census data, then estimates the numbers of potential death and damaged structures by applying tsunami fragility curve (Koshimura et al., 2013). Since the tsunami source model is determined, the model is supposed to complete the estimation within 10 minutes. The results are disseminated as mapping products to responders and stakeholders, e.g. national and regional municipalities, to be utilized for their emergency/response activities. In 2014, the system is verified through the case studies of 2011 Tohoku event and potential earthquake scenarios along Nankai Trough with regard to its capability and robustness.

Tsunami Simulators in Physical Modelling - Concept to Practical Solutions

NASA Astrophysics Data System (ADS)

Chandler, Ian; Allsop, William; Robinson, David; Rossetto, Tiziana; McGovern, David; Todd, David

2017-04-01

Whilst many researchers have conducted simple 'tsunami impact' studies, few engineering tools are available to assess the onshore impacts of tsunami, with no agreed methods available to predict loadings on coastal defences, buildings or related infrastructure. Most previous impact studies have relied upon unrealistic waveforms (solitary or dam-break waves and bores) rather than full-duration tsunami waves, or have used simplified models of nearshore and over-land flows. Over the last 10+ years, pneumatic Tsunami Simulators for the hydraulic laboratory have been developed into an exciting and versatile technology, allowing the forces of real-world tsunami to be reproduced and measured in a laboratory environment for the first time. These devices have been used to model generic elevated and N-wave tsunamis up to and over simple shorelines, and at example coastal defences and infrastructure. They have also reproduced full-duration tsunamis including Mercator 2004 and Tohoku 2011, both at 1:50 scale. Engineering scale models of these tsunamis have measured wave run-up on simple slopes, forces on idealised sea defences, pressures / forces on buildings, and scour at idealised buildings. This presentation will describe how these Tsunami Simulators work, demonstrate how they have generated tsunami waves longer than the facilities within which they operate, and will present research results from three generations of Tsunami Simulators. Highlights of direct importance to natural hazard modellers and coastal engineers include measurements of wave run-up levels, forces on single and multiple buildings and comparison with previous theoretical predictions. Multiple buildings have two malign effects. The density of buildings to flow area (blockage ratio) increases water depths and flow velocities in the 'streets'. But the increased building densities themselves also increase the cost of flow per unit area (both personal and monetary). The most recent study with the Tsunami Simulators therefore focussed on the influence of multiple buildings (up to 4 rows) which showed (for instance) that the greatest forces can act on the landward (not seaward) rows of buildings. Studies in the 70m long, 4m wide main channel of the Fast Flow Facility on tsunami defence structures have also measured forces on buildings in the lee of a failed defence wall and tsunami induced scour. Supporting presentations at this conference: McGovern et al on tsunami induced scour at coastal structures and Foster et al on building loads.

Tsunami hazard maps of spanish coast at national scale from seismic sources

NASA Astrophysics Data System (ADS)

Aniel-Quiroga, Íñigo; González, Mauricio; Álvarez-Gómez, José Antonio; García, Pablo

2017-04-01

Tsunamis are a moderately frequent phenomenon in the NEAM (North East Atlantic and Mediterranean) region, and consequently in Spain, as historic and recent events have affected this area. I.e., the 1755 earthquake and tsunami affected the Spanish Atlantic coasts of Huelva and Cadiz and the 2003 Boumerdés earthquake triggered a tsunami that reached Balearic island coast in less than 45 minutes. The risk in Spain is real and, its population and tourism rate makes it vulnerable to this kind of catastrophic events. The Indian Ocean tsunami in 2004 and the tsunami in Japan in 2011 launched the worldwide development and application of tsunami risk reduction measures that have been taken as a priority in this field. On November 20th 2015 the directive of the Spanish civil protection agency on planning under the emergency of tsunami was presented. As part of the Spanish National Security strategy, this document specifies the structure of the action plans at different levels: National, regional and local. In this sense, the first step is the proper evaluation of the tsunami hazard at National scale. This work deals with the assessment of the tsunami hazard in Spain, by means of numerical simulations, focused on the elaboration of tsunami hazard maps at National scale. To get this, following a deterministic approach, the seismic structures whose earthquakes could generate the worst tsunamis affecting the coast of Spain have been compiled and characterized. These worst sources have been propagated numerically along a reconstructed bathymetry, built from the best resolution available data. This high-resolution bathymetry was joined with a 25-m resolution DTM, to generate continuous offshore-onshore space, allowing the calculation of the flooded areas prompted by each selected source. The numerical model applied for the calculation of the tsunami propagations was COMCOT. The maps resulting from the numerical simulations show not only the tsunami amplitude at coastal areas but also the run-up and inundation length from the coastline. The run-up has been calculated with numerical model, complemented with an alternative method, based on interpolation on a tsunami run-up database created ad hoc. These estimated variables allow the identification of the most affected areas in case of tsunami and they are also the base for the local authorities to evaluate the necessity of new higher resolution studies at local scale on specific areas.

Seismic behavior of breakwaters on complex ground by numerical tests: Liquefaction and post liquefaction ground settlements

NASA Astrophysics Data System (ADS)

Gu, Linlin; Zhang, Feng; Bao, Xiaohua; Shi, Zhenming; Ye, Guanlin; Ling, Xianzhang

2018-04-01

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from tsunamis. There is a risk that foundation soils of these structures may liquefy, or partially liquefy during the earthquake preceding a tsunami, which would greatly reduce the structures' capacity to resist the tsunami. It is necessary to consider not only the soil's liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater's capacity to resist an incoming tsunami. In this study, numerical tests based on a sophisticated constitutive model and a soil-water coupled finite element method are used to predict the mechanical behavior of breakwaters and the surrounding soils. Two real breakwaters subjected to two different seismic excitations are examined through numerical simulation. The simulation results show that, earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation. A soil profile with thick clayey layers beneath liquefied soil is more vulnerable to tsunami than a soil profile with only sandy layers. Therefore, quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

18 CFR 1304.400 - Flotation devices and material, all floating structures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating structures. (a) All flotation for docks, boat mooring buoys, and other water-use structures and facilities...

18 CFR 1304.400 - Flotation devices and material, all floating structures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating structures. (a) All flotation for docks, boat mooring buoys, and other water-use structures and facilities...

18 CFR 1304.400 - Flotation devices and material, all floating structures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating structures. (a) All flotation for docks, boat mooring buoys, and other water-use structures and facilities...

Effects of floating gate structures on the two-dimensional electron gas density and electron mobility in AlGaN/AlN/GaN heterostructure field-effect transistors

NASA Astrophysics Data System (ADS)

Zhao, Jingtao; Zhao, Zhenguo; Chen, Zidong; Lin, Zhaojun; Xu, Fukai

2017-12-01

In this study, we have investigated the electrical properties of the AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with floating gate structures using the measured capacitancevoltage (C-V) and current-voltage (I-V) characteristics. It is found that the two-dimensional electron gas (2DEG) density under the central gate cannot be changed by the floating gate structures. However, the floating gate structures can cause the strain variation in the barrier layer, which lead to the non-uniform distribution of the polarization charges, then induce a polarization Coulomb field and scatter the 2DEG. More floating gate structures and closer distance between the floating gates and the central gate will result in stronger scattering effect of the 2DEG.

A new GIS-based tsunami risk evaluation: MeTHuVA (METU tsunami human vulnerability assessment) at Yenikapı, Istanbul

NASA Astrophysics Data System (ADS)

Cankaya, Zeynep Ceren; Suzen, Mehmet Lutfi; Yalciner, Ahmet Cevdet; Kolat, Cagil; Zaytsev, Andrey; Aytore, Betul

2016-07-01

Istanbul is a mega city with various coastal utilities located on the northern coast of the Sea of Marmara. At Yenikapı, there are critical vulnerable coastal utilities, structures, and active metropolitan life. Fishery ports, commercial ports, small craft harbors, passenger terminals of intercity maritime transportation, waterfront commercial and/or recreational structures with residential/commercial areas and public utility areas are some examples of coastal utilization that are vulnerable to marine disasters. Therefore, the tsunami risk in the Yenikapı region is an important issue for Istanbul. In this study, a new methodology for tsunami vulnerability assessment for areas susceptible to tsunami is proposed, in which the Yenikapı region is chosen as a case study. Available datasets from the Istanbul Metropolitan Municipality and Turkish Navy are used as inputs for high-resolution GIS-based multi-criteria decision analysis (MCDA) evaluation of tsunami risk in Yenikapı. Bathymetry and topography database is used for high-resolution tsunami numerical modeling where the tsunami hazard, in terms of coastal inundation, is deterministically computed using the NAMI DANCE numerical code, considering earthquake worst case scenarios. In order to define the tsunami human vulnerability of the region, two different aspects, vulnerability at location and evacuation resilience maps were created using the analytical hierarchical process (AHP) method of MCDA. A vulnerability at location map is composed of metropolitan use, geology, elevation, and distance from shoreline layers, whereas an evacuation resilience map is formed by slope, distance within flat areas, distance to buildings, and distance to road networks layers. The tsunami risk map is then computed by the proposed new relationship which uses flow depth maps, vulnerability at location maps, and evacuation resilience maps.

Development of jacket platform tsunami risk rating system in waters offshore North Borneo

NASA Astrophysics Data System (ADS)

Lee, H. E.; Liew, M. S.; Mardi, N. H.; Na, K. L.; Toloue, Iraj; Wong, S. K.

2016-09-01

This work details the simulation of tsunami waves generated by seaquakes in the Manila Trench and their effect on fixed oil and gas jacket platforms in waters offshore North Borneo. For this study, a four-leg living quarter jacket platform located in a water depth of 63m is modelled in SACS v5.3. Malaysia has traditionally been perceived to be safe from the hazards of earthquakes and tsunamis. Local design practices tend to neglect tsunami waves and include no such provisions. In 2004, a 9.3 M w seaquake occurred off the northwest coast of Aceh, which generated tsunami waves that caused destruction in Malaysia totalling US 25 million and 68 deaths. This event prompted an awareness of the need to study the reliability of fixed offshore platforms scattered throughout Malaysian waters. In this paper, we present a review of research on the seismicity of the Manila Trench, which is perceived to be high risk for Southeast Asia. From the tsunami numerical model TUNA-M2, we extract computer-simulated tsunami waves at prescribed grid points in the vicinity of the platforms in the region. Using wave heights as input, we simulate the tsunami using SACS v5.3 structural analysis software of offshore platforms, which is widely accepted by the industry. We employ the nonlinear solitary wave theory in our tsunami loading calculations for the platforms, and formulate a platform-specific risk quantification system. We then perform an intensive structural sensitivity analysis and derive a corresponding platform-specific risk rating model.

Physical experiments and analysis on the generation and evolution of tsunami-induced turbulent coherent structures

NASA Astrophysics Data System (ADS)

Kalligeris, Nikos; Lynett, Patrick

2017-11-01

Numerous historical accounts describe the formation of ``whirpools'' inside ports and harbors during tsunami events, causing port operation disruptions. Videos from the Japan 2011 tsunami revealed complex nearshore flow patters, resulting from the interaction of tsunami-induced currents with the man-made coastline, and the generation of large eddies (or turbulent coherent structures) in numerous ports and harbors near the earthquake epicenter. The aim of this work is to study the generation and evolution of tsunami-induced turbulent coherent structures (TCS) in a well-controlled environment using realistic scaling. A physical configuration is created in the image of a port entrance at a scale of 1:27 and a small-amplitude, long period wave creates a transient flow through the asymmetric harbor channel. A separated region forms, which coupled with the transient flow, leads to the formation of a stable monopolar TCS. The surface flow is examined through mono- and stereo-PTV techniques to extract surface velocity vectors. Surface velocity maps and vortex flow profiles are used to study the experimental TCS generation and evolution, and characterize the TCS structure. Analytical tools are used to describe the TCS growth rate and kinetic energy decay. This work was funded by the National Science Foundation NEES Research program, with Award Number 1135026.

Should tsunami models use a nonzero initial condition for horizontal velocity?

NASA Astrophysics Data System (ADS)

Nava, G.; Lotto, G. C.; Dunham, E. M.

2017-12-01

Tsunami propagation in the open ocean is most commonly modeled by solving the shallow water wave equations. These equations require two initial conditions: one on sea surface height and another on depth-averaged horizontal particle velocity or, equivalently, horizontal momentum. While most modelers assume that initial velocity is zero, Y.T. Song and collaborators have argued for nonzero initial velocity, claiming that horizontal displacement of a sloping seafloor imparts significant horizontal momentum to the ocean. They show examples in which this effect increases the resulting tsunami height by a factor of two or more relative to models in which initial velocity is zero. We test this claim with a "full-physics" integrated dynamic rupture and tsunami model that couples the elastic response of the Earth to the linearized acoustic-gravitational response of a compressible ocean with gravity; the model self-consistently accounts for seismic waves in the solid Earth, acoustic waves in the ocean, and tsunamis (with dispersion at short wavelengths). We run several full-physics simulations of subduction zone megathrust ruptures and tsunamis in geometries with a sloping seafloor, using both idealized structures and a more realistic Tohoku structure. Substantial horizontal momentum is imparted to the ocean, but almost all momentum is carried away in the form of ocean acoustic waves. We compare tsunami propagation in each full-physics simulation to that predicted by an equivalent shallow water wave simulation with varying assumptions regarding initial conditions. We find that the initial horizontal velocity conditions proposed by Song and collaborators consistently overestimate the tsunami amplitude and predict an inconsistent wave profile. Finally, we determine tsunami initial conditions that are rigorously consistent with our full-physics simulations by isolating the tsunami waves (from ocean acoustic and seismic waves) at some final time, and backpropagating the tsunami waves to their initial state by solving the adjoint problem. The resulting initial conditions have negligible horizontal velocity.

Tsunami Speed Variations in Density-stratified Compressible Global Oceans

NASA Astrophysics Data System (ADS)

Watada, S.

2013-12-01

Recent tsunami observations in the deep ocean have accumulated unequivocal evidence that tsunami traveltime delays compared with the linear long-wave tsunami simulations occur during tsunami propagation in the deep ocean. The delay is up to 2% of the tsunami traveltime. Watada et al. [2013] investigated the cause of the delay using the normal mode theory of tsunamis and attributed the delay to the compressibility of seawater, the elasticity of the solid earth, and the gravitational potential change associated with mass motion during the passage of tsunamis. Tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth-variable sound speeds and density gradients. For a 4-km deep ocean, the total tsunami speed reduction is 0.45% compared with incompressible homogeneous seawater; two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression. Tsunami speeds are computed for global ocean density and sound speed profiles and characteristic structures are discussed. Tsunami speed reductions are proportional to ocean depth with small variations, except for in warm Mediterranean seas. The impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of trans-oceanic tsunamis. Data locations where a vertical ocean profile deeper than 2500 m is available in World Ocean Atlas 2009. The dark gray area indicates the Pacific Ocean defined in WOA09. a) Tsunami speed variations. Red, gray and black bars represent global, Pacific, and Mediterranean Sea, respectively. b) Regression lines of the tsunami velocity reduction for all oceans. c)Vertical ocean profiles at grid points indicated by the stars in Figure 1.

The Components of Community Awareness and Preparedness; its Effects on the Reduction of Tsunami Vulnerability and Risk

NASA Astrophysics Data System (ADS)

Tufekci, Duygu; Lutfi Suzen, Mehmet; Cevdet Yalciner, Ahmet

2017-04-01

The resilience of coastal communities against tsunamis are dependent on preparedness of the communities. Preparedness covers social and structural components which increases with the awareness in the community against tsunamis. Therefore, proper evaluation of all components of preparedness will help communities to reduce the adverse effects of tsunamis and increase the overall resilience of communities. On the other hand, the complexity of the metropolitan life with its social and structural components necessitates explicit vulnerability assessments for proper determination of tsunami risk, and development of proper mitigation strategies and recovery plans. Assessing the vulnerability and resilience level of a region against tsunamis and efforts for reducing the tsunami risk are the key components of disaster management. Since increasing the awareness of coastal communities against tsunamis is one of the main objectives of disaster management, then it should be considered as one of the parameter in tsunami risk analysis. In the method named MetHuVA (METU - Metropolitan Human Tsunami Vulnerability Assessment) proposed by Cankaya et al., (2016) and Tufekci et al., (2016), the awareness and preparedness level of the community is revealed to be an indispensable parameter with a great effect on tsunami risk. According to the results obtained from those studies, it becomes important that the awareness and preparedness parameter (n) must be analyzed by considering their interaction and all related components. While increasing awareness can be achieved, vulnerability and risk will be reduced. In this study the components of awareness and preparedness parameter (n) is analyzed in different categories by considering administrative, social, educational, economic and structural preparedness of the coastal communities. Hence the proposed awareness and preparedness parameter can properly be analyzed and further improvements can be achieved in vulnerability and risk analysis. Furthermore, the components of the awareness and preparedness parameter n, is widely investigated in global and local practices by using the method of categorization to determine different levels for different coastal metropolitan areas with different cultures and with different hazard perception. Moreover, consistency between the theoretical maximum and practical applications of parameter n is estimated, discussed and presented. In the applications mainly the Bakirkoy district of Istanbul is analyzed and the results are presented. Acknowledgements: Partial support by 603839 ASTARTE Project of EU, UDAPC-12-14 project of AFAD, Turkey, 213M534 projects of TUBITAK, Japan-Turkey Joint Research Project by JICA on earthquakes and tsunamis in Marmara Region in (JICA SATREPS - MarDiM Project), and Istanbul Metropolitan Municipality are acknowledged.

Development of Real-time Tsunami Inundation Forecast Using Ocean Bottom Tsunami Networks along the Japan Trench

NASA Astrophysics Data System (ADS)

Aoi, S.; Yamamoto, N.; Suzuki, W.; Hirata, K.; Nakamura, H.; Kunugi, T.; Kubo, T.; Maeda, T.

2015-12-01

In the 2011 Tohoku earthquake, in which huge tsunami claimed a great deal of lives, the initial tsunami forecast based on hypocenter information estimated using seismic data on land were greatly underestimated. From this lesson, NIED is now constructing S-net (Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench) which consists of 150 ocean bottom observatories with seismometers and pressure gauges (tsunamimeters) linked by fiber optic cables. To take full advantage of S-net, we develop a new methodology of real-time tsunami inundation forecast using ocean bottom observation data and construct a prototype system that implements the developed forecasting method for the Pacific coast of Chiba prefecture (Sotobo area). We employ a database-based approach because inundation is a strongly non-linear phenomenon and its calculation costs are rather heavy. We prepare tsunami scenario bank in advance, by constructing the possible tsunami sources, and calculating the tsunami waveforms at S-net stations, coastal tsunami heights and tsunami inundation on land. To calculate the inundation for target Sotobo area, we construct the 10-m-mesh precise elevation model with coastal structures. Based on the sensitivities analyses, we construct the tsunami scenario bank that efficiently covers possible tsunami scenarios affecting the Sotobo area. A real-time forecast is carried out by selecting several possible scenarios which can well explain real-time tsunami data observed at S-net from tsunami scenario bank. An advantage of our method is that tsunami inundations are estimated directly from the actual tsunami data without any source information, which may have large estimation errors. In addition to the forecast system, we develop Web services, APIs, and smartphone applications and brush them up through social experiments to provide the real-time tsunami observation and forecast information in easy way to understand toward urging people to evacuate.

Explanation of temporal clustering of tsunami sources using the epidemic-type aftershock sequence model

USGS Publications Warehouse

Geist, Eric L.

2014-01-01

Temporal clustering of tsunami sources is examined in terms of a branching process model. It previously was observed that there are more short interevent times between consecutive tsunami sources than expected from a stationary Poisson process. The epidemic‐type aftershock sequence (ETAS) branching process model is fitted to tsunami catalog events, using the earthquake magnitude of the causative event from the Centennial and Global Centroid Moment Tensor (CMT) catalogs and tsunami sizes above a completeness level as a mark to indicate that a tsunami was generated. The ETAS parameters are estimated using the maximum‐likelihood method. The interevent distribution associated with the ETAS model provides a better fit to the data than the Poisson model or other temporal clustering models. When tsunamigenic conditions (magnitude threshold, submarine location, dip‐slip mechanism) are applied to the Global CMT catalog, ETAS parameters are obtained that are consistent with those estimated from the tsunami catalog. In particular, the dip‐slip condition appears to result in a near zero magnitude effect for triggered tsunami sources. The overall consistency between results from the tsunami catalog and that from the earthquake catalog under tsunamigenic conditions indicates that ETAS models based on seismicity can provide the structure for understanding patterns of tsunami source occurrence. The fractional rate of triggered tsunami sources on a global basis is approximately 14%.

A Review of Methodologies on Vulnerability Assessment of Buildings to Tsunami Damage

NASA Astrophysics Data System (ADS)

Gunasekera, R.; Rosetto, T.; Tabuchi, S.; Suppasri, A.; Futami, T.; Scott, I.; Maegawa, H.

2012-04-01

The infrequency, suddenness and violence tsunamis has led to a lack of knowledge on tsunami and lack of data available for the calibration of numerical models particularly in relation to tsunami damage. Therefore, there are very few tsunami structural vulnerability studies available. Of the available literature, most of these started after the disastrous 2004 Indian Ocean event. Most of fragility curves have been developed in some areas struck by the 2004 tsunami, which are very different in architecture and engineering respect to the US, Japanese or European ones. This review aims to highlight the strengths and weaknesses of current knowledge on tsunami fragility by critically assessing several fragility curves based on post tsunami damage surveys in Chile, Japan (including initial findings of the March 2011 event), Samoa, Sri Lanka and Thailand. It is observed that there is no consensus on how to derive tsunami fragility curves. Most of the examined relationships are seen to relate to residential buildings, and, due to the location of recent tsunami occurrences, they mostly represent non-engineered buildings (i.e. all use data from Thailand, Sri Lanka, Samoa, or Sumatra), which limits their usefulness. In the absence of a good understanding of tsunami actions on buildings most existing fragility relationships adopt inundation depth as the hazard parameter in the vulnerability function, which does not account for the other components of onshore flow contributing to tsunami loads on buildings, such as flow velocity.

Modeling the mitigation effect of coastal forests on tsunami

NASA Astrophysics Data System (ADS)

Kh'ng, Xin Yi; Teh, Su Yean; Koh, Hock Lye

2017-08-01

As we have learned from the 26 Dec 2004 mega Andaman tsunami that killed 250, 000 lives worldwide, tsunami is a devastating natural disaster that can cause severe impacts including immense loss of human lives and extensive destruction of properties. The wave energy can be dissipated by the presence of coastal mangrove forests, which provide some degree of protection against tsunami waves. On the other hand, costly artificial structures such as reinforced walls can substantially diminish the aesthetic value and may cause environmental problems. To quantify the effectiveness of coastal forests in mitigating tsunami waves, an in-house 2-D model TUNA-RP is developed and used to quantify the reduction in wave heights and velocities due to the presence of coastal forests. The degree of reduction varies significantly depending on forest flow-resistant properties such as vegetation characteristics, forest density and forest width. The ability of coastal forest in reducing tsunami wave heights along the west coast of Penang Island is quantified by means of model simulations. Comparison between measured tsunami wave heights for the 2004 Andaman tsunami and 2-D TUNA-RP model simulated values demonstrated good agreement.

RESISTANCE OF EARTH BANK AGAINST TSUNAMI AND STRUCTURE OF DUG POOL FORMED BY TSUNAMI IN THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE

NASA Astrophysics Data System (ADS)

Tokida, Ken-Ichi; Tanimoto, Ryusuke

In the 2011 Off the Pacific Coast of Tohoku Earthquake, very huge damages of civil engineering structures etc. occurred by tsunami strikes along the rias coast and plane coast of the Pacific Ocean. For the urgent repair and the future reconstruction of these structures, the fundamental damage characteristics of these structures should be clarified by the field surveys from which effective lessons can be expected. In this paper, several important lessons on the resistance characteristics of 13 earth structures such as river dykes and sand banks which are obtained from the field surveys conducted by the authors are indicated. Because many dug pools were formed by the tsunami overflow at the backside of earth embankments and sea walls in this earthquake, the fundamental characteristics of the 10 dug pools are investigated thorough the field survey to estimate the effects of the dug pools quantitatively in the future. Furthermore through the field survey conducted at the representative site named Idoura, the scale and waterbed conditions of the natural canals and the strength characteristics of the river dykes and the base ground neighboring the natural canals are measured in detail and discussed. These fundamental lessons and data on the earth banks and dug pools will be able to be used to simulate the effects of the dug pools and to discuss the artificial canals as one of the hard countermeasures to reduce the tsunami height and/or force.

Our fingerprint in tsunami deposits - anthropogenic markers as a new tsunami identification tool

NASA Astrophysics Data System (ADS)

Bellanova, P.; Schwarzbauer, J.; Reicherter, K. R.; Jaffe, B. E.; Szczucinski, W.

2016-12-01

Several recent geochemical studies have focused on the use of inorganic indicators to evaluate a tsunami origin of sediment in the geologic record. However, tsunami transport not only particulate sedimentary material from marine to terrestrial areas (and vice versa), but also associated organic material. Thus, tsunami deposits may be characterized by organic-geochemical parameters. Recently increased attention has been given to the use of natural organic substances (biomarkers) to identify tsunami deposits. To date no studies have been made investigating anthropogenic organic indicators in recent tsunami deposits. Anthropogenic organic markers are more sensitive and reliable markers compared to other tracers due to their specific molecular structural properties and higher source specificity. In this study we evaluate whether anthropogenic substances are useful indicators for determining whether an area has been inundated by a tsunami. We chose the Sendai Plain and Sanemoura and Oppa Bays, Japan, as study sites because the destruction of infrastructure by flooding released environmental pollutants (e.g., fuels, fats, tarmac, plastics, heavy metals, etc.) contaminating large areas of the coastal zone during the 2011 Tohoku-oki tsunami. Organic compounds from the tsunami deposits are extracted from tsunami sediment and compared with the organic signature of unaffected pre-tsunami samples using gas chromatography-mass spectrometry (GS/MS) based analyses. For the anthropogenic markers, compounds such as soil derived pesticides (DDT), source specific PAHs, halogenated aromatics from industrial sources were detected and used to observe the inland extent and the impact of the Tohoku-oki tsunami on the coastal region around Sendai.

The 1946 Unimak Tsunami Earthquake Area: revised tectonic structure in reprocessed seismic images and a suspect near field tsunami source

USGS Publications Warehouse

Miller, John J.; von Huene, Roland E.; Ryan, Holly F.

2014-01-01

In 1946 at Unimak Pass, Alaska, a tsunami destroyed the lighthouse at Scotch Cap, Unimak Island, took 159 lives on the Hawaiian Islands, damaged island coastal facilities across the south Pacific, and destroyed a hut in Antarctica. The tsunami magnitude of 9.3 is comparable to the magnitude 9.1 tsunami that devastated the Tohoku coast of Japan in 2011. Both causative earthquake epicenters occurred in shallow reaches of the subduction zone. Contractile tectonism along the Alaska margin presumably generated the far-field tsunami by producing a seafloor elevation change. However, the Scotch Cap lighthouse was destroyed by a near-field tsunami that was probably generated by a coeval large undersea landslide, yet bathymetric surveys showed no fresh large landslide scar. We investigated this problem by reprocessing five seismic lines, presented here as high-resolution graphic images, both uninterpreted and interpreted, and available for the reader to download. In addition, the processed seismic data for each line are available for download as seismic industry-standard SEG-Y files. One line, processed through prestack depth migration, crosses a 10 × 15 kilometer and 800-meter-high hill presumed previously to be basement, but that instead is composed of stratified rock superimposed on the slope sediment. This image and multibeam bathymetry illustrate a slide block that could have sourced the 1946 near-field tsunami because it is positioned within a distance determined by the time between earthquake shaking and the tsunami arrival at Scotch Cap and is consistent with the local extent of high runup of 42 meters along the adjacent Alaskan coast. The Unimak/Scotch Cap margin is structurally similar to the 2011 Tohoku tsunamigenic margin where a large landslide at the trench, coeval with the Tohoku earthquake, has been documented. Further study can improve our understanding of tsunami sources along Alaska’s erosional margins.

Duration of Tsunami Generation Longer than Duration of Seismic Wave Generation in the 2011 Mw 9.0 Tohoku-Oki Earthquake

NASA Astrophysics Data System (ADS)

Fujihara, S.; Korenaga, M.; Kawaji, K.; Akiyama, S.

2013-12-01

We try to compare and evaluate the nature of tsunami generation and seismic wave generation in occurrence of the 2011 Tohoku-Oki earthquake (hereafter, called as TOH11), in terms of two type of moment rate functions, inferred from finite source imaging of tsunami waveforms and seismic waveforms. Since 1970's, the nature of "tsunami earthquakes" has been discussed in many researches (e.g. Kanamori, 1972; Kanamori and Kikuchi, 1993; Kikuchi and Kanamori, 1995; Ide et al., 1993; Satake, 1994) mostly based on analysis of seismic waveform data , in terms of the "slow" nature of tsunami earthquakes (e.g., the 1992 Nicaragura earthquake). Although TOH11 is not necessarily understood as a tsunami earthquake, TOH11 is one of historical earthquakes that simultaneously generated large seismic waves and tsunami. Also, TOH11 is one of earthquakes which was observed both by seismic observation network and tsunami observation network around the Japanese islands. Therefore, for the purpose of analyzing the nature of tsunami generation, we try to utilize tsunami waveform data as much as possible. In our previous studies of TOH11 (Fujihara et al., 2012a; Fujihara et al., 2012b), we inverted tsunami waveforms at GPS wave gauges of NOWPHAS to image the spatio-temporal slip distribution. The "temporal" nature of our tsunami source model is generally consistent with the other tsunami source models (e.g., Satake et al, 2013). For seismic waveform inversion based on 1-D structure, here we inverted broadband seismograms at GSN stations based on the teleseismic body-wave inversion scheme (Kikuchi and Kanamori, 2003). Also, for seismic waveform inversion considering the inhomogeneous internal structure, we inverted strong motion seismograms at K-NET and KiK-net stations, based on 3-D Green's functions (Fujihara et al., 2013a; Fujihara et al., 2013b). The gross "temporal" nature of our seismic source models are generally consistent with the other seismic source models (e.g., Yoshida et al., 2011; Ide at al., 2011; Yagi and Fukahata, 2011; Suzuki et al., 2011). The comparison of two type of moment rate functions, inferred from finite source imaging of tsunami waveforms and seismic waveforms, suggested that there was the time period common to both seismic wave generation and tsunami generation followed by the time period unique to tsunami generation. At this point, we think that comparison of the absolute values of moment rates is not so meaningful between tsunami waveform inversion and seismic waveform inversion, because of general ambiguity of rigidity values of each subfault in the fault region (assuming the rigidity value of 30 GPa of Yoshida et al (2011)). Considering this, the normalized value of moment rate function was also evaluated and it does not change the general feature of two moment rate functions in terms of duration property. Furthermore, the results suggested that tsunami generation process apparently took more time than seismic wave generation process did. Tsunami can be generated even by "extra" motions resulting from many suggested abnormal mechanisms. These extra motions may be attribute to the relatively larger-scale tsunami generation than expected from the magnitude level from seismic ground motion, and attribute to the longer duration of tsunami generation process.

Preliminary analysis of the earthquake (MW 8.1) and tsunami of April 1, 2007, in the Solomon Islands, southwestern Pacific Ocean

USGS Publications Warehouse

Fisher, Michael A.; Geist, Eric L.; Sliter, Ray; Wong, Florence L.; Reiss, Carol; Mann, Dennis M.

2007-01-01

On April 1, 2007, a destructive earthquake (Mw 8.1) and tsunami struck the central Solomon Islands arc in the southwestern Pacific Ocean. The earthquake had a thrust-fault focal mechanism and occurred at shallow depth (between 15 km and 25 km) beneath the island arc. The combined effects of the earthquake and tsunami caused dozens of fatalities and thousands remain without shelter. We present a preliminary analysis of the Mw-8.1 earthquake and resulting tsunami. Multichannel seismic-reflection data collected during 1984 show the geologic structure of the arc's frontal prism within the earthquake's rupture zone. Modeling tsunami-wave propagation indicates that some of the islands are so close to the earthquake epicenter that they were hard hit by tsunami waves as soon as 5 min. after shaking began, allowing people scant time to react.

Deposits of the 1983 and 1993 tsunamis on the coast of Primorye

NASA Astrophysics Data System (ADS)

Ganzey, L. A.; Razjigaeva, N. G.; Nishimura, Yu.; Grebennikova, T. A.; Gorbunov, A. O.; Kaistrenko, V. M.; Naumov, Yu. A.; Lebedev, I. I.

2017-07-01

Deposits of the two strongest tsunamis of the 20th century have been found on the eastern coast of Primorye. The tsunamis had epicenters in the Sea of Japan west of the coast of Hokkaido. The distribution and preservation of deposits in bays of different geomorphological structure have been analyzed. The best defined sedimentary covers occur in the upper part of sections in low-lying areas of bay shores, where the wave runup was more than 3 m. The best preserved deposits have been observed in bays attributed to loworder streams. Variations of the structural composition of tsunami deposits formed by traction processes associated with the tsunamis have been analyzed depending on distance from the shoreline; the sources of material have been identified. Tsunami waves transported sand not only from beaches, ancient storm ridges, and terraces, but also from the underwater coastal slope; waves also grabbed material from estuarine lagoons and lakes located in the shore inundation zone. Deposits include marine diatoms with dominant sublittoral planktonic and benthic species, which suggests that the material was transported from a depth no more than 15 m. Deep-sea species of diatoms and their fragments have been encountered. Among freshwater diatoms are species with different ecological identities, indicating erosion and redeposition of material transported from various sources.

Long-term statistics of extreme tsunami height at Crescent City

NASA Astrophysics Data System (ADS)

Dong, Sheng; Zhai, Jinjin; Tao, Shanshan

2017-06-01

Historically, Crescent City is one of the most vulnerable communities impacted by tsunamis along the west coast of the United States, largely attributed to its offshore geography. Trans-ocean tsunamis usually produce large wave runup at Crescent Harbor resulting in catastrophic damages, property loss and human death. How to determine the return values of tsunami height using relatively short-term observation data is of great significance to assess the tsunami hazards and improve engineering design along the coast of Crescent City. In the present study, the extreme tsunami heights observed along the coast of Crescent City from 1938 to 2015 are fitted using six different probabilistic distributions, namely, the Gumbel distribution, the Weibull distribution, the maximum entropy distribution, the lognormal distribution, the generalized extreme value distribution and the generalized Pareto distribution. The maximum likelihood method is applied to estimate the parameters of all above distributions. Both Kolmogorov-Smirnov test and root mean square error method are utilized for goodness-of-fit test and the better fitting distribution is selected. Assuming that the occurrence frequency of tsunami in each year follows the Poisson distribution, the Poisson compound extreme value distribution can be used to fit the annual maximum tsunami amplitude, and then the point and interval estimations of return tsunami heights are calculated for structural design. The results show that the Poisson compound extreme value distribution fits tsunami heights very well and is suitable to determine the return tsunami heights for coastal disaster prevention.

Probabilistic tsunami hazard assessment in Greece for seismic sources along the segmented Hellenic Arc

NASA Astrophysics Data System (ADS)

Novikova, Tatyana; Babeyko, Andrey; Papadopoulos, Gerassimos

2017-04-01

Greece and adjacent coastal areas are characterized by a high population exposure to tsunami hazard. The Hellenic Arc is the most active geotectonic structure for the generation of earthquakes and tsunamis. We performed probabilistic tsunami hazard assessment for selected locations of Greek coastlines which are the forecasting points officially used in the tsunami warning operations by the Hellenic National Tsunami Warning Center and the NEAMTWS/IOC/UNESCO. In our analysis we considered seismic sources for tsunami generation along the western, central and eastern segments of the Hellenic Arc. We first created a synthetic catalog as long as 10,000 years for all the significant earthquakes with magnitudes in the range from 6.0 to 8.5, the real events being included in this catalog. For each event included in the synthetic catalog a tsunami was generated and propagated using Boussinesq model. The probability of occurrence for each event was determined by Gutenberg-Richter magnitude-frequency distribution. The results of our study are expressed as hazard curves and hazard maps. The hazard curves were obtained for the selected sites and present the annual probability of exceedance as a function of pick coastal tsunami amplitude. Hazard maps represent the distribution of peak coastal tsunami amplitudes corresponding to a fixed annual probability. In such forms our results can be easily compared to the ones obtained in other studies and further employed for the development of tsunami risk management plans. This research is a contribution to the EU-FP7 tsunami research project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe), grant agreement no: 603839, 2013-10-30.

Manifestations of the 15.11.2006 Kuril Tsunami Consequences on the Central Kuril Islands: the Reconstruction Events of the Destruction of Soil and Coastal Vegetation.

NASA Astrophysics Data System (ADS)

Levin, B.; Kopanina, A.; Ivelskaya, T.; Sasorova, E.

2007-12-01

The investigation of the Central Kuril Islands (Simushir, Urup, Ketoy) coast was performance by the field survey for the Institute of Marine Geology and Geophysics FEB RAS (Yuzhno-Sakhalinsk) on the vessel "Iskatel-4" to be able find different deposits of the devastating tsunami waves influence on soil and vegetation. There were average run-up heights and inundation areas (tsunami flooding zones): h=6-9 m and 40-60 m (Ketoy); h=7-19 m and 80-300 m (Simushir). The field observation showed destruction of the soil layer. The estimation of water stream velocity for the hydraulic destruction of rocks enabled to receive velocity average mean for the water stream during tsunami dynamic inundation which may be in interval of velocities near 30 -50 m/sec. Field observations of coastal plants in tsunami inundation zones on Urup, Simushir and Ketoy Islands enabled us to recognize the character of destructive influence of tsunami waves to plant structure and essential signs of micro-phytocenoses for ecotopes at different distances from the coastline. Various plant species and vital morphes were found to indicate different reaction on sea waves. The investigation results showed that selected plant species demonstrate the strong response to tsunami wave inundation. We found that the most sensitive species to mechanical and physical- chemical tsunami impact are: Pinus pumila (Pall.) Regel and Phyllodoce aleutica (Spreng.) A. Heller. The character of plant damage shows in breaking of skeletal axes, infringement of root systems, and leaf dying. These findings allow us to use the species as effective indicators of tsunami flooding zone and estimation of tsunami run-up heights. Fulfilled analyzes let us to reconstruct possible events when tsunami hits to coast with specific shore morphology. The wave front at the slightly sloping coast (from coastline to first terrace) is characterized by uniform growth of water level when water moves away soil material (no more 2-3 cm) and micro- phytocenoses is maintaining the stability. During impact to steep dune slopes, tsunami wave generates violent horizontal streams which hit to sea-bank with velocities in order to 30m/sec and lead to considerable destructions of soil layer on the depth 30-35cm and structure damage of vegetation.

Vulnerability of the Built Environment to Tsunamis - an Overview of Where We Are in 2012

NASA Astrophysics Data System (ADS)

Petroff, C. M.

2012-12-01

The last twenty years have seen great strides in the understanding and prediction of tsunami behavior. Though study of these disasters has always been motivated by the need to reduce casualties and damage, early work focused primarily on predicting magnitude, propagation and inundation from tsunami waves. Investigations have expanded to include a burgeoning field concentrated on the landward effects of tsunamis on communities: examining building and infrastructure vulnerability, assessing the probabilities of varying levels of damage and applying these findings to planning of land-use, development, evacuation and response. Catastrophic events of the last decade in the Indian Ocean and Japan have brought these issues to the fore and raise the question: Where are we in our understanding of vulnerability to tsunamis? What have we learned? What are the lessons that the most recent events teach us? This overview summarizes recent investigations of the vulnerability of engineered structures to damage from tsunamis - from individual buildings of various uses to larger facilities and structural systems. Examples are provided of both successes and failures in design for tsunami resistance. Vulnerability of critical infrastructure and lifelines is discussed in the context of tsunamis in Sumatra, Chile and Japan. This includes the ability of critical systems to function during and immediately after a disaster as well as the short and long term resilience of utilities, services and coastal facilities after tsunamis. Recent work on probabilistic prediction of damage and development of fragility functions is summarized for the Chile 2010 and Japan 2011 tsunamis. Finally, a commentary is presented on building vulnerability issues as they relate to land use planning, building design and codes and vertical evacuation planning.; Three views of the Oya Train Station in Miyagi Prefecture: Prior to (top), two months after (middle), and one year after (bottom) the March 11, 2011 Tohoku Japan tsunami. The top view shows the rail line, shops, residences, coastal vegetation, tourist beach and coastal slope protection. All these were damaged or destroyed in the tsunami. One year after, a sand bag barrier had been installed inland of remaining low profile shore protection at Oya Kaigan. Rail lines had not been replaced and the station building remained closed. The area remained evacuated. Power line installation and road repairs were complete. (top photo courtesy F. Imamura)

Stakeholder-driven geospatial modeling for assessing tsunami vertical-evacuation strategies in the U.S. Pacific Northwest

NASA Astrophysics Data System (ADS)

Wood, N. J.; Schmidtlein, M.; Schelling, J.; Jones, J.; Ng, P.

2012-12-01

Recent tsunami disasters, such as the 2010 Chilean and 2011 Tohoku events, demonstrate the significant life loss that can occur from tsunamis. Many coastal communities in the world are threatened by near-field tsunami hazards that may inundate low-lying areas only minutes after a tsunami begins. Geospatial integration of demographic data and hazard zones has identified potential impacts on populations in communities susceptible to near-field tsunami threats. Pedestrian-evacuation models build on these geospatial analyses to determine if individuals in tsunami-prone areas will have sufficient time to reach high ground before tsunami-wave arrival. Areas where successful evacuations are unlikely may warrant vertical-evacuation (VE) strategies, such as berms or structures designed to aid evacuation. The decision of whether and where VE strategies are warranted is complex. Such decisions require an interdisciplinary understanding of tsunami hazards, land cover conditions, demography, community vulnerability, pedestrian-evacuation models, land-use and emergency-management policy, and decision science. Engagement with the at-risk population and local emergency managers in VE planning discussions is critical because resulting strategies include permanent structures within a community and their local ownership helps ensure long-term success. We present a summary of an interdisciplinary approach to assess VE options in communities along the southwest Washington coast (U.S.A.) that are threatened by near-field tsunami hazards generated by Cascadia subduction zone earthquakes. Pedestrian-evacuation models based on an anisotropic approach that uses path-distance algorithms were merged with population data to forecast the distribution of at-risk individuals within several communities as a function of travel time to safe locations. A series of community-based workshops helped identify potential VE options in these communities, collectively known as "Project Safe Haven" at the State of Washington Emergency Management Division. Models of the influence of stakeholder-driven VE options identified changes in the type and distribution of at-risk individuals. Insights from VE use and performance as an aid to evacuations from the 2011 Tohoku tsunami helped to inform the meetings and the analysis. We developed geospatial tools to automate parts of the pedestrian-evacuation models to support the iterative process of developing VE options and forecasting changes in population exposure. Our summary presents the interdisciplinary effort to forecast population impacts from near-field tsunami threats and to develop effective VE strategies to minimize fatalities in future events.

Near-Field Population Response During the 2 April 2007 Solomon Islands Tsunami

NASA Astrophysics Data System (ADS)

McAdoo, B. G.; Moore, A. L.; Baumwoll, J.

2007-12-01

When the magnitude 8.1 earthquake and subsequent tsunami hit the Solomon Islands on 2 April 2007 it killed 52 people. On Ghizo Island, home of the capital of the Western Province, Gizo, waves approaching 4 m in height inundated the south coast villages. Eyewitness accounts supported by geologic data from the offshore coral reef and sediment deposited on land suggest a wave that came in as the shaking stopped as a rapidly-rising tide rather than a turbulent bore- vehicles and houses were floated inland with very little damage. Those that survived in villages affected by the tsunami had indigenous knowledge of prior events, whereas immigrant populations died in higher proportions. While buoy-based early warning systems are necessary to mitigate the effects of teletsunamis, they would have done little good in this near-field environment. In Pailongge, a village of 76 indigenous Solomon Islanders on Ghizo's south coast, there were no deaths. Village elders directed the people inland following the shaking and the almost immediate withdrawal of water from the lagoon, and heads of household made sure that children were accounted for and evacuated. Of the 366 Gilbertese living in Titiana, however, 13 people died, 8 of which were children who were exploring the emptied lagoon. A large proportion of the dead were children (24) as they were likely too weak to swim against the non-bore flow. The Gilbertese migrated from Kiribati in the 1950"s, and had not experienced a major earthquake and tsunami, hence had no cultural memory. In the case of the Solomon Islands tsunami, as was the case in the 2004 Indian Ocean tsunami, indigenous knowledge served the people in the near-field well. In the case of the Indian Ocean where there was 10-20 minutes separation between the time the shaking began and the waves arrived, the combination of an in-place plan and a suitable physical geography allowed the population of Simeulue Island and the Moken people of Thailand to escape before the waves hit. In the Solomons, there was less than 3 minutes separation time, and the populations with indigenous knowledge were able to save themselves. Mitigation strategies for those that live adjacent to tsunamigenic subduction zones must include a community-based disaster management plan to educate a variety of populations with different cultural knowledges. This education can be in concert with development of an basin-wide early warning system.

Analysis of Tsunami Evacuation Issues Using Agent Based Modeling. A Case Study of the 2011 Tohoku Tsunami in Yuriage, Natori.

NASA Astrophysics Data System (ADS)

Mas, E.; Takagi, H.; Adriano, B.; Hayashi, S.; Koshimura, S.

2014-12-01

The 2011 Great East Japan earthquake and tsunami reminded that nature can exceed structural countermeasures like seawalls, breakwaters or tsunami gates. In such situations it is a challenging task for people to find nearby haven. This event, as many others before, confirmed the importance of early evacuation, tsunami awareness and the need for developing much more resilient communities with effective evacuation plans. To support reconstruction activities and efforts on developing resilient communities in areas at risk, tsunami evacuation simulation can be applied to tsunami mitigation and evacuation planning. In this study, using the compiled information related to the evacuation behavior at Yuriage in Natori during the 2011 tsunami, we simulated the evacuation process and explored the reasons for the large number of fatalities in the area. It was found that residents did evacuate to nearby shelter areas, however after the tsunami warning was increased some evacuees decided to conduct a second step evacuation to a far inland shelter. Simulation results show the consequences of such decision and the outcomes when a second evacuation would not have been performed. The actual reported number of fatalities in the event and the results from simulation are compared to verify the model. The case study shows the contribution of tsunami evacuation models as tools to be applied for the analysis of evacuees' decisions and the related outcomes. In addition, future evacuation plans and activities for reconstruction process and urban planning can be supported by the results provided from this kind of tsunami evacuation models.

Multiscale Modelling of the 2011 Tohoku Tsunami with Fluidity: Coastal Inundation and Run-up.

NASA Astrophysics Data System (ADS)

Hill, J.; Martin-Short, R.; Piggott, M. D.; Candy, A. S.

2014-12-01

Tsunami-induced flooding represents one of the most dangerous natural hazards to coastal communities around the world, as exemplified by Tohoku tsunami of March 2011. In order to further understand this hazard and to design appropriate mitigation it is necessary to develop versatile, accurate software capable of simulating large scale tsunami propagation and interaction with coastal geomorphology on a local scale. One such software package is Fluidity, an open source, finite element, multiscale, code that is capable of solving the fully three dimensional Navier-Stokes equations on unstructured meshes. Such meshes are significantly better at representing complex coastline shapes than structured meshes and have the advantage of allowing variation in element size across a domain. Furthermore, Fluidity incorporates a novel wetting and drying algorithm, which enables accurate, efficient simulation of tsunami run-up over complex, multiscale, topography. Fluidity has previously been demonstrated to accurately simulate the 2011 Tohoku tsunami (Oishi et al 2013) , but its wetting and drying facility has not yet been tested on a geographical scale. This study makes use of Fluidity to simulate the 2011 Tohoku tsunami and its interaction with Japan's eastern shoreline, including coastal flooding. The results are validated against observations made by survey teams, aerial photographs and previous modelling efforts in order to evaluate Fluidity's current capabilities and suggest methods of future improvement. The code is shown to perform well at simulating flooding along the topographically complex Tohoku coast of Japan, with major deviations between model and observation arising mainly due to limitations imposed by bathymetry resolution, which could be improved in future. In theory, Fluidity is capable of full multiscale tsunami modelling, thus enabling researchers to understand both wave propagation across ocean basins and flooding of coastal landscapes down to interaction with individual defence structures. This makes the code an exciting candidate for use in future studies aiming to investigate tsunami risk elsewhere in the world. Oishi, Y. et al. Three-dimensional tsunami propagation simulations using an unstructured mesh finite element model. J. Geophys. Res. [Solid Earth] 118, 2998-3018 (2013).

Evaluation of tsunami risk in Heraklion city, Crete, Greece, by using GIS methods

NASA Astrophysics Data System (ADS)

Triantafyllou, Ioanna; Fokaefs, Anna; Novikova, Tatyana; Papadopoulos, Gerasimos A.; Vaitis, Michalis

2016-04-01

The Hellenic Arc is the most active seismotectonic structure in the Mediterranean region. The island of Crete occupies the central segment of the arc which is characterized by high seismic and tsunami activity. Several tsunamis generated by large earthquakes, volcanic eruptions and landslides were reported that hit the capital city of Heraklion in the historical past. We focus our tsunami risk study in the northern coastal area of Crete (ca. 6 km in length and 1 km in maximum width) which includes the western part of the city of Heraklion and a large part of the neighboring municipality of Gazi. The evaluation of tsunami risk included calculations and mapping with QGIS of (1) cost for repairing buildings after tsunami damage, (2) population exposed to tsunami attack, (3) optimum routes and times for evacuation. To calculate the cost for building reparation after a tsunami attack we have determined the tsunami inundation zone in the study area after numerical simulations for extreme tsunami scenarios. The geographical distribution of buildings per building block, obtained from the 2011 census data of the Hellenic Statistical Authority (EL.STAT) and satellite data, was mapped. By applying the SCHEMA Damage Tool we assessed the building vulnerability to tsunamis according to the types of buildings and their expected damage from the hydrodynamic impact. A set of official cost rates varying with the building types and the damage levels, following standards set by the state after the strong damaging earthquakes in Greece in 2014, was applied to calculate the cost of rebuilding or repairing buildings damaged by the tsunami. In the investigation of the population exposed to tsunami inundation we have used the interpolation method to smooth out the population geographical distribution per building block within the inundation zone. Then, the population distribution was correlated with tsunami hydrodynamic parameters in the inundation zone. The last approach of tsunami risk assessment refers to the selection of optimal routes and times needed for evacuation from certain points within the inundation zone to a number of shelters outside the zone. The three different approaches were evaluated as for their overall contribution in the development of a plan for the tsunami risk mitigation. This research is a contribution to the EU-FP7 tsunami research project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe), grant agreement no: 603839, 2013-10-30.

Integrated Historical Tsunami Event and Deposit Database

NASA Astrophysics Data System (ADS)

Dunbar, P. K.; McCullough, H. L.

2010-12-01

The National Geophysical Data Center (NGDC) provides integrated access to historical tsunami event, deposit, and proxy data. The NGDC tsunami archive initially listed tsunami sources and locations with observed tsunami effects. Tsunami frequency and intensity are important for understanding tsunami hazards. Unfortunately, tsunami recurrence intervals often exceed the historic record. As a result, NGDC expanded the archive to include the Global Tsunami Deposits Database (GTD_DB). Tsunami deposits are the physical evidence left behind when a tsunami impacts a shoreline or affects submarine sediments. Proxies include co-seismic subsidence, turbidite deposits, changes in biota following an influx of marine water in a freshwater environment, etc. By adding past tsunami data inferred from the geologic record, the GTD_DB extends the record of tsunamis backward in time. Although the best methods for identifying tsunami deposits and proxies in the geologic record remain under discussion, developing an overall picture of where tsunamis have affected coasts, calculating recurrence intervals, and approximating runup height and inundation distance provides a better estimate of a region’s true tsunami hazard. Tsunami deposit and proxy descriptions in the GTD_DB were compiled from published data found in journal articles, conference proceedings, theses, books, conference abstracts, posters, web sites, etc. The database now includes over 1,200 descriptions compiled from over 1,100 citations. Each record in the GTD_DB is linked to its bibliographic citation where more information on the deposit can be found. The GTD_DB includes data for over 50 variables such as: event description (e.g., 2010 Chile Tsunami), geologic time period, year, deposit location name, latitude, longitude, country, associated body of water, setting during the event (e.g., beach, lake, river, deep sea), upper and lower contacts, underlying and overlying material, etc. If known, the tsunami source mechanism (e.g., earthquake, landslide, volcanic eruption, asteroid impact) is also specified. Observations (grain size, sedimentary structure, bed thickness, number of layers, etc.) are stored along with the conclusions drawn from the evidence by the author (wave height, flow depth, flow velocity, number of waves, etc.). Geologic time periods in the GTD_DB range from Precambrian to Quaternary, but the majority (70%) are from the Quaternary period. This period includes events such as: the 2004 Indian Ocean tsunami, the Cascadia subduction zone earthquakes and tsunamis, the 1755 Lisbon tsunami, the A.D. 79 Vesuvius tsunami, the 3500 BP Santorini caldera collapse and tsunami, and the 7000 BP Storegga landslide-generated tsunami. Prior to the Quaternary period, the majority of the paleotsunamis are due to impact events such as: the Tertiary Chesapeake Bay Bolide, Cretaceous-Tertiary (K/T) Boundary, Cretaceous Manson, and Devonian Alamo. The tsunami deposits are integrated with the historical tsunami event database where applicable. For example, users can search for articles describing deposits related to the 1755 Lisbon tsunami and view those records, as well as link to the related historic event record. The data and information may be viewed using tools designed to extract and display data (selection forms, Web Map Services, and Web Feature Services).

Change in the health of tsunami-exposed mothers three years after the natural disaster.

PubMed

Wickrama, Thulitha; Ketring, Scott A

2012-05-01

Women's experiences with secondary stressors resulting from natural disasters, such as increased economic insecurity, expanded caregiving responsibilities and disrupted family life, may contribute to women's mental and physical health problems. The present study investigates change and stability in post-tsunami depressive symptoms and perceived physical health of tsunami-exposed mothers over three and a half years. Using data from 160 tsunami-affected mothers, the present study uses structural equation modelling to investigate (1) change, stability, cross-lagged reciprocal influences of mental and physical health and (2) the meditation effect of negative life events on the relationship between tsunami exposure and post-tsunami depressive symptoms and perceived physical health of tsunami-exposed mothers from 2005 to 2008. Tsunami exposure contributed to depressive symptoms among mothers independently of pre-tsunami family adversities. Average depressive symptoms showed a decline whereas poor physical health showed an increase over this period. The results also revealed an interrelated health process between depression and physical health over time. Continuity of health problems were mediated by secondary stressors that also exerted an additive effect on later health problems. Post-disaster intervention and recovery programmes should focus not only on mothers' exposure to natural disasters, but also their pre- and post-natural disaster adversities. They should reach disaster-exposed mothers directly and have an integrated health approach to disrupt continuities of health problems.

The relationship between psychiatric morbidity and quality of life: interview study of Norwegian tsunami survivors 2 and 6 years post-disaster.

PubMed

Hussain, Ajmal; Nygaard, Egil; Siqveland, Johan; Heir, Trond

2016-05-31

The study investigated the impact of psychiatric disorders on Quality of Life (QOL) cross-sectionally and longitudinally in a group of Norwegian tourists severely exposed to the 2004 tsunami. Sixty-two adult Norwegian tsunami survivors were interviewed face to face 2 years post-tsunami (T1) and 58 were interviewed again by telephone 6 years post-tsunami (T2). The majority (81 %) reported direct exposure to the waves, and 14 participants (23 %) lost a close family member in the tsunami. Psychiatric morbidity was measured by structured clinical interviews and QOL was assessed with WHO's Quality of Life-Bref scale. Multiple linear regression analyses were performed to assess the independent effects of psychiatric disorders on QOL 2 and 6 years after the tsunami. Psychiatric disorders, especially depression, but also PTSD and other anxiety disorders, were associated with reduced QOL. Psychiatric disorders were more strongly related to QOL at 6 years after the tsunami than at 2 years. Psychiatric disorders, and especially depression, is related to reduced QOL in a disaster exposed population. Post-disaster psychiatric disorders, such as PTSD and especially depression, should be addressed properly in the aftermath of disasters.

Structure and Fabrication of a Microscale Flow-Rate/Skin Friction Sensor

NASA Technical Reports Server (NTRS)

Chandrasekharan, Vijay (Inventor); Sells, Jeremy (Inventor); Sheplak, Mark (Inventor); Arnold, David P. (Inventor)

2014-01-01

A floating element shear sensor and method for fabricating the same are provided. According to an embodiment, a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor is provided that can achieve time-resolved turbulence measurement. In one embodiment, a differential capacitive transduction scheme is used for shear stress measurement. The floating element structure for the differential capacitive transduction scheme incorporates inter digitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection.

New Science Applications Within the U.S. National Tsunami Hazard Mitigation Program

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Eble, M. C.; Forson, C. K.; Horrillo, J. J.; Nicolsky, D.

2017-12-01

The U.S. National Tsunami Hazard Mitigation Program (NTHMP) is a collaborative State and Federal program which supports consistent and cost effective tsunami preparedness and mitigation activities at a community level. The NTHMP is developing a new five-year Strategic Plan based on the 2017 Tsunami Warning, Education, and Research Act as well as recommendations the 2017 NTHMP External Review Panel. Many NTHMP activities are based on the best available scientific methods through the NTHMP Mapping and Modeling Subcommittee (MMS). The primary activities for the MMS member States are to characterize significant tsunami sources, numerically model those sources, and create tsunami inundation maps for evacuation planning. This work remains a focus for many unmapped coastlines. With the lessons learned from the 2004 Indian Ocean and 2011 Tohoku Japan tsunamis, where both immediate risks and long-term recovery issues where recognized, the NTHMP MMS is expanding efforts into other areas that address community resilience. Tsunami evacuation modeling based on both pedestrian and vehicular modes of transportation are being developed by NTHMP States. Products include tools for the public to create personal evacuation maps. New tsunami response planning tools are being developed for both maritime and coastal communities. Maritime planning includes tsunami current-hazard maps for in-harbor and offshore response activities. Multi-tiered tsunami evacuation plans are being developed in some states to address local- versus distant-source tsunamis, as well as real-time evacuation plans, or "playbooks," for distant-source tsunamis forecasted to be less than the worst-case flood event. Products to assist community mitigation and recovery are being developed at a State level. Harbor Improvement Reports, which evaluate the impacts of currents, sediment, and debris on harbor infrastructure, include direct mitigation activities for Local Hazard Mitigation Plans. Building code updates in the five Pacific states will include new sections on tsunami load analysis of structures, and require Tsunami Design Zones based on probabilistic analyses. Guidance for community recovery planning has also been initiated. These new projects are being piloted by some States and will help create guidance for other States in the future.

Geological Evidences for a Large Tsunami Generated by the 7.3 ka Kikai Caldera Eruption, Southern Japan

NASA Astrophysics Data System (ADS)

Yamada, M.; Fujino, S.; Satake, K.

2017-12-01

The 7.3 ka eruption of Kikai volcano, southern Kyushu, Japan, is one of the largest caldera-forming eruption in the world. Given that a huge caldera was formed in shallow sea area during the eruption, a tsunami must have been generated by a sea-level change associated. Pyroclastic flow and tsunami deposits by the eruption have been studied around the caldera, but they are not enough to evaluate the tsunami size. The goal of this study is to unravel sizes of tsunami and triggering caldera collapse by numerical simulations based on a widely-distributed tsunami deposit associated with the eruption. In this presentation, we will provide an initial data on distribution of the 7.3 ka tsunami deposit contained in sediment cores taken at three coastal lowlands in Wakayama, Tokushima, and Oita prefectures (560 km, 520 km, and 310 km north-east from the caldera, respectively). A volcanic ash from the eruption (Kikai Akahoya tephra: K-Ah) is evident in organic-rich muddy sedimentary sequence in all sediment cores. Up to 6-cm-thick sand layer, characterized by a grading structure and sharp bed boundary with lower mud, is observed immediately beneath the K-Ah tephra in all study sites. These sedimentary characteristics and broad distribution indicate that the sand layer was most likely deposited by a tsunami which can propagate to a wide area, but not by a local storm surge. Furthermore, the stratigraphic relationship implies that the study sites must have been inundated by the tsunami prior to the ash fall. A sand layer is also evident within the K-Ah tephra layer, suggesting that the sand layer was probably formed by a subsequent tsunami wave during the ash fall. These geological evidences for the 7.3 ka tsunami inundation will contribute to a better understanding of the caldera collapse and the resultant tsunami, but also of the tsunami generating system in the eruptive process.

Probabilistic Tsunami Hazard Analysis

NASA Astrophysics Data System (ADS)

Thio, H. K.; Ichinose, G. A.; Somerville, P. G.; Polet, J.

2006-12-01

The recent tsunami disaster caused by the 2004 Sumatra-Andaman earthquake has focused our attention to the hazard posed by large earthquakes that occur under water, in particular subduction zone earthquakes, and the tsunamis that they generate. Even though these kinds of events are rare, the very large loss of life and material destruction caused by this earthquake warrant a significant effort towards the mitigation of the tsunami hazard. For ground motion hazard, Probabilistic Seismic Hazard Analysis (PSHA) has become a standard practice in the evaluation and mitigation of seismic hazard to populations in particular with respect to structures, infrastructure and lifelines. Its ability to condense the complexities and variability of seismic activity into a manageable set of parameters greatly facilitates the design of effective seismic resistant buildings but also the planning of infrastructure projects. Probabilistic Tsunami Hazard Analysis (PTHA) achieves the same goal for hazards posed by tsunami. There are great advantages of implementing such a method to evaluate the total risk (seismic and tsunami) to coastal communities. The method that we have developed is based on the traditional PSHA and therefore completely consistent with standard seismic practice. Because of the strong dependence of tsunami wave heights on bathymetry, we use a full waveform tsunami waveform computation in lieu of attenuation relations that are common in PSHA. By pre-computing and storing the tsunami waveforms at points along the coast generated for sets of subfaults that comprise larger earthquake faults, we can efficiently synthesize tsunami waveforms for any slip distribution on those faults by summing the individual subfault tsunami waveforms (weighted by their slip). This efficiency make it feasible to use Green's function summation in lieu of attenuation relations to provide very accurate estimates of tsunami height for probabilistic calculations, where one typically computes thousands of earthquake scenarios. We have carried out preliminary tsunami hazard calculations for different return periods for western North America and Hawaii based on thousands of earthquake scenarios around the Pacific rim and along the coast of North America. We will present tsunami hazard maps for several return periods and also discuss how to use these results for probabilistic inundation and runup mapping. Our knowledge of certain types of tsunami sources is very limited (e.g. submarine landslides), but a probabilistic framework for tsunami hazard evaluation can include even such sources and their uncertainties and present the overall hazard in a meaningful and consistent way.

Earthquake-triggered landslides along the Hyblean-Malta Escarpment (off Augusta, eastern Sicily, Italy) - assessment of the related tsunamigenic potential

NASA Astrophysics Data System (ADS)

Ausilia Paparo, Maria; Armigliato, Alberto; Pagnoni, Gianluca; Zaniboni, Filippo; Tinti, Stefano

2017-02-01

Eastern Sicily is affected by earthquakes and tsunamis of local and remote origin, which is known through numerous historical chronicles. Recent studies have put emphasis on the role of submarine landslides as the direct cause of the main local tsunamis, envisaging that earthquakes (in 1693 and 1908) did produce a tsunami, but also that they triggered mass failures that were able to generate an even larger tsunami. The debate is still open, and though no general consensus has been found among scientists so far, this research had the merit to attract attention on possible generation of tsunamis by landslides off Sicily. In this paper we investigate the tsunami potential of mass failures along one sector of the Hyblean-Malta Escarpment (HME). facing Augusta. The HME is the main offshore geological structure of the region running almost parallel to the coast, off eastern Sicily. Here, bottom morphology and slope steepness favour soil failures. In our work we study slope stability under seismic load along a number of HME transects by using the Minimun Lithostatic Deviation (MLD) method, which is based on the limit-equilibrium theory. The main goal is to identify sectors of the HME that could be unstable under the effect of realistic earthquakes. We estimate the possible landslide volume and use it as input for numerical codes to simulate the landslide motion and the consequent tsunami. This is an important step for the assessment of the tsunami hazard in eastern Sicily and for local tsunami mitigation policies. It is also important in view of tsunami warning system since it can help to identify the minimum earthquake magnitude capable of triggering destructive tsunamis induced by landslides, and therefore to set up appropriate knowledge-based criteria to launch alert to the population.

PTSD symptoms among tsunami exposed mothers in Sri Lanka: the role of disaster exposure, culturally specific coping strategies, and recovery efforts.

PubMed

Wickrama, Thulitha; Wickrama, K A S; Banford, Alyssa; Lambert, Jessica

2017-07-01

Women in Sri Lanka have been uniquely exposed to a complex and protracted set of stressors stemming from a civil war conflict spanning over 25 years and the tsunami which struck Southeast Asia in 2004. This study investigates coping strategies and their association with trauma-related symptoms of tsunami-exposed mothers in Sri Lanka at two time points. Data for this study come from surveys administered in two waves of data collection to investigate both mothers' and adolescent children's post-tsunami mental health in early 2005, three months after the tsunami struck, and again in 2008, three years later. Latent-variable structural equation modeling was used to test the study hypotheses among 160 tsunami-affected mothers in the Polhena village, Matara district, Sri Lanka. Among the various coping strategies examined, the use of cultural rituals as well as inner psychological strength was associated with lower levels of posttraumatic stress symptoms. In contrast, passive religious beliefs were associated with greater posttraumatic stress levels. The results of this study reveal the differential associations of various coping strategies including rituals used by mothers exposed to the tsunami in Sri Lanka and their posttraumatic stress symptom levels.

Tsunami and shelf resonance on the northern Chile coast

NASA Astrophysics Data System (ADS)

Cortés, Pablo; Catalán, Patricio A.; Aránguiz, Rafael; Bellotti, Giorgio

2017-09-01

This work presents the analysis of long waves resonance in two of the main cities along the northern coast of Chile, Arica, and Iquique, where a large tsunamigenic potential remains despite recent earthquakes. By combining a modal analysis solving the equation of free surface oscillations, with the analysis of background spectra derived from in situ measurements, the spatial and temporal structures of the modes are recovered. Comparison with spectra from three tsunamis of different characteristics shows that the modes found have been excited by past events. Moreover, the two locations show different response patterns. Arica is more sensitive to the characteristics of the tsunami source, whereas Iquique shows a smaller dependency and similar response for different tsunami events. Results are further compared with other methodologies with good agreement. These findings are relevant in characterizing the tsunami hazard in the area, and the methodology can be further extended to other regions along the Chilean coast.

Effects of fringing reefs on tsunami inundation: American Samoa

USGS Publications Warehouse

Gelfenbaum, G.; Apotsos, A.; Stevens, A.W.; Jaffe, B.

2011-01-01

A numerical model of tsunami inundation, Delft3D, which has been validated for the 29 September 2009 tsunami in Tutuila, American Samoa, is used to better understand the impact of fringing coral reefs and embayments on tsunami wave heights, inundation distances, and velocities. The inundation model is used to explore the general conditions under which fringing reefs act as coastal buffers against incoming tsunamis. Of particular interest is the response of tsunamis to reefs of varying widths, depths, and roughness, as well as the effects of channels incised in the reef and the focusing effect of embayments. Model simulations for conditions similar to Tutuila, yet simplified to be uniform in the alongshore, suggest that for narrow reefs, less than about 200 m wide, the shoaling owing to shallow water depths over the fringing reef dominates, inducing greater wave heights onshore under some conditions and farther inundation inland. As the reef width increases, wave dissipation through bottom friction begins to dominate and the reef causes the tsunami wave heights to decrease and the tsunami to inundate less far inland. A sensitivity analysis suggests that coral reef roughness is important in determining the manner in which a fringing reef affects tsunami inundation. Smooth reefs are more likely to increase the onshore velocity within the tsunami compared to rough reefs. A larger velocity will likely result in an increased impact of the tsunami on structures and buildings. Simulations developed to explore 2D coastal morphology show that incised channels similar to those found around Tutuila, as well as coastal embayments, also affect tsunami inundation, allowing larger waves to penetrate farther inland. The largest effect is found for channels located within embayments, and for embayments that narrow landward. These simulations suggest that embayments that narrow landward, such as Fagafue Bay on the north side of Tutuila, and that have an incised deep channel, can cause a significant increase in tsunami wave heights, inundation distances, and velocities. Wide embayments, similar in size to Massacre Bay, induce some tsunami amplification, but not as much as for the narrowing embayment.

Coastal Tsunami and Risk Assessment for Eastern Mediterranean Countries

NASA Astrophysics Data System (ADS)

Kentel, E.; Yavuz, C.

2017-12-01

Tsunamis are rarely experienced events that have enormous potential to cause large economic destruction on the critical infrastructures and facilities, social devastation due to mass casualty, and environmental adverse effects like erosion, accumulation and inundation. Especially for the past two decades, nations have encountered devastating tsunami events. The aim of this study is to investigate risks along the Mediterranean coastline due to probable tsunamis based on simulations using reliable historical data. In order to do this, 50 Critical Regions, CRs, (i.e. city centers, agricultural areas and summer villages) and 43 Critical Infrastructures, CIs, (i.e. airports, ports & marinas and industrial structures) are determined to perform people-centered risk assessment along Eastern Mediterranean region covering 7 countries. These countries include Turkey, Syria, Lebanon, Israel, Egypt, Cyprus, and Libya. Bathymetry of the region is given in Figure 1. In this study, NAMI-DANCE is used to carry out tsunami simulations. Source of a sample tsunami simulation and maximum wave propagation in the study area for this sample tsunami are given in Figures 2 and 3, respectively.Richter magnitude,, focal depth, time of occurrence in a day and season are considered as the independent parameters of the earthquake. Historical earthquakes are used to generate reliable probability distributions for these parameters. Monte Carlo (MC) Simulations are carried out to evaluate overall risks at the coastline. Inundation level, population density, number of passenger or employee, literacy rate, annually income level and existence of human are used in risk estimations. Within each MC simulation and for each grid in the study area, people-centered tsunami risk for each of the following elements at risk is calculated: i. City centers ii. Agricultural areas iii. Summer villages iv. Ports and marinas v. Airports vi. Industrial structures Risk levels at each grid along the shoreline are calculated based on the factors given above, grouped into low, medium and high risk, and used in generating the risk map. The risk map will be useful in prioritizing areas that require development of tsunami mitigation measures.

Tsunami Simulators in Physical Modelling Laboratories - From Concept to Proven Technique

NASA Astrophysics Data System (ADS)

Allsop, W.; Chandler, I.; Rossetto, T.; McGovern, D.; Petrone, C.; Robinson, D.

2016-12-01

Before 2004, there was little public awareness around Indian Ocean coasts of the potential size and effects of tsunami. Even in 2011, the scale and extent of devastation by the Japan East Coast Tsunami was unexpected. There were very few engineering tools to assess onshore impacts of tsunami, so no agreement on robust methods to predict forces on coastal defences, buildings or related infrastructure. Modelling generally used substantial simplifications of either solitary waves (far too short durations) or dam break (unrealistic and/or uncontrolled wave forms).This presentation will describe research from EPI-centre, HYDRALAB IV, URBANWAVES and CRUST projects over the last 10 years that have developed and refined pneumatic Tsunami Simulators for the hydraulic laboratory. These unique devices have been used to model generic elevated and N-wave tsunamis up to and over simple shorelines, and at example defences. They have reproduced full-duration tsunamis including the Mercator trace from 2004 at 1:50 scale. Engineering scale models subjected to those tsunamis have measured wave run-up on simple slopes, forces on idealised sea defences and pressures / forces on buildings. This presentation will describe how these pneumatic Tsunami Simulators work, demonstrate how they have generated tsunami waves longer than the facility within which they operate, and will highlight research results from the three generations of Tsunami Simulator. Of direct relevance to engineers and modellers will be measurements of wave run-up levels and comparison with theoretical predictions. Recent measurements of forces on individual buildings have been generalized by separate experiments on buildings (up to 4 rows) which show that the greatest forces can act on the landward (not seaward) buildings. Continuing research in the 70m long 4m wide Fast Flow Facility on tsunami defence structures have also measured forces on buildings in the lee of a failed defence wall.

Factors Affecting Household Adoption of an Evacuation Plan in American Samoa after the 2009 Earthquake and Tsunami

PubMed Central

Gregg, Chris E; Richards, Kasie; Sorensen, Barbara Vogt; Wang, Liang

2013-01-01

American Samoa is still recovering from the debilitating consequences of the September 29, 2009 tsunami. Little is known about current household preparedness in American Samoa for future earthquakes and tsunamis. Thus, this study sought to enumerate the number of households with an earthquake and tsunami evacuation plan and to identify predictors of having a household evacuation plan through a post-tsunami survey conducted in July 2011. Members of 300 households were interviewed in twelve villages spread across regions of the principle island of Tutuila. Multiple logistic regression showed that being male, having lived in one's home for < 30 years, and having a friend who suffered damage to his or her home during the 2009 tsunami event increased the likelihood of having a household evacuation plan. The prevalence of tsunami evacuation planning was 35% indicating that survivors might feel that preparation is not necessary given effective adaptive responses during the 2009 event. Results suggest that emergency planners and public health officials should continue with educational outreach to families to spread awareness around the importance of developing plans for future earthquakes and tsunamis to help mitigate human and structural loss from such natural disasters. Additional research is needed to better understand the linkages between pre-event planning and effective evacuation responses as were observed in the 2009 events. PMID:24349889

Factors affecting household adoption of an evacuation plan in American Samoa after the 2009 earthquake and tsunami.

PubMed

Apatu, Emma J I; Gregg, Chris E; Richards, Kasie; Sorensen, Barbara Vogt; Wang, Liang

2013-08-01

American Samoa is still recovering from the debilitating consequences of the September 29, 2009 tsunami. Little is known about current household preparedness in American Samoa for future earthquakes and tsunamis. Thus, this study sought to enumerate the number of households with an earthquake and tsunami evacuation plan and to identify predictors of having a household evacuation plan through a post-tsunami survey conducted in July 2011. Members of 300 households were interviewed in twelve villages spread across regions of the principle island of Tutuila. Multiple logistic regression showed that being male, having lived in one's home for < 30 years, and having a friend who suffered damage to his or her home during the 2009 tsunami event increased the likelihood of having a household evacuation plan. The prevalence of tsunami evacuation planning was 35% indicating that survivors might feel that preparation is not necessary given effective adaptive responses during the 2009 event. Results suggest that emergency planners and public health officials should continue with educational outreach to families to spread awareness around the importance of developing plans for future earthquakes and tsunamis to help mitigate human and structural loss from such natural disasters. Additional research is needed to better understand the linkages between pre-event planning and effective evacuation responses as were observed in the 2009 events.

Evaluation and Numerical Simulation of Tsunami for Coastal Nuclear Power Plants of India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Pavan K.; Singh, R.K.; Ghosh, A.K.

2006-07-01

Recent tsunami generated on December 26, 2004 due to Sumatra earthquake of magnitude 9.3 resulted in inundation at the various coastal sites of India. The site selection and design of Indian nuclear power plants demand the evaluation of run up and the structural barriers for the coastal plants: Besides it is also desirable to evaluate the early warning system for tsunami-genic earthquakes. The tsunamis originate from submarine faults, underwater volcanic activities, sub-aerial landslides impinging on the sea and submarine landslides. In case of a submarine earthquake-induced tsunami the wave is generated in the fluid domain due to displacement of themore » seabed. There are three phases of tsunami: generation, propagation, and run-up. Reactor Safety Division (RSD) of Bhabha Atomic Research Centre (BARC), Trombay has initiated computational simulation for all the three phases of tsunami source generation, its propagation and finally run up evaluation for the protection of public life, property and various industrial infrastructures located on the coastal regions of India. These studies could be effectively utilized for design and implementation of early warning system for coastal region of the country apart from catering to the needs of Indian nuclear installations. This paper presents some results of tsunami waves based on different analytical/numerical approaches with shallow water wave theory. (authors)« less

First tsunami gravity wave detection in ionospheric radio occultation data

DOE PAGES

Coïsson, Pierdavide; Lognonné, Philippe; Walwer, Damian; ...

2015-05-09

After the 11 March 2011 earthquake and tsunami off the coast of Tohoku, the ionospheric signature of the displacements induced in the overlying atmosphere has been observed by ground stations in various regions of the Pacific Ocean. We analyze here the data of radio occultation satellites, detecting the tsunami-driven gravity wave for the first time using a fully space-based ionospheric observation system. One satellite of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) recorded an occultation in the region above the tsunami 2.5 h after the earthquake. The ionosphere was sounded from top to bottom, thus providing themore » vertical structure of the gravity wave excited by the tsunami propagation, observed as oscillations of the ionospheric Total Electron Content (TEC). The observed vertical wavelength was about 50 km, with maximum amplitude exceeding 1 total electron content unit when the occultation reached 200 km height. We compared the observations with synthetic data obtained by summation of the tsunami-coupled gravity normal modes of the Earth/Ocean/atmosphere system, which models the associated motion of the ionosphere plasma. These results provide experimental constraints on the attenuation of the gravity wave with altitude due to atmosphere viscosity, improving the understanding of the propagation of tsunami-driven gravity waves in the upper atmosphere. They demonstrate that the amplitude of the tsunami can be estimated to within 20% by the recorded ionospheric data.« less

Multidimensional Approach for Tsunami Vulnerability Assessment: Framing the Territorial Impacts in Two Municipalities in Portugal.

PubMed

Tavares, Alexandre Oliveira; Barros, José Leandro; Santos, Angela

2017-04-01

This study presents a new multidimensional methodology for tsunami vulnerability assessment that combines the morphological, structural, social, and tax component of vulnerability. This new approach can be distinguished from previous methodologies that focused primarily on the evaluation of potentially affected buildings and did not use tsunami numerical modeling. The methodology was applied to the Figueira da Foz and Vila do Bispo municipalities in Portugal. For each area, the potential tsunami-inundated areas were calculated considering the 1755 Lisbon tsunami, which is the greatest disaster caused by natural hazards that ever occurred in Portugal. Furthermore, the four components of the vulnerability were calculated to obtain a composite vulnerability index. This methodology enables us to differentiate the two areas in their vulnerability, highlighting the characteristics of the territory components. This methodology can be a starting point for the creation of a local assessment framework at the municipal scale related to tsunami risk. In addition, the methodology is an important support for the different local stakeholders. © 2016 Society for Risk Analysis.

Topographic data acquisition in tsunami-prone coastal area using Unmanned Aerial Vehicle (UAV)

NASA Astrophysics Data System (ADS)

Marfai, M. A.; Sunarto; Khakim, N.; Cahyadi, A.; Rosaji, F. S. C.; Fatchurohman, H.; Wibowo, Y. A.

2018-04-01

The southern coastal area of Java Island is one of the nine seismic gaps prone to tsunamis. The entire coastline in one of the regencies, Gunungkidul, is exposed to the subduction zone in the Indian Ocean. Also, the growing tourism industries in the regency increase its vulnerability, which places most of its areas at high risk of tsunamis. The same case applies to Kukup, i.e., one of the most well-known beaches in Gunungkidul. Structurally shaped cliffs that surround it experience intensive wave erosion process, but it has very minimum access for evacuation routes. Since tsunami modeling is a very advanced analysis, it requires an accurate topographic data. Therefore, the research aimed to generate the topographic data of Kukup Beach as the baseline in tsunami risk reduction analysis and disaster management. It used aerial photograph data, which was acquired using Unmanned Aerial Vehicle (UAV). The results showed that the aerial photographs captured by drone had accurate elevation and spatial resolution. Therefore, they are applicable for tsunami modeling and disaster management.

A Possible Source Mechanism of the 1946 Unimak Alaska Far-Field Tsunami: Uplift of the Mid-Slope Terrace Above a Splay Fault Zone

NASA Astrophysics Data System (ADS)

von Huene, Roland; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter

2016-12-01

In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of "tsunami" earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

Wind Turbine Controller to Mitigate Structural Loads on a Floating Wind Turbine Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul A.; Peiffer, Antoine; Schlipf, David

This paper summarizes the control design work that was performed to optimize the controller of a wind turbine on the WindFloat structure. The WindFloat is a semi-submersible floating platform designed to be a support structure for a multi-megawatt power-generating wind turbine. A controller developed for a bottom-fixed wind turbine configuration was modified for use when the turbine is mounted on the WindFloat platform. This results in an efficient platform heel resonance mitigation scheme. In addition several control modules, designed with a coupled linear model, were added to the fixed-bottom baseline controller. The approach was tested in a fully coupled nonlinearmore » aero-hydroelastic simulation tool in which wind and wave disturbances were modeled. This testing yielded significant improvements in platform global performance and tower-base-bending loading.« less

The effect of compliant prisms on subduction zone earthquakes and tsunamis

NASA Astrophysics Data System (ADS)

Lotto, Gabriel C.; Dunham, Eric M.; Jeppson, Tamara N.; Tobin, Harold J.

2017-01-01

Earthquakes generate tsunamis by coseismically deforming the seafloor, and that deformation is largely controlled by the shallow rupture process. Therefore, in order to better understand how earthquakes generate tsunamis, one must consider the material structure and frictional properties of the shallowest part of the subduction zone, where ruptures often encounter compliant sedimentary prisms. Compliant prisms have been associated with enhanced shallow slip, seafloor deformation, and tsunami heights, particularly in the context of tsunami earthquakes. To rigorously quantify the role compliant prisms play in generating tsunamis, we perform a series of numerical simulations that directly couple dynamic rupture on a dipping thrust fault to the elastodynamic response of the Earth and the acoustic response of the ocean. Gravity is included in our simulations in the context of a linearized Eulerian description of the ocean, which allows us to model tsunami generation and propagation, including dispersion and related nonhydrostatic effects. Our simulations span a three-dimensional parameter space of prism size, prism compliance, and sub-prism friction - specifically, the rate-and-state parameter b - a that determines velocity-weakening or velocity-strengthening behavior. We find that compliant prisms generally slow rupture velocity and, for larger prisms, generate tsunamis more efficiently than subduction zones without prisms. In most but not all cases, larger, more compliant prisms cause greater amounts of shallow slip and larger tsunamis. Furthermore, shallow friction is also quite important in determining overall slip; increasing sub-prism b - a enhances slip everywhere along the fault. Counterintuitively, we find that in simulations with large prisms and velocity-strengthening friction at the base of the prism, increasing prism compliance reduces rather than enhances shallow slip and tsunami wave height.

Sedimentary deposits study of the 2006 Java tsunami, in Pangandaran, West Java (preliminary result)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maemunah, Imun, E-mail: imun-m2001@yahoo.com; Institute Technology of Bandung; Suparka, Emmy, E-mail: emmy@gc.itb.ac.id

The 2006 Java Earthquake (Mw 7.2) has generated a tsunami that reached Pangandaran coastal plain with 9.7 m above sea level height of wave. In 2014 we examined the tsunami deposit exposed in shallow trenches along a∼300 m at 5 transect from shoreline to inland on Karapyak and Madasari, Pangandaran. We documented stratigraphically and sedimentologically, the characteristics of Java Tsunami deposit on Karapyak and Madasari and compared both sediments. In local farmland a moderately-sorted, brown soil is buried by a poorly-sorted, grey, medium-grained sand-sheet. The tsunami deposit was distinguished from the underlying soil by a pronounced increase in grain size that becomesmore » finner upwards and landwards. Decreasing concentration of coarse size particles with distance toward inland are in agreement with grain size analysis. The thickest tsunami deposit is about 25 cm found at 84 m from shoreline in Madasari and about 15 cm found at 80 m from shoreline in Karapyak. The thickness of tsunami deposits in some transect become thinner landward but in some other transect lack a consistent suggested strongly affected by local topography. Tsunami deposits at Karapyak and Madasari show many similarities. Both deposits consist of coarse sand that sharply overlies a finer sandy soil. The presence mud drapes and other sedimentary structure like graded bedding, massive beds, mud clasts in many locations shows a dynamics process of tsunami waves. The imbrication coarse and shell fragments of the 2006 Java, tsunami deposits also provide information about the curent direction, allowing us to distinguish run up deposits from backwash deposits.« less

Modeling for the SAFRR Tsunami Scenario-generation, propagation, inundation, and currents in ports and harbors: Chapter D in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

USGS Publications Warehouse

,

2013-01-01

This U.S. Geological Survey (USGS) Open-File report presents a compilation of tsunami modeling studies for the Science Application for Risk Reduction (SAFRR) tsunami scenario. These modeling studies are based on an earthquake source specified by the SAFRR tsunami source working group (Kirby and others, 2013). The modeling studies in this report are organized into three groups. The first group relates to tsunami generation. The effects that source discretization and horizontal displacement have on tsunami initial conditions are examined in section 1 (Whitmore and others). In section 2 (Ryan and others), dynamic earthquake rupture models are explored in modeling tsunami generation. These models calculate slip distribution and vertical displacement of the seafloor as a result of realistic fault friction, physical properties of rocks surrounding the fault, and dynamic stresses resolved on the fault. The second group of papers relates to tsunami propagation and inundation modeling. Section 3 (Thio) presents a modeling study for the entire California coast that includes runup and inundation modeling where there is significant exposure and estimates of maximum velocity and momentum flux at the shoreline. In section 4 (Borrero and others), modeling of tsunami propagation and high-resolution inundation of critical locations in southern California is performed using the National Oceanic and Atmospheric Administration’s (NOAA) Method of Splitting Tsunami (MOST) model and NOAA’s Community Model Interface for Tsunamis (ComMIT) modeling tool. Adjustments to the inundation line owing to fine-scale structures such as levees are described in section 5 (Wilson). The third group of papers relates to modeling of hydrodynamics in ports and harbors. Section 6 (Nicolsky and Suleimani) presents results of the model used at the Alaska Earthquake Information Center for the Ports of Los Angeles and Long Beach, as well as synthetic time series of the modeled tsunami for other selected locales in southern California. Importantly, section 6 provides a comparison of the effect of including horizontal displacements at the source described in section 1 and differences in bottom friction on wave heights and inundation in the Ports of Los Angeles and Long Beach. Modeling described in section 7 (Lynett and Son) uses a higher order physical model to determine variations of currents during the tsunami and complex flow structures such as jets and eddies. Section 7 also uses sediment transport models to estimate scour and deposition of sediment in ports and harbors—a significant effect that was observed in southern California following the 2011 Tohoku tsunami. Together, all of the sections in this report form the basis for damage, impact, and emergency preparedness aspects of the SAFRR tsunami scenario. Three sections of this report independently calculate wave height and inundation results using the source specified by Kirby and others (2013). Refer to figure 29 in section 3, figure 52 in section 4, and figure 62 in section 6. All of these results are relative to a mean high water (MHW) vertical datum. Slight differences in the results are observed in East Basin of the Port of Los Angeles, Alamitos Bay, and the Seal Beach National Wildlife Refuge. However, given that these three modeling efforts involved different implementations of the source, different numerical wave propagation and runup models, and slight differences in the digital elevation models (DEMs), the similarity among the results is remarkable.

Earthquake- and tsunami-induced ionospheric disturbances detected by GPS total electron content observation

NASA Astrophysics Data System (ADS)

Tsugawa, T.; Nishioka, M.; Matsumura, M.; Shinagawa, H.; Maruyama, T.; Ogawa, T.; Saito, A.; Otsuka, Y.; Nagatsuma, T.; Murata, T.

2012-12-01

Ionospheric disturbances induced by the 2011 Tohoku earthquake and tsunami were studied by the high-resolution GPS total electron content (TEC) observation in Japan and in the world. The initial ionospheric disturbance appeared as sudden depletions by about 6 TEC unit (20%) about seven minutes after the earthquake onset, near the epicenter. From 06:00UT to 06:15UT, circular waves with short propagation distance propagated in the radial direction in the propagation velocity of 3,457, 783, 423 m/s for the first, second, third peak, respectively. Following these waves, concentric waves with long propagation distance appeared to propagate at the velocity of 138-288 m/s. In the vicinity of the epicenter, shortperiod oscillations with period of about 4 minutes were observed after 06:00 UT for 3 hours or more. We focus on the the circular and concentric waves in this paper. The circular or concentric structures indicate that these ionospheric disturbances had a point source. The center of these structures, termed as "ionospheric epicenter", was located around 37.5 deg N of latitude and 144.0 deg E of longitude, 170 km far from the epicenter to the southeast direction, and corresponded to the tsunami source. Comparing to the results of a numerical simulation using non-hydrostatic compressible atmosphere-ionosphere model, the first peak of circular wave would be caused by the acoustic waves generated from the propagating Rayleigh wave. The second and third waves would be caused by atmospheric gravity waves excited in the lower ionosphere due to the acoustic wave propagations from the tsunami source. The fourth and following waves are considered to be caused by the atmospheric gravity waves induced by the wavefronts of traveling tsunami. Long-propagation of these TEC disturbances were studied also using high-resolution GPS-TEC data in North America and Europe. Medium-scale wave structures with wavelengths of several 100 km appeared in the west part of North America at the almost same time as the tsunami arrival. On the other hand, no remarkable wave structure was observed in Europe. We will introduce these observational results and discuss about the generation and propagation mechanisms of the ionospheric disturbances induced by the earthquake and tsunami.

Development of High Precision Tsunami Runup Calculation Method Coupled with Structure Analysis

NASA Astrophysics Data System (ADS)

Arikawa, Taro; Seki, Katsumi; Chida, Yu; Takagawa, Tomohiro; Shimosako, Kenichiro

2017-04-01

The 2011 Great East Japan Earthquake (GEJE) has shown that tsunami disasters are not limited to inundation damage in a specified region, but may destroy a wide area, causing a major disaster. Evaluating standing land structures and damage to them requires highly precise evaluation of three-dimensional fluid motion - an expensive process. Our research goals were thus to develop a coupling STOC-CADMAS (Arikawa and Tomita, 2016) coupling with the structure analysis (Arikawa et. al., 2009) to efficiently calculate all stages from tsunami source to runup including the deformation of structures and to verify their applicability. We also investigated the stability of breakwaters at Kamaishi Bay. Fig. 1 shows the whole of this calculation system. The STOC-ML simulator approximates pressure by hydrostatic pressure and calculates the wave profiles based on an equation of continuity, thereby lowering calculation cost, primarily calculating from a e epi center to the shallow region. As a simulator, STOC-IC solves pressure based on a Poisson equation to account for a shallower, more complex topography, but reduces computation cost slightly to calculate the area near a port by setting the water surface based on an equation of continuity. CS3D also solves a Navier-Stokes equation and sets the water surface by VOF to deal with the runup area, with its complex surfaces of overflows and bores. STR solves the structure analysis including the geo analysis based on the Biot's formula. By coupling these, it efficiently calculates the tsunami profile from the propagation to the inundation. The numerical results compared with the physical experiments done by Arikawa et. al.,2012. It was good agreement with the experimental ones. Finally, the system applied to the local situation at Kamaishi bay. The almost breakwaters were washed away, whose situation was similar to the damage at Kamaishi bay. REFERENCES T. Arikawa and T. Tomita (2016): "Development of High Precision Tsunami Runup Calculation Method Based on a Hierarchical Simulation", Journal of Disaster ResearchVol.11 No.4 T. Arikawa, K. Hamaguchi, K. Kitagawa, T. Suzuki (2009): "Development of Numerical Wave Tank Coupled with Structure Analysis Based on FEM", Journal of J.S.C.E., Ser. B2 (Coastal Engineering) Vol. 65, No. 1 T. Arikawa et. al.(2012) "Failure Mechanism of Kamaishi Breakwaters due to the Great East Japan Earthquake Tsunami", 33rd International Conference on Coastal Engineering, No.1191

Application and Validation of a GIS Model for Local Tsunami Vulnerability and Mortality Risk Analysis

NASA Astrophysics Data System (ADS)

Harbitz, C. B.; Frauenfelder, R.; Kaiser, G.; Glimsdal, S.; Sverdrup-thygeson, K.; Løvholt, F.; Gruenburg, L.; Mc Adoo, B. G.

2015-12-01

The 2011 Tōhoku tsunami caused a high number of fatalities and massive destruction. Data collected after the event allow for retrospective analyses. Since 2009, NGI has developed a generic GIS model for local analyses of tsunami vulnerability and mortality risk. The mortality risk convolves the hazard, exposure, and vulnerability. The hazard is represented by the maximum tsunami flow depth (with a corresponding likelihood), the exposure is described by the population density in time and space, while the vulnerability is expressed by the probability of being killed as a function of flow depth and building class. The analysis is further based on high-resolution DEMs. Normally a certain tsunami scenario with a corresponding return period is applied for vulnerability and mortality risk analysis. Hence, the model was first employed for a tsunami forecast scenario affecting Bridgetown, Barbados, and further developed in a forecast study for the city of Batangas in the Philippines. Subsequently, the model was tested by hindcasting the 2009 South Pacific tsunami in American Samoa. This hindcast was based on post-tsunami information. The GIS model was adapted for optimal use of the available data and successfully estimated the degree of mortality.For further validation and development, the model was recently applied in the RAPSODI project for hindcasting the 2011 Tōhoku tsunami in Sendai and Ishinomaki. With reasonable choices of building vulnerability, the estimated expected number of fatalities agree well with the reported death toll. The results of the mortality hindcast for the 2011 Tōhoku tsunami substantiate that the GIS model can help to identify high tsunami mortality risk areas, as well as identify the main risk drivers.The research leading to these results has received funding from CONCERT-Japan Joint Call on Efficient Energy Storage and Distribution/Resilience against Disasters (http://www.concertjapan.eu; project RAPSODI - Risk Assessment and design of Prevention Structures fOr enhanced tsunami DIsaster resilience http://www.ngi.no/en/Project-pages/RAPSODI/), and from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, STrategy And Risk reduction for Tsunamis in Europe http://www.astarte-project.eu/).

New Tsunami Response, Mitigation, and Recovery Planning "Playbooks" for California (USA) Maritime Communities

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Lynett, P. J.; Miller, K.; Eskijian, M.; Dengler, L. A.; Ayca, A.; Keen, A.; Admire, A. R.; Siegel, J.; Johnson, L. A.; Curtis, E.; Hornick, M.

2015-12-01

The 2010 Chile and 2011 Japan tsunamis both struck the California coast offering valuable experience and raised a number of significant issues for harbor masters, port captains, and other maritime entities. There was a general call for more planning products to help guide maritime communities in their tsunami response, mitigation, and recovery activities. The State of California is working with the U.S. Federal Emergency Management Agency (FEMA), the U.S. National Tsunami Hazard Mitigation Program (NTHMP), and other tsunami experts to provide communities with new tsunami planning tools to address these issues: Response Playbooks and plans have been developed for ports and harbors identifying potential tsunami current hazards and related damage for various size events. Maps have been generated showing minor, moderate, and severe damage levels that have been linked to current velocity thresholds of 3, 6, and 9 knots, respectively. Knowing this information allows harbor personnel to move ships or strengthen infrastructure prior to the arrival of distant source tsunamis. Damage probability tools and mitigation plans have been created to help reduce tsunami damage by evaluating the survivability of small and large vessels in harbors and ports. These results were compared to the actual damage assessments performed in California and Japan following the 2011 Japanese tsunami. Fragility curves were developed based on current velocity and direction to help harbor and port officials upgrade docks, piles, and related structures. Guidance documents are being generated to help in the development of both local and statewide recovery plans. Additional tools, like post-tsunami sediment and debris movement models, will allow harbors and ports to better understand if and where recovery issues are most likely to occur. Streamlining the regulatory and environmental review process is also a goal of the guidance. These maritime products and procedures are being integrated into guidance through the NTHMP to help other U.S. states/territories/commonwealths develop their own tsunami planning tools. This will lead to more accurate, consistent, and cost-effective tsunami planning strategies within the U.S.

A method to estimate expected fatalities and economic loss of buildings in an urban environment as a step toward tsunami risk assessment: an application to the city of Siracusa, Italy.

NASA Astrophysics Data System (ADS)

Pagnoni, Gianluca; Accorsi, Eleonora; Tinti, Stefano

2016-04-01

Siracusa, an important city of the south-east Sicily, is located in an area highly exposed to the danger of tsunami, local and remote. Among the many events that affected this area those with a major effect are the AD 365 tsunami generated by an earthquake in the Western Hellenic Arc, the event of 11 January 1693, following an earthquake in the area of Augusta, and the tsunami of 28 December 1908 generated in the Messina strait. The aim of this study is to evaluate the number of exposed people and of fatalities as well as the type of damage to constructions and the associated loss of economic value in case of a tsunami, based on a simple tsunami scenario, i.e. on assuming a uniform inundation level of 5 m. This figure is considered appropriate for this preliminary tsunami loss analysis since it is compatible with historical tsunami observations and is also supported by recent tsunami hazard studies carried out for this area (Armigliato et al., 2015). The main physical tsunami parameter used in computations is the water column, which is merely the difference between the assumed inundation level and the topographic altitude. We use numerical geo-referenced 1:2000 maps providing a database of constructions in the area of Siracusa together with data from national and local statistical institutions to make estimates on the number and type of buildings and on the number of people that may be found in the inundation area in different periods of the year, discriminating between residents and tourists. Using a variant of the Terrier et al. (2012) table and tsunami mortality curves proposed by Koshimura et al. (2009) we are able to estimate expected fatalities with tsunami inundation reaching at most the first floor of buildings. We calculate economic loss by taking into account both residential buildings and commercial-industrial structures and data from the real estate market. This study is funded by the EU Project ASTARTE - "Assessment, STrategy And Risk Reduction for Tsunamis in Europe", Grant 603839, 7th FP (ENV.2013.6.4-3)

Simulation of Tsunami Resistance of a Pinus Thunbergii tree in Coastal Forest in Japan

NASA Astrophysics Data System (ADS)

Nanko, K.; Suzuki, S.; Noguchi, H.; Hagino, H.

2015-12-01

Forests reduce fluid force of tsunami, whereas extreme tsunami sometimes breaks down the forest trees. It is difficult to estimate the interactive relationship between the fluid and the trees because fluid deform tree architecture and deformed tree changes flow field. Dynamic tree deformation and fluid behavior should be clarified by fluid-structure interaction analysis. For the initial step, we have developed dynamic simulation of tree sway and breakage caused by tsunami based on a vibrating system with multiple degrees of freedom. The target specie of the simulation was Japanese black pine (pinus thunbergii), which is major specie in the coastal forest to secure livelihood area from the damage by blown sand and salt in Japanese coastal area. For the simulation, a tree was segmented into 0.2 m long circular truncated cones. Turning moment induced by tsunami and self-weight was calculated at each segment bottom. Tree deformation was computed on multi-degree-of-freedom vibration equation. Tree sway was simulated by iterative calculation of the tree deformation with time step 0.05 second with temporally varied flow velocity of tsunami. From the calculation of bending stress and turning moment at tree base, we estimated resistance of a Pinus thunbergii tree from tsunami against tree breakage.

33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

Tsunami Research driven by Survivor Observations: Sumatra 2004, Tohoku 2011 and the Lituya Bay Landslide (Plinius Medal Lecture)

NASA Astrophysics Data System (ADS)

Fritz, Hermann M.

2014-05-01

The 10th anniversary of the 2004 Indian Ocean tsunami recalls the advent of tsunami video recordings by eyewitnesses. The tsunami of December 26, 2004 severely affected Banda Aceh along the North tip of Sumatra (Indonesia) at a distance of 250 km from the epicenter of the Magnitude 9.0 earthquake. The tsunami flow velocity analysis focused on two survivor videos recorded within Banda Aceh more than 3km from the open ocean. The exact locations of the tsunami eyewitness video recordings were revisited to record camera calibration ground control points. The motion of the camera during the recordings was determined. The individual video images were rectified with a direct linear transformation (DLT). Finally a cross-correlation based particle image velocimetry (PIV) analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields. The measured overland tsunami flow velocities were within the range of 2 to 5 m/s in downtown Banda Aceh, Indonesia. The March 11, 2011, magnitude Mw 9.0 earthquake off the coast of Japan caused catastrophic damage and loss of life. Fortunately many survivors at evacuation sites recorded countless tsunami videos with unprecedented spatial and temporal coverage. Numerous tsunami reconnaissance trips were conducted in Japan. This report focuses on the surveys at selected tsunami eyewitness video recording locations along Japan's Sanriku coast and the subsequent tsunami video image analysis. Locations with high quality survivor videos were visited, eyewitnesses interviewed and detailed site topography scanned with a terrestrial laser scanner (TLS). The analysis of the tsunami videos followed the four step procedure developed for the analysis of 2004 Indian Ocean tsunami videos at Banda Aceh. Tsunami currents up to 11 m/s were measured in Kesennuma Bay making navigation impossible. Further tsunami height and runup hydrographs are derived from the videos to discuss the complex effects of coastal structures on inundation and outflow flow velocities. Tsunamis generated by landslides and volcanic island collapses account for some of the most catastrophic events. On July 10, 1958, an earthquake Mw 8.3 along the Fairweather fault triggered a major subaerial landslide into Gilbert Inlet at the head of Lituya Bay on the south coast of Alaska. The landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history. This event was observed by eyewitnesses on board the sole surviving fishing boat, which managed to ride the tsunami. The mega-tsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis. A cross-section of Gilbert Inlet was rebuilt in a two dimensional physical laboratory model. Particle image velocimetry (PIV) provided instantaneous velocity vector fields of decisive initial phase with landslide impact and wave generation as well as the runup on the headland. Three dimensional source and runup scenarios based on real world events are physically modeled in the NEES tsunami wave basin (TWB) at Oregon State University (OSU). The measured landslide and tsunami data serve to validate and advance numerical landslide tsunami models. This lecture encompasses multi-hazard aspects and implications of recent tsunami and cyclonic events around the world such as the November 2013 Typhoon Haiyan (Yolanda) in the Philippines.

A case study of middle size floating airports for shallower and deeper waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshida, Koichiro; Suzuki, Hideyuki; Nishigaki, Makoto

1996-12-31

Demands for large and middle size airports are expanding in Japan with continuous increase of air transportation. However these demands will not be satisfied without effective ocean space utilization. Most of the wide and shallower waters suitable for reclamation have already been reclaimed. Furthermore those shallower waters are generally close to the residential area, and noise and environmental problems will be caused if they were used for airports. Deeper waters, which are relatively distant from the shore, are suitable for airport but reclamation of these waters are extremely difficult. This paper presents a structural planning of an open sea typemore » middle size floating airport to promote local economy and also improve transportation infrastructure of isolated islands. The airports of this plan are a semisubmersible type floating structure with a relatively thin deck, a number of slender columns and large size lower hulls. The floating structure is moored by inclined tension legs to restrain the motion. The diameter of the leg becomes much larger compared with the legs of existing tension leg platforms. Parameters related to the configuration of the floating structure and the mooring system are determined by comparing analyses results with the proper design criteria. Several kinds of static and dynamic computer programs are used in the planning. The proposed structural plan and the mooring system are considered as a typical floating airport appropriate for the open sea.« less

Combining historical eyewitness accounts on tsunami-induced waves and numerical simulations for getting insights in uncertainty of source parameters

NASA Astrophysics Data System (ADS)

Rohmer, Jeremy; Rousseau, Marie; Lemoine, Anne; Pedreros, Rodrigo; Lambert, Jerome; benki, Aalae

2017-04-01

Recent tsunami events including the 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami have caused many casualties and damages to structures. Advances in numerical simulation of tsunami-induced wave processes have tremendously improved forecast, hazard and risk assessment and design of early warning for tsunamis. Among the major challenges, several studies have underlined uncertainties in earthquake slip distributions and rupture processes as major contributor on tsunami wave height and inundation extent. Constraining these uncertainties can be performed by taking advantage of observations either on tsunami waves (using network of water level gauge) or on inundation characteristics (using field evidence and eyewitness accounts). Despite these successful applications, combining tsunami observations and simulations still faces several limitations when the problem is addressed for past tsunamis events like 1755 Lisbon. 1) While recent inversion studies can benefit from current modern networks (e.g., tide gauges, sea bottom pressure gauges, GPS-mounted buoys), the number of tide gauges can be very scarce and testimonies on tsunami observations can be limited, incomplete and imprecise for past tsunamis events. These observations often restrict to eyewitness accounts on wave heights (e.g., maximum reached wave height at the coast) instead of the full observed waveforms; 2) Tsunami phenomena involve a large span of spatial scales (from ocean basin scales to local coastal wave interactions), which can make the modelling very demanding: the computation time cost of tsunami simulation can be very prohibitive; often reaching several hours. This often limits the number of allowable long-running simulations for performing the inversion, especially when the problem is addressed from a Bayesian inference perspective. The objective of the present study is to overcome both afore-described difficulties in the view to combine historical observations on past tsunami-induced waves and numerical simulations. In order to learn the uncertainty information on source parameters, we treat the problem within the Bayesian setting, which enables to incorporate in a flexible manner the different uncertainty sources. We propose to rely on an emerging technique called Approximate Bayesian Computation ABC, which has been developed to estimate the posterior distribution in modelling scenarios where the likelihood function is either unknown or cannot be explicitly defined. To overcome the computational issue, we combine ABC with statistical emulators (aka meta-model). We apply the proposed approach on the case study of Ligurian (North West of Italy) tsunami (1887) and discuss the results with a special attention paid to the impact of the observational error.

2011 Great East Japan tsunami in Okhotsk Sea region: numerical modelings and observation data

NASA Astrophysics Data System (ADS)

Kostenko, Irina; Zaytsev, Andrey; Yalciner, Ahmet; Pelinovsky, Efim

2013-04-01

The 11 March, 2011 Great East Japan Earthquake with Mw: 9.0 occurred at 05:46:23 UTC with its epicenter estimated at 38.322_N, 142.369_E, and focal depth of 32 km (USGS, 2011). Tsunami waves propagated in Pacific Ocean to all directions. At Russian coast the highest waves were observed in the Kuril Islands (Malokurilskoye, Kunashir Island) which located in between Pacific ocean and the Okhotsk Sea. Kuril island provides limited transmission of tsunami waves from Pacific ocean. tsunami In 2011 Great East Japan Earthquake and Tsunami event, the maximum amplitude of the tsunami was observed as 3 m in Kuril islands. However, tsunami arrived Okhotsk Sea losing a significant amount of energy. Therefore the tsunami amplitudes at the coast of the Okhotsk Sea were smaller. In order to estimate the level of energy loss while passing through the narrow straits of the Kuril Islands, a series of numerical simulations was done by using tsunami numerical code NAMI DANCE. Ten largest earthquake shocks capable of generating tsunami were used as inputs of tsunami sources in the modeling. Hence the relation between the transmission of tsunami and the dimensions of the straits are compared and discussed. Finally the characteristics of tsunami propagation (arrival time and coastal amplification) at the coast in the Okhotsk Sea. The varying grid structure is used in numerical modeling in order to make finer analysis of tsunami passing through narrow straits of the Kuril Islands. This allows to combine exactly the installation locations of stationary and computational gauges. The simulation results are compared with the observations. The linear form of shallow water equations are used in the deep ocean region offshore part of the Sea of Okhotsk. Boussinesq type equations were also used at the near shore area in simulations. Since the Okhotsk Sea Results are a semi enclosed basin, the reflection characteristics at the coastal boundaries may be important. The numerical experiments are also extended to investigate the spectral characteristics of the time histories of water level fluctuations in Okhotsk Results is a semi enclosed basin, the reflection characteristics at the coastal boundaries by comparing with the instrumental data from coastal locations. As the summary, the transmission characteristics of tsunami at Kuril islands, the propagation, coastal amplification and reflection characteristics of tsunamis in the Okhotsk Sea are investigated and presented. This study was partly supported by Russian Federation President Award .1935.2012.5

Tsunami prevention and mitigation necessities and options derived from tsunami risk assessment in Indonesia

NASA Astrophysics Data System (ADS)

Post, J.; Zosseder, K.; Wegscheider, S.; Steinmetz, T.; Mück, M.; Strunz, G.; Riedlinger, T.; Anwar, H. Z.; Birkmann, J.; Gebert, N.

2009-04-01

Risk and vulnerability assessment is an important component of an effective End-to-End Tsunami Early Warning System and therefore contributes significantly to disaster risk reduction. Risk assessment is a key strategy to implement and design adequate disaster prevention and mitigation measures. The knowledge about expected tsunami hazard impacts, exposed elements, their susceptibility, coping and adaptation mechanisms is a precondition for the development of people-centred warning structures, local specific response and recovery policy planning. The developed risk assessment and its components reflect the disaster management cycle (disaster time line) and cover the early warning as well as the emergency response phase. Consequently the components hazard assessment, exposure (e.g. how many people/ critical facilities are affected?), susceptibility (e.g. are the people able to receive a tsunami warning?), coping capacity (are the people able to evacuate in time?) and recovery (are the people able to restore their livelihoods?) are addressed and quantified. Thereby the risk assessment encompasses three steps: (i) identifying the nature, location, intensity and probability of potential tsunami threats (hazard assessment); (ii) determining the existence and degree of exposure and susceptibility to those threats; and (iii) identifying the coping capacities and resources available to address or manage these threats. The paper presents results of the research work, which is conducted in the framework of the GITEWS project and the Joint Indonesian-German Working Group on Risk Modelling and Vulnerability Assessment. The assessment methodology applied follows a people-centred approach to deliver relevant risk and vulnerability information for the purposes of early warning and disaster management. The analyses are considering the entire coastal areas of Sumatra, Java and Bali facing the Sunda trench. Selected results and products like risk maps, guidelines, decision support information and other GIS products will be presented. The focus of the products is on the one hand to provide relevant risk assessment products as decision support to issue a tsunami warning within the early warning stage. On the other hand the maps and GIS products shall provide relevant information to enable local decision makers to act adequately concerning their local risks. It is shown that effective prevention and mitigation measures can be designed based on risk assessment results and information especially when used pro-active and beforehand a disaster strikes. The conducted hazard assessment provides the probability of an area to be affected by a tsunami threat divided into two ranked impact zones. The two divided impact zones directly relate to tsunami warning levels issued by the Early Warning Center and consequently enable the local decision maker to base their planning (e.g. evacuation) accordingly. Within the tsunami hazard assessment several hundred pre-computed tsunami scenarios are analysed. This is combined with statistical analysis of historical event data. Probabilities of tsunami occurrence considering probabilities of different earthquake magnitudes, occurrences of specific wave heights at coast and spatial inundation probability are computed. Hazard assessment is then combined with a comprehensive vulnerability assessment. Here deficits in e.g. people's ability to receive and understand a tsunami warning and deficits in their ability to respond adequately (evacuate on time) are quantified and are visualized for the respective coastal areas. Hereby socio-economic properties (determining peoples ability to understand a warning and to react) are combined with environmental conditions (land cover, slope, population density) to calculate the time needed to evacuate (reach a tsunami safe area derived through the hazard assessment). This is implemented using a newly developed GIS cost-distance weighting approach. For example, the amount of people affected in a certain area is dependent on expected tsunami intensity, inundated area, estimated tsunami arrival time and available time for evacuation. Referring to the Aceh 2004 Tsunami, an estimated amount of people affected (dead/injured) of 21000 for Kabubaten Aceh Jaya and 85000 for Kab. Banda Aceh is in a comparable range with reported values of 19661 and 78417 (JICA 2005) respectively. Hence the established methodology provides reliable estimates of people affected and people's ability to reach a safe area. Based on the spatial explicit detection of e.g. high tsunami risk areas (and the assessed root causes therefore), specific disaster risk reduction and early warning strategies can be designed. For example additional installation of technical warning dissemination device, community based preparedness and awareness programmes (education), structural and non-structural measures (e.g. land use conversion, coastal engineering), effective evacuation, contingency and household recovery aid planning can be employed and/or optimized within high tsunami risk areas as a first priority. In the context of early warning, spatially distributed information like degree of expected hazard impact, exposure of critical facilities (e.g. hospitals, schools), potential people dead/injured depending on available response times, location of safe and shelter areas can be disseminated and used for decision making. Keywords: Tsunami risk, hazard and vulnerability assessment, early warning, tsunami mitigation and prevention, Indonesia

18 CFR 1304.400 - Flotation devices and material, all floating structures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Flotation devices and material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... structures. (a) All flotation for docks, boat mooring buoys, and other water-use structures and facilities...

18 CFR 1304.400 - Flotation devices and material, all floating structures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Flotation devices and material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... structures. (a) All flotation for docks, boat mooring buoys, and other water-use structures and facilities...

Preparation and investigation of novel gastro-floating tablets with 3D extrusion-based printing.

PubMed

Li, Qijun; Guan, Xiaoying; Cui, Mengsuo; Zhu, Zhihong; Chen, Kai; Wen, Haoyang; Jia, Danyang; Hou, Jian; Xu, Wenting; Yang, Xinggang; Pan, Weisan

2018-01-15

Three dimensional (3D) extrusion-based printing is a paste-based rapid prototyping process, which is capable of building complex 3D structures. The aim of this study was to explore the feasibility of 3D extrusion-based printing as a pharmaceutical manufacture technique for the fabrication of gastro-floating tablets. Novel low-density lattice internal structure gastro-floating tablets of dipyridamole were developed to prolong the gastric residence time in order to improve drug release rate and consequently, improve bioavailability and therapeutic efficacy. Excipients commonly employed in the pharmaceutical study could be efficiently applied in the room temperature 3D extrusion-based printing process. The tablets were designed with three kinds of infill percentage and prepared by hydroxypropyl methylcellulose (HPMC K4M) and hydroxypropyl methylcellulose (HPMC E15) as hydrophilic matrices and microcrystalline cellulose (MCC PH101) as extrusion molding agent. In vitro evaluation of the 3D printed gastro-floating tablets was performed by determining mechanical properties, content uniformity, and weight variation. Furthermore, re-floating ability, floating duration time, and drug release behavior were also evaluated. Dissolution profiles revealed the relationship between infill percentage and drug release behavior. The results of this study revealed the potential of 3D extrusion-based printing to fabricate gastro-floating tablets with more than 8h floating process with traditional pharmaceutical excipients and lattice internal structure design. Copyright © 2017. Published by Elsevier B.V.

The response of pile-guided floats subjected to dynamic loading.

DOT National Transportation Integrated Search

2014-08-01

Pile-Guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to dynamic : forces such as wind generated waves and impacts from vessels. This project developed a rational basis for esti...

Observations of Scour and Transport at Coastal Structures from the 2011 Tohoku Tsunami - Implications for Flow in Natural Terrain

NASA Astrophysics Data System (ADS)

Petroff, C. M.

2011-12-01

Before the March 11, 2011 Tohoku tsunami, many communities along the Japan coast had shore protection barriers, some designed specifically to provide protection from tsunamis and others for typhoon and storm surge protection. A vast number of these structures were overtopped, damaged or destroyed by the high inundation and currents generated in the tsunami. Observations are presented about scour features at man-made coastal structures in the Tohoku region as well as the hydraulic transport of debris from these structures. Along with providing lessons for structure design and maintenance, these observations have implications for hydraulic transport in natural terrain, not only at hard points such as rock outcrops but also at other features such as river mouths, barrier islands and coastal dunes. As an example, Photo 1 shows the overtopping flow at the seawall at Noda, in the Iwate prefecture. From the point of view of hydraulics the type of flow seen in the photo is more like that at an in-line weir or spillway than the wave conditions for which the structure was designed. On the lee or downstream side of such structures, the flow is supercritical resulting in a supercritical to subcritical transition near the landward toe of the seawall. High flow velocities along with increased pore pressure and overturning flow create very deep scour in these locations Such as the zone clearly seen in Photo 2 behind the seawall at the Sendai airport. It is anticipated that similar hydraulic conditions would occur for flow over a high coastal dune ridge where the ridge would act as a flow control point and locally high velocities on the landward side of the ridge would result in high erosion and scour. Other examples are given.

Active structural control of a floating wind turbine with a stroke-limited hybrid mass damper

NASA Astrophysics Data System (ADS)

Hu, Yaqi; He, Erming

2017-12-01

Floating wind turbines are subjected to more severe structural loads than fixed-bottom wind turbines due to additional degrees of freedom (DOFs) of their floating foundations. It's a promising way of using active structural control method to improve the structural responses of floating wind turbines. This paper investigates an active vibration control strategy for a barge-type floating wind turbine by setting a stroke-limited hybrid mass damper (HMD) in the turbine's nacelle. Firstly, a contact nonlinear modeling method for the floating wind turbine with clearance between the HMD and the stroke limiters is presented based on Euler-Lagrange's equations and an active control model of the whole system is established. The structural parameters are validated for the active control model and an equivalent load coefficient method is presented for identifying the wind and wave disturbances. Then, a state-feedback linear quadratic regulator (LQR) controller is designed to reduce vibration and loads of the wind turbine, and two optimization methods are combined to optimize the weighting coefficients when considering the stroke of the HMD and the active control power consumption as constraints. Finally, the designed controllers are implemented in high fidelity simulations under five typical wind and wave conditions. The results show that active HMD control strategy is shown to be achievable and the designed controllers could further reduce more vibration and loads of the wind turbine under the constraints of stroke limitation and power consumption. "V"-shaped distribution of the TMD suppression effect is inconsistent with the Weibull distribution in practical offshore floating wind farms, and the active HMD control could overcome this shortcoming of the passive TMD.

Investigation of Possible Tsunami Events on the Eastern Coast of Taiwan: Case Studies of Lu-Ye, Changping, and Tulan.

NASA Astrophysics Data System (ADS)

Laksono, A. T., Jr.; Tsai, L. L. Y., Sr.

2017-12-01

Major earthquakes had occurred in eastern Taiwan for many times. According to an Amis folklore originated in Chengkong City, there was a big sea wave struck their settlement in 1850 AD. Several studies had been conducted, however, the evidence which indicates the tsunami was very weak. There is also a possibility that big sea waves had occurred due to typhoons which take place 3-4 times a year in Taiwan. The purpose of this study is to prove the possibility of tsunami events on the eastern coast of Taiwan based on sedimentological features. The methods in this study are facies analysis including observation of the marine terrace along Lu-Ye, Changping, and Tulan, identification of lithology, sedimentary structure, and fossil content. Lithology analysis is conducted by using point counting of 12 sandstone samples from marine terrace outcrops. Based on the field observation, we found a thin sand marine deposit included in the beach gravel at a height of 10 meters at the Changping marine terrace. It contains coral and some Mollusca shells and does not display any particular sedimentary structure. Sediments that have similar characteristics were also found in the Tulan marine terrace with a height of 5 m. In addition, fossil analysis of marine sand in Tulan exhibits the presence of several planktonic foraminifera fossils such as Orbulina bilobata and Globigerinoides ruber. Temporary interpretation indicates that there is a "super" event which transports shallow marine and beach materials subsequently deposit them on top of an alluvial fan. A 10 cm thin layer of sediment serves as an early tsunami indicator. In addition, the absence of deposits with the same characteristics further indicates that the event occurred only once. Since the eastern coast of Taiwan is an uplift zone with an uplift rate between 5-8 mm/year, the estimated wave height of tsunami should take into account both the tsunami age and the uplift rate. Furthermore, based on the distance from the probable tsunami source and the study area, it is estimated that the tsunami wave was triggered by the thrust fault at the base of the eastern Taiwan margin, which ruptured during a main event of the 19th century. The conclusion of this study is that a tsunami did occur along the eastern coast of Taiwan. An assessment of potential tsunami hazard risk is important and suggested in the future.

An advanced three-phase physical, experimental and numerical method for tsunami induced boulder transport

NASA Astrophysics Data System (ADS)

Oetjen, Jan; Engel, Max; Prasad Pudasaini, Shiva; Schüttrumpf, Holger; Brückner, Helmut

2017-04-01

Coasts around the world are affected by high-energy wave events like storm surges or tsunamis depending on their regional climatological and geological settings. By focusing on tsunami impacts, we combine the abilities and experiences of different scientific fields aiming at improved insights of near- and onshore tsunami hydrodynamics. We investigate the transport of coarse clasts - so called boulders - due to tsunami impacts by a multi-methodology approach of numerical modelling, laboratory experiments, and sedimentary field records. Coupled numerical hydrodynamic and boulder transport models (BTM) are widely applied for analysing the impact characteristics of the transport by tsunami, such as wave height and flow velocity. Numerical models able to simulate past tsunami events and the corresponding boulder transport patterns with high accuracy and acceptable computational effort can be utilized as powerful forecasting models predicting the impact of a coast approaching tsunami. We have conducted small-scale physical experiments in the tilting flume with real shaped boulder models. Utilizing the structure from motion technique (Westoby et al., 2012) we reconstructed real boulders from a field study on the Island of Bonaire (Lesser Antilles, Caribbean Sea, Engel & May, 2012). The obtained three-dimensional boulder meshes are utilized for creating downscaled replica of the real boulder for physical experiments. The results of the irregular shaped boulder are compared to experiments with regular shaped boulder models to achieve a better insight about the shape related influence on transport patterns. The numerical model is based on the general two-phase mass flow model by Pudasaini (2012) enhanced for boulder transport simulations. The boulder is implemented using the immersed boundary technique (Peskin, 2002) and the direct forcing approach. In this method Cartesian grids (fluid and particle phase) and Lagrangian meshes (boulder) are combined. By applying the immersed boundary method we can compute the interactions between fluid, particles and arbitrary boulder shape. We are able to reproduce the exact physical experiment for calibration and verification of the tsunami boulder transport phenomena. First results of the study will be presented. Engel, M.; May, S.M.: Bonaire's boulder fields revisited: evidence for Holocene tsunami impact on the Leeward, Antilles. Quaternary Science Reviews 54, 126-141, 2012. Peskin, C.S.: The immersed boundary method. Acta Numerica, 479 - 517, 2002. Pudasaini, S. P.: A general two-phase debris flow model. J. Geophys. Res. Earth Surf., 117, F03010, 2012. Westoby, M.J.; Brasington, J.; Glasser, N.F.; Hambrey, M.J.; Reynolds, J.M.: 'Structure-from-Motion' photogrammetry - a low-cost, effective tool for geoscience applications. Geomorphology 179, 300-314, 2012.

The September 16, 2015 Illapel Tsunami - Sedimentology of tsunami deposits at the beaches of La Serena and Coquimbo

NASA Astrophysics Data System (ADS)

Bahlburg, H.; Nentwig, V.; Kreutzer, M.

2016-12-01

On September 16, 2015, a Mw 8.3 earthquake occurred off the coast of Central Chile, 46 km west of the town of Illapel, the hypocenter was at a depth of 8.7 km in the transition zone from the Chilean flat slab to the central Chilean steep slab subduction geometry, and near the intersection of the Juan Fernandez Ridge with the South America plate. The quake caused a tsunami registered which at Coquimbo and La Serena (c. 30°S) attained wave heights of 4.5 m leading to flooding and destruction of infrastructure. Maximum inundation distance was c. 700 m in Coquimbo Bay with minor flooding at the beaches of La Serena to the N. Tsunami deposits are usually the only observable evidence of past events. In view of a limited preservation potential, it is of paramount importance to undertake detailed studies in the wake of actual events. We report initial field data of a sedimentological post-tsunami field survey undertaken in October 2015. The most comprehensive sedimentological record of this tsunami is preserved at Playa Los Fuertes in La Serena. Along a 30 m long trench perpendicular to the coast we observed a laminated package of tsunami deposits. Above an erosive basal unconformity with an amplitude of up to 50 cm the deposit consists of 6 layers of variable thickness, ranging between dark laminae a few millimeters thick and rich in heavy minerals, and lighter colored sand layers up to 15 cm thick. The sediments are moderately well to well sorted, unimodal with modes between 1.3 and 2.0 Φ (medium sand). Cross-beds in the lower four layers indicate deposition from tsunami inflow, cross bedding in the penultimate layer records outflow. Water escape through small sand volcanoes was coeval to formation of the overlying sediment layer by traction deposition. This simultaneity is indicated by sand issued from the lower layer which has been preserved as a thin plume deformed in the downcurrent, i.e. landward, direction in the newly forming upper layer. Other sectors of the sediment show sand diapirs intruding up to 15 cm into the overlying tsunami deposit. The assemblage of laminae, layers and sedimentary structures indicates that the deposit records at least 4 events of tsunami inflow and one outflow event. Intervening layers without directional structures cannot be assigned unequivocally to either inflow or outflow deposition.

Impacts of the 2011 Tohoku-oki tsunami along the Sendai coast protected by hard and soft seawalls; interpretations of satellite images, helicopter-borne video footage and field studies

NASA Astrophysics Data System (ADS)

Tappin, D. R.; Jordan, H. M.; Jordan, C. J.; Richmond, B. M.; Sugawara, D.; Goto, K.

2012-12-01

A combination of time-series satellite imagery, helicopter-borne video footage and field observation is used to identify the impact of a major tsunami on a low-lying coastal zone located in eastern Japan. A comparison is made between the coast protected by hard sea walls and the coast without. Changes to the coast are mapped from before and after imagery, and sedimentary processes identified from the video footage. The results are validated by field observations. The impact along a 'natural' coast, with minimal defences, is erosion focussed on the back beach. There is little erosion (or sedimentation) of the whole beach, and where active, erosion mainly forms V-shaped channels that are initiated during the tsunami flood and then further developed during backwash. Enigmatic, short lived, 'strand lines' are attributed to the slow fall of sea level after such a major tsunami. Backwash on such a low lying area takes place as sheet flood immediately after tsunami flooding has ceased, and then subsequently, when the water level landward of coastal ridges falls below their elevation, becomes confined to channels formed on the coastal margin by the initial tsunami impact. Immediately after the tsunami coastal reconstruction begins, sourced from the sediment recently flushed into the sea by tsunami backwash. Hard engineering structures are found to be small defence against highly energetic tsunami waves that overtop them. The main cause of damage is scouring at the landward base of concrete-faced embankments constructed to defend the coast from erosion, that results in foundation-weakening and collapse.

Comparison of Tsunami Deposits Surveyed in 2010 and 2015 From the 2010 Maule Earthquake and Tsunami in South-Central Chile.

NASA Astrophysics Data System (ADS)

Ruiz, A. C.; MacInnes, B. T.; Ely, L. L.; Cisternas, M. A.; Gelfenbaum, G. R.; Richmond, B. M.; Meneses, D. J.

2015-12-01

The February 27, 2010 Mw 8.8 Maule earthquake and tsunami that struck south-central Chile altered the coastal landscape, leaving a depositional record at many locations along the coast. Our research is questioning whether tsunami deposits originally described during post-tsunami surveys in La Trinchera, Constitución and Coliumo soon after the event change significantly over time. The deposits initially described in 2010 were revisited 5 years later to determine if taphonomic changes occurred and to assess the long-term preservation potential of deposits with different initial characteristics and settings. We recently made measurements of deposit thickness, grain size, grading, sedimentary structures, incipient soil development and accumulation of organic material. Results indicate that deposit thickness and the maximum inland extent of recognizable deposits had decreased slightly since 2010, while overlying soil development and accumulation of organic matter increased. Few deposits had been altered by bioturbation. We will use the inland extent of the deposits surveyed in 2015 to model a minimum size of the 2010 earthquake and tsunami in GeoClaw. The results will be compared with independent geophysical models of the rupture characteristics. This can be used as a case study that can be applied to earlier paleo-earthquake and tsunami events in which seismic data is sparse or non-existent and the most reliable record is the inundation distance as determined by tsunami deposits. Studying the change of deposits in the geologic record over time can provide key insights into how tsunami deposits are preserved, which is important when working with paleo-deposits that may have been altered since deposition.

Propagation of uncertainties for an evaluation of the Azores-Gibraltar Fracture Zone tsunamigenic potential

NASA Astrophysics Data System (ADS)

Antoshchenkova, Ekaterina; Imbert, David; Richet, Yann; Bardet, Lise; Duluc, Claire-Marie; Rebour, Vincent; Gailler, Audrey; Hébert, Hélène

2016-04-01

The aim of this study is to assess evaluation the tsunamigenic potential of the Azores-Gibraltar Fracture Zone (AGFZ). This work is part of the French project TANDEM (Tsunamis in the Atlantic and English ChaNnel: Definition of the Effects through numerical Modeling; www-tandem.cea.fr), special attention is paid to French Atlantic coasts. Structurally, the AGFZ region is complex and not well understood. However, a lot of its faults produce earthquakes with significant vertical slip, of a type that can result in tsunami. We use the major tsunami event of the AGFZ on purpose to have a regional estimation of the tsunamigenic potential of this zone. The major reported event for this zone is the 1755 Lisbon event. There are large uncertainties concerning source location and focal mechanism of this earthquake. Hence, simple deterministic approach is not sufficient to cover on the one side the whole AGFZ with its geological complexity and on the other side the lack of information concerning the 1755 Lisbon tsunami. A parametric modeling environment Promethée (promethee.irsn.org/doku.php) was coupled to tsunami simulation software based on shallow water equations with the aim of propagation of uncertainties. Such a statistic point of view allows us to work with multiple hypotheses simultaneously. In our work we introduce the seismic source parameters in a form of distributions, thus giving a data base of thousands of tsunami scenarios and tsunami wave height distributions. Exploring our tsunami scenarios data base we present preliminary results for France. Tsunami wave heights (within one standard deviation of the mean) can be about 0.5 m - 1 m for the Atlantic coast and approaching 0.3 m for the English Channel.

Summary of Paleotsunami Investigations in Aliomanu, Anahola, Kauai

NASA Astrophysics Data System (ADS)

Griswold, F. R.; La Selle, S.; Richmond, B. M.; Jaffe, B. E.; Gelfenbaum, G. R.; Chague-Goff, C.; LeVeque, R. J.; Bellanova, P.; Sugawara, D.; Nelson, A. R.

2016-12-01

The Hawaiian Islands are susceptible to tsunami hazards from both local and distant sources. Damaging historical tsunamis, such as the 1946 and 1957 Aleutian, and 1960 Chile tsunamis, have been observed in the Hawaiian Islands, but little is known about prehistoric tsunami events. We conducted a field survey in a freshwater marsh in Anahola Valley, on the northeast shore of Kauai, looking for prehistoric tsunami deposits. Cores were collected at 142 sites, spanning to 700 meters inland, using a vibracore, gouge augers, and Russian D-corer. The coring reveals the presence of at least three marine sand layers, which all exhibit a sharp basal contact with underlying marsh peats and muds. The two uppermost sand layers were dated by measuring 137Cs activity in the upper 50 cm of several cores. These sands were likely deposited by the 1946 and 1957 Aleutian tsunamis, both of which were observed by residents in Anahola Valley, with recorded run-ups of 5.2 m and 4.9 m, respectively. The deepest sand layer was deposited approximately 700 cal yr B.P. and may correspond to recently discovered tsunami deposits on Sedanka Island in the Aleutian Islands. In order to characterize the structure and composition of the deeper sand unit, as well as its possible origin, grain size, CT scan, and X-Ray fluorescence data were collected from the cores. We are modeling tsunami propagation and inundation in Anahola Valley to test whether the observed deposits are consistent with an Aleutian subduction zone earthquake source. Additional field investigations and analyses of candidate tsunami deposits are required in order to map the extent of this deposit throughout the Hawaiian Islands and to determine a probable source of this event.

Quantifying Thin Mat Floating Marsh Strength and Interaction with Hydrodynamic Conditions

NASA Astrophysics Data System (ADS)

Collins, J. H., III; Sasser, C.; Willson, C. S.

2016-12-01

Louisiana possesses over 350,000 acres of unique floating vegetated systems known as floating marshes or flotants. Floating marshes make up 70% of the Terrebonne and Barataria basin wetlands and exist in several forms, mainly thick mat or thin mat. Salt-water intrusion, nutria grazing, and high-energy wave events are believed to be some contributing factors to the degradation of floating marshes; however, there has been little investigation into the hydrodynamic effects on their structural integrity. Due to their unique nature, floating marshes could be susceptible to changes in the hydrodynamic environment that may result from proposed river freshwater and sediment diversion projects introducing flow to areas that are typically somewhat isolated. This study aims to improve the understanding of how thin mat floating marshes respond to increased hydrodynamic stresses and, more specifically, how higher water velocities might increase the washout probability of this vegetation type. There are two major components of this research: 1) A thorough measurement of the material properties of the vegetative mats as a root-soil matrix composite material; and 2) An accurate numerical simulation of the hydrodynamics and forces imposed on the floating marsh mats by the flow. To achieve these goals, laboratory and field experiments were conducted using a customized device to measure the bulk properties of typical floating marshes. Additionally, Delft-3D FLOW and ANSYS FLUENT were used to simulate the flow around a series of simplified mat structures in order to estimate the hydrodynamic forcings on the mats. The hydrodynamic forcings are coupled with a material analysis, allowing for a thorough analysis of their interaction under various conditions. The 2-way Fluid Structure Interaction (F.S.I.) between the flow and the mat is achieved by coupling a Finite Element Analysis (F.E.A.) solver in ANSYS with FLUENT. The flow conditions necessary for the structural failure of the floating marshes are determined for a multitude of mat shapes and sizes, leading to a quantifiable critical velocity required for washout. Ultimately, through dimensional analysis, an equation for washout potential will be developed from the results, which could be used as a design guideline.

Getting out of harm's way - evacuation from tsunamis

USGS Publications Warehouse

Jones, Jeanne M.; Wood, Nathan J.; Gordon, Leslie C.

2015-01-01

Maps of travel time can be used by emergency managers and community planners to identify where to focus evacuation training and tsunami education. The tool can also be used to examine the potential benefits of vertical-evacuation structures, which are buildings or berms designed to provide a local high ground in low-lying areas of the hazard zone. 

Development of Multi-Layered Floating Floor for Cabin Noise Reduction

NASA Astrophysics Data System (ADS)

Song, Jee-Hun; Hong, Suk-Yoon; Kwon, Hyun-Wung

2017-12-01

Recently, regulations pertaining to the noise and vibration environment of ship cabins have been strengthened. In this paper, a numerical model is developed for multi-layered floating floor to predict the structure-borne noise in ship cabins. The theoretical model consists of multi-panel structures lined with high-density mineral wool. The predicted results for structure-borne noise when multi-layered floating floor is used are compared to the measure-ments made of a mock-up. A comparison of the predicted results and the experimental one shows that the developed model could be an effective tool for predicting structure-borne noise in ship cabins.

2011 Tohoku Earthquake and Japan's Nuclear Disaster - Implications for Indian Ocean Rim countries

NASA Astrophysics Data System (ADS)

Chadha, R. K.

2011-12-01

The Nuclear disaster in Japan after the M9.0 Tohoku earthquake on March 11, 2011 has elicited global response to have a relook at the safety aspects of the nuclear power plants from all angles including natural hazards like earthquakes and tsunami. Several countries have gone into safety audits of their nuclear programs in view of the experience in Japan. Tectonically speaking, countries located close to subduction zones or in direct line of impact of the subduction zones are the most vulnerable to earthquake or tsunami hazard, as these regions are the locale of great tsunamigenic earthquakes. The Japan disaster has also cautioned to the possibility of great impact to the critical structures along the coasts due to other ocean processes caused by ocean-atmosphere interactions and also due to global warming and sea level rise phenomena in future. This is particular true for island countries. The 2011 Tohoku earthquake in Japan will be remembered more because of its nuclear tragedy and tsunami rather than the earthquake itself. The disaster happened as a direct impact of a tsunami generated by the earthquake 130 km off the coast of Sendai in the Honshu region of Japan. The depth of the earthquake was about 25 km below the ocean floor and it occurred on a thrust fault causing a displacement of more than 20 meters. At few places, water is reported to have inundated areas up to 8-10 km inland. The height of the tsunami varied between 10 and 3 meters along the coast. Generally, during an earthquake damage to buildings or other structures occur due to strong shaking which is expressed in the form of ground accelerations 'g'. Although, Peak Ground Accelerations (PGA) consistently exceeded 2g at several places from Sendai down south, structures at the Fukushima Daiichi Nuclear Power Plant did not collapse due to the earthquake. In the Indian Ocean Rim countries, Indian, Pakistan and South Africa are the three countries where Nuclear power plants are operational, few of them along the coasts. There are a few countries where nuclear installations are planned and hence, a critical analysis is required to know the realistic hazard due to earthquakes and tsunami in these countries. The December 2004 Indian Ocean tsunami generated due to Sumatra earthquake of M9.3 claimed more than 250,000 lives but did not caused a situation like in Japan. We studied the tsunami run-up heights and inundation along the east coast of India. The maximum run-up height of 5.2 meters was observed at Nagapattinam with lateral inundation up to 800 meters and the minimum was at Devanaampatnam with a lateral inundation up to 340 meters. At Kalpakkam Nuclear Power Plant, the tsunami run-up height was 4.1 meters and water entered up to 360 meters inside the campus. Using the observed data we modeled several scenarios for Indian coast line for different earthquakes along the subduction zone of Andaman-Sumatra in the east and Makran in south Pakistan in the western side using N2 Tsunami Model. The results obtained for few critical structures will be presented with an overview of scenarios for other countries.

Tsunami disaster risk management capabilities in Greece

NASA Astrophysics Data System (ADS)

Marios Karagiannis, Georgios; Synolakis, Costas

2015-04-01

Greece is vulnerable to tsunamis, due to the length of the coastline, its islands and its geographical proximity to the Hellenic Arc, an active subduction zone. Historically, about 10% of all world tsunamis occur in the Mediterranean region. Here we review existing tsunami disaster risk management capabilities in Greece. We analyze capabilities across the disaster management continuum, including prevention, preparedness, response and recovery. Specifically, we focus on issues like legal requirements, stakeholders, hazard mitigation practices, emergency operations plans, public awareness and education, community-based approaches and early-warning systems. Our research is based on a review of existing literature and official documentation, on previous projects, as well as on interviews with civil protection officials in Greece. In terms of tsunami disaster prevention and hazard mitigation, the lack of tsunami inundation maps, except for some areas in Crete, makes it quite difficult to get public support for hazard mitigation practices. Urban and spatial planning tools in Greece allow the planner to take into account hazards and establish buffer zones near hazard areas. However, the application of such ordinances at the local and regional levels is often difficult. Eminent domain is not supported by law and there are no regulatory provisions regarding tax abatement as a disaster prevention tool. Building codes require buildings and other structures to withstand lateral dynamic earthquake loads, but there are no provisions for resistance to impact loading from water born debris Public education about tsunamis has increased during the last half-decade but remains sporadic. In terms of disaster preparedness, Greece does have a National Tsunami Warning Center (NTWC) and is a Member of UNESCO's Tsunami Program for North-eastern Atlantic, the Mediterranean and connected seas (NEAM) region. Several exercises have been organized in the framework of the NEAM Tsunami Warning System, with the Greek NWTC actively participating as a Candidate Tsunami Watch Provider. In addition, Greece designed and conducted the first tsunami exercise program in the Union Civil Protection Mechanism in 2011, which also considered the attrition of response capabilities by the earthquake generating the tsunami. These exercises have demonstrated the capability of the Greek NWTC to provide early warning to local civil protection authorities, but warning dissemination to the population remains an issue, especially during the summer season. However, there is no earthquake or tsunami national emergency operations plan, and we found that tsunami disaster planning and preparedness activities are rather limited at the local level. We acknowledge partial support by the project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe) FP7-ENV2013 6.4-3, Grant 603839 to the Technical University of Crete.

The response of pile-guided floats subjected to dynamic loading : volume I final report.

DOT National Transportation Integrated Search

2014-08-01

Pile : - : Guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to dynamic : forces such as wind generated waves and impacts from vessels. This project developed a rational basis fo...

The response of pile-guided floats subjected to dynamic loading : volume II annex.

DOT National Transportation Integrated Search

2014-08-01

Pile-Guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to dynamic : forces such as wind generated waves and impacts from vessels. This project developed a rational basis for esti...

Joint numerical study of the 2011 Tohoku-Oki tsunami: comparative propagation simulations and high resolution coastal models

NASA Astrophysics Data System (ADS)

Loevenbruck, Anne; Arpaia, Luca; Ata, Riadh; Gailler, Audrey; Hayashi, Yutaka; Hébert, Hélène; Heinrich, Philippe; Le Gal, Marine; Lemoine, Anne; Le Roy, Sylvestre; Marcer, Richard; Pedreros, Rodrigo; Pons, Kevin; Ricchiuto, Mario; Violeau, Damien

2017-04-01

This study is part of the joint actions carried out within TANDEM (Tsunamis in northern AtlaNtic: Definition of Effects by Modeling). This French project, mainly dedicated to the appraisal of coastal effects due to tsunami waves on the French coastlines, was initiated after the catastrophic 2011 Tohoku-Oki tsunami. This event, which tragically struck Japan, drew the attention to the importance of tsunami risk assessment, in particular when nuclear facilities are involved. As a contribution to this challenging task, the TANDEM partners intend to provide guidance for the French Atlantic area based on numerical simulation. One of the identified objectives consists in designing, adapting and validating simulation codes for tsunami hazard assessment. Besides an integral benchmarking workpackage, the outstanding database of the 2011 event offers the TANDEM partners the opportunity to test their numerical tools with a real case. As a prerequisite, among the numerous published seismic source models arisen from the inversion of the various available records, a couple of coseismic slip distributions have been selected to provide common initial input parameters for the tsunami computations. After possible adaptations or specific developments, the different codes are employed to simulate the Tohoku-Oki tsunami from its source to the northeast Japanese coastline. The results are tested against the numerous tsunami measurements and, when relevant, comparisons of the different codes are carried out. First, the results related to the oceanic propagation phase are compared with the offshore records. Then, the modeled coastal impacts are tested against the onshore data. Flooding at a regional scale is considered, but high resolution simulations are also performed with some of the codes. They allow examining in detail the runup amplitudes and timing, as well as the complexity of the tsunami interaction with the coastal structures. The work is supported by the Tandem project in the frame of French PIA grant ANR-11-RSNR-00023.

Population Recovery of Nicobar Long-Tailed Macaque Macaca fascicularis umbrosus following a Tsunami in the Nicobar Islands, India.

PubMed

Velankar, Avadhoot D; Kumara, Honnavalli N; Pal, Arijit; Mishra, Partha Sarathi; Singh, Mewa

2016-01-01

Natural disasters pose a threat to isolated populations of species with restricted distributions, especially those inhabiting islands. The Nicobar long tailed macaque.Macaca fascicularis umbrosus, is one such species found in the three southernmost islands (viz. Great Nicobar, Little Nicobar and Katchal) of the Andaman and Nicobar archipelago, India. These islands were hit by a massive tsunami (Indian Ocean tsunami, 26 December 2004) after a 9.2 magnitude earthquake. Earlier studies [Umapathy et al. 2003; Sivakumar, 2004] reported a sharp decline in the population of M. f. umbrosus after thetsunami. We studied the distribution and population status of M. f. umbrosus on thethree Nicobar Islands and compared our results with those of the previous studies. We carried out trail surveys on existing paths and trails on three islands to get encounter rate as measure of abundance. We also checked the degree of inundation due to tsunami by using Normalized Difference Water Index (NDWI) on landsat imageries of the study area before and after tsunami. Theencounter rate of groups per kilometre of M. f. umbrosus in Great Nicobar, Little Nicobar and Katchal was 0.30, 0.35 and 0.48 respectively with the mean group size of 39 in Great Nicobar and 43 in Katchal following the tsunami. This was higher than that reported in the two earlier studies conducted before and after the tsunami. Post tsunami, there was a significant change in the proportion of adult males, adult females and immatures, but mean group size did not differ as compared to pre tsunami. The results show that population has recovered from a drastic decline caused by tsunami, but it cannot be ascertained whether it has reached stability because of the altered group structure. This study demonstrates the effect of natural disasters on island occurring species.

Shallow water models as tool for tsunami current predictions in ports and harbors. Validation with Tohoku 2011 field data

NASA Astrophysics Data System (ADS)

Gonzalez Vida, J. M., Sr.; Macias Sanchez, J.; Castro, M. J.; Ortega, S.

2015-12-01

Model ability to compute and predict tsunami flow velocities is of importance in risk assessment and hazard mitigation. Substantial damage can be produced by high velocity flows, particularly in harbors and bays, even when the wave height is small. Besides, an accurate simulation of tsunami flow velocities and accelerations is fundamental for advancing in the study of tsunami sediment transport. These considerations made the National Tsunami Hazard Mitigation Program (NTHMP) proposing a benchmark exercise focused on modeling and simulating tsunami currents. Until recently, few direct measurements of tsunami velocities were available to compare and to validate model results. After Tohoku 2011 many current meters measurement were made, mainly in harbors and channels. In this work we present a part of the contribution made by the EDANYA group from the University of Malaga to the NTHMP workshop organized at Portland (USA), 9-10 of February 2015. We have selected three out of the five proposed benchmark problems. Two of them consist in real observed data from the Tohoku 2011 event, one at Hilo Habour (Hawaii) and the other at Tauranga Bay (New Zealand). The third one consists in laboratory experimental data for the inundation of Seaside City in Oregon. For this model validation the Tsunami-HySEA model, developed by EDANYA group, was used. The overall conclusion that we could extract from this validation exercise was that the Tsunami-HySEA model performed well in all benchmark problems proposed. The greater spatial variability in tsunami velocity than wave height makes it more difficult its precise numerical representation. The larger variability in velocities is likely a result of the behaviour of the flow as it is channelized and as it flows around bathymetric highs and structures. In the other hand wave height do not respond as strongly to chanelized flow as current velocity.

Population Recovery of Nicobar Long-Tailed Macaque Macaca fascicularis umbrosus following a Tsunami in the Nicobar Islands, India

PubMed Central

Velankar, Avadhoot D.; Kumara, Honnavalli N.

2016-01-01

Natural disasters pose a threat to isolated populations of species with restricted distributions, especially those inhabiting islands. The Nicobar long tailed macaque.Macaca fascicularis umbrosus, is one such species found in the three southernmost islands (viz. Great Nicobar, Little Nicobar and Katchal) of the Andaman and Nicobar archipelago, India. These islands were hit by a massive tsunami (Indian Ocean tsunami, 26 December 2004) after a 9.2 magnitude earthquake. Earlier studies [Umapathy et al. 2003; Sivakumar, 2004] reported a sharp decline in the population of M. f. umbrosus after thetsunami. We studied the distribution and population status of M. f. umbrosus on thethree Nicobar Islands and compared our results with those of the previous studies. We carried out trail surveys on existing paths and trails on three islands to get encounter rate as measure of abundance. We also checked the degree of inundation due to tsunami by using Normalized Difference Water Index (NDWI) on landsat imageries of the study area before and after tsunami. Theencounter rate of groups per kilometre of M. f. umbrosus in Great Nicobar, Little Nicobar and Katchal was 0.30, 0.35 and 0.48 respectively with the mean group size of 39 in Great Nicobar and 43 in Katchal following the tsunami. This was higher than that reported in the two earlier studies conducted before and after the tsunami. Post tsunami, there was a significant change in the proportion of adult males, adult females and immatures, but mean group size did not differ as compared to pre tsunami. The results show that population has recovered from a drastic decline caused by tsunami, but it cannot be ascertained whether it has reached stability because of the altered group structure. This study demonstrates the effect of natural disasters on island occurring species. PMID:26886197

Effects of the 26 December 2004 Indian Ocean Tsunami in the Republic of Seychelles

NASA Astrophysics Data System (ADS)

Jackson, L. E.; Barrie, J. V.; Forbes, D. L.; Shaw, J.; Manson, G. K.; Schmidt, M.

2005-12-01

The Dec. 26, 2004 Indian Ocean tsunami impacted Mahé and Praslin islands as a sequence of waves at intervals of tens of minutes to hours. The first tsunami wave struck at low tide, but others occurred through several tidal cycles, so that some subsequent waves arrived at high tide. The first indication of the tsunami on the Mahé tide gauge (sampling interval 4 minutes) was a rise in water level to lower than higher high water at large tides between 08:08 and 08:12 UTC(between 12:08 and 12:12 local time). This was followed by a maximum withdrawal of water in all areas. This level was not recorded by the tide gauge at Mahé, because the stilling well went dry, but evidence from observers indicates that it dropped as much as 4 m below mean sea level. The subsequent highest water levels, highest run-ups, and maximum distances inland that tsunami flooding reached were in coastal lowlands generally facing east toward the source of the tsunami. The highest flood levels on Mahé ranged from ~1.6 m to >4.4 m above mean sea level. On Praslin, they ranged from ~1.8 m to 3.6 m. The shallow (<200 m) shelf platform surrounding the granitic islands played an important role in determining the tsunami wave direction and amplitude at the shoreline. The shoaling waves were refracted, causing them to approach the islands from various directions, and amplified so as to cause higher run-up in specific coastal embayments. Consequently, tsunami inundation and damage were not confined to east-facing shores. Run-up and damage were locally as severe along shores of Mahé and Praslin facing away from the source of the tsunami. Some observers on the west sides of both islands reported water approaching from two directions (northwest and southeast). Furthermore, the timing of maximum inundation varied around the archipelago as tsunami waves arrived at different times in the tidal cycle: the maximum inundation at Anse-à-la-Mouche (on the west side of Mahé) occurred about 4 hours after the initial tsunami wave reached the archipelago, whereas the highest water level in the city of Victoria (on the northeast side of Mahé) occurred about 16 hours after the first arrival (but with much lower wave energy). Damage to public works was greatest in the Victoria area. Lateral spread failures developed in artificial fills forming the fishing port. Liquefaction was induced in these fills by cyclic inundation, saturation and rapid draw-down. Washouts occurred on two sections of highway causeway crossing reclaimed land south of Victoria due to the rapid drainage of tsunami floodwaters. Similar erosion caused structural failure of hotel buildings on Praslin. Elsewhere, the greatest damage was coincident with preexisting modification of the coast by development including: removal of natural beach berms, construction of hotel structures adjacent to the high-water mark or seaward over the beach, and placement of roads immediately adjacent to beaches. The damaging effects of the tsunami were confined to the granitic islands of Seychelles archipelago. The lack of impact on the atolls is due to the deep water surrounding them: this resulted in minimal shoaling and amplification of the long wavelength and low-amplitude tsunami waves.

Scenarios for earthquake-generated tsunamis on a complex tectonic area of diffuse deformation and low velocity: The Alboran Sea, Western Mediterranean

USGS Publications Warehouse

Alvarez-Gomez, J. A.; Aniel-Quiroga, I.; Gonzalez, M.; Olabarrieta, Maitane; Carreno, E.

2011-01-01

The tsunami impact on the Spanish and North African coasts of the Alboran Sea generated by several reliable seismic tsunamigenic sources in this area was modeled. The tectonic setting is complex and a study of the potential sources from geological data is basic to obtain probable source characteristics. The tectonic structures considered in this study as potentially tsunamigenic are: the Alboran Ridge associated structures, the Carboneras Fault Zone and the Yusuf Fault Zone. We characterized 12 probable tsunamigenic seismic sources in the Alboran Basin based on the results of recent oceanographical studies. The strain rate in the area is low and therefore its seismicity is moderate and cannot be used to infer characteristics of the major seismic sources. These sources have been used as input for the numerical simulation of the wave propagation, based on the solution of the nonlinear shallow water equations through a finite-difference technique. We calculated the Maximum Wave Elevations, and Tsunami Travel Times using the numerical simulations. The results are shown as maps and profiles along the Spanish and African coasts. The sources associated with the Alboran Ridge show the maximum potential to generate damaging tsunamis, with maximum wave elevations in front of the coast exceeding 1.5 m. The Carboneras and Yusuf faults are not capable of generating disastrous tsunamis on their own, although their proximity to the coast could trigger landslides and associated sea disturbances. The areas which are more exposed to the impact of tsunamis generated in the Alboran Sea are the Spanish coast between Malaga and Adra, and the African coast between Alhoceima and Melilla.

Washington Tsunami Hazard Mitigation Program

NASA Astrophysics Data System (ADS)

Walsh, T. J.; Schelling, J.

2012-12-01

Washington State has participated in the National Tsunami Hazard Mitigation Program (NTHMP) since its inception in 1995. We have participated in the tsunami inundation hazard mapping, evacuation planning, education, and outreach efforts that generally characterize the NTHMP efforts. We have also investigated hazards of significant interest to the Pacific Northwest. The hazard from locally generated earthquakes on the Cascadia subduction zone, which threatens tsunami inundation in less than hour following a magnitude 9 earthquake, creates special problems for low-lying accretionary shoreforms in Washington, such as the spits of Long Beach and Ocean Shores, where high ground is not accessible within the limited time available for evacuation. To ameliorate this problem, we convened a panel of the Applied Technology Council to develop guidelines for construction of facilities for vertical evacuation from tsunamis, published as FEMA 646, now incorporated in the International Building Code as Appendix M. We followed this with a program called Project Safe Haven (http://www.facebook.com/ProjectSafeHaven) to site such facilities along the Washington coast in appropriate locations and appropriate designs to blend with the local communities, as chosen by the citizens. This has now been completed for the entire outer coast of Washington. In conjunction with this effort, we have evaluated the potential for earthquake-induced ground failures in and near tsunami hazard zones to help develop cost estimates for these structures and to establish appropriate tsunami evacuation routes and evacuation assembly areas that are likely to to be available after a major subduction zone earthquake. We intend to continue these geotechnical evaluations for all tsunami hazard zones in Washington.

Maritime Tsunami Hazard Assessment in California

NASA Astrophysics Data System (ADS)

Lynett, P. J.; Borrero, J. C.; Wilson, R. I.; Miller, K. M.

2012-12-01

The California tsunami program in cooperation with NOAA and FEMA has begun implementing a plan to increase awareness of tsunami generated hazards to the maritime community (both ships and harbor infrastructure) through the development of in-harbor hazard maps, offshore safety zones for boater evacuation, and associated guidance for harbors and marinas before, during and following tsunamis. The hope is that the maritime guidance and associated education and outreach program will help save lives and reduce exposure of damage to boats and harbor infrastructure. An important step in this process is to understand the causative mechanism for damage in ports and harbors, and then ensure that the models used to generate hazard maps are able to accurately simulate these processes. Findings will be used to develop maps, guidance documents, and consistent policy recommendations for emergency managers and port authorities and provide information critical to real-time decisions required when responding to tsunami alert notifications. Basin resonance and geometric amplification are two reasonably well understood mechanisms for local magnification of tsunami impact in harbors, and are generally the mechanisms investigated when estimating the tsunami hazard potential in a port or harbor. On the other hand, our understanding of and predictive ability for currents is lacking. When a free surface flow is forced through a geometric constriction, it is readily expected that the enhanced potential gradient will drive strong, possibly unstable currents and the associated turbulent coherent structures such as "jets" and "whirlpools"; a simple example would be tidal flow through an inlet channel. However, these fundamentals have not been quantitatively connected with respect to understanding tsunami hazards in ports and harbors. A plausible explanation for this oversight is the observation that these features are turbulent phenomena with spatial and temporal scales much smaller than that of a typical tsunami. The ability to model and then validate these currentsdissect them has only recently become available through the evaluation of dozens of eyewitness accounts and hundreds of videos.developed. In this presentation, we will present ongoing work related to the application of such models to quantify the maritime tsunami hazard in select ports and harbors in California. The development of current-based tsunami hazard maps and safe-offshore-depth delineations will be discussed. We will also present an overview of the challenges in modeling tsunami currents, including capture of turbulent dynamics, coupling with tides, and issues with long-duration simulations. This work in California will form the basis for tsunami hazard reduction for all U.S. maritime communities through the National Tsunami Hazard Mitigation Program.

2011 Tohoku tsunami runup hydrographs, ship tracks, upriver and overland flow velocities based on video, LiDAR and AIS measurements

NASA Astrophysics Data System (ADS)

Fritz, H. M.; Phillips, D. A.; Okayasu, A.; Shimozono, T.; Liu, H.; Takeda, S.; Mohammed, F.; Skanavis, V.; Synolakis, C.; Takahashi, T.

2014-12-01

The 2004 Indian Ocean tsunami marked the advent of survivor videos mainly from tourist areas in Thailand and basin-wide locations. Near-field video recordings on Sumatra's north tip at Banda Aceh were limited to inland areas a few kilometres off the beach (Fritz et al., 2006). The March 11, 2011, magnitude Mw 9.0 earthquake off the Tohoku coast of Japan caused catastrophic damage and loss of life resulting in the costliest natural disaster in recorded history. The mid-afternoon tsunami arrival combined with survivors equipped with cameras on top of vertical evacuation buildings provided numerous inundation recordings with unprecedented spatial and temporal resolution. High quality tsunami video recording sites at Yoriisohama, Kesennuma, Kamaishi and Miyako along Japan's Sanriku coast were surveyed, eyewitnesses interviewed and precise topographic data recorded using terrestrial laser scanning (TLS). The original video recordings were recovered from eyewitnesses and the Japanese Coast Guard (JCG). The analysis of the tsunami videos follows an adapted four step procedure (Fritz et al., 2012). Measured overland flow velocities during tsunami runup exceed 13 m/s at Yoriisohama. The runup hydrograph at Yoriisohama highlights the under sampling at the Onagawa Nuclear Power Plant (NPP) pressure gauge, which skips the shorter period second crest. Combined tsunami and runup hydrographs are derived from the videos based on water surface elevations at surface piercing objects and along slopes identified in the acquired topographic TLS data. Several hydrographs reveal a draw down to minus 10 m after a first wave crest exposing harbor bottoms at Yoriisohama and Kamaishi. In some cases ship moorings resist the main tsunami crest only to be broken by the extreme draw down. A multi-hour ship track for the Asia Symphony with the vessels complete tsunami drifting motion in Kamaishi Bay is recovered from the universal ship borne AIS (Automatic Identification System). Multiple hydrographs corroborate the tsunami propagation through Miyako Bay and up the Hei River. Tsunami outflow currents up to 11 m/s were measured in Kesennuma Bay making navigation impossible. Further we discuss the complex effects of coastal structures on inundation and outflow hydrographs as well as associated flow velocities.

Potential Flooding area for local Tsunami in Nayarit Region (Western Coast of Mexico).

NASA Astrophysics Data System (ADS)

Trejo-Gomez, E.; Ortiz, M.; Nuñez-Cornu, F. J.

2016-12-01

The western coast of Mexico in the region of Jalisco and Nayarit states has a complex tectonics and a high seismic activity. In the last century, four big tsunamis occurred in this area, (three of them in 1932 and one in 1995, that hit the coast of Colima, Jalisco and Nayarit. Three of these tsunamis were generated by earthquakes and one more (22 June 1932) by an underwater landslide. Currently, there is a seismic Gap on the north coast of Jalisco and southern Nayarit. Recent published papers (Urías-Espinosa et al, 2016) and the first results of TsuJal Project (Núñez- Cornú et al, 2016) suggest that subduction regime to the north of Cabo Corrientes changes and the Rivera plate subducts with a very low angle and this structure remains until Maria Madre Island at north of the Marias Islands. The hypothesis of this work is the estimation of the tsunami run up and the flooding zone after a great magnitude earthquake generated by the rupture of the hypothetical subduction structure north of Cabo Corrientes. The possible effects on the coasts of Nayarit, Islas Marias and Banderas Bay (Puerto Vallarta) are proposed in this study.

14 CFR 25.529 - Hull and main float landing conditions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and main float landing conditions. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.529 Hull and main.... (b) Unsymmetrical landing for hull and single float seaplanes. Unsymmetrical step, bow, and stern...

A possible source mechanism of the 1946 Unimak Alaska far-field tsunami, uplift of the mid-slope terrace above a splay fault zone

USGS Publications Warehouse

von Huene, Roland E.; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter

2016-01-01

In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of “tsunami” earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

Imaging, radio, and modeling results pertaining to the ionospheric signature of the 11 March 2011 tsunami over the Pacific Ocean

NASA Astrophysics Data System (ADS)

Makela, J. J.; Lognonne, P.; Occhipinti, G.; Hebert, H.; Gehrels, T.; Coisson, P.; Rolland, L. M.; Allgeyer, S.; Kherani, A.

2011-12-01

The Mw=9.0 earthquake that occurred off the east coast of Honshu, Japan on 11 March 2011 launched a tsunami that traveled across the Pacific Ocean, in turn launching vertically propagating atmospheric gravity waves. Upon reaching 250-350 km in altitude, these waves impressed their signature on the thermosphere/ionosphere system. We present observations of this signature obtained using a variety of radio instruments and an imaging system located on the islands of Hawaii. These measurements represent the first optical images recorded of the airglow signature resulting from the passage of a tsunami. Results from these instruments clearly show wave structure propagating in the upper atmosphere with the same velocity as the ocean tsunami, emphasizing the coupled nature of the ocean, atmosphere, and ionosphere. Modeling results are also presented to highlight current understandings of this coupling process.

Study on design method and vibration reduction characteristic of floating raft with periodic structure

NASA Astrophysics Data System (ADS)

Fang, Yuanyuan; Zuo, Yanyan; Xia, Zhaowang

2018-03-01

The noise level is getting higher with the development of high-power marine power plant. Mechanical noise is one of the most obvious noise sources which not only affect equipment reliability, riding comfort and working environment, but also enlarge underwater noise. The periodic truss type device which is commonly applied in fields of aerospace and architectural is introduced to floating raft construction in ship. Four different raft frame structure are designed in the paper. The vibration transmissibility is taken as an evaluation index to measure vibration isolation effect. A design scheme with the best vibration isolation effect is found by numerical method. Plate type and the optimized periodic truss type raft frame structure are processed to experimental verify vibration isolation effect of the structure of the periodic raft. The experimental results demonstrate that the same quality of the periodic truss floating raft has better isolation effect than that of the plate type floating raft.

A Tsunami Model for Chile for (Re) Insurance Purposes

NASA Astrophysics Data System (ADS)

Arango, Cristina; Rara, Vaclav; Puncochar, Petr; Trendafiloski, Goran; Ewing, Chris; Podlaha, Adam; Vatvani, Deepak; van Ormondt, Maarten; Chandler, Adrian

2014-05-01

Catastrophe models help (re)insurers to understand the financial implications of catastrophic events such as earthquakes and tsunamis. In earthquake-prone regions such as Chile,(re)insurers need more sophisticated tools to quantify the risks facing their businesses, including models with the ability to estimate secondary losses. The 2010 (M8.8) Maule (Chile) earthquake highlighted the need for quantifying losses from secondary perils such as tsunamis, which can contribute to the overall event losses but are not often modelled. This paper presents some key modelling aspects of a new earthquake catastrophe model for Chile developed by Impact Forecasting in collaboration with Aon Benfield Research partners, focusing on the tsunami component. The model has the capability to model tsunami as a secondary peril - losses due to earthquake (ground-shaking) and induced tsunamis along the Chilean coast are quantified in a probabilistic manner, and also for historical scenarios. The model is implemented in the IF catastrophe modelling platform, ELEMENTS. The probabilistic modelling of earthquake-induced tsunamis uses a stochastic event set that is consistent with the seismic (ground shaking) hazard developed for Chile, representing simulations of earthquake occurrence patterns for the region. Criteria for selecting tsunamigenic events (from the stochastic event set) are proposed which take into consideration earthquake location, depth and the resulting seabed vertical displacement and tsunami inundation depths at the coast. The source modelling software RuptGen by Babeyko (2007) was used to calculate static seabed vertical displacement resulting from earthquake slip. More than 3,600 events were selected for tsunami simulations. Deep and shallow water wave propagation is modelled using the Delft3D modelling suite, which is a state-of-the-art software developed by Deltares. The Delft3D-FLOW module is used in 2-dimensional hydrodynamic simulation settings with non-steady flow. Earthquake-induced static seabed vertical displacement is used as an input boundary condition to the model. The model is hierarchically set up with three nested domain levels; with 250 domains in total covering the entire Chilean coast. Spatial grid-cell resolution is equal to the native SRTM resolution of approximately 90m. In addition to the stochastic events, the 1960 (M9.5) Valdivia and 2010 (M8.8) Maule earthquakes are modelled. The modelled tsunami inundation map for the 2010 Maule event is validated through comparison with real observations. The vulnerability component consists of an extensive damage curves database, including curves for buildings, contents and business interruption for 21 occupancies, 24 structural types and two secondary modifies such as building height and period of construction. The building damage curves are developed by use of load-based method in which the building's capacity to resist tsunami loads is treated as equivalent to the design earthquake load capacity. The contents damage and business interruption curves are developed by use of deductive approach i.e. HAZUS flood vulnerability and business function restoration models are adapted for detailed occupancies and then assigned to the dominant structural types in Chile. The vulnerability component is validated through model overall back testing by use of observed aggregated earthquake and tsunami losses for client portfolios for 2010 Maule earthquake.

The February 27, 2010 Chile Tsunami - Sedimentology of runup and backflow deposits at Isla Mocha

NASA Astrophysics Data System (ADS)

Bahlburg, H.; Spiske, M.

2010-12-01

On February 27, 2010, at 3:34 am local time, an earthquake with Mw 8.8 occurred off the town of Constitución in Central Chile and caused a major tsunami beween Valaparaiso (c. 33°S) and Tirua (c. 38°S). Maximum runup heights of up to 10 m were measured on coastal plains. The cliff coast at Tirua recorded a runup height between 30 m and 40 m. Considering past tsunami events, respective deposits may be the only observable evidence, even though their preservation potential is limited. To understand how tsunami deposits form and how they can be identified in the geological record, it is of paramount importance to undertake detailed studies in the wake of such events. Here we report initial field data of a sedimentological post-tsunami field survey undertaken in Central Chile between March 31 and April 18, 2010. At selected localities we measured detailed topographic profiles including runup heights and inundation distances, and recorded the thickness, distribution and sedimentological features of the respective tsunami deposits, as well as erosional features caused by the tsunami. We found the most instructive and complete sedimentological record of the February 27, 2010 tsunami at the northern tip of Isla Mocha, a small island off the Chilean coast at c. 28.15°S. Runup distances vary between 400 m and 600 m, the flow depth exceeded 3 m at ca. 100 m from the coast. Runup heights reached up to 21 m above sea level. In a rare sedimentological case, deposits of tsunami runup and backwash could be distinguished. The runup phase was mainly documented by fields of boulders extending c. 360 m inland. Boulders had maximum weights of 12 t. They were oriented with their long axis parallel to the coast and the wave front. Algal veneers and barnacles on the boulder faces give evidence of entrainment in intertidal water depths. The boulders are now embedded in mostly structureless coarse shelly sand. These sands were originally entrained during near shore supratidal erosion of coastal plain terraces by the tsunami and transported inland during runup. Flow structures indicate that the sands were then re-deposited during backwash. Downcurrent of terrace steps the tsunami backwash produced large erosional gullies. The backwash deposits occur either as widespread covers blanketing microtopography consisting of dark pre-tsunami soils, or as depositional fans which prograde seaward over soils free of a sediment cover. The coarse to very coarse shell debris is comprised of fragmented or entire mollusk and crab cascs. Some coarser deposits also contain significant amounts of Tertiary sandstone bedrock gravels in parts freshly eroded by the tsunami. The deposits are either massive or imbricated, the imbrication identifying them as a product of backflow currents. The deposit thickness is commonly c. 10 to 15 cm. Around large boulders backflow partitioning and associated erosion and deposition permitted the generation of 0.8 m deep scours and accumulation of up to 80 cm thick backflow sands. The depositional angles at the fan fronts vary between 27° and 36°. Backflow fan surfaces are characterized by channel and overbank regions and flow structures like current ripples. Clusters of bedrock pebbles and mollusk cascs are distributed irregularly over the fan surfaces.

The occurrence of extreme events a tsunami and storm deposit in Chilcatay formation, Ica, Peru.

NASA Astrophysics Data System (ADS)

Poma Porras, O. A.; Cayo, R., Jr.; Casas, N.; Figueroa, F.

2016-12-01

The Chilcatay Formation (Oligocene to middle Miocene) south of Peru is in the Pisco Basin contains a thick sequence of Cenozoic sediments that record at least three marine transgressions characterized by successions of fine sandstones, siltstones, and diatomaceous mudstones. The sequence records certain facies that are typical of high-energy events, including extreme storms, tsunamis and earthquakes. The studied deposit is characterized by the presence of two layers of varying thickness. The lower layer, which is in markedly erosive contact with the underlying layer, is a very coarse-grained sandstone, highly sorted and with subrounded to subangular grains. The thickness varies laterally from one to 50 cm. The top layer, which is 40-60 cm thick and exposed for approximately 200 m, consists of a dense matrix of coarse-grained size fragments of molluscs (oysters), barnacles, and lithoclasts. The biogenic matrix contains many igneous (gabbro, granite) and metamorphic cobbles and boulders, and lithic tuffs, clusters of barnacles, and fragments consisting of vermetid gastropods reefs. The abundant igneous and metamorphic cobbles and boulders are rounded and subrounded, with a larger diameter between 3 and 140 cm, and occurring at a density of 3-8 clasts by square meter. The lithic tuffs are subrounded, have an ovoid morphology and a greater diameter between 1 and 44 cm. All these clasts occur scattered and 'floating' in the bioclastic matrix. The characteristics of the studied layer suggest that it was deposited by an extreme event that eroded the area between shoreface and backshore redepositing the materials and leaving a chaotic facies distribution with cobbles and boulders of different lithology. The large waves caused heavy erosion of the sediments in the shallow seafloor and the basement, mixing the biogenic and lithogenic clasts. The large size of these clasts suggests that such an event may have been a tsunami.

REASSESSMENT OF TSUNAMI HAZARD IN THE CITY OF IQUIQUE, CHILE, AFTER THE PISAGUA EARTHQUAKE OF APRIL 2014 In the present contribution, we will reassess the tsunami hazard for the North of Chile taking into account the occurrence of the recent events, focusing on the potential tsunami impact that a worse case scenario could produce in the city of Iquique.

NASA Astrophysics Data System (ADS)

Cienfuegos, R.; Suarez, L.; Aránguiz, R.; Gonzalez, G.; González-Carrasco, J. F.; Catalan, P. A.; Dominguez, J. C.; Tomita, T.

2014-12-01

On April 1st2014 a 8.1 Mw Earthquake occurred at 23:46:50 UTC (20:46:50 local time) with its epicenter located off the coast of Pisagua, 68 km north of the city of Iquique (An et al., 2014). The potential risk of earthquake and tsunami in this area was widely recognized by the scientific community (Chlieh et al., 2004). Nevertheless, the energy released by this earthquake and the associated slip distribution was much less than expected. In the present contribution, we will reassess the tsunami hazard for the North of Chile taking into account the occurrence of the recent events, focusing on the potential impact that a worse case scenario could produce in the city of Iquique. For that purpose, an updated tsunami source will be derived using updated information on the seismic and co-seismic tectonic displacements that is available from historical, geological information, and the dense GPS and seismometer networks available in the North of Chile. The updated tsunami source will be used to generate initial conditions for a tsunami and analyze the following aspects: i) large scale hydrodynamics, ii) arrival times, maximum flow depths, and inundation area, iii) potential impact on the port of Iquique, and more specifically on the container's drift that the tsunami could produce. This analysis is essential to reassess tsunami hazard in Iquique, evaluate evacuation plans and mitigation options regarding the port operation. Tsunami propagation and inundation will be conducted using the STOC model (Tomita and Honda, 2010), and a high resolution Lidar topographic database. ReferencesAn, C. et al. (2014). Tsunami source and its validation of the 2014 Iquique, Chile Earthquake, Geophys. Res. Lett., 41, doi:10.1002/2014GL060567. Chlieh, et al. (2004). Crustal deformation and fault slip during the seismic cycle in the north Chile subduction zone, from GPS and INSAR observations, Geophys J. Int., 158(2), 695-711, 10.1111/j.1365-246X.2004.02326.x. Tomita, T., & Honda, K. (2010). Practical model to estimate drift motion of vessels by tsunami with consideration of colliding with structures and stranding. Proceedings of the 32nd Conference on Coastal Engineering. ASCE.

New contributions to the debate on the cause of the January 11th, 1693 tsunami in eastern Sicily (Italy): earthquake or offshore landslide source (or may be both)?

NASA Astrophysics Data System (ADS)

Armigliato, A.; Tinti, S.; Zaniboni, F.; Pagnoni, G.; Argnani, A.

2007-12-01

Eastern Sicily is among the most exposed regions in Italy and in the whole Mediterranean to tsunami hazard and risk. The historical tsunamis recorded here were generally associated to moderate-to-large magnitude earthquakes. The largest tsunami documented in the area occurred on January 11th, 1693. It followed the highest-magnitude earthquake (7.4) of the Italian seismic history. The tsunami, whose first significant motion was a retreat along the entire eastern Sicily coastline, produced the most devastating effects at Augusta (15 meters run-up) and Catania, being relevant at Siracusa and Messina too. A lively debate exists on whether the earthquake was the only source of the tsunami, or other causes (such as submarine landslides, possibly triggered by the earthquake) contributed to the tsunami generation. In the framework of the EC funded project TRANSFER, we investigate both hypotheses, starting from suitable onshore and offshore faults as well as from offshore landslide bodies, and hence simulating numerically the ensuing tsunami and comparing the results with the available historical information. We base on the results obtained during recent offshore surveys, in particular the multichannel seismic survey MESC2001, carried out in year 2001 on board the R/V Urania of the Italian National Council of Researches (CNR), which mapped both active normal faults and a number of possible landslide bodies along the Hyblaean-Malta escarpment, the most prominent tectonic structure found just few kilometres offshore eastern Sicily. From the modelling point of view, the initial condition for the earthquake- generated tsunamis coincides with the vertical coseismic deformation of the seafloor. Instead, the landslide motion is simulated through the Lagrangian block model UBO-BLOCK2, developed at the University of Bologna. Finally, the finite-element code UBO-TSUFE, implemented by the same research team, is used to simulate the tsunami generation and propagation. The main conclusions are: 1) if the earthquake is postulated to be the only responsible for the tsunami, then the historical information can be reproduced only by assuming an offshore tectonic source; 2) taking into account the largest of the mapped landslides, we are able to reproduce quite satisfactorily both the first polarity and the size distribution of the tsunami; 3) we cannot rule out the idea that there was a concurrent contribution of the earthquake and of the landslide in generating the tsunami.

14 CFR 25.531 - Hull and main float takeoff condition.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and main float takeoff condition. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.531 Hull and main float takeoff condition. For the wing and its attachment to the hull or main float— (a) The aerodynamic...

Sensitivity of Tsunami Waves and Coastal Inundation/Runup to Seabed Displacement Models: Application to the Cascadia Subduction zone

NASA Astrophysics Data System (ADS)

Jalali Farahani, R.; Fitzenz, D. D.; Nyst, M.

2015-12-01

Major components of tsunami hazard modeling include earthquake source characterization, seabed displacement, wave propagation, and coastal inundation/run-up. Accurate modeling of these components is essential to identify the disaster risk exposures effectively, which would be crucial for insurance industry as well as policy makers to have tsunami resistant design of structures and evacuation planning (FEMA, 2008). In this study, the sensitivity and variability of tsunami coastal inundation due to Cascadia megathrust subduction earthquake are studied by considering the different approaches for seabed displacement model. The first approach is the analytical expressions that were proposed by Okada (1985, 1992) for the surface displacements and strains of rectangular sources. The second approach was introduced by Meade (2006) who introduced analytical solutions for calculating displacements, strains, and stresses on triangular sources. In this study, the seabed displacement using triangular representation of geometrically complex fault surfaces is compared with the Okada rectangular representations for the Cascadia subduction zone. In the triangular dislocation algorithm, the displacement is calculated using superposition of two angular dislocations for each of the three triangle legs. The triangular elements could give a better and gap-free representation of the fault surfaces. In addition, the rectangular representation gives large unphysical vertical displacement along the shallow-depth fault edge that generates unrealistic short-wavelength waves. To study the impact of these two different algorithms on the final tsunami inundation, the initial tsunami wave as well as wave propagation and the coastal inundation are simulated. To model the propagation of tsunami waves and coastal inundation, 2D shallow water equations are modeled using the seabed displacement as the initial condition for the numerical model. Tsunami numerical simulation has been performed on high-resolution bathymetric/topographic computational grids to identify accurate tsunami impact and flooding limits for the west of USA.

Field Survey of the 2011 Tohoku Tsunami in Fukushima

NASA Astrophysics Data System (ADS)

Yeh, H. H.; Sato, S.; Tajima, Y.; Okayasu, A.; Fritz, H. M.

2012-12-01

On March 11, 2011, a magnitude Mw 9.0 earthquake struck the coast of Japan's Tohoku region causing loss of life and catastrophic damage. The infamous nuclear accident at Fukushima Dai-Ichi Nuclear Power Plant occurred immediately after the event. The earthquake and tsunami flooding of the nuclear power plant resulted in a series of equipment failures, nuclear meltdowns, and releases of radioactive materials. Because of the sudden impact of the accident, all the residents had to vacate the area within a 20 km radius from the NPP. Consequently, no tsunami survey had been permitted in the restricted area. Likewise debris removal and reconstruction had been widely postponed. In February 2012, almost eleven months later, a small group of tsunami scientists entered the exclusion zone with a special permit and surveyed tsunami effects along this 40 km stretch of coastline for the first time. The recent partial lift of the access restriction allowed more detailed follow-up surveys in June and August 2012. Here we report tsunami runup measurements along the Fukushima coasts where the data had been absent. The envelope of the tsunami runup heights along the coast was found to be approximately at the level of 13 m T.P. (Tokyo Peil), while a localized maximum runup of 21.1 m T.P. was measured on a coastal bluff 8.5 km south of the nuclear power plant. The runup pattern along the restricted Fukushima coast is consistent with the interpolation from the runup values previously measured outside of the restricted area. We also discuss the persistence of observed tsunami effects that remained in the environment given the human absence for almost one full year: included are the damage patterns of coastal structures, geomorphologic changes, and tsunami deposits.; A scene of Tomioka Fishing Port: 9 km south of the Fukushima Dai-Ichi NPP.

Experimental Study on Tsunami Risk Reduction on Coastal Building Fronted by Sea Wall

PubMed Central

Khan, M. T. R.; Shirazi, S. M.

2014-01-01

This experimental study was conducted to idealize the efficacy of sea wall in controlling the tsunami forces on onshore structures. Different types of sea walls were placed in front of the building model. The tsunami forces and the wave heights were measured with and without the sea wall conditions. Types of sea wall, wall height, and wall positions were varied simultaneously to quantify the force reductions. Maximum of 41% forces was reduced by higher sea wall, positioned closer proximity to the model whereas this reduction was about 27% when the wall height was half of the high wall. Experimental investigations revealed that wall with adequate height and placed closer to the structures enables a satisfactory predictor of the force reduction on onshore structures. Another set of tests were performed with perforated wall placing near the building model. Less construction cost makes the provision of perforated sea wall interesting. The overall results showed that the efficacy of perforated wall is almost similar to solid wall. Hence, it can be efficiently used instead of solid wall. Moreover, overtopped water that is stuck behind the wall is readily gone back to the sea through perforations releasing additional forces on the nearby structures. PMID:24790578

Evaluation of the Relationship Between Coral Damage and Tsunami Dynamics; Case Study: 2009 Samoa Tsunami

NASA Astrophysics Data System (ADS)

Dilmen, Derya I.; Titov, Vasily V.; Roe, Gerard H.

2015-12-01

On September 29, 2009, an Mw = 8.1 earthquake at 17:48 UTC in Tonga Trench generated a tsunami that caused heavy damage across Samoa, American Samoa, and Tonga islands. Tutuila island, which is located 250 km from the earthquake epicenter, experienced tsunami flooding and strong currents on the north and east coasts, causing 34 fatalities (out of 192 total deaths from this tsunami) and widespread structural and ecological damage. The surrounding coral reefs also suffered heavy damage. The damage was formally evaluated based on detailed surveys before and immediately after the tsunami. This setting thus provides a unique opportunity to evaluate the relationship between tsunami dynamics and coral damage. In this study, estimates of the maximum wave amplitudes and coastal inundation of the tsunami are obtained with the MOST model (T itov and S ynolakis, J. Waterway Port Coast Ocean Eng: pp 171, 1998; T itov and G onzalez, NOAA Tech. Memo. ERL PMEL 112:11, 1997), which is now the operational tsunami forecast tool used by the National Oceanic and Atmospheric Administration (NOAA). The earthquake source function was constrained using the real-time deep-ocean tsunami data from three DART® (Deep-ocean Assessment and Reporting for Tsunamis) systems in the far field, and by tide-gauge observations in the near field. We compare the simulated run-up with observations to evaluate the simulation performance. We present an overall synthesis of the tide-gauge data, survey results of the run-up, inundation measurements, and the datasets of coral damage around the island. These data are used to assess the overall accuracy of the model run-up prediction for Tutuila, and to evaluate the model accuracy over the coral reef environment during the tsunami event. Our primary findings are that: (1) MOST-simulated run-up correlates well with observed run-up for this event ( r = 0.8), it tends to underestimated amplitudes over coral reef environment around Tutuila (for 15 of 31 villages, run-up is underestimated by more than 10 %; in only 5 was run-up overestimated by more than 10 %), and (2) the locations where the model underestimates run-up also tend to have experienced heavy or very heavy coral damage (8 of the 15 villages), whereas well-estimated run-up locations characteristically experience low or very low damage (7 of 11 villages). These findings imply that a numerical model may overestimate the energy loss of the tsunami waves during their interaction with the coral reef. We plan future studies to quantify this energy loss and to explore what improvements can be made in simulations of tsunami run-up when simulating coastal environments with fringing coral reefs.

Paleographical, Bathymetric and Numerical Investigations for a Tsunami Possibly Caused by Submarine Mass Failure in the Nankai Trough, Japan

NASA Astrophysics Data System (ADS)

Baba, T.; Ashi, J.; Kanamatsu, T.; Imai, K.; Yamashita, K.

2017-12-01

"SHINCHO-KI" is an ancient document that records tsunami damages caused by the 1512 Eisho earthquake, the 1605 Keicho earthquake, the 1707 Hoei earthquake and the 1854 Ansei-Nankai earthquake in Shishikui, where is located along the coast of the southeastern part of Shikoku, facing to the Nankai trough. According to SHINCHO-KI, 3700 people were dead in Shishikui by the tsunami during the 1512 Eisho earthquake. However, no evidence was found for the occurrence of the 1512 Eisho earthquake except for SHINCHO-KI, while the other earthquakes were recorded in many ancient documents in the southwestern Japan. To investigate the source mechanism of the 1512 Eisho earthquake, we carefully read a bathymetric chart and found a scarp with a height of about 400 m and a width of about 6000 m at a position about 24 km offshore in the southeastern direction from Shishikui. We also carried out a survey by using a deep-towed sub-bottom profiler (SBP) on ROV NSS during the R/V Hakuho-maru KH-16-5 cruise. The result shows detailed structures possibly caused by a recent landslide. The vertical displacement of the strata was measured to be about 50 m. By considering these results, we simulated the 1512 Eisho tsunami generated by a submarine mass failure. The topographic data in Shishikui which is needed in the calculation was made from the present data. But we removed the artificial structures such as wave breakers and altered coastlines by referring to old map images. In the numerical simulation, the initial sea surface deformation was obtained by the method proposed by Watts et al. (2005), and the tsunami propagation was calculated by solving the nonlinear shallow water equations with dispersive (Boussinesq) term on a finite difference scheme. We solved the advection terms by using the third-order upwind difference to avoid artificial viscosity. The numerical simulation estimated the maximum tsunami height of about 6m and moderate inundation on land in Shishikui by the 1512 Eisho tsunami.

Geologic evidence northeast of Puerto Rico for an Atlantic tsunami in the last 500 years

NASA Astrophysics Data System (ADS)

Atwater, B. F.; Tuttle, M. P.

2008-12-01

A historical tsunami of undetermined origin best explains a suite of probably related features at Anegada, British Virgin Islands: shore-normal scours, fields of cobbles and boulders, a horizon of sand and shell, and salt ponds. Anegada's exposed location and low-lying landscape make the island a natural tsunami recorder. Facing the Puerto Rico Trench at the northeast corner of the Caribbean, barely 10 km from the top of the continental slope, Anegada can receive tsunamis almost directly from the open North Atlantic. The island's highest ground consists of a limestone platform that crests 8 m above sea level. Many of Anegada's shores adjoin beach ridges, composed of distinctively pink bioclastic sand, that stand less than 5 m above sea level. Behind the ridges are salt ponds that rarely rise above high tide levels of the surrounding sea. The island's name, coined in 1493 during Columbus's second voyage, means "drowned." Local eyewitnesses to Hurricane Donna, at category 4 when its eye crossed Anegada in 1960, recounted no storm-caused versions of the following features: SCOURS. Dozens of coast-normal scours cut across beach ridges of the island's north-central shore. The largest of them holds a pond 200 m long and a few tens of meters wide. The scours are better explained by overwash of the ridges than by inheritance of any pre-existing carbonate landform; they differ in size and shape from spurs and grooves of the island's barrier reef and from the sinkholes of the limestone platform. More than one time of overwash is permitted by differences among the headward limits of the scours. COBBLES AND BOULDERS. Inland from the scours, as much as 1 km inland of Anegada's north-central shore, fields of limestone cobbles and boulders extend tens of meters southward from limestone knolls. Like the scours, they imply overwash from the north. SAND AND SHELL BED. An event horizon as much as 25 cm thick probably extends 2 km southward beneath bottom sediments and fringing microbial mats of the main salt pond studied (Bumber Well Pond). The horizon contains a basal northern unit of pink bioclastic sand that probably relates to the cutting of scours or to enlargement of pre- existing scours in the beach ridges to the north. The horizon also contains a widespread unit of marine molluscan shells that extends as float onto the limestone platform. SALT PONDS. The sand and shell horizon marks an event that changed the island's interior water bodies from nearly marine to hypersaline. The nearly marine conditions are recorded by mollusk-rich lagoonal mud below the event horizon, while the hypersaline conditions are marked mollusk-free salt-pond deposits above. The salinity change probably resulted from choking of the lagoon's likely inlet (or inlets) on Anegada's south side. A tsunami from the north, after scouring beach ridges and moving cobbles and boulders, probably also built sandy fans into the former inlet(s). This inferred tsunami probably postdates 1460-1620 C.E., the two-sigma range corresponding to the youngest radiocarbon age obtained on individual detrital shells in the event horizon. Potential correlates, in addition to earthquakes along the Puerto Rico Trench, include the transatlantic tsunami associated with the 1755 Lisbon earthquake. This work is part of Nuclear Regulatory Commission project N6480, a tsunam-hazard assessment for the eastern United States. We especially thank, in addition, Cindy Rolli of BVI Disaster Management and field assistant Caitlin Herlihy.

Investigating the change of causality in emerging property markets during the financial tsunami

NASA Astrophysics Data System (ADS)

Hui, Eddie C. M.; Chen, Jia

2012-08-01

In this paper, we employ the multivariate CUSUM (cumulative sum) test for covariance structure as well as the renormalized partial directed coherence (PDC) method to capture the structural causality change of real estate stock indices of five emerging Asian countries and regions (i.e., Thailand, Malaysia, South Korea, PR China, and Taiwan). Meanwhile, we develop a method to make the comparison of renormalized PDC more intuitive and a set of criteria to measure the result. One of our findings indicates that the regional influence of the Chinese real estate stock market on the causality structure of the five markets has arisen under the effect of the financial tsunami.

Micromechanisms with floating pivot

DOEpatents

Garcia, Ernest J.

2001-03-06

A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.

A consistent model for tsunami actions on buildings

NASA Astrophysics Data System (ADS)

Foster, A.; Rossetto, T.; Eames, I.; Chandler, I.; Allsop, W.

2016-12-01

The Japan (2011) and Indian Ocean (2004) tsunami resulted in significant loss of life, buildings, and critical infrastructure. The tsunami forces imposed upon structures in coastal regions are initially due to wave slamming, after which the quasi-steady flow of the sea water around buildings becomes important. An essential requirement in both design and loss assessment is a consistent model that can accurately predict these forces. A model suitable for predicting forces in the in the quasi-steady range has been established as part of a systematic programme of research by the UCL EPICentre to understand the fundamental physical processes of tsunami actions on buildings, and more generally their social and economic consequences. Using the pioneering tsunami generator at HR Wallingford, this study considers the influence of unsteady flow conditions on the forces acting upon a rectangular building occupying 10-80% of a channel for 20-240 second wave periods. A mathematical model based upon basic open-channel flow principles is proposed, which provides empirical estimates for drag and hydrostatic coefficients. A simple force prediction equation, requiring only basic flow velocity and wave height inputs is then developed, providing good agreement with the experimental results. The results of this study demonstrate that the unsteady forces from the very long waves encountered during tsunami events can be predicted with a level of accuracy and simplicity suitable for design and risk assessment.

A possible transoceanic tsunami directed toward the U.S. west coast from the Semidi segment, Alaska convergent margin

USGS Publications Warehouse

von Huene, Roland E.; Miller, John J.; Dartnell, Peter

2016-01-01

The Semidi segment of the Alaska convergent margin appears capable of generating a giant tsunami like the one produced along the nearby Unimak segment in 1946. Reprocessed legacy seismic reflection data and a compilation of multibeam bathymetric surveys reveal structures that could generate such a tsunami. A 200 km long ridge or escarpment with crests >1 km high is the surface expression of an active out-of-sequence fault zone, recently referred to as a splay fault. Such faults are potentially tsunamigenic. This type of fault zone separates the relatively rigid rock of the margin framework from the anelastic accreted sediment prism. Seafloor relief of the ridge exceeds that of similar age accretionary prism ridges indicating preferential slip along the splay fault zone. The greater slip may derive from Quaternary subduction of the Patton Murray hot spot ridge that extends 200 km toward the east across the north Pacific. Estimates of tsunami repeat times from paleotsunami studies indicate that the Semidi segment could be near the end of its current inter-seismic cycle. GPS records from Chirikof Island at the shelf edge indicate 90% locking of plate interface faults. An earthquake in the shallow Semidi subduction zone could generate a tsunami that will inundate the US west coast more than the 1946 and 1964 earthquakes because the Semidi continental slope azimuth directs a tsunami southeastward.

Community variations in population exposure to near-field tsunami hazards as a function of pedestrian travel time to safety

USGS Publications Warehouse

Wood, Nathan J.; Schmidtlein, Mathew C.

2013-01-01

Efforts to characterize population exposure to near-field tsunami threats typically focus on quantifying the number and type of people in tsunami-hazard zones. To develop and prioritize effective risk-reduction strategies, emergency managers also need information on the potential for successful evacuations and how this evacuation potential varies among communities. To improve efforts to properly characterize and differentiate near-field tsunami threats among multiple communities, we assess community variations in population exposure to tsunamis as a function of pedestrian travel time to safety. We focus our efforts on the multiple coastal communities in Grays Harbor and Pacific Counties (State of Washington, USA), where a substantial resident and visitor population is threatened by near-field tsunamis related to a potential Cascadia subduction zone earthquake. Anisotropic, path-distance modeling is conducted to estimate travel times to safety and results are merged with various population data, including residents, employees, public venues, and dependent-care facilities. Results suggest that there is substantial variability among communities in the number of people that may have insufficient time to evacuate. Successful evacuations may be possible in some communities assuming slow-walking speeds, are plausible in others if travel speeds are increased, and are unlikely in another set of communities given the large distances and short time horizon. Emergency managers can use these results to prioritize the location and determine the most appropriate type of tsunami risk-reduction strategies, such as education and training in areas where evacuations are plausible and vertical-evacuation structures in areas where they are not.

Currents, drag, and sediment transport induced by a tsunami

USGS Publications Warehouse

Lacy, Jessica R.; Rubin, David M.; Buscombe, Daniel

2012-01-01

We report observations of water surface elevation, currents, and suspended sediment concentration (SSC) from a 10-m deep site on the inner shelf in northern Monterey Bay during the arrival of the 2010 Chile tsunami. Velocity profiles were measured from 3.5 m above the bed (mab) to the surface at 2 min intervals, and from 0.1 to 0.7 mab at 1 Hz. SSC was determined from the acoustic backscatter of the near-bed profiler. The initial tsunami waves were directed cross shore and had a period of approximately 16 min. Maximum wave height was 1.1 m, and maximum current speed was 0.36 m/s. During the strongest onrush, near-bed velocities were clearly influenced by friction and a logarithmic boundary layer developed, extending more than 0.3 mab. We estimated friction velocity and bed shear stress from the logarithmic profiles. The logarithmic structure indicates that the flow can be characterized as quasi-steady at these times. At other phases of the tsunami waves, the magnitude of the acceleration term was significant in the near-bed momentum equation, indicating unsteady flow. The maximum tsunami-induced bed shear stress (0.4 N/m2) exceeded the critical shear stress for the medium-grained sand on the seafloor. Cross-shore sediment flux was enhanced by the tsunami. Oscillations of water surface elevation and currents continued for several days. The oscillations were dominated by resonant frequencies, the most energetic of which was the fundamental longitudinal frequency of Monterey Bay. The maximum current speed (hourly-timescale) in 18 months of observations occurred four hours after the tsunami arrived.

Tsunami Loss Assessment For Istanbul

NASA Astrophysics Data System (ADS)

Hancilar, Ufuk; Cakti, Eser; Zulfikar, Can; Demircioglu, Mine; Erdik, Mustafa

2010-05-01

Tsunami risk and loss assessment incorporating with the inundation mapping in Istanbul and the Marmara Sea region are presented in this study. The city of Istanbul is under the threat of earthquakes expected to originate from the Main Marmara branch of North Anatolian Fault System. In the Marmara region the earthquake hazard reached very high levels with 2% annual probability of occurrence of a magnitude 7+ earthquake on the Main Marmara Fault. Istanbul is the biggest city of Marmara region as well as of Turkey with its almost 12 million inhabitants. It is home to 40% of the industrial facilities in Turkey and operates as the financial and trade hub of the country. Past earthquakes have evidenced that the structural reliability of residential and industrial buildings, as well as that of lifelines including port and harbor structures in the country is questionable. These facts make the management of earthquake risks imperative for the reduction of physical and socio-economic losses. The level of expected tsunami hazard in Istanbul is low as compared to earthquake hazard. Yet the assets at risk along the shores of the city make a thorough assessment of tsunami risk imperative. Important residential and industrial centres exist along the shores of the Marmara Sea. Particularly along the northern and eastern shores we see an uninterrupted settlement pattern with industries, businesses, commercial centres and ports and harbours in between. Following the inundation maps resulting from deterministic and probabilistic tsunami hazard analyses, vulnerability and risk analyses are presented and the socio-economic losses are estimated. This study is part of EU-supported FP6 project ‘TRANSFER'.

TIDE TOOL: Open-Source Sea-Level Monitoring Software for Tsunami Warning Systems

NASA Astrophysics Data System (ADS)

Weinstein, S. A.; Kong, L. S.; Becker, N. C.; Wang, D.

2012-12-01

A tsunami warning center (TWC) typically decides to issue a tsunami warning bulletin when initial estimates of earthquake source parameters suggest it may be capable of generating a tsunami. A TWC, however, relies on sea-level data to provide prima facie evidence for the existence or non-existence of destructive tsunami waves and to constrain tsunami wave height forecast models. In the aftermath of the 2004 Sumatra disaster, the International Tsunami Information Center asked the Pacific Tsunami Warning Center (PTWC) to develop a platform-independent, easy-to-use software package to give nascent TWCs the ability to process WMO Global Telecommunications System (GTS) sea-level messages and to analyze the resulting sea-level curves (marigrams). In response PTWC developed TIDE TOOL that has since steadily grown in sophistication to become PTWC's operational sea-level processing system. TIDE TOOL has two main parts: a decoder that reads GTS sea-level message logs, and a graphical user interface (GUI) written in the open-source platform-independent graphical toolkit scripting language Tcl/Tk. This GUI consists of dynamic map-based clients that allow the user to select and analyze a single station or groups of stations by displaying their marigams in strip-chart or screen-tiled forms. TIDE TOOL also includes detail maps of each station to show each station's geographical context and reverse tsunami travel time contours to each station. TIDE TOOL can also be coupled to the GEOWARE™ TTT program to plot tsunami travel times and to indicate the expected tsunami arrival time on the marigrams. Because sea-level messages are structured in a rich variety of formats TIDE TOOL includes a metadata file, COMP_META, that contains all of the information needed by TIDE TOOL to decode sea-level data as well as basic information such as the geographical coordinates of each station. TIDE TOOL can therefore continuously decode theses sea-level messages in real-time and display the time-series data in the GUI as well. This GUI also includes mouse-clickable functions such as zooming or expanding the time-series display, measuring tsunami signal characteristics (arrival time, wave period and amplitude, etc.), and removing the tide signal from the time-series data. De-tiding of the time series is necessary to obtain accurate measurements of tsunami wave parameters and to maintain accurate historical tsunami databases. With TIDE TOOL, de-tiding is accomplished with a set of tide harmonic coefficients routinely computed and updated at PTWC for many of the stations in PTWC's inventory (~570). PTWC also uses the decoded time series files (previous 3-5 days' worth) to compute on-the-fly tide coefficients. The latter is useful in cases where the station is new and a long-term stable set of tide coefficients are not available or cannot be easily obtained due to various non-astronomical effects. The international tsunami warning system is coordinated globally by the UNESCO IOC, and a number of countries in the Pacific and Indian Ocean, and Caribbean depend on Tide Tool to monitor tsunamis in real time.

The role of deposits in tsunami risk assessment

USGS Publications Warehouse

Jaffe, B.

2008-01-01

An incomplete catalogue of tsunamis in the written record hinders tsunami risk assessment. Tsunami deposits, hard evidence of tsunami, can be used to extend the written record. The two primary factors in tsunami risk, tsunami frequency and magnitude, can be addressed through field and modeling studies of tsunami deposits. Recent research has increased the utility of tsunami deposits in tsunami risk assessment by improving the ability to identify tsunami deposits and developing models to determine tsunami magnitude from deposit characteristics. Copyright ASCE 2008.

Improved tsunami impact assessments: validation, comparison and the integration of hydrodynamic modeling

NASA Astrophysics Data System (ADS)

Tarbotton, C.; Walters, R. A.; Goff, J. R.; Dominey-Howes, D.; Turner, I. L.

2012-12-01

As communities become increasingly aware of the risks posed by tsunamis, it is important to develop methods for predicting the damage they can cause to the built environment. This will provide the information needed to make informed decisions regarding land-use, building codes, and evacuation. At present, a number of tsunami-building vulnerability assessment models are available, however, the relative infrequency and destructive nature of tsunamis has long made it difficult to obtain the data necessary to adequately validate and compare them. Further complicating matters is that the inundation of a tsunami in the built environment is very difficult model, as is the response of a building to the hydraulic forces that a tsunami generates. Variations in building design and condition will significantly affect a building's susceptibility to damage. Likewise, factors affecting the flow conditions at a building (i.e. surrounding structures and topography), will greatly affect its exposure. This presents significant challenges for practitioners, as they are often left in the dark on how to use hazard modeling and vulnerability assessment techniques together to conduct the community-scale impact studies required for tsunami planning. This paper presents the results of an in-depth case study of Yuriage, Miyagi Prefecture - a coastal city in Japan that was badly damaged by the 2011 Tohoku tsunami. The aim of the study was twofold: 1) To test and compare existing tsunami vulnerability assessment models and 2) To more effectively utilize hydrodynamic models in the context of tsunami impact studies. Following the 2011 Tohoku event, an unprecedented quantity of field data, imagery and video emerged. Yuriage in particular, features a comprehensive set of street level Google Street View imagery, available both before and after the event. This has enabled the collection of a large dataset describing the characteristics of the buildings existing before the event as well the subsequent damage that they sustained during. These data together with the detailed results from hydrodynamic models have been used to provide the building, damage and hazard data necessary to rigorously test and compare existing vulnerability assessments techniques. The result is a much-improved understanding of the capabilities of existing vulnerability assessment techniques, as well as important improvements to their assessment framework This provides much needed guidance to practitioners on how to conduct tsunami impact assessments in the future. Furthermore, the study introduces some new methods of integrating hydrodynamic models into vulnerability assessment models, offering guidance on how to more effectively model tsunami inundation in the built environment.

The role of integrating natural and social science concepts for risk governance and the design of people-centred early warning systems. Case study from the German-Indonesian Tsunami Early Warning System Project (GITEWS)

NASA Astrophysics Data System (ADS)

Gebert, Niklas; Post, Joachim

2010-05-01

The development of early warning systems are one of the key domains of adaptation to global environmental change and contribute very much to the development of societal reaction and adaptive capacities to deal with extreme events. Especially, Indonesia is highly exposed to tsunami. In average every three years small and medium size tsunamis occur in the region causing damage and death. In the aftermath of the Indian Ocean Tsunami 2004, the German and Indonesian government agreed on a joint cooperation to develop a People Centered End-to-End Early Warning System (GITEWS). The analysis of risk and vulnerability, as an important step in risk (and early warning) governance, is a precondition for the design of effective early warning structures by delivering the knowledge base for developing institutionalized quick response mechanisms of organizations involved in the issuing of a tsunami warning, and of populations exposed to react to warnings and to manage evacuation before the first tsunami wave hits. Thus, a special challenge for developing countries is the governance of complex cross-sectoral and cross-scale institutional, social and spatial processes and requirements for the conceptualization, implementation and optimization of a people centered tsunami early warning system. In support of this, the risk and vulnerability assessment of the case study aims at identifying those factors that constitute the causal structure of the (dis)functionality between the technological warning and the social response system causing loss of life during an emergency situation: Which social groups are likely to be less able to receive and respond to an early warning alert? And, are people able to evacuate in due time? Here, only an interdisciplinary research approach is capable to analyze the socio-spatial and environmental conditions of vulnerability and risk and to produce valuable results for decision makers and civil society to manage tsunami risk in the early warning context. This requires the integration of natural / spatial and social science concepts, methods and data: E.g. a scenario based approach for tsunami inundation modeling was developed to provide decision makers with options to decide up to what level they aim to protect their people and territory, on the contrary household surveys were conducted for the spatial analysis of the evacuation preparedness of the population as a function of place specific hazard, risk, warning and evacuation perception; remote sensing was applied for the spatial analysis (land-use) of the socio-physical conditions of a city and region for evacuation; and existing social / population statistics were combined with land-use data for the precise spatial mapping of the population exposed to tsunami risks. Only by utilizing such a comprehensive assessment approach valuable information for risk governance can be generated. The results are mapped using GIS and designed according to the specific needs of different end-users, such as public authorities involved in the design of warning dissemination strategies, land-use planners (shelter planning, road network configuration) and NGOs mandated to provide education for the general public on tsunami risk and evacuation behavior. The case study of the city of Padang (one of the pilot areas of GITEWS), Indonesia clearly show, that only by intersecting social (vulnerability) and natural hazards research a comprehensive picture on tsunami risk can be provided with which risk governance in the early warning context can be conducted in a comprehensive, systemic and sustainable manner.

The September 16, 2015 Illapel Tsunami - Sedimentology of tsunami deposits at the beaches of La Serena and Coquimbo

NASA Astrophysics Data System (ADS)

Bahlburg, Heinrich; Nentwig, Vanessa; Matthias, Kreutzer

2016-04-01

On September 16, 2015, at 7:54 pm local time, an earthquake with Mw 8.3 occurred off the coast of Central Chile, 46 km west of the town of Illapel. Its hypocenter was located at a depth of 8.7 km in the transition zone from the Chilean flat slab to the central Chilean steep slab subduction geometry, and near the intersection of the Juan Fernandez Ridge with the South America plate. The quake caused a predominantly minor tsunami between Caldera (c. 27°S) and Los Vilos (c. 32°S). Only at Coquimbo and La Serena (c. 30°S) did the tsunami attain large wave heights on the order of 4.5 m leading to flooding and destruction of infrastructure. Maximum inundation distance was c. 700 m at Playa Changa, Coquimbo Bay. Minor flooding occurred along the northward adjacent beaches of La Serena reaching inundation distances of up to 150 m. Tsunami deposits are usually the only observable evidence of past events. To understand how tsunami deposits form and are preserved, and how they can be identified in the geological record, it is of paramount importance to undertake detailed studies in the wake of actual events. Here we report initial field data of a sedimentological post-tsunami field survey undertaken in October 2015. The most comprehensive and instructive sedimentological record of the September 16, 2015 tsunami is preserved at Playa Los Fuertes in La Serena. Along a 30 m long trench perpendicular to the coast we observed a laminated package of tsunami deposits of varying thickness. The deposits have an erosive basal unconformity with an amplitude of at least 10 cm. The preserved deposit thickness varies between 10 an 50 cm. The deposit consists of 7 layers of variable thickness, ranging between dark laminae a few millimeters thick and rich in heavy minerals, and lighter colored sand layers up to 15 cm thick. Grain size distributions are moderately well to well sorted and unimodal with modes between 1.3 and 2.0 Φ (medium sand). A c. 10 cm thick laminated layer in the central part of the vertical section includes mildly trough-shaped crossbeds indicating landward flow, a c. 5 cm thick layer 10 cm below the top in the interior part of the trench contains planar cross beds formed by outflow currents. Water escape occur as small sand diapirs and volcanoes within the final deposit. Water escape through small volcanoes appears to have been coeval to formation of the overlying layer by traction deposition as sand issuing from the lower layer has been preserved as a thin plume deformed in the downcurrent, i.e. landward, direction in the newly forming upper layer. Other sectors of the sediment show sand diapirs intruding up to 15 cm into the overlying tsunami deposit. The assemblage of laminae, layers and sedimentary structures indicates that the deposit records at least two events of tsunami inflow indicated by crossbeds and deformed sand volcano plumes, and one outflow event. Intervening layers without directional structures can not be assigned unequivocally to either inflow or outflow deposition.

Defining Tsunami Magnitude as Measure of Potential Impact

NASA Astrophysics Data System (ADS)

Titov, V. V.; Tang, L.

2016-12-01

The goal of tsunami forecast, as a system for predicting potential impact of a tsunami at coastlines, requires quick estimate of a tsunami magnitude. This goal has been recognized since the beginning of tsunami research. The work of Kajiura, Soloviev, Abe, Murty, and many others discussed several scales for tsunami magnitude based on estimates of tsunami energy. However, difficulties of estimating tsunami energy based on available tsunami measurements at coastal sea-level stations has carried significant uncertainties and has been virtually impossible in real time, before tsunami impacts coastlines. The slow process of tsunami magnitude estimates, including collection of vast amount of available coastal sea-level data from affected coastlines, made it impractical to use any tsunami magnitude scales in tsunami warning operations. Uncertainties of estimates made tsunami magnitudes difficult to use as universal scale for tsunami analysis. Historically, the earthquake magnitude has been used as a proxy of tsunami impact estimates, since real-time seismic data is available of real-time processing and ample amount of seismic data is available for an elaborate post event analysis. This measure of tsunami impact carries significant uncertainties in quantitative tsunami impact estimates, since the relation between the earthquake and generated tsunami energy varies from case to case. In this work, we argue that current tsunami measurement capabilities and real-time modeling tools allow for establishing robust tsunami magnitude that will be useful for tsunami warning as a quick estimate for tsunami impact and for post-event analysis as a universal scale for tsunamis inter-comparison. We present a method for estimating the tsunami magnitude based on tsunami energy and present application of the magnitude analysis for several historical events for inter-comparison with existing methods.

Great East Japan Earthquake Tsunami

NASA Astrophysics Data System (ADS)

Iijima, Y.; Minoura, K.; Hirano, S.; Yamada, T.

2011-12-01

The 11 March 2011, Mw 9.0 Great East Japan Earthquake, already among the most destructive earthquakes in modern history, emanated from a fault rupture that extended an estimated 500 km along the Pacific coast of Honshu. This earthquake is the fourth among five of the strongest temblors since AD 1900 and the largest in Japan since modern instrumental recordings began 130 years ago. The earthquake triggered a huge tsunami, which invaded the seaside areas of the Pacific coast of East Japan, causing devastating damages on the coast. Artificial structures were destroyed and planted forests were thoroughly eroded. Inrush of turbulent flows washed backshore areas and dunes. Coastal materials including beach sand were transported onto inland areas by going-up currents. Just after the occurrence of the tsunami, we started field investigation of measuring thickness and distribution of sediment layers by the tsunami and the inundation depth of water in Sendai plain. Ripple marks showing direction of sediment transport were the important object of observation. We used a soil auger for collecting sediments in the field, and sediment samples were submitted for analyzing grain size and interstitial water chemistry. Satellite images and aerial photographs are very useful for estimating the hydrogeological effects of tsunami inundation. We checked the correspondence of micro-topography, vegetation and sediment covering between before and after the tsunami. The most conspicuous phenomenon is the damage of pine forests planted in the purpose of preventing sand shifting. About ninety-five percent of vegetation coverage was lost during the period of rapid currents changed from first wave. The landward slopes of seawalls were mostly damaged and destroyed. Some aerial photographs leave detailed records of wave destruction just behind seawalls, which shows the occurrence of supercritical flows. The large-scale erosion of backshore behind seawalls is interpreted to have been caused by supercritical flows, resulting in the loss of landward seawall slopes. Such erosion was also observed at landward side of footpath between rice fields. The Sendai plain was subjected just after the main shock of the earthquake. Seawater inundation resulting from tsunami run-up lasted two months. The historical document Sandai-jitsuroku, which gives a detailed history of all of Japan, describes the Jogan earthquake and subsequent tsunami which have attacked Sendai plain in AD 869. The document describes the prolonged period of flooding, and it is suggested that co-seismic subsidence of the plain took place. The inundation area of the Jogan tsunami estimated by the distribution of tsunami deposit mostly overlaps with that of the 3.11 tsunami. Considering the very similarity of seismic shocks between the both, we interpreted the Great East Japan Earthquake Tsunami is the second coming of the Jogan Earthquake Tsunami.

Dynamic response mitigation of floating wind turbine platforms using tuned liquid column dampers.

PubMed

Jaksic, V; Wright, C S; Murphy, J; Afeef, C; Ali, S F; Mandic, D P; Pakrashi, V

2015-02-28

In this paper, we experimentally study and compare the effects of three combinations of multiple tuned liquid column dampers (MTLCDs) on the dynamic performance of a model floating tension-leg platform (TLP) structure in a wave basin. The structural stability and safety of the floating structure during operation and maintenance is of concern for the performance of a renewable energy device that it might be supporting. The dynamic responses of the structure should thus be limited for these renewable energy devices to perform as intended. This issue is particularly important during the operation of a TLP in extreme weather conditions. Tuned liquid column dampers (TLCDs) can use the power of sloshing water to reduce surge motions of a floating TLP exposed to wind and waves. This paper demonstrates the potential of MTLCDs in reducing dynamic responses of a scaled TLP model through an experimental study. The potential of using output-only statistical markers for monitoring changes in structural conditions is also investigated through the application of a delay vector variance (DVV) marker for different conditions of control for the experiments. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Pedestrian Evacuation Analysis for Tsunami Hazards

NASA Astrophysics Data System (ADS)

Jones, J. M.; Ng, P.; Wood, N. J.

2014-12-01

Recent catastrophic tsunamis in the last decade, as well as the 50th anniversary of the 1964 Alaskan event, have heightened awareness of the threats these natural hazards present to large and increasing coastal populations. For communities located close to the earthquake epicenter that generated the tsunami, strong shaking may also cause significant infrastructure damage, impacting the road network and hampering evacuation. There may also be insufficient time between the earthquake and first wave arrival to rely on a coordinated evacuation, leaving at-risk populations to self-evacuate on foot and across the landscape. Emergency managers evaluating these coastal risks need tools to assess the evacuation potential of low-lying areas in order to discuss mitigation options, which may include vertical evacuation structures to provide local safe havens in vulnerable communities. The U.S. Geological Survey has developed the Pedestrian Evacuation Analyst software tool for use by researchers and emergency managers to assist in the assessment of a community's evacuation potential by modeling travel times across the landscape and producing both maps of travel times and charts of population counts with corresponding times. The tool uses an anisotropic (directionally dependent) least cost distance model to estimate evacuation potential and allows for the variation of travel speed to measure its effect on travel time. The effectiveness of vertical evacuation structures on evacuation time can also be evaluated and compared with metrics such as travel time maps showing each structure in place and graphs displaying the percentage change in population exposure for each structure against the baseline. Using the tool, travel time maps and at-risk population counts have been generated for some coastal communities of the U.S. Pacific Northwest and Alaska. The tool can also be used to provide valuable decision support for tsunami vertical evacuation siting.

Damage identification of a TLP floating wind turbine by meta-heuristic algorithms

NASA Astrophysics Data System (ADS)

Ettefagh, M. M.

2015-12-01

Damage identification of the offshore floating wind turbine by vibration/dynamic signals is one of the important and new research fields in the Structural Health Monitoring (SHM). In this paper a new damage identification method is proposed based on meta-heuristic algorithms using the dynamic response of the TLP (Tension-Leg Platform) floating wind turbine structure. The Genetic Algorithms (GA), Artificial Immune System (AIS), Particle Swarm Optimization (PSO), and Artificial Bee Colony (ABC) are chosen for minimizing the object function, defined properly for damage identification purpose. In addition to studying the capability of mentioned algorithms in correctly identifying the damage, the effect of the response type on the results of identification is studied. Also, the results of proposed damage identification are investigated with considering possible uncertainties of the structure. Finally, for evaluating the proposed method in real condition, a 1/100 scaled experimental setup of TLP Floating Wind Turbine (TLPFWT) is provided in a laboratory scale and the proposed damage identification method is applied to the scaled turbine.

Satellite-based observations of tsunami-induced mesosphere airglow perturbations

NASA Astrophysics Data System (ADS)

Yang, Yu-Ming; Verkhoglyadova, Olga; Mlynczak, Martin G.; Mannucci, Anthony J.; Meng, Xing; Langley, Richard B.; Hunt, Linda A.

2017-01-01

Tsunami-induced airglow emission perturbations were retrieved by using space-based measurements made by the Sounding of the Atmosphere using Broad-band Emission Radiometry (SABER) instrument on board the Thermosphere-Ionosphere-Mesosphere Energetics Dynamics spacecraft. At and after the time of the Tohoku-Oki earthquake on 11 March 2011, and the Chile earthquake on 16 September 2015, the spacecraft was performing scans over the Pacific Ocean. Significant ( 10% relative to the ambient emission profiles) and coherent nighttime airglow perturbations were observed in the mesosphere following Sounding of the Atmosphere using Broad-band Emission Radiometry limb scans intercepting tsunami-induced atmospheric gravity waves. Simulations of emission variations are consistent with the physical characteristics of the disturbances at the locations of the corresponding SABER scans. Airglow observations and model simulations suggest that atmospheric neutral density and temperature perturbations can lead to the observed amplitude variations and multipeak structures in the emission profiles. This is the first time that airglow emission rate perturbations associated with tsunamis have been detected with space-based measurements.

New method to determine initial surface water displacement at tsunami source

NASA Astrophysics Data System (ADS)

Lavrentyev, Mikhail; Romanenko, Alexey; Tatarintsev, Pavel

2013-04-01

Friday, March 11, 2011 at 05:46:23 UTC, Japan was struck by an 8.9-magnitude earthquake near its Northeastern coast. This is one of the largest earthquakes that Japan has ever experienced. Tsunami waves swept away houses and cars and caused massive human losses. To predict tsunami wave parameters better and faster, we propose to improve data inversion scheme and achieve the performance gain of data processing. One of the reasons of inaccurate predictions of tsunami parameters is that very little information is available about the initial disturbance of the sea bed at tsunami source. In this paper, we suggest a new way of improving the quality of tsunami source parameters prediction. Modern computational technologies can accurately calculate tsunami wave propagation over the deep ocean provided that the initial displacement (perturbation of the sea bed at tsunami source) is known [4]. Direct geophysical measurements provide the location of an earthquake hypocenter and its magnitude (the released energy evaluation). Among the methods of determination of initial displacement the following ones should be considered. Calculation through the known fault structure and available seismic information. This method is widely used and provides useful information. However, even if the exact knowledge about rock blocks shifts is given, recalculation in terms of sea bed displacement is needed. This results in a certain number of errors. GPS data analysis. This method was developed after the December 2004 event in the Indian Ocean. A good correlation between dry land based GPS sensors and tsunami wave parameters was observed in the particular case of the West coast of Sumatra, Indonesia. This approach is very unique and can hardly been used in other geo locations. Satellite image analysis. The resolution of modern satellite images has dramatically improved. In the future, correct data of sea surface displacement will probably be available in real time, right after a tsunamigenic earthquake. However, today it is not yet possible. Ground-based sea radars. This is an effective tool for direct measurement of tsunami wave. At the same time, the wave is measured at a rather narrow area in front of the radar and does not include information about neighboring parts of the wave. Direct measurement of tsunami wave at deep water [2]. Today, this technology is certainly among the most useful and promising. The DART II® system consists of a seafloor bottom pressure recording (BPR) system, capable of detecting tsunamis as small as 1 cm, and a moored surface buoy for real-time communications. We focus our research on improving the later method, direct measurement of tsunami wave at deep water. We suggest the new way to analyze DART data, modifying the methodology originally proposed by V. Titov. Smaller system of unit sources [3] should be considered to approximate all typical shapes of initial disturbance by several suitable basis functions. To successfully implement it, performance of data analysis should be dramatically improved. This could be done by using a signal orthogonalization procedure for considered system of unit sources and calculation of Fourier coefficients of the measured time series with respect to orthogonal basis. The approach suggested was used as a part of computerized workstation for tsunami hazard monitoring [5-6]. National Oceanic and Atmospheric Administration Center for Tsunami Research. URL: http://nctr.pmel.noaa.gov/honshu20110311/ National Data Buoy Center. URL: http://www.ndbc.noaa.gov/dart.shtml National Oceanic and Atmospheric Administration Center for Tsunami Research. URL: http://sift.pmel.noaa.gov/thredds/dodsC/uncompressed/ National Oceanic and Atmospheric Administration Center for Tsunami Research. URL: http://nctr.pmel.noaa.gov/model.html Alexey Romanenko, Mikhail Lavrentiev-jr, Vasily Titov, "Modern Architecture for Tsunami Hazard Mitigation" // Asia Oceania Geosciences Society (AOGS-2012), ISBN 978-981-07-2049-0 Mikhail Lavrentiev-jr, Andrey Marchuk, Alexey Romanenko, Konstantin Simonov, and Vasiliy Titov, "Computerized Workstation for Tsunami Hazard Monitoring", Geophysical research abstracts, Vol. 12, EGU2010-3021-1, 2010

Project TANDEM (Tsunamis in the Atlantic and the English ChaNnel: Definition of the Effects through numerical Modeling) (2014-2018): a French initiative to draw lessons from the Tohoku-oki tsunami on French coastal nuclear facilities

NASA Astrophysics Data System (ADS)

Hébert, Hélène; Abadie, Stéphane; Benoit, Michel; Créach, Ronan; Frère, Antoine; Gailler, Audrey; Garzaglia, Sébastien; Hayashi, Yutaka; Loevenbruck, Anne; Macary, Olivier; Marcer, Richard; Morichon, Denis; Pedreros, Rodrigo; Rebour, Vincent; Ricchiuto, Mario; Silva Jacinto, Ricardo; Terrier, Monique; Toucanne, Samuel; Traversa, Paola; Violeau, Damien

2014-05-01

TANDEM (Tsunamis in the Atlantic and the English ChaNnel: Definition of the Effects through numerical Modeling) is a French research project dedicated to the appraisal of coastal effects due to tsunami waves on the French coastlines, with a special focus on the Atlantic and Channel coastlines, where French civil nuclear facilities have been operating since about 30 years. This project aims at drawing conclusions from the 2011 catastrophic tsunami, and will allow, together with a Japanese research partner, to design, adapt and validate numerical methods of tsunami hazard assessment, using the outstanding database of the 2011 tsunami. Then the validated methods will be applied to estimate, as accurately as possible, the tsunami hazard for the French Atlantic and Channel coastlines, in order to provide guidance for risk assessment on the nuclear facilities. The project TANDEM follows the recommendations of International Atomic Energy Agency (IAEA) to analyse the tsunami exposure of the nuclear facilities, as well as the recommendations of the French Nuclear Safety Authority (Autorité de Sûreté Nucléaire, ASN) in the aftermath of the 2011 catastrophe, which required the licensee of nuclear facilities to conduct complementary safety assessments (CSA), also including "the robustness beyond their design basis". The tsunami hazard deserves an appraisal in the light of the 2011 catastrophe, to check whether any unforeseen tsunami impact can be expected for these facilities. TANDEM aims at defining the tsunami effects expected for the French Atlantic and Channel coastlines, basically from numerical modeling methods, through adaptation and improvement of numerical methods, in order to study tsunami impacts down to the interaction with coastal structures (thus sometimes using 3D approaches) (WP1). Then the methods will be tested to better characterize and quantify the associated uncertainties (in the source, the propagation, and the coastal impact) (WP2). The project will benefit from a Japanese cooperation (Meteorological Research Institute, MRI) to study in detail the coastal impact of the 2011 Tohoku tsunami (WP3). In this framework TANDEM will apply the models to the French study area, which includes investigating historical documents, defining the possible tsunamigenic sources able to strike the regions of interest (earthquakes and/or landslides), and modeling the coastal effects at a regional scale and for selected sites. Using high resolution bathymetric and topographic data in the frame of Litto3D (a French project whose main objective is to build a seamless integrated topographic and bathymetric coastal Digital Terrain Model), TANDEM will thoroughly investigate possible sources, through a detailed characterization of the slope stability off the coastlines (for the Celtic and Armorican margins, Bay of Biscay), and estimate the coastal impacts. It will also consider events (Canaries) whose assumed catastrophic impact has been widely discussed these recent years, needing a reappraisal regarding French coastlines. A special attention will also be paid to the estimation of the return periods expected for the tsunami scenarios.

Tsunamis as geomorphic crises: Lessons from the December 26, 2004 tsunami in Lhok Nga, West Banda Aceh (Sumatra, Indonesia)

NASA Astrophysics Data System (ADS)

Paris, Raphaël; Wassmer, Patrick; Sartohadi, Junun; Lavigne, Franck; Barthomeuf, Benjamin; Desgages, Emilie; Grancher, Delphine; Baumert, Philippe; Vautier, Franck; Brunstein, Daniel; Gomez, Christopher

2009-03-01

Large tsunamis are major geomorphic crises, since they imply extensive erosion, sediment transport and deposition in a few minutes and over hundreds of kilometres of coast. Nevertheless, little is known about their geomorphologic imprints. The December 26, 2004 tsunami in Sumatra (Indonesia) was one of the largest and deadliest tsunamis in recorded human history. We present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the Lhok Nga Bay, located to the West of Banda Aceh (northwest Sumatra). The geomorphological impact of the tsunami is evidenced by: beach erosion (some beaches have almost disappeared); destruction of sand barriers protecting the lagoons or at river mouths; numerous erosion escarpments typically in the order of 0.5-1.5 m when capped by soil and more than 2 m in dunes; bank erosion in the river beds (the retreat along the main river is in the order of 5-15 m, with local retreats exceeding 30 m); large scars typically 20-50 cm deep on slopes; dislodgement of blocks along fractures and structural ramps on cliffs. The upper limit of erosion appears as a continuous trimline at 20-30 m a.s.l., locally reaching 50 m. The erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds. The overall coastal retreat from Lampuuk to Leupung was 60 m (550,000 m 2) and locally exceeded 150 m. Over 276,000 m 3 of coastal sediments were eroded by the tsunami along the 9.2 km of sandy coast. The mean erosion rate of the beaches was ~ 30 m 3/m of coast and locally exceeded 80 m 3/m. The most eroded coasts were tangent to the tsunami wave train, which was coming from the southwest. The fringing reefs were not efficient in reducing the erosional impact of the tsunami. The 220 boulders measured range from 0.3 to 7.2 m large (typically 0.7-1.5 m), with weights from over 50 kg up to 85 t. We found one boulder, less than 1 m large, at 1 km from the coastline, but all the others were transported less than 450 m (< 7 m a.s.l.). No fining landward boulder size distribution could be detected. The coincidence of different size modes, from boulders to fine sands, with independent spatial distributions, suggests that all the material was not transported in suspension, but rather by a combination of suspension and bed load transport. Finally, the spatial and size distributions of tsunami boulder deposits mostly depend on the location and characteristics of their source (coral reef, beach rock, platform, dams), together with clast and surface interference during transport. One year after, the coastal environment in northwest Sumatra is still in a post-tsunami dynamic. Thus, the difference between the largest tsunamis (height > 30 m) and the moderate tsunamis (height < 10 m) could be their long-term impact on coastal environments.

Tsunami on Sanriku Coast in 1586: Orphan or Ghost Tsunami ?

NASA Astrophysics Data System (ADS)

Satake, K.

2017-12-01

The Peruvian earthquake on July 9, 1586 was the oldest earthquake that damaged Lima. The tsunami height was assigned as 24 m in Callao and 1-2 m in Miyagi prefecture in Japan by Soloviev and Go (1975). Dorbath et al. (1990) studied historical earthquakes in Peru and estimated that the 1586 earthquake was similar to the 1974 event (Mw 8.1) with source length of 175 km. They referred two different tsunami heights, 3. 7m and 24 m, in Callao, and judged that the latter was exaggerated. Okal et al. (2006) could not make a source model to explain both tsunami heights in Callao and Japan. More recently, Butler et al. (2017) estimated the age of coral boulders in Hawaii as AD 1572 +/- 21, speculated the tsunami source in Aleutians, and attributed it to the source of the 1586 tsunami in Japan. Historical tsunamis, both near-field and far-field, have been documented along the Sanriku coast since 1586 (e.g., Watanabe, 1998). However, there is no written document for the 1586 tsunami (Tsuji et al., 2013). Ninomiya (1960) compiled the historical tsunami records on the Sanriku coast soon after the 1960 Chilean tsunami, and correlated the legend of tsunami in Tokura with the 1586 Peruvian earthquake, although he noted that the dates were different. About the legend, he referred to Kunitomi(1933) who compiled historical tsunami data after the 1933 Showa Sanriku tsunami. Kunitomi referred to "Tsunami history of Miyagi prefecture" published after the 1896 Meiji Sanriku tsunami. "Tsunami history" described the earthquake and tsunami damage of Tensho earthquake on January 18 (Gregorian),1586 in central Japan, and correlated the tsunami legend in Tokura on June 30, 1586 (G). Following the 2011 Tohoku tsunami, tsunami legend in Tokura was studied again (Ebina, 2015). A local person published a story he heard from his grandfather that many small valleys were named following the 1611 tsunami, which inundated further inland than the 2011 tsunami. Ebina (2015), based on historical documents, estimated that the legend existed around 1750. From the above research, the tsunami legend in Tokura is unlikely from the Peruvian earthquake. Hence the 1586 tsunami was not an orphan tsunami, but rather a ghost or fake tsunami. The legend simply mentioned about tsunami, but the tsunami heights were speculated as 1-2 m (Soloviev and Go) or 2 - 2.5 m (NOAA tsunami DB).

CMOS Active-Pixel Image Sensor With Simple Floating Gates

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

1996-01-01

Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

Field Observations Of The 29 September Tsunami In American Samoa: Spatial Variability And Indications Of Strong Return Flow

NASA Astrophysics Data System (ADS)

Jaffe, B. E.; Richmond, B. M.; Gelfenbaum, G. R.; Watt, S.; Apotsos, A. A.; Buckley, M. L.; Dudley, W. C.; Peck, B.

2009-12-01

The 29 September 2009 tsunami caused 181 fatalities and displaced more than 5000 people on the islands of Samoa, American Samoa, and Tonga. This is the first tsunami to cause significant damage and fatalities on U.S. soil in more than 30 years. Scientists from around the world quickly mobilized to help document the tsunami water levels before this ephemeral data was forever lost as recovery activities and natural processes overtook the effected area. A USGS team collected data in American Samoa from October 6-22 and November 5-12, 2009. The tsunami was large, reaching elevations of greater than 15 m, however wave heights and devastation varied from village to village in American Samoa. Even within villages, some structures were completely destroyed, some flooded and left standing, and others barely touched. Wave heights, flow depths, runup heights, inundation distances, and flow directions were collected for use in ground-truthing inundation models. The team also collected nearshore bathymetry, topography and reef flat elevation, sediment samples, and documented the distribution and characteristics of both sand and boulder deposits. Eyewitness accounts of the tsunami were also videotaped. One striking aspect of this tsunami was the abundance of indicators of strong return flow. For example at Poloa in the northwest of Tutuila, where the runup was greater than 11 m along a 300-m stretch of coast and flow depths exceeded 4 m, the coral reef flat was strewn with debris including chairs, desks, and books from a school. On land, River channels were excavated and new channels formed as return flow scoured sediment and transported it offshore. Possible causes for the strong return flow and the relation between the stength of the return flow, inundation distance, and runup in American Samoa are presented. These relationships and others based on data collected by field survey teams will ultimately reduce loss of life and destruction from tsunamis in the Pacific and elsewhere.

Tsunami Evacuation Exercises: the Case of Heraklion, Crete Isl., Greece

NASA Astrophysics Data System (ADS)

Triantafyllou, I.; Charalampakis, M.; Bocchini, G. M.; Novikova, T.; Papadopoulos, G. A.

2016-12-01

Effective tsunami evacuation requires appropriate awareness as regards good shelters selection. Field exercises may improve public awareness. A field exercise was organized in Heraklion, Crete Isl., in 2016. The area is part of the Hellenic Arc which is the most active structure in the Mediterranean. Large earthquakes triggered tsunamis that hit Heraklion in the past, such in AD 1303. After selecting various fault models, simulation of the 1303 tsunami showed important inundation zone in Heraklion. For the exercise needs a team of 30 volunteers was divided in 3 groups of 10 people each. Everyone was equipped with a mobile phone and a GPS device. The 3 groups were gathered in 3 coastal spots Heraklion situated 400 m apart each other. The scenario was that immediately after receiving in their mobile a tsunami warning message they will set on their personal GPS device and start evacuating inland on the best way they believed to do so. In each group, only 5 out of 10 volunteers were notified beforehand that the Eleftherias Square, located inland at distance satisfying evacuation needs in case of repeat of the 1303 tsunami, would be a good shelter to go. Using the Road Graph Plugin of QGIS, we calculated the shortest path distances which found equal to 800, 700 and 680 m. Adopting average velocity of 3 km/h we found that these distances can be covered within 18, 16 and 15 min, respectively. The routes towards the settlement spots as well as the times needed to arrive there by each one of the 30 volunteers were recorded by their personal GPS devices. The processing of the GPS tracks and their comparison with the theoretical routes and times showed good evacuation performance which is encouraging for the next phases of the Heraklion tsunami hazard mitigation program. This is contribution to the EU-FP7 projects ZIP (Zooming In between Plates, grant no: 604713, 2013) and ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe), grant no: 603839, 2013.

Potential predecessors of the 2004 Indian Ocean Tsunami — Sedimentary evidence of extreme wave events at Ban Bang Sak, SW Thailand

NASA Astrophysics Data System (ADS)

Brill, D.; Brückner, H.; Jankaew, K.; Kelletat, D.; Scheffers, A.; Scheffers, S.

2011-08-01

Where historical records are short and/or fragmentary, geological evidence is an important tool to reconstruct the recurrence rate of extreme wave events (tsunamis and/or storms). This is particularly true for those coastal zones around the Indian Ocean, where predecessors of similar magnitude as the 2004 Indian Ocean Tsunami (IOT) have not been reported by written sources. In this context, the sedimentary record of the Holocene coastal plain of Ban Bang Sak (Phang-nga province, Thailand) provides evidence of multiple prehistoric coastal flooding events in the form of allochthonous sand beds, which were radiocarbon dated to 700-500, 1350-1180, and younger than 2000 cal BP. The layers were assigned to high-energy events of marine origin, which could be either tsunamis or tropical storms, by means of granulometry, geochemistry, vertical structure, and macrofossil content. Although no landfall of a strong storm has occurred in the last 150 years of meteorological data recording, cyclones cannot be ruled out for the last centuries and millennia. However, discrimination between tsunami and storm origin was mainly based on the comparison of the palaeoevent beds with the local deposit of the IOT, which revealed similar characteristics in regard to spatial extend and sediment properties. Furthermore, the youngest palaeoevent correlates with contemporaneous deposits from Thailand and more distant coasts. Hence, we relate it to a basin wide tsunami which took place 700-500 years ago. For the sediments of older extreme events, deposited between 2000 and 1180 cal BP, we found no unambiguous counterparts at other sites; nevertheless, at least for now, they are treated as tsunami candidates.

A Preliminary Tsunami vulnerability analysis for Bakirkoy district in Istanbul

NASA Astrophysics Data System (ADS)

Tufekci, Duygu; Lutfi Suzen, M.; Cevdet Yalciner, Ahmet; Zaytsev, Andrey

2016-04-01

Resilience of coastal utilities after earthquakes and tsunamis has major importance for efficient and proper rescue and recovery operations soon after the disasters. Vulnerability assessment of coastal areas under extreme events has major importance for preparedness and development of mitigation strategies. The Sea of Marmara has experienced numerous earthquakes as well as associated tsunamis. There are variety of coastal facilities such as ports, small craft harbors, and terminals for maritime transportation, water front roads and business centers mainly at North Coast of Marmara Sea in megacity Istanbul. A detailed vulnerability analysis for Yenikapi region and a detailed resilience analysis for Haydarpasa port in Istanbul have been studied in previously by Cankaya et al., (2015) and Aytore et al., (2015) in SATREPS project. In this study, the methodology of vulnerability analysis under tsunami attack given in Cankaya et al., (2015) is modified and applied to Bakirkoy district of Istanbul. Bakirkoy district is located at western part of Istanbul and faces to the North Coast of Marmara Sea from 28.77oE to 28.89oE. High resolution spatial dataset of Istanbul Metropolitan Municipality (IMM) is used and analyzed. The bathymetry and topography database and the spatial dataset containing all buildings/structures/infrastructures in the district are collated and utilized for tsunami numerical modeling and following vulnerability analysis. The tsunami parameters from deterministically defined worst case scenarios are computed from the simulations using tsunami numerical model NAMI DANCE. The vulnerability assessment parameters in the district according to vulnerability and resilience are defined; and scored by implementation of a GIS based TVA with appropriate MCDA methods. The risk level is computed using tsunami intensity (level of flow depth from simulations) and TVA results at every location in Bakirkoy district. The preliminary results are presented and discussed. Acknowledgements: Partial support by Japan-Turkey Joint Research Project by JICA on earthquakes and tsunamis in Marmara Region in (JICA SATREPS - MarDiM Project), 603839 ASTARTE Project of EU, UDAP-C-12-14 project of AFAD, Turkey, 108Y227, 113M556, 213M534 projects of TUBITAK Turkey, RAPSODI (CONCERT_Dis-021) of CONCERT-Japan Joint Call and Istanbul Metropolitan Municipality are acknowledged.

Tsunami geology in paleoseismology

USGS Publications Warehouse

Yuichi Nishimura,; Jaffe, Bruce E.

2015-01-01

The 2004 Indian Ocean and 2011 Tohoku-oki disasters dramatically demonstrated the destructiveness and deadliness of tsunamis. For the assessment of future risk posed by tsunamis it is necessary to understand past tsunami events. Recent work on tsunami deposits has provided new information on paleotsunami events, including their recurrence interval and the size of the tsunamis (e.g. [187–189]). Tsunamis are observed not only on the margin of oceans but also in lakes. The majority of tsunamis are generated by earthquakes, but other events that displace water such as landslides and volcanic eruptions can also generate tsunamis. These non-earthquake tsunamis occur less frequently than earthquake tsunamis; it is, therefore, very important to find and study geologic evidence for past eruption and submarine landslide triggered tsunami events, as their rare occurrence may lead to risks being underestimated. Geologic investigations of tsunamis have historically relied on earthquake geology. Geophysicists estimate the parameters of vertical coseismic displacement that tsunami modelers use as a tsunami's initial condition. The modelers then let the simulated tsunami run ashore. This approach suffers from the relationship between the earthquake and seafloor displacement, the pertinent parameter in tsunami generation, being equivocal. In recent years, geologic investigations of tsunamis have added sedimentology and micropaleontology, which focus on identifying and interpreting depositional and erosional features of tsunamis. For example, coastal sediment may contain deposits that provide important information on past tsunami events [190, 191]. In some cases, a tsunami is recorded by a single sand layer. Elsewhere, tsunami deposits can consist of complex layers of mud, sand, and boulders, containing abundant stratigraphic evidence for sediment reworking and redeposition. These onshore sediments are geologic evidence for tsunamis and are called ‘tsunami deposits’ (Figs. 26 and 27). Tsunami deposits can be classified into two groups: modern tsunami deposits and paleotsunami deposits. A modern tsunami deposit is a deposit whose source event is known. A paleotsunami deposit is a deposit whose age is estimated and has a source that is either inferred to be a historical event or is unknown.

Extraction of the gate capacitance coupling coefficient in floating gate non-volatile memories: Statistical study of the effect of mismatching between floating gate memory and reference transistor in dummy cell extraction methods

NASA Astrophysics Data System (ADS)

Rafhay, Quentin; Beug, M. Florian; Duane, Russell

2007-04-01

This paper presents an experimental comparison of dummy cell extraction methods of the gate capacitance coupling coefficient for floating gate non-volatile memory structures from different geometries and technologies. These results show the significant influence of mismatching floating gate devices and reference transistors on the extraction of the gate capacitance coupling coefficient. In addition, it demonstrates the accuracy of the new bulk bias dummy cell extraction method and the importance of the β function, introduced recently in [Duane R, Beug F, Mathewson A. Novel capacitance coupling coefficient measurement methodology for floating gate non-volatile memory devices. IEEE Electr Dev Lett 2005;26(7):507-9], to determine matching pairs of floating gate memory and reference transistor.

Development of Tsunami Numerical Model Considering the Disaster Debris such as Cars, Ships and Collapsed Buildings

NASA Astrophysics Data System (ADS)

Kozono, Y.; Takahashi, T.; Sakuraba, M.; Nojima, K.

2016-12-01

A lot of debris by tsunami, such as cars, ships and collapsed buildings were generated in the 2011 Tohoku tsunami. It is useful for rescue and recovery after tsunami disaster to predict the amount and final position of disaster debris. The transport form of disaster debris varies as drifting, rolling and sliding. These transport forms need to be considered comprehensively in tsunami simulation. In this study, we focused on the following three points. Firstly, the numerical model considering various transport forms of disaster debris was developed. The proposed numerical model was compared with the hydraulic experiment by Okubo et al. (2004) in order to verify transport on the bottom surface such as rolling and sliding. Secondly, a numerical experiment considering transporting on the bottom surface and drifting was studied. Finally, the numerical model was applied for Kesennuma city where serious damage occurred by the 2011 Tohoku tsunami. In this model, the influence of disaster debris was considered as tsunami flow energy loss. The hydraulic experiments conducted in a water tank which was 10 m long by 30 cm wide. The gate confined water in a storage tank, and acted as a wave generator. A slope was set at downstream section. The initial position of a block (width: 3.2 cm, density: 1.55 g/cm3) assuming the disaster debris was placed in front of the slope. The proposed numerical model simulated well the maximum transport distance and the final stop position of the block. In the second numerical experiment, the conditions were the same as the hydraulic experiment, except for the density of the block. The density was set to various values (from 0.30 to 4.20 g/cm3). This model was able to estimate various transport forms including drifting and sliding. In the numerical simulation of the 2011 Tohoku tsunami, the condition of buildings was modeled as follows: (i)the resistance on the bottom using Manning roughness coefficient (conventional method), and (ii)structure of buildings with collapsing and washing-away due to tsunami wave pressure. In this calculation, disaster debris of collapsed buildings, cars and ships was considered. As a result, the proposed model showed that it is necessary to take the disaster debris into account in order to predict tsunami inundation accurately.

What is the fault that has generated the earthquake on 8 September 1905 in Calabria, Italy? Source models compared by tsunami data

NASA Astrophysics Data System (ADS)

Pagnoni, Gianluca; Armigliato, Alberto; Tinti, Stefano; Loreto, Maria Filomena; Facchin, Lorenzo

2014-05-01

The earthquake that the 8 September 1905 hit Calabria in southern Italy was the second Italian earthquake for magnitude in the last century. It destroyed many villages along the coast of the Gulf of Sant'Eufemia, caused more than 500 fatalities and has also generated a tsunami with non-destructive effects. The historical reports tell us that the tsunami caused major damage in the villages of Briatico, Bivona, Pizzo and Vibo Marina, located in the south part of the Sant'Eufemia gulf and minor damage to Tropea and to Scalea, this one being village located about 100 km far from the epicenter. Other reports include accounts of fishermen at sea during the tsunami. Further, the tsunami is visible on tide gauge records in Messina, Sicily, in Naples and in Civitavecchia, a harbour located to the north of Rome (Platania, 1907) In spite of the attention devoted by researchers to this case, until now, like for other tsunamigenic Italian earthquakes, the genetic structure of the earthquake is still not identified and debate is still open. In this context, tsunami simulations can provide contributions useful to find the source model more consistent with observational data. This approach was already followed by Piatanesi and Tinti (2002), who carried out numerical simulations of tsunamis from a number of local sources. In the last decade studies on this seismogenic area were int ensified resulting in new estimates for the 1905 earthquake magnitude (7.1 according to the CPTI11 catalogue) and in the suggestion of new source models. By using an improved tsunami simulation model, more accurate bathymetry data, this work tests the source models investigated by Piatanesi and Tinti (2002) and in addition the new fault models proposed by Cucci and Tertulliani (2010) and by Loreto et al. (2013). The simulations of the tsunami are calculated by means of the code, UBO-TSUFD, that solves the linear equations of Navier-Stokes in approximation of shallow water with the finite-difference technique, while the initial conditions are calculated via Okada's formula. The key-result used to test the models against the data is the maximum height of the tsunami calculated close to the shore at a minimum depth of 5m corrected using the values of the initial coseismic field deformation.

Mathematical modelling of tsunami impacts on critical infrastructures: exposure and severity associated with debris transport at Sines port, Portugal.

NASA Astrophysics Data System (ADS)

Conde, Daniel; Baptista, Maria Ana; Sousa Oliveira, Carlos; Ferreira, Rui M. L.

2015-04-01

Global energy production is still significantly dependant on the coal supply chain, justifying huge investments on building infrastructures, capable of stocking very large quantities of this natural resource. Most of these infrastructures are located at deep-sea ports and are therefore exposed to extreme coastal hazards, such as tsunami impacts. The 2011 Tohoku tsunami is reported to have inflicted severe damage to Japan's coal-fired power stations and related infrastructure. Sines, located in the Portuguese coast, hosts a major commercial port featuring an exposed coal stockpile area extending over more than 24 ha and a container terminal currently under expansion up to 100ha. It is protected against storm surges but tsunamis have not been considered in the design criteria. The dominant wind-generated wave direction is N to NW, while the main tsunamigenic faults are located S to SW of the port. This configuration potentially exposes sensitive facilities, such as the new terminal container and the coal stockpile area. According to a recent revision of the national tsunami catalogue (Baptista, 2009), Portugal has been affected by numerous major tsunamis over the last two millennia, with the most notorious event being the Great Lisbon Earthquake and Tsunami occurred on the 1st November 1755. The aim of this work is to simulate the open ocean propagation and overland impact of a tsunami on the Sines port, similar to the historical event of 1755, based on the different tsunamigenic faults and magnitudes proposed in the current literature. Open ocean propagation was modelled with standard simulation tools like TUNAMI and GeoClaw. Near-shore and overland propagation was carried out using a recent 2DH mathematical model for solid-fluid flows, STAV-2D from CERIS-IST (Ferreira et al., 2009; Canelas, 2013). STAV-2D is particularly suited for tsunami propagation over complex and morphodynamic geometries, featuring a discretization scheme based on a finite-volume method using a flux-splitting technique with a reviewed Roe-Riemann solver and appropriate source-term formulations to ensure full conservativeness. Additionally, STAV-2D features Lagrangian-Eulerian coupling enabling solid transport simulation under both continuum and discrete approaches, and has been validated with both laboratory data and paleo-tsunami evidence (Conde, 2013a; Conde, 2013b). The interactions between the inundating flow and coal stockpiles or natural mobile bed reaches were simulated using a continuum debris-flow approach, featuring fractional solid transport, while the containers at the new terminal were advected with an explicit Lagrangian method. The meshwork employed at the port models the existing geometry and structures in great detail, enabling explicitly resolved interactions between the current infrastructure and the overland propagating tsunami. The obtained preliminary results suggest that several structures, some of them critical in a nationwide context, are exposed to tsunami actions. The coal deposition pattern and the final location of monitored containers were determined for two magnitude scenarios (8.5 Mw and 9.5 Mw) in the case of a tsunami generated at the Horseshoe fault and one magnitude scenario (9.5 Mw) for a tsunami generated at the Gorringe bank. The inland washing of the coal stockpiles may impose great loss of both economical and environmental value, while the impact of large mobile debris, such as the containers in the terminal area, significantly increases the severity of infrastructural damage. Acknowledgements This work was partially funded by FEDER, program COMPETE, and by national funds through the Portuguese Foundation for Science and Technology (FCT) with project RECI/ECM-HID/0371/2012. References Baptista M.A. & Miranda, J.M. (2009), Revision of the Portuguese catalog of tsunamis. Nat. Hazards Earth Syst. Sci., 9, 25-42. Canelas, R.; Murillo, J. & Ferreira, R.M.L. (2013), Two-dimensional depth-averaged modelling of dam-break flows over mobile beds. Vol 51(4) pp. 392-407. Conde, D. A. S.; Baptista, M. A. V.; Sousa Oliveira, C. & Ferreira, R. M. L. (2013a), A shallow-flow model for the propagation of tsunamis over complex geometries and mobile beds, Nat. Hazards Earth Syst. Sci., 13, 2533-2542. Conde, D. A. S.; Canelas, R. B.; Sousa Oliveira, C. & Ferreira, R. M. L. (2013b), Mathematical modelling of transport of coal stockpiles by a tsunami at Sines port, 8th International SedNet Conference 2013, Lisbon, Portugal. Ferreira, R. M. L.; Franca, M. J.; Leal, J. G. & Cardoso, A. H. (2009), Mathematical modelling of shallow flows: Closure models drawn from grain-scale mechanics of sediment transport and flow hydrodynamics, Can. J. Civil. Eng., 36, 1604-1621, 2009.

Tsunami Waves Joint Inversion Using Tsunami Inundation, Tsunami Deposits Distribution and Marine-Terrestrial Sediment Signal in Tsunami Deposit

NASA Astrophysics Data System (ADS)

Tang, H.; WANG, J.

2017-12-01

Population living close to coastlines is increasing, which creates higher risks due to coastal hazards, such as the tsunami. However, the generation of a tsunami is not fully understood yet, especially for paleo-tsunami. Tsunami deposits are one of the concrete evidence in the geological record which we can apply for studying paleo-tsunami. The understanding of tsunami deposits has significantly improved over the last decades. There are many inversion models (e.g. TsuSedMod, TSUFLIND, and TSUFLIND-EnKF) to study the overland-flow characteristics based on tsunami deposits. However, none of them tries to reconstruct offshore tsunami wave characteristics (wave form, wave height, and length) based on tsunami deposits. Here we present a state-of-the-art inverse approach to reconstruct offshore tsunami wave based on the tsunami inundation data, the spatial distribution of tsunami deposits and Marine-terrestrial sediment signal in the tsunami deposits. Ensemble Kalman Filter (EnKF) Method is used for assimilating both sediment transport simulations and the field observation data. While more computationally expensive, the EnKF approach potentially provides more accurate reconstructions for tsunami waveform. In addition to the improvement of inversion results, the ensemble-based method can also quantify the uncertainties of the results. Meanwhile, joint inversion improves the resolution of tsunami waves compared with inversions using any single data type. The method will be tested by field survey data and gauge data from the 2011 Tohoku tsunami on Sendai plain area.

Coordinating Post-Tsunami Field Surveys in the us

NASA Astrophysics Data System (ADS)

Kong, L. S.; Chiesa, C.; Dunbar, P. K.; Huart, J.; Richards, K.; Shulters, M.; Stein, A.; Tamura, G.; Wilson, R. I.; Young, E.

2011-12-01

Post-tsunami scientific field surveys are critical for improving the understanding of tsunamis and developing tools and programs to mitigate their effects. After a destructive tsunami, international, national, and local tsunami scientists need to gather information, much of which is perishable or degrades significantly with time. An influx of researchers can put stress on countries already overwhelmed by humanitarian response to the disaster and by the demands of emergency management and other support agencies. In the United States, in addition to university research scientists, government agencies such as the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geologic Survey (USGS), and state/territorial emergency management agencies and geological surveys endeavor to collect physical and social science data to better understand the physics of tsunamis and the impact they have on coastal communities and ecosystems. After a Presidential Major Disaster Declaration, the Federal Emergency Management Agency (FEMA) Joint Field Office works with state/territory emergency management agencies to coordinate response to disasters. In the short-term, the collection and immediate sharing of data enable decision-making that better organizes and deploys often-limited resources to the areas most critically in need of response; and in the long-term, improves recovery planning that will mitigate the losses from the next tsunami. Recent tsunamis have emphasized the need for improved coordination of data collection among scientists and federal, state, and local emergency managers. Improved coordination will ensure data collection efforts are carried out in a safe, secure, efficient, and timely manner. To improve coordination of activities that will better integrate the scientific investigations with government response, the US National Tsunami Hazard Mitigation Program and Pacific Risk Management 'Ohana (PRiMO) are working together to develop a consistent framework for a tsunami technical clearinghouse (TTC). The goals of the TTC, which would include at a minimum an electronic information server but could also include a physical location, are to: 1) assist in the response to, damage assessment of, and early recovery from the natural disaster; 2) facilitate researcher access to the affected areas; and 3) contribute to the capture of valuable and perishable data. The Working Group, composed of representatives from NOAA, USGS, FEMA, and state and local emergency managers and geoscientists, will engage with other stakeholders and the science community to review existing national standard operating procedures for post-tsunami scientific field surveys and data collection, as well as make recommendations for domestic application. The outcomes are intended to propose a national structure that can be consistently implemented within each state and territory.

Tsunami-driven gravity waves in the presence of vertically varying background and tidal wind structures

NASA Astrophysics Data System (ADS)

Laughman, B.; Fritts, D. C.; Lund, T. S.

2017-05-01

Many characteristics of tsunami-driven gravity waves (TDGWs) enable them to easily propagate into the thermosphere and ionosphere with appreciable amplitudes capable of producing detectable perturbations in electron densities and total electron content. The impact of vertically varying background and tidal wind structures on TDGW propagation is investigated with a series of idealized background wind profiles to assess the relative importance of wave reflection, critical-level approach, and dissipation. These numerical simulations employ a 2-D nonlinear anelastic finite-volume neutral atmosphere model which accounts for effects accompanying vertical gravity wave (GW) propagation such as amplitude growth with altitude. The GWs are excited by an idealized tsunami forcing with a 50 cm sea surface displacement, a 400 km horizontal wavelength, and a phase speed of 200 ms-1 consistent with previous studies of the tsunami generated by the 26 December 2004 Sumatra earthquake. Results indicate that rather than partial reflection and trapping, the dominant process governing TDGW propagation to thermospheric altitudes is refraction to larger and smaller vertical scales, resulting in respectively larger and smaller vertical group velocities and respectively reduced and increased viscous dissipation. Under all considered background wind profiles, TDGWs were able to attain ionospheric altitudes with appreciable amplitudes. Finally, evidence of nonlinear effects is observed and the conditions leading to their formation is discussed.

Tsunami simulation method initiated from waveforms observed by ocean bottom pressure sensors for real-time tsunami forecast; Applied for 2011 Tohoku Tsunami

NASA Astrophysics Data System (ADS)

Tanioka, Yuichiro

2017-04-01

After tsunami disaster due to the 2011 Tohoku-oki great earthquake, improvement of the tsunami forecast has been an urgent issue in Japan. National Institute of Disaster Prevention is installing a cable network system of earthquake and tsunami observation (S-NET) at the ocean bottom along the Japan and Kurile trench. This cable system includes 125 pressure sensors (tsunami meters) which are separated by 30 km. Along the Nankai trough, JAMSTEC already installed and operated the cable network system of seismometers and pressure sensors (DONET and DONET2). Those systems are the most dense observation network systems on top of source areas of great underthrust earthquakes in the world. Real-time tsunami forecast has depended on estimation of earthquake parameters, such as epicenter, depth, and magnitude of earthquakes. Recently, tsunami forecast method has been developed using the estimation of tsunami source from tsunami waveforms observed at the ocean bottom pressure sensors. However, when we have many pressure sensors separated by 30km on top of the source area, we do not need to estimate the tsunami source or earthquake source to compute tsunami. Instead, we can initiate a tsunami simulation from those dense tsunami observed data. Observed tsunami height differences with a time interval at the ocean bottom pressure sensors separated by 30 km were used to estimate tsunami height distribution at a particular time. In our new method, tsunami numerical simulation was initiated from those estimated tsunami height distribution. In this paper, the above method is improved and applied for the tsunami generated by the 2011 Tohoku-oki great earthquake. Tsunami source model of the 2011 Tohoku-oki great earthquake estimated using observed tsunami waveforms, coseimic deformation observed by GPS and ocean bottom sensors by Gusman et al. (2012) is used in this study. The ocean surface deformation is computed from the source model and used as an initial condition of tsunami simulation. By assuming that this computed tsunami is a real tsunami and observed at ocean bottom sensors, new tsunami simulation is carried out using the above method. The station distribution (each station is separated by 15 min., about 30 km) observed tsunami waveforms which were actually computed from the source model. Tsunami height distributions are estimated from the above method at 40, 80, and 120 seconds after the origin time of the earthquake. The Near-field Tsunami Inundation forecast method (Gusman et al. 2014) was used to estimate the tsunami inundation along the Sanriku coast. The result shows that the observed tsunami inundation was well explained by those estimated inundation. This also shows that it takes about 10 minutes to estimate the tsunami inundation from the origin time of the earthquake. This new method developed in this paper is very effective for a real-time tsunami forecast.

The Role of Earth Science in Oregon’s Tsunami Preparedness (Invited)

NASA Astrophysics Data System (ADS)

Priest, G. R.

2009-12-01

Earth science played a critical role in understanding the scope of Oregon’s tsunami hazard. When in the early 1990’s earth scientists communicated to stakeholders the seriousness of the threat posed by local Cascadia subduction zone tsunamis, tsunami preparedness began to rise in priority at all levels of government. Hard field evidence in the form of prehistoric tsunami deposits was a critical component in making the hazard “real” to local governments. State-produced tsunami inundation maps derived from numerical simulations gave decision makers and educators reliable tools to illustrate the spatial scope of the hazard. These maps allowed local cities to plan for evacuation and empowered the State of Oregon to begin “hard” mitigation by limiting new construction of critical facilities seaward of a regulatory inundation line. “Entering” and “Leaving” tsunami hazard zone signs were placed along the Oregon Coast Highway where it dips below this inundation line as means of raising awareness of both the local and transient populations. When detailed inundation studies and derivative evacuation maps were produced for individual communities, State scientists sought advice from local officials at every stage, giving them ownership of the final products. This sense of ownership gave decision makers much greater confidence in the maps and turned many skeptics into passionate advocates. This network of advocates has, over time, resulted in local jurisdictions taking substantive preparedness actions such as replacing critical evacuation bridges, starting networks of emergency response volunteers, and moving critical structures like schools and fire stations. One place that earth science has some difficulty is in communicating probability and uncertainty. For example, the State of Oregon is currently producing new maps that depict uncertainty of tsunami flooding from a future Cascadia subduction zone earthquake. These maps show a range of inundation lines that reflect the relative confidence level (percentage) that a local Cascadia tsunami will NOT exceed each line. In the first of these studies at Cannon Beach, Oregon (Priest et al., 2009) the 90th percentile flood level was only about half to two-thirds as high as the 99th percentile. On the northern Oregon coast Cascadia recurrence is ~500 years, so a percentile map depicts spatial uncertainty of inundation for that event. A Cascadia tsunami approximating the 99th percentile confidence level is no doubt a rare event, but how rare we really do not know. We suspect from offshore turbidite data that only one of these extreme events may have occurred in the last 10,000 years. When the map and underlying data were presented to local officials, they had some difficulty in understanding how to use the information. Erring on the side of caution, they chose the 99th percentile line for evacuation planning but this decision greatly limited available evacuation sites. Cost may make a similarly conservative decision inappropriate for use in building codes or for design of vertical evacuation structures. REFERENCE Priest, G.R.; Goldfinger C.; Wang, K.; Witter, R.C.; Zhang; Y., Baptista, A.M. (2009) Tsunami hazard assessment of the Northern Oregon coast: a multi-deterministic approach tested at Cannon Beach, Clatsop County, Oregon. Oregon Dept. Geol. Mineral Industries Special Paper 41.

Tsunamis hazard assessment and monitoring for the Back Sea area

NASA Astrophysics Data System (ADS)

Partheniu, Raluca; Ionescu, Constantin; Constantin, Angela; Moldovan, Iren; Diaconescu, Mihail; Marmureanu, Alexandru; Radulian, Mircea; Toader, Victorin

2016-04-01

NIEP has improved lately its researches regarding tsunamis in the Black Sea. As part of the routine earthquake and tsunami monitoring activity, the first tsunami early-warning system in the Black Sea has been implemented in 2013 and is active during these last years. In order to monitor the seismic activity of the Black Sea, NIEP is using a total number of 114 real time stations and 2 seismic arrays, 18 of the stations being located in Dobrogea area, area situated in the vicinity of the Romanian Black Sea shore line. Moreover, there is a data exchange with the Black Sea surrounding countries involving the acquisition of real-time data for 17 stations from Bulgaria, Turkey, Georgia and Ukraine. This improves the capability of the Romanian Seismic Network to monitor and more accurately locate the earthquakes occurred in the Black Sea area. For tsunamis monitoring and warning, a number of 6 sea level monitoring stations, 1 infrasound barometer, 3 offshore marine buoys and 7 GPS/GNSS stations are installed in different locations along and near the Romanian shore line. In the framework of ASTARTE project, few objectives regarding the seismic hazard and tsunami waves height assessment for the Black Sea were accomplished. The seismic hazard estimation was based on statistical studies of the seismic sources and their characteristics, compiled using different seismic catalogues. Two probabilistic methods were used for the evaluation of the seismic hazard, the Cornell method, based on the Gutenberg Richter distribution parameters, and Gumbel method, based on extremes statistic. The results show maximum values of possible magnitudes and their recurrence periods, for each seismic source. Using the Tsunami Analysis Tool (TAT) software, a set of tsunami modelling scenarios have been generated for Shabla area, the seismic source that could mostly affect the Romanian shore. These simulations are structured in a database, in order to set maximum possible tsunami waves that could be generated and to establish minimum magnitude values that could trigger tsunamis in this area. Some particularities of Shabla source are: past observed magnitudes > 7 and a recurrence period of 175 years. Some other important objectives of NIEP are to continue the monitoring of the seismic activity of the Black Sea, to improve the data base of the tsunami simulations for this area, near real time fault plane solution estimations used for the warning system, and to add new seismic, GPS/GNSS and sea level monitoring equipment to the existing network. Acknowledgements: This work was partially supported by the FP7 FP7-ENV2013 6.4-3 "Assessment, Strategy And Risk Reduction For Tsunamis in Europe" (ASTARTE) Project 603839/2013 and PNII, Capacity Module III ASTARTE RO Project 268/2014. This work was partially supported by the "Global Tsunami Informal Monitoring Service - 2" (GTIMS2) Project, JRC/IPR/2015/G.2/2006/NC 260286, Ref. Ares (2015)1440256 - 01.04.2015.

Aeroelastic impact of above-rated wave-induced structural motions on the near-wake stability of a floating offshore wind turbine rotor

NASA Astrophysics Data System (ADS)

Rodriguez, Steven; Jaworski, Justin

2017-11-01

The impact of above-rated wave-induced motions on the stability of floating offshore wind turbine near-wakes is studied numerically. The rotor near-wake is generated using a lifting-line free vortex wake method, which is strongly coupled to a finite element solver for kinematically nonlinear blade deformations. A synthetic time series of relatively high-amplitude/high-frequency representative of above-rated conditions of the NREL 5MW referece wind turbine is imposed on the rotor structure. To evaluate the impact of these above-rated conditions, a linear stability analysis is first performed on the near wake generated by a fixed-tower wind turbine configuration at above-rated inflow conditions. The platform motion is then introduced via synthetic time series, and a stability analysis is performed on the wake generated by the floating offshore wind turbine at the same above-rated inflow conditions. The stability trends (disturbance modes versus the divergence rate of vortex structures) of the two analyses are compared to identify the impact that above-rated wave-induced structural motions have on the stability of the floating offshore wind turbine wake.

Post Fukushima tsunami simulations for Malaysian coasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koh, Hock Lye, E-mail: kohhl@ucsiuniversity.edu.my; Teh, Su Yean, E-mail: syteh@usm.my; Abas, Mohd Rosaidi Che

The recent recurrences of mega tsunamis in the Asian region have rekindled concern regarding potential tsunamis that could inflict severe damage to affected coastal facilities and communities. The 11 March 2011 Fukushima tsunami that crippled nuclear power plants in Northern Japan has further raised the level of caution. The recent discovery of petroleum reserves in the coastal water surrounding Malaysia further ignites the concern regarding tsunami hazards to petroleum facilities located along affected coasts. Working in a group, federal government agencies seek to understand the dynamics of tsunami and their impacts under the coordination of the Malaysian National Centre formore » Tsunami Research, Malaysian Meteorological Department. Knowledge regarding the generation, propagation and runup of tsunami would provide the scientific basis to address safety issues. An in-house tsunami simulation models known as TUNA has been developed by the authors to assess tsunami hazards along affected beaches so that mitigation measures could be put in place. Capacity building on tsunami simulation plays a critical role in the development of tsunami resilience. This paper aims to first provide a simple introduction to tsunami simulation towards the achievement of tsunami simulation capacity building. The paper will also present several scenarios of tsunami dangers along affected Malaysia coastal regions via TUNA simulations to highlight tsunami threats. The choice of tsunami generation parameters reflects the concern following the Fukushima tsunami.« less

Casting Control of Floating-films into Ribbon-shape Structure by modified Dynamic FTM

NASA Astrophysics Data System (ADS)

Tripathi, A.; Pandey, M.; Nagamatsu, S.; Pandey, S. S.; Hayase, S.; Takashima, W.

2017-11-01

We have developed a new method to obtain Ribbon-shaped floating films via dynamic casting of floating-film and transfer method (dynamic-FTM). Dynamic-FTM is a unique method to prepare oriented thin-film of conjugated polymers (CPs) which is quick and easy. This method has several advantages as compared to the other conventional casting procedure to prepare oriented CP films. In the conventional dynamic FTM appearance of large scale circular orientation poses difficulty not only for practical applications but also hinders the detailed analysis of the orientation mechanism. In this present work, pros and cons of this newly proposed ribbon-shaped floating-film have been discussed in detail from those of the conventional floating-film prepared by dynamic-FTM.

Tsunami Science for Society

NASA Astrophysics Data System (ADS)

Bernard, E. N.

2014-12-01

As the decade of mega-tsunamis has unfolded with new data, the science of tsunami has advanced at an unprecedented pace. Our responsibility to society should guide the use of these new scientific discoveries to better prepare society for the next tsunami. This presentation will focus on the impacts of the 2004 and 2011 tsunamis and new societal expectations accompanying enhanced funding for tsunami research. A list of scientific products, including tsunami hazard maps, tsunami energy scale, real-time tsunami flooding estimates, and real-time current velocities in harbors will be presented to illustrate society's need for relevant, easy to understand tsunami information. Appropriate use of these tsunami scientific products will be presented to demonstrate greater tsunami resilience for tsunami threatened coastlines. Finally, a scientific infrastructure is proposed to ensure that these products are both scientifically sound and represent today's best practices to protect the scientific integrity of the products as well as the safety of coastal residents.

Catamaran or semi-submersible for floating platform - selection of a better design

NASA Astrophysics Data System (ADS)

Qasim, Idrees; Gao, Liangtian; Peng, Duojin; Liu, Bo

2018-02-01

With nonstop advancement in marine engineering, more and more new structures are being designed and explored for tidal current energy. There are three different kinds of support structures for tidal current power station mostly in use, which are sea-bed mounted/gravity based system, pile mounted system and floating moored platform. Comparing all of them, the floating mooring system is most suitable for deep water systems and the application of this arrangement is widely usable. In this paper, a semi-submersible and a catamaran as floating platforms for tidal current power stations are studied are compared on the basis of its economics, efficiency of turbine and stability of the station. Based on basic ship theory and using software MAXSURF, the stability of Catamaran tidal current power station is also calculated. It is found that the catamaran design is optimal choice.

New Maps of California to Improve Tsunami Preparedness

NASA Astrophysics Data System (ADS)

Barberopoulou, Aggeliki; Borrero, Jose C.; Uslu, Burak; Kalligeris, Nikos; Goltz, James D.; Wilson, Rick I.; Synolakis, Costas E.

2009-04-01

On 25 April 1992, an M 7.1 earthquake shook the coast of Cape Mendocino near Petrolia, Calif., followed by two large aftershocks (both M ˜ 6.6) the next day. Although no lives were lost in these temblors, 98 people were injured. These earthquakes heavily damaged older structures within this sparsely populated, mountainous region, causing more than US$66 million in losses. Approximately 20 minutes after the first earthquake, tide gauge stations in nearby Crescent City reported a surge—a tsunami with maximum wave heights (from trough to crest) of 1.1 meters. The tsunami hit Crescent City and Eureka at low tide. Fortunately, no damages occurred to city or harbor facilities—had this happened during high tide, it may have been a different story [McCarthy et al., 1993].

DIFMOS - A floating-gate electrically erasable nonvolatile semiconductor memory technology. [Dual Injector Floating-gate MOS

NASA Technical Reports Server (NTRS)

Gosney, W. M.

1977-01-01

Electrically alterable read-only memories (EAROM's) or reprogrammable read-only memories (RPROM's) can be fabricated using a single-level metal-gate p-channel MOS technology with all conventional processing steps. Given the acronym DIFMOS for dual-injector floating-gate MOS, this technology utilizes the floating-gate technique for nonvolatile storage of data. Avalanche injection of hot electrons through gate oxide from a special injector diode in each bit is used to charge the floating gates. A second injector structure included in each bit permits discharge of the floating gate by avalanche injection of holes through gate oxide. The overall design of the DIFMOS bit is dictated by the physical considerations required for each of the avalanche injector types. The end result is a circuit technology which can provide fully decoded bit-erasable EAROM-type circuits using conventional manufacturing techniques.

Numerical experiment on tsunami deposit distribution process by using tsunami sediment transport model in historical tsunami event of megathrust Nankai trough earthquake

NASA Astrophysics Data System (ADS)

Imai, K.; Sugawara, D.; Takahashi, T.

2017-12-01

A large flow caused by tsunami transports sediments from beach and forms tsunami deposits in land and coastal lakes. A tsunami deposit has been found in their undisturbed on coastal lakes especially. Okamura & Matsuoka (2012) found some tsunami deposits in the field survey of coastal lakes facing to the Nankai trough, and tsunami deposits due to the past eight Nankai Trough megathrust earthquakes they identified. The environment in coastal lakes is stably calm and suitable for tsunami deposits preservation compared to other topographical conditions such as plains. Therefore, there is a possibility that the recurrence interval of megathrust earthquakes and tsunamis will be discussed with high resolution. In addition, it has been pointed out that small events that cannot be detected in plains could be separated finely (Sawai, 2012). Various aspects of past tsunami is expected to be elucidated, in consideration of topographical conditions of coastal lakes by using the relationship between the erosion-and-sedimentation process of the lake bottom and the external force of tsunami. In this research, numerical examination based on tsunami sediment transport model (Takahashi et al., 1999) was carried out on the site Ryujin-ike pond of Ohita, Japan where tsunami deposit was identified, and deposit migration analysis was conducted on the tsunami deposit distribution process of historical Nankai Trough earthquakes. Furthermore, examination of tsunami source conditions is possibly investigated by comparison studies of the observed data and the computation of tsunami deposit distribution. It is difficult to clarify details of tsunami source from indistinct information of paleogeographical conditions. However, this result shows that it can be used as a constraint condition of the tsunami source scale by combining tsunami deposit distribution in lakes with computation data.

Determination of the State of Strain of Large Floating Covers Using Unmanned Aerial Vehicle (UAV) Aided Photogrammetry

PubMed Central

Ong, Wern Hann; Chiu, Wing Kong; Kuen, Thomas; Kodikara, Jayantha

2017-01-01

Floating covers used in waste water treatment plants are one of the many structures formed with membrane materials. These structures are usually large and can spread over an area measuring 470 m × 170 m. The aim of this paper is to describe recent work to develop an innovative and effective approach for structural health monitoring (SHM) of such large membrane-like infrastructure. This paper will propose a potentially cost-effective non-contact approach for full-field strain and stress mapping using an unmanned aerial vehicle (UAV) mounted with a digital camera and a global positioning system (GPS) tracker. The aim is to use the images acquired by the UAV to define the geometry of the floating cover using photogrammetry. In this manner, any changes in the geometry of the floating cover due to forces acting beneath resulting from its deployment and usage can be determined. The time-scale for these changes is in terms of weeks and months. The change in the geometry can be implemented as input conditions to a finite element model (FEM) for stress prediction. This will facilitate the determination of the state of distress of the floating cover. This paper investigates the possibility of using data recorded from a UAV to predict the strain level and assess the health of such structures. An investigation was first conducted on a laboratory sized membrane structure instrumented with strain gauges for comparison against strains, which were computed from 3D scans of the membrane geometry. Upon validating the technique in the laboratory, it was applied to a more realistic scenario: an outdoor test membrane structure and capable UAV were constructed to see if the shape of the membrane could be computed. The membrane displacements were then used to calculate the membrane stress and strain, state demonstrating a new way to perform structural health monitoring on membrane structures. PMID:28788081

Determination of the State of Strain of Large Floating Covers Using Unmanned Aerial Vehicle (UAV) Aided Photogrammetry.

PubMed

Ong, Wern Hann; Chiu, Wing Kong; Kuen, Thomas; Kodikara, Jayantha

2017-07-28

Floating covers used in waste water treatment plants are one of the many structures formed with membrane materials. These structures are usually large and can spread over an area measuring 470 m × 170 m. The aim of this paper is to describe recent work to develop an innovative and effective approach for structural health monitoring (SHM) of such large membrane-like infrastructure. This paper will propose a potentially cost-effective non-contact approach for full-field strain and stress mapping using an unmanned aerial vehicle (UAV) mounted with a digital camera and a global positioning system (GPS) tracker. The aim is to use the images acquired by the UAV to define the geometry of the floating cover using photogrammetry. In this manner, any changes in the geometry of the floating cover due to forces acting beneath resulting from its deployment and usage can be determined. The time-scale for these changes is in terms of weeks and months. The change in the geometry can be implemented as input conditions to a finite element model (FEM) for stress prediction. This will facilitate the determination of the state of distress of the floating cover. This paper investigates the possibility of using data recorded from a UAV to predict the strain level and assess the health of such structures. An investigation was first conducted on a laboratory sized membrane structure instrumented with strain gauges for comparison against strains, which were computed from 3D scans of the membrane geometry. Upon validating the technique in the laboratory, it was applied to a more realistic scenario: an outdoor test membrane structure and capable UAV were constructed to see if the shape of the membrane could be computed. The membrane displacements were then used to calculate the membrane stress and strain, state demonstrating a new way to perform structural health monitoring on membrane structures.

Model validation and error estimation of tsunami runup using high resolution data in Sadeng Port, Gunungkidul, Yogyakarta

NASA Astrophysics Data System (ADS)

Basith, Abdul; Prakoso, Yudhono; Kongko, Widjo

2017-07-01

A tsunami model using high resolution geometric data is indispensable in efforts to tsunami mitigation, especially in tsunami prone areas. It is one of the factors that affect the accuracy results of numerical modeling of tsunami. Sadeng Port is a new infrastructure in the Southern Coast of Java which could potentially hit by massive tsunami from seismic gap. This paper discusses validation and error estimation of tsunami model created using high resolution geometric data in Sadeng Port. Tsunami model validation uses the height wave of Tsunami Pangandaran 2006 recorded by Tide Gauge of Sadeng. Tsunami model will be used to accommodate the tsunami numerical modeling involves the parameters of earthquake-tsunami which is derived from the seismic gap. The validation results using t-test (student) shows that the height of the tsunami modeling results and observation in Tide Gauge of Sadeng are considered statistically equal at 95% confidence level and the value of the RMSE and NRMSE are 0.428 m and 22.12%, while the differences of tsunami wave travel time is 12 minutes.

Geodetic Imaging and Tsunami Modeling of the 2017 Coupled Landslide-Tsunami Event in Karrat Fjord, West Greenland.

NASA Astrophysics Data System (ADS)

Barba, M.; Willis, M. J.; Tiampo, K. F.; Lynett, P. J.; Mätzler, E.; Thorsøe, K.; Higman, B. M.; Thompson, J. A.; Morin, P. J.

2017-12-01

We use a combination of geodetic imaging techniques and modelling efforts to examine the June 2017 Karrat Fjord, West Greenland, landslide and tsunami event. Our efforts include analysis of pre-cursor motions extracted from Sentinal SAR interferometry that we improved with high-resolution Digital Surface Models derived from commercial imagery and geo-coded Structure from Motion analyses. We produce well constrained estimates of landslide volume through DSM differencing by improving the ArcticDEM coverage of the region, and provide modeled tsunami run-up estimates at villages around the region, constrained with in-situ observations provided by the Greenlandic authorities. Estimates of run-up at unoccupied coasts are derived using a blend of high resolution imagery and elevation models. We further detail post-failure slope stability for areas of interest around the Karrat Fjord region. Warming trends in the region from model and satellite analysis are combined with optical imagery to ascertain whether the influence of melting permafrost and the formation of small springs on a slight bench on the mountainside that eventually failed can be used as indicators of future events.

Magnitude scale for the Central American tsunamis

NASA Astrophysics Data System (ADS)

Hatori, Tokutaro

1995-09-01

Based on the tsunami data in the Central American region, the regional characteristic of tsunami magnitude scales is discussed in relation to earthquake magnitudes during the period from 1900 to 1993. Tsunami magnitudes on the Imamura-Iida scale of the 1985 Mexico and 1992 Nicaragua tsunamis are determined to be m=2.5, judging from the tsunami height-distance diagram. The magnitude values of the Central American tsunamis are relatively small compared to earthquakes with similar size in other regions. However, there are a few large tsunamis generated by low-frequency earthquakes such as the 1992 Nicaragua earthquake. Inundation heights of these unusual tsunamis are about 10 times higher than those of normal tsunamis for the same earthquake magnitude ( M s =6.9 7.2). The Central American tsunamis having magnitude m>1 have been observed by the Japanese tide stations, but the effect of directivity toward Japan is very small compared to that of the South American tsunamis.

Correlation Equation of Fault Size, Moment Magnitude, and Height of Tsunami Case Study: Historical Tsunami Database in Sulawesi

NASA Astrophysics Data System (ADS)

Julius, Musa, Admiral; Pribadi, Sugeng; Muzli, Muzli

2018-03-01

Sulawesi, one of the biggest island in Indonesia, located on the convergence of two macro plate that is Eurasia and Pacific. NOAA and Novosibirsk Tsunami Laboratory show more than 20 tsunami data recorded in Sulawesi since 1820. Based on this data, determination of correlation between tsunami and earthquake parameter need to be done to proved all event in the past. Complete data of magnitudes, fault sizes and tsunami heights on this study sourced from NOAA and Novosibirsk Tsunami database, completed with Pacific Tsunami Warning Center (PTWC) catalog. This study aims to find correlation between moment magnitude, fault size and tsunami height by simple regression. The step of this research are data collecting, processing, and regression analysis. Result shows moment magnitude, fault size and tsunami heights strongly correlated. This analysis is enough to proved the accuracy of historical tsunami database in Sulawesi on NOAA, Novosibirsk Tsunami Laboratory and PTWC.

Examination of the largest-possible tsunamis (Level 2) generated along the Nankai and Suruga troughs during the past 4000 years based on studies of tsunami deposits from the 2011 Tohoku-oki tsunami

NASA Astrophysics Data System (ADS)

Kitamura, Akihisa

2016-12-01

Japanese historical documents reveal that Mw 8 class earthquakes have occurred every 100-150 years along the Suruga and Nankai troughs since the 684 Hakuho earthquake. These earthquakes have commonly caused large tsunamis with wave heights of up to 10 m in the Japanese coastal area along the Suruga and Nankai troughs. From the perspective of tsunami disaster management, these tsunamis are designated as Level 1 tsunamis and are the basis for the design of coastal protection facilities. A Mw 9.0 earthquake (the 2011 Tohoku-oki earthquake) and a mega-tsunami with wave heights of 10-40 m struck the Pacific coast of the northeastern Japanese mainland on 11 March 2011, and far exceeded pre-disaster predictions of wave height. Based on the lessons learned from the 2011 Tohoku-oki earthquake, the Japanese Government predicted the tsunami heights of the largest-possible tsunami (termed a Level 2 tsunami) that could be generated in the Suruga and Nankai troughs. The difference in wave heights between Level 1 and Level 2 tsunamis exceeds 20 m in some areas, including the southern Izu Peninsula. This study reviews the distribution of prehistorical tsunami deposits and tsunami boulders during the past 4000 years, based on previous studies in the coastal area of Shizuoka Prefecture, Japan. The results show that a tsunami deposit dated at 3400-3300 cal BP can be traced between the Shimizu, Shizuoka and Rokken-gawa lowlands, whereas no geologic evidence related to the corresponding tsunami (the Rokken-gawa-Oya tsunami) was found on the southern Izu Peninsula. Thus, the Rokken-gawa-Oya tsunami is not classified as a Level 2 tsunami.

Submarine slope earthquake-induced instability and associated tsunami generation potential along the Hyblean-Malta Escarpment (offshore eastern Sicily, Italy)

NASA Astrophysics Data System (ADS)

Ausilia Paparo, Maria; Pagnoni, Gianluca; Zaniboni, Filippo; Tinti, Stefano

2016-04-01

The stability analysis of offshore margins is an important step for the assessment of natural hazard: the main challenge is to evaluate the potential slope failures and the consequent occurrence of submarine tsunamigenic landslides to mitigate the potential coastal damage to inhabitants and infrastructures. But the limited geotechnical knowledge of the underwater soil and the controversial scientific interpretation of the tectonic units make it often difficult to carry out this type of analysis reliably. We select the Hyblean-Malta Escarpment (HME), the main active geological structure offshore eastern Sicily, because the amount of data from historical chronicles, the records about strong earthquakes and tsunami, and the numerous geological offshore surveys carried out in recent years make the region an excellent scenario to evaluate slope failures, mass movements triggered by earthquakes and the consequent tsunamis. We choose several profiles along the HME and analyse their equilibrium conditions using the Minimun Lithostatic Deviation (MLD) method (Tinti and Manucci, 2006, 2008; Paparo et al. 2013), that is based on the limit-equilibrium theory. Considering the morphological and geotechnical features of the offshore slopes, we prove that large-earthquake shaking may lead some zones of the HME to instability, we evaluate the expected volumes involved in sliding and compute the associated landslide-tsunami through numerical tsunami simulations. This work was carried out in the frame of the EU Project called ASTARTE - Assessment, STrategy And Risk Reduction for Tsunamis in Europe (Grant 603839, 7th FP, ENV.2013.6.4-3).

Multiple Solutions of Real-time Tsunami Forecasting Using Short-term Inundation Forecasting for Tsunamis Tool

NASA Astrophysics Data System (ADS)

Gica, E.

2016-12-01

The Short-term Inundation Forecasting for Tsunamis (SIFT) tool, developed by NOAA Center for Tsunami Research (NCTR) at the Pacific Marine Environmental Laboratory (PMEL), is used in forecast operations at the Tsunami Warning Centers in Alaska and Hawaii. The SIFT tool relies on a pre-computed tsunami propagation database, real-time DART buoy data, and an inversion algorithm to define the tsunami source. The tsunami propagation database is composed of 50×100km unit sources, simulated basin-wide for at least 24 hours. Different combinations of unit sources, DART buoys, and length of real-time DART buoy data can generate a wide range of results within the defined tsunami source. For an inexperienced SIFT user, the primary challenge is to determine which solution, among multiple solutions for a single tsunami event, would provide the best forecast in real time. This study investigates how the use of different tsunami sources affects simulated tsunamis at tide gauge locations. Using the tide gauge at Hilo, Hawaii, a total of 50 possible solutions for the 2011 Tohoku tsunami are considered. Maximum tsunami wave amplitude and root mean square error results are used to compare tide gauge data and the simulated tsunami time series. Results of this study will facilitate SIFT users' efforts to determine if the simulated tide gauge tsunami time series from a specific tsunami source solution would be within the range of possible solutions. This study will serve as the basis for investigating more historical tsunami events and tide gauge locations.

Compound floating pivot micromechanisms

DOEpatents

Garcia, Ernest J.

2001-04-24

A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

Tsunami.gov: NOAA's Tsunami Information Portal

NASA Astrophysics Data System (ADS)

Shiro, B.; Carrick, J.; Hellman, S. B.; Bernard, M.; Dildine, W. P.

2014-12-01

We present the new Tsunami.gov website, which delivers a single authoritative source of tsunami information for the public and emergency management communities. The site efficiently merges information from NOAA's Tsunami Warning Centers (TWC's) by way of a comprehensive XML feed called Tsunami Event XML (TEX). The resulting unified view allows users to quickly see the latest tsunami alert status in geographic context without having to understand complex TWC areas of responsibility. The new site provides for the creation of a wide range of products beyond the traditional ASCII-based tsunami messages. The publication of modern formats such as Common Alerting Protocol (CAP) can drive geographically aware emergency alert systems like FEMA's Integrated Public Alert and Warning System (IPAWS). Supported are other popular information delivery systems, including email, text messaging, and social media updates. The Tsunami.gov portal allows NOAA staff to easily edit content and provides the facility for users to customize their viewing experience. In addition to access by the public, emergency managers and government officials may be offered the capability to log into the portal for special access rights to decision-making and administrative resources relevant to their respective tsunami warning systems. The site follows modern HTML5 responsive design practices for optimized use on mobile as well as non-mobile platforms. It meets all federal security and accessibility standards. Moving forward, we hope to expand Tsunami.gov to encompass tsunami-related content currently offered on separate websites, including the NOAA Tsunami Website, National Tsunami Hazard Mitigation Program, NOAA Center for Tsunami Research, National Geophysical Data Center's Tsunami Database, and National Data Buoy Center's DART Program. This project is part of the larger Tsunami Information Technology Modernization Project, which is consolidating the software architectures of NOAA's existing TWC's into a single system. We welcome your feedback to help Tsunami.gov become an effective public resource for tsunami information and a medium to enable better global tsunami warning coordination.

Introduction to "Tsunamis in the Pacific Ocean: 2011-2012"

NASA Astrophysics Data System (ADS)

Rabinovich, Alexander B.; Borrero, Jose C.; Fritz, Hermann M.

2014-12-01

With this volume of the Pure and Applied Geophysics (PAGEOPH) topical issue "Tsunamis in the Pacific Ocean: 2011-2012", we are pleased to present 21 new papers discussing tsunami events occurring in this two-year span. Owing to the profound impact resulting from the unique crossover of a natural and nuclear disaster, research into the 11 March 2011 Tohoku, Japan earthquake and tsunami continues; here we present 12 papers related to this event. Three papers report on detailed field survey results and updated analyses of the wave dynamics based on these surveys. Two papers explore the effects of the Tohoku tsunami on the coast of Russia. Three papers discuss the tsunami source mechanism, and four papers deal with tsunami hydrodynamics in the far field or over the wider Pacific basin. In addition, a series of five papers presents studies of four new tsunami and earthquake events occurring over this time period. This includes tsunamis in El Salvador, the Philippines, Japan and the west coast of British Columbia, Canada. Finally, we present four new papers on tsunami science, including discussions on tsunami event duration, tsunami wave amplitude, tsunami energy and tsunami recurrence.

Seismogeodetic monitoring techniques for tsunami and earthquake early warning and rapid assessment of structural damage

NASA Astrophysics Data System (ADS)

Haase, J. S.; Bock, Y.; Saunders, J. K.; Goldberg, D.; Restrepo, J. I.

2016-12-01

As part of an effort to promote the use of NASA-sponsored Earth science information for disaster risk reduction, real-time high-rate seismogeodetic data are being incorporated into early warning and structural monitoring systems. Seismogeodesy combines seismic acceleration and GPS displacement measurements using a tightly-coupled Kalman filter to provide absolute estimates of seismic acceleration, velocity and displacement. Traditionally, the monitoring of earthquakes and tsunamis has been based on seismic networks for estimating earthquake magnitude and slip, and tide gauges and deep-ocean buoys for direct measurement of tsunami waves. Real-time seismogeodetic observations at subduction zones allow for more robust and rapid magnitude and slip estimation that increase warning time in the near-source region. A NASA-funded effort to utilize GPS and seismogeodesy in NOAA's Tsunami Warning Centers in Alaska and Hawaii integrates new modules for picking, locating, and estimating magnitudes and moment tensors for earthquakes into the USGS earthworm environment at the TWCs. In a related project, NASA supports the transition of this research to seismogeodetic tools for disaster preparedness, specifically by implementing GPS and low-cost MEMS accelerometers for structural monitoring in partnership with earthquake engineers. Real-time high-rate seismogeodetic structural monitoring has been implemented on two structures. The first is a parking garage at the Autonomous University of Baja California Faculty of Medicine in Mexicali, not far from the rupture of the 2011 Mw 7.2 El Mayor Cucapah earthquake enabled through a UCMexus collaboration. The second is the 8-story Geisel Library at University of California, San Diego (UCSD). The system has also been installed for several proof-of-concept experiments at the UCSD Network for Earthquake Engineering Simulation (NEES) Large High Performance Outdoor Shake Table. We present MEMS-based seismogeodetic observations from the 10 June 2016 Mw 5.2 Borrego Springs earthquake of strong ground motions in near field close to the San Jacinto fault, as well as observations that show the response of the 3 story parking garage. The occurrence of this recent earthquake provided a useful demonstration of structural monitoring applications with seismogeodesy.

PS3 CELL Development for Scientific Computation and Research

NASA Astrophysics Data System (ADS)

Christiansen, M.; Sevre, E.; Wang, S. M.; Yuen, D. A.; Liu, S.; Lyness, M. D.; Broten, M.

2007-12-01

The Cell processor is one of the most powerful processors on the market, and researchers in the earth sciences may find its parallel architecture to be very useful. A cell processor, with 7 cores, can easily be obtained for experimentation by purchasing a PlayStation 3 (PS3) and installing linux and the IBM SDK. Each core of the PS3 is capable of 25 GFLOPS giving a potential limit of 150 GFLOPS when using all 6 SPUs (synergistic processing units) by using vectorized algorithms. We have used the Cell's computational power to create a program which takes simulated tsunami datasets, parses them, and returns a colorized height field image using ray casting techniques. As expected, the time required to create an image is inversely proportional to the number of SPUs used. We believe that this trend will continue when multiple PS3s are chained using OpenMP functionality and are in the process of researching this. By using the Cell to visualize tsunami data, we have found that its greatest feature is its power. This fact entwines well with the needs of the scientific community where the limiting factor is time. Any algorithm, such as the heat equation, that can be subdivided into multiple parts can take advantage of the PS3 Cell's ability to split the computations across the 6 SPUs reducing required run time by one sixth. Further vectorization of the code can allow for 4 simultanious floating point operations by using the SIMD (single instruction multiple data) capabilities of the SPU increasing efficiency 24 times.

A 2D-3D strategy for resolving tsunami-generated debris flow in urban environments

NASA Astrophysics Data System (ADS)

Birjukovs Canelas, Ricardo; Conde, Daniel; Garcia-Feal, Orlando; João Telhado, Maria; Ferreira, Rui M. L.

2017-04-01

The incorporation of solids, either sediment from the natural environment or remains from buildings or infrastructures is a relevant feature of tsunami run-up in urban environments, greatly increasing the destructive potential of tsunami propagation. Two-dimensional (2D) models have been used to assess the propagation of the bore, even in dense urban fronts. Computational advances are introduced in this work, namely a fully lagrangian, 3D description of the fluid-solid flow, coupled with a high performance meshless implementation capable of dealing with large domains and fine discretizations. A Smoothed Particle Hydrodynamics (SPH) Navier-Stokes discretization and a Distributed Contact Discrete Element Method (DCDEM) description of solid-solid interactions provide a state-of the-art fluid-solid flow description. Together with support for arbitrary geometries, centimetre scale resolution simulations of a city section in Lisbon downtown are presented. 2D results are used as boundary conditions for the 3D model, characterizing the incoming wave as it approaches the coast. It is shown that the incoming bore is able to mobilize and incorporate standing vehicles and other urban hardware. Such fully featured simulation provides explicit description of the interactions among fluid, floating debris (vehicles and urban furniture), the buildings and the pavement. The proposed model presents both an innovative research tool for the study of these flows and a powerful and robust approach to study, design and test mitigation solutions at the local scale. At the same time, due to the high time and space resolution of these methodologies, new questions are raised: scenario-building and initial configurations play a crucial role but they do not univocally determine the final configuration of the simulation, as the solution of the Navier-Stokes equations for high Reynolds numbers possesses a high number of degrees of freedom. This calls for conducting the simulations in a statistical framework, involving both initial conditions generation and interpretation of results, which is only attainable under very high standards of computational efficiency. This research as partially supported by Portuguese and European funds, within programs COMPETE2020 and PORL-FEDER, through project PTDC/ECM-HID/6387/2014 granted by the National Foundation for Science and Technology (FCT).

The AD 365 earthquake: high resolution tsunami inundation for Crete and full scale simulation exercise

NASA Astrophysics Data System (ADS)

Kalligeris, N.; Flouri, E.; Okal, E.; Synolakis, C.

2012-04-01

In the eastern Mediterranean, historical and archaeological records document major earthquake and tsunami events in the past 2000 year (Ambraseys and Synolakis, 2010). The 1200km long Hellenic Arc has allegedly caused the strongest reported earthquakes and tsunamis in the region. Among them, the AD 365 and AD 1303 tsunamis have been extensively documented. They are likely due to ruptures of the Central and Eastern segments of the Hellenic Arc, respectively. Both events had widespread impact due to ground shaking, and e triggered tsunami waves that reportedly affected the entire eastern Mediterranean. The seismic mechanism of the AD 365 earthquake, located in western Crete, has been recently assigned a magnitude ranging from 8.3 to 8.5 by Shaw et al., (2008), using historical, sedimentological, geomorphic and archaeological evidence. Shaw et al (2008) have inferred that such large earthquakes occur in the Arc every 600 to 800 years, with the last known the AD 1303 event. We report on a full-scale simulation exercise that took place in Crete on 24-25 October 2011, based on a scenario sufficiently large to overwhelm the emergency response capability of Greece and necessitating the invocation of the Monitoring and Information Centre (MIC) of the EU and triggering help from other nations . A repeat of the 365 A.D. earthquake would likely overwhelm the civil defense capacities of Greece. Immediately following the rupture initiation it will cause substantial damage even to well-designed reinforced concrete structures in Crete. Minutes after initiation, the tsunami generated by the rapid displacement of the ocean floor would strike nearby coastal areas, inundating great distances in areas of low topography. The objective of the exercise was to help managers plan search and rescue operations, identify measures useful for inclusion in the coastal resiliency index of Ewing and Synolakis (2011). For the scenario design, the tsunami hazard for the AD 365 event was assessed for the biggest island lying in proximity of the Hellenic Arc, namely Crete. High resolution tsunami inundation modelling was performed for Heraklion and Chania. We use MOST, a non-linear finite difference hydrodynamic model thoroughly benchmarked, coupled with accurate bathymetry and topography data. Also, we used empirical attenuation relationships to estimate the effects of ground shaking on infrastructure complementing the scenario design. Tsunami inundation and ground acceleration maps are presented for the study areas, providing valuable information for earthquake and tsunami hazard.

Sedimentology of Coastal Deposits in the Seychelles Islands—Evidence of the Indian Ocean Tsunami 2004

NASA Astrophysics Data System (ADS)

Nentwig, Vanessa; Bahlburg, Heinrich; Monthy, Devis

2015-03-01

The Seychelles, an archipelago in the Indian Ocean at a distance of 4,500-5,000 km from the west coast of Sumatra, were severely affected by the December 26, 2004 tsunami with wave heights up to 4 m. Since the tsunami history of small islands often remains unclear due to a young historical record, it is important to study the geological traces of high energy events preserved along their coasts. We conducted a survey of the impact of the 2004 Indian Ocean tsunami on the inner Seychelles islands. In detail we studied onshore tsunami deposits in the mangrove forest at Old Turtle Pond in the Curieuse Marine National Park on the east coast of Curieuse Island. It is thus protected from anthropogenic interference. Towards the sea it was shielded until the tsunami in 2004 by a 500 m long and 1.5 m high causeway which was set up in 1909 as a sediment trap and assuring a low energetic hydrodynamic environment for the protection of the mangroves. The causeway was destroyed by the 2004 Indian Ocean Tsunami. The tsunami caused a change of habitat by the sedimentation of sand lobes in the mangrove forest. The dark organic rich mangrove soil (1.9 Φ) was covered by bimodal fine to medium carbonate sand (1.7-2.2 Φ) containing coarser carbonate shell fragments and debris. Intertidal sediments and the mangrove soil acted as sources of the lobe deposits. The sand sheet deposited by the tsunami is organized into different lobes. They extend landwards to different inundation distances as a function of the morphology of the onshore area. The maximum extent of 180 m from the shoreline indicates the minimum inundation distance to the tsunami. The top parts of the sand lobes cover the pneumatophores of the mangroves. There is no landward fining trend along the sand lobes and normal grading of the deposits is rare, occurring only in 1 of 7 sites. The sand lobe deposits also lack sedimentary structures. On the surface of the sand lobes numerous mostly fragmented shells of bivalves and molluscs were distributed up to 150 m from the coastline. Intact bivalve shells were mostly found positioned with the convex side upwards. On small ledges of a granitic body at 130-150 m from the shore mostly fragmented and gravel sized shells were deposited at different elevations up to 4 m above sea level. This implies a run up height of at least 4 m above sea level up to 150 m from the present shoreline.

Tsunami forecast by joint inversion of real-time tsunami waveforms and seismic of GPS data: application to the Tohoku 2011 tsunami

USGS Publications Warehouse

Yong, Wei; Newman, Andrew V.; Hayes, Gavin P.; Titov, Vasily V.; Tang, Liujuan

2014-01-01

Correctly characterizing tsunami source generation is the most critical component of modern tsunami forecasting. Although difficult to quantify directly, a tsunami source can be modeled via different methods using a variety of measurements from deep-ocean tsunameters, seismometers, GPS, and other advanced instruments, some of which in or near real time. Here we assess the performance of different source models for the destructive 11 March 2011 Japan tsunami using model–data comparison for the generation, propagation, and inundation in the near field of Japan. This comparative study of tsunami source models addresses the advantages and limitations of different real-time measurements with potential use in early tsunami warning in the near and far field. The study highlights the critical role of deep-ocean tsunami measurements and rapid validation of the approximate tsunami source for high-quality forecasting. We show that these tsunami measurements are compatible with other real-time geodetic data, and may provide more insightful understanding of tsunami generation from earthquakes, as well as from nonseismic processes such as submarine landslide failures.

Tsunami Focusing and Leading Amplitude

NASA Astrophysics Data System (ADS)

Kanoglu, U.

2016-12-01

Tsunamis transform substantially through spatial and temporal spreading from their source region. This substantial spreading might result unique maximum tsunami wave heights which might be attributed to the source configuration, directivity, the waveguide structures of mid-ocean ridges and continental shelves, focusing and defocusing through submarine seamounts, random focusing due to small changes in bathymetry, dispersion, and, most likely, combination of some of these effects. In terms of the maximum tsunami wave height, after Okal and Synolakis (2016 Geophys. J. Int. 204, 719-735), it is clear that dispersion would be one of the reasons to drive the leading wave amplitude in a tsunami wave train. Okal and Synolakis (2016), referring to this phenomenon as sequencing -later waves in the train becoming higher than the leading one, considered Hammack's (1972, Ph.D. Dissertation, Calif. Inst. Tech., 261 pp) formalism, in addition to LeMéhauté and Wang's (1995 Water waves generated by underwater explosion, World Scientific, 367 pp), to evaluate linear dispersive tsunami propagation from a circular plug uplifted on an ocean of constant depth. They identified transition distance, as the second wave being larger, performing parametric study for the radius of the plug and the depth of the ocean. Here, we extend Okal and Synolakis' (2016) analysis to an initial wave field with a finite crest length and, in addition, to a most common tsunami initial wave form of N-wave (Tadepalli and Synolakis, 1994 Proc. R. Soc. A: Math. Phys. Eng. Sci. 445, 99-112). First, we investigate the focusing feature in the leading-depression side, which enhance tsunami wave height as presented by Kanoglu et al. (2013 Proc. R. Soc. A: Math. Phys. Eng. Sci. 469, 20130015). We then discuss the results in terms of leading wave amplitude presenting a parametric study and identify a simple relation for the transition distance. The solution presented here could be used to better analyze dispersive characteristics of shallow water-wave numerical models and for benchmarking, in addition to the benchmark problems in Synolakis et al. (2008 Pure Appl. Geophys. 165(11-12), 2197-2228). This study received funding from project ASTARTE-Assessment Strategy and Risk Reduction for Tsunamis in Europe, a collaborative project Grant 603839, FP7-ENV2013 6.4-3.

Evaluation of Refuge Life Risk using Geographical and Social Grid-Models with Satellite-Based House Ratio and Flood Depth by Tsunami Simulation

NASA Astrophysics Data System (ADS)

Kaneko, D.; Hosoyamada, T.

2017-12-01

The authors have developed social and geographical models for evaluating and applying life risk to the Kamakura coast near the south-western part of the metropolitan areas of Tokyo. The coastline close to the seismic center of the South Kanto earthquake is in the riskiest belt in the metropolitan area with a high possibility of house collapse and tsunami run-up. Kamakura is an important historical city, visited by many tourists who are not familiar with seismic dangers. There is a high probability of loss of human life during an evacuation of the city during tsunami waves. To evaluate the distribution of life risk characteristics in the area, models for citizens and sightseers are developed that includes social data such as population density, wooden-house ratio, and geographical evacuation distance and tsunami-flooding depth. The population of Kamakura City is 174,050 and the risk of tsunami evacuation is high in the area from the southern part of Kamakura Station to Zaimokuza block, where the population is approximately 15,310 people. There are about 26,000 tourists visiting this area on weekdays and about 100,000 sightseers visiting the area on Saturdays and Sundays. On weekdays the population per mesh will increase by half of the 2,000 inhabitants. On Saturdays and Sundays the population density will be 4 thousand who will double those of the inhabitants. A disaster prevention hill is proposed as a tsunami countermeasure on the coast of Kamakura City. The hill is covered by pine forest with a high-standard road, evacuation center, and sightseeing parking lots embedded in the hilly bank. In normal times, tourists and citizens use this area as a seaside pine park. Long concrete box structures strengthen the hill inside the mound, which has two levels, the lower equipped with high-standard-width roads on the ground level. The parking areas will resolve daily traffic congestion issues along the Kamakura main streets. The evaluation of over-flooding tsunamis and evacuation measures against life risk have been created using satellite land-cover classification data in the city. The two models using tsunami-flooding simulation have been used to design the disaster prevention hill. The results obtained contribute to preparing the society for disaster prevention measures or reconstruction after tsunami disasters.

Local variation of inundation, sedimentary characteristics, and mineral assemblages of the 2011 Tohoku-oki tsunami on the Misawa coast, Aomori, Japan

NASA Astrophysics Data System (ADS)

Nakamura, Yugo; Nishimura, Yuichi; Putra, Purna Sulastya

2012-12-01

The 2011 Tohoku-oki tsunami caused severe damage to the coastal regions of eastern Japan and left a sediment veneer over affected areas. We discuss differences in depositional characteristics of the 2011 Tohoku-oki tsunami from the viewpoint of the sediment source, coastal topography and flow height. The study area on the Misawa coast, northern Tohoku, includes a 20 km long coastline with sandy beaches, coastal dunes and a gently sloping lowland. This landscape assemblage provides an opportunity to examine the effects of topography on the characteristics of the tsunami deposit. During field surveys conducted from April 10 to May 2, 2011, we described the thickness, facies, and structure of the tsunami deposit. We also collected sand samples at approximately 20 m intervals along 13 shore-perpendicular transects extending up to 550 m inland, for grain size and mineral assemblage analysis. The tsunami flow height was estimated by measuring the elevation of debris found in trees, broken tree limbs, or water marks on buildings. The nature of the coastal lowland affected the flow height and inundation distance. In the southern part of the study area, where there is a narrow, 100 m wide low-lying coastal strip, the run-up height reached 10 m on the landward terrace slopes. To the north, the maximum inundation reached 550 m with a run-up height of 3.2 m on the wider, low-lying coastal topography. The average flow height was 4-5 m. The tsunami eroded coastal dunes and formed small scarps along the coast. Immediately landward of the coastal dunes the tsunami deposit was more than 20 cm thick, but thinned markedly inland from this point. Close to the dunes the deposit was composed largely of medium sand (1-2 Φ) with planar and parallel bedding, but with no apparent upward fining or coarsening. The grain size was similar to that of the coastal dune and we infer that the dunes were the local source material for the tsunami deposit at this point. The mineral assemblage of the tsunami deposit was dominated by orthopyroxene and clinopyroxene and was also similar to the dune and beach sand. At sites more than half the inundation distance inland, the thinner tsunami deposit consisted mainly of fine sand (2.375 Φ) with some upward fining. The difference in grain size and sedimentary characteristics was probably caused by differences in sediment transportation and depositional processes. We infer that the well-sorted, finer sediments were deposited out of suspension, whereas the relatively coarse sands were laid down from traction flows. The depositional characteristics of the 2011 Tohoku-oki tsunami deposit appeared to have been affected mainly by the coastal topography and the extent of erosion at any one point, as opposed to flow height.

Documentation for the Southeast Asia seismic hazard maps

USGS Publications Warehouse

Petersen, Mark; Harmsen, Stephen; Mueller, Charles; Haller, Kathleen; Dewey, James; Luco, Nicolas; Crone, Anthony; Lidke, David; Rukstales, Kenneth

2007-01-01

The U.S. Geological Survey (USGS) Southeast Asia Seismic Hazard Project originated in response to the 26 December 2004 Sumatra earthquake (M9.2) and the resulting tsunami that caused significant casualties and economic losses in Indonesia, Thailand, Malaysia, India, Sri Lanka, and the Maldives. During the course of this project, several great earthquakes ruptured subduction zones along the southern coast of Indonesia (fig. 1) causing additional structural damage and casualties in nearby communities. Future structural damage and societal losses from large earthquakes can be mitigated by providing an advance warning of tsunamis and introducing seismic hazard provisions in building codes that allow buildings and structures to withstand strong ground shaking associated with anticipated earthquakes. The Southeast Asia Seismic Hazard Project was funded through a United States Agency for International Development (USAID)—Indian Ocean Tsunami Warning System to develop seismic hazard maps that would assist engineers in designing buildings that will resist earthquake strong ground shaking. An important objective of this project was to discuss regional hazard issues with building code officials, scientists, and engineers in Thailand, Malaysia, and Indonesia. The code communities have been receptive to these discussions and are considering updating the Thailand and Indonesia building codes to incorporate new information (for example, see notes from Professor Panitan Lukkunaprasit, Chulalongkorn University in Appendix A).

Analysis of geodetic interseismic coupling models to estimate tsunami inundation and runup: a study case of Maule seismic gap, Chile

NASA Astrophysics Data System (ADS)

González-Carrasco, J. F.; Gonzalez, G.; Aránguiz, R.; Catalan, P. A.; Cienfuegos, R.; Urrutia, A.; Shrivastava, M. N.; Yagi, Y.; Moreno, M.

2015-12-01

Tsunami inundation maps are a powerful tool to design evacuation plans of coastal communities, additionally can be used as a guide to territorial planning and assessment of structural damages in port facilities and critical infrastructure (Borrero et al., 2003; Barberopoulou et al., 2011; Power et al., 2012; Mueller et al., 2015). The accuracy of inundation estimation is highly correlated with tsunami initial conditions, e.g. seafloor vertical deformation, displaced water volume and potential energy (Bolshakova et al., 2011). Usually, the initial conditions are estimated using homogeneous rupture models based in historical worst-case scenario. However tsunamigenic events occurred in central Chilean continental margin showed a heterogeneous slip distribution of source with patches of high slip, correlated with fully-coupled interseismic zones (Moreno et al., 2012). The main objective of this work is to evaluate the predictive capacity of interseismic coupling models based on geodetic data comparing them with homogeneous fault slip model constructed using scaling laws (Blaser et al., 2010) to estimate inundation and runup in coastal areas. To test our hypothesis we select a seismic gap of Maule, where occurred the last large tsunamigenic earthquake in the chilean subduction zone, using the interseismic coupling models (ISC) proposed by Moreno et al., 2011 and Métois et al., 2013. We generate a slip deficit distribution to build a tsunami source supported by geological information such as slab depth (Hayes et al., 2012), strike, rake and dip (Dziewonski et al., 1981; Ekström et al., 2012) to model tsunami generation, propagation and shoreline impact using Neowave 2D (Yamazaki et al., 2009). We compare the tsunami scenario of Mw 8.8, Maule based in coseismic slip distribution proposed by Moreno et al., 2012 with homogeneous and heterogeneous models to identify the accuracy of our results with sea level time series and regional runup data (Figure 1). The estimation of tsunami source using ISC model can be useful to improve the analysis of tsunami threat, based in more realistic slip distribution.

Early-Ming Era tsunami destruction along the Northern Coast of Aceh, Indonesia: New evidence from Archeology

NASA Astrophysics Data System (ADS)

Sieh, K.; Daly, P.; McKinnon, E. E.; Tai, Y. S.; Feener, R. M.; Ishmail, N.

2017-12-01

Our colleagues and we have reconstructed partial earthquake and tsunami histories along the coast of Aceh, Sumatra. Chlieh et al (2006) documented and modeled deformation of offshore islands associated with the 2004 rupture. Meltzner et al (2010) found coral evidence of uplifts in 1394±2 and 1450±3 CE. Sieh et al. (2015) documented associated tsunami that destroyed a structure built in 1366±3 CE, 40 km east of Banda Aceh at Lamreh. Since 2015, our landscape archaeology survey of 43 coastal villages over a 40-km reach of the coast has revealed 995 archaeological sites ranging from 10th century to present and containing over 5,000 carved gravestones and 50,000 ceramic sherds. The distribution of ceramic material suggests 7 discrete areas of cultural activity before the 1394 tsunami. Six of these appear to be villages that used imported ceramics and have been populated since the 10th century. However, detailed analysis indicates a clear reduction in activity between 1360 and 1450 CE. This suggests that one or both of the 1394 and 1450 tsunami disrupted the villages. The distribution of post-1500 CE ceramic material shows a gradual repopulation of pre-tsunami sites and a significant expansion of activity starting at the end of the 16th Century, for all areas except Lamreh. Only at on the elevated Lambaro highlands, above modern Lamreh, does material conclusively date between the 1394 and 1450 CE tsunamis. This historic trading site of "Lambri" contains large quantities of ceramics ranging from the early 11th century until the early 16th century, including precisely dated early-Ming (1403-1425 CE) material, some of which is distinctive imperial trade ceramics. We suspect that after the 1394 tsunami destroyed the other coastal settlements, the relatively safe highlands of Lambri were the only areas of the coast utilized for at least 50 years. After about 1450 CE, however, these highlands were abandoned, while the low-lying coastal communities began once again to flourish. For more details, please visit our poster.

Source Rupture Models and Tsunami Simulations of Destructive October 28, 2012 Queen Charlotte Islands, British Columbia (Mw: 7.8) and September 16, 2015 Illapel, Chile (Mw: 8.3) Earthquakes

NASA Astrophysics Data System (ADS)

Taymaz, Tuncay; Yolsal-Çevikbilen, Seda; Ulutaş, Ergin

2016-04-01

The finite-fault source rupture models and numerical simulations of tsunami waves generated by 28 October 2012 Queen Charlotte Islands (Mw: 7.8), and 16 September 2015 Illapel-Chile (Mw: 8.3) earthquakes are presented. These subduction zone earthquakes have reverse faulting mechanisms with small amount of strike-slip components which clearly reflect the characteristics of convergence zones. The finite-fault slip models of the 2012 Queen Charlotte and 2015 Chile earthquakes are estimated from a back-projection method that uses teleseismic P- waveforms to integrate the direct P-phase with reflected phases from structural discontinuities near the source. Non-uniform rupture models of the fault plane, which are obtained from the finite fault modeling, are used in order to describe the vertical displacement on seabed. In general, the vertical displacement of water surface was considered to be the same as ocean bottom displacement, and it is assumed to be responsible for the initial water surface deformation gives rise to occurrence of tsunami waves. In this study, it was calculated by using the elastic dislocation algorithm. The results of numerical tsunami simulations are compared with tide gauges and Deep-ocean Assessment and Reporting of Tsunami (DART) buoy records. De-tiding, de-trending, low-pass and high-pass filters were applied to detect tsunami waves in deep ocean sensors and tide gauge records. As an example, the observed records and results of simulations showed that the 2012 Queen Charlotte Islands earthquake generated about 1 meter tsunami-waves in Maui and Hilo (Hawaii), 5 hours and 30 minutes after the earthquake. Furthermore, the calculated amplitudes and time series of the tsunami waves of the recent 2015 Illapel (Chile) earthquake are exhibiting good agreement with the records of tide and DART gauges except at stations Valparaiso and Pichidangui (Chile). This project is supported by The Scientific and Technological Research Council of Turkey (TUBITAK Project No: CAYDAG-114Y066).

Assessment of Efficiency and Performance in Tsunami Numerical Modeling with GPU

NASA Astrophysics Data System (ADS)

Yalciner, Bora; Zaytsev, Andrey

2017-04-01

Non-linear shallow water equations (NSWE) are used to solve the propagation and coastal amplification of long waves and tsunamis. Leap Frog scheme of finite difference technique is one of the satisfactory numerical methods which is widely used in these problems. Tsunami numerical models are necessary for not only academic but also operational purposes which need faster and accurate solutions. Recent developments in information technology provide considerably faster numerical solutions in this respect and are becoming one of the crucial requirements. Tsunami numerical code NAMI DANCE uses finite difference numerical method to solve linear and non-linear forms of shallow water equations for long wave problems, specifically for tsunamis. In this study, the new code is structured for Graphical Processing Unit (GPU) using CUDA API. The new code is applied to different (analytical, experimental and field) benchmark problems of tsunamis for tests. One of those applications is 2011 Great East Japan tsunami which was instrumentally recorded on various types of gauges including tide and wave gauges and offshore GPS buoys cabled Ocean Bottom Pressure (OBP) gauges and DART buoys. The accuracy of the results are compared with the measurements and fairly well agreements are obtained. The efficiency and performance of the code is also compared with the version using multi-core Central Processing Unit (CPU). Dependence of simulation speed with GPU on linear or non-linear solutions is also investigated. One of the results is that the simulation speed is increased up to 75 times comparing to the process time in the computer using single 4/8 thread multi-core CPU. The results are presented with comparisons and discussions. Furthermore how multi-dimensional finite difference problems fits towards GPU architecture is also discussed. The research leading to this study has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement No: 603839 (Project ASTARTE-Assessment, Strategy and Risk Reduction for Tsunamis in Europe). PARI, Japan and NOAA, USA are acknowledged for the data of the measurements. Prof. Ahmet C. Yalciner is also acknowledged for his long term and sustained support to the authors.

Tsunami Forecast Progress Five Years After Indonesian Disaster

NASA Astrophysics Data System (ADS)

Titov, Vasily V.; Bernard, Eddie N.; Weinstein, Stuart A.; Kanoglu, Utku; Synolakis, Costas E.

2010-05-01

Almost five years after the 26 December 2004 Indian Ocean tragedy, tsunami warnings are finally benefiting from decades of research toward effective model-based forecasts. Since the 2004 tsunami, two seminal advances have been (i) deep-ocean tsunami measurements with tsunameters and (ii) their use in accurately forecasting tsunamis after the tsunami has been generated. Using direct measurements of deep-ocean tsunami heights, assimilated into numerical models for specific locations, greatly improves the real-time forecast accuracy over earthquake-derived magnitude estimates of tsunami impact. Since 2003, this method has been used to forecast tsunamis at specific harbors for different events in the Pacific and Indian Oceans. Recent tsunamis illustrated how this technology is being adopted in global tsunami warning operations. The U.S. forecasting system was used by both research and operations to evaluate the tsunami hazard. Tests demonstrated the effectiveness of operational tsunami forecasting using real-time deep-ocean data assimilated into forecast models. Several examples also showed potential of distributed forecast tools. With IOC and USAID funding, NOAA researchers at PMEL developed the Community Model Interface for Tsunami (ComMIT) tool and distributed it through extensive capacity-building sessions in the Indian Ocean. Over hundred scientists have been trained in tsunami inundation mapping, leading to the first generation of inundation models for many Indian Ocean shorelines. These same inundation models can also be used for real-time tsunami forecasts as was demonstrated during several events. Contact Information Vasily V. Titov, Seattle, Washington, USA, 98115

Sandy signs of a tsunami's onshore depth and speed

USGS Publications Warehouse

Huntington, K.; Bourgeois, J.; Gelfenbaum, G.; Lynett, P.; Jaffe, B.; Yeh, H.; Weiss, R.

2007-01-01

Tsunamis rank among the most devastating and unpredictable natural hazards to affect coastal areas. Just 3 years ago, in December 2004, the Indian Ocean tsunami caused more than 225,000 deaths. Like many extreme events, however, destructive tsunamis strike rarely enough that written records span too little time to quantify tsunami hazard and risk. Tsunami deposits preserved in the geologic record have been used to extend the record of tsunami occurrence but not the magnitude of past events. To quantify tsunami hazard further, we asked the following question: Can ancient deposits also provide guidance on the expectable water depths and speeds for future tsunamis?

Glider Observations of Upper Ocean Structure in the Bay of Bengal

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Glider Observations of Upper Ocean Structure in the Bay...using gliders and floats • Improve glider technology to overcome fresh, buoyant surface layers • Establish a new technology to observe turbulence...with profiling floats APPROACH We use two approaches to observe the upper ocean in the BoB. First, we deploy Spray underwater gliders to resolve

Issues of tsunami hazard maps revealed by the 2011 Tohoku tsunami

NASA Astrophysics Data System (ADS)

Sugimoto, M.

2013-12-01

Tsunami scientists are imposed responsibilities of selection for people's tsunami evacuation place after the 2011 Tohoku Tsunami in Japan. A lot of matured people died out of tsunami hazard zone based on tsunami hazard map though students made a miracle by evacuation on their own judgment in Kamaishi city. Tsunami hazard maps were based on numerical model smaller than actual magnitude 9. How can we bridge the gap between hazard map and future disasters? We have to discuss about using tsunami numerical model better enough to contribute tsunami hazard map. How do we have to improve tsunami hazard map? Tsunami hazard map should be revised included possibility of upthrust or downthrust after earthquakes and social information. Ground sank 1.14m below sea level in Ayukawa town, Tohoku. Ministry of Land, Infrastructure, Transport and Tourism's research shows around 10% people know about tsunami hazard map in Japan. However, people know about their evacuation places (buildings) through experienced drills once a year even though most people did not know about tsunami hazard map. We need wider spread of tsunami hazard with contingency of science (See the botom disaster handbook material's URL). California Emergency Management Agency (CEMA) team practically shows one good practice and solution to me. I followed their field trip in Catalina Island, California in Sep 2011. A team members are multidisciplinary specialists: A geologist, a GIS specialist, oceanographers in USC (tsunami numerical modeler) and a private company, a local policeman, a disaster manager, a local authority and so on. They check field based on their own specialties. They conduct an on-the-spot inspection of ambiguous locations between tsunami numerical model and real field conditions today. The data always become older. They pay attention not only to topographical conditions but also to social conditions: vulnerable people, elementary schools and so on. It takes a long time to check such field information, however tsunami hazard map based on numerical model should be this process. Tsunami scientists should not enter into the inhumane business by using tsunami numerical model. It includes accountability to society therefore scientists need scientific ethics and humanitarian attention. Should only tsunami scientist have responsibility for human life? Multidisciplinary approach is essential for mitigation like CEMA. I am taking on hazard map training course for disaster management officers from developing countries in JICA training course. I would like to discuss how to improve tsunami hazard map after the 2011 Tohoku tsunami experience in this presentation. A multidisciplinary exparts team of CEMA's tsunami hazard map

Machine-learning techniques for geochemical discrimination of 2011 Tohoku tsunami deposits

PubMed Central

Kuwatani, Tatsu; Nagata, Kenji; Okada, Masato; Watanabe, Takahiro; Ogawa, Yasumasa; Komai, Takeshi; Tsuchiya, Noriyoshi

2014-01-01

Geochemical discrimination has recently been recognised as a potentially useful proxy for identifying tsunami deposits in addition to classical proxies such as sedimentological and micropalaeontological evidence. However, difficulties remain because it is unclear which elements best discriminate between tsunami and non-tsunami deposits. Herein, we propose a mathematical methodology for the geochemical discrimination of tsunami deposits using machine-learning techniques. The proposed method can determine the appropriate combinations of elements and the precise discrimination plane that best discerns tsunami deposits from non-tsunami deposits in high-dimensional compositional space through the use of data sets of bulk composition that have been categorised as tsunami or non-tsunami sediments. We applied this method to the 2011 Tohoku tsunami and to background marine sedimentary rocks. After an exhaustive search of all 262,144 (= 218) combinations of the 18 analysed elements, we observed several tens of combinations with discrimination rates higher than 99.0%. The analytical results show that elements such as Ca and several heavy-metal elements are important for discriminating tsunami deposits from marine sedimentary rocks. These elements are considered to reflect the formation mechanism and origin of the tsunami deposits. The proposed methodology has the potential to aid in the identification of past tsunamis by using other tsunami proxies. PMID:25399750

Tsunami Casualty Model

NASA Astrophysics Data System (ADS)

Yeh, H.

2007-12-01

More than 4500 deaths by tsunamis were recorded in the decade of 1990. For example, the 1992 Flores Tsunami in Indonesia took away at least 1712 lives, and more than 2182 people were victimized by the 1998 Papua New Guinea Tsunami. Such staggering death toll has been totally overshadowed by the 2004 Indian Ocean Tsunami that claimed more than 220,000 lives. Unlike hurricanes that are often evaluated by economic losses, death count is the primary measure for tsunami hazard. It is partly because tsunamis kill more people owing to its short lead- time for warning. Although exact death tallies are not available for most of the tsunami events, there exist gender and age discriminations in tsunami casualties. Significant gender difference in the victims of the 2004 Indian Ocean Tsunami was attributed to women's social norms and role behavior, as well as cultural bias toward women's inability to swim. Here we develop a rational casualty model based on humans' limit to withstand the tsunami flows. The application to simple tsunami runup cases demonstrates that biological and physiological disadvantages also make a significant difference in casualty rate. It further demonstrates that the gender and age discriminations in casualties become most pronounced when tsunami is marginally strong and the difference tends to diminish as tsunami strength increases.

One year after the 1 April 2014 Iquique tsunami field survey along the coasts of Chile and Peru

NASA Astrophysics Data System (ADS)

Lagos, Marcelo; Fritz, Hermann M.

2015-04-01

One year ago on the evening of 1 April, 2014 a magnitude Mw 8.2 earthquake occurred off the coast of northern Chile off the coast of Pisagua within a region of historic quiescence termed the northern Chile seismic gap. The ensuing tsunami inundation caused mostly minor damage centered in Iquique and neighbouring stretches of coastline. Fortunately, ancestral knowledge from the past 1868 and 1877 tsunamis in the region along with the recent 2010 Maule tsunami, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were no tsunami victims; while a handful of fatalities were associated to earthquake induced building collapses and the physical stress of tsunami evacuation. The Arica native local scientist deployed overnight and started the tsunami survey in Iquique on the day after the earthquake. The international scientist joined the local effort from April 6 to 11, 2014. The international tsunami survey team (ITST) interviewed numerous eyewitnesses and documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 700 km stretch of coastline from the Mejillones Peninsula (23.5° S) north of Antofagasta in Chile up to Vila Vila (18.1° S) in southern Peru. We surveyed 30 locations with differential GPS and laser range finders. The tsunami impact peaked at Caleta Camarones exceeding 5 m in tsunami runup height. A significant variation in tsunami impact was observed along the coastlines of Chile and Peru both at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2014 Chile tsunami are compared against the 1868, 1877 and 2010 Chile tsunamis. Comparing to other similar magnitude events such as the 2007 Pisco tsunami in Peru the 1 April 2014 tsunami could have been significantly larger. The absence of a massive tsunami may mislead residents to believe another similarly minor tsunami may be generated after a potential future earthquake of similar magnitude. This April fool's day event poses significant challenges to community-based education raising tsunami awareness. The team educated residents about tsunami hazards since awareness programs are essential to save lives in locales at risk from near-field tsunamis.

Real-time determination of the worst tsunami scenario based on Earthquake Early Warning

NASA Astrophysics Data System (ADS)

Furuya, Takashi; Koshimura, Shunichi; Hino, Ryota; Ohta, Yusaku; Inoue, Takuya

2016-04-01

In recent years, real-time tsunami inundation forecasting has been developed with the advances of dense seismic monitoring, GPS Earth observation, offshore tsunami observation networks, and high-performance computing infrastructure (Koshimura et al., 2014). Several uncertainties are involved in tsunami inundation modeling and it is believed that tsunami generation model is one of the great uncertain sources. Uncertain tsunami source model has risk to underestimate tsunami height, extent of inundation zone, and damage. Tsunami source inversion using observed seismic, geodetic and tsunami data is the most effective to avoid underestimation of tsunami, but needs to expect more time to acquire the observed data and this limitation makes difficult to terminate real-time tsunami inundation forecasting within sufficient time. Not waiting for the precise tsunami observation information, but from disaster management point of view, we aim to determine the worst tsunami source scenario, for the use of real-time tsunami inundation forecasting and mapping, using the seismic information of Earthquake Early Warning (EEW) that can be obtained immediately after the event triggered. After an earthquake occurs, JMA's EEW estimates magnitude and hypocenter. With the constraints of earthquake magnitude, hypocenter and scaling law, we determine possible multi tsunami source scenarios and start searching the worst one by the superposition of pre-computed tsunami Green's functions, i.e. time series of tsunami height at offshore points corresponding to 2-dimensional Gaussian unit source, e.g. Tsushima et al., 2014. Scenario analysis of our method consists of following 2 steps. (1) Searching the worst scenario range by calculating 90 scenarios with various strike and fault-position. From maximum tsunami height of 90 scenarios, we determine a narrower strike range which causes high tsunami height in the area of concern. (2) Calculating 900 scenarios that have different strike, dip, length, width, depth and fault-position. Note that strike is limited with the range obtained from 90 scenarios calculation. From 900 scenarios, we determine the worst tsunami scenarios from disaster management point of view, such as the one with shortest travel time and the highest water level. The method was applied to a hypothetical-earthquake, and verified if it can effectively search the worst tsunami source scenario in real-time, to be used as an input of real-time tsunami inundation forecasting.

In Search of the Largest Possible Tsunami: An Example Following the 2011 Japan Tsunami

NASA Astrophysics Data System (ADS)

Geist, E. L.; Parsons, T.

2012-12-01

Many tsunami hazard assessments focus on estimating the largest possible tsunami: i.e., the worst-case scenario. This is typically performed by examining historic and prehistoric tsunami data or by estimating the largest source that can produce a tsunami. We demonstrate that worst-case assessments derived from tsunami and tsunami-source catalogs are greatly affected by sampling bias. Both tsunami and tsunami sources are well represented by a Pareto distribution. It is intuitive to assume that there is some limiting size (i.e., runup or seismic moment) for which a Pareto distribution is truncated or tapered. Likelihood methods are used to determine whether a limiting size can be determined from existing catalogs. Results from synthetic catalogs indicate that several observations near the limiting size are needed for accurate parameter estimation. Accordingly, the catalog length needed to empirically determine the limiting size is dependent on the difference between the limiting size and the observation threshold, with larger catalog lengths needed for larger limiting-threshold size differences. Most, if not all, tsunami catalogs and regional tsunami source catalogs are of insufficient length to determine the upper bound on tsunami runup. As an example, estimates of the empirical tsunami runup distribution are obtained from the Miyako tide gauge station in Japan, which recorded the 2011 Tohoku-oki tsunami as the largest tsunami among 51 other events. Parameter estimation using a tapered Pareto distribution is made both with and without the Tohoku-oki event. The catalog without the 2011 event appears to have a low limiting tsunami runup. However, this is an artifact of undersampling. Including the 2011 event, the catalog conforms more to a pure Pareto distribution with no confidence in estimating a limiting runup. Estimating the size distribution of regional tsunami sources is subject to the same sampling bias. Physical attenuation mechanisms such as wave breaking likely limit the maximum tsunami runup at a particular site. However, historic and prehistoric data alone cannot determine the upper bound on tsunami runup. Because of problems endemic to sampling Pareto distributions of tsunamis and their sources, we recommend that tsunami hazard assessment be based on a specific design probability of exceedance following a pure Pareto distribution, rather than attempting to determine the worst-case scenario.

Paleo-tsunami history along the northern Japan Trench: evidence from Noda Village, northern Sanriku coast, Japan

NASA Astrophysics Data System (ADS)

Inoue, Taiga; Goto, Kazuhisa; Nishimura, Yuichi; Watanabe, Masashi; Iijima, Yasutaka; Sugawara, Daisuke

2017-12-01

Throughout history, large tsunamis have frequently affected the Sanriku area of the Pacific coast of the Tohoku region, Japan, which faces the Japan Trench. Although a few studies have examined paleo-tsunami deposits along the Sanriku coast, additional studies of paleo-earthquakes and tsunamis are needed to improve our knowledge of the timing, recurrence interval, and size of historical and pre-historic tsunamis. At Noda Village, in Iwate Prefecture on the northern Sanriku coast, we found at least four distinct gravelly sand layers based on correlation and chronological data. Sedimentary features such as grain size and thickness suggest that extreme waves from the sea formed these layers. Numerical modeling of storm waves further confirmed that even extremely large storm waves cannot account for the distribution of the gravelly sand layers, suggesting that these deposits are highly likely to have formed by tsunami waves. The numerical method of storm waves can be useful to identify sand layers as tsunami deposits if the deposits are observed far inland or at high elevations. The depositional age of the youngest tsunami deposit is consistent with the AD 869 Jogan earthquake tsunami, a possible predecessor of the AD 2011 Tohoku-oki tsunami. If this is the case, then the study site currently defines the possible northern extent of the AD 869 Jogan tsunami deposit, which is an important step in improving the tsunami source model of the AD 869 Jogan tsunami. Our results suggest that four large tsunamis struck the Noda site between 1100 and 2700 cal BP. The local tsunami sizes are comparable to the AD 2011 and AD 1896 Meiji Sanriku tsunamis, considering the landward extent of each tsunami deposit.

Developing Tsunami Evacuation Plans, Maps, And Procedures: Pilot Project in Central America

NASA Astrophysics Data System (ADS)

Arcos, N. P.; Kong, L. S. L.; Arcas, D.; Aliaga, B.; Coetzee, D.; Leonard, J.

2015-12-01

In the End-to-End tsunami warning chain, once a forecast is provided and a warning alert issued, communities must know what to do and where to go. The 'where to' answer would be reliable and practical community-level tsunami evacuation maps. Following the Exercise Pacific Wave 2011, a questionnaire was sent to the 46 Member States of Pacific Tsunami Warning System (PTWS). The results revealed over 42 percent of Member States lacked tsunami mass coastal evacuation plans. Additionally, a significant gap in mapping was exposed as over 55 percent of Member States lacked tsunami evacuation maps, routes, signs and assembly points. Thereby, a significant portion of countries in the Pacific lack appropriate tsunami planning and mapping for their at-risk coastal communities. While a variety of tools exist to establish tsunami inundation areas, these are inconsistent while a methodology has not been developed to assist countries develop tsunami evacuation maps, plans, and procedures. The International Tsunami Information Center (ITIC) and partners is leading a Pilot Project in Honduras demonstrating that globally standardized tools and methodologies can be applied by a country, with minimal tsunami warning and mitigation resources, towards the determination of tsunami inundation areas and subsequently community-owned tsunami evacuation maps and plans for at-risk communities. The Pilot involves a 1- to 2-year long process centered on a series of linked tsunami training workshops on: evacuation planning, evacuation map development, inundation modeling and map creation, tsunami warning & emergency response Standard Operating Procedures (SOPs), and conducting tsunami exercises (including evacuation). The Pilot's completion is capped with a UNESCO/IOC document so that other countries can replicate the process in their tsunami-prone communities.

Earthquake and Tsunami booklet based on two Indonesia earthquakes

NASA Astrophysics Data System (ADS)

Hayashi, Y.; Aci, M.

2014-12-01

Many destructive earthquakes occurred during the last decade in Indonesia. These experiences are very important precepts for the world people who live in earthquake and tsunami countries. We are collecting the testimonies of tsunami survivors to clarify successful evacuation process and to make clear the characteristic physical behaviors of tsunami near coast. We research 2 tsunami events, 2004 Indian Ocean tsunami and 2010 Mentawai slow earthquake tsunami. Many video and photographs were taken by people at some places in 2004 Indian ocean tsunami disaster; nevertheless these were few restricted points. We didn't know the tsunami behavior in another place. In this study, we tried to collect extensive information about tsunami behavior not only in many places but also wide time range after the strong shake. In Mentawai case, the earthquake occurred in night, so there are no impressive photos. To collect detail information about evacuation process from tsunamis, we contrived the interview method. This method contains making pictures of tsunami experience from the scene of victims' stories. In 2004 Aceh case, all survivors didn't know tsunami phenomena. Because there were no big earthquakes with tsunami for one hundred years in Sumatra region, public people had no knowledge about tsunami. This situation was highly improved in 2010 Mentawai case. TV programs and NGO or governmental public education programs about tsunami evacuation are widespread in Indonesia. Many people know about fundamental knowledge of earthquake and tsunami disasters. We made drill book based on victim's stories and painted impressive scene of 2 events. We used the drill book in disaster education event in school committee of west Java. About 80 % students and teachers evaluated that the contents of the drill book are useful for correct understanding.

The Puerto Rico Component of the National Tsunami Hazard and Mitigation Program (PR-NTHMP)

NASA Astrophysics Data System (ADS)

Vanacore, E. A.; Huerfano Moreno, V. A.; Lopez, A. M.

2015-12-01

The Caribbean region has a documented history of damaging tsunamis that have affected coastal areas. Of particular interest is the Puerto Rico - Virgin Islands (PRVI) region, where the proximity of the coast to prominent tectonic faults would result in near-field tsunamis. Tsunami hazard assessment, detection capabilities, warning, education and outreach efforts are common tools intended to reduce loss of life and property. It is for these reasons that the PRSN is participating in an effort with local and federal agencies to develop tsunami hazard risk reduction strategies under the NTHMP. This grant supports the TsunamiReady program, which is the base of the tsunami preparedness and mitigation in PR. In order to recognize threatened communities in PR as TsunamiReady by the US NWS, the PR Component of the NTHMP have identified and modeled sources for local, regional and tele-tsunamis and the results of simulations have been used to develop tsunami response plans. The main goal of the PR-NTHMP is to strengthen resilient coastal communities that are prepared for tsunami hazards, and recognize PR as TsunamiReady. Evacuation maps were generated in three phases: First, hypothetical tsunami scenarios of potential underwater earthquakes were developed, and these scenarios were then modeled through during the second phase. The third phase consisted in determining the worst-case scenario based on the Maximum of Maximums (MOM). Inundation and evacuation zones were drawn on GIS referenced maps and aerial photographs. These products are being used by emergency managers to educate the public and develop mitigation strategies. Maps and related evacuation products, like evacuation times, can be accessed online via the PR Tsunami Decision Support Tool. Based on these evacuation maps, tsunami signs were installed, vulnerability profiles were created, communication systems to receive and disseminate tsunami messages were installed in each TWFP, and tsunami response plans were approved. Also, the existing tsunami protocol and criteria in the PR/VI was updated. This paper describes the PR-NTHMP recent outcomes, including the real time monitoring as well as the protocols used to broadcast tsunami messages. The paper highlights tsunami hazards assessment, detection, warning, education and outreach efforts in Puerto Rico.

Possible worst-case tsunami scenarios around the Marmara Sea from combined earthquake and landslide sources

NASA Astrophysics Data System (ADS)

Latcharote, Panon; Suppasri, Anawat; Imamura, Fumihiko; Aytore, Betul; Yalciner, Ahmet Cevdet

2016-12-01

This study evaluates tsunami hazards in the Marmara Sea from possible worst-case tsunami scenarios that are from submarine earthquakes and landslides. In terms of fault-generated tsunamis, seismic ruptures can propagate along the North Anatolian Fault (NAF), which has produced historical tsunamis in the Marmara Sea. Based on the past studies, which consider fault-generated tsunamis and landslide-generated tsunamis individually, future scenarios are expected to generate tsunamis, and submarine landslides could be triggered by seismic motion. In addition to these past studies, numerical modeling has been applied to tsunami generation and propagation from combined earthquake and landslide sources. In this study, tsunami hazards are evaluated from both individual and combined cases of submarine earthquakes and landslides through numerical tsunami simulations with a grid size of 90 m for bathymetry and topography data for the entire Marmara Sea region and validated with historical observations from the 1509 and 1894 earthquakes. This study implements TUNAMI model with a two-layer model to conduct numerical tsunami simulations, and the numerical results show that the maximum tsunami height could reach 4.0 m along Istanbul shores for a full submarine rupture of the NAF, with a fault slip of 5.0 m in the eastern and western basins of the Marmara Sea. The maximum tsunami height for landslide-generated tsunamis from small, medium, and large of initial landslide volumes (0.15, 0.6, and 1.5 km3, respectively) could reach 3.5, 6.0, and 8.0 m, respectively, along Istanbul shores. Possible tsunamis from submarine landslides could be significantly higher than those from earthquakes, depending on the landslide volume significantly. These combined earthquake and landslide sources only result in higher tsunami amplitudes for small volumes significantly because of amplification within the same tsunami amplitude scale (3.0-4.0 m). Waveforms from all the coasts around the Marmara Sea indicate that other residential areas might have had a high risk of tsunami hazards from submarine landslides, which can generate higher tsunami amplitudes and shorter arrival times, compared to Istanbul.

A simple model for calculating tsunami flow speed from tsunami deposits

USGS Publications Warehouse

Jaffe, B.E.; Gelfenbuam, G.

2007-01-01

This paper presents a simple model for tsunami sedimentation that can be applied to calculate tsunami flow speed from the thickness and grain size of a tsunami deposit (the inverse problem). For sandy tsunami deposits where grain size and thickness vary gradually in the direction of transport, tsunami sediment transport is modeled as a steady, spatially uniform process. The amount of sediment in suspension is assumed to be in equilibrium with the steady portion of the long period, slowing varying uprush portion of the tsunami. Spatial flow deceleration is assumed to be small and not to contribute significantly to the tsunami deposit. Tsunami deposits are formed from sediment settling from the water column when flow speeds on land go to zero everywhere at the time of maximum tsunami inundation. There is little erosion of the deposit by return flow because it is a slow flow and is concentrated in topographic lows. Variations in grain size of the deposit are found to have more effect on calculated tsunami flow speed than deposit thickness. The model is tested using field data collected at Arop, Papua New Guinea soon after the 1998 tsunami. Speed estimates of 14??m/s at 200??m inland from the shoreline compare favorably with those from a 1-D inundation model and from application of Bernoulli's principle to water levels on buildings left standing after the tsunami. As evidence that the model is applicable to some sandy tsunami deposits, the model reproduces the observed normal grading and vertical variation in sorting and skewness of a deposit formed by the 1998 tsunami.

The U.S. National Tsunami Hazard Mitigation Program: Successes in Tsunami Preparedness

NASA Astrophysics Data System (ADS)

Whitmore, P.; Wilson, R. I.

2012-12-01

Formed in 1995 by Congressional Action, the National Tsunami Hazards Mitigation Program (NTHMP) provides the framework for tsunami preparedness activities in the United States. The Program consists of the 28 U.S. coastal states, territories, and commonwealths (STCs), as well as three Federal agencies: the National Oceanic and Atmospheric Administration (NOAA), the Federal Emergency Management Agency (FEMA), and the United States Geological Survey (USGS). Since its inception, the NTHMP has advanced tsunami preparedness in the United States through accomplishments in many areas of tsunami preparedness: - Coordination and funding of tsunami hazard analysis and preparedness activities in STCs; - Development and execution of a coordinated plan to address education and outreach activities (materials, signage, and guides) within its membership; - Lead the effort to assist communities in meeting National Weather Service (NWS) TsunamiReady guidelines through development of evacuation maps and other planning activities; - Determination of tsunami hazard zones in most highly threatened coastal communities throughout the country by detailed tsunami inundation studies; - Development of a benchmarking procedure for numerical tsunami models to ensure models used in the inundation studies meet consistent, NOAA standards; - Creation of a national tsunami exercise framework to test tsunami warning system response; - Funding community tsunami warning dissemination and reception systems such as sirens and NOAA Weather Radios; and, - Providing guidance to NOAA's Tsunami Warning Centers regarding warning dissemination and content. NTHMP activities have advanced the state of preparedness of United States coastal communities, and have helped save lives and property during recent tsunamis. Program successes as well as future plans, including maritime preparedness, are discussed.

Beyond night float? The impact of call structure on internal medicine residents.

PubMed

Rosenberg, M; McNulty, D

1995-02-01

Limitation of resident working hours has been a critical issue for training programs in recent years. At Providence Medical Center, residents and faculty collaborated in developing goals, implementation strategies, and an evaluation process for a new ward float system. The goals of the float system were to reduce fatigue, facilitate education, maintain continuity of care, and minimize the negative impact of training on residents' personal lives. Evaluation revealed: 1) 74% of the residents preferred Providence Medical Center float system (PMCF) to either night float (NF) (13%) or standard every-fourth-night call (EFNC) (13%); and 2) PMCF was perceived to ensure quality patient care to a greater degree than was NF, to better facilitate resident education than was NF, and to have a less negative impact on personal lives than was EFNC.

Experimental and Numerical Investigations of Floating Breakwater Performance.

USDA-ARS?s Scientific Manuscript database

Floating breakwaters are commonly used to protect small marinas and for shoreline erosion control in coastal areas. They are efficient wave attenuation structures for relatively short waves and shallow water depths. The main objective of the current study is to investigate the hydrodynamic interacti...

Historic Tsunami in the Indian Ocean

NASA Astrophysics Data System (ADS)

Dominey-Howes, D.; Cummins, P. R.; Burbidge, D.

2005-12-01

The 2004 Boxing Day Tsunami dramatically highlighted the need for a better understanding of the tsunami hazard in the Indian Ocean. One of the most important foundations on which to base such an assessment is knowledge of tsunami that have affected the region in the historical past. We present a summary of the previously published catalog of Indian Ocean tsunami and the results of a preliminary search of archival material held at the India Records Office at the British Library in London. We demonstrate that in some cases, normal tidal movements and floods associated with tropical cyclones have been erroneously listed as tsunami. We summarise interesting archival material for tsunami that occurred in 1945, 1941, 1881, 1819, 1762 and a tsunami in 1843 not previously identified or reported. We also note the recent discovery, by a Canadian team during a post-tsunami survey following the 2004 Boxing Day Tsunami, of archival evidence that the Great Sumatra Earthquake of 1833 generated a teletsunami. Open ocean wave heights are calculated for some of the historical tsunami and compared with those of the Boxing Day Tsunami.

Tsunami vulnerability assessment mapping for the west coast of Peninsular Malaysia using a geographical information system (GIS)

NASA Astrophysics Data System (ADS)

Najihah, R.; Effendi, D. M.; Hairunnisa, M. A.; Masiri, K.

2014-02-01

The catastrophic Indian Ocean tsunami of 26 December 2004 raised a number of questions for scientist and politicians on how to deal with the tsunami risk and assessment in coastal regions. This paper discusses the challenges in tsunami vulnerability assessment and presents the result of tsunami disaster mapping and vulnerability assessment study for West Coast of Peninsular Malaysia. The spatial analysis was carried out using Geographical Information System (GIS) technology to demarcate spatially the tsunami affected village's boundary and suitable disaster management program can be quickly and easily developed. In combination with other thematic maps such as road maps, rail maps, school maps, and topographic map sheets it was possible to plan the accessibility and shelter to the affected people. The tsunami vulnerability map was used to identify the vulnerability of villages/village population to tsunami. In the tsunami vulnerability map, the intensity of the tsunami was classified as hazard zones based on the inundation level in meter (contour). The approach produced a tsunami vulnerability assessment map consists of considering scenarios of plausible extreme, tsunami-generating events, computing the tsunami inundation levels caused by different events and scenarios and estimating the possible range of casualties for computing inundation levels. The study provides an interactive means to identify the tsunami affected areas after the disaster and mapping the tsunami vulnerable village before for planning purpose were the essential exercises for managing future disasters.

Japanese Experience with Long-term Recovery from the 2011 Tohoku　Earthquake and Tsunami Disaster

NASA Astrophysics Data System (ADS)

Hayashi, H.

2015-12-01

On March 11, 2011, a huge tsunami disaster hit Pacific coast of Tohoku region due to a magnitude of 9.0 earthquake, and killed almost 20,000 people. It was also the beginning of long-term recovery to prepare for next tsunami attack in the future. In this presentation, I would like to review the recovery process from the following five elements: quantification of tsunami hazards, public education, evacuation model, land-use planning, and real-time tsunami warning. It should be noted that there are lessons from the 2011 event at two different levels: national level and prefecture levels. In relation to the quantification of tsunami hazard and real-time tsunami warning, it followed a big change in tsunami policy at national level such as setting up two levels of tsunami scenarios for tsunami preparedness and mitigation: Level 1 tsunami (L1) and Level 2 tsunami (L2). L1 is the tsunami risk with 50 year return period, and L2 is the one with 1,000 year return period. As for public education, evacuation model, and land-use planning, There existed a big difference for what happened in the northern half of the coast and the southern half. Northern half of the coast belongs to Iwate Prefecture whose geography is rias coast. People in the Rias coast of Iwate Prefecture has been hit many times by tsunami on the average of about 50 years. With these many experiences, they succeeded in reducing the number of mortality down to 4,000 in comparison with 20,000 at the 1886 tsunami disaster. Most of the Southern half belongs to Miyagi Prefecture whose geography is coastal plain. People in the coastal plain in Miyagi Prefecture has little experience with tsunami disaster and end up with 14,000 deaths due to tsunami attack. The differences in the past tsunami experiences in these two prefectures resulted in big differences in public education, evacuation model, and land-use planning.

The FASTER Approach: A New Tool for Calculating Real-Time Tsunami Flood Hazards

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Cross, A.; Johnson, L.; Miller, K.; Nicolini, T.; Whitmore, P.

2014-12-01

In the aftermath of the 2010 Chile and 2011 Japan tsunamis that struck the California coastline, emergency managers requested that the state tsunami program provide more detailed information about the flood potential of distant-source tsunamis well ahead of their arrival time. The main issue is that existing tsunami evacuation plans call for evacuation of the predetermined "worst-case" tsunami evacuation zone (typically at a 30- to 50-foot elevation) during any "Warning" level event; the alternative is to not call an evacuation at all. A solution to provide more detailed information for secondary evacuation zones has been the development of tsunami evacuation "playbooks" to plan for tsunami scenarios of various sizes and source locations. To determine a recommended level of evacuation during a distant-source tsunami, an analytical tool has been developed called the "FASTER" approach, an acronym for factors that influence the tsunami flood hazard for a community: Forecast Amplitude, Storm, Tides, Error in forecast, and the Run-up potential. Within the first couple hours after a tsunami is generated, the National Tsunami Warning Center provides tsunami forecast amplitudes and arrival times for approximately 60 coastal locations in California. At the same time, the regional NOAA Weather Forecast Offices in the state calculate the forecasted coastal storm and tidal conditions that will influence tsunami flooding. Providing added conservatism in calculating tsunami flood potential, we include an error factor of 30% for the forecast amplitude, which is based on observed forecast errors during recent events, and a site specific run-up factor which is calculated from the existing state tsunami modeling database. The factors are added together into a cumulative FASTER flood potential value for the first five hours of tsunami activity and used to select the appropriate tsunami phase evacuation "playbook" which is provided to each coastal community shortly after the forecast is provided.

Structural analysis and design for the development of floating photovoltaic energy generation system

NASA Astrophysics Data System (ADS)

Yoon, S. J.; Joo, H. J.; Kim, S. H.

2018-06-01

In this paper, we discussed the structural analysis and design for the development of floating photovoltaic energy generation system. Series of research conducted to develop the system from the analysis and design of the structural system to the installation of the system discussed. In the structural system supporting solar panels PFRP materials and SMC FRP materials used. A unit module structure is fabricated and then the unit module structures are connected each other to assemble whole PV energy generation complex. This system connected directly to the power grid system. In addition, extensive monitoring for the efficiency of electricity generation and the soundness of the structural system is in progress for the further system enhancement.

A Robotic Communications Gateway for Ocean Observations

NASA Astrophysics Data System (ADS)

Orcutt, J. A.; Berger, J.; Laske, G.; Babcock, J.

2015-12-01

We describe a new technology that can provide real-time telemetry of sensor data from the ocean bottom. The breakthrough technology that makes this system possible is an autonomous surface vehicle called the Wave Glider developed by Liquid Robotics, Inc. of Sunnyvale, CA., which harvests wave and solar energy for motive and electrical power. The free-floating surface communications gateway uses a Liquid Robotics wave glider comprising a surfboard-sized float towed by a tethered, submerged glider, which converts wave motion into thrust. For navigation, the wave glider is equipped with a small computer, a GPS receiver, a rudder, solar panels and batteries, and an Iridium satellite modem. Acoustic communications connect the subsea instruments and the surface gateway while communications between the gateway and land are provided by the Iridium satellite constellation. Wave gliders have demonstrated trans-oceanic range and long-term station keeping capabilities. The topside acoustics communications package is mounted in a shallow tow body, which uses a WHOI micro modem and a Benthos low frequency, directional transducer. A matching bottom side modem and transducer are mounted on the ocean bottom package. Tests of the surface gateway in 4000 m of water demonstrated an acoustic efficiency of approximately 256 bits/J. For example, it has the ability to send four channels of compressed, one sample per second data from the ocean bottom to the gateway with an average power draw of approximately 0.36 W and a latency of about three minutes. This gateway is used to send near-real-time data from a broadband ocean bottom seismic observatory; we are presently designing and constructing a seafloor package with a two-year operational life. We have found that for frequencies f where f<10mHz, 35mHz < f < 120mHz and f>~3Hz, the vertical component, seafloor system noise characteristics are generally superior to similar observatories on land. Increasing the density of these stations over the majority of the surface of Earth; that is, the oceans will greatly enhance the resolution of deep Earth structure and serve civil needs including tsunami warning. The robotic technology is readily applicable for other ocean observations.

The 2011 Tohoku Tsunami on the Coast of Mexico: A Case Study

NASA Astrophysics Data System (ADS)

Zaytsev, Oleg; Rabinovich, Alexander B.; Thomson, Richard E.

2017-08-01

The Tohoku (East Japan) earthquake of 11 March 2011 ( M w 9.0) generated a great trans-oceanic tsunami that spread throughout the Pacific Ocean, where it was measured by numerous coastal tide gauges and open-ocean DART (Deep-ocean Assessment and Reporting of Tsunamis) stations. Statistical and spectral analyses of the tsunami waves recorded along the Pacific coast of Mexico have enabled us to estimate the principal parameters of the waves along the coast and to compare statistical features of the tsunami with other tsunamis recorded on this coast. We identify coastal "hot spots"—Manzanillo, Zihuatanejo, Acapulco, and Ensenada—corresponding to sites having highest tsunami hazard potential, where wave heights during the 2011 event exceeded 1.5-2 m and tsunami-induced currents were strong enough to close port operations. Based on a joint spectral analysis of the tsunamis and background noise, we reconstructed the spectra of tsunami waves in the deep ocean and found that, with the exception of the high-frequency spectral band (>5 cph), the spectra are in close agreement with the "true" tsunami spectra determined from DART bottom pressure records. The departure of the high-frequency spectra in the coastal region from the deep-sea spectra is shown to be related to background infragravity waves generated in the coastal zone. The total energy and frequency content of the Tohoku tsunami is compared with the corresponding results for the 2010 Chilean tsunami. Our findings show that the integral open-ocean tsunami energy, I 0, was 2.30 cm2, or approximately 1.7 times larger than for the 2010 event. Comparison of this parameter with the mean coastal tsunami variance (451 cm2) indicates that tsunami waves propagating onshore from the open ocean amplified by 14 times; the same was observed for the 2010 tsunami. The "tsunami colour" (frequency content) for the 2011 Tohoku tsunami was "red", with about 65% of the total energy associated with low-frequency waves at frequencies <1.7 cph (periods >35 min). The "red colour" (i.e., the prevalence of low-frequency waves) in the 2011 Tohoku, as well as in the 2010 Chile tsunamis, is explained by the large extension of the source areas. In contrast, the 2014 and 2015 Chilean earthquakes had much smaller source areas and, consequently, induced "bluish" (high-frequency) tsunamis.

The tsunami phenomenon

NASA Astrophysics Data System (ADS)

Röbke, B. R.; Vött, A.

2017-12-01

With human activity increasingly concentrating on coasts, tsunamis (from Japanese tsu = harbour, nami = wave) are a major natural hazard to today's society. Stimulated by disastrous tsunami impacts in recent years, for instance in south-east Asia (2004) or in Japan (2011), tsunami science has significantly flourished, which has brought great advances in hazard assessment and mitigation plans. Based on tsunami research of the last decades, this paper provides a thorough treatise on the tsunami phenomenon from a geoscientific point of view. Starting with the wave features, tsunamis are introduced as long shallow water waves or wave trains crossing entire oceans without major energy loss. At the coast, tsunamis typically show wave shoaling, funnelling and resonance effects as well as a significant run-up and backflow. Tsunami waves are caused by a sudden displacement of the water column due to a number of various trigger mechanisms. Such are earthquakes as the main trigger, submarine and subaerial mass wastings, volcanic activity, atmospheric disturbances (meteotsunamis) and cosmic impacts, as is demonstrated by giving corresponding examples from the past. Tsunamis are known to have a significant sedimentary and geomorphological off- and onshore response. So-called tsunamites form allochthonous high-energy deposits that are left at the coast during tsunami landfall. Tsunami deposits show typical sedimentary features, as basal erosional unconformities, fining-upward and -landward, a high content of marine fossils, rip-up clasts from underlying units and mud caps, all reflecting the hydrodynamic processes during inundation. The on- and offshore behaviour of tsunamis and related sedimentary processes can be simulated using hydro- and morphodynamic numerical models. The paper provides an overview of the basic tsunami modelling techniques, including discretisation, guidelines for appropriate temporal and spatial resolution as well as the nesting method. Furthermore, the Boussinesq approximation-a simplification of the three-dimensional Navier-Stokes equations-is presented as a basic theory behind numerical tsunami models, which adequately reflects the non-linear, dispersive wave behaviour of tsunamis. The fully non-linear Boussinesq equations allow the simulation of tsunamis e.g. in the form of N-waves. Based on the various subtopics presented, recommendations for future multidisciplinary tsunami research are made. It is especially discussed how the combination of sedimentary and geomorphological tsunami field traces and numerical modelling techniques can contribute to derive locally relevant tsunami sources and to improve the assessment of tsunami hazards considering the individual pre-/history and physiogeographical setting of a specific region.

The Puerto Rico Component of the National Tsunami Hazard and Mitigation Program Pr-Nthmp

NASA Astrophysics Data System (ADS)

Huerfano Moreno, V. A.; Hincapie-Cardenas, C. M.

2014-12-01

Tsunami hazard assessment, detection, warning, education and outreach efforts are intended to reduce losses to life and property. The Puerto Rico Seismic Network (PRSN) is participating in an effort with local and federal agencies, to developing tsunami hazard risk reduction strategies under the National Tsunami Hazards and Mitigation Program (NTHMP). This grant supports the TsunamiReady program which is the base of the tsunami preparedness and mitigation in PR. The Caribbean region has a documented history of damaging tsunamis that have affected coastal areas. The seismic water waves originating in the prominent fault systems around PR are considered to be a near-field hazard for Puerto Rico and the Virgin islands (PR/VI) because they can reach coastal areas within a few minutes after the earthquake. Sources for local, regional and tele tsunamis have been identified and modeled and tsunami evacuation maps were prepared for PR. These maps were generated in three phases: First, hypothetical tsunami scenarios on the basis of the parameters of potential underwater earthquakes were developed. Secondly, each of these scenarios was simulated. The third step was to determine the worst case scenario (MOM). The run-ups were drawn on GIS referenced maps and aerial photographs. These products are being used by emergency managers to educate the public and develop mitigation strategies. Online maps and related evacuation products are available to the public via the PR-TDST (PR Tsunami Decision Support Tool). Currently all the 44 coastal municipalities were recognized as TsunamiReady by the US NWS. The main goal of the program is to declare Puerto Rico as TsunamiReady, including two cities that are not coastal but could be affected by tsunamis. Based on these evacuation maps, tsunami signs were installed, vulnerability profiles were created, communication systems to receive and disseminate tsunami messages were installed in each TWFP, and tsunami response plans were approved. Also, the existing tsunami protocol and criteria in the PR/VI was updated. This paper describes the PR-NTHMP project, including the real time earthquake and tsunami monitoring as well as the specific protocols used to broadcast tsunami messages. The paper highlights tsunami hazards assessment, detection, warning, education and outreach in Puerto Rico.

U.S. states and territories national tsunami hazard assessment, historic record and sources for waves

NASA Astrophysics Data System (ADS)

Dunbar, P. K.; Weaver, C.

2007-12-01

In 2005, the U.S. National Science and Technology Council (NSTC) released a joint report by the sub-committee on Disaster Reduction and the U.S. Group on Earth Observations titled Tsunami Risk Reduction for the United States: A Framework for Action (Framework). The Framework outlines the President's&pstrategy for reducing the United States tsunami risk. The first specific action called for in the Framework is to "Develop standardized and coordinated tsunami hazard and risk assessments for all coastal regions of the United States and its territories." Since NOAA is the lead agency for providing tsunami forecasts and warnings and NOAA's National Geophysical Data Center (NGDC) catalogs information on global historic tsunamis, NOAA/NGDC was asked to take the lead in conducting the first national tsunami hazard assessment. Earthquakes or earthquake-generated landslides caused more than 85% of the tsunamis in the NGDC tsunami database. Since the United States Geological Survey (USGS) conducts research on earthquake hazards facing all of the United States and its territories, NGDC and USGS partnered together to conduct the first tsunami hazard assessment for the United States and its territories. A complete tsunami hazard and risk assessment consists of a hazard assessment, exposure and vulnerability assessment of buildings and people, and loss assessment. This report is an interim step towards a tsunami risk assessment. The goal of this report is provide a qualitative assessment of the United States tsunami hazard at the national level. Two different methods are used to assess the U.S. tsunami hazard. The first method involves a careful examination of the NGDC historical tsunami database. This resulted in a qualitative national tsunami hazard assessment based on the distribution of runup heights and the frequency of runups. Although tsunami deaths are a measure of risk rather than hazard, the known tsunami deaths found in the NGDC database search were compared with the qualitative assessments based on frequency and amplitude. The second method to assess tsunami hazard involved using the USGS earthquake databases to search for possible earthquake sources near American coastlines to extend the NOAA/NGDC tsunami databases backward in time. The qualitative tsunami hazard assessment based on the results of the NGDC and USGS database searches will be presented.

A Study of the Effects of Seafloor Topography on Tsunami Propagation

NASA Astrophysics Data System (ADS)

Ohata, T.; Mikada, H.; Goto, T.; Takekawa, J.

2011-12-01

For tsunami disaster mitigation, we consider the phenomena related to tsunami in terms of the generation, propagation, and run-up to the coast. With consideration for these three phenomena, we have to consider tsunami propagation to predict the arrival time and the run-up height of tsunami. Numerical simulations of tsunami that propagates from the source location to the coast have been widely used to estimate these important parameters. When a tsunami propagates, however, reflected and scattered waves arrive as later phases of tsunami. These waves are generated by the changes of water depth, and could influence the height estimation, especially in later phases. The maximum height of tsunami could be observed not as the first arrivals but as the later phases, therefore it is necessary to consider the effects of the seafloor topography on tsunami propagation. Since many simulations, however, mainly focus on the prediction of the first arrival times and the initial height of tsunami, it is difficult to simulate the later phases that are important for the tsunami disaster mitigation in the conventional methods. In this study, we investigate the effects of the seafloor topography on tsunami propagation after accommodating a tsunami simulation to the superposition of reflected and refracted waves caused by the smooth changes of water depths. Developing the new numerical code, we consider how the effects of the sea floor topography affect on the tsunami propagation, comparing with the tsunami simulated by the conventional method based on the liner long wave theory. Our simulation employs the three dimensional in-equally spaced grids in finite difference method (FDM) to introduce the real seafloor topography. In the simulation, we import the seafloor topography from the real bathymetry data near the Sendai-Bay, off the northeast Tohoku region, Japan, and simulate the tsunami propagation over the varying seafloor topography there. Comparing with the tsunami simulated by the conventional method based on the liner long wave theory, we found that the amplitudes of tsunamis are different from each other for the two simulations. The degree of the amplification of the height of tsunami in our method is larger than that in the conventional one. The height of the later phases of the tsunamis shows the discrepancy between the two results. We would like to conclude that the real changes of water depth affect the prediction of tsunami propagation and the maximum height. Because of the effects of the seafloor topography, the amplitude of the later phases is sometimes larger than the former ones. Due to the inclusion of such effects by the real topography, we believe our method lead to a higher accuracy of prediction of tsunami later phases, which would be effective for tsunami disaster mitigation.

Estimation of human damage and economic loss of buildings for the worst-credible scenario of tsunami inundation in the city of Augusta, Italy

NASA Astrophysics Data System (ADS)

Pagnoni, Gianluca; Tinti, Stefano

2017-04-01

The city of Augusta is located in the southern part of the eastern coast of Sicily. Italian tsunami catalogue and paleo-tsunami surveys indicate that at least 7 events of tsunami affected the bay of Augusta in the last 4,000 years, two of which are associated with earthquakes (1169 and 1693) that destroyed the city. For these reasons Augusta has been chosen in the project ASTARTE as a test site for the study of issues related to tsunami hazard and risk. In last two years we studied hazard through the approach of the worst-case credible scenario and carried out vulnerability and damage analysis for buildings. In this work, we integrate that research, and estimate the damage to people and the economic loss of buildings due to structural damage. As regards inundation, we assume both uniform inundation levels (bath-tub hypothesis) and inundation data resulting from the worst-case scenario elaborated for the area by Armigliato et al. (2015). Human damage is calculated in three steps using the method introduced by Pagnoni et al. (2016) following the work by Terrier et al. (2012) and by Koshimura et al. (2009). First, we use census data to estimate the number of people present in each residential building affected by inundation; second, based on water column depth and building type, we evaluate the level of damage to people; third, we provide an estimate of fatalities. The economic loss is computed for two types of buildings (residential and trade-industrial) by using data on inundation and data from the real estate market. This study was funded by the EU Project ASTARTE - "Assessment, STrategy And Risk Reduction for Tsunamis in Europe", Grant 603839, 7th FP (ENV.2013.6.4-3)

The Great East-Japan Earthquake and devastating tsunami: an update and lessons from the past Great Earthquakes in Japan since 1923.

PubMed

Ishigaki, Akemi; Higashi, Hikari; Sakamoto, Takako; Shibahara, Shigeki

2013-04-01

Japan has a long history of fighting against great earthquakes that cause structural damage/collapses, fires and/or tsunami. On March 11, 2011 at 14:46 (Friday), the Great East-Japan Earthquake (magnitude 9.0) attacked the Tohoku region (northeastern Japan), which includes Sendai City. The earthquake generated a devastating tsunami, leading to unprecedented disasters (~18,500 victims) in coastal areas of Iwate, Miyagi and Fukushima prefectures, despite the fact that people living in the Tohoku region are well trained for tsunami-evacuation procedures, with the mindset of "Tsunami, ten-den-ko." This code means that each person should evacuate individually upon an earthquake. Sharing this rule, children and parents can escape separately from schools, houses or workplaces, without worrying about each other. The concept of ten-den-ko (individual evacuation) is helpful for people living in coastal areas of earthquake-prone zones around the world. It is also important to construct safe evacuation centers, because the March 11(th) tsunami killed people who had evacuated to evacuation sites. We summarize the current conditions of people living in the disaster-stricken areas, including the consequences of the Fukushima nuclear accident. We also describe the disaster responses as the publisher of the Tohoku Journal of Experimental Medicine (TJEM), located in Sendai, with online support from Tokyo. In 1923, the Great Kanto Earthquake (magnitude 7.9) evoked a massive fire that destroyed large areas of Tokyo (~105,000 victims), including the print company for TJEM, but the Wistar Institute printed three TJEM issues in 1923 in Philadelphia. Mutual aid relationships should be established between distant cities to survive future disasters.

Multi-GPGPU Tsunami simulation at Toyama-bay

NASA Astrophysics Data System (ADS)

Furuyama, Shoichi; Ueda, Yuki

2017-07-01

Accelerated multi General Purpose Graphics Processing Unit (GPGPU) calculation for Tsunami run-up simulation was achieved at the wide area (whole Toyama-bay in Japan) by faster computation technique. Toyama-bay has active-faults at the sea-bed. It has a high possibility to occur earthquakes and Tsunami waves in the case of the huge earthquake, that's why to predict the area of Tsunami run-up is important for decreasing damages to residents by the disaster. However it is very hard task to achieve the simulation by the computer resources problem. A several meter's order of the high resolution calculation is required for the running-up Tsunami simulation because artificial structures on the ground such as roads, buildings, and houses are very small. On the other hand the huge area simulation is also required. In the Toyama-bay case the area is 42 [km] × 15 [km]. When 5 [m] × 5 [m] size computational cells are used for the simulation, over 26,000,000 computational cells are generated. To calculate the simulation, a normal CPU desktop computer took about 10 hours for the calculation. An improvement of calculation time is important problem for the immediate prediction system of Tsunami running-up, as a result it will contribute to protect a lot of residents around the coastal region. The study tried to decrease this calculation time by using multi GPGPU system which is equipped with six NVIDIA TESLA K20xs, InfiniBand network connection between computer nodes by MVAPICH library. As a result 5.16 times faster calculation was achieved on six GPUs than one GPU case and it was 86% parallel efficiency to the linear speed up.

Development of a decision support system for tsunami evacuation: application to the Jiyang District of Sanya city in China

NASA Astrophysics Data System (ADS)

Hou, Jingming; Yuan, Ye; Wang, Peitao; Ren, Zhiyuan; Li, Xiaojuan

2017-03-01

Major tsunami disasters often cause great damage in the first few hours following an earthquake. The possible severity of such events requires preparations to prevent tsunami disasters or mitigate them. This paper is an attempt to develop a decision support system for rapid tsunami evacuation for local decision makers. Based on the numerical results database of tsunami disasters, this system can quickly obtain the tsunami inundation and travel time. Because numerical models are calculated in advance, this system can reduce decision-making time. Population distribution, as a vulnerability factor, was analyzed to identify areas of high risk for tsunami disasters. Combined with spatial data, this system can comprehensively analyze the dynamic and static evacuation process and identify problems that negatively impact evacuation, thus supporting the decision-making for tsunami evacuation in high-risk areas. When an earthquake and tsunami occur, this system can rapidly obtain the tsunami inundation and travel time and provide information to assist with tsunami evacuation operations.

Introduction to "Tsunami Science: Ten Years After the 2004 Indian Ocean Tsunami. Volume I"

NASA Astrophysics Data System (ADS)

Rabinovich, Alexander B.; Geist, Eric L.; Fritz, Hermann M.; Borrero, Jose C.

2015-03-01

Twenty-two papers on the study of tsunamis are included in Volume I of the PAGEOPH topical issue "Tsunami Science: Ten Years after the 2004 Indian Ocean Tsunami." Eight papers examine various aspects of past events with an emphasis on case and regional studies. Five papers are on tsunami warning and forecast, including the improvement of existing tsunami warning systems and the development of new warning systems in the northeast Atlantic and Mediterranean region. Three more papers present the results of analytical studies and discuss benchmark problems. Four papers report the impacts of tsunamis, including the detailed calculation of inundation onshore and into rivers and probabilistic analysis for engineering purposes. The final two papers relate to important investigations of the source and tsunami generation. Overall, the volume not only addresses the pivotal 2004 Indian Ocean (Sumatra) and 2011 Japan (Tohoku) tsunamis, but also examines the tsunami hazard posed to other critical coasts in the world.

Terminator assembly for a floating structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, H.; Hall, J.E.

1987-10-20

A terminator assembly is described for use in mooring a floating surface to the floor of a body of water. The floating structure has has an upper support and a lower support, comprising: a hawsepipe extending downwardly from adjacent the upper support and supported by the lower support, a tension member extending downwardly from adjacent the upper support through the hawsepipe and the lower support. The tension member has a lower end adapted for connection to the floor of the body of water. Locking means connected to an upper portion of the tension member for maintaining the tension member inmore » tension by acting upon an upper portion of the hawsepipe without transferring primary tension load forces to the upper support.« less

Tsunami risk mapping simulation for Malaysia

USGS Publications Warehouse

Teh, S.Y.; Koh, H. L.; Moh, Y.T.; De Angelis, D. L.; Jiang, J.

2011-01-01

The 26 December 2004 Andaman mega tsunami killed about a quarter of a million people worldwide. Since then several significant tsunamis have recurred in this region, including the most recent 25 October 2010 Mentawai tsunami. These tsunamis grimly remind us of the devastating destruction that a tsunami might inflict on the affected coastal communities. There is evidence that tsunamis of similar or higher magnitudes might occur again in the near future in this region. Of particular concern to Malaysia are tsunamigenic earthquakes occurring along the northern part of the Sunda Trench. Further, the Manila Trench in the South China Sea has been identified as another source of potential tsunamigenic earthquakes that might trigger large tsunamis. To protect coastal communities that might be affected by future tsunamis, an effective early warning system must be properly installed and maintained to provide adequate time for residents to be evacuated from risk zones. Affected communities must be prepared and educated in advance regarding tsunami risk zones, evacuation routes as well as an effective evacuation procedure that must be taken during a tsunami occurrence. For these purposes, tsunami risk zones must be identified and classified according to the levels of risk simulated. This paper presents an analysis of tsunami simulations for the South China Sea and the Andaman Sea for the purpose of developing a tsunami risk zone classification map for Malaysia based upon simulated maximum wave heights. ?? 2011 WIT Press.

Tsunami Defense Efforts at Samcheok Port, Korea

NASA Astrophysics Data System (ADS)

Cho, Y. S.

2016-02-01

Tsunamis mainly triggered by impulsive undersea motions are long waves and can propagate a long distance. Thus, they can cause huge casualties not only neighboring countries but also distant countries. Recently, several devastating tsunamis have been occurred around the Pacific Ocean rim. Among them, the Great East Japan tsunami occurred on March 11, 2011 is probably recorded as one of the most destructive tsunamis during last several decades. The Tsunami killed more than 20,000 people (including missing people) and deprived of property damage of approximately 300 billion USD. The eastern coast of the Korean Peninsula has been attacked historically by unexpected tsunami events. These tsunamis were generated by undersea earthquakes occurred off the west coast of Japan. For example, the Central East Sea Tsunami occurred on May 26, 1983 killed 3 people and caused serious property damage at Samcheok Port located at the eastern coast of Korea. Thus, a defense plan against unexpected tsunami strikes is an essential task for the port authority to protect lives of human beings and port facilities. In this study, a master plan of tsunami defense is introduced at Samcheok Port. A tsunami hazard map is also made by employing both propagation and inundation models. Detailed defense efforts are described including the procedure of development of a tsunami hazard map. Keywords: tsunami, hazard map, run-up height, emergency action plan

Hardware math for the 6502 microprocessor

NASA Technical Reports Server (NTRS)

Kissel, R.; Currie, J.

1985-01-01

A floating-point arithmetic unit is described which is being used in the Ground Facility of Large Space Structures Control Verification (GF/LSSCV). The experiment uses two complete inertial measurement units and a set of three gimbal torquers in a closed loop to control the structural vibrations in a flexible test article (beam). A 6502 (8-bit) microprocessor controls four AMD 9511A floating-point arithmetic units to do all the computation in 20 milliseconds.

Free-floating magnetic microstructures by mask photolithography

NASA Astrophysics Data System (ADS)

Huong Au, Thi; Thien Trinh, Duc; Bich Do, Danh; Phu Nguyen, Dang; Cong Tong, Quang; Diep Lai, Ngoc

2018-03-01

This work explores the fabrication of free-floating magnetic structures on a photocurable nanocomposite consisting of superparamagnetic magnetite nanoparticles (Fe3O4) and a commercial SU-8 negative tone photoresist. The nanocomposite was synthesized by mixing magnetic nanoparticles with different kinds of SU-8 resin. We demonstrated that the dispersion of Fe3O4 nanoparticles in nanocomposite solution strongly depended on the particles concentration, the viscosity of SU-8 polymer, and the mixing time. The influence of these factors was demonstrated by examining the structures fabricated by mask photolithography technique. We obtained the best quality of structures at a low concentration, below 5 wt%, of Fe3O4 nanoparticles in SU-8 2005 photoresist for a mixing time of about 20 days. The manipulation of free-floating magnetic microstructures by an external magnetic field was also demonstrated showing promising applications of this magnetic nanocomposite.

Tsunamis: stochastic models of occurrence and generation mechanisms

USGS Publications Warehouse

Geist, Eric L.; Oglesby, David D.

2014-01-01

The devastating consequences of the 2004 Indian Ocean and 2011 Japan tsunamis have led to increased research into many different aspects of the tsunami phenomenon. In this entry, we review research related to the observed complexity and uncertainty associated with tsunami generation, propagation, and occurrence described and analyzed using a variety of stochastic methods. In each case, seismogenic tsunamis are primarily considered. Stochastic models are developed from the physical theories that govern tsunami evolution combined with empirical models fitted to seismic and tsunami observations, as well as tsunami catalogs. These stochastic methods are key to providing probabilistic forecasts and hazard assessments for tsunamis. The stochastic methods described here are similar to those described for earthquakes (Vere-Jones 2013) and volcanoes (Bebbington 2013) in this encyclopedia.

Slip Distribution of the 2011 Tohoku-oki Earthquake obtained by Geodetic and Tsunami Data and with a 3-D Finite Element Model

NASA Astrophysics Data System (ADS)

Romano, F.; Trasatti, E.; Lorito, S.; Ito, Y.; Piatanesi, A.; Lanucara, P.; Hirata, K.; D'Agostino, N.; Cocco, M.

2012-12-01

The rupture process of the Great 2011 Tohoku-oki earthquake has been particularly well studied by using an unprecedented collection of geophysical data. There is a general agreement among the different source models obtained by modeling seismological, geodetic and tsunami data. A slip patch of nearly 40÷50 meters has been imaged and located around and up-dip from the hypocenter by most of published models, while some differences exist in the slip pattern retrieved at shallow depths near the trench, likely due to the different resolving power of distinct data sets and to the adopted fault geometry. It is well known that the modeling of great subduction earthquakes requires the use of 3-D structural models in order to properly account for the effects of topography, bathymetry and the geometrical variations of the plate interface as well as for the effects of elastic contrasts between the subducting plate and the continental lithosphere. In this study we build a 3-D Finite Element (FE) model of the Tohoku-oki area in order to infer the slip distribution of the 2011 earthquake by performing a joint inversion of geodetic (GPS and seafloor observations) and tsunami (ocean bottom pressure sensors, DART and GPS buoys) data. The FE model is used to compute the geodetic and tsunami Green's functions. In order to understand how geometrical and elastic heterogeneities control the inferred slip distribution of the Tohoku-oki earthquake, we compare the slip patterns obtained using both homogeneous and heterogeneous structural models. The goal of this study is to better constrain the slip distribution and the maximum slip amplitudes. In particular, we aim to focus on the rupture process in the shallower part of the fault plane and near the trench, which is crucial to model the tsunami data and to assess the tsunamigenic potential of earthquakes in this region.

2011 Tohoku, Japan tsunami data available from the National Oceanic and Atmospheric Administration/National Geophysical Data Center

NASA Astrophysics Data System (ADS)

Dunbar, P. K.; Mccullough, H. L.; Mungov, G.; Harris, E.

2012-12-01

The U.S. National Oceanic and Atmospheric Administration (NOAA) has primary responsibility for providing tsunami warnings to the Nation, and a leadership role in tsunami observations and research. A key component of this effort is easy access to authoritative data on past tsunamis, a responsibility of the National Geophysical Data Center (NGDC) and collocated World Service for Geophysics. Archive responsibilities include the global historical tsunami database, coastal tide-gauge data from US/NOAA operated stations, the Deep-ocean Assessment and Reporting of Tsunami (DART®) data, damage photos, as well as other related hazards data. Taken together, this integrated archive supports tsunami forecast, warning, research, mitigation and education efforts of NOAA and the Nation. Understanding the severity and timing of tsunami effects is important for tsunami hazard mitigation and warning. The global historical tsunami database includes the date, time, and location of the source event, magnitude of the source, event validity, maximum wave height, the total number of fatalities and dollar damage. The database contains additional information on run-ups (locations where tsunami waves were observed by eyewitnesses, field reconnaissance surveys, tide gauges, or deep ocean sensors). The run-up table includes arrival times, distance from the source, measurement type, maximum wave height, and the number of fatalities and damage for the specific run-up location. Tide gauge data are required for modeling the interaction of tsunami waves with the coast and for verifying propagation and inundation models. NGDC is the long-term archive for all NOAA coastal tide gauge data and is currently archiving 15-second to 1-minute water level data from the NOAA Center for Operational Oceanographic Products and Services (CO-OPS) and the NOAA Tsunami Warning Centers. DART® buoys, which are essential components of tsunami warning systems, are now deployed in all oceans, giving coastal communities faster and more accurate tsunami warnings. NOAA's National Data Buoy Center disseminates real-time DART® data and NGDC processes and archives post-event 15-second high-resolution bottom pressure time series data. An event-specific archive of DART® observations recorded during recent significant tsunamis, including the March 2011 Tohoku, Japan event, are now available through new tsunami event pages integrated with the NGDC global historical tsunami database. These pages are developed to deliver comprehensive summaries of each tsunami event, including socio-economic impacts, tsunami travel time maps, raw observations, de-tided residuals, spectra of the tsunami signal compared to the energy of the background noise, and wavelets. These data are invaluable to tsunami researchers and educators as they are essential to providing a more thorough understanding of tsunamis and their propagation in the open ocean and subsequent inundation of coastal communities. NGDC has collected 289 tide gauge observations, 34 Deep-ocean Assessment and Reporting of Tsunami (DART®) and bottom pressure recorder (BPR) station observations, and over 5,000 eyewitness reports and post-tsunami field survey measurements for the 2011 Tohoku event.

Real-time Tsunami Inundation Prediction Using High Performance Computers

NASA Astrophysics Data System (ADS)

Oishi, Y.; Imamura, F.; Sugawara, D.

2014-12-01

Recently off-shore tsunami observation stations based on cabled ocean bottom pressure gauges are actively being deployed especially in Japan. These cabled systems are designed to provide real-time tsunami data before tsunamis reach coastlines for disaster mitigation purposes. To receive real benefits of these observations, real-time analysis techniques to make an effective use of these data are necessary. A representative study was made by Tsushima et al. (2009) that proposed a method to provide instant tsunami source prediction based on achieving tsunami waveform data. As time passes, the prediction is improved by using updated waveform data. After a tsunami source is predicted, tsunami waveforms are synthesized from pre-computed tsunami Green functions of linear long wave equations. Tsushima et al. (2014) updated the method by combining the tsunami waveform inversion with an instant inversion of coseismic crustal deformation and improved the prediction accuracy and speed in the early stages. For disaster mitigation purposes, real-time predictions of tsunami inundation are also important. In this study, we discuss the possibility of real-time tsunami inundation predictions, which require faster-than-real-time tsunami inundation simulation in addition to instant tsunami source analysis. Although the computational amount is large to solve non-linear shallow water equations for inundation predictions, it has become executable through the recent developments of high performance computing technologies. We conducted parallel computations of tsunami inundation and achieved 6.0 TFLOPS by using 19,000 CPU cores. We employed a leap-frog finite difference method with nested staggered grids of which resolution range from 405 m to 5 m. The resolution ratio of each nested domain was 1/3. Total number of grid points were 13 million, and the time step was 0.1 seconds. Tsunami sources of 2011 Tohoku-oki earthquake were tested. The inundation prediction up to 2 hours after the earthquake occurs took about 2 minutes, which would be sufficient for a practical tsunami inundation predictions. In the presentation, the computational performance of our faster-than-real-time tsunami inundation model will be shown, and preferable tsunami wave source analysis for an accurate inundation prediction will also be discussed.

Bodrum-Kos (Turkey-Greece) Mw 6.6 earthquake and tsunami of 20 July 2017: a test for the Mediterranean tsunami warning system

NASA Astrophysics Data System (ADS)

Heidarzadeh, Mohammad; Necmioglu, Ocal; Ishibe, Takeo; Yalciner, Ahmet C.

2017-12-01

Various Tsunami Service Providers (TSPs) within the Mediterranean Basin supply tsunami warnings including CAT-INGV (Italy), KOERI-RETMC (Turkey), and NOA/HL-NTWC (Greece). The 20 July 2017 Bodrum-Kos (Turkey-Greece) earthquake (Mw 6.6) and tsunami provided an opportunity to assess the response from these TSPs. Although the Bodrum-Kos tsunami was moderate (e.g., runup of 1.9 m) with little damage to properties, it was the first noticeable tsunami in the Mediterranean Basin since the 21 May 2003 western Mediterranean tsunami. Tsunami waveform analysis revealed that the trough-to-crest height was 34.1 cm at the near-field tide gauge station of Bodrum (Turkey). Tsunami period band was 2-30 min with peak periods at 7-13 min. We proposed a source fault model for this tsunami with the length and width of 25 and 15 km and uniform slip of 0.4 m. Tsunami simulations using both nodal planes produced almost same results in terms of agreement between tsunami observations and simulations. Different TSPs provided tsunami warnings at 10 min (CAT-INGV), 19 min (KOERI-RETMC), and 18 min (NOA/HL-NTWC) after the earthquake origin time. Apart from CAT-INGV, whose initial Mw estimation differed 0.2 units with respect to the final value, the response from the other two TSPs came relatively late compared to the desired warning time of 10 min, given the difficulties for timely and accurate calculation of earthquake magnitude and tsunami impact assessment. It is argued that even if a warning time of 10 min was achieved, it might not have been sufficient for addressing near-field tsunami hazards. Despite considerable progress and achievements made within the upstream components of NEAMTWS (North East Atlantic, Mediterranean and Connected seas Tsunami Warning System), the experience from this moderate tsunami may highlight the need for improving operational capabilities of TSPs, but more importantly for effectively integrating civil protection authorities into NEAMTWS and strengthening tsunami education programs.

Seaside, Oregon, Tsunami Vulnerability Assessment Pilot Study

NASA Astrophysics Data System (ADS)

Dunbar, P. K.; Dominey-Howes, D.; Varner, J.

2006-12-01

The results of a pilot study to assess the risk from tsunamis for the Seaside-Gearhart, Oregon region will be presented. To determine the risk from tsunamis, it is first necessary to establish the hazard or probability that a tsunami of a particular magnitude will occur within a certain period of time. Tsunami inundation maps that provide 100-year and 500-year probabilistic tsunami wave height contours for the Seaside-Gearhart, Oregon, region were developed as part of an interagency Tsunami Pilot Study(1). These maps provided the probability of the tsunami hazard. The next step in determining risk is to determine the vulnerability or degree of loss resulting from the occurrence of tsunamis due to exposure and fragility. The tsunami vulnerability assessment methodology used in this study was developed by M. Papathoma and others(2). This model incorporates multiple factors (e.g. parameters related to the natural and built environments and socio-demographics) that contribute to tsunami vulnerability. Data provided with FEMA's HAZUS loss estimation software and Clatsop County, Oregon, tax assessment data were used as input to the model. The results, presented within a geographic information system, reveal the percentage of buildings in need of reinforcement and the population density in different inundation depth zones. These results can be used for tsunami mitigation, local planning, and for determining post-tsunami disaster response by emergency services. (1)Tsunami Pilot Study Working Group, Seaside, Oregon Tsunami Pilot Study--Modernization of FEMA Flood Hazard Maps, Joint NOAA/USGS/FEMA Special Report, U.S. National Oceanic and Atmospheric Administration, U.S. Geological Survey, U.S. Federal Emergency Management Agency, 2006, Final Draft. (2)Papathoma, M., D. Dominey-Howes, D.,Y. Zong, D. Smith, Assessing Tsunami Vulnerability, an example from Herakleio, Crete, Natural Hazards and Earth System Sciences, Vol. 3, 2003, p. 377-389.

The 2017 México Tsunami Record, Numerical Modeling and Threat Assessment in Costa Rica

NASA Astrophysics Data System (ADS)

Chacón-Barrantes, Silvia

2018-03-01

An M w 8.2 earthquake and tsunami occurred offshore the Pacific coast of México on 2017-09-08, at 04:49 UTC. Costa Rican tide gauges have registered a total of 21 local, regional and far-field tsunamis. The Quepos gauge registered 12 tsunamis between 1960 and 2014 before it was relocated inside a harbor by late 2014, where it registered two more tsunamis. This paper analyzes the 2017 México tsunami as recorded by the Quepos gauge. It took 2 h for the tsunami to arrive to Quepos, with a first peak height of 9.35 cm and a maximum amplitude of 18.8 cm occurring about 6 h later. As a decision support tool, this tsunami was modeled for Quepos in real time using ComMIT (Community Model Interface for Tsunami) with the finer grid having a resolution of 1 arcsec ( 30 m). However, the model did not replicate the tsunami record well, probably due to the lack of a finer and more accurate bathymetry. In 2014, the National Tsunami Monitoring System of Costa Rica (SINAMOT) was created, acting as a national tsunami warning center. The occurrence of the 2017 México tsunami raised concerns about warning dissemination mechanisms for most coastal communities in Costa Rica, due to its short travel time.

Mapping coastal marine debris using aerial imagery and spatial analysis.

PubMed

Moy, Kirsten; Neilson, Brian; Chung, Anne; Meadows, Amber; Castrence, Miguel; Ambagis, Stephen; Davidson, Kristine

2017-12-19

This study is the first to systematically quantify, categorize, and map marine macro-debris across the main Hawaiian Islands (MHI), including remote areas (e.g., Niihau, Kahoolawe, and northern Molokai). Aerial surveys were conducted over each island to collect high resolution photos, which were processed into orthorectified imagery and visually analyzed in GIS. The technique provided precise measurements of the quantity, location, type, and size of macro-debris (>0.05m 2 ), identifying 20,658 total debris items. Northeastern (windward) shorelines had the highest density of debris. Plastics, including nets, lines, buoys, floats, and foam, comprised 83% of the total count. In addition, the study located six vessels from the 2011 Tōhoku tsunami. These results created a baseline of the location, distribution, and composition of marine macro-debris across the MHI. Resource managers and communities may target high priority areas, particularly along remote coastlines where macro-debris counts were largely undocumented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quality Improvement: Creating a Float Pool Specialty Within a New Graduate Residency.

PubMed

Shinners, Jean; Alejandro, John Aldrich N; Frigillana, Vanessa; Desmond, Juliann; LaVigne, Ronda

2016-01-01

Creating new norms is essential for success as acute care leaders seek to redesign care delivery. Through the structures of the registered nurse (RN) residency and utilizing a quality improvement process, new graduate RNs demonstrated success in creating a centralized float pool resource.

Uncertainty in tsunami sediment transport modeling

USGS Publications Warehouse

Jaffe, Bruce E.; Goto, Kazuhisa; Sugawara, Daisuke; Gelfenbaum, Guy R.; La Selle, SeanPaul M.

2016-01-01

Erosion and deposition from tsunamis record information about tsunami hydrodynamics and size that can be interpreted to improve tsunami hazard assessment. We explore sources and methods for quantifying uncertainty in tsunami sediment transport modeling. Uncertainty varies with tsunami, study site, available input data, sediment grain size, and model. Although uncertainty has the potential to be large, published case studies indicate that both forward and inverse tsunami sediment transport models perform well enough to be useful for deciphering tsunami characteristics, including size, from deposits. New techniques for quantifying uncertainty, such as Ensemble Kalman Filtering inversion, and more rigorous reporting of uncertainties will advance the science of tsunami sediment transport modeling. Uncertainty may be decreased with additional laboratory studies that increase our understanding of the semi-empirical parameters and physics of tsunami sediment transport, standardized benchmark tests to assess model performance, and development of hybrid modeling approaches to exploit the strengths of forward and inverse models.

Tsunami Preparedness in Washington (video)

USGS Publications Warehouse

Loeffler, Kurt; Gesell, Justine

2010-01-01

Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the West coast of the United States, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training. This video about tsunami preparedness in Washington distinguishes between a local tsunami and a distant event and focus on the specific needs of this region. It offers guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings, who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis. This video was produced by the US Geological Survey (USGS) in cooperation with Washington Emergency Management Division (EMD) and with funding by the National Tsunami Hazard Mitigation Program.

Science and Engineering of an Operational Tsunami Forecasting System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez, Frank

2009-04-06

After a review of tsunami statistics and the destruction caused by tsunamis, a means of forecasting tsunamis is discussed as part of an overall program of reducing fatalities through hazard assessment, education, training, mitigation, and a tsunami warning system. The forecast is accomplished via a concept called Deep Ocean Assessment and Reporting of Tsunamis (DART). Small changes of pressure at the sea floor are measured and relayed to warning centers. Under development is an international modeling network to transfer, maintain, and improve tsunami forecast models.

Science and Engineering of an Operational Tsunami Forecasting System

ScienceCinema

Gonzalez, Frank

2017-12-09

After a review of tsunami statistics and the destruction caused by tsunamis, a means of forecasting tsunamis is discussed as part of an overall program of reducing fatalities through hazard assessment, education, training, mitigation, and a tsunami warning system. The forecast is accomplished via a concept called Deep Ocean Assessment and Reporting of Tsunamis (DART). Small changes of pressure at the sea floor are measured and relayed to warning centers. Under development is an international modeling network to transfer, maintain, and improve tsunami forecast models.

Hydraulic experiment on tsunami sand deposits relating with grain size distribution and magnitude of incident waves

NASA Astrophysics Data System (ADS)

Yamamoto, A.; Takahashi, T.; Harada, K.; Nojima, K.

2016-12-01

A huge earthquake occurred off the Tohoku district in Japan on March 11th, 2011. A massive tsunami generated by the earthquake attacked coastal areas and caused serious damage. The tsunami disaster requires to reconsider tsunami measures in the Nankai Trough. Many of the measures are based on histories of large earthquakes and tsunamis. Because they are low frequency disasters and their historical documents are limited, tsunami sand deposits have been expected to analyze paleotsunamis. Tsunami sand deposits, however, are only used to confirm the fact of tsunamis and to determine the relative magnitudes. The thickness of sand layer and the grain size may be clues to estimate the tsunami force. Further, it could reveal the tsunami source. These results are also useful to improve the present tsunami measures. The objective of this study is to investigate the formation mechanism of tsunami sand deposits by hydraulic experiment. A two-dimensional water channel consisted of a wave maker, a flat section and a slope section. A movable bed section with various grain sizes and distribution of sand was set at the end of flat section. Bore waves of several heights transported the sand to the slope section by run-up. Water surface elevation and velocity were measured at several points. Tsunami sand deposit distribution was also measured along the slope section. The experimental result showed that the amount of tsunami sand deposit was relating with the grain size distribution and the magnitude of incident waves. Further, the number of incident waves affected the profile of tsunami sand deposits.

Tsunami Hazard Assessment: Source regions of concern to U.S. interests derived from NOAA Tsunami Forecast Model Development

NASA Astrophysics Data System (ADS)

Eble, M. C.; uslu, B. U.; Wright, L.

2013-12-01

Synthetic tsunamis generated from source regions around the Pacific Basin are analyzed in terms of their relative impact on United States coastal locations.. The region of tsunami origin is as important as the expected magnitude and the predicted inundation for understanding tsunami hazard. The NOAA Center for Tsunami Research has developed high-resolution tsunami models capable of predicting tsunami arrival time and amplitude of waves at each location. These models have been used to conduct tsunami hazard assessments to assess maximum impact and tsunami inundation for use by local communities in education and evacuation map development. Hazard assessment studies conducted for Los Angeles, San Francisco, Crescent City, Hilo, and Apra Harbor are combined with results of tsunami forecast model development at each of seventy-five locations. Complete hazard assessment, identifies every possible tsunami variation from a pre-computed propagation database. Study results indicate that the Eastern Aleutian Islands and Alaska are the most likely regions to produce the largest impact on the West Coast of the United States, while the East Philippines and Mariana trench regions impact Apra Harbor, Guam. Hawaii appears to be impacted equally from South America, Alaska and the Kuril Islands.

Field survey of the 1 April 2014 Iquique tsunami along the coasts of Chile and Peru

NASA Astrophysics Data System (ADS)

Lagos, M.; Fritz, H. M.

2014-12-01

On 1 April, 2014 a magnitude Mw 8.2 earthquake occurred off the coast of northern Chile less than 100 km NW of Iquique within a region of historic quiescence termed the northern Chile seismic gap. The ensuing tsunami inundation caused mostly minor damage centered in Iquique and neighbouring stretches of coastline. Fortunately, ancestral knowledge from the past 1868 and 1877 tsunamis in the region along with the recent 2010 Maule tsunami, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were no tsunami victims, while a handful of fatalities were associated to the earthquake and the tsunami evacuation. The local scientist deployed in the morning hours to start the tsunami survey in Iquique on the day after the earthquake. The international scientist joined the local effort from April 6 to 11. The international tsunami survey team (ITST) documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 700 km stretch of coastline from the Mejillones Peninsula (23.5° S) north of Antofagasta in Chile up to Vila Vila (18.1° S) in southern Peru. We surveyed 30 locations with differential GPS and laser range finders. The tsunami impact peaked in the vicinity of Iquique exceeding 4 m in tsunami height. A significant variation in tsunami impact was observed along the coastlines of Chile and Peru both at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2014 Chile tsunami are compared against the 1868, 1877 and 2010 Chile tsunamis. Given the magnitude of the 1 April 2014 earthquake the tsunami could have been significantly larger. However the absence of a massive tsunami may mislead residents in the future to believe another minor tsunami may be generated after an earthquake of similar magnitude. Hence the April fool's day event poses significant challenges to community-based education. The team interviewed numerous eyewitnesses and educated residents about tsunami hazards since awareness programs are essential to save lives in locales at risk from locally generated tsunamis.

A Global Sensitivity Analysis Method on Maximum Tsunami Wave Heights to Potential Seismic Source Parameters

NASA Astrophysics Data System (ADS)

Ren, Luchuan

2015-04-01

A Global Sensitivity Analysis Method on Maximum Tsunami Wave Heights to Potential Seismic Source Parameters Luchuan Ren, Jianwei Tian, Mingli Hong Institute of Disaster Prevention, Sanhe, Heibei Province, 065201, P.R. China It is obvious that the uncertainties of the maximum tsunami wave heights in offshore area are partly from uncertainties of the potential seismic tsunami source parameters. A global sensitivity analysis method on the maximum tsunami wave heights to the potential seismic source parameters is put forward in this paper. The tsunami wave heights are calculated by COMCOT ( the Cornell Multi-grid Coupled Tsunami Model), on the assumption that an earthquake with magnitude MW8.0 occurred at the northern fault segment along the Manila Trench and triggered a tsunami in the South China Sea. We select the simulated results of maximum tsunami wave heights at specific sites in offshore area to verify the validity of the method proposed in this paper. For ranking importance order of the uncertainties of potential seismic source parameters (the earthquake's magnitude, the focal depth, the strike angle, dip angle and slip angle etc..) in generating uncertainties of the maximum tsunami wave heights, we chose Morris method to analyze the sensitivity of the maximum tsunami wave heights to the aforementioned parameters, and give several qualitative descriptions of nonlinear or linear effects of them on the maximum tsunami wave heights. We quantitatively analyze the sensitivity of the maximum tsunami wave heights to these parameters and the interaction effects among these parameters on the maximum tsunami wave heights by means of the extended FAST method afterward. The results shows that the maximum tsunami wave heights are very sensitive to the earthquake magnitude, followed successively by the epicenter location, the strike angle and dip angle, the interactions effect between the sensitive parameters are very obvious at specific site in offshore area, and there exist differences in importance order in generating uncertainties of the maximum tsunami wave heights for same group parameters at different specific sites in offshore area. These results are helpful to deeply understand the relationship between the tsunami wave heights and the seismic tsunami source parameters. Keywords: Global sensitivity analysis; Tsunami wave height; Potential seismic tsunami source parameter; Morris method; Extended FAST method

Rapid Determination of Appropriate Source Models for Tsunami Early Warning using a Depth Dependent Rigidity Curve: Method and Numerical Tests

NASA Astrophysics Data System (ADS)

Tanioka, Y.; Miranda, G. J. A.; Gusman, A. R.

2017-12-01

Recently, tsunami early warning technique has been improved using tsunami waveforms observed at the ocean bottom pressure gauges such as NOAA DART system or DONET and S-NET systems in Japan. However, for tsunami early warning of near field tsunamis, it is essential to determine appropriate source models using seismological analysis before large tsunamis hit the coast, especially for tsunami earthquakes which generated significantly large tsunamis. In this paper, we develop a technique to determine appropriate source models from which appropriate tsunami inundation along the coast can be numerically computed The technique is tested for four large earthquakes, the 1992 Nicaragua tsunami earthquake (Mw7.7), the 2001 El Salvador earthquake (Mw7.7), the 2004 El Astillero earthquake (Mw7.0), and the 2012 El Salvador-Nicaragua earthquake (Mw7.3), which occurred off Central America. In this study, fault parameters were estimated from the W-phase inversion, then the fault length and width were determined from scaling relationships. At first, the slip amount was calculated from the seismic moment with a constant rigidity of 3.5 x 10**10N/m2. The tsunami numerical simulation was carried out and compared with the observed tsunami. For the 1992 Nicaragua tsunami earthquake, the computed tsunami was much smaller than the observed one. For the 2004 El Astillero earthquake, the computed tsunami was overestimated. In order to solve this problem, we constructed a depth dependent rigidity curve, similar to suggested by Bilek and Lay (1999). The curve with a central depth estimated by the W-phase inversion was used to calculate the slip amount of the fault model. Using those new slip amounts, tsunami numerical simulation was carried out again. Then, the observed tsunami heights, run-up heights, and inundation areas for the 1992 Nicaragua tsunami earthquake were well explained by the computed one. The other tsunamis from the other three earthquakes were also reasonably well explained by the computed ones. Therefore, our technique using a depth dependent rigidity curve is worked to estimate an appropriate fault model which reproduces tsunami heights near the coast in Central America. The technique may be worked in the other subduction zones by finding a depth dependent rigidity curve in that particular subduction zone.

Offshore Evidence for an Undocumented Tsunami Event in the ‘Low Risk’ Gulf of Aqaba-Eilat, Northern Red Sea

PubMed Central

Goodman Tchernov, Beverly; Katz, Timor; Shaked, Yonathan; Qupty, Nairooz; Kanari, Mor; Niemi, Tina; Agnon, Amotz

2016-01-01

Although the Gulf of Aqaba-Eilat is located in the tectonically active northern Red Sea, it has been described as low-risk with regard to tsunami activity because there are no modern records of damaging tsunami events and only one tsunami (1068 AD) referred to in historical records. However, this assessment may be poorly informed given that the area was formed by and is located along the seismically active Dead Sea Fault, its population is known to fluctuate in size and literacy in part due to its harsh hyper-arid climate, and there is a dearth of field studies addressing the presence or absence of tsunamigenic deposits. Here we show evidence from two offshore cores for a major paleotsunami that occurred ~2300 years ago with a sedimentological footprint that far exceeds the scarce markers of the historically mentioned 1068 AD event. The interpretation is based on the presence of a laterally continuous and synchronous, anomalous sedimentological deposit that includes allochtonous inclusions and unique structural characteristics. Based on sedimentological parameters, these deposits could not be accounted for by other transport events, or other known background sedimentological processes. PMID:26815553

Offshore Evidence for an Undocumented Tsunami Event in the 'Low Risk' Gulf of Aqaba-Eilat, Northern Red Sea.

PubMed

Goodman Tchernov, Beverly; Katz, Timor; Shaked, Yonathan; Qupty, Nairooz; Kanari, Mor; Niemi, Tina; Agnon, Amotz

2016-01-01

Although the Gulf of Aqaba-Eilat is located in the tectonically active northern Red Sea, it has been described as low-risk with regard to tsunami activity because there are no modern records of damaging tsunami events and only one tsunami (1068 AD) referred to in historical records. However, this assessment may be poorly informed given that the area was formed by and is located along the seismically active Dead Sea Fault, its population is known to fluctuate in size and literacy in part due to its harsh hyper-arid climate, and there is a dearth of field studies addressing the presence or absence of tsunamigenic deposits. Here we show evidence from two offshore cores for a major paleotsunami that occurred ~2300 years ago with a sedimentological footprint that far exceeds the scarce markers of the historically mentioned 1068 AD event. The interpretation is based on the presence of a laterally continuous and synchronous, anomalous sedimentological deposit that includes allochtonous inclusions and unique structural characteristics. Based on sedimentological parameters, these deposits could not be accounted for by other transport events, or other known background sedimentological processes.

Simulation of landslide and tsunami of the 1741 Oshima-Oshima eruption in Hokkaido, Japan

NASA Astrophysics Data System (ADS)

Ioki, K.; Yanagisawa, H.; Tanioka, Y.; Kawakami, G.; Kase, Y.; Nishina, K.; Hirose, W.; Ishimaru, S.

2017-12-01

The 1741 tsunami was generated by the Oshima-Oshima sector collapse in the southwestern Hokkaido, Japan. The tsunami caused great damage along the coast of Japan Sea in Oshima and Tsugaru peninsula and was the largest scale generated in the Japan sea. By the survey of tsunami deposits, at the coast of Okushiri Island and Hiyama in Hokkaido, tsunami deposits of this tsunami were found. In this study, the landslide and tsunami by the Oshima-Oshima eruption were modeled to explain distribution of debris deposits, tsunami heights by historical records, and distribution of tsunami deposits. First, region of landslide and debris deposits were made out from the bathymetry based on the bathymetry survey data (Satake and Kato, 2001) in the north slope of Oshima-Oshima. In addition, topography before the sector collapse and landslide volume were re-estimated. The volume of landslide was estimated at 2.2 km3. Based on those data, the landslide and tsunami were simulated using two-layer model considered soil mass and water mass. The model was made improvements the integrated model of landslide and tsunami (Yanagisawa et al., 2014). The angle of internal friction was calculated 4 cases, included the bottom friction term in soil mass, to affect the movement of landslide. The Manning's roughness coefficient was calculated 5 cases, included the bottom friction term in soil mass, to affect the generation of tsunami. By the parameter study, optimal solutions were found. As the results, soil mass slid slowly submarine slope and stopped after about 15 minutes. Distribution of computed debris deposits agree relatively well with region of debris deposits made out from the bathymetry. On the other hand, the first wave of tsunami was generated during 1 minute that soil mass was sliding. Calculated tsunami heights match with historical records along the coast of Okushiri and Hiyama in Hokkaido. Calculated inundation area of tsunami cover distribution of tsunami deposits found by tsunami deposits survey in Okushiri and Hiyama coast.

Highly variable recurrence of tsunamis in the 7,400 years before the 2004 Indian Ocean tsunami

NASA Astrophysics Data System (ADS)

Horton, B.; Rubin, C. M.; Sieh, K.; Jessica, P.; Daly, P.; Ismail, N.; Parnell, A. C.

2017-12-01

The devastating 2004 Indian Ocean tsunami caught millions of coastal residents and the scientific community off-guard. Subsequent research in the Indian Ocean basin has identified prehistoric tsunamis, but the timing and recurrence intervals of such events are uncertain. Here, we identify coastal caves as a new depositional environment for reconstructing tsunami records and present a 5,000 year record of continuous tsunami deposits from a coastal cave in Sumatra, Indonesia which shows the irregular recurrence of 11 tsunamis between 7,400 and 2,900 years BP. The data demonstrates that the 2004 tsunami was just the latest in a sequence of devastating tsunamis stretching back to at least the early Holocene and suggests a high likelihood for future tsunamis in the Indian Ocean. The sedimentary record in the cave shows that ruptures of the Sunda megathrust vary between large (which generated the 2004 Indian Ocean tsunami) and smaller slip failures. The chronology of events suggests the recurrence of multiple smaller tsunamis within relatively short time periods, interrupted by long periods of strain accumulation followed by giant tsunamis. The average time period between tsunamis is about 450 years with intervals ranging from a long, dormant period of over 2,000 years, to multiple tsunamis within the span of a century. The very long dormant period suggests that the Sunda megathrust is capable of accumulating large slip deficits between earthquakes. Such a high slip rupture would produce a substantially larger earthquake than the 2004 event. Although there is evidence that the likelihood of another tsunamigenic earthquake in Aceh province is high, these variable recurrence intervals suggest that long dormant periods may follow Sunda Megathrust ruptures as large as that of 2004 Indian Ocean tsunami. The remarkable variability of recurrence suggests that regional hazard mitigation plans should be based upon the high likelihood of future destructive tsunami demonstrated by the cave record and other paleotsunami sites, rather than estimates of recurrence intervals.

Role of sediment transport model to improve the tsunami numerical simulation

NASA Astrophysics Data System (ADS)

Sugawara, D.; Yamashita, K.; Takahashi, T.; Imamura, F.

2015-12-01

Are we overlooking an important factor for improved numerical prediction of tsunamis in shallow sea to onshore? In this presentation, several case studies on numerical modeling of tsunami-induced sediment transport are reviewed, and the role of sediment transport models for tsunami inundation simulation is discussed. Large-scale sediment transport and resulting geomorphological change occurred in the coastal areas of Tohoku, Japan, due to the 2011 Tohoku Earthquake Tsunami. Datasets obtained after the tsunami, including geomorphological and sedimentological data as well as hydrodynamic records, allows us to validate the numerical model in detail. The numerical modeling of the sediment transport by the 2011 tsunami depicted the severest erosion of sandy beach, as well as characteristic spatial patterns of erosion and deposition on the seafloor, which have taken place in Hirota Bay, Sanriku Coast. Quantitative comparisons of observation and simulation of the geomorphological changes in Sanriku Coast and Sendai Bay showed that the numerical model can predict the volumes of erosion and deposition with a right order. In addition, comparison of the simulation with aerial video footages demonstrated the numerical model is capable of tracking the overall processes of tsunami sediment transport. Although tsunami-induced sediment erosion and deposition sometimes cause significant geomorphological change, and may enhance tsunami hydrodynamic impact to the coastal zones, most tsunami simulations do not include sediment transport modeling. A coupled modeling of tsunami hydrodynamics and sediment transport draws a different picture of tsunami hazard, comparing with simple hydrodynamic modeling of tsunami inundation. Since tsunami-induced erosion, deposition and geomorphological change sometimes extend more than several kilometers across the coastline, two-dimensional horizontal model are typically used for the computation of tsunami hydrodynamics and sediment transport. Limitations of the conventional model and future challenges are discussed regarding further improvement of numerical modeling of tsunami and sediment transport. Improved numerical modeling may provide useful information for assessing sediment-related damages and planning post-disaster recovery.

A Hybrid Tsunami Risk Model for Japan

NASA Astrophysics Data System (ADS)

Haseemkunju, A. V.; Smith, D. F.; Khater, M.; Khemici, O.; Betov, B.; Scott, J.

2014-12-01

Around the margins of the Pacific Ocean, denser oceanic plates slipping under continental plates cause subduction earthquakes generating large tsunami waves. The subducting Pacific and Philippine Sea plates create damaging interplate earthquakes followed by huge tsunami waves. It was a rupture of the Japan Trench subduction zone (JTSZ) and the resultant M9.0 Tohoku-Oki earthquake that caused the unprecedented tsunami along the Pacific coast of Japan on March 11, 2011. EQECAT's Japan Earthquake model is a fully probabilistic model which includes a seismo-tectonic model describing the geometries, magnitudes, and frequencies of all potential earthquake events; a ground motion model; and a tsunami model. Within the much larger set of all modeled earthquake events, fault rupture parameters for about 24000 stochastic and 25 historical tsunamigenic earthquake events are defined to simulate tsunami footprints using the numerical tsunami model COMCOT. A hybrid approach using COMCOT simulated tsunami waves is used to generate inundation footprints, including the impact of tides and flood defenses. Modeled tsunami waves of major historical events are validated against observed data. Modeled tsunami flood depths on 30 m grids together with tsunami vulnerability and financial models are then used to estimate insured loss in Japan from the 2011 tsunami. The primary direct report of damage from the 2011 tsunami is in terms of the number of buildings damaged by municipality in the tsunami affected area. Modeled loss in Japan from the 2011 tsunami is proportional to the number of buildings damaged. A 1000-year return period map of tsunami waves shows high hazard along the west coast of southern Honshu, on the Pacific coast of Shikoku, and on the east coast of Kyushu, primarily associated with major earthquake events on the Nankai Trough subduction zone (NTSZ). The highest tsunami hazard of more than 20m is seen on the Sanriku coast in northern Honshu, associated with the JTSZ.

Uncertainty in the Modeling of Tsunami Sediment Transport

NASA Astrophysics Data System (ADS)

Jaffe, B. E.; Sugawara, D.; Goto, K.; Gelfenbaum, G. R.; La Selle, S.

2016-12-01

Erosion and deposition from tsunamis record information about tsunami hydrodynamics and size that can be interpreted to improve tsunami hazard assessment. A recent study (Jaffe et al., 2016) explores sources and methods for quantifying uncertainty in tsunami sediment transport modeling. Uncertainty varies with tsunami properties, study site characteristics, available input data, sediment grain size, and the model used. Although uncertainty has the potential to be large, case studies for both forward and inverse models have shown that sediment transport modeling provides useful information on tsunami inundation and hydrodynamics that can be used to improve tsunami hazard assessment. New techniques for quantifying uncertainty, such as Ensemble Kalman Filtering inversion, and more rigorous reporting of uncertainties will advance the science of tsunami sediment transport modeling. Uncertainty may be decreased with additional laboratory studies that increase our understanding of the semi-empirical parameters and physics of tsunami sediment transport, standardized benchmark tests to assess model performance, and the development of hybrid modeling approaches to exploit the strengths of forward and inverse models. As uncertainty in tsunami sediment transport modeling is reduced, and with increased ability to quantify uncertainty, the geologic record of tsunamis will become more valuable in the assessment of tsunami hazard. Jaffe, B., Goto, K., Sugawara, D., Gelfenbaum, G., and La Selle, S., "Uncertainty in Tsunami Sediment Transport Modeling", Journal of Disaster Research Vol. 11 No. 4, pp. 647-661, 2016, doi: 10.20965/jdr.2016.p0647 https://www.fujipress.jp/jdr/dr/dsstr001100040647/

Introduction to "Global Tsunami Science: Past and Future, Volume III"

NASA Astrophysics Data System (ADS)

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2018-04-01

Twenty papers on the study of tsunamis are included in Volume III of the PAGEOPH topical issue "Global Tsunami Science: Past and Future". Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 and Volume II as PAGEOPH, vol. 174, No. 8, 2017. Two papers in Volume III focus on specific details of the 2009 Samoa and the 1923 northern Kamchatka tsunamis; they are followed by three papers related to tsunami hazard assessment for three different regions of the world oceans: South Africa, Pacific coast of Mexico and the northwestern part of the Indian Ocean. The next six papers are on various aspects of tsunami hydrodynamics and numerical modelling, including tsunami edge waves, resonant behaviour of compressible water layer during tsunamigenic earthquakes, dispersive properties of seismic and volcanically generated tsunami waves, tsunami runup on a vertical wall and influence of earthquake rupture velocity on maximum tsunami runup. Four papers discuss problems of tsunami warning and real-time forecasting for Central America, the Mediterranean coast of France, the coast of Peru, and some general problems regarding the optimum use of the DART buoy network for effective real-time tsunami warning in the Pacific Ocean. Two papers describe historical and paleotsunami studies in the Russian Far East. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: asteroid airburst and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Introduction to “Global tsunami science: Past and future, Volume III”

USGS Publications Warehouse

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2018-01-01

Twenty papers on the study of tsunamis are included in Volume III of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 and Volume II as PAGEOPH, vol. 174, No. 8, 2017. Two papers in Volume III focus on specific details of the 2009 Samoa and the 1923 northern Kamchatka tsunamis; they are followed by three papers related to tsunami hazard assessment for three different regions of the world oceans: South Africa, Pacific coast of Mexico and the northwestern part of the Indian Ocean. The next six papers are on various aspects of tsunami hydrodynamics and numerical modelling, including tsunami edge waves, resonant behaviour of compressible water layer during tsunamigenic earthquakes, dispersive properties of seismic and volcanically generated tsunami waves, tsunami runup on a vertical wall and influence of earthquake rupture velocity on maximum tsunami runup. Four papers discuss problems of tsunami warning and real-time forecasting for Central America, the Mediterranean coast of France, the coast of Peru, and some general problems regarding the optimum use of the DART buoy network for effective real-time tsunami warning in the Pacific Ocean. Two papers describe historical and paleotsunami studies in the Russian Far East. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: asteroid airburst and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Forecasting database for the tsunami warning regional center for the western Mediterranean Sea

NASA Astrophysics Data System (ADS)

Gailler, A.; Hebert, H.; Loevenbruck, A.; Hernandez, B.

2010-12-01

Improvements in the availability of sea-level observations and advances in numerical modeling techniques are increasing the potential for tsunami warnings to be based on numerical model forecasts. Numerical tsunami propagation and inundation models are well developed, but they present a challenge to run in real-time, partly due to computational limitations and also to a lack of detailed knowledge on the earthquake rupture parameters. Through the establishment of the tsunami warning regional center for NE Atlantic and western Mediterranean Sea, the CEA is especially in charge of providing rapidly a map with uncertainties showing zones in the main axis of energy at the Mediterranean scale. The strategy is based initially on a pre-computed tsunami scenarios database, as source parameters available a short time after an earthquake occurs are preliminary and may be somewhat inaccurate. Existing numerical models are good enough to provide a useful guidance for warning structures to be quickly disseminated. When an event will occur, an appropriate variety of offshore tsunami propagation scenarios by combining pre-computed propagation solutions (single or multi sources) may be recalled through an automatic interface. This approach would provide quick estimates of tsunami offshore propagation, and aid hazard assessment and evacuation decision-making. As numerical model accuracy is inherently limited by errors in bathymetry and topography, and as inundation maps calculation is more complex and expensive in term of computational time, only tsunami offshore propagation modeling will be included in the forecasting database using a single sparse bathymetric computation grid for the numerical modeling. Because of too much variability in the mechanism of tsunamigenic earthquakes, all possible magnitudes cannot be represented in the scenarios database. In principle, an infinite number of tsunami propagation scenarios can be constructed by linear combinations of a finite number of pre-computed unit scenarios. The whole notion of a pre-computed forecasting database also requires a historical earthquake and tsunami database, as well as an up-to-date seismotectonic database including faults geometry and a zonation based on seismotectonic synthesis of source zones and tsunamigenic faults. Our forecast strategy is thus based on a unit source function methodology, whereby the model runs are combined and scaled linearly to produce any composite tsunamis propagation solution. Each unit source function is equivalent to a tsunami generated by a Mo 1.75E+19 N.m earthquake (Mw ~6.8) with a rectangular fault 25 km by 20 km in size and 1 m in slip. The faults of the unit functions are placed adjacent to each other, following the discretization of the main seismogenic faults bounding the western Mediterranean basin. The number of unit functions involved varies with the magnitude of the wanted composite solution and the combined waveheights are multiplied by a given scaling factor to produce the new arbitrary scenario. Some test-cases examples are presented (e.g., Boumerdès 2003 [Algeria, Mw 6.8], Djijel 1856 [Algeria, Mw 7.2], Ligure 1887 [Italia, Mw 6.5-6.7]).

Air-Deployable Profiling Floats for Tropical Cyclone Research

NASA Astrophysics Data System (ADS)

Jayne, S. R.; Robbins, P.; Owens, B.; Ekholm, A.; Dufour, J. E.; Sanabia, E.

2016-02-01

The development of a smaller profiling float that can be launched from Hurricane Hunter aircraft offers the opportunity to monitor the upper-ocean thermal structure over a time span of many months. These Argo-type profiling floats can be deployed in advance of, or during, a tropical cyclone from any aircraft equipped with an A-sized (AXBT) launch tube, or from the stern ramp of a C-130. The floats have the same dimensions as an AXBT and weigh about 8.5 kg. Upon deployment, the floats parachute to the surface, detach and automatically begin their programmed mission. The recorded temperature data is averaged over 1-meter bins that are reported back via the Iridium satellite phone network, which is then automatically processed and posted to the GTS. The floats are also reprogrammable via the 2-way communication afforded by Iridium. We report on the results of deployments during the 2014 and 2015 hurricane seasons. Unique observations of the ocean response from Hurricane Ignacio are particularly noteworthy and will be presented. Further plans for continued development of floats include measuring salinity (from an inductive conductivity sensor) and observations of the surface wave field (measured by an onboard accelerometer) will also be described.

Field survey of the 16 September 2015 Chile tsunami

NASA Astrophysics Data System (ADS)

Lagos, Marcelo; Fritz, Hermann M.

2016-04-01

On the evening of 16 September, 2015 a magnitude Mw 8.3 earthquake occurred off the coast of central Chile's Coquimbo region. The ensuing tsunami caused significant inundation and damage in the Coquimbo or 4th region and mostly minor effects in neighbouring 3rd and 5th regions. Fortunately, ancestral knowledge from the past 1922 and 1943 tsunamis in the region along with the catastrophic 2010 Maule and recent 2014 tsunamis, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were a few tsunami victims; while a handful of fatalities were associated to earthquake induced building collapses and the physical stress of tsunami evacuation. The international scientist joined the local effort from September 20 to 26, 2015. The international tsunami survey team (ITST) interviewed numerous eyewitnesses and documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 500 km stretch of coastline from Caleta Chañaral de Aceituno (28.8° S) south of Huasco down to Llolleo near San Antonio (33.6° S). We surveyed more than 40 locations and recorded more than 100 tsunami and runup heights with differential GPS and integrated laser range finders. The tsunami impact peaked at Caleta Totoral near Punta Aldea with both tsunami and runup heights exceeding 10 m as surveyed on September 22 and broadcasted nationwide that evening. Runup exceeded 10 m at a second uninhabited location some 15 km south of Caleta Totoral. A significant variation in tsunami impact was observed along the coastlines of central Chile at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2015 Chile tsunami are compared against the 1922, 1943, 2010 and 2014 Chile tsunamis. The tsunami was characterized by rapid arrival within minutes in the nearfield requiring spontaneous self-evacuation as warning messages did not reach some of the hardest hit fishing villages prior to tsunami arrival. The absence of a massive tsunami outside of the 4th region may mislead evacuated residents in the adjacent 3rd and 5th regions of Chile in potential future events. This event poses significant challenges to community-based education raising tsunami awareness. The team educated residents about tsunami hazards since awareness programs are essential to save lives in locales at risk from near-field tsunamis.

Evolution of tsunami warning systems and products.

PubMed

Bernard, Eddie; Titov, Vasily

2015-10-28

Each year, about 60 000 people and $4 billion (US$) in assets are exposed to the global tsunami hazard. Accurate and reliable tsunami warning systems have been shown to provide a significant defence for this flooding hazard. However, the evolution of warning systems has been influenced by two processes: deadly tsunamis and available technology. In this paper, we explore the evolution of science and technology used in tsunami warning systems, the evolution of their products using warning technologies, and offer suggestions for a new generation of warning products, aimed at the flooding nature of the hazard, to reduce future tsunami impacts on society. We conclude that coastal communities would be well served by receiving three standardized, accurate, real-time tsunami warning products, namely (i) tsunami energy estimate, (ii) flooding maps and (iii) tsunami-induced harbour current maps to minimize the impact of tsunamis. Such information would arm communities with vital flooding guidance for evacuations and port operations. The advantage of global standardized flooding products delivered in a common format is efficiency and accuracy, which leads to effectiveness in promoting tsunami resilience at the community level. © 2015 The Authors.

Evolution of tsunami warning systems and products

PubMed Central

Bernard, Eddie; Titov, Vasily

2015-01-01

Each year, about 60 000 people and $4 billion (US$) in assets are exposed to the global tsunami hazard. Accurate and reliable tsunami warning systems have been shown to provide a significant defence for this flooding hazard. However, the evolution of warning systems has been influenced by two processes: deadly tsunamis and available technology. In this paper, we explore the evolution of science and technology used in tsunami warning systems, the evolution of their products using warning technologies, and offer suggestions for a new generation of warning products, aimed at the flooding nature of the hazard, to reduce future tsunami impacts on society. We conclude that coastal communities would be well served by receiving three standardized, accurate, real-time tsunami warning products, namely (i) tsunami energy estimate, (ii) flooding maps and (iii) tsunami-induced harbour current maps to minimize the impact of tsunamis. Such information would arm communities with vital flooding guidance for evacuations and port operations. The advantage of global standardized flooding products delivered in a common format is efficiency and accuracy, which leads to effectiveness in promoting tsunami resilience at the community level. PMID:26392620

Tsunami hazard assessment in the southern Colombian Pacific basin and a proposal to regenerate a previous barrier island as protection

NASA Astrophysics Data System (ADS)

Otero, L. J.; Restrepo, J. C.; Gonzalez, M.

2014-05-01

In this study, the tsunami hazard posed to 120 000 inhabitants of Tumaco (Colombia) is assessed, and an evaluation and analysis of regenerating the previous El Guano Island for tsunami protection is conducted. El Guano Island was a sandy barrier island in front of the city of Tumaco until its disappearance during the tsunami of 1979; the island is believed to have played a protective role, substantially reducing the scale of the disaster. The analysis is conducted by identifying seismotectonic parameters and focal mechanisms of tsunami generation in the area, determining seven potential generation sources, applying a numerical model for tsunami generation and propagation, and evaluating the effect of tsunamis on Tumaco. The results show that in the current situation, this area is vulnerable to impact and flooding by tsunamis originating nearby. El Guano Island was found to markedly reduce flood levels and the energy flux of tsunami waves in Tumaco during the 1979 tsunami. By reducing the risk of flooding due to tsunamis, the regeneration and morphological modification of El Guano Island would help to protect Tumaco.

Tsunami hazard assessment in the southern Colombian Pacific Basin and a proposal to regenerate a previous barrier island as protection

NASA Astrophysics Data System (ADS)

Otero, L. J.; Restrepo, J. C.; Gonzalez, M.

2013-04-01

In this study, the tsunami hazard posed to 120 000 inhabitants of Tumaco (Colombia) is assessed, and an evaluation and analysis of regenerating the previous El Guano Island for tsunami protection is conducted. El Guano Island was a sandy barrier island in front of the city of Tumaco until its disappearance during the tsunami of 1979; the island is believed to have played a protective role, substantially reducing the scale of the disaster. The analysis is conducted by identifying seismotectonic parameters and focal mechanisms of tsunami generation in the area, determining seven potential generation sources, applying a numerical model for tsunami generation and propagation, and evaluating the effect of tsunamis on Tumaco. The results show that in the current situation, this area is vulnerable to impact and flooding by tsunamis originating nearby. El Guano Island was found to markedly reduce flood levels and the energy flux of tsunami waves in Tumaco during the 1979 tsunami. To reduce the risk of flooding due to tsunamis, the regeneration and morphological modification of El Guano Island would help to protect Tumaco.

Tsunamigenic potential of a newly discovered active fault zone in the outer Messina Strait, Southern Italy

NASA Astrophysics Data System (ADS)

Fu, Lili; Heidarzadeh, Mohammad; Cukur, Deniz; Chiocci, Francesco L.; Ridente, Domenico; Gross, Felix; Bialas, Jörg; Krastel, Sebastian

2017-03-01

The 1908 Messina tsunami was the most catastrophic tsunami hitting the coastline of Southern Italy in the younger past. The source of this tsunami, however, is still heavily debated, and both rupture along a fault and a slope failure have been postulated as potential origin of the tsunami. Here we report a newly discovered active Fiumefreddo-Melito di Porto Salvo Fault Zone (F-MPS_FZ), which is located in the outer Messina Strait in a proposed landslide source area of the 1908 Messina tsunami. Tsunami modeling showed that this fault zone would produce devastating tsunamis by assuming slip amounts of ≥5 m. An assumed slip of up to 17 m could even generate a tsunami comparable to the 1908 Messina tsunami, but we do not consider the F-MPS_FZ as a source for the 1908 Messina tsunami because its E-W strike contradicts seismological observations of the 1908 Messina earthquake. Future researches on the F-MPS_FZ, however, may contribute to the tsunami risk assessment in the Messina Strait.

Tsunami evacuation plans for future megathrust earthquakes in Padang, Indonesia, considering stochastic earthquake scenarios

NASA Astrophysics Data System (ADS)

Muhammad, Ario; Goda, Katsuichiro; Alexander, Nicholas A.; Kongko, Widjo; Muhari, Abdul

2017-12-01

This study develops tsunami evacuation plans in Padang, Indonesia, using a stochastic tsunami simulation method. The stochastic results are based on multiple earthquake scenarios for different magnitudes (Mw 8.5, 8.75, and 9.0) that reflect asperity characteristics of the 1797 historical event in the same region. The generation of the earthquake scenarios involves probabilistic models of earthquake source parameters and stochastic synthesis of earthquake slip distributions. In total, 300 source models are generated to produce comprehensive tsunami evacuation plans in Padang. The tsunami hazard assessment results show that Padang may face significant tsunamis causing the maximum tsunami inundation height and depth of 15 and 10 m, respectively. A comprehensive tsunami evacuation plan - including horizontal evacuation area maps, assessment of temporary shelters considering the impact due to ground shaking and tsunami, and integrated horizontal-vertical evacuation time maps - has been developed based on the stochastic tsunami simulation results. The developed evacuation plans highlight that comprehensive mitigation policies can be produced from the stochastic tsunami simulation for future tsunamigenic events.

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, G.; Lackner, M.; Haid, L.

2013-07-01

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation lengthmore » on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.« less

Implications of the 26 December 2004 Sumatra-Andaman earthquake on tsunami forecast and assessment models for great subduction-zone earthquakes

USGS Publications Warehouse

Geist, Eric L.; Titov, Vasily V.; Arcas, Diego; Pollitz, Fred F.; Bilek, Susan L.

2007-01-01

Results from different tsunami forecasting and hazard assessment models are compared with observed tsunami wave heights from the 26 December 2004 Indian Ocean tsunami. Forecast models are based on initial earthquake information and are used to estimate tsunami wave heights during propagation. An empirical forecast relationship based only on seismic moment provides a close estimate to the observed mean regional and maximum local tsunami runup heights for the 2004 Indian Ocean tsunami but underestimates mean regional tsunami heights at azimuths in line with the tsunami beaming pattern (e.g., Sri Lanka, Thailand). Standard forecast models developed from subfault discretization of earthquake rupture, in which deep- ocean sea level observations are used to constrain slip, are also tested. Forecast models of this type use tsunami time-series measurements at points in the deep ocean. As a proxy for the 2004 Indian Ocean tsunami, a transect of deep-ocean tsunami amplitudes recorded by satellite altimetry is used to constrain slip along four subfaults of the M >9 Sumatra–Andaman earthquake. This proxy model performs well in comparison to observed tsunami wave heights, travel times, and inundation patterns at Banda Aceh. Hypothetical tsunami hazard assessments models based on end- member estimates for average slip and rupture length (Mw 9.0–9.3) are compared with tsunami observations. Using average slip (low end member) and rupture length (high end member) (Mw 9.14) consistent with many seismic, geodetic, and tsunami inversions adequately estimates tsunami runup in most regions, except the extreme runup in the western Aceh province. The high slip that occurred in the southern part of the rupture zone linked to runup in this location is a larger fluctuation than expected from standard stochastic slip models. In addition, excess moment release (∼9%) deduced from geodetic studies in comparison to seismic moment estimates may generate additional tsunami energy, if the exponential time constant of slip is less than approximately 1 hr. Overall, there is significant variation in assessed runup heights caused by quantifiable uncertainty in both first-order source parameters (e.g., rupture length, slip-length scaling) and spatiotemporal complexity of earthquake rupture.

Field Survey of the 2015 Ilapel Tsunami in North Central Chile

NASA Astrophysics Data System (ADS)

Lagos, M.; Fritz, H. M.

2016-12-01

The magnitude Mw 8.3 earthquake in north-central Chile on September 16, 2015 generated a tsunami that rapidly flooded coastal areas. The tsunami impact was concentrated in Coquimbo region, while the regions of Valparaiso and Atacama were also affected. Fortunately, ancestral knowledge from the past tsunamis in the region, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. The event caused 11 fatalities: 8 were associated with the tsunami, while 3 were attributed to building collapses caused by the earthquake. The international scientist joined the local effort from September 20 to 26, 2015. The international tsunami survey team (ITST) interviewed numerous eyewitnesses and documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 500 km stretch of coastline from Caleta Chañaral de Aceituno (28.8° S) south of Huasco down to Llolleo near San Antonio (33.6° S). We surveyed more than 40 locations and recorded more than 100 tsunami and runup heights with differential GPS and integrated laser range finders. The tsunami impact peaked at Caleta Totoral near Punta Aldea with both tsunami and runup heights exceeding 10 m as surveyed on September 22. Runup exceeded 10 m at a second uninhabited location some 15 km south of Caleta Totoral. A significant variation in tsunami impact was observed along the coastlines of central Chile at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2015 Chile tsunami are compared with recent Chilean tsunamis. The tsunami was characterized by rapid arrival within minutes in the nearfield requiring spontaneous self-evacuation as warning messages did not reach some of the hardest hit fishing villages prior to tsunami arrival. The absence of a massive tsunami outside of the Coquimbo region may mislead evacuated residents in the adjacent Atacama and Valparaíso regions of Chile in potential future events. This event poses significant challenges to community-based education raising tsunami awareness.

The Tsunami Project: Integrating engineering, natural and social sciences into post-tsunami surveys

NASA Astrophysics Data System (ADS)

McAdoo, B. G.; Goff, J. R.; Fritz, H. M.; Cochard, R.; Kong, L. S.

2009-12-01

Complexities resulting from recent tsunamis in the Solomon Islands (2007), Java (2006) and Sumatra (2004, 2005) have demonstrated the need for an integrated, interdisciplinary team of engineers, natural and social scientists to better understand the nature of the disaster. Documenting the complex interactions in the coupled human-environment system necessitate a coordinated, interdisciplinary approach that combines the strengths of engineering, geoscience, ecology and social science. Engineers, modelers and geoscientists untangle the forces required to leave an imprint of a tsunami in the geologic record. These same forces affect ecosystems that provide services from buffers to food security; therefore coastal ecologists play a vital role. It is also crucial to understand the social structures that contribute to disasters, so local or regional policy experts, planners, economists, etc. should be included. When these experts arrive in a disaster area as part of an Interdisciplinary Tsunami Survey Team, the interactions between the systems can be discussed in the field, and site-specific data can be collected. A diverse team in the field following a tsunami shares critical resources and discoveries in real-time, making the survey more efficient. Following the 2006 Central Java earthquake and tsunami, civil engineers covered broad areas quickly, collecting ephemeral water level data and communicating areas of interest to the geologists, who would follow to do the slower sediment data collection. The 2007 Solomon Islands earthquake and tsunami caused extensive damage to the coral reef, which highlighting the need to have an ecologist on the team who was able to identify species and their energy tolerance. Rather than diluting the quality of post-tsunami data collection, this approach in fact strengthens it- engineers and geoscientists no longer have to indentify coral or mangrove species, nor do ecologists evaluate the velocity of a wave as it impacted a forested coastline. Interviews, a core element of post-tsunami surveys and which most US academic institutions require human-subject training to complete, can be undertaken by social scientists trained to ask pertinent questions to both the natural scientists and engineers, and those that will illuminate the underlying weaknesses of the social institutions that contributed to the magnitude of the disaster. Data collected by interdisciplinary teams provides baseline data that can set the redevelopment process off on the right track. Geoscientists constrain the location, frequency and magnitude of hazards, and how they affect the landscape. Ecologists document the interaction of hazards with ecosystems and evaluate their risk reduction role. Engineers and modelers constrain the effects of a hazard on the built environment. A coupled human-environment approach at the intersection of the physical, ecological and the built environments provides the right kind of data decision makers need to build back better in the most ecologically and economically sustainable manner.

Variety of Sedimentary Process and Distribution of Tsunami Deposits in Laboratory Experiments

NASA Astrophysics Data System (ADS)

Yamaguchi, N.; Sekiguchi, T.

2017-12-01

As an indicator of the history and magnitude of paleotsunami events, tsunami deposits have received considerable attention. To improve the identification and interpretation of paleotsunami deposits, an understanding of sedimentary process and distribution of tsunami deposits is crucial. Recent detailed surveys of onshore tsunami deposits including the 2004 Indian Ocean tsunami and the 2011 Tohoku-oki tsunami have revealed that terrestrial topography causes a variety of their features and distributions. Therefore, a better understanding of possible sedimentary process and distribution on such influential topographies is required. Flume experiments, in which sedimentary conditions can be easily controlled, can provide insights into the effects of terrestrial topography as well as tsunami magnitude on the feature of tsunami deposits. In this presentation, we report laboratory experiments that focused on terrestrial topography including a water body (e.g. coastal lake) on a coastal lowland and a cliff. In both cases, the results suggested relationship between the distribution of tsunami deposits and the hydraulic condition of the tsunami flow associated with the terrestrial topography. These experiments suggest that influential topography would enhance the variability in thickness of tsunami deposits, and thus, in reconstructions of paleotsunami events using sedimentary records, we should take into account such anomalous distribution of tsunami deposits. Further examination of the temporal sequence of sedimentary process in laboratory tsunamis may improve interpretation and estimation of paleotsunami events.

Open-Ocean and Coastal Properties of Recent Major Tsunamis

NASA Astrophysics Data System (ADS)

Rabinovich, A.; Thomson, R.; Zaytsev, O.

2017-12-01

The properties of six major tsunamis during the period 2009-2015 (2009 Samoa; 2010 Chile; 2011 Tohoku; 2012 Haida Gwaii; 2014 and 2015 Chile) were thoroughly examined using coastal data from British Columbia, the U.S. West Coast and Mexico, and offshore open-ocean DART and NEPTUNE stations. Based on joint spectral analyses of the tsunamis and background noise, we have developed a method to suppress the influence of local topography and to use coastal observations to determine the underlying spectra of tsunami waves in the deep ocean. The "reconstructed" open-ocean tsunami spectra were found to be in close agreement with the actual tsunami spectra evaluated from the analysis of directly measured open-ocean tsunami records. We have further used the spectral estimates to parameterize tsunamis based on their integral open-ocean spectral characteristics. Three key parameters are introduced to describe individual tsunami events: (1) Integral open-ocean energy; (2) Amplification factor (increase of the mean coastal tsunami variance relative to the open-ocean variance); and (3) Tsunami colour, the frequency composition of the open-ocean tsunami waves. In particular, we found that the strongest tsunamis, associated with large source areas (the 2010 Chile and 2011 Tohoku) are "reddish" (indicating the dominance of low-frequency motions), while small-source events (the 2009 Samoa and 2012 Haida Gwaii) are "bluish" (indicating strong prevalence of high-frequency motions).

What kind of disturbances did March 11, 2011 Tohoku Earthquake and Tsunamis leave continental margin ecosystems? : Lessons from five years monitoring research

NASA Astrophysics Data System (ADS)

Kitazato, Hiroshi; Kijima, Akihiro; Kogure, Kazuhiro; Hara, Motoyuki; Nagata, Toshi; Fujikura, Kasunori; Sonoda, Akira

2016-04-01

On March 11, 2011, huge earthquake with M9.0 took place at Japan Trench area off Northeast Japan. Vigorous disturbances of marine environments and ecosystems have taken place at coastal areas where huge tsunamis swept sediments and organisms away from the coastal areas to deeper oceans. Distributional pattern of sediments and organisms in coves and bays have strongly changed after tsunamis. Marine ecosystems at Northeast Japan have totally disturbed and damaged. Scientists from Tohoku University, the University of Tokyo and JAMSTEC have started to monitor how much marine ecosystem disturbed and how it may recover. A research team, named Tohoku Ecosystem-Associated Marine Sciences, continually makes research on marine ecosystems as ten years monitoring project funded by MEXT, Japan since 2011. On 2016, it takes five years from the Earthquake and Tsunami occurred. What happens marine ecosystems at Tohoku area during these years. Water column ecosystems are rather easy to recover from disturbances. Seaweed communities have strongly damaged, but, they gradually recover. Sediment communities have not recovered yet as sediment distribution is different from before earthquake and tsunamis. Most difficulties are scars in human minds. We, scientists, try to share scientific activities and results with local peoples including fishermen and local governments for better understanding of both oceanic conditions and fishery resources. Disaster risk reduction should accelerate with resilience of community structure. But, mental resilience is the most effective way to recover human activities at the damaged areas.

Sedimentological effects of tsunamis, with particular reference to impact-generated and volcanogenic waves

NASA Technical Reports Server (NTRS)

Bourgeois, Joanne; Wiberg, Patricia L.

1988-01-01

Impulse-generated waves (tsunamis) may be produced, at varying scales and global recurrence intervals (RI), by several processes. Meteorite-water impacts will produce tsunamis, and asteroid-scale impacts with associated mega-tsunamis may occur. A bolide-water impact would undoubtedly produce a major tsunami, whose sedimentological effects should be recognizable. Even a bolide-land impact might trigger major submarine landslides and thus tsunamis. In all posulated scenarios for the K/T boundary event, then, tsunamis are expected, and where to look for them must be determined, and how to distinguish deposits from different tsunamis. Also, because tsunamis decrease in height as they move away from their source, the proximal effects will differ by perhaps orders of magnitude from distal effects. Data on the characteristics of tsunamis at their origin are scarce. Some observations exist for tsunamis generated by thermonuclear explosions and for seismogenic tsunamis, and experimental work was conducted on impact-generated tsunamis. All tsunamis of interest have wave-lengths of 0(100) km and thus behave as shallow-water waves in all ocean depths. Typical wave periods are 0(10 to 100) minutes. The effect of these tsunamis can be estimated in the marine and coastal realm by calculating boundary shear stresses (expressed as U*, the shear velocity). An event layer at the K/T boundary in Texas occurs in mid-shelf muds. Only a large, long-period wave with a wave height of 0(50) m, is deemed sufficient to have produced this layer. Such wave heights imply a nearby volcanic explosion on the scale of Krakatau or larger, or a nearby submarine landslide also of great size, or a bolide-water impact in the ocean.

Modeling of influence from remote tsunami at the coast of Sakhalin and Kuriles islands.

NASA Astrophysics Data System (ADS)

Zaytsev, Andrey; Pelinovsky, Efim; Yalciner, Ahmet; Chernov, Anton; Kostenko, Irina

2010-05-01

The Far East coast of Russia (Kuriles islands, Sakhalin, Kamchatka) is the area where the dangerous natural phenomena as tsunami is located. A lot of works are established for decreasing of tsunami's influence. Tsunami mapping and mitigation strategy are given for some regions. The centers of Tsunami Warning System are opened, enough plenty of records of a tsunami are collected. The properties of local tsunami are studied well. At the same time, the catastrophic event of the Indonesian tsunami, which had happened in December, 2004, when the sufficient waves have reached the coasts of Africa and South America, it is necessary to note, that the coats, which was far from the epicenter of earthquakes can be effected by catastrophic influence. Moreover, it is practically unique case, when using Tsunami Warning System can reduce the number of human victims to zero. Development of the computer technologies, numerical methods for the solution of systems of the nonlinear differential equations makes computer modeling real and hypothetical tsunamis is the basic method of studying features of distribution of waves in water areas and their influence at coast. Numerical modeling of distribution of historical tsunami from the seismic sources in the Pacific Ocean was observed. The events with an epicenter, remote from Far East coast of Russia were considered. The estimation of the remote tsunami waves propagation was developed. Impact force of tsunamis was estimated. The features of passage of tsunami through Kuril Straits were considered. The spectral analysis of records in settlements of Sakhalin and Kuriles is lead. NAMI-DANCE program was used for tsunami propagation numerical modeling. It is used finite element numerical schemes for Shallow Water Equations and Nonlinear-Dispersive Equations, with use Nested Grid.

Development Of New Databases For Tsunami Hazard Analysis In California

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Barberopoulou, A.; Borrero, J. C.; Bryant, W. A.; Dengler, L. A.; Goltz, J. D.; Legg, M.; McGuire, T.; Miller, K. M.; Real, C. R.; Synolakis, C.; Uslu, B.

2009-12-01

The California Geological Survey (CGS) has partnered with other tsunami specialists to produce two statewide databases to facilitate the evaluation of tsunami hazard products for both emergency response and land-use planning and development. A robust, State-run tsunami deposit database is being developed that compliments and expands on existing databases from the National Geophysical Data Center (global) and the USGS (Cascadia). Whereas these existing databases focus on references or individual tsunami layers, the new State-maintained database concentrates on the location and contents of individual borings/trenches that sample tsunami deposits. These data provide an important observational benchmark for evaluating the results of tsunami inundation modeling. CGS is collaborating with and sharing the database entry form with other states to encourage its continued development beyond California’s coastline so that historic tsunami deposits can be evaluated on a regional basis. CGS is also developing an internet-based, tsunami source scenario database and forum where tsunami source experts and hydrodynamic modelers can discuss the validity of tsunami sources and their contribution to hazard assessments for California and other coastal areas bordering the Pacific Ocean. The database includes all distant and local tsunami sources relevant to California starting with the forty scenarios evaluated during the creation of the recently completed statewide series of tsunami inundation maps for emergency response planning. Factors germane to probabilistic tsunami hazard analyses (PTHA), such as event histories and recurrence intervals, are also addressed in the database and discussed in the forum. Discussions with other tsunami source experts will help CGS determine what additional scenarios should be considered in PTHA for assessing the feasibility of generating products of value to local land-use planning and development.

Fluid-structure interaction simulation of floating structures interacting with complex, large-scale ocean waves and atmospheric turbulence with application to floating offshore wind turbines

NASA Astrophysics Data System (ADS)

Calderer, Antoni; Guo, Xin; Shen, Lian; Sotiropoulos, Fotis

2018-02-01

We develop a numerical method for simulating coupled interactions of complex floating structures with large-scale ocean waves and atmospheric turbulence. We employ an efficient large-scale model to develop offshore wind and wave environmental conditions, which are then incorporated into a high resolution two-phase flow solver with fluid-structure interaction (FSI). The large-scale wind-wave interaction model is based on a two-fluid dynamically-coupled approach that employs a high-order spectral method for simulating the water motion and a viscous solver with undulatory boundaries for the air motion. The two-phase flow FSI solver is based on the level set method and is capable of simulating the coupled dynamic interaction of arbitrarily complex bodies with airflow and waves. The large-scale wave field solver is coupled with the near-field FSI solver with a one-way coupling approach by feeding into the latter waves via a pressure-forcing method combined with the level set method. We validate the model for both simple wave trains and three-dimensional directional waves and compare the results with experimental and theoretical solutions. Finally, we demonstrate the capabilities of the new computational framework by carrying out large-eddy simulation of a floating offshore wind turbine interacting with realistic ocean wind and waves.

Introduction to “Global tsunami science: Past and future, Volume I”

USGS Publications Warehouse

Geist, Eric L.; Fritz, Hermann; Rabinovich, Alexander B.; Tanioka, Yuichiro

2016-01-01

Twenty-five papers on the study of tsunamis are included in Volume I of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Six papers examine various aspects of tsunami probability and uncertainty analysis related to hazard assessment. Three papers relate to deterministic hazard and risk assessment. Five more papers present new methods for tsunami warning and detection. Six papers describe new methods for modeling tsunami hydrodynamics. Two papers investigate tsunamis generated by non-seismic sources: landslides and meteorological disturbances. The final three papers describe important case studies of recent and historical events. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Introduction to "Global Tsunami Science: Past and Future, Volume I"

NASA Astrophysics Data System (ADS)

Geist, Eric L.; Fritz, Hermann M.; Rabinovich, Alexander B.; Tanioka, Yuichiro

2016-12-01

Twenty-five papers on the study of tsunamis are included in Volume I of the PAGEOPH topical issue "Global Tsunami Science: Past and Future". Six papers examine various aspects of tsunami probability and uncertainty analysis related to hazard assessment. Three papers relate to deterministic hazard and risk assessment. Five more papers present new methods for tsunami warning and detection. Six papers describe new methods for modeling tsunami hydrodynamics. Two papers investigate tsunamis generated by non-seismic sources: landslides and meteorological disturbances. The final three papers describe important case studies of recent and historical events. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

An unified numerical simulation of seismic ground motion, ocean acoustics, coseismic deformations and tsunamis of 2011 Tohoku earthquake

NASA Astrophysics Data System (ADS)

Maeda, T.; Furumura, T.; Noguchi, S.; Takemura, S.; Iwai, K.; Lee, S.; Sakai, S.; Shinohara, M.

2011-12-01

The fault rupture of the 2011 Tohoku (Mw9.0) earthquake spread approximately 550 km by 260 km with a long source rupture duration of ~200 s. For such large earthquake with a complicated source rupture process the radiation of seismic wave from the source rupture and initiation of tsunami due to the coseismic deformation is considered to be very complicated. In order to understand such a complicated process of seismic wave, coseismic deformation and tsunami, we proposed a unified approach for total modeling of earthquake induced phenomena in a single numerical scheme based on a finite-difference method simulation (Maeda and Furumura, 2011). This simulation model solves the equation of motion of based on the linear elastic theory with equilibrium between quasi-static pressure and gravity in the water column. The height of tsunami is obtained from this simulation as a vertical displacement of ocean surface. In order to simulate seismic waves, ocean acoustics, coseismic deformations, and tsunami from the 2011 Tohoku earthquake, we assembled a high-resolution 3D heterogeneous subsurface structural model of northern Japan. The area of simulation is 1200 km x 800 km and 120 km in depth, which have been discretized with grid interval of 1 km in horizontal directions and 0.25 km in vertical direction, respectively. We adopt a source-rupture model proposed by Lee et al. (2011) which is obtained by the joint inversion of teleseismic, near-field strong motion, and coseismic deformation. For conducting such a large-scale simulation, we fully parallelized our simulation code based on a domain-partitioning procedure which achieved a good speed-up by parallel computing up to 8192 core processors with parallel efficiency of 99.839%. The simulation result demonstrates clearly the process in which the seismic wave radiates from the complicated source rupture over the fault plane and propagating in heterogeneous structure of northern Japan. Then, generation of tsunami from coseismic ground deformation at sea floor due to the earthquake and propagation is also well demonstrated . The simulation also demonstrates that a very large slip up to 40 m at shallow plate boundary near the trench pushes up sea floor with source rupture propagation, and the highly elevated sea surface gradually start propagation as tsunamis due to the gravity. The result of simulation of vertical-component displacement waveform matches the ocean-bottom pressure gauge record which is installed just above the source fault area (Maeda et al., 2011) very consistently. Strong reverberation of the ocean-acoustic waves between sea surface and sea bottom particularly near the Japan Trench for long time after the source rupture ends is confirmed in the present simulation. Accordingly, long wavetrains of high-frequency ocean acoustic waves is developed and overlap to later tsunami waveforms as we found in the observations.

Anatomy of Historical Tsunamis: Lessons Learned for Tsunami Warning

NASA Astrophysics Data System (ADS)

Igarashi, Y.; Kong, L.; Yamamoto, M.; McCreery, C. S.

2011-11-01

Tsunamis are high-impact disasters that can cause death and destruction locally within a few minutes of their occurrence and across oceans hours, even up to a day, afterward. Efforts to establish tsunami warning systems to protect life and property began in the Pacific after the 1946 Aleutian Islands tsunami caused casualties in Hawaii. Seismic and sea level data were used by a central control center to evaluate tsunamigenic potential and then issue alerts and warnings. The ensuing events of 1952, 1957, and 1960 tested the new system, which continued to expand and evolve from a United States system to an international system in 1965. The Tsunami Warning System in the Pacific (ITSU) steadily improved through the decades as more stations became available in real and near-real time through better communications technology and greater bandwidth. New analysis techniques, coupled with more data of higher quality, resulted in better detection, greater solution accuracy, and more reliable warnings, but limitations still exist in constraining the source and in accurately predicting propagation of the wave from source to shore. Tsunami event data collected over the last two decades through international tsunami science surveys have led to more realistic models for source generation and inundation, and within the warning centers, real-time tsunami wave forecasting will become a reality in the near future. The tsunami warning system is an international cooperative effort amongst countries supported by global and national monitoring networks and dedicated tsunami warning centers; the research community has contributed to the system by advancing and improving its analysis tools. Lessons learned from the earliest tsunamis provided the backbone for the present system, but despite 45 years of experience, the 2004 Indian Ocean tsunami reminded us that tsunamis strike and kill everywhere, not just in the Pacific. Today, a global intergovernmental tsunami warning system is coordinated under the United Nations. This paper reviews historical tsunamis, their warning activities, and their sea level records to highlight lessons learned with the focus on how these insights have helped to drive further development of tsunami warning systems and their tsunami warning centers. While the international systems do well for teletsunamis, faster detection, more accurate evaluations, and widespread timely alerts are still the goals, and challenges still remain to achieving early warning against the more frequent and destructive local tsunamis.

Hydraulic experimental investigation on spatial distribution and formation process of tsunami deposit on a slope

NASA Astrophysics Data System (ADS)

Harada, K.; Takahashi, T.; Yamamoto, A.; Sakuraba, M.; Nojima, K.

2017-12-01

An important aim of the study of tsunami deposits is to estimate the characteristics of past tsunamis from the tsunami deposits found locally. Based on the tsunami characteristics estimated from tsunami deposit, it is possible to examine tsunami risk assessment in coastal areas. It is considered that tsunami deposits are formed based on the dynamic correlation between tsunami's hydraulic values, sediment particle size, topography, etc. However, it is currently not enough to evaluate the characteristics of tsunamis from tsunami deposits. This is considered to be one of the reasons that the understanding of the formation process of tsunami deposits is not sufficiently understood. In this study, we analyze the measurement results of hydraulic experiment (Yamamoto et al., 2016) and focus on the formation process and distribution of tsunami deposits. Hydraulic experiment was conducted with two-dimensional water channel with a slope. Tsunami was inputted as a bore wave flow. The moving floor section was installed as a seabed slope connecting to shoreline and grain size distribution was set some cases. The water level was measured using ultrasonic displacement gauges, and the flow velocity was measured using propeller current meters and an electromagnetic current meter. The water level and flow velocity was measured at some points. The distribution of tsunami deposit was measured from shoreline to run-up limit on the slope. Yamamoto et al. (2016) reported the measurement results on the distribution of tsunami deposit with wave height and sand grain size. Therefore, in this study, hydraulic analysis of tsunami sediment formation process was examined based on the measurement data. Time series fluctuation of hydraulic parameters such as Froude number, Shields number, Rouse number etc. was calculated to understand on the formation process of tsunami deposit. In the front part of the tsunami, the flow velocity take strong flow from shoreline to around the middle of slope. From the measurement result in this time, it is considered that the dominant process of deposit formation is suspended state. At the run-up limit where the flow velocity decreases, the sediment moves in bedload state. As a result, the amount of sediment transport near the run-up limit changes under the influence of particle size.

Peru 2007 tsunami runup observations and modeling

NASA Astrophysics Data System (ADS)

Fritz, H. M.; Kalligeris, N.; Borrero, J. C.

2008-05-01

On 15 August 2007 an earthquake with moment magnitude (Mw) of 8.0 centered off the coast of central Peru, generated a tsunami with locally focused runup heights of up to 10 m. A reconnaissance team was deployed in the immediate aftermath and investigated the tsunami effects at 51 sites. The largest runup heights were measured in a sparsely populated desert area south of the Paracas Peninsula resulting in only 3 tsunami fatalities. Numerical modeling of the earthquake source and tsunami suggest that a region of high slip near the coastline was primarily responsible for the extreme runup heights. The town of Pisco was spared by the presence of the Paracas Peninsula, which blocked tsunami waves from propagating northward from the high slip region. The coast of Peru has experienced numerous deadly and destructive tsunamis throughout history, which highlights the importance of ongoing tsunami awareness and education efforts in the region. The Peru tsunami is compared against recent mega-disasters such as the 2004 Indian Ocean tsunami and Hurricane Katrina.

The Impacts Of The Indian Ocean Tsunami On Coastal Ecosystems And Resultant Effects On The Human Communities Of Sri Lanka

NASA Astrophysics Data System (ADS)

Ingram, J.; Rumbaitis-del Rio, C.; Franco, G.; Khazai, B.

2005-12-01

The devastating tsunami that hit Sri Lanka on December 26, 2004 has demonstrated vividly the inter-connections between social and ecological resilience. Before the tsunami, the coastal zone of Sri Lanka was inhabited by predominantly poor populations, most of whom were directly dependent upon coastal natural resources, such as fisheries and coconut trees, for supporting their livelihoods. Many of these people have now lost their livelihoods through the destruction of their boats and nets for fishing, the contamination of drinking sources, homes, family members and assets. This presentation focuses on observations of the tsunami impacts on both social and ecological communities made along the affected coastline of Sri Lanka in April-May 2005. This assessment recorded patterns of ecological resistance and damage resulting from the tsunami in relation to damage on the human environment, with an exploration of the physical factors that may have contributed to vulnerability or resistance. This work also involved a preliminary assessment of the resilience and recovery of different natural resource based livelihood strategies following the disaster and an exploration of livelihood possibilities in proposed resettlement sites. From observations made in this and other recent studies, it is apparent that intact ecosystems played a vital role in protection from the impact of the tsunami and are vital for supporting people as they seek to rebuild their livelihoods. However, certain structural and biological characteristics appear to offer certain tree species, such as coconut (Cocos nucifera), an advantage in surviving such events and have been important for providing food and drink to people in the days after the tsunami. Areas where significant environmental damage had occurred prior to the tsunami or where there were few natural defenses present to protect human communities, devastation of homes and lives was extremely high. Although, there is evidence that many previously intact ecological systems were little affected or will recover from this large disturbance, major impacts on the natural environment may come in the aftermath of the tsunami during the rebuilding and reconstruction phase. The ability of communities to recover from disasters and to rebuild their lives is dependent on both an intact natural resource base and the maintenance of social networks for learning, adapting and managing resources. The potential impacts of rebuilding on the natural environment combined with policies on resettlement may influence the ability to learn, cope and manage such events and resources in the future.

Sedimentary deposits of the 26 December 2004 tsunami on the northwest coast of Aceh, Indonesia

USGS Publications Warehouse

Moore, A.; Nishimura, Y.; Gelfenbaum, G.; Kamataki, T.; Triyono, R.

2006-01-01

The 2004 Sumatra-Andaman tsunami flooded coastal northern Sumatra to a depth of over 20 m, deposited a discontinuous sheet of sand up to 80 cm thick, and left mud up to 5 km inland. In most places the sand sheet is normally graded, and in some it contains complex internal stratigraphy. Structures within the sand sheet may record the passage of up to 3 individual waves. We studied the 2004 tsunami deposits in detail along a flow-parallel transect about 400 m long, 16 km southwest of Banda Aceh. Near the shore along this transect, the deposit is thin or absent. Between 50 and 400 m inland it ranges in thickness from 5 to 20 cm. The main trend in thickness is a tendency to thicken by filling low spots, most dramatically at pre-existing stream channels. Deposition generally attended inundation - along the transect, the tsunami deposited sand to within about 40 m of the inundation limit. Although the tsunami deposit contains primarily material indistinguishable from material found on the beach one month after the event, it also contains grain sizes and compositions unavailable on the current beach. Along the transect we studied, these grains become increasingly dominant both landward and upward in the deposit; possibly some landward source of sediment was exposed and exploited by the passage of the waves. The deposit also contains the unabraded shells of subtidal marine organisms, suggesting that at least part of the deposit came from offshore. Grain sizes within the deposit tend to fine upward and landward, although individual units within the deposit appear massive, or show reverse grading. Sorting becomes better landward, although the most landward sites generally become poorly sorted from the inclusion of soil clasts. These sites commonly show interlayering of sandy units and soil clast units. Deposits from the 2004 tsunami in Sumatra demonstrate the complex nature of the deposits of large tsunamis. Unlike the deposits of smaller tsunamis, internal stratigraphy is complex, and will require some effort to understand. The Sumatra deposits also show the contribution of multiple sediment sources, each of which has its own composition and grain size. Such complexity may allow more accurate modeling of flow depth and flow velocity for paleotsunamis, if an understanding of how tsunami hydraulics affect sedimentation can be established. Copyright ?? The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

Tsunami Hockey

NASA Astrophysics Data System (ADS)

Weinstein, S.; Becker, N. C.; Wang, D.; Fryer, G. J.

2013-12-01

An important issue that vexes tsunami warning centers (TWCs) is when to cancel a tsunami warning once it is in effect. Emergency managers often face a variety of pressures to allow the public to resume their normal activities, but allowing coastal populations to return too quickly can put them at risk. A TWC must, therefore, exercise caution when cancelling a warning. Kim and Whitmore (2013) show that in many cases a TWC can use the decay of tsunami oscillations in a harbor to forecast when its amplitudes will fall to safe levels. This technique should prove reasonably robust for local tsunamis (those that are potentially dangerous within only 100 km of their source region) and for regional tsunamis (whose danger is limited to within 1000km of the source region) as well. For ocean-crossing destructive tsunamis such as the 11 March 2011 Tohoku tsunami, however, this technique may be inadequate. When a tsunami propagates across the ocean basin, it will encounter topographic obstacles such as seamount chains or coastlines, resulting in coherent reflections that can propagate great distances. When these reflections reach previously-impacted coastlines, they can recharge decaying tsunami oscillations and make them hazardous again. Warning center scientists should forecast sea-level records for 24 hours beyond the initial tsunami arrival in order to observe any potential reflections that may pose a hazard. Animations are a convenient way to visualize reflections and gain a broad geographic overview of their impacts. The Pacific Tsunami Warning Center has developed tools based on tsunami simulations using the RIFT tsunami forecast model. RIFT is a linear, parallelized numerical tsunami propagation model that runs very efficiently on a multi-CPU system (Wang et al, 2012). It can simulate 30-hours of tsunami wave propagation in the Pacific Ocean at 4 arc minute resolution in approximately 6 minutes of real time on a 12-CPU system. Constructing a 30-hour animation using 1 minute simulated time steps takes approximately 50 minutes on the same system. These animations are generated quickly enough to provide decision support for emergency managers whose coastlines may be impacted by the tsunami several hours later. Tsunami reflections can also aid in determining the source region for those tsunamis generated by non-seismic mechanisms without a clear source such as meteotsunamis, tsunamis generated by meteorological phenomena. A derecho that crossed the New Jersey coast and entered the Atlantic Ocean at approximately 1500 UTC June 13, 2013 generated a meteotsunami that struck the northeast coast of the US causing several injuries. A DART sensor off Montauk, NY, recorded tsunami waves approximately 200 minutes apart. We show how the arrival times of the tsunamis recorded by this DART can help to constrain the source region of the meteotsunami. We also examine other reflections produced by the Haida Gwaii 2012, Tohoku 2011, and other tsunamis.

A culture of tsunami preparedness and applying knowledge from recent tsunamis affecting California

NASA Astrophysics Data System (ADS)

Miller, K. M.; Wilson, R. I.

2012-12-01

It is the mission of the California Tsunami Program to ensure public safety by protecting lives and property before, during, and after a potentially destructive or damaging tsunami. In order to achieve this goal, the state has sought first to use finite funding resources to identify and quantify the tsunami hazard using the best available scientific expertise, modeling, data, mapping, and methods at its disposal. Secondly, it has been vital to accurately inform the emergency response community of the nature of the threat by defining inundation zones prior to a tsunami event and leveraging technical expertise during ongoing tsunami alert notifications (specifically incoming wave heights, arrival times, and the dangers of strong currents). State scientists and emergency managers have been able to learn and apply both scientific and emergency response lessons from recent, distant-source tsunamis affecting coastal California (from Samoa in 2009, Chile in 2010, and Japan in 2011). Emergency managers must understand and plan in advance for specific actions and protocols for each alert notification level provided by the NOAA/NWS West Coast/Alaska Tsunami Warning Center. Finally the state program has provided education and outreach information via a multitude of delivery methods, activities, and end products while keeping the message simple, consistent, and focused. The goal is a culture of preparedness and understanding of what to do in the face of a tsunami by residents, visitors, and responsible government officials. We provide an update of results and findings made by the state program with support of the National Tsunami Hazard Mitigation Program through important collaboration with other U.S. States, Territories and agencies. In 2009 the California Emergency Management Agency (CalEMA) and the California Geological Survey (CGS) completed tsunami inundation modeling and mapping for all low-lying, populated coastal areas of California to assist local jurisdictions on the coast in the identification of areas possible to be inundated in a tsunami. "Tsunami Inundation Maps for Emergency Planning" have provided the basis for some of the following preparedness, planning, and education activities in California: Improved evacuation and emergency response plans; Production of multi-language brochures: statewide, community, and boating; Development and support of tsunami scenario-driven exercises and drills; Development of workshops to educate both emergency managers and public; and Establishment of a comprehensive information website www.tsunami.ca.gov; and a preparedness website myhazards.calema.ca.gov. In addition, the California Tsunami Program has a number of initiatives underway through existing work plans to continue to apply scientifically vetted information toward comprehensive public understanding of the threat from future tsunamis to constituents on the coast. These include projects to: Complete tsunami land-use planning maps for California communities, Develop in-harbor tsunami hazard maps statewide, Complete modeling of offshore safety zones for the maritime community, Complete preliminary tsunami risk analysis for state utilizing new HAZUS tsunami module and probabilistic analysis results, and Develop a post-tsunami recovery and resiliency plan for the state.

Elders recall an earlier tsunami on Indian Ocean shores

USGS Publications Warehouse

Kakar, Din Mohammad; Naeem, Ghazala; Usman, Abdullah; Hasan, Haider; Lohdi, Hira; Srinivasalu, Seshachalam; Andrade, Vanessa; Rajendran, C.P.; Naderi Beni, Abdolmajid; Hamzeh, Mohammad Ali; Hoffmann, Goesta; Al Balushi, Noora; Gale, Nora; Kodijat, Ardito; Fritz, Hermann M.; Atwater, Brian F.

2014-01-01

Ten years on, the Indian Ocean tsunami of 26 December 2004 still looms large in efforts to reduce coastal risk. The disaster has spurred worldwide advances in tsunami detection and warning, tsunami-risk assessment, and tsunami awareness [Satake, 2014]. Nearly a lifetime has passed since the northwestern Indian Ocean last produced a devastating tsunami. Documentation of this tsunami, in November 1945, was hindered by international instability in the wake of the Second World War and, in British India, by the approach of independence and partition. The parent earthquake, of magnitude 8.1, was widely recorded, and the tsunami registered on tide gauges, but intelligence reports and newspaper articles say little about inundation limits while permitting a broad range of catalogued death tolls. What has been established about the 1945 tsunami falls short of what's needed today for ground-truthing inundation models, estimating risk to enlarged populations, and anchoring awareness campaigns in local facts. Recent efforts to reduce coastal risk around the Arabian Sea include a project in which eyewitnesses to the 1945 tsunami were found and interviewed (Fig. 1), and related archives were gathered. Results are being made available through UNESCO's Indian Ocean Tsunami Information Center in hopes of increasing scientific understanding and public awareness of the region's tsunami hazards.

The 2004 Sumatra tsunami in the southeastern Pacific: Coastal and offshore measurements and numerical modeling

NASA Astrophysics Data System (ADS)

Moore, C. W.; Eble, M. C.; Rabinovich, A.; Titov, V. V.

2016-12-01

The Mw = 9.3 megathrust earthquake of December 26, 2004 off the coast of Sumatra generated a catastrophic tsunami that crossed the Indian Ocean and was widespread in the Pacific and Atlantic oceans being recorded by a great number of coastal tide gauges located in 15-25 thousand kilometers from the source area. The data from these instruments throughout the world oceans enabled estimates of various statistical parameters and energy decay of this event. However, only very few open-ocean records of this tsunami had been obtained. A unique high-resolution record of this tsunami from DART 32401 located offshore of northern Chile, combined with the South American mainland tide gauge measurements and the data from three island stations (San Felix, Juan Fernandez and Easter) enabled us to examine far-field characteristics of the event in the southeastern Pacific and to compare the results of global numerical simulations with observations. The maximum wave height measured at DART 32401 was only 1.8 cm but the signal was very clear and reliable. Despite their small heights, the waves demonstrated consistent spatial and temporal structure and good agreement with DART 46405/NeMO records in the NE Pacific. The travel time from the source area to DART 32401 was 25h 55min in good agreement with the computed travel time (25h 45min) and consistent with the times obtained from the nearby coastal tide gauges. This agreement was much better than it followed from the direct travel time estimation based classical kinematic theory that gave the travel time approximately 1.5 hrs shorter than observed. The later actual arrival of the 2004 tsunami waves corresponds to the most energetically economic path along the mid-ocean ridge wave-guides, which is distinctly reproduced by the numerical model. Also, the numerical model described well the frequency content, amplitudes and general structure of the observed waves at this DART and the three island stations. Maximum wave heights in this region were identified at Arica (72 cm) and Callao (65 cm). The open-ocean and coastal records indicate that the 2004 tsunami wave energy occupied the period band of 6 min to 3.7 hrs with the main energy concentrated at periods of 30 to 70 min and peak values at 40 min.

Using Point Clouds Generated from Unmanned Aerial Vehicles Imagery Processed with Structure from Motion to Address Tsunami vs Storm Wave Boulder Deposition in Watu Karung, Indonesia

NASA Astrophysics Data System (ADS)

Uribe, A. T.; Bunds, M. P.; Andreini, J.; Horns, D. M.; Harris, R. A.; Prasetyadi, C.; Yulianto, E.; Putra, P. S.

2017-12-01

Tsunamis pose a major hazard to coastal communities along the south coast of much of Indonesia due its location on the Australian-Sunda arc. Furthermore, tsunamis and high-energy wave events are the principal drivers of geomorphic change in the area and it is difficult to distinguish the effects of each. A potentially useful indicator of past tsunami activity is coastal imbricated boulder deposits. To address whether an imbricated boulder deposit located on a beach in Watu Karung (Java, Indonesia) could have been formed by non-tsunami wave activity and to investigate coastal geomorphic change, we generated three pairs of digital surface models (DSMs) over an approximately one year period using photographs taken from a small unmanned aerial vehicle and structure-from-motion photogrammetry. The first two DSMs were made from photographs taken on 7/30-31/2016 and 8/2/2016, immediately before and after a significant 4.2 m swell struck the beach during a +2.5 m spring high tide. The third DSM pair was made from imagery collected 7/12/2017. Each pair of DSMs consists of a 1 cm pixel DSM of the boulder deposit and a 4 cm DSM of the larger beach area that surrounds the boulders. In addition, prior to the 2016 wave event 21 boulders up to 75 kg were marked and hand-placed shoreward of the boulder deposit; their movement was tracked with RTK GPS measurements. In the 2016 wave event, every hand-placed boulder moved, with an average displacement of 27.6 m. At the same time, approximately 20 of 650 naturally - occurring boulders, up to 2 m in length, moved more than 10 cm and up to 5.6 m. Between 2016 and 2017, approximately 300 of 650 naturally - occurring boulders with an average length of 1.6 m moved varying distances of at least 10 cm and up to 30 m. In addition, changes in beach sand volume occurred in ten 25 m2 localized zones on the beach with an average volume change of approximately 65 m2. Changes in both boulder position and sand volume occurred during the 2016 to 2017 time period when no tsunamis affected Watu Karung—thus indicating that all changes were the result of storm wave events.

Towards an Earthquake and Tsunami Early Warning in the Caribbean

NASA Astrophysics Data System (ADS)

Huerfano Moreno, V. A.; Vanacore, E. A.

2017-12-01

The Caribbean region (CR) has a documented history of large damaging earthquakes and tsunamis that have affected coastal areas, including the events of Jamaica in 1692, Virgin Islands in 1867, Puerto Rico in 1918, the Dominican Republic in 1946 and Haiti in 2010. There is clear evidence that tsunamis have been triggered by large earthquakes that deformed the ocean floor around the Caribbean Plate boundary. The CR is monitored jointly by national/regional/local seismic, geodetic and sea level networks. All monitoring institutions are participating in the UNESCO ICG/Caribe EWS, the purpose of this initiative is to minimize loss of life and destruction of property, and to mitigate against catastrophic economic impacts via promoting local research, real time (RT) earthquake, geodetic and sea level data sharing and improving warning capabilities and enhancing education and outreach strategies. Currently more than, 100 broad-band seismic, 65 sea levels and 50 GPS high rate stations are available in real or near real-time. These real-time streams are used by Local/Regional or Worldwide detection and warning institutions to provide earthquake source parameters in a timely manner. Currently, any Caribbean event detected to have a magnitude greater than 4.5 is evaluated, and sea level is measured, by the TWC for tsumanigenic potential. The regional cooperation is motivated both by research interests as well as geodetic, seismic and tsunami hazard monitoring and warning. It will allow the imaging of the tectonic structure of the Caribbean region to a high resolution which will consequently permit further understanding of the seismic source properties for moderate and large events and the application of this knowledge to procedures of civil protection. To reach its goals, the virtual network has been designed following the highest technical standards: BB sensors, 24 bits A/D converters with 140 dB dynamic range, real-time telemetry. Here we will discuss the state of the PR component of this virtual network as well as current advances in the imaging of the PR tectonic structure. The goal of this presentation is to describe the Puerto Rico Seismic Network (PRSN) system, including the real time earthquake and tsunami monitoring as well as the specific protocols used to broadcast earthquake/tsunami messages locally.

Heavy minerals in the 2011 Tohoku-oki tsunami deposits—insights into sediment sources and hydrodynamics

NASA Astrophysics Data System (ADS)

Jagodziński, Robert; Sternal, Beata; Szczuciński, Witold; Chagué-Goff, Catherine; Sugawara, Daisuke

2012-12-01

The 2011 Tohoku-oki tsunami left sand and mud deposits more than 4 km inland on the coastal plain of Sendai, Japan. The tsunami deposits, pre-tsunami soils and beach sediments were analysed for grain size, and heavy mineral content and assemblages to test the applicability of heavy mineral analyses in the identification of tsunami deposits and interpretation of associated sedimentation processes. Heavy minerals comprised on average 35% of the tsunami deposit in the 0.125-0.25 mm grain size fraction. The most common were orthopyroxenes, clinopyroxenes, amphiboles, limonites and opaque minerals. Heavy mineral concentrations and assemblages were similar in the tsunami deposits, beach and pre-tsunami soils and sediments and thus tsunami deposits could not simply be identified based on their heavy minerals. Sediment provenance analysis revealed that tsunami deposits left within 1.5 km of the shoreline were mostly eroded from the beach, dune and local soils, while deposits farther inland (> 1.5 km) were mostly derived from local soil erosion. No evidence was found for a significant contribution of offshore sediments. Detailed analyses revealed that the lowermost portion of tsunami deposits was mostly of local origin, while the sediment source of the upper portion was variable. A comparison with a previous study of heavy minerals in 2004 IOT deposits confirms that heavy minerals in tsunami deposits are mostly source-dependent and may represent a useful supplementary tool in studies of tsunami deposits. However, the interpretation must always be placed in the local geological context and corroborated with other "tsunami proxies".

Solomon Islands 2007 Tsunami Near-Field Modeling and Source Earthquake Deformation

NASA Astrophysics Data System (ADS)

Uslu, B.; Wei, Y.; Fritz, H.; Titov, V.; Chamberlin, C.

2008-12-01

The earthquake of 1 April 2007 left behind momentous footages of crust rupture and tsunami impact along the coastline of Solomon Islands (Fritz and Kalligeris, 2008; Taylor et al., 2008; McAdoo et al., 2008; PARI, 2008), while the undisturbed tsunami signals were also recorded at nearby deep-ocean tsunameters and coastal tide stations. These multi-dimensional measurements provide valuable datasets to tackle the challenging aspects at the tsunami source directly by inversion from tsunameter records in real time (available in a time frame of minutes), and its relationship with the seismic source derived either from the seismometer records (available in a time frame of hours or days) or from the crust rupture measurements (available in a time frame of months or years). The tsunami measurements in the near field, including the complex vertical crust motion and tsunami runup, are particularly critical to help interpreting the tsunami source. This study develops high-resolution inundation models for the Solomon Islands to compute the near-field tsunami impact. Using these models, this research compares the tsunameter-derived tsunami source with the seismic-derived earthquake sources from comprehensive perceptions, including vertical uplift and subsidence, tsunami runup heights and their distributional pattern among the islands, deep-ocean tsunameter measurements, and near- and far-field tide gauge records. The present study stresses the significance of the tsunami magnitude, source location, bathymetry and topography in accurately modeling the generation, propagation and inundation of the tsunami waves. This study highlights the accuracy and efficiency of the tsunameter-derived tsunami source in modeling the near-field tsunami impact. As the high- resolution models developed in this study will become part of NOAA's tsunami forecast system, these results also suggest expanding the system for potential applications in tsunami hazard assessment, search and rescue operations, as well as event and post-event planning in the Solomon Islands.

Development, testing, and applications of site-specific tsunami inundation models for real-time forecasting

NASA Astrophysics Data System (ADS)

Tang, L.; Titov, V. V.; Chamberlin, C. D.

2009-12-01

The study describes the development, testing and applications of site-specific tsunami inundation models (forecast models) for use in NOAA's tsunami forecast and warning system. The model development process includes sensitivity studies of tsunami wave characteristics in the nearshore and inundation, for a range of model grid setups, resolutions and parameters. To demonstrate the process, four forecast models in Hawaii, at Hilo, Kahului, Honolulu, and Nawiliwili are described. The models were validated with fourteen historical tsunamis and compared with numerical results from reference inundation models of higher resolution. The accuracy of the modeled maximum wave height is greater than 80% when the observation is greater than 0.5 m; when the observation is below 0.5 m the error is less than 0.3 m. The error of the modeled arrival time of the first peak is within 3% of the travel time. The developed forecast models were further applied to hazard assessment from simulated magnitude 7.5, 8.2, 8.7 and 9.3 tsunamis based on subduction zone earthquakes in the Pacific. The tsunami hazard assessment study indicates that use of a seismic magnitude alone for a tsunami source assessment is inadequate to achieve such accuracy for tsunami amplitude forecasts. The forecast models apply local bathymetric and topographic information, and utilize dynamic boundary conditions from the tsunami source function database, to provide site- and event-specific coastal predictions. Only by combining a Deep-ocean Assessment and Reporting of Tsunami-constrained tsunami magnitude with site-specific high-resolution models can the forecasts completely cover the evolution of earthquake-generated tsunami waves: generation, deep ocean propagation, and coastal inundation. Wavelet analysis of the tsunami waves suggests the coastal tsunami frequency responses at different sites are dominated by the local bathymetry, yet they can be partially related to the locations of the tsunami sources. The study also demonstrates the nonlinearity between offshore and nearshore maximum wave amplitudes.

Global Tsunami Database: Adding Geologic Deposits, Proxies, and Tools

NASA Astrophysics Data System (ADS)

Brocko, V. R.; Varner, J.

2007-12-01

A result of collaboration between NOAA's National Geophysical Data Center (NGDC) and the Cooperative Institute for Research in the Environmental Sciences (CIRES), the Global Tsunami Database includes instrumental records, human observations, and now, information inferred from the geologic record. Deep Ocean Assessment and Reporting of Tsunamis (DART) data, historical reports, and information gleaned from published tsunami deposit research build a multi-faceted view of tsunami hazards and their history around the world. Tsunami history provides clues to what might happen in the future, including frequency of occurrence and maximum wave heights. However, instrumental and written records commonly span too little time to reveal the full range of a region's tsunami hazard. The sedimentary deposits of tsunamis, identified with the aid of modern analogs, increasingly complement instrumental and human observations. By adding the component of tsunamis inferred from the geologic record, the Global Tsunami Database extends the record of tsunamis backward in time. Deposit locations, their estimated age and descriptions of the deposits themselves fill in the tsunami record. Tsunamis inferred from proxies, such as evidence for coseismic subsidence, are included to estimate recurrence intervals, but are flagged to highlight the absence of a physical deposit. Authors may submit their own descriptions and upload digital versions of publications. Users may sort by any populated field, including event, location, region, age of deposit, author, publication type (extract information from peer reviewed publications only, if you wish), grain size, composition, presence/absence of plant material. Users may find tsunami deposit references for a given location, event or author; search for particular properties of tsunami deposits; and even identify potential collaborators. Users may also download public-domain documents. Data and information may be viewed using tools designed to extract and display data from the Oracle database (selection forms, Web Map Services, and Web Feature Services). In addition, the historic tsunami archive (along with related earthquakes and volcanic eruptions) is available in KML (Keyhole Markup Language) format for use with Google Earth and similar geo-viewers.

Improvement of tsunami detection in timeseries data of GPS buoys with the Continuous Wavelet Transform

NASA Astrophysics Data System (ADS)

Chida, Y.; Takagawa, T.

2017-12-01

The observation data of GPS buoys which are installed in the offshore of Japan are used for monitoring not only waves but also tsunamis in Japan. The real-time data was successfully used to upgrade the tsunami warnings just after the 2011 Tohoku earthquake. Huge tsunamis can be easily detected because the signal-noise ratio is high enough, but moderate tsunami is not. GPS data sometimes include the error waveforms like tsunamis because of changing accuracy by the number and the position of GPS satellites. To distinguish the true tsunami waveforms from pseudo-tsunami ones is important for tsunami detection. In this research, a method to reduce misdetections of tsunami in the observation data of GPS buoys and to increase the efficiency of tsunami detection was developed.Firstly, the error waveforms were extracted by using the indexes of position dilution of precision, reliability of GPS satellite positioning and satellite number for calculation. Then, the output from this procedure was used for the Continuous Wavelet Transform (CWT) to analyze the time-frequency characteristics of error waveforms and real tsunami waveforms.We found that the error waveforms tended to appear when the accuracy of GPS buoys positioning was low. By extracting these waveforms, it was possible to decrease about 43% error waveforms without the reduction of the tsunami detection rate. Moreover, we found that the amplitudes of power spectra obtained from the error waveforms and real tsunamis were similar in the component of long period (4-65 minutes), on the other hand, the amplitude in the component of short period (< 1 minute) obtained from the error waveforms was significantly larger than that of the real tsunami waveforms. By thresholding of the short-period component, further extraction of error waveforms became possible without a significant reduction of tsunami detection rate.

Advancing our understanding of the onshore propagation of tsunami bores over rough surfaces through numerical modeling

NASA Astrophysics Data System (ADS)

Marras, S.; Suckale, J.; Eguzkitza, B.; Houzeaux, G.; Vázquez, M.; Lesage, A. C.

2016-12-01

The propagation of tsunamis in the open ocean has been studied in detail with many excellent numerical approaches available to researchers. Our understanding of the processes that govern the onshore propagation of tsunamis is less advanced. Yet, the reach of tsunamis on land is an important predictor of the damage associated with a given event, highlighting the need to investigate the factors that govern tsunami propagation onshore. In this study, we specifically focus on understanding the effect of bottom roughness at a variety of scales. The term roughness is to be understood broadly, as it represents scales ranging from small features like rocks, to vegetation, up to the size of larger structures and topography. In this poster, we link applied mathematics, computational fluid dynamics, and tsunami physics to analyze the small scales features of coastal hydrodynamics and the effect of roughness on the motion of tsunamis as they run up a sloping beach and propagate inland. We solve the three-dimensional Navier-Stokes equations of incompressible flows with free surface, which is tracked by a level set function in combination with an accurate re-distancing scheme. We discretize the equations via linear finite elements for space approximation and fully implicit time integration. Stabilization is achieved via the variational multiscale method whereas the subgrid scales for our large eddy simulations are modeled using a dynamically adaptive Smagorinsky eddy viscosity. As the geometrical characteristics of roughness in this study vary greatly across different scales, we implement a scale-dependent representation of the roughness elements. We model the smallest sub-grid scale roughness features by the use of a properly defined law of the wall. Furthermore, we utilize a Manning formula to compute the shear stress at the boundary. As the geometrical scales become larger, we resolve the geometry explicitly and compute the effective volume drag introduced by large scale immersed bodies. This study is a necessary step to verify and validate our model before proceeding further into the simulation of sediment transport in turbulent free surface flows. The simulation of such problems requires a space and time-dependent viscosity to model the effect of solid bodies transported by the incoming flow on onshore tsunami propagation.

What Causes Tsunamis?

ERIC Educational Resources Information Center

Mogil, H. Michael

2005-01-01

On December 26, 2004, a disastrous tsunami struck many parts of South Asia. The scope of this disaster has resulted in an outpouring of aid throughout the world and brought attention to the science of tsunamis. "Tsunami" means "harbor wave" in Japanese, and the Japanese have a long history of tsunamis. The word…

Introduction to “Global tsunami science: Past and future, Volume II”

USGS Publications Warehouse

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2017-01-01

Twenty-two papers on the study of tsunamis are included in Volume II of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 (Eds., E. L. Geist, H. M. Fritz, A. B. Rabinovich, and Y. Tanioka). Three papers in Volume II focus on details of the 2011 and 2016 tsunami-generating earthquakes offshore of Tohoku, Japan. The next six papers describe important case studies and observations of recent and historical events. Four papers related to tsunami hazard assessment are followed by three papers on tsunami hydrodynamics and numerical modelling. Three papers discuss problems of tsunami warning and real-time forecasting. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: volcanic explosions, landslides, and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Tsunami Preparedness in California (videos)

USGS Publications Warehouse

Filmed and edited by: Loeffler, Kurt; Gesell, Justine

2010-01-01

Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the West coast of the United States, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training. These videos about tsunami preparedness in California distinguish between a local tsunami and a distant event and focus on the specific needs of each region. They offer guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings, who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis. These videos were produced by the U.S. Geological Survey (USGS) in cooperation with the California Emergency Management Agency (CalEMA) and Pacific Gas and Electric Company (PG&E).

Tsunami Preparedness in Oregon (video)

USGS Publications Warehouse

Filmed and edited by: Loeffler, Kurt; Gesell, Justine

2010-01-01

Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the West coast of the United States, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training. This video about tsunami preparedness in Oregon distinguishes between a local tsunami and a distant event and focus on the specific needs of this region. It offers guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings, who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis. This video was produced by the US Geological Survey (USGS) in cooperation with Oregon Department of Geology and Mineral Industries (DOGAMI).

Introduction to "Global Tsunami Science: Past and Future, Volume II"

NASA Astrophysics Data System (ADS)

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2017-08-01

Twenty-two papers on the study of tsunamis are included in Volume II of the PAGEOPH topical issue "Global Tsunami Science: Past and Future". Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 (Eds., E. L. Geist, H. M. Fritz, A. B. Rabinovich, and Y. Tanioka). Three papers in Volume II focus on details of the 2011 and 2016 tsunami-generating earthquakes offshore of Tohoku, Japan. The next six papers describe important case studies and observations of recent and historical events. Four papers related to tsunami hazard assessment are followed by three papers on tsunami hydrodynamics and numerical modelling. Three papers discuss problems of tsunami warning and real-time forecasting. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: volcanic explosions, landslides, and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

The 15 August 2007 Peru tsunami runup observations and modeling

NASA Astrophysics Data System (ADS)

Fritz, Hermann M.; Kalligeris, Nikos; Borrero, Jose C.; Broncano, Pablo; Ortega, Erick

2008-05-01

On 15 August 2007 an earthquake with moment magnitude (Mw) of 8.0 centered off the coast of central Peru, generated a tsunami with locally focused runup heights of up to10 m. A reconnaissance team was deployed two weeks after the event and investigated the tsunami effects at 51 sites. Three tsunami fatalities were reported south of the Paracas Peninsula in a sparsely populated desert area where the largest tsunami runup heights were measured. Numerical modeling of the earthquake source and tsunami suggest that a region of high slip near the coastline was primarily responsible for the extreme runup heights. The town of Pisco was spared by the Paracas Peninsula, which blocked tsunami waves from propagating northward from the high slip region. The coast of Peru has experienced numerous deadly and destructive tsunamis throughout history, which highlights the importance of ongoing tsunami awareness and education efforts to ensure successful self-evacuation.

Mechanism of the 2015 volcanic tsunami earthquake near Torishima, Japan

PubMed Central

Satake, Kenji

2018-01-01

Tsunami earthquakes are a group of enigmatic earthquakes generating disproportionally large tsunamis relative to seismic magnitude. These events occur most typically near deep-sea trenches. Tsunami earthquakes occurring approximately every 10 years near Torishima on the Izu-Bonin arc are another example. Seismic and tsunami waves from the 2015 event [Mw (moment magnitude) = 5.7] were recorded by an offshore seafloor array of 10 pressure gauges, ~100 km away from the epicenter. We made an array analysis of dispersive tsunamis to locate the tsunami source within the submarine Smith Caldera. The tsunami simulation from a large caldera-floor uplift of ~1.5 m with a small peripheral depression yielded waveforms remarkably similar to the observations. The estimated central uplift, 1.5 m, is ~20 times larger than that inferred from the seismologically determined non–double-couple source. Thus, the tsunami observation is not compatible with the published seismic source model taken at face value. However, given the indeterminacy of Mzx, Mzy, and M{tensile} of a shallow moment tensor source, it may be possible to find a source mechanism with efficient tsunami but inefficient seismic radiation that can satisfactorily explain both the tsunami and seismic observations, but this question remains unresolved. PMID:29740604

Mechanism of the 2015 volcanic tsunami earthquake near Torishima, Japan.

PubMed

Fukao, Yoshio; Sandanbata, Osamu; Sugioka, Hiroko; Ito, Aki; Shiobara, Hajime; Watada, Shingo; Satake, Kenji

2018-04-01

Tsunami earthquakes are a group of enigmatic earthquakes generating disproportionally large tsunamis relative to seismic magnitude. These events occur most typically near deep-sea trenches. Tsunami earthquakes occurring approximately every 10 years near Torishima on the Izu-Bonin arc are another example. Seismic and tsunami waves from the 2015 event [ M w (moment magnitude) = 5.7] were recorded by an offshore seafloor array of 10 pressure gauges, ~100 km away from the epicenter. We made an array analysis of dispersive tsunamis to locate the tsunami source within the submarine Smith Caldera. The tsunami simulation from a large caldera-floor uplift of ~1.5 m with a small peripheral depression yielded waveforms remarkably similar to the observations. The estimated central uplift, 1.5 m, is ~20 times larger than that inferred from the seismologically determined non-double-couple source. Thus, the tsunami observation is not compatible with the published seismic source model taken at face value. However, given the indeterminacy of M zx , M zy , and M {tensile} of a shallow moment tensor source, it may be possible to find a source mechanism with efficient tsunami but inefficient seismic radiation that can satisfactorily explain both the tsunami and seismic observations, but this question remains unresolved.

Immediate Ecological Impacts of the 2011 Tohoku Earthquake Tsunami on Intertidal Flat Communities

PubMed Central

Urabe, Jotaro; Suzuki, Takao; Nishita, Tatsuki; Makino, Wataru

2013-01-01

Following the Great East Japan Earthquake in 2011, a large tsunami developed and struck the Pacific coast of eastern Japan. To assess the immediate impacts of the tsunami on coastal communities, changes in taxon composition and richness of macrobenthic animals before and after the tsunami were examined at nine intertidal flats in Sendai Bay and the Sanriku Ria coast. The results showed that 30–80% of taxa indigenously inhabiting intertidal flats disappeared after the tsunami. Among animal types, endobenthic and sessile epibenthic animals were more vulnerable to the tsunami than mobile epibenthic animals like shore crabs and snails. For all the intertidal flats examined, animals that were originally dwellers in lower tidal zones and not recorded before the tsunami were also found right after the tsunami, indicating that the tsunami not only took away many benthic taxa from the intertidal flats but also brought in some taxa from elsewhere. However, overall changes in taxon community composition were greater for intertidal flats that experienced larger inundation heights. These results showed that the ecological impacts of the tsunami were proportional to the physical impacts as gauged by wave height and that mobile epibenthic animals were less vulnerable to the tsunami. PMID:23650529

Immediate ecological impacts of the 2011 Tohoku earthquake tsunami on intertidal flat communities.

PubMed

Urabe, Jotaro; Suzuki, Takao; Nishita, Tatsuki; Makino, Wataru

2013-01-01

Following the Great East Japan Earthquake in 2011, a large tsunami developed and struck the Pacific coast of eastern Japan. To assess the immediate impacts of the tsunami on coastal communities, changes in taxon composition and richness of macrobenthic animals before and after the tsunami were examined at nine intertidal flats in Sendai Bay and the Sanriku Ria coast. The results showed that 30-80% of taxa indigenously inhabiting intertidal flats disappeared after the tsunami. Among animal types, endobenthic and sessile epibenthic animals were more vulnerable to the tsunami than mobile epibenthic animals like shore crabs and snails. For all the intertidal flats examined, animals that were originally dwellers in lower tidal zones and not recorded before the tsunami were also found right after the tsunami, indicating that the tsunami not only took away many benthic taxa from the intertidal flats but also brought in some taxa from elsewhere. However, overall changes in taxon community composition were greater for intertidal flats that experienced larger inundation heights. These results showed that the ecological impacts of the tsunami were proportional to the physical impacts as gauged by wave height and that mobile epibenthic animals were less vulnerable to the tsunami.

Assessment of a Tsunami Hazard for Mediterranean Coast of Egypt

NASA Astrophysics Data System (ADS)

Zaytsev, Andrey; Babeyko, Andrey; Yalciner, Ahmet; Pelinovsky, Efim

2017-04-01

Analysis of tsunami hazard for Egypt based on historic data and numerical modelling of historic and prognostic events is given. There are 13 historic events for 4000 years, including one instrumental record (1956). Tsunami database includes 12 earthquake tsunamis and 1 event of volcanic origin (Santorini eruption). Tsunami intensity of events (365, 881, 1303, 1870) is estimated as I = 3 led to tsunami wave height more than 6 m. Numerical simulation of some possible scenario of tsunamis of seismic and landslide origin is done with use of NAMI-DANCE software solved the shallow-water equations. The PTHA method (Probabilistic Tsunami Hazard Assessment - Probabilistic assessment of a tsunami hazard) for the Mediterranean Sea developed in (Sorensen M.B., Spada M., Babeyko A., Wiemer S., Grunthal G. Probabilistic tsunami hazard in the Mediterranean Sea. J Geophysical Research, 2012, vol. 117, B01305) is used to evaluate the probability of tsunami occurrence on the Egyptian coast. The synthetic catalogue of prognostic tsunamis of seismic origin with magnitude more than 6.5 includes 84 920 events for 100000 years. For the wave heights more 1 m the curve: exceedance probability - tsunami height can be approximated by exponential Gumbel function with two parameters which are determined for each coastal location in Egypt (totally. 24 points). Prognostic extreme highest events with probability less 10-4 are not satisfied to the Gumbel function (approximately 10 events) and required the special analysis. Acknowledgements: This work was supported EU FP7 ASTARTE Project [603839], and for EP - NS6637.2016.5.

New Measurements and Modeling Capability to Improve Real-time Forecast of Cascadia Tsunamis along U.S. West Coast

NASA Astrophysics Data System (ADS)

Wei, Y.; Titov, V. V.; Bernard, E. N.; Spillane, M. C.

2014-12-01

The tragedies of 2004 Sumatra and 2011 Tohoku tsunamis exposed the limits of our knowledge in preparing for devastating tsunamis, especially in the near field. The 1,100-km coastline of the Pacific coast of North America has tectonic and geological settings similar to Sumatra and Japan. The geological records unambiguously show that the Cascadia fault had caused devastating tsunamis in the past and this geological process will cause tsunamis in the future. Existing observational instruments along the Cascadia Subduction Zone are capable of providing tsunami data within minutes of tsunami generation. However, this strategy requires separation of the tsunami signals from the overwhelming high-frequency seismic waves produced during a strong earthquake- a real technical challenge for existing operational tsunami observational network. A new-generation of nano-resolution pressure sensors can provide high temporal resolution of the earthquake and tsunami signals without loosing precision. The nano-resolution pressure sensor offers a state-of the-science ability to separate earthquake vibrations and other oceanic noise from tsunami waveforms, paving the way for accurate, early warnings of local tsunamis. This breakthrough underwater technology has been tested and verified for a couple of micro-tsunami events (Paros et al., 2011). Real-time forecast of Cascadia tsunamis is becoming a possibility with the development of nano-tsunameter technology. The present study provides an investigation on optimizing the placement of these new sensors so that the forecast time can be shortened.. The presentation will cover the optimization of an observational array to quickly detect and forecast a tsunami generated by a strong Cascadia earthquake, including short and long rupture scenarios. Lessons learned from the 2011 Tohoku tsunami will be examined to demonstrate how we can improve the local forecast using the new technology We expect this study to provide useful guideline for future siting and deployment of the new-generation tsunameters. Driven by the new technology, we demonstrate scenarios of real-time forecast of Cascadia tsunami impact along the Pacific Northwest, as well as in the Puget Sound.

Reducing the age range of tsunami deposits by 14C dating of rip-up clasts

NASA Astrophysics Data System (ADS)

Ishizawa, Takashi; Goto, Kazuhisa; Yokoyama, Yusuke; Miyairi, Yosuke; Sawada, Chikako; Takada, Keita

2018-02-01

Erosion by tsunami waves represents an important issue when determining the age of a tsunami deposit, because the age is usually estimated using dating of sediments above and below the deposit. Dating of material within the tsunami deposit, if suitable material is obtainable, can be used to further constrain its age. Eroded sediments are sometimes incorporated within the tsunami deposits as rip-up clasts, which might therefore be used as minimum age dating material. However, the single calibrated 14C age often shows a wide age range because of fluctuations in the calibration curve. Therefore, it remains uncertain whether rip-up clast measurements are useful to constrain the depositional age of tsunami deposits, or not. In this study, we carried out high-resolution 14C dating of tsunami deposits, including rip-up clasts of peat, in Rikuzentakata, northeastern Japan, where numerous rip-up clasts were observed within a tsunami deposit. Sediments above and below the tsunami deposit and a 5 cm large rip-up clast were dated sequentially. Comparison of these dating results with the calibration curve revealed that the clast was inverted. Its age was better constrained based on the stratigraphic order, and we infer that the clast corresponds to approximately 100 years of sedimentation. The oldest age of the clast was consistent with the age of the peat immediately below the tsunami deposit, suggesting that surface sediments probably formed the rip-up clast at the time of the tsunami. Thus, the dating of the rip-up clast was useful to further constrain the depositional age of the tsunami deposit, as we narrowed the tsunami deposit age range by approximately 100 years. Results show that ignoring tsunami-related erosion might lead to overestimation of the tsunami deposit age. For this reason, an appropriate dating site, which is less affected by minor tsunami-related erosion with regards to the paleo-topography, should be explored. We therefore propose a more effective sampling strategy for better age estimation of tsunami deposits.

Multiple indices method for real-time tsunami inundation forecast using a dense offshore observation network

NASA Astrophysics Data System (ADS)

Yamamoto, N.; Aoi, S.; Hirata, K.; Suzuki, W.; Kunugi, T.; Nakamura, H.

2015-12-01

We started to develop a new methodology for real-time tsunami inundation forecast system (Aoi et al., 2015, this meeting) using densely offshore tsunami observations of the Seafloor Observation Network for Earthquakes and Tsunamis (S-net), which is under construction along the Japan Trench (Kanazawa et al., 2012, JpGU; Uehira et al., 2015, IUGG). In our method, the most important concept is involving any type and/or form uncertainties in the tsunami forecast, which cannot be dealt with any of standard linear/nonlinear least square approaches. We first prepare a Tsunami Scenario Bank (TSB), which contains offshore tsunami waveforms at the S-net stations and tsunami inundation information calculated from any possible tsunami source. We then quickly select several acceptable tsunami scenarios that can explain offshore observations by using multiple indices and appropriate thresholds, after a tsunami occurrence. At that time, possible tsunami inundations coupled with selected scenarios are forecasted (Yamamoto et al., 2014, AGU). Currently, we define three indices: correlation coefficient and two variance reductions, whose L2-norm part is normalized either by observations or calculations (Suzuki et al., 2015, JpGU; Yamamoto et al., 2015, IUGG). In this study, we construct the TSB, which contains various tsunami source models prepared for the probabilistic tsunami hazard assessment in the Japan Trench region (Hirata et al., 2014, AGU). To evaluate the propriety of our method, we adopt the fault model based on the 2011 Tohoku earthquake as a pseudo "observation". We also calculate three indices using coastal maximum tsunami height distributions between observation and calculation. We then obtain the correlation between coastal and offshore indices. We notice that the index value of coastal maximum tsunami heights is closer to 1 than the index value of offshore waveforms, i.e., the coastal maximum tsunami height may be predictable within appropriate thresholds defined for offshore indices. We also investigate the effect of rise-time. This work was partially supported by the Council for Science, Technology and Innovation (CSTI) through the Cross-ministerial Strategic Innovation Promotion Program (SIP), titled "Enhancement of societal resiliency against natural disasters" (Funding agency: JST).

Tsunami normal modes with solid earth and atmospheric coupling and inversion of the TEC data to estimate tsunami water height in the case of the Queen Charlotte tsunami.

NASA Astrophysics Data System (ADS)

Rakoto, V.; Lognonne, P. H.; Rolland, L.

2016-12-01

Large underwater earthquakes (Mw > 7) can transmit part of their energy to the surrounding ocean through large sea-floor motions, generating tsunamis that propagate over long distances. The forcing effect of long period ocean surface vibrations due to tsunami waves on the atmosphere trigger atmospheric internal gravity waves (IGWs) that induce ionospheric disturbances when they reach the upper atmosphere. In this poster, we study the IGWs associated to tsunamis using a normal modes 1D modeling approach. Our model is first applied to the case of the October 2012 Haida Gwaii tsunami observed offshore Hawaii. We found three resonances between tsunami modes and the atmospheric gravity modes occurring around 1.5 mHz, 2 mHz and 2.5 mHz, with a large fraction of the energy of the tsunami modes transferred from the ocean to the atmosphere. At theses frequencies, the gravity branches are interacting with the tsunami one and have large amplitude in the ocean. As opposed to the tsunami, a fraction of their energy is therefore transferred from the atmosphere to the ocean. We also show that the fundamental of the gravity waves should arrive before the tsunami due to higher group velocity below 1.6 mHz. We demonstrate that only the 1.5 mHz resonance of the tsunami mode can trigger observable ionospheric perturbations, most often monitored using GPS dual-frequency measurements. Indeed, we show that the modes at 2 mHz and 2.5 mHz are already evanescent at the height of the F2 peak and have little energy in the ionosphere. This normal modes modeling offers a novel and comprehensive study of the transfer function from a propagating tsunami to the upper atmosphere. In particular, we can invert the perturbed TEC data induced by a tsunami in order to estimate the amplitude of the tsunami waveform using a least square method. This method has been performed in the case of the Haida Gwaii tsunami. The results showed a good agreement with the measurement of the dart buoy.

Using GPS to Detect Imminent Tsunamis

NASA Technical Reports Server (NTRS)

Song, Y. Tony

2009-01-01

A promising method of detecting imminent tsunamis and estimating their destructive potential involves the use of Global Positioning System (GPS) data in addition to seismic data. Application of the method is expected to increase the reliability of global tsunami-warning systems, making it possible to save lives while reducing the incidence of false alarms. Tsunamis kill people every year. The 2004 Indian Ocean tsunami killed about 230,000 people. The magnitude of an earthquake is not always a reliable indication of the destructive potential of a tsunami. The 2004 Indian Ocean quake generated a huge tsunami, while the 2005 Nias (Indonesia) quake did not, even though both were initially estimated to be of the similar magnitude. Between 2005 and 2007, five false tsunami alarms were issued worldwide. Such alarms result in negative societal and economic effects. GPS stations can detect ground motions of earthquakes in real time, as frequently as every few seconds. In the present method, the epicenter of an earthquake is located by use of data from seismometers, then data from coastal GPS stations near the epicenter are used to infer sea-floor displacements that precede a tsunami. The displacement data are used in conjunction with local topographical data and an advanced theory to quantify the destructive potential of a tsunami on a new tsunami scale, based on the GPS-derived tsunami energy, much like the Richter Scale used for earthquakes. An important element of the derivation of the advanced theory was recognition that horizontal sea-floor motions contribute much more to generation of tsunamis than previously believed. The method produces a reliable estimate of the destructive potential of a tsunami within minutes typically, well before the tsunami reaches coastal areas. The viability of the method was demonstrated in computational tests in which the method yielded accurate representations of three historical tsunamis for which well-documented ground-motion measurements were available. Development of a global tsunami-warning system utilizing an expanded network of coastal GPS stations was under consideration at the time of reporting the information for this article.

First application of tsunami back-projection and source inversion for the 2012 Haida Gwaii earthquake using tsunami data recorded on a dense array of seafloor pressure gauges

NASA Astrophysics Data System (ADS)

Gusman, A. R.; Satake, K.; Sheehan, A. F.; Mulia, I. E.; Heidarzadeh, M.; Maeda, T.

2015-12-01

Adaption of absolute or differential pressure gauges (APG or DPG) to Ocean Bottom Seismometers has provided the opportunity to study tsunamis. Recently we extracted tsunami waveforms of the 28 October 2012 Haida Gwaii earthquake recoded by the APG and DPG of Cascadia Initiative program (Sheehan et al., 2015, SRL). We applied such dense tsunami observations (48 stations) together with other records from DARTs (9 stations) to characterize the tsunami source. This study is the first study that used such a large number of offshore tsunami records for earthquake source study. Conventionally the curves of tsunami travel times are drawn backward from station locations to estimate the tsunami source region. Here we propose a more advanced technique called tsunami back-projection to estimate the source region. Our image produced by tsunami back-projection has the largest value or tsunami centroid that is very close to the epicenter and above the Queen Charlotte transform fault (QCF), whereas the negative values are mostly located east of Haida Gwaii in the Hecate Strait. By using tsunami back-projection we avoid picking initial tsunami phase which is a necessary step in the conventional method that is rather subjective. The slip distribution of the 2012 Haida Gwaii earthquake estimated by tsunami waveform inversion shows large slip near the trench (4-5 m) and also on a plate interface southeast the epicenter (3-4 m) below QCF. From the slip distribution, the calculated seismic moment is 5.4 × 1020 N m (Mw 7.8). The steep bathymetry offshore Haida Gwaii and the horizontal movement caused by the earthquake possibly affects the sea surface deformation. The potential tsunami energy calculated from the sea-surface deformation of pure faulting is 2.20 × 1013 J, while that from the bathymetry effect is 0.12 × 1013 J or about 5% of the total potential energy. The significant deformation above the steep slope is confirmed by another tsunami inversion that disregards fault parameters.

The Redwood Coast Tsunami Work Group: Promoting Earthquake and Tsunami Resilience on California's North Coast

NASA Astrophysics Data System (ADS)

Dengler, L. A.; Henderson, C.; Larkin, D.; Nicolini, T.; Ozaki, V.

2014-12-01

In historic times, Northern California has suffered the greatest losses from tsunamis in the U.S. contiguous 48 states. 39 tsunamis have been recorded in the region since 1933, including five that caused damage. This paper describes the Redwood Coast Tsunami Work Group (RCTWG), an organization formed in 1996 to address the tsunami threat from both near and far sources. It includes representatives from government agencies, public, private and volunteer organizations, academic institutions, and individuals interested in working to reduce tsunami risk. The geographic isolation and absence of scientific agencies such as the USGS and CGS in the region, and relatively frequent occurrence of both earthquakes and tsunami events has created a unique role for the RCTWG, with activities ranging from basic research to policy and education and outreach programs. Regional interest in tsunami issues began in the early 1990s when there was relatively little interest in tsunamis elsewhere in the state. As a result, the group pioneered tsunami messaging and outreach programs. Beginning in 2008, the RCTWG has partnered with the National Weather Service and the California Office of Emergency Services in conducting the annual "live code" tsunami communications tests, the only area outside of Alaska to do so. In 2009, the RCTWG joined with the Southern California Earthquake Alliance and the Bay Area Earthquake Alliance to form the Earthquake Country Alliance to promote a coordinated and consistent approach to both earthquake and tsunami preparedness throughout the state. The RCTWG has produced and promoted a variety of preparedness projects including hazard mapping and sign placement, an annual "Earthquake - Tsunami Room" at County Fairs, public service announcements and print material, assisting in TsunamiReady community recognition, and facilitating numerous multi-agency, multidiscipline coordinated exercises, and community evacuation drills. Nine assessment surveys from 1993 to 2013 have tracked preparedness actions and personal awareness of tsunami hazards. Over the twenty-year period covered by the surveys, respondents aware of a local tsunami hazard increased from 51 to 90 percent and awareness of the Cascadia subduction zone increased from 16 to 60 percent.

Non-Poissonian Distribution of Tsunami Waiting Times

NASA Astrophysics Data System (ADS)

Geist, E. L.; Parsons, T.

2007-12-01

Analysis of the global tsunami catalog indicates that tsunami waiting times deviate from an exponential distribution one would expect from a Poisson process. Empirical density distributions of tsunami waiting times were determined using both global tsunami origin times and tsunami arrival times at a particular site with a sufficient catalog: Hilo, Hawai'i. Most sources for the tsunamis in the catalog are earthquakes; other sources include landslides and volcanogenic processes. Both datasets indicate an over-abundance of short waiting times in comparison to an exponential distribution. Two types of probability models are investigated to explain this observation. Model (1) is a universal scaling law that describes long-term clustering of sources with a gamma distribution. The shape parameter (γ) for the global tsunami distribution is similar to that of the global earthquake catalog γ=0.63-0.67 [Corral, 2004]. For the Hilo catalog, γ is slightly greater (0.75-0.82) and closer to an exponential distribution. This is explained by the fact that tsunamis from smaller triggered earthquakes or landslides are less likely to be recorded at a far-field station such as Hilo in comparison to the global catalog, which includes a greater proportion of local tsunamis. Model (2) is based on two distributions derived from Omori's law for the temporal decay of triggered sources (aftershocks). The first is the ETAS distribution derived by Saichev and Sornette [2007], which is shown to fit the distribution of observed tsunami waiting times. The second is a simpler two-parameter distribution that is the exponential distribution augmented by a linear decay in aftershocks multiplied by a time constant Ta. Examination of the sources associated with short tsunami waiting times indicate that triggered events include both earthquake and landslide tsunamis that begin in the vicinity of the primary source. Triggered seismogenic tsunamis do not necessarily originate from the same fault zone, however. For example, subduction-thrust and outer-rise earthquake pairs are evident, such as the November 2006 and January 2007 Kuril Islands tsunamigenic pair. Because of variations in tsunami source parameters, such as water depth above the source, triggered tsunami events with short waiting times are not systematically smaller than the primary tsunami.

Research on stability of nozzle-floating plate institution

NASA Astrophysics Data System (ADS)

Huang, Bin; Tao, Jiayue; Yi, Jiajing; Chen, Shijing

2016-01-01

In this paper, air hammer instability of nozzle-floating plate institution in gas lubricated force sensor were studied. Through establishment of the theoretical model for the analysis of the nozzle-floating plate institution stability, combined with air hammer stability judgment theorems, we had some simulation research on the radius of the nozzle, the radius of the pressure chamber, pressure chamber depth, orifice radius and the relationship between air supply pressure and bearing capacity, in order to explore the instability mechanism of nozzle-floating plate institution. For conducting experimental observations for the stability of two groups nozzle-floating plate institution, which have typical structural parameters conducted experimental observations. We set up a special experimental device, verify the correctness of the theoretical study and simulation results. This paper shows that in the nozzle-floating plate institution, increasing the nozzle diameter, reduced pressure chamber radius, reducing the depth of the pressure chamber and increase the supply orifice radius, and other measures is conducive to system stability. Results of this study have important implications for research and design of gas lubricated force sensor.

The impact of the night float system on internal medicine residency programs.

PubMed

Trontell, M C; Carson, J L; Taragin, M I; Duff, A

1991-01-01

To study the design, method of implementation, perceived benefits, and problems associated with a night float system. Self-administered questionnaire completed by program directors, which included both structured and open-ended questions. The answers reflect resident and student opinions as well as those of the program directors, since program directors regularly obtain feedback from these groups. The 442 accredited internal medicine residency programs listed in the 1988-89 Directory of Graduate Medical Education Programs. Of the 442 programs, 79% responded, and 30% had experience with a night float system. The most frequent methods for initiating a night float system included: decreasing elective time (42.3%), hiring more residents (26.9%), creating a non-teaching service (12.5%), and reallocating housestaff time (9.6%). Positive effects cited include decreased fatigue, improved housestaff morale, improved recruiting, and better attitude toward internal medicine training. The quality of medical care was considered the same or better by most programs using it. The most commonly cited problems were decreased continuity of care, inadequate teaching of the night float team, and miscommunication. Residency programs using a night float system usually observe a positive effect on housestaff morale, recruitment, and working hours and no detrimental effect on the quality of patient care. Miscommunication and inadequate learning experience for the night float team are important potential problems. This survey suggests that the night float represents one solution to reducing resident working hours.

Back-arc basin opening and closure along the southern margin of the Sea of Japan

NASA Astrophysics Data System (ADS)

Sato, Hiroshi; Claringbould, Johan; Ishiyama, Tatsuya; Kato, Naoko; Abe, Susumu; Kawasaki, Shinji

2016-04-01

Following the tsunami disaster produced by 2001 Off-Tohoku earthquake (M9) along the Pacific coast of Japan, the Japanese government started an intense evaluation of tsunami hazards. This evaluation spanned along the full Japanese coast, including the Sea of Japan coast on the western side of the Japan arc. In the Sea of Japan, tsunamis are produced by crustal faults. As the longer interval of faulting activity, the historical records of tsunamis in the Sea of Japan are not enough for the evaluation of tsunami height. Thus, the evaluation is carried out based on structural analyses of the margin of the Sea of Japan. To get better understanding of the present-day structural geometry and develop a source-fault model in this region, intense seismic reflection profiling has been carried out since 2013. We introduce the results of the seismic reflection profiles and discuss the structural evolution of the southern margin of the Sea of Japan. 2D seismic reflection profiles were acquired using 1950 cu. in. air-gun and 2100 m streamer cable. The seismic profiles provide the image image up to 3 seconds TWT. The southern margin of the Sea of Japan was produced by back-arc opening and post-rift deformation, and the structural evolution of this area is divided into several stages: rifting (25 - 14 Ma), post-rift compression (14 - 5 Ma), weak thrusting (5 - 1 Ma), and strike-slip deformation (1 Ma to present). During the rifting stage that is associated with the fan-shaped opening of the Sea of Japan, grabens and half-grabens were formed trending parallel to the extension of SW-Japan arc. These grabens were filled by syn-rift sediments, and the maximum thickness of basin fill is observed along the southern margin of the rifted crust. The opening of the Sea of Japan ceased as a result of the collision of Izu-Bonin-Mariana arc system at the Izu collision zone on the central part of Honshu, Japan. Soon after the this event, the young Shikoku basin within the Philippine Sea plate (PHS) moved northward towards the Nankai trough on the southeastern side of the SW-Japan arc. Due to the high thermal regime of the Shikoku basin, the resistance along the Nankai trough was so large that shortening deformation occurred along in the failed marginal rift zone that was developed previously along the southern margin of the Sea of Japan. This resulted in the Shinji fold belt. After the start of the subduction of the Shikoku basin along the Nankai trough, the rate of shortening in the Shinji fold belt was decreased and the folded strata were covered by sub-horizontal Pliocene sediments. Reverse faulting of the arc-parallel faults from Pliocene to early Pleistocene along the small number of faults suggests that the compression from the Nankai trough still has been continued in this stage. A change in the direction of the motion of PHS at 1 Ma produced major change in stress regime from NS compression to EW compression in the back-arc. Following the change of stress regime, the former reverse faults reactivated as strike-slip faults. The structural evolution and inherited structure presented here provide essential information for constructing the tsunami source-fault model along southern margin of the Sea of Japan.

The search for geologic evidence of distant-source tsunamis using new field data in California: Chapter C in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

USGS Publications Warehouse

Wilson, Rick; Hemphill-Haley, Eileen; Jaffe, Bruce; Richmond, Bruce; Peters, Robert; Graehl, Nick; Kelsey, Harvey; Leeper, Robert; Watt, Steve; McGann, Mary; Hoirup, Don F.; Chagué-Goff, Catherine; Goff, James; Caldwell, Dylan; Loofbourrow, Casey

2014-01-01

A statewide assessment for geological evidence of tsunamis, primarily from distant-source events, found tsunami deposits at several locations, though evidence was absent at most locations evaluated. Several historical distant-source tsunamis, including the 1946 Aleutian, 1960 Chile, and 1964 Alaska events, caused inundation along portions of the northern and central California coast. Recent numerical tsunami modeling results identify the eastern Aleutian Islands subduction zone as the “worstcase” distant-source region, with the potential for causing tsunami runups of 7–10 m in northern and central California and 3–4 m in southern California. These model results, along with a review of historical topographic maps and past geotechnical evaluations, guided site selection for tsunami deposit surveys. A reconnaissance of 20 coastal marshlands was performed through site visits and coring of shallow surface sediments to determine if evidence for past tsunamis existed. Although conclusive evidence of tsunami deposits was not found at most of the sites evaluated, geologic evidence consistent with tsunami inundation was found at two locations: Three marshes in the Crescent City area and Pillar Point marsh near Half Moon Bay. Potential tsunami deposits were also evaluated at the Carpinteria Salt Marsh Reserve in Santa Barbara County. In Crescent City, deposits were ascribed to tsunamis on the basis of stratigraphic architecture, particle size, and microfossil content, and they were further assigned to the 1964 Alaska and 1700 Cascadia tsunamis on the basis of dating by cesium-137 and radiocarbon methods, respectively. The 1946 tsunami sand deposit was clearly identified throughout Pillar Point marsh, and one to two other similar but highly discontinuous sand layers were present within 0.5 m of the surface. A tsunami-origin interpretation for sand layers at Carpinteria is merely consistent with graded bedding and unsupported by diatom or foraminiferal assemblages. Additional studies, including age dating, grain-size, and microfossil analyses are underway for the deposits at Crescent City, Pillar Point marsh, and Carpinteria, which may help further identify if other tsunami deposits exist at those sites. The absence of evidence for tsunamis at other sites examined should not preclude further work beyond the reconnaissance-level investigations at those locations.

A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

NASA Technical Reports Server (NTRS)

Edmonds, L. D.

2016-01-01

Since advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

NASA Technical Reports Server (NTRS)

Edmonds, L. D.

2016-01-01

Because advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

14 CFR 25.527 - Hull and main float load factors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and main float load factors. 25.527... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.527 Hull and main... 1=empirical hull station weighing factor, in accordance with figure 2 of appendix B. (7) r x=ratio...

Using Interdisciplinary Research Methods to Revise and Strengthen the NWS TsunamiReadyTM Community Recognition Program

NASA Astrophysics Data System (ADS)

Scott, C.; Gregg, C. E.; Ritchie, L.; Stephen, M.; Farnham, C.; Fraser, S. A.; Gill, D.; Horan, J.; Houghton, B. F.; Johnson, V.; Johnston, D.

2013-12-01

The National Tsunami Hazard Mitigation Program (NTHMP) partnered with the National Weather Service (NWS) in early 2000 to create the TsunamiReadyTM Community Recognition program. TsunamiReadyTM, modeled after the older NWS StormReadyTM program, is designed to help cities, towns, counties, universities and other large sites in coastal areas reduce the potential for disastrous tsunami-related consequences. To achieve TsunamiReadyTM recognition, communities must meet certain criteria aimed at better preparing a community for tsunami, including specific actions within the following categories: communications and coordination, tsunami warning reception, local warning dissemination, community preparedness, and administration. Using multidisciplinary research methods and strategies from Public Health; Psychology; Political, Social and Physical Sciences and Evaluation, our research team is working directly with a purposive sample of community stakeholders in collaboration and feedback focus group sessions. Invitation to participate is based on a variety of factors including but not limited to an individual's role as a formal or informal community leader (e.g., in business, government, civic organizations), or their organization or agency affiliation to emergency management and response. Community organizing and qualitative research methods are being used to elicit discussion regarding TsunamiReadyTM requirements and the division of requirements based on some aspect of tsunami hazard, vulnerability and risk, such as proximity to active or passive plate margins or subduction zone generated tsunamis versus earthquake-landslide generated tsunamis . The primary aim of this research is to use social science to revise and refine the NWS TsunamiReadyTM Guidelines in an effort to better prepare communities to reduce risk to tsunamis.

Tsunami magnetic signals in the Northwestern Pacific seafloor magnetic measurements

NASA Astrophysics Data System (ADS)

Schnepf, N. R.; An, C.; Nair, M. C.; Maus, S.

2013-12-01

In the past two decades, underwater cables and seafloor magnetometers have observed motional inductance from ocean tsunamis. This study aimed to characterize the electromagnetic signatures of tsunamis from seafloor stations to assist in the long-term goal of real-time tsunami detection and warning systems. Four ocean seafloor stations (T13, T14, T15, T18) in the Northeastern Philippine Sea collected vector measurements of the electric and magnetic fields every minute during the period of 10/05/2005 to 11/30/2007 (Baba et al., 2010 PEPI). During this time, four major tsunamis occurred as a result of moment magnitude 8.0-8.1 earthquakes. These tsunamis include the 05/03/2006 Tonga event, the 01/13/2007 Kuril Islands event, the 04/01/2007 Solomon Islands event, and the 08/15/2007 Peru event. The Cornell Multi-grid Coupled Tsunami model (COMCOT) was used to predict the arrival time of the tsunamis at each of the seafloor stations. The stations' raw magnetic field signals underwent a high pass filter to then be examined for signals of the tsunami arrival. The high pass filtering showed clear tsunami signals for the Tonga event, but a clear signal was not seen for the other events. This may be due to signals from near Earth space with periods similar to tsunamis. To remove extraneous atmospheric magnetic signals, a cross-wavelet analysis was conducted using the horizontal field components from three INTERMAGNET land stations and the vertical component from the seafloor stations. The cross-wavelet analysis showed that for three of the six stations (two of the four tsunami events) the peak in wavelet amplitude matched the arrival of the tsunami. We discuss implications of our finding in magnetic monitoring of tsunamis.

The UBO-TSUFD tsunami inundation model: validation and application to a tsunami case study focused on the city of Catania, Italy

NASA Astrophysics Data System (ADS)

Tinti, S.; Tonini, R.

2013-07-01

Nowadays numerical models are a powerful tool in tsunami research since they can be used (i) to reconstruct modern and historical events, (ii) to cast new light on tsunami sources by inverting tsunami data and observations, (iii) to build scenarios in the frame of tsunami mitigation plans, and (iv) to produce forecasts of tsunami impact and inundation in systems of early warning. In parallel with the general recognition of the importance of numerical tsunami simulations, the demand has grown for reliable tsunami codes, validated through tests agreed upon by the tsunami community. This paper presents the tsunami code UBO-TSUFD that has been developed at the University of Bologna, Italy, and that solves the non-linear shallow water (NSW) equations in a Cartesian frame, with inclusion of bottom friction and exclusion of the Coriolis force, by means of a leapfrog (LF) finite-difference scheme on a staggered grid and that accounts for moving boundaries to compute sea inundation and withdrawal at the coast. Results of UBO-TSUFD applied to four classical benchmark problems are shown: two benchmarks are based on analytical solutions, one on a plane wave propagating on a flat channel with a constant slope beach; and one on a laboratory experiment. The code is proven to perform very satisfactorily since it reproduces quite well the benchmark theoretical and experimental data. Further, the code is applied to a realistic tsunami case: a scenario of a tsunami threatening the coasts of eastern Sicily, Italy, is defined and discussed based on the historical tsunami of 11 January 1693, i.e. one of the most severe events in the Italian history.

Tsunami Data and Scientific Data Diplomacy

NASA Astrophysics Data System (ADS)

Arcos, N. P.; Dunbar, P. K.; Gusiakov, V. K.; Kong, L. S. L.; Aliaga, B.; Yamamoto, M.; Stroker, K. J.

2016-12-01

Free and open access to data and information fosters scientific progress and can build bridges between nations even when political relationships are strained. Data and information held by one stakeholder may be vital for promoting research of another. As an emerging field of inquiry, data diplomacy explores how data-sharing helps create and support positive relationships between countries to enable the use of data for societal and humanitarian benefit. Tsunami has arguably been the only natural hazard that has been addressed so effectively at an international scale and illustrates the success of scientific data diplomacy. Tsunami mitigation requires international scientific cooperation in both tsunami science and technology development. This requires not only international agreements, but working-level relationships between scientists from countries that may have different political and economic policies. For example, following the Pacific wide tsunami of 1960 that killed two thousand people in Chile and then, up to a day later, hundreds in Hawaii, Japan, and the Philippines; delegates from twelve countries met to discuss and draft the requirements for an international tsunami warning system. The Pacific Tsunami Warning System led to the development of local, regional, and global tsunami databases and catalogs. For example, scientists at NOAA/NCEI and the Tsunami Laboratory/Russian Academy of Sciences have collaborated on their tsunami catalogs that are now routinely accessed by scientists and the public around the world. These data support decision-making during tsunami events, are used in developing inundation and evacuation maps, and hazard assessments. This presentation will include additional examples of agreements for data-sharing between countries, as well as challenges in standardization and consistency among the tsunami research community. Tsunami data and scientific data diplomacy have ultimately improved understanding of tsunami and associated impacts.

Deposition by the 2011 Tohoku-oki tsunami on coastal lowland controlled by beach ridges near Sendai, Japan

NASA Astrophysics Data System (ADS)

Takashimizu, Yasuhiro; Urabe, Atsushi; Suzuki, Koji; Sato, Yoshiki

2012-12-01

A study of the 2011 Tohoku-oki tsunami deposits on the coastal lowland of the Sendai Plain, Japan was carried out along a shore-perpendicular survey line in the Arahama area. Field descriptions and tsunami water depth measurements were complemented by sedimentary analyses, including grain size, grain fabric and diatom analysis. The tsunami deposits show a generally fining-inland trend along the 3.4 km long transect. The depositional facies, grain size analysis and grain fabric data suggest that most of the tsunami deposits were laid down during the tsunami inflow, except at one site. These tsunami deposits are characterized by parallel-laminated or massive sand and silt with pieces of woods, fragments of glass, rip-up mud clasts and an erosional base. Minor backwash deposits overlying the inflow sand layer were only observed on one beach ridge and attributed to the topographic high. Marine diatom species comprised only approximately 2% of the diatom assemblage in tsunami deposits and their content decreased landward. In this study, diatom assemblages were similar in the rice field soil and tsunami layers, suggesting that the muddy fraction of the deposits mainly consists of sediments derived from the tsunami-eroded rice field soil. As a result of soil erosion, the tsunami had a high suspended sediment load. Furthermore, after the first tsunami inundation, seawater left by the tsunami did not drain completely to the sea because of the high coastal beach ridge and/or coastal subsidence due to the massive earthquake. Therefore, strong tsunami outflows to the sea did not occur and these areas were covered by mud deposited from stagnant water.

Assessing historical rate changes in global tsunami occurrence

USGS Publications Warehouse

Geist, E.L.; Parsons, T.

2011-01-01

The global catalogue of tsunami events is examined to determine if transient variations in tsunami rates are consistent with a Poisson process commonly assumed for tsunami hazard assessments. The primary data analyzed are tsunamis with maximum sizes >1m. The record of these tsunamis appears to be complete since approximately 1890. A secondary data set of tsunamis >0.1m is also analyzed that appears to be complete since approximately 1960. Various kernel density estimates used to determine the rate distribution with time indicate a prominent rate change in global tsunamis during the mid-1990s. Less prominent rate changes occur in the early- and mid-20th century. To determine whether these rate fluctuations are anomalous, the distribution of annual event numbers for the tsunami catalogue is compared to Poisson and negative binomial distributions, the latter of which includes the effects of temporal clustering. Compared to a Poisson distribution, the negative binomial distribution model provides a consistent fit to tsunami event numbers for the >1m data set, but the Poisson null hypothesis cannot be falsified for the shorter duration >0.1m data set. Temporal clustering of tsunami sources is also indicated by the distribution of interevent times for both data sets. Tsunami event clusters consist only of two to four events, in contrast to protracted sequences of earthquakes that make up foreshock-main shock-aftershock sequences. From past studies of seismicity, it is likely that there is a physical triggering mechanism responsible for events within the tsunami source 'mini-clusters'. In conclusion, prominent transient rate increases in the occurrence of global tsunamis appear to be caused by temporal grouping of geographically distinct mini-clusters, in addition to the random preferential location of global M >7 earthquakes along offshore fault zones.

Differences in tsunami generation between the December 26, 2004 and March 28, 2005 Sumatra earthquakes

USGS Publications Warehouse

Geist, E.L.; Bilek, S.L.; Arcas, D.; Titov, V.V.

2006-01-01

Source parameters affecting tsunami generation and propagation for the Mw > 9.0 December 26, 2004 and the Mw = 8.6 March 28, 2005 earthquakes are examined to explain the dramatic difference in tsunami observations. We evaluate both scalar measures (seismic moment, maximum slip, potential energy) and finite-source repre-sentations (distributed slip and far-field beaming from finite source dimensions) of tsunami generation potential. There exists significant variability in local tsunami runup with respect to the most readily available measure, seismic moment. The local tsunami intensity for the December 2004 earthquake is similar to other tsunamigenic earthquakes of comparable magnitude. In contrast, the March 2005 local tsunami was deficient relative to its earthquake magnitude. Tsunami potential energy calculations more accurately reflect the difference in tsunami severity, although these calculations are dependent on knowledge of the slip distribution and therefore difficult to implement in a real-time system. A significant factor affecting tsunami generation unaccounted for in these scalar measures is the location of regions of seafloor displacement relative to the overlying water depth. The deficiency of the March 2005 tsunami seems to be related to concentration of slip in the down-dip part of the rupture zone and the fact that a substantial portion of the vertical displacement field occurred in shallow water or on land. The comparison of the December 2004 and March 2005 Sumatra earthquakes presented in this study is analogous to previous studies comparing the 1952 and 2003 Tokachi-Oki earthquakes and tsunamis, in terms of the effect slip distribution has on local tsunamis. Results from these studies indicate the difficulty in rapidly assessing local tsunami runup from magnitude and epicentral location information alone.

Fatigue analysis of assembled marine floating platform for special purposes under complex water environments

NASA Astrophysics Data System (ADS)

Ma, Guang-ying; Yao, Yun-long

2018-03-01

In this paper, the fatigue lives of a new type of assembled marine floating platform for special purposes were studied. Firstly, by using ANSYS AQWA software, the hydrodynamic model of the platform was established. Secondly, the structural stresses under alternating change loads were calculated under complex water environments, such as wind, wave, current and ice. The minimum fatigue lives were obtained under different working conditions. The analysis results showed that the fatigue life of the platform structure can meet the requirements

Probabilistic tsunami hazard analysis: Multiple sources and global applications

USGS Publications Warehouse

Grezio, Anita; Babeyko, Andrey; Baptista, Maria Ana; Behrens, Jörn; Costa, Antonio; Davies, Gareth; Geist, Eric L.; Glimsdal, Sylfest; González, Frank I.; Griffin, Jonathan; Harbitz, Carl B.; LeVeque, Randall J.; Lorito, Stefano; Løvholt, Finn; Omira, Rachid; Mueller, Christof; Paris, Raphaël; Parsons, Thomas E.; Polet, Jascha; Power, William; Selva, Jacopo; Sørensen, Mathilde B.; Thio, Hong Kie

2017-01-01

Applying probabilistic methods to infrequent but devastating natural events is intrinsically challenging. For tsunami analyses, a suite of geophysical assessments should be in principle evaluated because of the different causes generating tsunamis (earthquakes, landslides, volcanic activity, meteorological events, and asteroid impacts) with varying mean recurrence rates. Probabilistic Tsunami Hazard Analyses (PTHAs) are conducted in different areas of the world at global, regional, and local scales with the aim of understanding tsunami hazard to inform tsunami risk reduction activities. PTHAs enhance knowledge of the potential tsunamigenic threat by estimating the probability of exceeding specific levels of tsunami intensity metrics (e.g., run-up or maximum inundation heights) within a certain period of time (exposure time) at given locations (target sites); these estimates can be summarized in hazard maps or hazard curves. This discussion presents a broad overview of PTHA, including (i) sources and mechanisms of tsunami generation, emphasizing the variety and complexity of the tsunami sources and their generation mechanisms, (ii) developments in modeling the propagation and impact of tsunami waves, and (iii) statistical procedures for tsunami hazard estimates that include the associated epistemic and aleatoric uncertainties. Key elements in understanding the potential tsunami hazard are discussed, in light of the rapid development of PTHA methods during the last decade and the globally distributed applications, including the importance of considering multiple sources, their relative intensities, probabilities of occurrence, and uncertainties in an integrated and consistent probabilistic framework.

Probabilistic Tsunami Hazard Analysis: Multiple Sources and Global Applications

NASA Astrophysics Data System (ADS)

Grezio, Anita; Babeyko, Andrey; Baptista, Maria Ana; Behrens, Jörn; Costa, Antonio; Davies, Gareth; Geist, Eric L.; Glimsdal, Sylfest; González, Frank I.; Griffin, Jonathan; Harbitz, Carl B.; LeVeque, Randall J.; Lorito, Stefano; Løvholt, Finn; Omira, Rachid; Mueller, Christof; Paris, Raphaël.; Parsons, Tom; Polet, Jascha; Power, William; Selva, Jacopo; Sørensen, Mathilde B.; Thio, Hong Kie

2017-12-01

Applying probabilistic methods to infrequent but devastating natural events is intrinsically challenging. For tsunami analyses, a suite of geophysical assessments should be in principle evaluated because of the different causes generating tsunamis (earthquakes, landslides, volcanic activity, meteorological events, and asteroid impacts) with varying mean recurrence rates. Probabilistic Tsunami Hazard Analyses (PTHAs) are conducted in different areas of the world at global, regional, and local scales with the aim of understanding tsunami hazard to inform tsunami risk reduction activities. PTHAs enhance knowledge of the potential tsunamigenic threat by estimating the probability of exceeding specific levels of tsunami intensity metrics (e.g., run-up or maximum inundation heights) within a certain period of time (exposure time) at given locations (target sites); these estimates can be summarized in hazard maps or hazard curves. This discussion presents a broad overview of PTHA, including (i) sources and mechanisms of tsunami generation, emphasizing the variety and complexity of the tsunami sources and their generation mechanisms, (ii) developments in modeling the propagation and impact of tsunami waves, and (iii) statistical procedures for tsunami hazard estimates that include the associated epistemic and aleatoric uncertainties. Key elements in understanding the potential tsunami hazard are discussed, in light of the rapid development of PTHA methods during the last decade and the globally distributed applications, including the importance of considering multiple sources, their relative intensities, probabilities of occurrence, and uncertainties in an integrated and consistent probabilistic framework.

Probabilistic analysis of tsunami hazards

USGS Publications Warehouse

Geist, E.L.; Parsons, T.

2006-01-01

Determining the likelihood of a disaster is a key component of any comprehensive hazard assessment. This is particularly true for tsunamis, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models. We discuss probabilistic tsunami hazard analysis (PTHA) from the standpoint of integrating computational methods with empirical analysis of past tsunami runup. PTHA is derived from probabilistic seismic hazard analysis (PSHA), with the main difference being that PTHA must account for far-field sources. The computational methods rely on numerical tsunami propagation models rather than empirical attenuation relationships as in PSHA in determining ground motions. Because a number of source parameters affect local tsunami runup height, PTHA can become complex and computationally intensive. Empirical analysis can function in one of two ways, depending on the length and completeness of the tsunami catalog. For site-specific studies where there is sufficient tsunami runup data available, hazard curves can primarily be derived from empirical analysis, with computational methods used to highlight deficiencies in the tsunami catalog. For region-wide analyses and sites where there are little to no tsunami data, a computationally based method such as Monte Carlo simulation is the primary method to establish tsunami hazards. Two case studies that describe how computational and empirical methods can be integrated are presented for Acapulco, Mexico (site-specific) and the U.S. Pacific Northwest coastline (region-wide analysis).

Educating and Preparing for Tsunamis in the Caribbean

NASA Astrophysics Data System (ADS)

von Hillebrandt-Andrade, C.; Aliaga, B.; Edwards, S.

2013-12-01

The Caribbean and Adjacent Regions has a long history of tsunamis and earthquakes. Over the past 500 years, more than 75 tsunamis have been documented in the region by the NOAA National Geophysical Data Center. Just since 1842, 3446 lives have been lost to tsunamis; this is more than in the Northeastern Pacific for the same time period. With a population of almost 160 million, over 40 million visitors a year and a heavy concentration of residents, tourists, businesses and critical infrastructure along its shores (especially in the northern and eastern Caribbean), the risk to lives and livelihoods is greater than ever before. The only way to survive a tsunami is to get out of harm's way before the waves strike. In the Caribbean given the relatively short distances from faults, potential submarine landslides and volcanoes to some of the coastlines, the tsunamis are likely to be short fused, so it is imperative that tsunami warnings be issued extremely quickly and people be educated on how to recognize and respond. Nevertheless, given that tsunamis occur infrequently as compared with hurricanes, it is a challenge for them to receive the priority they require in order to save lives when the next one strikes the region. Close cooperation among countries and territories is required for warning, but also for education and public awareness. Geographical vicinity and spoken languages need to be factored in when developing tsunami preparedness in the Caribbean, to make sure citizens receive a clear, reliable and sound science based message about the hazard and the risk. In 2006, in the wake of the Indian Ocean tsunami and after advocating without success for a Caribbean Tsunami Warning System since the mid 90's, the Intergovernmental Oceanographic Commission of UNESCO established the Intergovernmental Coordination Group for the Tsunami and other Coastal Hazards Warning System for the Caribbean and Adjacent Regions (CARIBE EWS). Its purpose is to advance an end to end tsunami warning system that serves regionally and delivers locally, saving lives and livelihoods, not only from tsunamis, but all coastal hazards. Through this and other platforms, physical and social scientists, emergency managers and elected officials have been working together via different mechanisms. Community based recognition programs, like the TsunamiReadyTM Program, regional tsunami exercises, sub-regional public education activities such as the Tsunami Smart campaigns, internet technologies, social media, meetings and conferences, identification of local and national champions, capitalization of news breaking tsunamis and earthquakes, economic resources for equipment and training have all been key to developing a tsunami safer Caribbean. Given these efforts, according to a 2013 survey, 93% of the countries covered by CARIBE EWS have tsunami response protocols in place, although much more work is required. In 2010 the US National Weather Service established the Caribbean Tsunami Warning Program as the first step towards a Caribbean Tsunami Warning Center in the region. In 2013 the Caribbean Tsunami Information Center was established in Barbados. Both these institutions which serve the region play a key role for promoting both the warning and educational components of the warning system.

Impact of Near-Field, Deep-Ocean Tsunami Observations on Forecasting the 7 December 2012 Japanese Tsunami

NASA Astrophysics Data System (ADS)

Bernard, Eddie; Wei, Yong; Tang, Liujuan; Titov, Vasily

2014-12-01

Following the devastating 11 March 2011 tsunami, two deep-ocean assessment and reporting of tsunamis (DART®)(DART® and the DART® logo are registered trademarks of the National Oceanic and Atmospheric Administration, used with permission) stations were deployed in Japanese waters by the Japanese Meteorological Agency. Two weeks after deployment, on 7 December 2012, a M w 7.3 earthquake off Japan's Pacific coastline generated a tsunami. The tsunami was recorded at the two Japanese DARTs as early as 11 min after the earthquake origin time, which set a record as the fastest tsunami detecting time at a DART station. These data, along with those recorded at other DARTs, were used to derive a tsunami source using the National Oceanic and Atmospheric Administration tsunami forecast system. The results of our analysis show that data provided by the two near-field Japanese DARTs can not only improve the forecast speed but also the forecast accuracy at the Japanese tide gauge stations. This study provides important guidelines for early detection and forecasting of local tsunamis.

Source processes for the probabilistic assessment of tsunami hazards

USGS Publications Warehouse

Geist, Eric L.; Lynett, Patrick J.

2014-01-01

The importance of tsunami hazard assessment has increased in recent years as a result of catastrophic consequences from events such as the 2004 Indian Ocean and 2011 Japan tsunamis. In particular, probabilistic tsunami hazard assessment (PTHA) methods have been emphasized to include all possible ways a tsunami could be generated. Owing to the scarcity of tsunami observations, a computational approach is used to define the hazard. This approach includes all relevant sources that may cause a tsunami to impact a site and all quantifiable uncertainty. Although only earthquakes were initially considered for PTHA, recent efforts have also attempted to include landslide tsunami sources. Including these sources into PTHA is considerably more difficult because of a general lack of information on relating landslide area and volume to mean return period. The large variety of failure types and rheologies associated with submarine landslides translates to considerable uncertainty in determining the efficiency of tsunami generation. Resolution of these and several other outstanding problems are described that will further advance PTHA methodologies leading to a more accurate understanding of tsunami hazard.

Modeling influence of tide stages on forecasts of the 2010 Chilean tsunami

NASA Astrophysics Data System (ADS)

Uslu, B. U.; Chamberlin, C.; Walsh, D.; Eble, M. C.

2010-12-01

The impact of the 2010 Chilean tsunami is studied using the NOAA high-resolution tsunami forecast model augmented to include modeled tide heights in addition to deep-water tsunami propagation as boundary-condition input. The Chilean tsunami was observed at the Los Angeles tide station at mean low water, Hilo at low, Pago Pago at mid tide and Wake Island near high tide. Because the tsunami arrived at coastal communities at a representative variety of tide stages, 2010 Chile tsunami provides opportunity to study the tsunami impacts at different tide levels to different communities. The current forecast models are computed with a constant tidal stage, and this study evaluates techniques for adding an additional varying predicted tidal component in a forecasting context. Computed wave amplitudes, wave currents and flooding are compared at locations around the Pacific, and the difference in tsunami impact due to tidal stage is studied. This study focuses on how tsunami impacts vary with different tide levels, and helps us understand how the inclusion of tidal components can improve real-time forecast accuracy.

The Great Chilean Tsunamis of 2010, 2014 and 2015 on the Coast and Offshore of Mexico: Comparative Features Based on Open-Ocean Energy Parameterization

NASA Astrophysics Data System (ADS)

Rabinovich, A.; Zaytsev, O.; Thomson, R.

2016-12-01

The three recent great earthquakes offshore of Chile on 27 February 2010 (Maule, Mw 8.8), 1 April 2014 (Iquique, Mw 8.2) and 16 September 2015 (Illapel, Mw 8.3) generated major trans-oceanic tsunamis that spread throughout the entire Pacific Ocean and were measured by numerous coastal tide gauges and open-ocean DART stations. Statistical and spectral analyses of the tsunami waves from the three events recorded on the Pacific coast of Mexico enabled us to compare the events and to identify coastal "hot spots", regions with maximum tsunami risk. Based on joint spectral analyses of tsunamis and background noise, we have developed a method for reconstructing the "true" tsunami spectra in the deep ocean. The "reconstructed" open-ocean tsunami spectra are in excellent agreement with the actual tsunami spectra evaluated from direct analysis of the DART records offshore of Mexico. We have further used the spectral estimates to parameterize the energy of the three Chilean tsunamis based on the total open-ocean tsunami energy and frequency content of the individual events.

U.S. Tsunami Warning System: Advancements since the 2004 Indian Ocean Tsunami (Invited)

NASA Astrophysics Data System (ADS)

Whitmore, P.

2009-12-01

The U.S. government embarked on a strengthening program for the U.S. Tsunami Warning System (TWS) in the aftermath of the disastrous 2004 Indian Ocean tsunami. The program was designed to improve several facets of the U.S. TWS, including: upgrade of the coastal sea level network - 16 new stations plus higher transmission rates; expansion of the deep ocean tsunameter network - 7 sites increased to 39; upgrade of seismic networks - both USGS and Tsunami Warning Center (TWC); increase of TWC staff to allow 24x7 coverage at two centers; development of an improved tsunami forecast system; increased preparedness in coastal communities; expansion of the Pacific Tsunami Warning Center facility; and improvement of the tsunami data archive effort at the National Geophysical Data Center. The strengthening program has been completed and has contributed to the many improvements attained in the U.S. TWS since 2004. Some of the more significant enhancements to the program are: the number of sea level and seismic sites worldwide available to the TWCs has more than doubled; the TWC areas-of-responsibility expanded to include the U.S./Canadian Atlantic coasts, Indian Ocean, Caribbean Sea, Gulf of Mexico, and U.S. Arctic coast; event response time decreased by approximately one-half; product accuracy has improved; a tsunami forecast system developed by NOAA capable of forecasting inundation during an event has been delivered to the TWCs; warning areas are now defined by pre-computed or forecasted threat versus distance or travel time, significantly reducing the amount of coast put in a warning; new warning dissemination techniques have been implemented to reach a broader audience in less time; tsunami product content better reflects the expected impact level; the number of TsunamiReady communities has quadrupled; and the historical data archive has increased in quantity and accuracy. In addition to the strengthening program, the U.S. National Tsunami Hazard Mitigation Program (NTHMP) has expanded its efforts since 2004 and improved tsunami preparedness throughout U.S. coastal communities. The NTHMP is a partnership of federal agencies and state tsunami response agencies whose efforts include: development of inundation and evacuation maps for most highly threatened communities; tsunami evacuation and educational signage for coastal communities; support for tsunami educational, awareness and planning seminars; increased number of local tsunami warning dissemination devices such as sirens; and support for regional tsunami exercises. These activities are major factors that have contributed to the increase of TsunamiReady communities throughout the country.

Tsunami response system for ports in Korea

NASA Astrophysics Data System (ADS)

Cho, H.-R.; Cho, J.-S.; Cho, Y.-S.

2015-09-01

The tsunamis that have occurred in many places around the world over the past decade have taken a heavy toll on human lives and property. The eastern coast of the Korean Peninsula is not safe from tsunamis, particularly the eastern coastal areas, which have long sustained tsunami damage. The eastern coast had been attacked by 1983 and 1993 tsunami events. The aim of this study was to mitigate the casualties and property damage against unexpected tsunami attacks along the eastern coast of the Korean Peninsula by developing a proper tsunami response system for important ports and harbors with high population densities and high concentrations of key national industries. The system is made based on numerical and physical modelings of 3 historical and 11 virtual tsunamis events, field surveys, and extensive interviews with related people.

Rapid Tsunami Inundation Forecast from Near-field or Far-field Earthquakes using Pre-computed Tsunami Database: Pelabuhan Ratu, Indonesia

NASA Astrophysics Data System (ADS)

Gusman, A. R.; Setiyono, U.; Satake, K.; Fujii, Y.

2017-12-01

We built pre-computed tsunami inundation database in Pelabuhan Ratu, one of tsunami-prone areas on the southern coast of Java, Indonesia. The tsunami database can be employed for a rapid estimation of tsunami inundation during an event. The pre-computed tsunami waveforms and inundations are from a total of 340 scenarios ranging from 7.5 to 9.2 in moment magnitude scale (Mw), including simple fault models of 208 thrust faults and 44 tsunami earthquakes on the plate interface, as well as 44 normal faults and 44 reverse faults in the outer-rise region. Using our tsunami inundation forecasting algorithm (NearTIF), we could rapidly estimate the tsunami inundation in Pelabuhan Ratu for three different hypothetical earthquakes. The first hypothetical earthquake is a megathrust earthquake type (Mw 9.0) offshore Sumatra which is about 600 km from Pelabuhan Ratu to represent a worst-case event in the far-field. The second hypothetical earthquake (Mw 8.5) is based on a slip deficit rate estimation from geodetic measurements and represents a most likely large event near Pelabuhan Ratu. The third hypothetical earthquake is a tsunami earthquake type (Mw 8.1) which often occur south off Java. We compared the tsunami inundation maps produced by the NearTIF algorithm with results of direct forward inundation modeling for the hypothetical earthquakes. The tsunami inundation maps produced from both methods are similar for the three cases. However, the tsunami inundation map from the inundation database can be obtained in much shorter time (1 min) than the one from a forward inundation modeling (40 min). These indicate that the NearTIF algorithm based on pre-computed inundation database is reliable and useful for tsunami warning purposes. This study also demonstrates that the NearTIF algorithm can work well even though the earthquake source is located outside the area of fault model database because it uses a time shifting procedure for the best-fit scenario searching.

Real-time correction of tsunami site effect by frequency-dependent tsunami-amplification factor

NASA Astrophysics Data System (ADS)

Tsushima, H.

2017-12-01

For tsunami early warning, I developed frequency-dependent tsunami-amplification factor and used it to design a recursive digital filter that can be applicable for real-time correction of tsunami site response. In this study, I assumed that a tsunami waveform at an observing point could be modeled by convolution of source, path and site effects in time domain. Under this assumption, spectral ratio between offshore and the nearby coast can be regarded as site response (i.e. frequency-dependent amplification factor). If the amplification factor can be prepared before tsunamigenic earthquakes, its temporal convolution to offshore tsunami waveform provides tsunami prediction at coast in real time. In this study, tsunami waveforms calculated by tsunami numerical simulations were used to develop frequency-dependent tsunami-amplification factor. Firstly, I performed numerical tsunami simulations based on nonlinear shallow-water theory from many tsuanmigenic earthquake scenarios by varying the seismic magnitudes and locations. The resultant tsunami waveforms at offshore and the nearby coastal observing points were then used in spectral-ratio analysis. An average of the resulted spectral ratios from the tsunamigenic-earthquake scenarios is regarded as frequency-dependent amplification factor. Finally, the estimated amplification factor is used in design of a recursive digital filter that can be applicable in time domain. The above procedure is applied to Miyako bay at the Pacific coast of northeastern Japan. The averaged tsunami-height spectral ratio (i.e. amplification factor) between the location at the center of the bay and the outside show a peak at wave-period of 20 min. A recursive digital filter based on the estimated amplification factor shows good performance in real-time correction of tsunami-height amplification due to the site effect. This study is supported by Japan Society for the Promotion of Science (JSPS) KAKENHI grant 15K16309.

A Collaborative Effort Between Caribbean States for Tsunami Numerical Modeling: Case Study CaribeWave15

NASA Astrophysics Data System (ADS)

Chacón-Barrantes, Silvia; López-Venegas, Alberto; Sánchez-Escobar, Rónald; Luque-Vergara, Néstor

2018-04-01

Historical records have shown that tsunami have affected the Caribbean region in the past. However infrequent, recent studies have demonstrated that they pose a latent hazard for countries within this basin. The Hazard Assessment Working Group of the ICG/CARIBE-EWS (Intergovernmental Coordination Group of the Early Warning System for Tsunamis and Other Coastal Threats for the Caribbean Sea and Adjacent Regions) of IOC/UNESCO has a modeling subgroup, which seeks to develop a modeling platform to assess the effects of possible tsunami sources within the basin. The CaribeWave tsunami exercise is carried out annually in the Caribbean region to increase awareness and test tsunami preparedness of countries within the basin. In this study we present results of tsunami inundation using the CaribeWave15 exercise scenario for four selected locations within the Caribbean basin (Colombia, Costa Rica, Panamá and Puerto Rico), performed by tsunami modeling researchers from those selected countries. The purpose of this study was to provide the states with additional results for the exercise. The results obtained here were compared to co-seismic deformation and tsunami heights within the basin (energy plots) provided for the exercise to assess the performance of the decision support tools distributed by PTWC (Pacific Tsunami Warning Center), the tsunami service provider for the Caribbean basin. However, comparison of coastal tsunami heights was not possible, due to inconsistencies between the provided fault parameters and the modeling results within the provided exercise products. Still, the modeling performed here allowed to analyze tsunami characteristics at the mentioned states from sources within the North Panamá Deformed Belt. The occurrence of a tsunami in the Caribbean may affect several countries because a great variety of them share coastal zones in this basin. Therefore, collaborative efforts similar to the one presented in this study, particularly between neighboring countries, are critical to assess tsunami hazard and increase preparedness within the countries.

Challenges in Defining Tsunami Wave Height

NASA Astrophysics Data System (ADS)

Stroker, K. J.; Dunbar, P. K.; Mungov, G.; Sweeney, A.; Arcos, N. P.

2017-12-01

The NOAA National Centers for Environmental Information (NCEI) and co-located World Data Service for Geophysics maintain the global tsunami archive consisting of the historical tsunami database, imagery, and raw and processed water level data. The historical tsunami database incorporates, where available, maximum wave heights for each coastal tide gauge and deep-ocean buoy that recorded a tsunami signal. These data are important because they are used for tsunami hazard assessment, model calibration, validation, and forecast and warning. There have been ongoing discussions in the tsunami community about the correct way to measure and report these wave heights. It is important to understand how these measurements might vary depending on how the data were processed and the definition of maximum wave height. On September 16, 2015, an 8.3 Mw earthquake located 48 km west of Illapel, Chile generated a tsunami that was observed all over the Pacific region. We processed the time-series water level data for 57 tide gauges that recorded this tsunami and compared the maximum wave heights determined from different definitions. We also compared the maximum wave heights from the NCEI-processed data with the heights reported by the NOAA Tsunami Warning Centers. We found that in the near field different methods of determining the maximum tsunami wave heights could result in large differences due to possible instrumental clipping. We also found that the maximum peak is usually larger than the maximum amplitude (½ peak-to-trough), but the differences for the majority of the stations were <20 cm. For this event, the maximum tsunami wave heights determined by either definition (maximum peak or amplitude) would have validated the forecasts issued by the NOAA Tsunami Warning Centers. Since there is currently only one field in the NCEI historical tsunami database to store the maximum tsunami wave height, NCEI will consider adding an additional field for the maximum peak measurement.

New Activities of the U.S. National Tsunami Hazard Mitigation Program, Mapping and Modeling Subcommittee

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Eble, M. C.

2013-12-01

The U.S. National Tsunami Hazard Mitigation Program (NTHMP) is comprised of representatives from coastal states and federal agencies who, under the guidance of NOAA, work together to develop protocols and products to help communities prepare for and mitigate tsunami hazards. Within the NTHMP are several subcommittees responsible for complimentary aspects of tsunami assessment, mitigation, education, warning, and response. The Mapping and Modeling Subcommittee (MMS) is comprised of state and federal scientists who specialize in tsunami source characterization, numerical tsunami modeling, inundation map production, and warning forecasting. Until September 2012, much of the work of the MMS was authorized through the Tsunami Warning and Education Act, an Act that has since expired but the spirit of which is being adhered to in parallel with reauthorization efforts. Over the past several years, the MMS has developed guidance and best practices for states and territories to produce accurate and consistent tsunami inundation maps for community level evacuation planning, and has conducted benchmarking of numerical inundation models. Recent tsunami events have highlighted the need for other types of tsunami hazard analyses and products for improving evacuation planning, vertical evacuation, maritime planning, land-use planning, building construction, and warning forecasts. As the program responsible for producing accurate and consistent tsunami products nationally, the NTHMP-MMS is initiating a multi-year plan to accomplish the following: 1) Create and build on existing demonstration projects that explore new tsunami hazard analysis techniques and products, such as maps identifying areas of strong currents and potential damage within harbors as well as probabilistic tsunami hazard analysis for land-use planning. 2) Develop benchmarks for validating new numerical modeling techniques related to current velocities and landslide sources. 3) Generate guidance and protocols for the production and use of new tsunami hazard analysis products. 4) Identify multistate collaborations and funding partners interested in these new products. Application of these new products will improve the overall safety and resilience of coastal communities exposed to tsunami hazards.

A Collaborative Effort Between Caribbean States for Tsunami Numerical Modeling: Case Study CaribeWave15

NASA Astrophysics Data System (ADS)

Chacón-Barrantes, Silvia; López-Venegas, Alberto; Sánchez-Escobar, Rónald; Luque-Vergara, Néstor

2017-10-01

Historical records have shown that tsunami have affected the Caribbean region in the past. However infrequent, recent studies have demonstrated that they pose a latent hazard for countries within this basin. The Hazard Assessment Working Group of the ICG/CARIBE-EWS (Intergovernmental Coordination Group of the Early Warning System for Tsunamis and Other Coastal Threats for the Caribbean Sea and Adjacent Regions) of IOC/UNESCO has a modeling subgroup, which seeks to develop a modeling platform to assess the effects of possible tsunami sources within the basin. The CaribeWave tsunami exercise is carried out annually in the Caribbean region to increase awareness and test tsunami preparedness of countries within the basin. In this study we present results of tsunami inundation using the CaribeWave15 exercise scenario for four selected locations within the Caribbean basin (Colombia, Costa Rica, Panamá and Puerto Rico), performed by tsunami modeling researchers from those selected countries. The purpose of this study was to provide the states with additional results for the exercise. The results obtained here were compared to co-seismic deformation and tsunami heights within the basin (energy plots) provided for the exercise to assess the performance of the decision support tools distributed by PTWC (Pacific Tsunami Warning Center), the tsunami service provider for the Caribbean basin. However, comparison of coastal tsunami heights was not possible, due to inconsistencies between the provided fault parameters and the modeling results within the provided exercise products. Still, the modeling performed here allowed to analyze tsunami characteristics at the mentioned states from sources within the North Panamá Deformed Belt. The occurrence of a tsunami in the Caribbean may affect several countries because a great variety of them share coastal zones in this basin. Therefore, collaborative efforts similar to the one presented in this study, particularly between neighboring countries, are critical to assess tsunami hazard and increase preparedness within the countries.

Challenges in Defining Tsunami Wave Heights

NASA Astrophysics Data System (ADS)

Dunbar, Paula; Mungov, George; Sweeney, Aaron; Stroker, Kelly; Arcos, Nicolas

2017-08-01

The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) and co-located World Data Service for Geophysics maintain the global tsunami archive consisting of the historical tsunami database, imagery, and raw and processed water level data. The historical tsunami database incorporates, where available, maximum wave heights for each coastal tide gauge and deep-ocean buoy that recorded a tsunami signal. These data are important because they are used for tsunami hazard assessment, model calibration, validation, and forecast and warning. There have been ongoing discussions in the tsunami community about the correct way to measure and report these wave heights. It is important to understand how these measurements might vary depending on how the data were processed and the definition of maximum wave height. On September 16, 2015, an 8.3 M w earthquake located 48 km west of Illapel, Chile generated a tsunami that was observed all over the Pacific region. We processed the time-series water level data for 57 coastal tide gauges that recorded this tsunami and compared the maximum wave heights determined from different definitions. We also compared the maximum wave heights from the NCEI-processed data with the heights reported by the NOAA Tsunami Warning Centers. We found that in the near field different methods of determining the maximum tsunami wave heights could result in large differences due to possible instrumental clipping. We also found that the maximum peak is usually larger than the maximum amplitude (½ peak-to-trough), but the differences for the majority of the stations were <20 cm. For this event, the maximum tsunami wave heights determined by either definition (maximum peak or amplitude) would have validated the forecasts issued by the NOAA Tsunami Warning Centers. Since there is currently only one field in the NCEI historical tsunami database to store the maximum tsunami wave height for each tide gauge and deep-ocean buoy, NCEI will consider adding an additional field for the maximum peak measurement.

Effects of Harbor Modification on Crescent City, California's Tsunami Vulnerability

NASA Astrophysics Data System (ADS)

Dengler, Lori; Uslu, Burak

2011-06-01

More damaging tsunamis have impacted Crescent City, California in historic times than any other location on the West Coast of the USA. Crescent City's harbor has undergone significant modification since the early 20th century, including construction of several breakwaters, dredging, and a 200 × 300 m2 small boat basin. In 2006, a M w 8.3 earthquake in the Kuril Islands generated a moderate Pacific-wide tsunami. Crescent City recorded the highest amplitudes of any tide gauge in the Pacific and was the only location to experience structural damage. Strong currents damaged docks and boats within the small boat basin, causing more than US 20 million in damage and replacement costs. We examine how modifications to Crescent City's harbor may have affected its vulnerability to moderate tsunamis such as the 2006 event. A bathymetric grid of the basin was constructed based on US Army Corps of Engineers soundings in 1964 and 1965 before the construction of the small boat basin. The method of splitting tsunamis was used to estimate tsunami water heights and current velocities at several locations in the harbor using both the 1964-1965 grid and the 2006 bathymetric grid for the 2006 Kuril event and a similar-sized source along the Sanriku coast of Japan. Model velocity outputs are compared for the two different bathymetries at the tide gauge location and at six additional computational sites in the harbor. The largest difference between the two grids is at the small boat basin entrance, where the 2006 bathymetry produces currents over three times the strength of the currents produced by the 1965 bathymetry. Peak currents from a Sanriku event are comparable to those produced by the 2006 event, and within the boat basin may have been higher. The modifications of the harbor, and in particular the addition of the small boat basin, appear to have contributed to the high current velocities and resulting damage in 2006 and help to explain why the 1933 M w 8.4-8.7 Sanriku tsunami caused no damage at Crescent City.

Impact of Solar Array Position on ISS Vehicle Charging

NASA Technical Reports Server (NTRS)

Alred, John; Mikatarian, Ronald; Koontz, Steve

2006-01-01

The International Space Station (ISS), because of its large structure and high voltage solar arrays, has a complex plasma interaction with the ionosphere in low Earth orbit (LEO). This interaction of the ISS US Segment photovoltaic (PV) power system with the LEO ionospheric plasma produces floating potentials on conducting elements of the ISS structure relative to the local plasma environment. To control the ISS floating potentials, two Plasma Contactor Units (PCUs) are installed on the Z1 truss. Each PCU discharges accumulated electrons from the Space Station structure, thus reducing the potential difference between the ISS structure and the surrounding charged plasma environment. Operations of the PCUs were intended to keep the ISS floating potential to 40 Volts (Reference 1). Exposed dielectric surfaces overlying conducting structure on the Space Station will collect an opposite charge from the ionosphere as the ISS charges. In theory, when an Extravehicular Activity (EVA) crewmember is tethered to structure via the crew safety tether or when metallic surfaces of the Extravehicular Mobility Unit (EMU) come in contact with conducting metallic surfaces of the ISS, the EMU conducting components, including the perspiration-soaked crewmember inside, can become charged to the Space Station floating potential. The concern is the potential dielectric breakdown of anodized aluminum surfaces on the EMU producing an arc from the EMU to the ambient plasma, or nearby ISS structure. If the EMU arcs, an electrical current of an unknown magnitude and duration may conduct through the EVA crewmember, producing an unacceptable condition. This electrical current may be sufficient to startle or fatally shock the EVA crewmember (Reference 2). Hence, as currently defined by the EVA community, the ISS floating potential for all nominal and contingency EVA worksites and translation paths must have a magnitude less than 40 volts relative to the local ionosphere at all times during EVA. Arcing from the EMU is classified as a catastrophic hazard, which requires two-failure tolerant controls, i.e., three hazard controls. Each PCU is capable of maintaining the ISS floating potential below the requirement during EVA. The two PCUs provide a single failure tolerant control of ISS floating potential. In the event of the failure of one or two PCUs, a combination of solar array shunting and turning the solar arrays into their own wakes will be used to supply control of the plasma hazard (Reference 3). The purpose of this paper is to present on-orbit information that shows that ISS solar array placement with respect to the ISS velocity vector can control solar array plasma charging, and hence, provide an operational control for the plasma hazard. Also, this paper will present on-orbit information that shows that shunting of the ISS solar arrays can control solar array plasma charging, and hence, provide an additional operational control for the plasma hazard.

Tsunami mitigation and preparedness activities in California: Chapter L in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

USGS Publications Warehouse

Wilson, Rick; Miller, Kevin H.

2013-01-01

scenario-specific, tsunami evacuation “playbook” maps and guidance in-harbor hazard maps and offshore safety zones for potential boat evacuation during future distant source events; “probability-based” products for land-use planning under the California Seismic Hazard Mapping Act; and an expansion of real-time and post-tsunami field reconnaissance teams and information sharing through a state-wide clearinghouse. The state tsunami program has benefitted greatly from participation in the SAFRR tsunami scenario process, and hopes to continue this relationship with the U.S. Geological Survey to help improve tsunami preparedness in California.

Modeling the 2004Indian Ocean Tsunami for Introductory Physics Students

NASA Astrophysics Data System (ADS)

DiLisi, Gregory A.; Rarick, Richard A.

2006-12-01

In this paper we develop materials to address student interest in the Indian Ocean tsunami of December 2004. We discuss the physical characteristics of tsunamis and some of the specific data regarding the 2004 event. Finally, we create an easy-to-make tsunami tank to run simulations in the classroom. The simulations exhibit three dramatic signatures of tsunamis, namely, as a tsunami moves into shallow water its amplitude increases, its wavelength and speed decrease, and its leading edge becomes increasingly steep as if to "break" or "crash." Using our tsunami tank, these realistic features were easy to observe in the classroom and evoked an enthusiastic response from our students.

Mega Tsunamis of the World Ocean and Their Implication for the Tsunami Hazard Assessment

NASA Astrophysics Data System (ADS)

Gusiakov, V. K.

2014-12-01

Mega tsunamis are the strongest tsunamigenic events of tectonic origin that are characterized by run-up heights up to 40-50 m measured along a considerable part of the coastline (up to 1000 km). One of the most important features of mega-tsunamis is their ability to cross the entire oceanic basin and to cause an essential damage to its opposite coast. Another important feature is their ability to penetrate into the marginal seas (like the Sea of Okhotsk, the Bering Sea) and cause dangerous water level oscillations along the parts of the coast, which are largely protected by island arcs against the impact of the strongest regional tsunamis. Among all known historical tsunamis (nearly 2250 events during the last 4000 years) they represent only a small fraction (less than 1%) however they are responsible for more than half the total tsunami fatalities and a considerable part of the overall tsunami damage. The source of all known mega tsunamis is subduction submarine earthquakes with magnitude 9.0 or higher having a return period from 200-300 years to 1000-1200 years. The paper presents a list of 15 mega tsunami events identified so far in historical catalogs with their basic source parameters, near-field and far-field impact effects and their generation and propagation features. The far-field impact of mega tsunamis is largely controlled by location and orientation of their earthquake source as well as by deep ocean bathymetry features. We also discuss the problem of the long-term tsunami hazard assessment when the occurrence of mega tsunamis is taken into account.

Development of performance specifications for hybrid modeling of floating wind turbines in wave basin tests

DOE PAGES

Hall, Matthew; Goupee, Andrew; Jonkman, Jason

2017-08-24

Hybrid modeling—combining physical testing and numerical simulation in real time$-$opens new opportunities in floating wind turbine research. Wave basin testing is an important validation step for floating support structure design, but the conventional approaches that use physical wind above the basin are limited by scaling problems in the aerodynamics. Applying wind turbine loads with an actuation system that is controlled by a simulation responding to the basin test in real time offers a way to avoid scaling problems and reduce cost barriers for floating wind turbine design validation in realistic coupled wind and wave conditions. This paper demonstrates the developmentmore » of performance specifications for a system that couples a wave basin experiment with a wind turbine simulation. Two different points for the hybrid coupling are considered: the tower-base interface and the aero-rotor interface (the boundary between aerodynamics and the rotor structure). Analyzing simulations of three floating wind turbine designs across seven load cases reveals the motion and force requirements of the coupling system. By simulating errors in the hybrid coupling system, the sensitivity of the floating wind turbine response to coupling quality can be quantified. The sensitivity results can then be used to determine tolerances for motion tracking errors, force actuation errors, bandwidth limitations, and latency in the hybrid coupling system. These tolerances can guide the design of hybrid coupling systems to achieve desired levels of accuracy. An example demonstrates how the developed methods can be used to generate performance specifications for a system at 1:50 scale. Results show that sensitivities vary significantly between support structure designs and that coupling at the aero-rotor interface has less stringent requirements than those for coupling at the tower base. As a result, the methods and results presented here can inform design of future hybrid coupling systems and enhance understanding of how test results are affected by hybrid coupling quality.« less

Development of performance specifications for hybrid modeling of floating wind turbines in wave basin tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, Matthew; Goupee, Andrew; Jonkman, Jason

Hybrid modeling—combining physical testing and numerical simulation in real time$-$opens new opportunities in floating wind turbine research. Wave basin testing is an important validation step for floating support structure design, but the conventional approaches that use physical wind above the basin are limited by scaling problems in the aerodynamics. Applying wind turbine loads with an actuation system that is controlled by a simulation responding to the basin test in real time offers a way to avoid scaling problems and reduce cost barriers for floating wind turbine design validation in realistic coupled wind and wave conditions. This paper demonstrates the developmentmore » of performance specifications for a system that couples a wave basin experiment with a wind turbine simulation. Two different points for the hybrid coupling are considered: the tower-base interface and the aero-rotor interface (the boundary between aerodynamics and the rotor structure). Analyzing simulations of three floating wind turbine designs across seven load cases reveals the motion and force requirements of the coupling system. By simulating errors in the hybrid coupling system, the sensitivity of the floating wind turbine response to coupling quality can be quantified. The sensitivity results can then be used to determine tolerances for motion tracking errors, force actuation errors, bandwidth limitations, and latency in the hybrid coupling system. These tolerances can guide the design of hybrid coupling systems to achieve desired levels of accuracy. An example demonstrates how the developed methods can be used to generate performance specifications for a system at 1:50 scale. Results show that sensitivities vary significantly between support structure designs and that coupling at the aero-rotor interface has less stringent requirements than those for coupling at the tower base. As a result, the methods and results presented here can inform design of future hybrid coupling systems and enhance understanding of how test results are affected by hybrid coupling quality.« less

Performance Benchmarking of tsunami-HySEA for NTHMP Inundation Mapping Activities

NASA Astrophysics Data System (ADS)

González Vida, Jose M.; Castro, Manuel J.; Ortega Acosta, Sergio; Macías, Jorge; Millán, Alejandro

2016-04-01

According to the 2006 USA Tsunami Warning and Education Act, the tsunami inundation models used in the National Tsunami Hazard Mitigation Program (NTHMP) projects must be validated against some existing standard problems (see [OAR-PMEL-135], [Proceedings of the 2011 NTHMP Model Benchmarking Workshop]). These Benchmark Problems (BPs) cover different tsunami processes related to the inundation stage that the models must meet to achieve the NTHMP Mapping and Modeling Subcommittee (MMS) approval. Tsunami-HySEA solves the two-dimensional shallow-water system using a high-order path-conservative finite volume method. Values of h, qx and qy in each grid cell represent cell averages of the water depth and momentum components. The numerical scheme is conservative for both mass and momentum in flat bathymetries, and, in general, is mass preserving for arbitrary bathymetries. Tsunami-HySEA implements a PVM-type method that uses the fastest and the slowest wave speeds, similar to HLL method (see [Castro et al, 2012]). A general overview of the derivation of the high order methods is performed in [Castro et al, 2009]. For very big domains, Tsunami-HySEA also implements a two-step scheme similar to leap-frog for the propagation step and a second-order TVD-WAF flux-limiter scheme described in [de la Asunción et al, 2013] for the inundation step. Here, we present the results obtained by the model tsunami-HySEA against the proposed BPs. BP1: Solitary wave on a simple beach (non-breaking - analytic experiment). BP4: Solitary wave on a simple beach (breaking - laboratory experiment). BP6: Solitary wave on a conical island (laboratory experiment). BP7 - Runup on Monai Valley beach (laboratory experiment) and BP9: Okushiri Island tsunami (field experiment). The analysis and results of Tsunami-HySEA model are presented, concluding that the model meets the required objectives for all the BP proposed. References - Castro M.J., E.D. Fernández, A.M. Ferreiro, A. García, C. Parés (2009). High order extension of Roe schemes for two dimensional nonconservative hyperbolic systems. J. Sci. Comput. 39(1), 67-114. - Castro M.J., E.D. Fernández-Nieto (2012). A class of computationally fast first order finite volume solvers: PVM methods. SIAM J. Sci. Comput. 34, A2173-2196. - de la Asunción M., M.J. Castro, E.D. Fernández-Nieto, J.M. Mantas, et al. Efficient GPU implementation of a two waves TVD-WAF method for the two-dimensional one layer shallow water system on structured meshes (2013). Computers & Fluids 80, 441-452. - OAR PMEL-135. Synolakis, C.E., E.N. Bernard, V.V. Titov, U. Kânoǧlu, and F.I. González (2007). Standards, criteria, and procedures for NOAA evaluation of tsunami numerical models. NOAA Tech. Memo. NOAA/Pacific Marine Environmental Laboratory, Seattle, WA, 55 pp. - Proceedings and results of the 2011 NTHMP Model Benchmarking Workshop. NOAA Special Report. July 2012. Acknowledgements This research has been partially supported by the Junta de Andalucía research project TESELA (P11-RNM7069), the Spanish Government Research project DAIFLUID (MTM2012-38383-C02-01) and the Unit of Numerical Methods (UNM) of the Research Support Central Services (SCAI) of the University of Málaga.

A Walk through TRIDEC's intermediate Tsunami Early Warning System for the Turkish and Portuguese NEAMWave12 exercise tsunami scenarios

NASA Astrophysics Data System (ADS)

Hammitzsch, Martin; Lendholt, Matthias; Reißland, Sven; Schulz, Jana

2013-04-01

On November 27-28, 2012, the Kandilli Observatory and Earthquake Research Institute (KOERI) and the Portuguese Institute for the Sea and Atmosphere (IPMA) joined other countries in the North-eastern Atlantic, the Mediterranean and Connected Seas (NEAM) region as participants in an international tsunami response exercise. The exercise, titled NEAMWave12, simulated widespread Tsunami Watch situations throughout the NEAM region. It is the first international exercise as such, in this region, where the UNESCO-IOC ICG/NEAMTWS tsunami warning chain has been tested to a full scale for the first time with different systems. One of the systems is developed in the project Collaborative, Complex, and Critical Decision-Support in Evolving Crises (TRIDEC) and has been validated in this exercise among others by KOERI and IPMA. In TRIDEC new developments in Information and Communication Technology (ICT) are used to extend the existing platform realising a component-based technology framework for building distributed tsunami warning systems for deployment, e.g. in the North-eastern Atlantic, the Mediterranean and Connected Seas (NEAM) region. The TRIDEC system will be implemented in three phases, each with a demonstrator. Successively, the demonstrators are addressing related challenges. The first and second phase system demonstrator, deployed at KOERI's crisis management room and deployed at IPMA has been designed and implemented, firstly, to support plausible scenarios for the Turkish NTWC and for the Portuguese NTWC to demonstrate the treatment of simulated tsunami threats with an essential subset of a NTWC. Secondly, the feasibility and the potentials of the implemented approach are demonstrated covering ICG/NEAMTWS standard operations as well as tsunami detection and alerting functions beyond ICG/NEAMTWS requirements. The demonstrator presented addresses information management and decision-support processes for hypothetical tsunami-related crisis situations in the context of the ICG/NEAMTWS NEAMWave12 exercise for the Turkish and Portuguese tsunami exercise scenarios. Impressions gained with the standards compliant TRIDEC system during the exercise will be reported. The system version presented is based on event-driven architecture (EDA) and service-oriented architecture (SOA) concepts and is making use of relevant standards of the Open Geospatial Consortium (OGC), the World Wide Web Consortium (W3C) and the Organization for the Advancement of Structured Information Standards (OASIS). In this way the system continuously gathers, processes and displays events and data coming from open sensor platforms to enable operators to quickly decide whether an early warning is necessary and to send personalized warning messages to the authorities and the population at large through a wide range of communication channels. The system integrates OGC Sensor Web Enablement (SWE) compliant sensor systems for the rapid detection of hazardous events, like earthquakes, sea level anomalies, ocean floor occurrences, and ground displacements. Using OGC Web Map Service (WMS) and Web Feature Service (WFS) spatial data are utilized to depict the situation picture. The integration of a simulation system to identify affected areas is considered using the OGC Web Processing Service (WPS). Warning messages are compiled and transmitted in the OASIS Common Alerting Protocol (CAP) together with addressing information defined via the OASIS Emergency Data Exchange Language - Distribution Element (EDXL-DE). This demonstration is linked with the talk 'Experiences with TRIDEC's Crisis Management Demonstrator in the Turkish NEAMWave12 exercise tsunami scenario' (EGU2013-2833) given in the session "Architecture of Future Tsunami Warning Systems" (NH5.6).

Near Field Modeling for the Maule Tsunami from DART, GPS and Finite Fault Solutions (Invited)

NASA Astrophysics Data System (ADS)

Arcas, D.; Chamberlin, C.; Lagos, M.; Ramirez-Herrera, M.; Tang, L.; Wei, Y.

2010-12-01

The earthquake and tsunami of February, 27, 2010 in central Chile has rekindled an interest in developing techniques to predict the impact of near field tsunamis along the Chilean coastline. Following the earthquake, several initiatives were proposed to increase the density of seismic, pressure and motion sensors along the South American trench, in order to provide field data that could be used to estimate tsunami impact on the coast. However, the precise use of those data in the elaboration of a quantitative assessment of coastal tsunami damage has not been clarified. The present work makes use of seismic, Deep-ocean Assessment and Reporting of Tsunamis (DART®) systems, and GPS measurements obtained during the Maule earthquake to initiate a number of tsunami inundation models along the rupture area by expressing different versions of the seismic crustal deformation in terms of NOAA’s tsunami unit source functions. Translation of all available real-time data into a feasible tsunami source is essential in near-field tsunami impact prediction in which an impact assessment must be generated under very stringent time constraints. Inundation results from each different source are then contrasted with field and tide gauge data by comparing arrival time, maximum wave height, maximum inundation and tsunami decay rate, using field data collected by the authors.

NOAA Propagation Database Value in Tsunami Forecast Guidance

NASA Astrophysics Data System (ADS)

Eble, M. C.; Wright, L. M.

2016-02-01

The National Oceanic and Atmospheric Administration (NOAA) Center for Tsunami Research (NCTR) has developed a tsunami forecasting capability that combines a graphical user interface with data ingestion and numerical models to produce estimates of tsunami wave arrival times, amplitudes, current or water flow rates, and flooding at specific coastal communities. The capability integrates several key components: deep-ocean observations of tsunamis in real-time, a basin-wide pre-computed propagation database of water level and flow velocities based on potential pre-defined seismic unit sources, an inversion or fitting algorithm to refine the tsunami source based on the observations during an event, and tsunami forecast models. As tsunami waves propagate across the ocean, observations from the deep ocean are automatically ingested into the application in real-time to better define the source of the tsunami itself. Since passage of tsunami waves over a deep ocean reporting site is not immediate, we explore the value of the NOAA propagation database in providing placeholder forecasts in advance of deep ocean observations. The propagation database consists of water elevations and flow velocities pre-computed for 50 x 100 [km] unit sources in a continuous series along all known ocean subduction zones. The 2011 Japan Tohoku tsunami is presented as the case study

Tsunami risk zoning in south-central Chile

NASA Astrophysics Data System (ADS)

Lagos, M.

2010-12-01

The recent 2010 Chilean tsunami revealed the need to optimize methodologies for assessing the risk of disaster. In this context, modern techniques and criteria for the evaluation of the tsunami phenomenon were applied in the coastal zone of south-central Chile as a specific methodology for the zoning of tsunami risk. This methodology allows the identification and validation of a scenario of tsunami hazard; the spatialization of factors that have an impact on the risk; and the zoning of the tsunami risk. For the hazard evaluation, different scenarios were modeled by means of numerical simulation techniques, selecting and validating the results that better fit with the observed tsunami data. Hydrodynamic parameters of the inundation as well as physical and socioeconomic vulnerability aspects were considered for the spatialization of the factors that affect the tsunami risk. The tsunami risk zoning was integrated into a Geographic Information System (GIS) by means of multicriteria evaluation (MCE). The results of the tsunami risk zoning show that the local characteristics and their location, together with the concentration of poverty levels, establish spatial differentiated risk levels. This information builds the basis for future applied studies in land use planning that tend to minimize the risk levels associated to the tsunami hazard. This research is supported by Fondecyt 11090210.

Tsunami hazard mitigation in tourism in the tropical and subtropical coastal areas: a case study in the Ryukyu Islands, southwest of Japan

NASA Astrophysics Data System (ADS)

Matsumoto, T.

2006-12-01

Life and economy (including tourism) in tropical and subtropical coastal areas, such as Okinawa Prefecture (Ryukyu) are highly relying on the sea. The sea has both "gentle" side to give people healing and "dangerous" side to kill people. If we are going to utilise the sea for marine tourism such as constructing resort facilities on the oceanfront, we should know all of the sea, including the both sides of the sea: especially the nature of tsunamis. And also we islanders should issue accurate information about the sea towards outsiders, especially tourists visiting the island. We have already learned a lesson about this issue from the Sumatra tsunami in 2004. However, measures against the tsunami disaster by marine tourism industry are still inadequate in these areas. The goal of tsunami hazard mitigation for those engaged in tourism industry in tropical and subtropical coastal areas should be as follows. (1) Preparedness against tsunamis: "Be aware of the characteristics of tsunamis." "Prepare tsunamis when you feel an earthquake." "Prepare tsunamis when an earthquake takes place somewhere in the world." (2) Maintenance of an exact tsunami hazard map under quantitative analyses of the characteristics of tsunamis: "Flooding areas by tsunami attacks are dependent not only on altitude but also on amplification and inundation due to the seafloor topography near the coast and the onland topographic relief." "Tsunami damage happens repeatedly." (3) Maintenance of a tsunami disaster prevention manual and training after the manual: "Who should do what in case of tsunamis?" "How should the resort hotel employees lead the guests to the safe place?" Such a policy for disaster prevention is discussed in the class of the general education of "Ocean Sciences" in University of the Ryukyus (UR) and summer school for high school students. The students (most of them are from Okinawa Prefecture) consider, discuss and make reports about what to do in case of tsunamis as an islander. Especially, students of Department of Tourism Sciences (DTS) are keen on the discussion and make excellent reports/proposals. Here, the author would also like to introduce some of them in the presentation.

Tsunami damage in the southern Kanto region from the 1703 Genroku Kanto earthquake

NASA Astrophysics Data System (ADS)

Muragishi, J.; Satake, K.

2014-12-01

The Genroku Kanto earthquake occurred on Dec. 31th, 1703 along the Sagami Trough where the Philippine Sea plate subducts beneath the continental plate. Hatori (1976) reported significant tsunami damage with estimated tsunami heights of 5 m along Kujukuri coast on the Pacific Ocean, and estimated the tsunami heights in the inner Tokyo Bay as approximately 2 m. In Tokyo Bay, there are no records that indicate the tsunami inundated residential areas, while some descriptions of tsunami are recorded in Edo, the former Tokyo. The notice from Edo City Commissioners to residences in Edo described that the tsunami came up to the upper-limit of Sumida River in Tokyo, where four major arrivals of tsunamis were reported. According to Saihen-onkoroku, tsunami came to Fukagawa, where one person was killed by throwing away from a boat affected by the tsunami. In Ichikawa along the coast of Chiba Prefecture in Tokyo Bay, there are historical records about the salt farm. The embankments were collapsed and the salt farm was ruined, while the tsunami damage is not described. At this location, the damage due to storm surge in 1680 is recorded in the same document. Although storm surge damage is recorded in detail, there are no records about the Genroku tsunami, suggesting that the tsunami damage, if any, is slighter than the storm surge. Along the Kujukui coast outside the Tokyo bay, the descriptions are not only damage to buildings or deaths but also an influx of sand brought by the tsunami which damaged the agricultural land. In summary, it became certain that the Genroku tsunami caused some damage in the inner Tokyo Bay area. In addition, we found that a wide range of farmland was suffered by influx of sand and crops could not grow well. Such a description may be able to contribute to the tsunami deposits in future research. This study was supported by the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters from the MEXT of Japan.

Implementation of the TsunamiReady Supporter Program in Puerto Rico

NASA Astrophysics Data System (ADS)

Flores Hots, V. E.; Vanacore, E. A.; Gonzalez Ruiz, W.; Gomez, G.

2016-12-01

The Puerto Rico Seismic Network (PRSN) manages the PR Tsunami Program (NTHMP), including the TsunamiReady Supporter Program. Through this program the PRSN helps private organizations, businesses, facilities or local government entities to willingly engage in tsunami planning and preparedness that meet some requirements established by the National Weather Service. TsunamiReady Supporter organizations are better prepared to respond to a tsunami emergency, developing a response plan (using a template that PRSN developed and provides), and reinforcing their communication systems including NOAA radio, RSS, and loud speakers to receive and disseminate the alerts issued by the NWS and the Tsunami Warning Centers (TWC). The planning and the communication systems added to the training that PRSN provides to the staff and employees, are intend to help visitors and employees evacuate the tsunami hazard zone to the nearest assembly point minimizing loss of life. Potential TsunamiReady Supporters include, but are not limited to, businesses, schools, churches, hospitals, malls, utilities, museums, beaches, and harbors. However, the traditional targets for such programs are primarily tourism sites and hotels where people unaware of the tsunami hazard may be present. In 2016 the Tsunami Ready Program guided four businesses to achieve the TsunamiReady Supporter recognition. Two facilities were hotels near or inside the evacuation zone. The other facilities were the first and only health center and supermarket to be recognized in the United States and US territories. Based on the experience of preparing the health center and supermarket sites, here we present two case studies of how the TsunamiReady Supporter Program can be applied to non-traditional facilities as well as how the application of this program to such facilities can improve tsunami hazard mitigation. Currently, we are working on expanding the application of this program to non-traditional facilities by working with a banking facility located in a tsunami evacuation zone increasing their capacity to manage a tsunami event and to reinforce the entity's involvement in developing a plan for their clients and employees to evacuate the area and head to a safe place.

Floating assembly of diatom Coscinodiscus sp. microshells.

PubMed

Wang, Yu; Pan, Junfeng; Cai, Jun; Zhang, Deyuan

2012-03-30

Diatoms have silica frustules with transparent and delicate micro/nano scale structures, two dimensional pore arrays, and large surface areas. Although, the diatom cells of Coscinodiscus sp. live underwater, we found that their valves can float on water and assemble together. Experiments show that the convex shape and the 40 nm sieve pores of the valves allow them to float on water, and that the buoyancy and the micro-range attractive forces cause the valves to assemble together at the highest point of water. As measured by AFM calibrated glass needles fixed in manipulator, the buoyancy force on a single floating valve may reach up to 10 μN in water. Turning the valves over, enlarging the sieve pores, reducing the surface tension of water, or vacuum pumping may cause the floating valves to sink. After the water has evaporated, the floating valves remained in their assembled state and formed a monolayer film. The bonded diatom monolayer may be valuable in studies on diatom based optical devices, biosensors, solar cells, and batteries, to better use the optical and adsorption properties of frustules. The floating assembly phenomenon can also be used as a self-assembly method for fabricating monolayer of circular plates. Copyright © 2012 Elsevier Inc. All rights reserved.

Earthquake and submarine landslide tsunamis: how can we tell the difference? (Invited)

NASA Astrophysics Data System (ADS)

Tappin, D. R.; Grilli, S. T.; Harris, J.; Geller, R. J.; Masterlark, T.; Kirby, J. T.; Ma, G.; Shi, F.

2013-12-01

Several major recent events have shown the tsunami hazard from submarine mass failures (SMF), i.e., submarine landslides. In 1992 a small earthquake triggered landslide generated a tsunami over 25 meters high on Flores Island. In 1998 another small, earthquake-triggered, sediment slump-generated tsunami up to 15 meters high devastated the local coast of Papua New Guinea killing 2,200 people. It was this event that led to the recognition of the importance of marine geophysical data in mapping the architecture of seabed sediment failures that could be then used in modeling and validating the tsunami generating mechanism. Seabed mapping of the 2004 Indian Ocean earthquake rupture zone demonstrated, however, that large, if not great, earthquakes do not necessarily cause major seabed failures, but that along some convergent margins frequent earthquakes result in smaller sediment failures that are not tsunamigenic. Older events, such as Messina, 1908, Makran, 1945, Alaska, 1946, and Java, 2006, all have the characteristics of SMF tsunamis, but for these a SMF source has not been proven. When the 2011 tsunami struck Japan, it was generally assumed that it was directly generated by the earthquake. The earthquake has some unusual characteristics, such as a shallow rupture that is somewhat slow, but is not a 'tsunami earthquake.' A number of simulations of the tsunami based on an earthquake source have been published, but in general the best results are obtained by adjusting fault rupture models with tsunami wave gauge or other data so, to the extent that they can model the recorded tsunami data, this demonstrates self-consistency rather than validation. Here we consider some of the existing source models of the 2011 Japan event and present new tsunami simulations based on a combination of an earthquake source and an SMF mapped from offshore data. We show that the multi-source tsunami agrees well with available tide gauge data and field observations and the wave data from offshore buoys, and that the SMF generated the large runups in the Sanriku region (northern Tohoku). Our new results for the 2011 Tohoku event suggest that care is required in using tsunami wave and tide gauge data to both model and validate earthquake tsunami sources. They also suggest a potential pitfall in the use of tsunami waveform inversion from tide gauges and buoys to estimate the size and spatial characteristics of earthquake rupture. If the tsunami source has a significant SMF component such studies may overestimate earthquake magnitude. Our seabed mapping identifies other large SMFs off Sanriku that have the potential to generate significant tsunamis and which should be considered in future analyses of the tsunami hazard in Japan. The identification of two major SMF-generated tsunamis (PNG and Tohoku), especially one associated with a M9 earthquake, is important in guiding future efforts at forecasting and mitigating the tsunami hazard from large megathrust plus SMF events both in Japan and globally.

Impacting load control of floating supported friction plate and its experimental verification

NASA Astrophysics Data System (ADS)

Ning, Keyan; Wang, Yu; Huang, Dingchuan; Yin, Lei

2017-05-01

Friction plates are key components in automobile transmission system. Unfortunately, due to the tough working condition i.e. high impact, high temperature, fracture and plastic deformation are easily observed in friction plates. In order to reduce the impact load and increase the impact resistance and life span of the friction plate. This paper presents a variable damping design method and structure, by punching holes in the key position of the friction plate and filling it with damping materials, the impact load of the floating support friction plate can be controlled. Simulation is applied to study the effect of the position and number of damping holes on tooth root stress. Furthermore, physic test was designed and conducted to validate the correctness and effectiveness of the proposed method. Test result shows that the impact load of the new structure is reduced by 40% and its fatigue life is 4.7 times larger. The new structure provides a new way for floating supported friction plates design.

NOAA/West coast and Alaska Tsunami warning center Atlantic Ocean response criteria

USGS Publications Warehouse

Whitmore, P.; Refidaff, C.; Caropolo, M.; Huerfano-Moreno, V.; Knight, W.; Sammler, W.; Sandrik, A.

2009-01-01

West Coast/Alaska Tsunami Warning Center (WCATWC) response criteria for earthquakesoccurring in the Atlantic and Caribbean basins are presented. Initial warning center decisions are based on an earthquake's location, magnitude, depth, distance from coastal locations, and precomputed threat estimates based on tsunami models computed from similar events. The new criteria will help limit the geographical extent of warnings and advisories to threatened regions, and complement the new operational tsunami product suite. Criteria are set for tsunamis generated by earthquakes, which are by far the main cause of tsunami generation (either directly through sea floor displacement or indirectly by triggering of sub-sea landslides).The new criteria require development of a threat data base which sets warning or advisory zones based on location, magnitude, and pre-computed tsunami models. The models determine coastal tsunami amplitudes based on likely tsunami source parameters for a given event. Based on the computed amplitude, warning and advisory zones are pre-set.

Highly variable recurrence of tsunamis in the 7,400 years before the 2004 Indian Ocean tsunami

PubMed Central

Rubin, Charles M.; Horton, Benjamin P.; Sieh, Kerry; Pilarczyk, Jessica E.; Daly, Patrick; Ismail, Nazli; Parnell, Andrew C.

2017-01-01

The devastating 2004 Indian Ocean tsunami caught millions of coastal residents and the scientific community off-guard. Subsequent research in the Indian Ocean basin has identified prehistoric tsunamis, but the timing and recurrence intervals of such events are uncertain. Here we present an extraordinary 7,400 year stratigraphic sequence of prehistoric tsunami deposits from a coastal cave in Aceh, Indonesia. This record demonstrates that at least 11 prehistoric tsunamis struck the Aceh coast between 7,400 and 2,900 years ago. The average time period between tsunamis is about 450 years with intervals ranging from a long, dormant period of over 2,000 years, to multiple tsunamis within the span of a century. Although there is evidence that the likelihood of another tsunamigenic earthquake in Aceh province is high, these variable recurrence intervals suggest that long dormant periods may follow Sunda megathrust ruptures as large as that of the 2004 Indian Ocean tsunami. PMID:28722009

Highly variable recurrence of tsunamis in the 7,400 years before the 2004 Indian Ocean tsunami.

PubMed

Rubin, Charles M; Horton, Benjamin P; Sieh, Kerry; Pilarczyk, Jessica E; Daly, Patrick; Ismail, Nazli; Parnell, Andrew C

2017-07-19

The devastating 2004 Indian Ocean tsunami caught millions of coastal residents and the scientific community off-guard. Subsequent research in the Indian Ocean basin has identified prehistoric tsunamis, but the timing and recurrence intervals of such events are uncertain. Here we present an extraordinary 7,400 year stratigraphic sequence of prehistoric tsunami deposits from a coastal cave in Aceh, Indonesia. This record demonstrates that at least 11 prehistoric tsunamis struck the Aceh coast between 7,400 and 2,900 years ago. The average time period between tsunamis is about 450 years with intervals ranging from a long, dormant period of over 2,000 years, to multiple tsunamis within the span of a century. Although there is evidence that the likelihood of another tsunamigenic earthquake in Aceh province is high, these variable recurrence intervals suggest that long dormant periods may follow Sunda megathrust ruptures as large as that of the 2004 Indian Ocean tsunami.

Near-field hazard assessment of March 11, 2011 Japan Tsunami sources inferred from different methods

USGS Publications Warehouse

Wei, Y.; Titov, V.V.; Newman, A.; Hayes, G.; Tang, L.; Chamberlin, C.

2011-01-01

Tsunami source is the origin of the subsequent transoceanic water waves, and thus the most critical component in modern tsunami forecast methodology. Although impractical to be quantified directly, a tsunami source can be estimated by different methods based on a variety of measurements provided by deep-ocean tsunameters, seismometers, GPS, and other advanced instruments, some in real time, some in post real-time. Here we assess these different sources of the devastating March 11, 2011 Japan tsunami by model-data comparison for generation, propagation and inundation in the near field of Japan. This study provides a comparative study to further understand the advantages and shortcomings of different methods that may be potentially used in real-time warning and forecast of tsunami hazards, especially in the near field. The model study also highlights the critical role of deep-ocean tsunami measurements for high-quality tsunami forecast, and its combination with land GPS measurements may lead to better understanding of both the earthquake mechanisms and tsunami generation process. ?? 2011 MTS.

U.S. States and Territories National Tsunami Hazard Assessment: Historical record and sources for waves – Update

USGS Publications Warehouse

Dunbar, Paula K.; Weaver, Craig S.

2015-01-01

The first U.S. Tsunami Hazard Assessment (Dunbar and Weaver, 2008) was prepared at the request of the National Tsunami Hazard Mitigation Program (NTHMP). The NTHMP is a partnership formed between federal and state agencies to reduce the impact of tsunamis through hazard assessment, warning guidance, and mitigation. The assessment was conducted in response to a 2005 joint report by the Sub-Committee on Disaster Reduction and the U.S. Group on Earth Observations entitled Tsunami Risk Reduction for the United States: A Framework for Action. The first specific action called for in the Framework was to “develop standardized and coordinated tsunami hazard and risk assessments for all coastal regions of the United States and its territories.” Since the first assessment, there have been a number of very significant tsunamis, including the 2009 Samoa, 2010 Chile, and 2011 Japan tsunamis. As a result, the NTHMP requested an update of the U.S. tsunami hazard assessment.

Highly variable recurrence of tsunamis in the 7,400 years before the 2004 Indian Ocean tsunami

NASA Astrophysics Data System (ADS)

Rubin, Charles M.; Horton, Benjamin P.; Sieh, Kerry; Pilarczyk, Jessica E.; Daly, Patrick; Ismail, Nazli; Parnell, Andrew C.

2017-07-01

The devastating 2004 Indian Ocean tsunami caught millions of coastal residents and the scientific community off-guard. Subsequent research in the Indian Ocean basin has identified prehistoric tsunamis, but the timing and recurrence intervals of such events are uncertain. Here we present an extraordinary 7,400 year stratigraphic sequence of prehistoric tsunami deposits from a coastal cave in Aceh, Indonesia. This record demonstrates that at least 11 prehistoric tsunamis struck the Aceh coast between 7,400 and 2,900 years ago. The average time period between tsunamis is about 450 years with intervals ranging from a long, dormant period of over 2,000 years, to multiple tsunamis within the span of a century. Although there is evidence that the likelihood of another tsunamigenic earthquake in Aceh province is high, these variable recurrence intervals suggest that long dormant periods may follow Sunda megathrust ruptures as large as that of the 2004 Indian Ocean tsunami.

Tsunami Hazard, Vulnerability and Risk assessment for the coast of Oman

NASA Astrophysics Data System (ADS)

Gonzalez, Mauricio; Aniel-Quiroga, Íñigo; Aguirre-Ayerbe, Ignacio; Álvarez-Gómez, José Antonio; MArtínez, Jara; Gonzalez-Riancho, Pino; Fernandez, Felipe; Medina, Raúl; Al-Yahyai, Sultan

2016-04-01

Tsunamis are relatively infrequent phenomena representing a greater threat than earthquakes, hurricanes and tornadoes, and causing the loss of thousands of human lives and extensive damage to coastal infrastructures around the world. Advances in the understanding and prediction of tsunami impacts allow the development of new methodologies in this field. This work presents the methodology that has been followed for developing the tsunami hazard, vulnerability and risk assessment for the coast of Oman, including maps containing the results of the process. Oman is located in the south eastern corner of the Arabian Peninsula and of the Arabian plate, in front of the Makran Subduction Zone (MSZ), which is the major source of earthquakes in the eastern border of the Arabian plate and Oman (Al-Shaqsi, 2012). There are at least three historical tsunamis assigned to seismic origin in the MSZ (Heidarzadeh et al., 2008; Jordan, 2008). These events show the high potential for tsunami generation of the MSZ, being one of the most tsunamigenic zones in the Indian Ocean. For the tsunami hazard assessment, worst potential cases have been selected, as well as the historical case of 1945, when an 8.1 earthquake generated a tsunami affecting the coast of Oman, and prompting 4000 casualties in the countries of the area. These scenarios have been computationally simulated in order to get tsunami hazard maps, including flooding maps. These calculations have been carried out at national and local scale, in 9 municipalities all along the coast of Oman, including the cities of Sohar, Wudam, Sawadi, Muscat, Quriyat, Sur, Masirah, Al Duqm, and Salalah. Using the hazard assessment as input, this work presents as well an integrated framework for the tsunami vulnerability and risk assessment carried out in the Sultanate of Oman. This framework considers different dimensions (human, structural) and it is developed at two different spatial resolutions, national and local scale. The national vulnerability assessment is carried out for the entire Oman coastal area comprising 30 coastal wilayats, whereas the local sensitivity assessment is performed for the 9 coastal study areas. This work also connects vulnerability-risk assessment results to site-specific and target-oriented risk reduction measures. Results identify high risk areas along the coast of Oman in which measures for risk reduction are proposed. The identification and prioritization of mitigation measures were supported by a panel of local and international experts developed during a Risk Assessment Workshop held in Oman and a handbook containing the mitigation measures at national and local scales was developed and delivered to the stakeholders. We would like to thank the Ministry of Transport and Communications of the Government of the Sultanate of Oman (MOTC), Directorate General of Meteorology and Air Navigation (DGMAN), Public Authority for Civil Aviation (PACA), for supporting and funding this project and the collaboration of the IOC-UNESCO personnel. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe).

Hydro- and morphodynamic tsunami simulations for the Ambrakian Gulf (Greece) and comparison with geoscientific field traces

NASA Astrophysics Data System (ADS)

Röbke, B. R.; Schüttrumpf, H.; Vött, A.

2018-04-01

In order to derive local tsunami risks for a particular coast, hydro- and morphodynamic numerical models that are calibrated and compared with sedimentary field data of past tsunami impacts have proven very effective. While this approach has widely been used with regard to recent tsunami events, comparable investigations into pre-/historical tsunami impacts hardly exist, which is the objective of this study focusing on the Ambrakian Gulf in northwestern Greece. The Ambrakian Gulf is located in the most active seismotectonic and by this most tsunamigenic area of the Mediterranean. Accordingly, palaeotsunami field studies have revealed repeated tsunami impacts on the gulf during the past 8000 yr. The current study analyses 151 vibracores of the Ambrakian Gulf coast in order to evaluate tsunami signals in the sedimentary record. Based on a hydro- and morphodynamic numerical model of the study area, various tsunami waves are simulated with the aim of finding scenarios that compare favourably with tsunami deposits detected in the field. Both, field data and simulation results suggest a decreasing tsunami influence from the western to the eastern Ambrakian Gulf. Various scenarios are needed to explain tsunami deposits in different parts of the gulf. Whereas shorter period tsunami waves (T = 30 min) from the south and west compare favourably with field data in the western gulf, longer period waves (T = 80 min) from a western direction show the best agreement with tsunami sediments detected in southwestern Aktio Headland and in the more central parts of the Ambrakian Gulf including Lake Voulkaria. Tsunamis from the southwest generally do not accord with field traces. Besides the spatial sediment distribution, the numerical model accurately reflects the sedimentary composition of the detected event deposits and reproduces a number of essential features typical of tsunamites, which were also observed in the field. Such include fining- and thinning-landward and the marine character of the deposits. By contrast, the simulated thickness of tsunami sediments usually lags behind the observed thickness in the field and some event layers cannot be explained by any of the simulated scenarios. Regarding the frequency of past tsunami events and their spatial dimensions indicated by both field data and simulation results, a high tsunami risk has to be derived for the Ambrakian Gulf.

Tsunami Source Identification on the 1867 Tsunami Event Based on the Impact Intensity

NASA Astrophysics Data System (ADS)

Wu, T. R.

2014-12-01

The 1867 Keelung tsunami event has drawn significant attention from people in Taiwan. Not only because the location was very close to the 3 nuclear power plants which are only about 20km away from the Taipei city but also because of the ambiguous on the tsunami sources. This event is unique in terms of many aspects. First, it was documented on many literatures with many languages and with similar descriptions. Second, the tsunami deposit was discovered recently. Based on the literatures, earthquake, 7-meter tsunami height, volcanic smoke, and oceanic smoke were observed. Previous studies concluded that this tsunami was generated by an earthquake with a magnitude around Mw7.0 along the Shanchiao Fault. However, numerical results showed that even a Mw 8.0 earthquake was not able to generate a 7-meter tsunami. Considering the steep bathymetry and intense volcanic activities along the Keelung coast, one reasonable hypothesis is that different types of tsunami sources were existed, such as the submarine landslide or volcanic eruption. In order to confirm this scenario, last year we proposed the Tsunami Reverse Tracing Method (TRTM) to find the possible locations of the tsunami sources. This method helped us ruling out the impossible far-field tsunami sources. However, the near-field sources are still remain unclear. This year, we further developed a new method named 'Impact Intensity Analysis' (IIA). In the IIA method, the study area is divided into a sequence of tsunami sources, and the numerical simulations of each source is conducted by COMCOT (Cornell Multi-grid Coupled Tsunami Model) tsunami model. After that, the resulting wave height from each source to the study site is collected and plotted. This method successfully helped us to identify the impact factor from the near-field potential sources. The IIA result (Fig. 1) shows that the 1867 tsunami event was a multi-source event. A mild tsunami was trigged by a Mw7.0 earthquake, and then followed by the submarine landslide or volcanic events. A near-field submarine landslide and landslide at Mien-Hwa Canyon were the most possible scenarios. As for the volcano scenarios, the volcanic eruption located about 10 km away from Keelung with 2.5x108 m3 disturbed water volume might be a candidate. The detailed scenario results will be presented in the full paper.

The Contribution of Coseismic Displacements due to Splay Faults Into the Local Wavefield of the 1964 Alaska Tsunami

NASA Astrophysics Data System (ADS)

Suleimani, E.; Ruppert, N.; Fisher, M.; West, D.; Hansen, R.

2008-12-01

The Alaska Earthquake Information Center conducts tsunami inundation mapping for coastal communities in Alaska. For many locations in the Gulf of Alaska, the 1964 tsunami generated by the Mw9.2 Great Alaska earthquake may be the worst-case tsunami scenario. We use the 1964 tsunami observations to verify our numerical model of tsunami propagation and runup, therefore it is essential to use an adequate source function of the 1964 earthquake to reduce the level of uncertainty in the modeling results. It was shown that the 1964 co-seismic slip occurred both on the megathrust and crustal splay faults (Plafker, 1969). Plafker (2006) suggested that crustal faults were a major contributor to vertical displacements that generated local tsunami waves. Using eyewitness arrival times of the highest observed waves, he suggested that the initial tsunami wave was higher and closer to the shore, than if it was generated by slip on the megathrust. We conduct a numerical study of two different source functions of the 1964 tsunami to test whether the crustal splay faults had significant effects on local tsunami runup heights and arrival times. The first source function was developed by Johnson et al. (1996) through joint inversion of the far-field tsunami waveforms and geodetic data. The authors did not include crustal faults in the inversion, because the contribution of these faults to the far-field tsunami was negligible. The second is the new coseismic displacement model developed by Suito and Freymueller (2008, submitted). This model extends the Montague Island fault farther along the Kenai Peninsula coast and thus reduces slip on the megathrust in that region. We also use an improved geometry of the Patton Bay fault based on the deep crustal seismic reflection and earthquake data. We propagate tsunami waves generated by both source models across the Pacific Ocean and record wave amplitudes at the locations of the tide gages that recorded the 1964 tsunami. As expected, the two sources produce very similar waveforms in the far field that are also in good agreement with the tide gage records. In order to study the near-field tsunami effects, we will construct embedded telescoping bathymetry grids around tsunami generation area to calculate tsunami arrival times and sea surface heights for both source models of the 1964 earthquake, and use available observation data to verify the model results.

Evaluation of Tsunami Hazards in Kuwait from Possible Earthquake and Landslide Sources considering Effect of Natural Tide

NASA Astrophysics Data System (ADS)

Latcharote, P.

2016-12-01

Kuwait is one of the most important oil producers to the world and most of population and many vital facilities are located along the coasts. However, even with low or unknown tsunami risk, it is important to investigate tsunami hazards in this country to ensure safety of life and sustain the global economy. This study aimed to evaluate tsunami hazards along the coastal areas of Kuwait from both earthquake and landslide sources using numerical modeling. Tsunami generation and propagation was simulated using the two-layer model and the TUNAMI model. Four cases of earthquake scenarios are expected to generate tsunami along the Makran Subduction Zone (MSZ) based on historical events and worst cases possible to simulate tsunami propagation to the coastal areas of the Arabian Gulf. Case 1 (Mw 8.3) and Case 2 (Mw 8.3) are the replication of the 1945 Makran earthquake, whereas Case 3 (Mw 8.6) and Case 4 (Mw 9.0) are the worst-case scenarios. Tsunami numerical simulation was modelled with mesh size 30 arc-second using bathymetry and topography data from GEBCO. Preliminary results suggested that tsunamis generated by Case 1 and Case 2 will impose very small effects to Kuwait (< 0.1 m) while Case 3 and Case 4 can generate maximum tsunami amplitude up to 0.3 m to 1.0 m after 12 hours from the earthquake. In addition, this study considered tsunamis generated by landslide along the opposite Iranian coast of Kuwait bay. To preliminarily assess tsunami hazards, coastal landslides were assumed occurred at the volume of 1.0-2.0 km3 at three possible locations from their topographic features. The preliminary results revealed that tsunami generated by coastal landslides could impose a significant tsunami impact to Kuwait having maximum tsunami amplitude at the Falika Island in front of Kuwait bay and Azzour power and desalination plant about 0.5 m- 1.1 m depending on landslide volume and energy dissipation. Future works will include more accuracy of tsunami numerical simulation with higher resolution of bathymetry and topography data in order to investigate tsunami inundation. Furthermore, detailed analysis on possible landslide sources will be performed by means of 3D-slope stability analysis in order to know the exact locations and landslide volumes taking into account the geological conditions, such as surface elevation and soil property data.

A Self-Powered Fast-Sampling Profiling Float in support of a Mesoscale Ocean Observing System in the Western North Pacific

NASA Astrophysics Data System (ADS)

Valdez, T.; Chao, Y.; Davis, R. E.; Jones, J.

2012-12-01

This talk will describe a new self-powered profiling float that can perform fast sampling over the upper ocean for long durations in support of a mesoscale ocean observing system in the Western North Pacific. The current state-of-the-art profiling floats can provide several hundreds profiles for the upper ocean every ten days. To quantify the role of the upper ocean in modulating the development of Typhoons requires at least an order of magnitude reduction for the sampling interval. With today's profiling float and battery technology, a fast sampling of one day or even a few hours will reduce the typical lifetime of profiling floats from years to months. Interactions between the ocean and typhoons often involves mesoscale eddies and fronts, which require a dense array of floats to reveal the 3-dimensional structure. To measure the mesoscale ocean over a large area like the Western North Pacific therefore requires a new technology that enables fast sampling and long duration at the same time. Harvesting the ocean renewable energy associated with the vertical temperature differentials has the potential to power profiling floats with fast sampling over long durations. Results from the development and deployment of a prototype self-powered profiling float (known as SOLO-TREC) will be presented. With eight hours sampling in the upper 500 meters, the upper ocean temperature and salinity reveal pronounced high frequency variations. Plans to use the SOLO-TREC technology in support of a dense array of fast sampling profiling floats in the Western North Pacific will be discussed.

Tsunami Early Warning via a Physics-Based Simulation Pipeline

NASA Astrophysics Data System (ADS)

Wilson, J. M.; Rundle, J. B.; Donnellan, A.; Ward, S. N.; Komjathy, A.

2017-12-01

Through independent efforts, physics-based simulations of earthquakes, tsunamis, and atmospheric signatures of these phenomenon have been developed. With the goal of producing tsunami forecasts and early warning tools for at-risk regions, we join these three spheres to create a simulation pipeline. The Virtual Quake simulator can produce thousands of years of synthetic seismicity on large, complex fault geometries, as well as the expected surface displacement in tsunamigenic regions. These displacements are used as initial conditions for tsunami simulators, such as Tsunami Squares, to produce catalogs of potential tsunami scenarios with probabilities. Finally, these tsunami scenarios can act as input for simulations of associated ionospheric total electron content, signals which can be detected by GNSS satellites for purposes of early warning in the event of a real tsunami. We present the most recent developments in this project.

Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

NASA Astrophysics Data System (ADS)

Ando, M.; Ishida, M.; Hayashi, Y.; Mizuki, C.; Nishikawa, Y.; Tu, Y.

2013-09-01

One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake) (Mw = 9.0) were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

Display of historical and hypothetical tsunami on the coast of Sakhalin Island

NASA Astrophysics Data System (ADS)

Kostenko, Irina; Zaytsev, Andrey; Kurkin, Andrey; Yalciner, Ahmet

2014-05-01

Tsunami waves achieve the coast of the Sakhalin Island and their sources are located in the Japan Sea, in the Okhotsk Sea, in Kuril Islands region and in the Pacific Ocean. Study of tsunami generation characteristics and its propagation allows studying display of the tsunami on the various parts of the island coast. For this purpose the series of computational experiments of some historical tsunamis was carried out. Their sources located in Japan Sea and Kuril Islands region. The simulation results are compared with the observations. Analysis of all recorded historical tsunami on coast of Sakhalin Island was done. To identify the possible display of the tsunami on the coast of Sakhalin Island the series of computational experiments of hypothetical tsunamis was carried out. Their sources located in the Japan Sea and in the Okhotsk Sea. There were used hydrodynamic sources. There were used different parameters of sources (length, width, height, raising and lowering of sea level), which correspond to earthquakes of various magnitudes. The analysis of the results was carried out. Pictures of the distribution of maximum amplitudes from each tsunami were done. Areas of Okhotsk Sea, Japan Sea and offshore strip of Sakhalin Island with maximum tsunami amplitudes were defined. Graphs of the distribution of maximum tsunami wave heights along the coast of the Sakhalin Island were plotted. Based on shallow-water equation tsunami numerical code NAMI DANCE was used for numerical simulations. This work was supported by ASTARTE project.

How Do Tides and Tsunamis Interact in a Highly Energetic Channel? The Case of Canal Chacao, Chile

NASA Astrophysics Data System (ADS)

Winckler, Patricio; Sepúlveda, Ignacio; Aron, Felipe; Contreras-López, Manuel

2017-12-01

This study aims at understanding the role of tidal level, speed, and direction in tsunami propagation in highly energetic tidal channels. The main goal is to comprehend whether tide-tsunami interactions enhance/reduce elevation, currents speeds, and arrival times, when compared to pure tsunami models and to simulations in which tides and tsunamis are linearly superimposed. We designed various numerical experiments to compute the tsunami propagation along Canal Chacao, a highly energetic channel in the Chilean Patagonia lying on a subduction margin prone to megathrust earthquakes. Three modeling approaches were implemented under the same seismic scenario: a tsunami model with a constant tide level, a series of six composite models in which independent tide and tsunami simulations are linearly superimposed, and a series of six tide-tsunami nonlinear interaction models (full models). We found that hydrodynamic patterns differ significantly among approaches, being the composite and full models sensitive to both the tidal phase at which the tsunami is triggered and the local depth of the channel. When compared to full models, composite models adequately predicted the maximum surface elevation, but largely overestimated currents. The amplitude and arrival time of the tsunami-leading wave computed with the full model was found to be strongly dependent on the direction of the tidal current and less responsive to the tide level and the tidal current speed. These outcomes emphasize the importance of addressing more carefully the interactions of tides and tsunamis on hazard assessment studies.

Verification of Reproduction Simulation of the 2011 Great East Japan Tsunami Using Time-Stamp Data

NASA Astrophysics Data System (ADS)

Honma, Motohiro; Ushiyama, Motoyuki

2014-05-01

In the 2011 off the pacific coast of Tohoku earthquake tsunami, the significant damage and loss of lives were caused by large tsunami in the pacific coastal areas of the northern Japan. It is important to understand the situation of tsunami inundation in detail in order to establish the effective measures of disaster prevention. In this study, we calculated the detailed tsunami inundation simulation of Rikuzentakata city and verified the simulation results using not only the static observed data such as inundation area and tsunami height estimated by traces but also time stamp data which were recorded to digital camera etc. We calculated the tsunami simulation by non-linear long-wave theory using the staggered grid and leap flog scheme. We used Fujii and Satake (2011)'s model ver.4.2 as the tsunami source. The inundation model of Rikuzentakata city was constructed by fine ground level data of 10m mesh. In this simulation, the shore and river banks were set in boundary of calculation mesh. At that time, we have calculated two patterns of simulation, one condition is that a bank doesn't collapse even if tsunami overflows on it, another condition is that a bank collapses if tsunami overflows on it and its discharge exceeds the threshold. We can use the inundation area data, which was obtained by Geospatial Information Authority of Japan (GSI), and height data of tsunami trace, which were obtained by the 2011 Tohoku Earthquake Joint Survey (TTJS) group, as "static" verification data. Comparing the inundation area of simulation result with its observation by GSI, both areas are matched very well. And then, correlation coefficient between tsunami height data resulted from simulation and observed by TTJS is 0.756. In order to verify tsunami arrival time, we used the time stamp data which were recorded to digital camera etc. by citizens. Ushiyama and Yokomaku (2012) collected these tsunami stamp data and estimated the arrival time in Rikuzentakata city. We compared the arrival time resulted from tsunami simulation with estimated by Ushiyama and Yokomaku (2012) for some major points. The arrival time is earlier 2-4 minutes in the condition that a bank collapses when tsunami overflows and its discharge exceeds 0.05m2/s at each mesh boundary than in the condition that a bank doesn't collapse. And, on the whole the arrival time estimated from time stamp data is in accord with the result which were calculated in the condition that a bank collapse. We could verify reproducibility about not only the final tsunami inundation situation but also the temporal change of tsunami inundation situation by using the time stamp data. Acknowledgement In this study, we used tsunami trace data obtained by The 2011 Tohoku Earthquake Tsunami Joint Survey (TTJS) Group. Reference 1) Fujii and Satake: Tsunami Source of the Off Tohoku-Pacific Earthquake on March 11, 2011, http://iisee.kenken.go.jp/staff/fujii/OffTohokuPacific2011/tsunami_ja_ver4.2and4.6.html, 2011. 2) Ushiyama and Yokomaku: Estimation of situation in Rikuzentakata city just before tsunami attack based on time stamp data, J.JSNDS31-1, pp.47-58, 2012.

The Knowledge Capsules: Very Short Films on Earth Science for Mainstream Audiences

NASA Astrophysics Data System (ADS)

Kerlow, Isaac

2015-04-01

The Knowledge Capsules are outreach and communication videos that present practical science research to mainstream audiences and take viewers on a journey into different aspects of Earth science and natural hazards. The innovative shorts are the result of an interdisciplinary development and production process. They include a combination of interviews, visualizations of scientific research, and documentation of fieldwork. They encapsulate research insights about volcanoes, tsunamis, and climate change in Southeast Asia. These short films were actively distributed free-of-charge during 2012-2014 and all of them are available online. The paper provides an overview of the motivations, process and accomplished results. Our approach for producing the Knowledge Capsules includes: an engaging mix of information and a fresh delivery style, a style suitable for a primary audience of non-scientists, a simple but experientially rich production style, Diagrams and animations based on the scientists' visuals, and a running time between five and twenty minutes. The completed Knowledge Capsules include: "Coastal Science" on Coastal Hazards, "The Ratu River Expedition" on Structural Geology, "Forensic Volcano Petrology by Fidel Costa, Volcano Petrology, "A Tale of Two Tsunamis" on Tsunami Stratigraphy, "Unlocking Climate Secrets" on Marine Geochemistry, and "Earth Girl 2: A Casual Strategy Game to Prepare for the Tsunami" on Natural Hazards and Science Outreach.

Atmospheric resonances of the Rayleigh and tsunami normal modes and its sensitivity to local time and geographical location.

NASA Astrophysics Data System (ADS)

Rakoto, V.; Astafyeva, E.; Lognonne, P. H.

2017-12-01

It is known that natural hazard events, such as earthquakes, tsunamis, volcano eruptions, etc. can generate atmospheric/ionospheric perturbations. During earthquakes, vertical displacements of the ground or of the ocean floor generate acoustic-gravity waves that further propagate upward in the upper atmosphere and ionosphere. In turn, tsunamis propagating in the open sea, generate gravity waves which propagate obliquely and reach the ionosphere in 45-60 min. The properties of the atmospheric "channel" in the vertical and oblique propagation depend on a variety of factors such as solar and geomagnetic conditions, latitude, local time, season, and their influence on propagation and properties of co-seismic and co-tsunamic perturbations is not well understood yet. In this work, we use present a detailed study of the coupling efficiency between solid earth, ocean and atmosphere. For this purpose, we use the normal mode technique extended to the whole solid Earth-ocean-atmosphere system. In our study, we focus on the Rayleigh modes (solid modes) and tsunami modes (oceanic modes). As the normal modes amplitude are also depending on the spatial and temporal variation of the structure of the atmosphere, we also performed a sensitivity study location of the normal modes amplitude with local time and geographical position.

High resolution tsunami modelling for the evaluation of potential risk areas in Setúbal (Portugal)

NASA Astrophysics Data System (ADS)

Ribeiro, J.; Silva, A.; Leitão, P.

2011-08-01

The use of high resolution hydrodynamic modelling to simulate the potential effects of tsunami events can provide relevant information about the most probable inundation areas. Moreover, the consideration of complementary data such as the type of buildings, location of priority equipment, type of roads, enables mapping of the most vulnerable zones, computing of the expected damage on man-made structures, constrain of the definition of rescue areas and escape routes, adaptation of emergency plans and proper evaluation of the vulnerability associated with different areas and/or equipment. Such an approach was used to evaluate the specific risks associated with a potential occurrence of a tsunami event in the region of Setúbal (Portugal), which was one of the areas most seriously affected by the 1755 tsunami. In order to perform an evaluation of the hazard associated with the occurrence of a similar event, high resolution wave propagation simulations were performed considering different potential earthquake sources with different magnitudes. Based on these simulations, detailed inundation maps associated with the different events were produced. These results were combined with the available information on the vulnerability of the local infrastructures (building types, roads and streets characteristics, priority buildings) in order to impose restrictions in the production of high-scale potential damage maps, escape routes and emergency routes maps.

Effects of high-temperature gas dealkalization on surface mechanical properties of float glass

NASA Astrophysics Data System (ADS)

Senturk, Ufuk

The surface topography, and the near-surface structure and mechanical property changes on float glass, that was treated in atmospheres containing SOsb2, HCl, and 1,1 difluoroethane (DFE) gases, at temperatures in the glass transition region, were studied. Structure was investigated using surface sensitive infrared spectroscopy techniques (attenuated total reflectance (ATR) and diffuse reflectance (DRIFT)) and the topography was evaluated using atomic force microscopy (AFM). The results obtained from the two FTIR methods were in agreement with each other. Mechanical property characteristics of the surface were determined by measuring microhardness using a recording microindentation set-up. A simple analysis performed on the three hardness calculation methods-LVH, LVHsb2, and Lsb2VH-indicated that LVH and LVHsb2 are less effected by measurement errors and are better suited for the calculation of hardness. Contact damage characteristics of the treated glass was also studied by monitoring the crack initiation behavior during indentation, using acoustic emission. The results of the studies, aiming for the understanding of the structure, topography, and hardness property changes indicate that the treatment parameters-temperature, time, and treatment atmosphere conditions-are significant factors influencing these properties. The analysis of these results suggest a relation to exist between the three properties. This relation is used in understanding the surface mechanical properties of the treated float glasses. The difference in the thermal expansion coefficients between the dealkalized surface and bulk, the nature of surface structure changes, structural relaxation, surface water content, and glass transformation temperature are identified as the major factors having an influence on the properties. A model connecting these features is suggested. A difference in the structure, hardness, and topography on the air and tin sides of float glass is also shown to exist. The contact damage behavior of the treated surfaces is shown to differ from those of untreated surfaces, for SOsb2-treated float glass, where the crack initiation characteristics indicate crack formation from the surface and the indenter tip, different than the expected anomalous deformation. This behavior resembles that of a silica glass deformation on the surface, which is in agreement with the other foundations in this study.

Tsunami Risk in the NE Atlantic: Pilot Study for Algarve Portugal and Applications for future TWS

NASA Astrophysics Data System (ADS)

Omira, R.; Baptista, M. A.; Catita, C.; Carrilho, F.; Matias, L.

2012-04-01

Tsunami risk assessment is an essential component of any Tsunami Early Warning System due to its significant contribution to the disaster reduction by providing valuable information that serve as basis for mitigation preparedness and strategies. Generally, risk assessment combines the outputs of the hazard and the vulnerability assessment for considered exposed elements. In the NE Atlantic region, the tsunami hazard is relatively well established through compilation of tsunami historical events, evaluation of tsunamigenic sources and impact computations for site-specific coastal areas. While, tsunami vulnerability remains poorly investigated in spite of some few studies that focused on limited coastal areas of the Gulf of Cadiz region. This work seeks to present a pilot study for tsunami risk assessment that covers about 170 km of coasts of Algarve region, south of Portugal. This area of high coastal occupation and touristic activities was strongly impacted by the 1755 tsunami event as reported in various historical documents. An approach based upon a combination of tsunami hazard and vulnerability is developed in order to take into account the dynamic aspect of tsunami risk in the region that depends on the variation of hazard and vulnerability of exposed elements from a coastal point to other. Hazard study is based upon the consideration of most credible earthquake scenarios and the derivation of hazard maps through hydrodynamic modeling of inundation and tsunami arrival time. The vulnerability assessment is performed by: i) the analysis of the occupation and the population density, ii) derivation of evacuation maps and safe shelters, and iii) the analysis of population response and evacuation times. Different risk levels ranging from "low" to "high" are assigned to the coats of the studied area. Variation of human tsunami risk between the high and low touristic seasons is also considered in this study and aims to produce different tsunami risk-related scenarios. Results are presented in terms of thematic maps and GIS layers highlighting information on inundation depths and limits, evacuation plans and safe shelters, tsunami vulnerability, evacuation times and tsunami risk levels. Results can be used for national and regional tsunami disaster management and planning. This work is funded by TRIDEC (Collaborative, Complex and Critical Decision-Support in Evolving Crises) FP7, EU project and by MAREMOTI (Mareograph and field tsunami observations, modeling and vulnerability studies for Northeast Atlantic and western Mediterranean) French project. Keywords: Tsunami, Algarve-Portugal, Evacuation, Vulnerability, Risk

Contribution of Anisotropy of Magnetic Susceptibility (AMS) to reconstruct flooding characteristics of a 4220 BP tsunami from a thick unconsolidated structureless deposit (Banda Aceh, Sumatra)

NASA Astrophysics Data System (ADS)

Wassmer, Patrick; Gomez, Christopher; Iskandasyah, T. Yan W. M.; Lavigne, Franck; Sartohadi, Junun

2015-07-01

One of the main concerns of deciphering tsunami sedimentary records along seashore is to link the emplaced layers with marine high energy events. Based on a combination of morphologic features, sedimentary figures, grain size characteristics, fossils content, microfossils assemblages, geochemical elements, heavy minerals presence; it is, in principle, possible to relate the sedimentary record to a tsunami event. However, experience shows that sometimes, in reason of a lack of any visible sedimentary features, it is hard to decide between a storm and a tsunami origin. To solve this issue, the authors have used the Anisotropy of Magnetic Susceptibility (AMS) to evidence the sediment fabric. The validity of the method for reconstructing flow direction has been proved when applied on sediments in the aftermath of a tsunami event, for which the behaviour was well documented (2004 IOT). We present herein an application of this method for a 56 cm thick paleo-deposit dated 4220 BP laying under the soil covered by the 2004 IOT, SE of Banda Aceh, North Sumatra. We analysed this homogenous deposit, lacking of any visible structure, using methods of classic sedimentology to confirm the occurrence of a high energy event. We then applied AMS technique that allowed the reconstruction of flow characteristics during sediment emplacement. We show that all the sequence was emplaced by uprush phases and that the local topography played a role on the re-orientation of a part of the uprush flow, creating strong reverse current. This particular behaviour was reported by eyewitnesses during the 2004 IOT event.

Physical modeling of long-wave run-up mitigation using submerged breakwaters

NASA Astrophysics Data System (ADS)

Lee, Yu-Ting; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

2016-04-01

Natural hazard due to tsunami inundation inland has been viewed as a crucial issue for coastal engineering community. The 2004 India Ocean tsunami and the 2011 Tohoku earthquake tsunami were caused by mega scale earthquakes that brought tremendous catastrophe in the disaster regions. It is thus of great importance to develop innovative approach to achieve the reduction and mitigation of tsunami hazards. In this study, new experiments have been carried out in a laboratory-scale to investigate the physical process of long-wave through submerged breakwaters built upon a mild slope. Solitary-wave is employed to represent the characteristic of long-wave with infinite wavelength and wave period. Our goal is twofold. First of all, through changing the positions of single breakwater and multiple breakwaters upon a mild slope, the optimal locations of breakwaters can be pointed out by means of maximum run-up reduction. Secondly, through using a state-of-the-art measuring technique Bubble Image Velocimetry, which features non-intrusive and image-based measurement, the wave kinematics in the highly aerated region due to solitary-wave shoaling, breaking and uprush can be quantitated. Therefore, the mitigation of long-wave due to the construction of submerged breakwaters built upon a mild slope can be evaluated not only for imaging run-up and run-down characteristics but also for measuring turbulent velocity fields due to breaking wave. Although we understand the most devastating tsunami hazards cannot be fully mitigated with impossibility, this study is to provide quantitated information on what kind of artificial coastal structure that can withstand which level of wave loads.

Tsunami Hazards - A National Threat

USGS Publications Warehouse

,

2006-01-01

In December 2004, when a tsunami killed more than 200,000 people in 11 countries around the Indian Ocean, the United States was reminded of its own tsunami risks. In fact, devastating tsunamis have struck North America before and are sure to strike again. Especially vulnerable are the five Pacific States--Hawaii, Alaska, Washington, Oregon, and California--and the U.S. Caribbean islands. In the wake of the Indian Ocean disaster, the United States is redoubling its efforts to assess the Nation's tsunami hazards, provide tsunami education, and improve its system for tsunami warning. The U.S. Geological Survey (USGS) is helping to meet these needs, in partnership with the National Oceanic and Atmospheric Administration (NOAA) and with coastal States and counties.

Seismically generated tsunamis.

PubMed

Arcas, Diego; Segur, Harvey

2012-04-13

People around the world know more about tsunamis than they did 10 years ago, primarily because of two events: a tsunami on 26 December 2004 that killed more than 200,000 people around the shores of the Indian Ocean; and an earthquake and tsunami off the coast of Japan on 11 March 2011 that killed nearly 15,000 more and triggered a nuclear accident, with consequences that are still unfolding. This paper has three objectives: (i) to summarize our current knowledge of the dynamics of tsunamis; (ii) to describe how that knowledge is now being used to forecast tsunamis; and (iii) to suggest some policy changes that might protect people better from the dangers of future tsunamis.

E A R T H - S C I E N C E S L I N K S

Science.gov Websites

TSUNAMI! NOAA TSUNAMI Project TSUNAMI Web Site TSUNAMIS in the circum-Pacific Ring of Fire The TSUNAMI DINOSAURS PLATE TECTONICS The Dinosaur Web Pages DINOSAURIA ON-LINE Fossils & Dinosaurs Earth Through opportunities in the earth sciences Geologic Time USGS Learning Web Geoscience Information Center National

Stand-alone tsunami alarm equipment

NASA Astrophysics Data System (ADS)

Katsumata, Akio; Hayashi, Yutaka; Miyaoka, Kazuki; Tsushima, Hiroaki; Baba, Toshitaka; Catalán, Patricio A.; Zelaya, Cecilia; Riquelme Vasquez, Felipe; Sanchez-Olavarria, Rodrigo; Barrientos, Sergio

2017-05-01

One of the quickest means of tsunami evacuation is transfer to higher ground soon after strong and long ground shaking. Ground shaking itself is a good initiator of the evacuation from disastrous tsunami. Longer period seismic waves are considered to be more correlated with the earthquake magnitude. We investigated the possible application of this to tsunami hazard alarm using single-site ground motion observation. Information from the mass media is sometimes unavailable due to power failure soon after a large earthquake. Even when an official alarm is available, multiple information sources of tsunami alert would help people become aware of the coming risk of a tsunami. Thus, a device that indicates risk of a tsunami without requiring other data would be helpful to those who should evacuate. Since the sensitivity of a low-cost MEMS (microelectromechanical systems) accelerometer is sufficient for this purpose, tsunami alarm equipment for home use may be easily realized. Amplitude of long-period (20 s cutoff) displacement was proposed as the threshold for the alarm based on empirical relationships among magnitude, tsunami height, hypocentral distance, and peak ground displacement of seismic waves. Application of this method to recent major earthquakes indicated that such equipment could effectively alert people to the possibility of tsunami.

Measuring and forecasting great tsunamis by GNSS-based vertical positioning of multiple ships

NASA Astrophysics Data System (ADS)

Inazu, D.; Waseda, T.; Hibiya, T.; Ohta, Y.

2016-12-01

Vertical ship positioning by the Global Navigation Satellite System (GNSS) was investigated for measuring and forecasting great tsunamis. We first examined existing GNSS vertical position data of a navigating vessel. The result indicated that by using the kinematic Precise Point Positioning (PPP) method, tsunamis greater than 10^-1 m can be detected from the vertical position of the ship. Based on Automatic Identification System (AIS) data, tens of cargo ships and tankers are regularly identified navigating over the Nankai Trough, southwest of Japan. We then assumed that a future Nankai Trough great earthquake tsunami will be observed by ships at locations based on AIS data. The tsunami forecast capability by these virtual offshore tsunami measurements was examined. A conventional Green's function based inversion was used to determine the initial tsunami height distribution. Tsunami forecast tests over the Nankai Trough were carried out using simulated tsunami data of the vertical positions of multiple cargo ships/tankers on a certain day, and of the currently operating observations by deep-sea pressure gauges and Global Positioning System (GPS) buoys. The forecast capability of ship-based tsunami height measurements alone was shown to be comparable to or better than that using the existing offshore observations.

GPS water level measurements for Indonesia's Tsunami Early Warning System

NASA Astrophysics Data System (ADS)

Schöne, T.; Pandoe, W.; Mudita, I.; Roemer, S.; Illigner, J.; Zech, C.; Galas, R.

2011-03-01

On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements. The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS) (Rudloff et al., 2009) combines GPS technology and ocean bottom pressure (OBP) measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information. The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

A global probabilistic tsunami hazard assessment from earthquake sources

USGS Publications Warehouse

Davies, Gareth; Griffin, Jonathan; Lovholt, Finn; Glimsdal, Sylfest; Harbitz, Carl; Thio, Hong Kie; Lorito, Stefano; Basili, Roberto; Selva, Jacopo; Geist, Eric L.; Baptista, Maria Ana

2017-01-01

Large tsunamis occur infrequently but have the capacity to cause enormous numbers of casualties, damage to the built environment and critical infrastructure, and economic losses. A sound understanding of tsunami hazard is required to underpin management of these risks, and while tsunami hazard assessments are typically conducted at regional or local scales, globally consistent assessments are required to support international disaster risk reduction efforts, and can serve as a reference for local and regional studies. This study presents a global-scale probabilistic tsunami hazard assessment (PTHA), extending previous global-scale assessments based largely on scenario analysis. Only earthquake sources are considered, as they represent about 80% of the recorded damaging tsunami events. Globally extensive estimates of tsunami run-up height are derived at various exceedance rates, and the associated uncertainties are quantified. Epistemic uncertainties in the exceedance rates of large earthquakes often lead to large uncertainties in tsunami run-up. Deviations between modelled tsunami run-up and event observations are quantified, and found to be larger than suggested in previous studies. Accounting for these deviations in PTHA is important, as it leads to a pronounced increase in predicted tsunami run-up for a given exceedance rate.

Tsunami Research Program | PEER Center

Science.gov Websites

including coastal bridges, and important public facilities (fire and police stations, hospitals, and schools ). Failure of critical coastal structures and lifelines likely lead to loss of life, delays in emergency

Warnings and reactions to the Tohoku tsunami in Hawaii

NASA Astrophysics Data System (ADS)

Houghton, B. F.; Gregg, C. E.

2012-12-01

The 2011 Tohoku tsunami was the first chance within the USA to document and interpret large-scale response and protective action behavior with regard to a large, destructive tsunami since 1964. The 2011 tsunami offered a unique, short-lived opportunity to transform our understanding of individual and collective behavior in the US in response to a well-publicized tsunami warning and, in particular, to look at the complex interplay of official information sources, informal warnings and information-seeking in communities with significant physical impact from the 2011 tsunami. This study is focused in Hawaii, which suffered significant ($30 M), but localized damage, from the 2011 Tohoku tsunami and underwent a full-scale tsunami evacuation. The survey contrasts three Hawaiian communities which either experienced significant tsunami damage (Kona) or little physical impact (Hilo, Honolulu). It also contrasts a long-established local community with experience of evacuation, destruction and loss of life in two tsunamis (Hilo) with a metropolitan population with a large visitor presence (Honolulu) that has not experienced a damaging tsunami in decades. Many factors such as personal perceptions of risk, beliefs, past exposure to the hazard, forecast uncertainty, trust in information sources, channels of transmission of information, the need for message confirmation, responsibilities, obligations, mobility, the ability to prepare, the availability of transportation and transport routes, and an acceptable evacuation center affected behavior. We provide new information on how people reacted to warnings and tsunamis, especially with regard to social integration of official warnings and social media. The results of this study will strengthen community resilience to tsunamis, working with emergency managers to integrate strengths and weaknesses of the public responses with official response plans.

Simulated tsunami inundation for a range of Cascadia megathrust earthquake scenarios at Bandon, Oregon, USA

USGS Publications Warehouse

Witter, Robert C.; Zhang, Yinglong J.; Wang, Kelin; Priest, George R.; Goldfinger, Chris; Stimely, Laura; English, John T.; Ferro, Paul A.

2013-01-01

Characterizations of tsunami hazards along the Cascadia subduction zone hinge on uncertainties in megathrust rupture models used for simulating tsunami inundation. To explore these uncertainties, we constructed 15 megathrust earthquake scenarios using rupture models that supply the initial conditions for tsunami simulations at Bandon, Oregon. Tsunami inundation varies with the amount and distribution of fault slip assigned to rupture models, including models where slip is partitioned to a splay fault in the accretionary wedge and models that vary the updip limit of slip on a buried fault. Constraints on fault slip come from onshore and offshore paleoseismological evidence. We rank each rupture model using a logic tree that evaluates a model’s consistency with geological and geophysical data. The scenarios provide inputs to a hydrodynamic model, SELFE, used to simulate tsunami generation, propagation, and inundation on unstructured grids with <5–15 m resolution in coastal areas. Tsunami simulations delineate the likelihood that Cascadia tsunamis will exceed mapped inundation lines. Maximum wave elevations at the shoreline varied from ∼4 m to 25 m for earthquakes with 9–44 m slip and Mw 8.7–9.2. Simulated tsunami inundation agrees with sparse deposits left by the A.D. 1700 and older tsunamis. Tsunami simulations for large (22–30 m slip) and medium (14–19 m slip) splay fault scenarios encompass 80%–95% of all inundation scenarios and provide reasonable guidelines for land-use planning and coastal development. The maximum tsunami inundation simulated for the greatest splay fault scenario (36–44 m slip) can help to guide development of local tsunami evacuation zones.

Lessons unlearned in Japan before 2011: Effects of the 2004 Indian Ocean tsunami on a nuclear plant in India

NASA Astrophysics Data System (ADS)

Sugimoto, M.

2015-12-01

The 2004 Indian Ocean tsunami killed around 220,000 people and startled the world. North of Chennai (Madras), the Indian plant nearly affected by tsunami in 2004. The local residents really did not get any warning in India. "On December 26, the Madras Atomic Power Station looked like a desolate place with no power, no phones, no water, no security arrangement and no hindrance whatsoever for outsiders to enter any part of the plant," said S.P. Udaykumar of SACCER. Nuclear issues hide behind such big tsunami damaged. Few media reported outside India. As for US, San Francisco Chronicle reported scientists had to rethink about nuclear power plants by the 2004 tsunami in 11th July 2005. Few tsunami scientsts did not pay attention to nucler power plants nearly affected by tsunami in US. On the other hand, US government noticed the Indian plant nearly affected in 2004. US Goverment supported nucler disaster management in several countries. As for Japan, Japanese goverment mainly concentrated reconstrucation in affected areas and tsunami early warning system. I worked in Japanese embassy in Jakarta Indonesia at that time. I did not receive the information about the Indian plant nearly affected by tsunami and US supported nucler safety to the other coutries. The 2011 Tohoku earthquake and tsunami damaged society and nuclear power stations. The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident resulted in the largest release of radioactive material since the 1986 Chernobyl accident. Why did not Japanese tsunami scientists learn from warning signs from the nuclear plant in India by the 2004 Indian Ocean tsunami to the 2011 Fukushima accident? I would like to clarify the reason few tsunami scientist notice this point in my presentation.

Modeling of Grain Size Distribution of Tsunami Sand Deposits in V-shaped Valley of Numanohama During the 2011 Tohoku Tsunami

NASA Astrophysics Data System (ADS)

Gusman, A. R.; Satake, K.; Goto, T.; Takahashi, T.

2016-12-01

Estimating tsunami amplitude from tsunami sand deposit has been a challenge. The grain size distribution of tsunami sand deposit may have correlation with tsunami inundation process, and further with its source characteristics. In order to test this hypothesis, we need a tsunami sediment transport model that can accurately estimate grain size distribution of tsunami deposit. Here, we built and validate a tsunami sediment transport model that can simulate grain size distribution. Our numerical model has three layers which are suspended load layer, active bed layer, and parent bed layer. The two bed layers contain information about the grain size distribution. This numerical model can handle a wide range of grain sizes from 0.063 (4 ϕ) to 5.657 mm (-2.5 ϕ). We apply the numerical model to simulate the sedimentation process during the 2011 Tohoku earthquake in Numanohama, Iwate prefecture, Japan. The grain size distributions at 15 sample points along a 900 m transect from the beach are used to validate the tsunami sediment transport model. The tsunami deposits are dominated by coarse sand with diameter of 0.5 - 1 mm and their thickness are up to 25 cm. Our tsunami model can well reproduce the observed tsunami run-ups that are ranged from 16 to 34 m along the steep valley in Numanohama. The shapes of the simulated grain size distributions at many sample points located within 300 m from the shoreline are similar to the observations. The differences between observed and simulated peak of grain size distributions are less than 1 ϕ. Our result also shows that the simulated sand thickness distribution along the transect is consistent with the observation.

Near Source 2007 Peru Tsunami Runup Observations and Modeling

NASA Astrophysics Data System (ADS)

Borrero, J. C.; Fritz, H. M.; Kalligeris, N.; Broncano, P.; Ortega, E.

2008-12-01

On 15 August 2007 an earthquake with moment magnitude (Mw) of 8.0 centered off the coast of central Peru, generated a tsunami with locally focused runup heights of up to 10 m. A reconnaissance team was deployed two weeks after the event and investigated the tsunami effects at 51 sites. Three tsunami fatalities were reported south of the Paracas Peninsula in a sparsely populated desert area where the largest tsunami runup heights and massive inundation distances up to 2 km were measured. Numerical modeling of the earthquake source and tsunami suggest that a region of high slip near the coastline was primarily responsible for the extreme runup heights. The town of Pisco was spared by the Paracas Peninsula, which blocked tsunami waves from propagating northward from the high slip region. As with all near field tsunamis, the waves struck within minutes of the massive ground shaking. Spontaneous evacuations coordinated by the Peruvian Coast Guard minimized the fatalities and illustrate the importance of community-based education and awareness programs. The residents of the fishing village Lagunilla were unaware of the tsunami hazard after an earthquake and did not evacuate, which resulted in 3 fatalities. Despite the relatively benign tsunami effects at Pisco from this event, the tsunami hazard for this city (and its liquefied natural gas terminal) cannot be underestimated. Between 1687 and 1868, the city of Pisco was destroyed 4 times by tsunami waves. Since then, two events (1974 and 2007) have resulted in partial inundation and moderate damage. The fact that potentially devastating tsunami runup heights were observed immediately south of the peninsula only serves to underscore this point.

Role of State Tsunami Geoscientists during Emergency Response Activities: Example from the State of California (USA) during September 29, 2009, Samoa Tsunami Event

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Dengler, L. A.; Goltz, J. D.; Legg, M.; Miller, K. M.; Parrish, J. G.; Whitmore, P.

2009-12-01

California tsunami geoscientists work closely with federal, state and local government emergency managers to help prepare coastal communities for potential impacts from a tsunami before, during, and after an event. For teletsunamis, as scientific information (forecast model wave heights, first-wave arrival times, etc.) from NOAA’s West Coast and Alaska’s Tsunami Warning Center is made available, state-level emergency managers must help convey this information in a concise and comprehendible manner to local officials who ultimately determine the appropriate response activities for their jurisdictions. During the Samoa Tsunami Advisory for California on September 29, 2009, geoscientists from the California Geological Survey and Humboldt State University assisted the California Emergency Management Agency in this information transfer by providing technical assistance during teleconference meetings with NOAA and other state and local emergency managers prior to the arrival of the tsunami. State geoscientists gathered additional background information on anticipated tidal conditions and wave heights for areas not covered by NOAA’s forecast models. The participation of the state geoscientists in the emergency response process resulted in clarifying which regions were potentially at-risk, as well as those having a low risk from the tsunami. Future tsunami response activities for state geoscientists include: 1) working closely with NOAA to simplify their tsunami alert messaging and expand their forecast modeling coverage, 2) creation of “playbooks” containing information from existing tsunami scenarios for local emergency managers to reference during an event, and 3) development of a state-level information “clearinghouse” and pre-tsunami field response team to assist local officials as well as observe and report tsunami effects.

Motion performance and mooring system of a floating offshore wind turbine

NASA Astrophysics Data System (ADS)

Zhao, Jing; Zhang, Liang; Wu, Haitao

2012-09-01

The development of offshore wind farms was originally carried out in shallow water areas with fixed (seabed mounted) structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine (FOWT) system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.

33 CFR 165.838 - Regulated Navigation Area; Gulf Intracoastal Waterway, Inner Harbor Navigation Canal, New Orleans...

Code of Federal Regulations, 2014 CFR

2014-07-01

... before closure of the navigational structures, all floating vessels must depart the RNA except as follows... Harbor Navigation Canal, New Orleans, LA. (a) Location. The following is a regulated navigation area (RNA... West of Harvey Locks (WHL) (b) Definitions. As used in this section: (1) Breakaway means a floating...

On the nature of control algorithms for free-floating space manipulators

NASA Technical Reports Server (NTRS)

Papadopoulos, Evangelos; Dubowsky, Steven

1991-01-01

It is suggested that nearly any control algorithm that can be used for fixed-based manipulators also can be employed in the control of free-floating space manipulator systems, with the additional conditions of estimating or measuring a spacecraft's orientation and of avoiding dynamic singularities. This result is based on the structural similarities between the kinematic and dynamic equations for the same manipulator but with a fixed base. Barycenters are used to formulate the kinematic and dynamic equations of free-floating space manipulators. A control algorithm for a space manipulator system is designed to demonstrate the value of the analysis.

The ASTARTE Paleotsunami and Mass Transport Deposits data bases - web-based references for tsunami and submarine landslide research around Europe

NASA Astrophysics Data System (ADS)

De Martini, Paolo Marco; Patera, Antonio; Orefice, Simone; Paris, Raphael; Völker, David; Lastras, Galderic; Terrinha, Pedro; Noiva, João; Smedile, Alessandra; Pantosti, Daniela; Hunt, James; Gutscher, Marc-Andre; Migeon, Sébastien; Papadopoulos, Gerassimos; Triantafyllou, Ioanna; Yalciner, Ahmet C.

2017-04-01

EU project ASTARTE aims at developing a higher level of tsunami hazard assessment in the North East Atlantic, Mediterranean and Connected seas (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the description of past tsunamigenic events, the identification and characterization of tsunami sources, the calculation of the impact of such events, and the development of adequate resilience and risks mitigation strategies (www.astarte.eu). Within ASTARTE two web-based data bases on Paleotsunami and Mass Transport Deposits in the NEAM areas were created with the purpose to be the future information repositories for tsunami research in Europe.The aim is to integrate every existing official scientific reports and peer reviewed papers on these topics and update on new entries every 6-12 months, hosting information and detailed data, that are crucial e.g for tsunami modeling. A relational database managed by ArcGIS for Desktop 10.x software has been implemented. One of the final goals of the project is the public sharing of the archived datasets through a web-based map service that will allow visualizing, querying, analyzing, and interpreting all datasets. The interactive map service will be hosted by ArcGIS Online and will deploy the cloud capabilities of the portal. Any interested users will be able to access the online GIS resources through any Internet browser or specific apps that run on desktop machines, smartphones, or tablets and will be able to use the analytical tools, key tasks, and workflows of the service.We will present the data bases structure and topics as well as their ArcGIS Online version. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe).

The application of Ground Penetrating Radar analysis to investigate the impact and recovery of coastal dunes and the recurrence interval of overwash events

NASA Astrophysics Data System (ADS)

Switzer, A.; Gouramanis, C.; Bristow, C. S.; Jankaew, K.; Rubin, C. M.; Pham, D. T.; Ildefonso, S. R.; Lee, Y. S.

2013-12-01

The common techniques for investigating the impact, recovery and recurrence interval in coastal systems are point source augering or pitting and/or excavations. These techniques are time and cost intensive. Ground Penetrating Radar (GPR) presents a rapid, non-invasive, spatially-continuous technique for identifying subsurface stratigraphy. Although GPR facies are not diagnostic of a particular sedimentary characteristic, when combined with satellite imagery, they provide an avenue for reconstructing the impact and the post event recovery, or to help constrain the spatial extent of sandy deposits in the subsurface. Here, we present results from two GPR survey campaigns at Phra Thong Island, Thailand. The first campaign targeted the large scale recovery of the coast following the 2004 Indian ocean tsunami using 200 MHz antennae and the second campaign focused on a thin-bed approach aimed at imaging thin (<15 cm) sandy tsunami deposits and their associated structures using high-frequency 500 and 1000 MHz GPR antennae complemented by auger cores. The tsunami impact and recovery was reconciled by three 100 MHz GPR profiles and quasi-yearly satellite imagery. The GPR revealed the depth and extent of tsunami scour along with the sedimentary history of post tsunami coastal aggradation and recovery. The second GPR campaign captured several distinct palaeotsunami deposits as discreet thin sand layers preserved within a swale. The base of the swale and the contacts between the sandy and muddy layers are clearly imaged, although these reflectors are less consistent across the profile, suggesting that the contacts between thin sand and mud units can be accurately imaged provided the units are thicker than ca. 10cm. Our investigations show that GPR can be used to rapidly and non-invasively assess post event recovery and to image sandy washover events in muddy swales that are the result of tsunamis or storms.

Monitoring Coastal Change after the Tsunami in Thailand

NASA Astrophysics Data System (ADS)

Pantanahiran, W.

2014-03-01

The tsunami on December 26, 2004 caused widespread devastation along the coast of Thailand, especially in Ban Nam Khem, Phang Nga province. This disaster claimed more than 941 lives, with 502 other people missing when the storm surge caught the residents of this area. The coastal geomorphology was impacted by this disaster. The objectives of the research were to study the effect of the tsunami on coastal change and the recovery of coastal areas. Six time-series datasets of aerial photographs and satellite images from 2002, 2004, 2005, 2006, 2009, and 2010 were compared using the Geographic Information System (GIS). The results showed the effect of the tsunami on the buildings in the area. Fifty-eight point sixty-three percent of the buildings in the urban area were destroyed by the tsunami and constructions was raised to 103.60% and 197.12% between 2004 and 2010, thus indicating the recovery of the local community. Geomorphological change in Ko Kho Khao (the island) was found after the tsunami disaster, including coastal erosion and coastal deposition. The balance of nature played a major role in controlling the erosion and deposition. The coastal deposits were the highest in 2005; however, deposition was not found in 2004. The erosion rate from 2002-2003 was the highest (48.10 meter per year) and higher than 2003-2004 (39.03 meters per year), 2004-2009 (15.64 meters per year) and 2009-2010 (29.49 meters per year). The coastal area was more severe eroded than the estuary area, and severe coastal erosion caused the loss of coastal area, approximately 0.28 ha. Severe coastal erosion has been repeatedly found since 2005 in the lower part of the area, and hard structures such as concrete seawalls might have been affected by coastal erosion. In addition, extrapolation of coastal erosion at the rate of 30 meters per year showed that the lower part of Ko Kho Khao should disappear in 2015.

Tsunami Evidence in South Coast Java, Case Study: Tsunami Deposit along South Coast of Cilacap

NASA Astrophysics Data System (ADS)

Rizal, Yan; Aswan; Zaim, Yahdi; Dwijo Santoso, Wahyu; Rochim, Nur; Daryono; Dewi Anugrah, Suci; Wijayanto; Gunawan, Indra; Yatimantoro, Tatok; Hidayanti; Herdiyani Rahayu, Resti; Priyobudi

2017-06-01

Cilacap Area is situated in coastal area of Southern Java and directly affected by tsunami hazard in 2006. This event was triggered by active subduction in Java Trench which active since long time ago. To detect tsunami and active tectonic in Southern Java, paleo-tsunami study is performed which is targeted paleo-tsunami deposit older than fifty years ago. During 2011 - 2016, 16 locations which suspected as paleo-tsunami location were visited and the test-pits were performed to obtain characteristic and stratigraphy of paleo-tsunami layers. Paleo-tsunami layer was identified by the presence of light-sand in the upper part of paleo-soil, liquefaction fine grain sandstone, and many rip-up clast of mudstone. The systematic samples were taken and analysis (micro-fauna, grainsize and dating analysis). Micro-fauna result shows that paleo-tsunami layer consist of benthonic foraminifera assemblages from different bathymetry and mixing in one layer. Moreover, grainsize shows random grain distribution which characterized as turbulence and strong wave deposit. Paleo-tsunami layers in Cilacap area are correlated using paleo-soil as marker. There are three paleo-tsunami layers and the distribution can be identified as PS-A, PS-B and PS-C. The samples which were taken in Glempang Pasir layer are being dated using Pb - Zn (Lead-Zinc) method. The result of Pb - Zn (Lead-Zinc) dating shows that PS-A was deposited in 139 years ago, PS-B in 21 years ago, and PS C in 10 years ago. This result indicates that PS -1 occurred in 1883 earthquake activity while PS B formed in 1982 earthquake and PS-C was formed by 2006 earthquake. For ongoing research, the older paleo-tsunami layers were determined in the Gua Nagaraja, close to Selok location and 6 layers of Paleo-tsunami suspect found which shown a similar characteristic with the layers from another location. The three layers deeper approximately have an older age than another location in Cilacap.

The Dependency of Probabilistic Tsunami Hazard Assessment on Magnitude Limits of Seismic Sources in the South China Sea and Adjoining Basins

NASA Astrophysics Data System (ADS)

Li, Hongwei; Yuan, Ye; Xu, Zhiguo; Wang, Zongchen; Wang, Juncheng; Wang, Peitao; Gao, Yi; Hou, Jingming; Shan, Di

2017-06-01

The South China Sea (SCS) and its adjacent small basins including Sulu Sea and Celebes Sea are commonly identified as tsunami-prone region by its historical records on seismicity and tsunamis. However, quantification of tsunami hazard in the SCS region remained an intractable issue due to highly complex tectonic setting and multiple seismic sources within and surrounding this area. Probabilistic Tsunami Hazard Assessment (PTHA) is performed in the present study to evaluate tsunami hazard in the SCS region based on a brief review on seismological and tsunami records. 5 regional and local potential tsunami sources are tentatively identified, and earthquake catalogs are generated using Monte Carlo simulation following the Tapered Gutenberg-Richter relationship for each zone. Considering a lack of consensus on magnitude upper bound on each seismic source, as well as its critical role in PTHA, the major concern of the present study is to define the upper and lower limits of tsunami hazard in the SCS region comprehensively by adopting different corner magnitudes that could be derived by multiple principles and approaches, including TGR regression of historical catalog, fault-length scaling, tectonic and seismic moment balance, and repetition of historical largest event. The results show that tsunami hazard in the SCS and adjoining basins is subject to large variations when adopting different corner magnitudes, with the upper bounds 2-6 times of the lower. The probabilistic tsunami hazard maps for specified return periods reveal much higher threat from Cotabato Trench and Sulawesi Trench in the Celebes Sea, whereas tsunami hazard received by the coasts of the SCS and Sulu Sea is relatively moderate, yet non-negligible. By combining empirical method with numerical study of historical tsunami events, the present PTHA results are tentatively validated. The correspondence lends confidence to our study. Considering the proximity of major sources to population-laden cities around the SCS region, the tsunami hazard and risk should be further highlighted in the future.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-04-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

Does Morphological Adjustment During Tsunami Inundation Increase Levels of Hazard?

NASA Astrophysics Data System (ADS)

Tehranirad, B.; Kirby, J. T., Jr.; Shi, F.; Grilli, S. T.

2016-12-01

Previous inundation mapping results for the US East Coast have shown that barrier islands would be among the most impacted areas during a possible tsunami. Many of these barriers are home to large population centers such as Atlantic City, NJ and Ocean City, MD. A tsunami can significantly change coastal morphology. Post-tsunami surveys have shown that large amounts of sediment can be moved in bays and estuaries by tsunami action, especially over coastal dunes. During tsunami inundation, large amounts of sediment have been eroded from sandy coasts and deposited further onshore. In some cases, sand dunes have been completely eroded by a tsunami, with the eroded sediment being deposited either onshore behind the dunes, or offshore during the rundown process. Given the potential for tsunamis to change coastal morphology, it is necessary to consider whether barrier island morphology change during inundation, if accounted for, would increase the assessment of tsunami hazard identified in the development of inundation and evacuation maps. In this presentation, we will show the results of our recent study on the morphological response of barrier islands during possible tsunamis that threaten the US East Coast. For this purpose, we have coupled the Boussinesq model FUNWAVE-TVD with a depth-averaged advection-diffusion sediment transport model and a morphology module to capture bed evolution under tsunami conditions. The model is verified in comparison to laboratory observations and to observed erosion/deposition patterns in Crescent City, CA harbor during the 2011 Tohoku-oki tsunami. We then use the model to study the effect of morphology change on predicted inundation limits for two barrier islands: the undeveloped Assateague Island, and the developed Ocean City, MD, using the tsunami sources utilized in previous hazard analysis. Our results suggest that significant bathymetric changes could be expected on a barrier island during tsunami inundation, leading to large increases in inundation areas for some of the events, particularly for smaller events where inundation without progressive dune breaching is minor.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-03-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

Structural control on the Tohoku earthquake rupture process investigated by 3D FEM, tsunami and geodetic data

PubMed Central

Romano, F.; Trasatti, E.; Lorito, S.; Piromallo, C.; Piatanesi, A.; Ito, Y.; Zhao, D.; Hirata, K.; Lanucara, P.; Cocco, M.

2014-01-01

The 2011 Tohoku earthquake (Mw = 9.1) highlighted previously unobserved features for megathrust events, such as the large slip in a relatively limited area and the shallow rupture propagation. We use a Finite Element Model (FEM), taking into account the 3D geometrical and structural complexities up to the trench zone, and perform a joint inversion of tsunami and geodetic data to retrieve the earthquake slip distribution. We obtain a close spatial correlation between the main deep slip patch and the local seismic velocity anomalies, and large shallow slip extending also to the North coherently with a seismically observed low-frequency radiation. These observations suggest that the friction controlled the rupture, initially confining the deeper rupture and then driving its propagation up to the trench, where it spreads laterally. These findings are relevant to earthquake and tsunami hazard assessment because they may help to detect regions likely prone to rupture along the megathrust, and to constrain the probability of high slip near the trench. Our estimate of ~40 m slip value around the JFAST (Japan Trench Fast Drilling Project) drilling zone contributes to constrain the dynamic shear stress and friction coefficient of the fault obtained by temperature measurements to ~0.68 MPa and ~0.10, respectively. PMID:25005351

Upper-plate splay fault earthquakes along the Arakan subduction belt recorded by uplifted coral microatolls on northern Ramree Island, western Myanmar (Burma)

NASA Astrophysics Data System (ADS)

Shyu, J. Bruce H.; Wang, Chung-Che; Wang, Yu; Shen, Chuan-Chou; Chiang, Hong-Wei; Liu, Sze-Chieh; Min, Soe; Aung, Lin Thu; Than, Oo; Tun, Soe Thura

2018-02-01

Upper-plate structures that splay out from the megathrusts are common features along major convergent plate boundaries. However, their earthquake and tsunami hazard potentials have not yet received significant attention. In this study, we identified at least one earthquake event that may have been produced by an upper-plate splay fault offshore western Myanmar, based on U-Th ages of uplifted coral microatolls. This event is likely an earthquake that was documented historically in C.E. 1848, with an estimated magnitude between 6.8 and 7.2 based on regional structural characteristics. Such magnitude is consistent with the observed co-seismic uplift amount of ∼0.5 m. Although these events are smaller in magnitude than events produced by megathrusts, they may produce higher earthquake and tsunami hazards for local coastal communities due to their proximity. Our results also indicate that earthquake events with co-seismic uplift along the coast may not necessarily produce a flight of marine terraces. Therefore, using only records of uplifted marine terraces as megathrust earthquake proxies may overlook the importance of upper-plate splay fault ruptures, and underestimate the overall earthquake frequency for future seismic and tsunami hazards along major subduction zones of the world.

Structural control on the Tohoku earthquake rupture process investigated by 3D FEM, tsunami and geodetic data.

PubMed

Romano, F; Trasatti, E; Lorito, S; Piromallo, C; Piatanesi, A; Ito, Y; Zhao, D; Hirata, K; Lanucara, P; Cocco, M

2014-07-09

The 2011 Tohoku earthquake (Mw = 9.1) highlighted previously unobserved features for megathrust events, such as the large slip in a relatively limited area and the shallow rupture propagation. We use a Finite Element Model (FEM), taking into account the 3D geometrical and structural complexities up to the trench zone, and perform a joint inversion of tsunami and geodetic data to retrieve the earthquake slip distribution. We obtain a close spatial correlation between the main deep slip patch and the local seismic velocity anomalies, and large shallow slip extending also to the North coherently with a seismically observed low-frequency radiation. These observations suggest that the friction controlled the rupture, initially confining the deeper rupture and then driving its propagation up to the trench, where it spreads laterally. These findings are relevant to earthquake and tsunami hazard assessment because they may help to detect regions likely prone to rupture along the megathrust, and to constrain the probability of high slip near the trench. Our estimate of ~40 m slip value around the JFAST (Japan Trench Fast Drilling Project) drilling zone contributes to constrain the dynamic shear stress and friction coefficient of the fault obtained by temperature measurements to ~0.68 MPa and ~0.10, respectively.

Are inundation limit and maximum extent of sand useful for differentiating tsunamis and storms? An example from sediment transport simulations on the Sendai Plain, Japan

NASA Astrophysics Data System (ADS)

Watanabe, Masashi; Goto, Kazuhisa; Bricker, Jeremy D.; Imamura, Fumihiko

2018-02-01

We examined the quantitative difference in the distribution of tsunami and storm deposits based on numerical simulations of inundation and sediment transport due to tsunami and storm events on the Sendai Plain, Japan. The calculated distance from the shoreline inundated by the 2011 Tohoku-oki tsunami was smaller than that inundated by storm surges from hypothetical typhoon events. Previous studies have assumed that deposits observed farther inland than the possible inundation limit of storm waves and storm surge were tsunami deposits. However, confirming only the extent of inundation is insufficient to distinguish tsunami and storm deposits, because the inundation limit of storm surges may be farther inland than that of tsunamis in the case of gently sloping coastal topography such as on the Sendai Plain. In other locations, where coastal topography is steep, the maximum inland inundation extent of storm surges may be only several hundred meters, so marine-sourced deposits that are distributed several km inland can be identified as tsunami deposits by default. Over both gentle and steep slopes, another difference between tsunami and storm deposits is the total volume deposited, as flow speed over land during a tsunami is faster than during a storm surge. Therefore, the total deposit volume could also be a useful proxy to differentiate tsunami and storm deposits.

Impacts of tides on tsunami propagation due to potential Nankai Trough earthquakes in the Seto Inland Sea, Japan

NASA Astrophysics Data System (ADS)

Lee, Han Soo; Shimoyama, Tomohisa; Popinet, Stéphane

2015-10-01

The impacts of tides on extreme tsunami propagation due to potential Nankai Trough earthquakes in the Seto Inland Sea (SIS), Japan, are investigated through numerical experiments. Tsunami experiments are conducted based on five scenarios that consider tides at four different phases, such as flood, high, ebb, and low tides. The probes that were selected arbitrarily in the Bungo and Kii Channels show less significant effects of tides on tsunami heights and the arrival times of the first waves than those that experience large tidal ranges in inner basins and bays of the SIS. For instance, the maximum tsunami height and the arrival time at Toyomaesi differ by more than 0.5 m and nearly 1 h, respectively, depending on the tidal phase. The uncertainties defined in terms of calculated maximum tsunami heights due to tides illustrate that the calculated maximum tsunami heights in the inner SIS with standing tides have much larger uncertainties than those of two channels with propagating tides. Particularly in Harima Nada, the uncertainties due to the impacts of tides are greater than 50% of the tsunami heights without tidal interaction. The results recommend simulate tsunamis together with tides in shallow water environments to reduce the uncertainties involved with tsunami modeling and predictions for tsunami hazards preparedness. This article was corrected on 26 OCT 2015. See the end of the full text for details.

When is a Tsunami a Mega-Tsunami?

NASA Astrophysics Data System (ADS)

Chague-Goff, C.; Goff, J. R.; Terry, J. P.; Goto, K.

2014-12-01

The 2004 Indian Ocean Tsunami is commonly called a mega-tsunami, and this attribute has also been linked to the 2011 Tohoku-oki tsunami. However, since this term was first coined in the early 1990's there have been very few attempts to define it. As such it has been applied in a rather arbitrary fashion to a number of tsunami characteristics, such as wave height or amplitude at both the source and at distant locations, run-up height, geographical extent and impact. The first use of the term is related to a tsunami generated by a large bolide impact and indeed it seems entirely appropriate that the term should be used for such rare events on geological timescales. However, probably as a result of media-driven hyperbole, scientists have used this term at least twice in the last decade, which is hardly a significant portion of the geological timescale. It therefore seems reasonable to suggest that these recent unexpectedly large events do not fall in the category of mega-tsunami but into a category of exceptional events within historical experience and local perspective. The use of the term mega-tsunami over the past 14 years is discussed and a definition is provided that marks the relative uniqueness of these events and a new term, appropriately Japanese in origin, namely that of souteigai-tsunami, is proposed. Examples of these tsunamis will be provided.

WindWaveFloat (WWF): Final Scientific Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alla Weinstein; Roddier, Dominique; Banister, Kevin

2012-03-30

Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided thatmore » the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.« less

Far-Field Tsunami Hazard Assessment Along the Pacific Coast of Mexico by Historical Records and Numerical Simulation

NASA Astrophysics Data System (ADS)

Ortiz-Huerta, Laura G.; Ortiz, Modesto; García-Gastélum, Alejandro

2018-03-01

Historical records of the Chile (22 May 1960), Alaska (27 March 1964), and Tohoku (11 March 2011) tsunamis recorded along the Pacific Coast of Mexico are used to investigate the goodness of far-field tsunami modeling using a focal mechanism consisting in a uniform slip distribution on large thrust faults around the Pacific Ocean. The Tohoku 2011 tsunami records recorded by Deep ocean Assessment and Reporting of Tsunami (DART) stations, and at coastal tide stations, were used to validate transoceanic tsunami models applicable to the harbors of Ensenada, Manzanillo, and Acapulco on the coast of Mexico. The amplitude resulting from synthetic tsunamis originated by M w 9.3 earthquakes around the Pacific varies from 1 to 2.5 m, depending on the tsunami origin region and on the directivity due to fault orientation and waveform modification by prominent features of sea bottom relief.

Far-Field Tsunami Hazard Assessment Along the Pacific Coast of Mexico by Historical Records and Numerical Simulation

NASA Astrophysics Data System (ADS)

Ortiz-Huerta, Laura G.; Ortiz, Modesto; García-Gastélum, Alejandro

2018-04-01

Historical records of the Chile (22 May 1960), Alaska (27 March 1964), and Tohoku (11 March 2011) tsunamis recorded along the Pacific Coast of Mexico are used to investigate the goodness of far-field tsunami modeling using a focal mechanism consisting in a uniform slip distribution on large thrust faults around the Pacific Ocean. The Tohoku 2011 tsunami records recorded by Deep ocean Assessment and Reporting of Tsunami (DART) stations, and at coastal tide stations, were used to validate transoceanic tsunami models applicable to the harbors of Ensenada, Manzanillo, and Acapulco on the coast of Mexico. The amplitude resulting from synthetic tsunamis originated by M w 9.3 earthquakes around the Pacific varies from 1 to 2.5 m, depending on the tsunami origin region and on the directivity due to fault orientation and waveform modification by prominent features of sea bottom relief.

A possible space-based tsunami early warning system using observations of the tsunami ionospheric hole.

PubMed

Kamogawa, Masashi; Orihara, Yoshiaki; Tsurudome, Chiaki; Tomida, Yuto; Kanaya, Tatsuya; Ikeda, Daiki; Gusman, Aditya Riadi; Kakinami, Yoshihiro; Liu, Jann-Yenq; Toyoda, Atsushi

2016-12-01

Ionospheric plasma disturbances after a large tsunami can be detected by measurement of the total electron content (TEC) between a Global Positioning System (GPS) satellite and its ground-based receivers. TEC depression lasting for a few minutes to tens of minutes termed as tsunami ionospheric hole (TIH) is formed above the tsunami source area. Here we describe the quantitative relationship between initial tsunami height and the TEC depression rate caused by a TIH from seven tsunamigenic earthquakes in Japan and Chile. We found that the percentage of TEC depression and initial tsunami height are correlated and the largest TEC depressions appear 10 to 20 minutes after the main shocks. Our findings imply that Ionospheric TEC measurement using the existing ground receiver networks could be used in an early warning system for near-field tsunamis that take more than 20 minutes to arrive in coastal areas.

On the characteristics of landslide tsunamis

PubMed Central

Løvholt, F.; Pedersen, G.; Harbitz, C. B.; Glimsdal, S.; Kim, J.

2015-01-01

This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation. PMID:26392615

On the characteristics of landslide tsunamis.

PubMed

Løvholt, F; Pedersen, G; Harbitz, C B; Glimsdal, S; Kim, J

2015-10-28

This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation. © 2015 The Authors.

A possible space-based tsunami early warning system using observations of the tsunami ionospheric hole

PubMed Central

Kamogawa, Masashi; Orihara, Yoshiaki; Tsurudome, Chiaki; Tomida, Yuto; Kanaya, Tatsuya; Ikeda, Daiki; Gusman, Aditya Riadi; Kakinami, Yoshihiro; Liu, Jann-Yenq; Toyoda, Atsushi

2016-01-01

Ionospheric plasma disturbances after a large tsunami can be detected by measurement of the total electron content (TEC) between a Global Positioning System (GPS) satellite and its ground-based receivers. TEC depression lasting for a few minutes to tens of minutes termed as tsunami ionospheric hole (TIH) is formed above the tsunami source area. Here we describe the quantitative relationship between initial tsunami height and the TEC depression rate caused by a TIH from seven tsunamigenic earthquakes in Japan and Chile. We found that the percentage of TEC depression and initial tsunami height are correlated and the largest TEC depressions appear 10 to 20 minutes after the main shocks. Our findings imply that Ionospheric TEC measurement using the existing ground receiver networks could be used in an early warning system for near-field tsunamis that take more than 20 minutes to arrive in coastal areas. PMID:27905487

Observations and Modeling of the August 27, 2012 Earthquake and Tsunami affecting El Salvador and Nicaragua

NASA Astrophysics Data System (ADS)

Borrero, Jose C.; Kalligeris, Nikos; Lynett, Patrick J.; Fritz, Hermann M.; Newman, Andrew V.; Convers, Jaime A.

2014-12-01

On 27 August 2012 (04:37 UTC, 26 August 10:37 p.m. local time) a magnitude M w = 7.3 earthquake occurred off the coast of El Salvador and generated surprisingly large local tsunami. Following the event, local and international tsunami teams surveyed the tsunami effects in El Salvador and northern Nicaragua. The tsunami reached a maximum height of ~6 m with inundation of up to 340 m inland along a 25 km section of coastline in eastern El Salvador. Less severe inundation was reported in northern Nicaragua. In the far-field, the tsunami was recorded by a DART buoy and tide gauges in several locations of the eastern Pacific Ocean but did not cause any damage. The field measurements and recordings are compared to numerical modeling results using initial conditions of tsunami generation based on finite-fault earthquake and tsunami inversions and a uniform slip model.

The Pacific Tsunami Warning Center's Response to the Tohoku Earthquake and Tsunami

NASA Astrophysics Data System (ADS)

Weinstein, S. A.; Becker, N. C.; Shiro, B.; Koyanagi, K. K.; Sardina, V.; Walsh, D.; Wang, D.; McCreery, C. S.; Fryer, G. J.; Cessaro, R. K.; Hirshorn, B. F.; Hsu, V.

2011-12-01

The largest Pacific basin earthquake in 47 years, and also the largest magnitude earthquake since the Sumatra 2004 earthquake, struck off of the east coast of the Tohoku region of Honshu, Japan at 5:46 UTC on 11 March 2011. The Tohoku earthquake (Mw 9.0) generated a massive tsunami with runups of up to 40m along the Tohoku coast. The tsunami waves crossed the Pacific Ocean causing significant damage as far away as Hawaii, California, and Chile, thereby becoming the largest, most destructive tsunami in the Pacific Basin since 1960. Triggers on the seismic stations at Erimo, Hokkaido (ERM) and Matsushiro, Honshu (MAJO), alerted Pacific Tsunami Warning Center (PTWC) scientists 90 seconds after the earthquake began. Four minutes after its origin, and about one minute after the earthquake's rupture ended, PTWC issued an observatory message reporting a preliminary magnitude of 7.5. Eight minutes after origin time, the Japan Meteorological Agency (JMA) issued its first international tsunami message in its capacity as the Northwest Pacific Tsunami Advisory Center. In accordance with international tsunami warning system protocols, PTWC then followed with its first international tsunami warning message using JMA's earthquake parameters, including an Mw of 7.8. Additional Mwp, mantle wave, and W-phase magnitude estimations based on the analysis of later-arriving seismic data at PTWC revealed that the earthquake magnitude reached at least 8.8, and that a destructive tsunami would likely be crossing the Pacific Ocean. The earthquake damaged the nearest coastal sea-level station located 90 km from the epicenter in Ofunato, Japan. The NOAA DART sensor situated 600 km off the coast of Sendai, Japan, at a depth of 5.6 km recorded a tsunami wave amplitude of nearly two meters, making it by far the largest tsunami wave ever recorded by a DART sensor. Thirty minutes later, a coastal sea-level station at Hanasaki, Japan, 600 km from the epicenter, recorded a tsunami wave amplitude of nearly three meters. The evacuation of Hawaii's coastlines commenced at 7:31 UTC. Concurrent with this tsunami event, a widely-felt Mw 4.6 earthquake occurred beneath the island of Hawai`i at 8:58 UTC. PTWC responded within three minutes of origin time with a Tsunami Information Statement stating that the Hawaii earthquake would not generate a tsunami. After issuing 27 international tsunami bulletins to Pacific basin countries, and 16 messages to the State of Hawaii during a period of 25 hours after the event began, PTWC concluded its role during the Tohoku tsunami event with the issuance of the corresponding warning cancellation message at 6:36 UTC on 12 March 2011. During the following weeks, however, the PTWC would continue to respond to dozens of aftershocks related to the earthquake. We will present a complete timeline of PTWC's activities, both domestic and international, during the Tohoku tsunami event. We will also illustrate the immense number of website hits, phone calls, and media requests that flooded PTWC during the course of the event, as well as the growing role social media plays in communicating tsunami hazard information to the public.

How effective were mangroves as a defence against the recent tsunami?

PubMed

Dahdouh-Guebas, F; Jayatissa, L P; Di Nitto, D; Bosire, J O; Lo Seen, D; Koedam, N

2005-06-21

Whether or not mangroves function as buffers against tsunamis is the subject of in-depth research, the importance of which has been neglected or underestimated before the recent killer tsunami struck. Our preliminary post-tsunami surveys of Sri Lankan mangrove sites with different degrees of degradation indicate that human activity exacerbated the damage inflicted on the coastal zone by the tsunami.

Ocean-bottom pressure changes above a fault area for tsunami excitation and propagation observed by a submarine dense network

NASA Astrophysics Data System (ADS)

Yomogida, K.; Saito, T.

2017-12-01

Conventional tsunami excitation and propagation have been formulated by incompressible fluid with velocity components. This approach is valid in most cases because we usually analyze tunamis as "long gravity waves" excited by submarine earthquakes. Newly developed ocean-bottom tsunami networks such as S-net and DONET have dramatically changed the above situation for the following two reasons: (1) tsunami propagations are now directly observed in a 2-D array manner without being suffered by complex "site effects" of sea shore, and (2) initial tsunami features can be directly detected just above a fault area. Removing the incompressibility assumption of sea water, we have formulated a new representation of tsunami excitation based on not velocity but displacement components. As a result, not only dynamics but static term (i.e., the component of zero frequency) can be naturally introduced, which is important for the pressure observed on the ocean floor, which ocean-bottom tsunami stations are going to record. The acceleration on the ocean floor should be combined with the conventional tsunami height (that is, the deformation of the sea level above a given station) in the measurement of ocean-bottom pressure although the acceleration exists only during fault motions in time. The M7.2 Off Fukushima earthquake on 22 November 2016 was the first event that excited large tsunamis within the territory of S-net stations. The propagation of tsunamis is found to be highly non-uniform, because of the strong velocity (i.e., sea depth) gradient perpendicular to the axis of Japan Trench. The earthquake was located in a shallow sea close to the coast, so that all the tsunami energy is reflected by the trench region of high velocity. Tsunami records (pressure gauges) within its fault area recorded clear slow motions of tsunamis (i.e., sea level changes) but also large high-frequency signals, as predicted by our theoretical result. That is, it may be difficult to extract tsunami motions from near-fault pressure gauge data immediately after the earthquake occurs, in the sense of tsunami early warning systems.

Development and Application of a Message Metric for NOAA NWS Tsunami Warnings and Recommended Guidelines for the NWS TsunamiReady Program

NASA Astrophysics Data System (ADS)

Gregg, C. E.; Johnston, D. M.; Ricthie, L.; Meinhold, S.; Johnson, V.; Scott, C.; Farnham, C.; Houghton, B. F.; Horan, J.; Gill, D.

2012-12-01

Improving the quality and effectiveness of tsunami warning messages and the TsunamiReady community preparedness program of the US National Oceanic and Atmospheric Administration, National Weather Service's (NWS), Tsunami Program are two key objectives of a three year project (Award NA10NWS4670015) to help integrate social science into the NWS' Tsunami Program and improve the preparedness of member states and territories of the National Tsunami Hazard Mitigation Program (NTHMP). Research was conducted in collaboration with state and local emergency managers. Based on findings from focus group meetings with a purposive sample of local, state and Federal stakeholders and emergency managers in six states (AK, WA, OR, CA, HI and NC) and two US Territories (US Virgin Islands and American Samoa), and upon review of research literature on behavioral response to warnings, we developed a warning message metric to help guide revisions to tsunami warning messages issued by the NWS' West Coast/Alaska Tsunami Warning Center, Alaska and Pacific Tsunami Warning Center, Hawaii. The metric incorporates factors that predict response to warning information, which are divided into categories of Message Content, Style, Order and Formatting and Receiver Characteristics. A message is evaluated by cross-referencing the message with the meaning of metric factors and assigning a maximum score of one point per factor. Findings are then used to guide revisions of the message until the characteristics of each factor are met. From focus groups that gathered information on the usefulness and achievability of tsunami preparedness actions, we developed recommendations for revisions to the proposed draft guidelines of the TsunamiReady Improvement Program. Proposed key revisions include the incorporation of community vulnerability to distant (far-field) versus local (near-field) tsunamis as a primary determinant of mandatory actions, rather than community population. Our team continues to work with NWS personnel, including a NWS Tsunami Warning Improvement Team, and the focus group participants to finalize and pilot test prototype warning products and the draft TsunamiReady guidelines.

Streamlining Tsunami Messages (e.g., Warnings) of the US National Tsunami Warning Center, Palmer, Alaska

NASA Astrophysics Data System (ADS)

Gregg, C. E.; Sorensen, J. H.; Vogt Sorensen, B.; Whitmore, P.; Johnston, D. M.

2016-12-01

Spurred in part by world-wide interest in improving warning messaging for and response to tsunamis in the wake of several catastrophic tsunamis since 2004 and growing interest at the US National Weather Service (NWS) to integrate social science into their Tsunami Program, the NWS Tsunami Warning Centers in Alaska and Hawaii have made great progress toward enhancing tsunami messages. These include numerous products, among them being Tsunami Warnings, Tsunami Advisories and Tsunami Watches. Beginning in 2010 we have worked with US National Tsunami Hazard Mitigation Program (NTHMP) Warning Coordination and Mitigation and Education Subcommittee members; Tsunami Program administrators; and NWS Weather Forecast Officers to conduct a series of focus group meetings with stakeholders in coastal areas of Alaska, American Samoa, California, Hawaii, North Carolina, Oregon, US Virgin Islands and Washington to understand end-user perceptions of existing messages and their existing needs in message products. We also reviewed research literature on behavioral response to warnings to develop a Tsunami Warning Message Metric that could be used to guide revisions to tsunami warning messages of both warning centers. The message metric is divided into categories of Message Content, Style, Order, Formatting, and Receiver Characteristics. A sample message is evaluated by cross-referencing the message with the operational definitions of metric factors. Findings are then used to guide revisions of the message until the characteristics of each factor are met, whether the message is a full length or short message. Incrementally, this work contributed to revisions in the format, content and style of message products issued by the National Tsunami Warning Center (NTWC). Since that time, interest in short warning messages has continued to increase and in May 2016 the NTWC began efforts to revise message products to take advantage of recent NWS policy changes allowing use of mixed-case text format and expanded punctuation, a practice which the NWS first started in 2010. Here we describe our application of a modification of the warning message metric to develop new streamlined messages using mixed-case text. These messages reflect current state-of-the-art knowledge on warning message effectiveness.

Observations and Modeling of Environmental and Human Damages by the 2004 Indian Ocean tsunami

NASA Astrophysics Data System (ADS)

Goto, K.; Imamura, F.; Koshimura, S.; Yanagisawa, H.

2008-05-01

On 26 December 2004, one of the largest tsunamis in human history (the 2004 Indian Ocean tsunami) struck coastal areas of countries surrounding the Indian Ocean, causing severe property damage and loss of life and causing us to think anew about the fearful consequences of a tsunami disaster. The tsunami devastated more than 10 countries around the ocean including Indonesia, Sri Lanka, India, and Thailand. Since its energy remains almost constant, the tsunami wave height grows tremendously in shallow water. It ranged in runups of ~48m on the western shore of Sumatra, ~18m in Thailand, and ~15m in Sri Lanka. The tsunami killed nearly 230,000 people, including visitors from foreign countries, resulting in great economic losses. The tsunami was also affected coastal environment at these countries and induced severe topographic change, and damages to the marine ecosystems as well as vegetations on land. Immediately following the tsunami, number of research teams has investigated damages of environment and human communities by tsunamis. Numerical analyses of tsunami propagation have also been carried out to understand the behavior and wave properties of tsunamis. However, there are few studies that focused on the integration of the field observations and numerical results, nevertheless that such analysis is critically important to evaluate the environmental and human damages by the tsunami. In this contribution, we first review damages to the environment and humans due to the 2004 Indian Ocean tsunami at Thailand, Indonesia, and Sri Lanka based on our field observations, and then we evaluate these damages based on high resolution numerical results. For example, we conducted field observation as well as high-resolution (17 m grid cells) numerical calculation for damages of corals (reef rocks) and mangroves at Pakarang Cape, Thailand. We found that hundreds of reef rocks were emplaced on the tidal bench, and 70 % of mangroves were destroyed at the cape. Our numerical results further clarified that these damages are well explained by the calculated hydraulic force of tsunamis. This kind of analysis that integrated the observation and numerical results is important to evaluate environmental and human damages quantitatively, and to make a future disaster prevention plan.

Hydraulic experiment on formation mechanism of tsunami deposit and verification of sediment transport model for tsunamis

NASA Astrophysics Data System (ADS)

Yamamoto, A.; Takahashi, T.; Harada, K.; Sakuraba, M.; Nojima, K.

2017-12-01

An underestimation of the 2011 Tohoku tsunami caused serious damage in coastal area. Reconsideration for tsunami estimation needs knowledge of paleo tsunamis. The historical records of giant tsunamis are limited, because they had occurred infrequently. Tsunami deposits may include many of tsunami records and are expected to analyze paleo tsunamis. However, present research on tsunami deposits are not able to estimate the tsunami source and its magnitude. Furthermore, numerical models of tsunami and its sediment transport are also important. Takahashi et al. (1999) proposed a model of movable bed condition due to tsunamis, although it has some issues. Improvement of the model needs basic data on sediment transport and deposition. This study investigated the formation mechanism of tsunami deposit by hydraulic experiment using a two-dimensional water channel with slope. In a fixed bed condition experiment, velocity, water level and suspended load concentration were measured at many points. In a movable bed condition, effects of sand grains and bore wave on the deposit were examined. Yamamoto et al. (2016) showed deposition range varied with sand grain sizes. In addition, it is revealed that the range fluctuated by number of waves and wave period. The measurements of velocity and water level showed that flow was clearly different near shoreline and in run-up area. Large velocity by return flow was affected the amount of sand deposit near shoreline. When a cutoff wall was installed on the slope, the amount of sand deposit repeatedly increased and decreased. Especially, sand deposit increased where velocity decreased. Takahashi et al. (1999) adapted the proposed model into Kesennuma bay when the 1960 Chilean tsunami arrived, although the amount of sand transportation was underestimated. The cause of the underestimation is inferred that the velocity of this model was underestimated. A relationship between velocity and sediment transport has to be studied in detail, but observation of velocity in Kesennnuma bay had a low accuracy. On the other hand, this hydraulic experiment measured accurate velocity and sand deposition distribution of various condition. Based on these data, we tried more accurate verification of the model of Takahashi et al. (1999).

The Study to Improve Tsunami Preparedness Education in Turkey

NASA Astrophysics Data System (ADS)

Sakamoto, Mayumi; Tanırcan, Gülüm; Kaneda, Yoshiyuki; Puskulcu, Seyhun; Kumamoto, Kunihiko

2016-04-01

Compared to its long history on disastrous earthquakes, disaster education history in Turkey is rather short. It has just started with an initiative of Disaster Preparedness Education Unit of Bogazici University (BU/DPEU) after 1999 Kocaeli Earthquake. Training modules and materials on disaster preparedness were prepared both for students, teachers and community. Regarding to the school education, the Ministry of National Education (MoNE) reformed their education plan in 2003, and disaster education became one of eight focused components for primary-middle education. In 2011-2014 MoNE had conducted "School-based Disaster Education Project" in collaboration with Japan International Cooperation Agency (JICA). The majority of the school education materials focus more on earthquake and there are very few education programs on tsunami. Within the MarDiM (Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey) project between Turkey and Japan a multidisciplinary engineering research as well as development of disaster education, tsunami education booklet and video were newly developed in 2015. In order to investigate students' knowledge natural disasters and disaster preparedness with focus on tsunami, a questionnaire based survey was conducted. The survey aims to clarify following questions: 1) how students obtain natural disaster information, 2) how students prepare for natural disaster, 3) knowledge on tsunami (hazard mechanism, evacuation behavior, historical disaster). The study was conducted by BU/DPEU in 2015 and 375 students answered the questionnaire. Results showed that students have more interest on earthquake, flood, tsunami and landslide followed it. Most students have heard about tsunami and the school is a key resource of their information. They know relatively well about tsunami mechanism, however, they have less knowledge on tsunami evacuation behavior and tsunami history in Turkey. In order to let students have more knowledge on tsunami, tsunami class was provided by BU/DPEU using tsunami booklet and videos. The class was evaluated by before/after class tests and the result showed improvement on students' knowledge. The result showed the necessity to integrate tsunami education materials in school disaster education curriculum.

Spatiotemporal patterns in community structure of macroinvertebrates inhabiting calcareous periphyton mats

USGS Publications Warehouse

Liston, S.E.; Trexler, J.C.

2005-01-01

Calcareous floating periphyton mats in the southern Everglades provide habitat for a diverse macroinvertebrate community that has not been well characterized. Our study described this community in an oligotrophic marsh, compared it with the macroinvertebrate community associated with adjacent epiphytic algae attached to macrophytes in the water column, and detected spatial patterns in density and community structure. The floating periphyton mat (floating mat) and epiphytic algae in the water column (submerged epiphyton) were sampled at 4 sites (???1 km apart) in northern Shark River Slough, Everglades National Park (ENP), in the early (July) and late (November) wet season. Two perpendicular 90-m transects were established at each site and ???100 samples were taken in a nested design. Sites were located in wet-prairie spikerush-dominated sloughs with similar water depths and emergent macrophyte communities. Floating mats were sampled by taking cores (6-cm diameter) that were sorted under magnification to enumerate infauna retained on a 250-??m-mesh sieve and with a maximum dimension >1 mm. Our results showed that floating mats provide habitat for a macroinvertebrate community with higher densities (no. animals/g ash-free dry mass) of Hyalella azteca, Dasyhelea spp., and Cladocera, and lower densities of Chironomidae and Planorbella spp. than communities associated with submerged epiphyton. Densities of the most common taxa increased 3x to 15x from early to late wet season, and community differences between the 2 habitat types became more pronounced. Floating-mat coverage and estimated floating-mat biomass increased 20 to 30%, and 30 to 110%, respectively, at most sites in the late wet season. Some intersite variation was observed in individual taxa, but no consistent spatial pattern in any taxon was detected at any scale (from 0.2 m to 3 km). Floating mats and their resident macroinvertebrate communities are important components in the Everglades food web. This community should be included in environmental monitoring programs because degradation and eventual loss of the calcareous periphyton mat is associated with P enrichment in this ecosystem. ?? 2005 by The North American Benthological Society.

Assessing the impact of microfinance programming on children: an evaluation from post-tsunami Aceh.

PubMed

Stark, Lindsay; Kassim, Nafessa; Sparling, Thalia; Buscher, Dale; Yu, Gary; Boothby, Neil

2015-04-01

This paper presents an evaluation of the long-term impact of microfinance programmes on Acehnese children during the post-tsunami recovery. The study, conducted from June to August 2010, examined the impact of microfinance programming six years after the tsunami. The sample consisted of 185 microfinance participants, with a comparison group of 192 individuals who did not participate in microfinance programmes. All respondents were parents, interviewed through a structured survey. The study used four child protection indicators-diet, health, childcare and education-in contrast to traditional repayment rate indicators. The primary results were insignificant with respect to all four child protection indicators, suggesting that, with respect to these indicators, there was no long-term difference between the impact of microfinance on beneficiaries' children and non-beneficiaries' children. These findings signify a need for microfinance actors to move beyond traditional indicators of economic success to evaluate the social changes microfinance programmes are presumed to effect. © 2015 The Author(s). Disasters © Overseas Development Institute, 2015.

Modelling of historical tsunami in Eastern Indonesia: 1674 Ambon and 1992 Flores case studies

NASA Astrophysics Data System (ADS)

Pranantyo, Ignatius Ryan; Cummins, Phil; Griffin, Jonathan; Davies, Gareth; Latief, Hamzah

2017-07-01

In order to reliably assess tsunami hazard in eastern Indonesia, we need to understand how historical events were generated. Here we consider two such events: the 1674 Ambon and the 1992 Flores tsunamis. Firstly, Ambon Island suffered a devastating earthquake that generated a tsunami with 100 m run-up height on the north coast of the island in 1674. However, there is no known active fault around the island capable of generating such a gigantic wave. Rumphius' report describes that the initial wave was coming from three villages that collapsed immediately after the earthquake with width as far as a musket shot. Moreover, a very high tsunami was only observed locally. We suspect that a submarine landslide was the main cause of the gigantic tsunami on the north side of Ambon Island. Unfortunately, there is no data available to confirm if landslide have occurred in this region. Secondly, several tsunami source models for the 1992 Flores event have been suggested. However, the fault strike is quite different compare to the existing Flores back-arc thrust and has not been well validated against a tide gauge waveform at Palopo, Sulawesi. We considered a tsunami model based on Griffin, et al., 2015, extended with high resolution bathymetry laround Palopo, in order to validate the latest tsunami source model available. In general, the model produces a good agreement with tsunami waveforms, but arrives 10 minutes late compared to observed data. In addition, the source overestimates the tsunami inundation west of Maumere, and does not account for the presumed landslide tsunami on the east side of Flores Island.

Impact of huge tsunami in March 2011 on seaweed bed distributions in Shizugawa Bay, Sanriku Coast, revealed by remote sensing

NASA Astrophysics Data System (ADS)

Sakamoto, Shingo X.; Sasa, Shuji; Sawayama, Shuhei; Tsujimoto, Ryo; Terauchi, Genki; Yagi, Hiroshi; Komatsu, Teruhisa

2012-10-01

Seaweed beds are very important for abalones and sea urchins as a habitat. In Sanriku Coast, these animals are target species of coastal fisheries. The huge tsunami hit Sanriku Coast facing Pacific Ocean on 11 March 2011. It is needed for fishermen to know present situation of seaweed beds and understand damages of the huge tsunami on natural environments to recover coastal fisheries. We selected Shizugawa Bay as a study site because abalone catch of Shizugawa Bay occupied the first position in Sanriku Coast. To evaluate impact of tsunami on seaweed beds, we compared high spatial resolution satellite image of Shizugawa Bay before the tsunami with that after the tsunami by remote sensing with ground surveys to know impact of the tsunami on seaweed beds. We used two multi-band imageries of commercial high-resolution satellite, Geoeye-1, which were taken on 4 November 2009 before the tsunami and on 22 February 2012 after the tsunami. Although divers observed the tsunami damaged a very small part of Eisenia bicyclis distributions on rock substrates at the bay head, it was not observed clearly by satellite image analysis. On the other hand, we found increase in seaweed beds after the tsunami from the image analysis. The tsunami broke concrete breakwaters, entrained a large amount of rocks and pebble from land to the sea, and disseminated them in the bay. Thus, hard substrates suitable for attachment of seaweeds were increased. Ground surveys revealed that seaweeds consisting of E. bicyclis, Sargassum and Laminaria species grew on these hard substrates on the sandy bottom.

Kuril Islands tsunami of November 2006: 1. Impact at Crescent City by distant scattering

NASA Astrophysics Data System (ADS)

Kowalik, Z.; Horrillo, J.; Knight, W.; Logan, Tom

2008-01-01

A numerical model for the global tsunami computation constructed by Kowalik et al. (2005, 2007a) is applied to the tsunami of November 15, 2006 in the northern Pacific with spatial resolution of one minute. Numerical results are compared to sea level data collected by Pacific DART buoys. The tide gauge at Crescent City (CC) recorded an initial tsunami wave of about 20 cm amplitude and a second larger energy packet arriving 2 hours later. The first energy input into the CC harbor was the primary (direct) wave traveling over the deep waters of the North Pacific. Interactions with submarine ridges and numerous seamounts located in the tsunami path were a larger source of tsunami energy than the direct wave. Travel time for these amplified energy fluxes is longer than for the direct wave. Prime sources for the larger fluxes at CC are interactions with Koko Guyot and Hess Rise. Tsunami waves travel next over the Mendocino Escarpment where the tsunami energy flux is concentrated owing to refraction and directed toward CC. Local tsunami amplification over the shelf break and shelf are important as well. In many locations along the North Pacific coast, the first arriving signal or forerunner has lower amplitude than the main signal, which often is delayed. Understanding this temporal distribution is important for an application to tsunami warning and prediction. As a tsunami hazard mitigation tool, we propose that along with the sea level records (which are often quite noisy), an energy flux for prediction of the delayed tsunami signals be used.

Using Darwin's theory of atoll formation to improve tsunami hazard mitigation in the Pacific

NASA Astrophysics Data System (ADS)

Goff, J. R.; Terry, J. P.

2012-12-01

It is 130 years since Charles Darwin's death and 176 years since he his penned his subsidence theory of atoll formation on 12th April 1836 during the voyage of the Beagle through the Pacific. This theory, founded on the premise of a subsiding volcano and the corresponding upward growth of coral reef, was astonishing for the time considering the absence of an underpinning awareness of plate tectonics. Furthermore, with the exception of the occasional permutation and opposing idea his theory has endured and has an enviable longevity amongst paradigms in geomorphology. In his theory, Darwin emphasised the generally circular morphology of the atoll shape and surprisingly, the validity of this simple morphological premise has never been questioned. There are however, few atolls in the Pacific Ocean that attain such a simple morphology with most manifesting one or more arcuate 'bight-like' structures (ABLSs). These departures from the circular form complicate his simplistic model and are indicative of geomorphological processes in the Pacific Ocean which cannot be ignored. ABLSs represent the surface morphological expression of major submarine failures of atoll volcanic foundations. Such failures can occur during any stage of atoll formation and are a valuable addition to Darwin's theory because they indicate the instability of the volcanic foundations. It is widely recognized in the research community that sector/flank collapses of island edifices are invariably tsunamigenic and yet we have no clear understanding of how significant such events are in the tsunami hazard arena. The recognition of ABLSs however, now offers scientists the opportunity to establish a first order database of potential local and regional tsunamigenic sources associated with the sector/flank collapses of island edifices. We illustrate the talk with examples of arcuate 'bight-like' structures and associated tsunamis in atoll and atoll-like environments. The implications for our understanding of tsunami hazards are profound. In essence, at present we are seriously under-estimating the significance of locally and regionally generated tsunamis throughout the entire Pacific Ocean, but we now have the opportunity to enhance our understanding of such events.

Deflection of Resilient Materials for Reduction of Floor Impact Sound

PubMed Central

Lee, Jung-Yoon; Kim, Jong-Mun

2014-01-01

Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor. PMID:25574491

Deflection of resilient materials for reduction of floor impact sound.

PubMed

Lee, Jung-Yoon; Kim, Jong-Mun

2014-01-01

Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor.

Earthquake mechanism and seafloor deformation for tsunami generation

USGS Publications Warehouse

Geist, Eric L.; Oglesby, David D.; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

2014-01-01

Tsunamis are generated in the ocean by rapidly displacing the entire water column over a significant area. The potential energy resulting from this disturbance is balanced with the kinetic energy of the waves during propagation. Only a handful of submarine geologic phenomena can generate tsunamis: large-magnitude earthquakes, large landslides, and volcanic processes. Asteroid and subaerial landslide impacts can generate tsunami waves from above the water. Earthquakes are by far the most common generator of tsunamis. Generally, earthquakes greater than magnitude (M) 6.5–7 can generate tsunamis if they occur beneath an ocean and if they result in predominantly vertical displacement. One of the greatest uncertainties in both deterministic and probabilistic hazard assessments of tsunamis is computing seafloor deformation for earthquakes of a given magnitude.

Dynamic Tsunami Data Assimilation (DTDA) Based on Green's Function: Theory and Application

NASA Astrophysics Data System (ADS)

Wang, Y.; Satake, K.; Gusman, A. R.; Maeda, T.

2017-12-01

Tsunami data assimilation estimates the tsunami arrival time and height at Points of Interest (PoIs) by assimilating tsunami data observed offshore into a numerical simulation, without the need of calculating initial sea surface height at the source (Maeda et al., 2015). The previous tsunami data assimilation has two main problems: one is that it requires quite large calculating time because the tsunami wavefield of the whole interested region is computed continuously; another is that it relies on dense observation network such as Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET) in Japan or Cascadia Initiative (CI) in North America (Gusman et al., 2016), which is not practical for some area. Here we propose a new approach based on Green's function to speed up the tsunami data assimilation process and to solve the problem of sparse observation: Dynamic Tsunami Data Assimilation (DTDA). If the residual between the observed and calculated tsunami height is not zero, there will be an assimilation response around the station, usually a Gaussian-distributed sea surface displacement. The Green's function Gi,j is defined as the tsunami waveform at j-th grid caused by the propagation of assimilation response at i-th station. Hence, the forecasted waveforms at PoIs are calculated as the superposition of the Green's functions. In case of sparse observation, we could use the aircraft and satellite observations. The previous assimilation approach is not practical because it costs much time to assimilate moving observation, and to compute the tsunami wavefield of the interested region. In contrast, DTDA synthesizes the waveforms quickly as long as the Green's functions are calculated in advance. We apply our method to a hypothetic earthquake off the west coast of Sumatra Island similar to the 2004 Indian Ocean earthquake. Currently there is no dense observation network in that area, making it difficult for the previous assimilation approach. We used DTDA with aircraft and satellite observation above the Indian Ocean, to forecast the tsunami in Sri Lanka, India and Thailand. It shows that DTDA provides reliable tsunami forecasting for these countries, and the tsunami early warning can be issued half an hour before the tsunami arrives to reduce the damage along the coast.

Development of new tsunami detection algorithms for high frequency radars and application to tsunami warning in British Columbia, Canada

NASA Astrophysics Data System (ADS)

Grilli, S. T.; Guérin, C. A.; Shelby, M. R.; Grilli, A. R.; Insua, T. L.; Moran, P., Jr.

2016-12-01

A High-Frequency (HF) radar was installed by Ocean Networks Canada in Tofino, BC, to detect tsunamis from far- and near-field seismic sources; in particular, from the Cascadia Subduction Zone. This HF radar can measure ocean surface currents up to a 70-85 km range, depending on atmospheric conditions, based on the Doppler shift they cause in ocean waves at the Bragg frequency. In earlier work, we showed that tsunami currents must be at least 0.15 m/s to be directly detectable by a HF radar, when considering environmental noise and background currents (from tide/mesoscale circulation). This limits a direct tsunami detection to shallow water areas where currents are sufficiently strong due to wave shoaling and, hence, to the continental shelf. It follows that, in locations with a narrow shelf, warning times using a direct inversion method will be small. To detect tsunamis in deeper water, beyond the continental shelf, we proposed a new algorithm that does not require directly inverting currents, but instead is based on observing changes in patterns of spatial correlations of the raw radar signal between two radar cells located along the same wave ray, after time is shifted by the tsunami propagation time along the ray. A pattern change will indicate the presence of a tsunami. We validated this new algorithm for idealized tsunami wave trains propagating over a simple seafloor geometry in a direction normally incident to shore. Here, we further develop, extend, and validate the algorithm for realistic case studies of seismic tsunami sources impacting Vancouver Island, BC. Tsunami currents, computed with a state-of-the-art long wave model are spatially averaged over cells aligned along individual wave rays, located within the radar sweep area, obtained by solving the wave geometric optic equation; for long waves, such rays and tsunami propagation times along those are only function of the seafloor bathymetry, and hence can be precalculated for different incident tsunami directions. A model simulating the radar backscattered signal in space and time as a function of simulated tsunami currents is applied to the sweep area. Numerical experiments show that the new algorithm can detect a realistic tsunami further offshore than a direct detection method. Correlation thresholds for tsunami detection will be derived from the results.

Earthquake and Tsunami planning, outreach and awareness in Humboldt County, California

NASA Astrophysics Data System (ADS)

Ozaki, V.; Nicolini, T.; Larkin, D.; Dengler, L.

2008-12-01

Humboldt County has the longest coastline in California and is one of the most seismically active areas of the state. It is at risk from earthquakes located on and offshore and from tsunamis generated locally from faults associated with the Cascadia subduction zone (CSZ), other regional fault systems, and from distant sources elsewhere in the Pacific. In 1995 the California Division of Mines and Geology published the first earthquake scenario to include both strong ground shaking effects and a tsunami. As a result of the scenario, the Redwood Coast Tsunami Work Group (RCTWG), an organization of representatives from government agencies, tribes, service groups, academia and the private sector from the three northern coastal California counties, was formed in 1996 to coordinate and promote earthquake and tsunami hazard awareness and mitigation. The RCTWG and its member agencies have sponsored a variety of projects including education/outreach products and programs, tsunami hazard mapping, signage and siren planning, and has sponsored an Earthquake - Tsunami Education Room at the Humboldt County fair for the past eleven years. Three editions of Living on Shaky Ground an earthquake-tsunami preparedness magazine for California's North Coast, have been published since 1993 and a fourth is due to be published in fall 2008. In 2007, Humboldt County was the first region in the country to participate in a tsunami training exercise at FEMA's Emergency Management Institute in Emmitsburg, MD and the first area in California to conduct a full-scale tsunami evacuation drill. The County has conducted numerous multi-agency, multi-discipline coordinated exercises using county-wide tsunami response plan. Two Humboldt County communities were recognized as TsunamiReady by the National Weather Service in 2007. Over 300 tsunami hazard zone signs have been posted in Humboldt County since March 2008. Six assessment surveys from 1993 to 2006 have tracked preparedness actions and personal awareness of earthquake and tsunami hazards in the county and additional surveys have tracked public awareness and tourist concerns about tsunami hazard signs. Over the thirteen year period covered by the surveys, the percent with houses secured to foundations has increased from 58 to 80 percent, respondents aware of a local tsunami hazard increased from 51 to 73 percent and knowing what the Cascadia subduction zone is from 16 to 42 percent.

Moored offshore structures - evaluation of forces in elastic mooring lines

NASA Astrophysics Data System (ADS)

Crudu, L.; Obreja, D. C.; Marcu, O.

2016-08-01

In most situations, the high frequency motions of the floating structure induce important effects in the mooring lines which affect also the motions of the structure. The experience accumulated during systematic experimental tests and calculations, carried out for different moored floating structures, showed a complex influence of various parameters on the dynamic effects. Therefore, it was considered that a systematic investigation is necessary. Due to the complexity of hydrodynamics aspects of offshore structures behaviour, experimental tests are practically compulsory in order to be able to properly evaluate and then to validate their behaviour in real sea. Moreover the necessity to carry out hydrodynamic tests is often required by customers, classification societies and other regulatory bodies. Consequently, the correct simulation of physical properties of the complex scaled models becomes a very important issue. The paper is investigating such kind of problems identifying the possible simplification, generating different approaches. One of the bases of the evaluation has been found consideringtheresults of systematic experimental tests on the dynamic behaviour of a mooring chain reproduced at five different scales. Dynamic effects as well as the influences of the elasticity simulation for 5 different scales are evaluated together. The paper presents systematic diagrams and practical results for a typical moored floating structure operating as pipe layer based on motion evaluations and accelerations in waves.

Assessment of source probabilities for potential tsunamis affecting the U.S. Atlantic coast

USGS Publications Warehouse

Geist, E.L.; Parsons, T.

2009-01-01

Estimating the likelihood of tsunamis occurring along the U.S. Atlantic coast critically depends on knowledge of tsunami source probability. We review available information on both earthquake and landslide probabilities from potential sources that could generate local and transoceanic tsunamis. Estimating source probability includes defining both size and recurrence distributions for earthquakes and landslides. For the former distribution, source sizes are often distributed according to a truncated or tapered power-law relationship. For the latter distribution, sources are often assumed to occur in time according to a Poisson process, simplifying the way tsunami probabilities from individual sources can be aggregated. For the U.S. Atlantic coast, earthquake tsunami sources primarily occur at transoceanic distances along plate boundary faults. Probabilities for these sources are constrained from previous statistical studies of global seismicity for similar plate boundary types. In contrast, there is presently little information constraining landslide probabilities that may generate local tsunamis. Though there is significant uncertainty in tsunami source probabilities for the Atlantic, results from this study yield a comparative analysis of tsunami source recurrence rates that can form the basis for future probabilistic analyses.

Tsunami Preparedness Along the U.S. West Coast (video)

USGS Publications Warehouse

Filmed and edited by: Loeffler, Kurt; Gesell, Justine

2010-01-01

Tsunamis are a constant threat to the coasts of our world. Although tsunamis are infrequent along the West coast of the United States, it is possible and necessary to prepare for potential tsunami hazards to minimize loss of life and property. Community awareness programs are important, as they strive to create an informed society by providing education and training. This video about tsunami preparedness along the West coast distinguishes between a local tsunami and a distant event and focuses on the specific needs of each region. It offers guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings, who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis. This video was produced by the US Geological Survey (USGS) in cooperation with the California Emergency Management Agency (CalEMA), Oregon Department of Geology and Mineral Industries (DOGAMI), Washington Emergency Management Division (EMD), Marin Office of Emergency Services, and Pacific Gas and Electric (PG&E).

The tsunami source area of the 2003 Tokachi-oki earthquake estimated from tsunami travel times and its relationship to the 1952 Tokachi-oki earthquake

USGS Publications Warehouse

Hirata, K.; Tanioka, Y.; Satake, K.; Yamaki, S.; Geist, E.L.

2004-01-01

We estimate the tsunami source area of the 2003 Tokachi-oki earthquake (Mw 8.0) from observed tsunami travel times at 17 Japanese tide gauge stations. The estimated tsunami source area (???1.4 ?? 104 km2) coincides with the western-half of the ocean-bottom deformation area (???2.52 ?? 104 km2) of the 1952 Tokachi-oki earthquake (Mw 8.1), previously inferred from tsunami waveform inversion. This suggests that the 2003 event ruptured only the western-half of the 1952 rupture extent. Geographical distribution of the maximum tsunami heights in 2003 differs significantly from that of the 1952 tsunami, supporting this hypothesis. Analysis of first-peak tsunami travel times indicates that a major uplift of the ocean-bottom occurred approximately 30 km to the NNW of the mainshock epicenter, just above a major asperity inferred from seismic waveform inversion. Copyright ?? The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences.

Tsunami runup and tide-gauge observations from the 14 November 2016 M7.8 Kaikōura earthquake, New Zealand

NASA Astrophysics Data System (ADS)

Power, William; Clark, Kate; King, Darren N.; Borrero, Jose; Howarth, Jamie; Lane, Emily M.; Goring, Derek; Goff, James; Chagué-Goff, Catherine; Williams, James; Reid, Catherine; Whittaker, Colin; Mueller, Christof; Williams, Shaun; Hughes, Matthew W.; Hoyle, Jo; Bind, Jochen; Strong, Delia; Litchfield, Nicola; Benson, Adrian

2017-07-01

The 2016 M w 7.8 Kaikōura earthquake was one of the largest earthquakes in New Zealand's historical record, and it generated the most significant local source tsunami to affect New Zealand since 1947. There are many unusual features of this earthquake from a tsunami perspective: the epicentre was well inland of the coast, multiple faults were involved in the rupture, and the greatest tsunami damage to residential property was far from the source. In this paper, we summarise the tectonic setting and the historical and geological evidence for past tsunamis on this coast, then present tsunami tide gauge and runup field observations of the tsunami that followed the Kaikōura earthquake. For the size of the tsunami, as inferred from the measured heights, the impact of this event was relatively modest, and we discuss the reasons for this which include: the state of the tide at the time of the earthquake, the degree of co-seismic uplift, and the nature of the coastal environment in the tsunami source region.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deserts, L. des

To develop hydrocarbon fields located in deep waters, several alternatives can be contemplated. Among these alternatives, some of them use surface wellheads while others use subsea wells; some alternatives are using bottom founded structures, while others use floating structures or a combination of both. The purpose of this paper is to try to assess when a compliant tower will be the most appropriate solution to consider. To make this assessment, the different types of compliant towers are recalled, as well as the different types of floating structures. Then some criteria are introduced to compare the different alternatives and to determinemore » when a compliant tower is the most appropriate solution.« less