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Sample records for island tsunami effects

  1. The Effect of the Great Barrier Reef on the Propagation of the 2007 Solomon Islands Tsunami Recorded in Northeastern Australia

    NASA Astrophysics Data System (ADS)

    Baba, Toshitaka; Mleczko, Richard; Burbidge, David; Cummins, Phil R.; Thio, Hong Kie

    2008-12-01

    The effect of offshore coral reefs on the impact from a tsunami remains controversial. For example, field surveys after the 2004 Indian Ocean tsunami indicate that the energy of the tsunami was reduced by natural coral reef barriers in Sri Lanka, but there was no indication that coral reefs off Banda Aceh, Indonesia had any effect on the tsunami. In this paper, we investigate whether the Great Barrier Reef (GBR) offshore Queensland, Australia, may have weakened the tsunami impact from the 2007 Solomon Islands earthquake. The fault slip distribution of the 2007 Solomon Islands earthquake was firstly obtained by teleseismic inversion. The tsunami was then propagated to shallow water just offshore the coast by solving the linear shallow water equations using a staggered grid finite-difference method. We used a relatively high resolution (approximately 250 m) bathymetric grid for the region just off the coast containing the reef. The tsunami waveforms recorded at tide gauge stations along the Australian coast were then compared to the results from the tsunami simulation when using both the realistic 250 m resolution bathymetry and with two grids having fictitious bathymetry: One in which the the GBR has been replaced by a smooth interpolation from depths outside the GBR to the coast (the “No GBR” grid), and one in which the GBR has been replaced by a flat plane at a depth equal to the mean water depth of the GBR (the “Average GBR” grid). From the comparison between the synthetic waveforms both with and without the Great Barrier Reef, we found that the Great Barrier Reef significantly weakened the tsunami impact. According to our model, the coral reefs delayed the tsunami arrival time by 5-10 minutes, decreased the amplitude of the first tsunami pulse to half or less, and lengthened the period of the tsunami.

  2. The 1867 tsunami at the Virgin Islands: observations and simulations

    NASA Astrophysics Data System (ADS)

    Zahibo, N.; Pelinovsky, E.; Yalciner, A.; Kurkin, A.; Kozelkov, A.; Zaitsev, A.

    2003-04-01

    The 1867 Virgin Island Tsunami was of a great effect for the Caribbean Islands. A maximal tsunami height in 10 m was recorded for two coastal locations (Deshayes and Sainte-Rose) in Guadeloupe. The historical data of this event for the Caribbean Sea is discussed. The modelling of the 1867 tsunami is performed in the framework of the nonlinear shallow-water theory. Several possible locations of the tsunami source in the Anegada Passage between St. Thomas and St. Croix are examined. According to calculations the waves are significant on Virgin Islands and Puerto Rico (in almost epicentral area), Antigua and Guadeloupe in the northern Lesser Antilles Islands, Grenada and Grenadines in the southern Lesser Antilles Islands. Results of numerical simulations are in good agreement with available historical data.

  3. Extreme tsunami runup simulation at Babi Island due to 1992 Flores tsunami and Okushiri due to 1993 Hokkido tsunami

    NASA Astrophysics Data System (ADS)

    Chule Kim, Dong; Choi, Byung Ho; Kim, Kyeong Ok; Pelinovsky, Efim

    2014-05-01

    This study is based on a series of three dimensional numerical modeling experiments to understand the tsunami run-up and inundation process at the circular shape Babi Island in the Indonesia caused by 1992 Flores earthquake tsunami and at Monai valley in Okushiri Island, west part of East (Japan) Sea caused by the 1993 Hokkaido Nansei-Oki earthquake. The wave field in the coastal area is modeled within the framework of fully nonlinear dispersive Reynolds-averaged Navier-Stokes (RANS) equations solved using the FLOW3D code. Boundary conditions for this model were extracted from computed wave characteristics obtained from the 2D tsunami propagation model based on the shallow water equations. This model has shown it effectivity to explain extreme runup characteristics during the 2004 Indian Ocean tsunami and 2011 Japan tsunami (Kim et al, 2013). In case of the 1992 Flores Island tsunami the results of numerical simulation run-up results are compared with field measured run-up heights. It has good agreement with measurement and computational run-up heights. The particle velocity distribution is also computed. In the case of 1993 Okushiri tsunami the numerical simulation reproduces extreme run-up at the Monai valley (31.7 m).

  4. Reconstruction of the effects of the 2004 Sumatra tsunami on the peculiar morphology of the Seychelles Islands: an application to the island of Praslin

    NASA Astrophysics Data System (ADS)

    Tonini, R.; Tinti, S.; Pagnoni, G.; Gallazzi, S. C.; Armigliato, A.

    2009-12-01

    The Seychelles archipelago is located 1600 km east to the African coasts, in front of Kenya. The 26 December 2004 Sumatra tsunami hit these islands killing two people and causing huge damage to structures and facilities. The impact was more moderate than it could be, because the highest waves arrived during the lowest tide cycle. The difference between low and high tide is about 1.4 meters and this situation limited substantially the inundation inland. The maximun observed runups were no greater than 4 meters above sea level. All the Seychelles islands lie on a very shallow platform. This platform differentiates from the surrounding sea bottom with a rapid change of the bathymetry that leads the ocean depth from 2 km to 70-80 m over a very short horizontal distance. This peculiar morphology of the bathymetry has very interesting effects on the tsunami propagation. In facts the platform is capable of modifying significantly the tsunami signal with respect to the surrounding open sea. The main island of the archipelago is Mahé. Here the tsunami was recorded by the Pointe La Rue station that is located at the end of the international airport in the east side of the island. Praslin is the second largest island of the group of the Seychelles Archipelago and it was chosen as benchmark for testing numerical models by the research teams involved in the framework of the EU-funded SCHEMA (Scenarios for Hazard-induced Emergencies Management) project. The Tsunami Research Team of the Bologna University, Italy, is partner in the project and here it presents the results obtained for Praslin, computing the inundation maps for the 2004 case, basing on the source model proposed by PMEL/NOAA (M=9.3, average slip 18 m, L=700 km, W=100-150 km). Here we present the results concerning the propagation and inundation in the island of Praslin that have been computed by means of the UBO-TSUFD code developed and maintained by the Tsunami Research Team of the University of Bologna. The code

  5. The tsunami effects of a volcanic island flank collapse on a semi-enclosed basin: The Pico-São Jorge channel in the Azores archipelago

    NASA Astrophysics Data System (ADS)

    Quartau, R.; Omira, R.; Ramalho, I.; Baptista, M. A.; Mitchell, N. C.

    2015-12-01

    The Azores archipelago is a set of nine volcanic islands in the middle of the North Atlantic, close to the triple junction between the North American, Eurasian and African plates. Due to their location, the islands are seismic and volcanically active, which makes them especially vulnerable to these types of hazards that could eventually trigger flank collapses, capable of generating destructive tsunamis. However, solid evidence of large-scale flank collapses has only been found recently in Pico Island (Costa et al., 2014; Quartau et al., 2015). This study investigates for the first time the tsunami effects of a flank collapse of the northeastern subaerial slope of Pico Island that occurred more than 70 ka ago. We first reconstructed the pre-event sub-aerial morphology of the island, and then numerically model the flank failure involving an estimated volume of ~8 km3, its flow toward and under the sea of ~14 km, and the subsequent tsunami generation and propagation. The modelling suggests that the collapse of Pico created a mega-tsunami that significantly impacted the coast of adjacent São Jorge Island only after 7 minutes after generation, with wave run-up reaching a maximum of 50 m at some coastlines. Most of the tsunami energy became trapped in the semi-enclosed basin between Pico and São Jorge Islands, with only relatively little energy escaping to neighboring islands. Acknowledgments The author wishes to acknowledge 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)" for its major contribution for the success of this study. Publication supported by project FCT UID/GEO/50019/2013 - Instituto Dom Luiz. The author also acknowledges Fundação Luso-Americana para o Desenvolvimento for supporting the participation in the meeting.

  6. Tsunami damage along the Andaman Islands coasts

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Among the first places to be affected by the massive tidal wave that ripped across the Indian Ocean on December 26, 2004, were the Andaman Islands. Located approximately 850 kilometers north of the epicenter of the earthquake that triggered the tsunami, the islands were not only among the first land masses to be swept under the wave, they have also been rattled by a series of aftershocks. Administrated by the Indian government, about 300,000 people live on the remote island chain, including several indigenous tribes. As of January 3, over 6,000 were confirmed dead or missing in the Andaman Islands. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows the Andaman Islands on January 3, 2005. Compared to previous images of the islands, the beaches along the west side of the islands have been stripped bare, leaving a strip of bright tan land along the coast. The change is most notable on North Sentinel Island, home of the Sentinelese aboriginals, and on Interview Island, where the formerly green coastline has been replaced with an abnormally bright ring of bare sand. The large image reveals additional damage along all the islands of the Andaman chain.

  7. Transformation of tsunami waves passing through the Straits of the Kuril Islands

    NASA Astrophysics Data System (ADS)

    Kostenko, Irina; Kurkin, Andrey; Pelinovsky, Efim; Zaytsev, Andrey

    2015-04-01

    Pacific ocean and themselves Kuril Islands are located in the zone of high seismic activity, where underwater earthquakes cause tsunamis. They propagate across Pacific ocean and penetrates into the Okhotsk sea. It is natural to expect that the Kuril Islands reflect the Okhotsk sea from the Pacific tsunami waves. It has long been noted that the historical tsunami appeared less intense in the sea of Okhotsk in comparison with the Pacific coast of the Kuril Islands. Despite the fact that in the area of the Kuril Islands and in the Pacific ocean earthquakes with magnitude more than 8 occur, in the entire history of observations on the Okhotsk sea coast catastrophic tsunami was not registered. The study of the peculiarities of the propagation of historical and hypothetical tsunami in the North-Eastern part of the Pacific ocean was carried out in order to identify level of effect of the Kuril Islands and Straits on them. Tsunami sources were located in the Okhotsk sea and in the Pacific ocean. For this purpose, we performed a series of computational experiments using two bathymetries: 1) with use Kuril Islands; 2) without Kuril Islands. Magnitude and intensity of the tsunami, obtained during numerical simulation of height, were analyzed. The simulation results are compared with the observations. Numerical experiments have shown that in the simulation without the Kuril Islands tsunamis in the Okhotsk sea have higher waves, and in the Central part of the sea relatively quickly damped than in fact. Based on shallow-water equation tsunami numerical code NAMI DANCE was used for numerical simulations. This work was supported by ASTARTE project.

  8. 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.

  9. Field survey of the 1994 Mindoro Island, Philippines tsunami

    NASA Astrophysics Data System (ADS)

    Imamura, Fumihiko; Synolakis, Costas E.; Gica, Edison; Titov, Vasily; Listanco, Eddie; Lee, Ho Jun

    1995-09-01

    This is a report of the field survey of the November 15, 1994 Mindoro Island, Philippines, tsunami generated by an earthquake ( M=7.0) with a strike-slip motion. We will report runup heights from 54 locations on Luzon, Mindoro and other smaller islands in the Cape Verde passage between Mindoro and Luzon. Most of the damage was concentrated along the northern coast of Mindoro. Runup height distribution ranged 3 4 m at the most severely damaged areas and 2 4 in neighboring areas. The tsunami-affected area was limited to within 10 km of the epicenter. The largest recorded runup value of 7.3 m was measured on the southwestern coast of Baco Island while a runup of 6.1 m was detected on its northern coastline. The earthquake and tsunami killed 62 people, injured 248 and destroyed 800 houses. As observed in other recent tsunami disasters, most of the casualties were children. Nearly all eyewitnesses interviewed described the first wave as a leading-depression wave. Eyewitnesses reported that the main direction of tsunami propagation was SW in Subaang Bay, SE in Wawa and Calapan, NE on Baco Island and N on Verde Island, suggesting that the tsunami source area was in the southern Pass of Verde Island and that the wave propagated rapidly in all directions. The fault plane extended offshore to the N of Mindoro Island, with its rupture originating S of Verde Island and propagating almost directly south to the inland of Mindoro, thereby accounting for the relatively limited damage area observed on the N of Mindoro.

  10. Processing of the Tsunami Catalogue for Martinique Island

    NASA Astrophysics Data System (ADS)

    Roger, J.; Accary, F.

    2010-12-01

    A part of the French West Indies, the Martinique Island is known to be affected by natural hazards like hurricanes and heavy rains, and more specifically by earthquakes, landslides and volcanic eruptions directly linked to the complex tectonic activity in the Caribbean. Destructive tsunami waves have been widely associated to local geological events such as the St Vincent volcano's eruption (1902), or distant events such as the Lisbon teletsunami in 1755. In this study, a classification of the tsunamis having occurred in the Martinique Island since its colonization by the European in 1502 has been realized. It is based on historical accounts and previous scientific studies. It allows to identify the potentially tsunamigenic regions (and associated features as faults, volcanoes,etc.) and the areas on the Martinique Island which could be affected by such waves. With the fast growth of costal urbanization linked to the increasing tourism in the Martinique Island (heliotropism), the tsunami risk increases constantly. In this context, a preliminary study of coastal vulnerability to tsunami hazard has been carried out in the city of La Trinité (eastern coast). It aims at estimating whether the risks represented by tsunamis had been correctly taken into consideration into hazard preparedness plans for the Martinique Island.

  11. Health Effects of Tsunamis

    MedlinePlus

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  12. Tsunami range long wave measurements near the South Kurils Islands

    NASA Astrophysics Data System (ADS)

    Levin, B. V.; Chernov, A. G.; Shevchenko, G. V.; Kovalev, P. D.; Kovalev, D. P.; Kurkin, A. A.; Likhacheva, O. N.; Shishkin, A. A.

    2009-04-01

    The results of long wave measurements data analysis are provided. Autonomous bottom pressure gauges were installed in the Tsrekovnaya bay (Shikotan Island), near the Lovtscova cape (Kunashir Island), Van-Der-Linda cape and Kastrikum cape (Urup Island). The results of three month observations show complicated and ambiguous type of long waves changeability in the different points of the Kuril's islands affected by meteorological and seismological sources. Essential distinctions in the spectral characteristics of long waves `on the different gauges under influence of cyclone and weak tsunami of September 11, 2008 were exposed. It happens because of frequency-selective properties of the ocean area.

  13. Coral reefs as buffers during the 2009 South Pacific tsunami, Upolu Island, Samoa

    NASA Astrophysics Data System (ADS)

    McAdoo, Brian G.; Ah-Leong, Joyce Samuelu; Bell, Lui; Ifopo, Pulea; Ward, Juney; Lovell, Edward; Skelton, Posa

    2011-07-01

    The coral reef bordering the coastline of Samoa affected by the 29 September 2009 tsunami provides a variety of ecosystem services — from nurseries for fisheries and inshore source of food for local communities, to aesthetics for tourists, and the width of the lagoon may have been a factor in reducing the onshore wave height. To understand the complex interactions between the onshore human population and the offshore coral, we formed an interdisciplinary survey team to document the effects the tsunami had on the nearshore coral reef, and how these changes might affect local inhabitants. The scale of reef damage varied from severe, where piles of freshly-killed coral fragments and mortality were present, to areas that exhibited little impact, despite being overrun by the tsunami. We found that many coral colonies were impacted by tsunami-entrained coral debris, which had been ripped up and deposited on the fore reef by repeated cyclones and storm waves. In other places, large surface area tabular coral sustained damage as the tsunami velocity increased as it was funneled through channels. Areas that lacked debris entrained by the waves as well as areas in the lee of islands came through relatively unscathed, with the exception of the delicate corals that lived on a sandy substrate. In the lagoon on the south coast with its steep topography, coral colonies were damaged by tsunami-generated debris from onshore entrained in the backwash. Despite the potential for severe tsunami-related damage, there were no noticeable decreases in live coral cover between successive surveys at two locations, although algal cover was higher with the increased nutrients mobilized by the tsunami. While there was an immediate decrease in fish takes in the month following the tsunami, when supporting services were likely impacted, both volume and income have rapidly increased to pre-tsunami levels. Long-term monitoring should be implemented to determine if nursery services were

  14. Modeling potential tsunami sources for deposits near Unalaska Island, Aleutian Islands

    NASA Astrophysics Data System (ADS)

    La Selle, S.; Gelfenbaum, G. R.

    2013-12-01

    In regions with little seismic data and short historical records of earthquakes, we can use preserved tsunami deposits and tsunami modeling to infer if, when and where tsunamigenic earthquakes have occurred. The Aleutian-Alaska subduction zone in the region offshore of Unalaska Island is one such region where the historical and paleo-seismicity is poorly understood. This section of the subduction zone is not thought to have ruptured historically in a large earthquake, leading some to designate the region as a seismic gap. By modeling various historical and synthetic earthquake sources, we investigate whether or not tsunamis that left deposits near Unalaska Island were generated by earthquakes rupturing through Unalaska Gap. Preliminary field investigations near the eastern end of Unalaska Island have identified paleotsunami deposits well above sea level, suggesting that multiple tsunamis in the last 5,000 years have flooded low-lying areas over 1 km inland. Other indicators of tsunami inundation, such as a breached cobble beach berm and driftwood logs stranded far inland, were tentatively attributed to the March 9, 1957 tsunami, which had reported runup of 13 to 22 meters on Umnak and Unimak Islands, to the west and east of Unalaska. In order to determine if tsunami inundation could have reached the runup markers observed on Unalaska, we modeled the 1957 tsunami using GeoCLAW, a numerical model that simulates tsunami generation, propagation, and inundation. The published rupture orientation and slip distribution for the MW 8.6, 1957 earthquake (Johnson et al., 1994) was used as the tsunami source, which delineates a 1200 km long rupture zone along the Aleutian trench from Delarof Island to Unimak Island. Model results indicate that runup and inundation from this particular source are too low to account for the runup markers observed in the field, because slip is concentrated in the western half of the rupture zone, far from Unalaska. To ascertain if any realistic

  15. Household evacuation characteristics in American Samoa during the 2009 Samoa Islands tsunami

    USGS Publications Warehouse

    Apatu, Emma J. I.; Gregg, Chris E.; Wood, Nathan J.; Wang, Liang

    2016-01-01

    Tsunamis represent significant threats to human life and development in coastal communities. This quantitative study examines the influence of household characteristics on evacuation actions taken by 211 respondents in American Samoa who were at their homes during the 29 September 2009 Mw 8.1 Samoa Islands earthquake and tsunami disaster. Multiple logistic regression analysis of survey data was used to examine the association between evacuation and various household factors. Findings show that increases in distance to shoreline were associated with a slightly decreased likelihood of evacuation, whereas households reporting higher income had an increased probability of evacuation. The response in American Samoa was an effective one, with only 34 fatalities in a tsunami that reached shore in as little as 15 minutes. Consequently, future research should implement more qualitative study designs to identify event and cultural specific determinants of household evacuation behaviour to local tsunamis.

  16. Household evacuation characteristics in American Samoa during the 2009 Samoa Islands tsunami.

    PubMed

    Apatu, Emma J I; Gregg, Chris E; Wood, Nathan J; Wang, Liang

    2016-10-01

    Tsunamis represent significant threats to human life and development in coastal communities. This quantitative study examines the influence of household characteristics on evacuation actions taken by 211 respondents in American Samoa who were at their homes during the 29 September 2009 Mw 8.1 Samoa Islands earthquake and tsunami disaster. Multiple logistic regression analysis of survey data was used to examine the association between evacuation and various household factors. Findings show that increases in distance to shoreline were associated with a slightly decreased likelihood of evacuation, whereas households reporting higher income had an increased probability of evacuation. The response in American Samoa was an effective one, with only 34 fatalities in a tsunami that reached shore in as little as 15 minutes. Consequently, future research should implement more qualitative study designs to identify event and cultural specific determinants of household evacuation behaviour to local tsunamis.

  17. Tsunami awareness saves Solomon Islanders on 1 April 2007

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Kalligeris, N.

    2007-12-01

    On April 1, 2007 at 20:39:56 UTC (local time: UTC+11), a magnitude Ms 8.1 earthquake occurred 50 km off the New Georgia Islands in the Solomon Sea generating a locally focused tsunami striking more than 300 coastal communities in the Solomon Islands. A reconnaissance team deployed within one week investigated 65 coastal settlements on 13 remote Islands and measured run-up heights of 12 m, local flow depths of 5 m as well as tectonic uplift up to 3.6 m and subsidence down to -1.5m. This South Pacific archipelago's worst disaster since WWII resulted in 52 confirmed death and 36'000 directly affected - roughly half of these numbers are children. The ground shaking pinned people to the ground and palm trees bounced back and forth with leafs touching the ground. The ancestral heritage "run to high ground after an earthquake" passed on to younger generations by survivors of a smaller 1952 tsunami triggered an immediate spontaneous self evacuation, which dramatically reduced the death toll in the small evacuation window of a few minutes between the end of the ground shaking and the onslaught of the tsunami. The survivors remained traumatized by the tsunami, afraid of the sea and living in evacuation camps on the hills illustrating the importance of community-based education and awareness programs.

  18. The Solomon Islands tsunami of 6 February 2013 field survey in the Santa Cruz Islands

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Papantoniou, A.; Biukoto, L.; Albert, G.

    2013-12-01

    On February 6, 2013 at 01:12:27 UTC (local time: UTC+11), a magnitude Mw 8.0 earthquake occurred 70 km to the west of Ndendo Island (Santa Cruz Island) in the Solomon Islands. The under-thrusting earthquake near a 90° bend, where the Australian plate subducts beneath the Pacific plate generated a locally focused tsunami in the Coral Sea and the South Pacific Ocean. The tsunami claimed the lives of 10 people and injured 15, destroyed 588 houses and partially damaged 478 houses, affecting 4,509 people in 1,066 households corresponding to an estimated 37% of the population of Santa Cruz Island. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment and coral boulder depositions, land level changes, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 19 to 23 February 2013 ITST covered 30 locations on 4 Islands: Ndendo (Santa Cruz), Tomotu Noi (Lord Howe), Nea Tomotu (Trevanion, Malo) and Tinakula. The reconnaissance completely circling Ndendo and Tinakula logged 240 km by small boat and additionally covered 20 km of Ndendo's hard hit western coastline by vehicle. The collected survey data includes more than 80 tsunami runup and flow depth measurements. The tsunami impact peaked at Manoputi on Ndendo's densely populated west coast with maximum tsunami height exceeding 11 m and local flow depths above ground exceeding 7 m. A fast tide-like positive amplitude of 1 m was recorded at Lata wharf inside Graciosa Bay on Ndendo Island and misleadingly reported in the media as representative tsunami height. The stark contrast between the field observations on exposed coastlines and the Lata tide gauge recording highlights the importance of rapid tsunami reconnaissance surveys. Inundation distance and damage more than 500 m inland were recorded at Lata airport on Ndendo Island. Landslides were

  19. 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

  20. 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.

  1. Landslide-generated tsunamis at Réunion Island

    NASA Astrophysics Data System (ADS)

    Kelfoun, Karim; Giachetti, Thomas; Labazuy, Philippe

    2010-10-01

    Landslides that occur on oceanic volcanoes can reach the sea and trigger catastrophic tsunamis. Réunion Island has been the location of numerous huge landslides involving tens to hundreds of cubic kilometers of material. We use a new two-fluid (seawater and landslide) numerical model to estimate the wave amplitudes and the propagation of tsunamis associated with landslide events on Réunion Island. A 10 km3 landslide from the eastern flank of Piton de la Fournaise volcano would lift the water surface by about 150 m where it entered the sea. The wave thus generated would reach Saint-Denis, the capital of Réunion Island (population of about 150,000 people), in only 12 min, with an amplitude of more than 10 m, and would reach Mauritius Island in 18 min. Although Mauritius is located about 175 km from the impact, waves reaching its coast would be greater than those for Réunion Island. This is due to the initial shape of the wave, and its propagation normal to the coast at Mauritius but generally coast-parallel at Réunion Island. A submarine landslide of the coastal shelf of 2 km3, would trigger a ˜40 m high wave that would severely affect the proximal coast in the western part of Réunion Island. For a landslide of the shelf of only 0.5 km3, waves of about 2 m in amplitude would affect the proximal coast.

  2. Including Tidal Effects in Tsunami Forecasting

    NASA Astrophysics Data System (ADS)

    Arcas, D.

    2015-12-01

    Recently a new tsunami forecast system SIFT (Short-term Inundation and Forecasting of Tsunamis) has been declared operational by the National Weather Service (NWS) Tsunami Warning Centers. The SIFT system assimilates real-time information from a network of observing systems deployed in the open ocean, to produce on-the-fly estimates of tsunami impact at specific coastal communities. These estimates are computed via the tsunami simulation code MOST (Method of Splitting Tsunami) and include forecast products such as tsunami arrival time, duration of the event, predicted tsunami currents, maximum sea surface elevation and expected inundation areas. These computations are performed under the assumption that the mean sea level remains constant at Mean High Water (MHW) during the entire tsunami event. This assumption produces conservative tsunami forecasts that tend to err on the side of caution with the possibility of substantial overestimates of the inundation areas. To avoid this problem and produce more accurate, operational tsunami forecasts, we investigate the effects of tsunami interaction with tides. The nonlinear dynamic interaction is simulated by first, simulating tidal elevations and currents with Oregon State University tidal model, to obtain boundary and initial conditions to force the MOST tsunami model. Tsunami boundary and initial conditions can be added to those for the tide to study the combined effect. Our results show that even at locations with strong tidal forcing, the tsunami/tide interaction effect has a weakly non-linear effect on the tsunami elevation waveform. This interaction, however, will have a significant effect on the extent of the inundation area. Based on these findings we propose a simple, linear correction to the standard MHW forecast for tsunami time series and inundation area, that can be performed on-the-fly by the SIFT system without the need for complex tidal models.

  3. Towards eradication: three years after the tsunami of 2004, has malaria transmission been eliminated from the island of Simeulue?

    PubMed

    Sudomo, Mohammad; Arianti, Yusniar; Wahid, Isra; Safruddin, Din; Pedersen, Erling M; Charlwood, J Derek

    2010-12-01

    The island of Simeulue was the first landfall of the tsunami of December 2004. The tsunami destroyed many villages on the island, leaving one third of the population homeless. Malaria is endemic in Simeulue and an epidemic was reported to have occurred three months prior to the tsunami. Information concerning malaria was, however, not easily available. The earthquakes related to the tsunami may have created extensive potential breeding sites of Anopheles sundaicus, the probable vector, and increased vulnerability of the human population; a possibility of increased transmission made a further outbreak possible. Consequently, subsequent to the tsunami, considerable amounts of aid, including anti-malarial measures such as insecticide treated mosquito-nets, were deployed on the island. A series of island-wide cross-sectional surveys were conducted in 2005-2007 to determine whether these had had any effect on malaria prevalence. Larval sampling, and CDC light-trap and landing collections of hungry mosquitoes were also undertaken. The results indicate that despite the continuing presence of potential vectors in some places the anti-malaria measures introduced following the tsunami have controlled, and may be close to eliminating, malaria from the island.

  4. Tsunami Questionnaire Survey in Heraklion Test Site, Crete Island, Greece

    NASA Astrophysics Data System (ADS)

    Papageorgiou, Antonia; Tsimi, Christina; Orfanogiannaki, Katerina; Papadopoulos, Gerassimos; Sachpazi, Maria; Lavigne, Franck; Grancher, Delphine

    2015-04-01

    The Heraklion city (Crete Island, Greece) has been chosen as one of the test-sites for the EU-FP7ASTARTE tsunami project. Heraklion is the biggest city in Crete Isl. and the fourth biggest in Greece with a population of about 120,000 which, however, during the summer vacation period nearly doubles. In the past, Heraklion was hit by strong, destructive tsunamis such as the ones of AD 8 August 1303, 10 October 1650 and 9 July 1956. The first and the third were caused by large tectonic earthquakes associated with the eastern segment of the Hellenic Arc the first and with the back-arc extensional regime the third. The one of 1650 was associated with the eruption of the Columbo submarine volcano in the Santorini volcanic complex. One of the activities scheduled for WP9 of ASTARTE project, which aims at building tsunami resilient societies in Europe, is dedicated to organize questionnaire surveys among the populations of the several ASTARTE test-sites. Although the questionnaire is comprised by more than 50 questions, the central concept is to better understand what people know about tsunamis and if they are ready to cope with risks associated with future tsunami occurrences. In Heraklion the survey was conducted during tourism peak season of July 2014, thus questionnaires were collected by both local people and tourists, thus representing a variety of countries. We attempted to keep balance between males and females, while the age ranged from 15 to 65. Totally, 113 persons were interviewed of which 62 were females and 51 males. From the point of view of origin, 58 out of 113 were local people and residents, 22 were Greek tourists and 29 foreign tourists. Generally, the questionnaire consists of four parts. In the first, people were asked about their relation with the area of Heraklion. In the second part, the questions considered the knowledge that people have on tsunamis as a natural, hazardous phenomenon. More precisely, people were asked questions such as what a

  5. Tsunamis generated by 3D granular landslides in various scenarios from fjords to conical islands

    NASA Astrophysics Data System (ADS)

    McFall, Brian C.; Fritz, Hermann M.

    2015-04-01

    Landslide generated tsunamis such as in Lituya Bay, Alaska 1958 account for some of the highest recorded tsunami runup heights. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by pneumatic pistons down slope. Two different landslide materials are used to study the granulometry effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified with video image processing. The measured landslide and wave parameters are compared between the planar hill slope used in various scenarios and the convex hill slope of the conical island. The energy conversion rates from the landslide motion to the wave train is quantified for the planar and convex hill slopes. The wave runup data on the opposing headland is analyzed and evaluated with wave theories. The measured landslide and tsunami data serve to validate and advance three-dimensional numerical landslide tsunami prediction models.

  6. Physical Modeling of Landslide Generated Tsunamis in Fjords and around Conical Islands

    NASA Astrophysics Data System (ADS)

    McFall, B. C.; Fritz, H. M.

    2012-12-01

    Froude number and relative landslide shape among others. Energy conversion rates between the landslide motion and the generated wave train are quantified. The lateral edge wave and offshore wave propagation velocities are compared against wave theories. Unique characteristics in the wave and runup data caused by topographic and bathymetric features are analyzed. A localized amplification of the runup was observed on the lee-side of the conical island due to the collision effects of the lateral edge waves propagating around both sides of the island. The measured landslide and tsunami data serve to validate and advance 3-dimensional numerical landslide tsunami prediction models.; Tsunami generation by landslide (Photo credit: Stephanie Lopez)

  7. 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.

  8. Local Tsunami Hazard In The Marquesas Islands (french Polynesia) : Numerical Modeling of The 1999 Fatu Hiva Landslide and Tsunami

    NASA Astrophysics Data System (ADS)

    Hébert, H.; Schindelé, F.; Heinrich, P.; Piatanesi, A.; Okal, E. A.

    In French Polynesia, the Marquesas Islands are particularly prone to amplification of tsunamis generated at the Pacific Rim, due to relatively mild submarine slopes and to large open bays not protected by any coral reef. These islands are also threatened by local tsunamis, as shown by the recent 1999 event on Fatu Hiva. On September 13, 1999, Omoa Bay was struck by 2 to 5 m high water waves: several buildings, among them the school, were flooded and destroyed but no lives were lost. Observations gath- ered during a post-event survey revealed the recent collapse into the sea of a 300x300 m, at least 20-m thick, cliff located 5 km southeast of Omoa. This cliff failure most certainly triggered the tsunami waves since the cliff was reported intact 45 min earlier. We simulate the tsunami generation due to a subaerial landslide, using a finite- difference model assimilating the landslide to a flow of granular material. Numerical modeling shows that a 0.0024-km3 landslide located in the presumed source area ac- counts well for the tsunami waves reported in Omoa Bay. We show that the striking amplification observed in Omoa Bay is related to the trapping of waves due to the shallow submarine shelf surrounding the island. These results stress the local tsunami hazard that should be taken into account in the natural hazard assessment and mitiga- tion of the area, where historical cliff collapses can be observed and should happen again.

  9. Inferring relative tsunami magnitudes from inverse and forward sediment transport modeling of tsunami deposits in the Eastern Aleutian Islands.

    NASA Astrophysics Data System (ADS)

    Gelfenbaum, G. R.; La Selle, S.; Witter, R. C.; Jaffe, B. E.; Briggs, R. W.; Koehler, R. D., III; Engelhart, S. E.; Carver, G. A.

    2014-12-01

    Tsunami recurrence intervals can be determined by age dating paleotsunami deposits, but relative tsunami magnitude is more difficult to infer from deposit characteristics alone. Deposit thickness, grain size, and certain sedimentary structures are used to infer hydrodynamic conditions during deposition, which can be used as proxies for tsunami magnitude. Recent field studies in the eastern Alaska-Aleutian subduction zone have identified sequences of tsunami deposits from the 1957 Andreanof Islands earthquake (MW 8.6) and at least five other pre-historic tsunami events from the last 2,400 years. At Stardust Bay on the Pacific Coast of Sedanka Island, a sand-rich deposit attributed to the 1957 tsunami is 1-13 cm thick and is found at elevations up to 18.5 m. Older sand units are 6-50 cm thick and often have rounded gravel at the base of multiple, normally-graded sand beds. At Driftwood Bay on the south side of Umnak Island, about 200 km to the southeast of Stardust Bay, the 1957 deposit is 1 - 5.5 cm thick, underlain by a sequence of peat with up to 8 sandy deposits, some of which exhibit normally-graded beds up to 14 cm thick. Relatively thick deposits that exhibit suspension grading, a type of grading created by sediment falling out of suspension that is often observed in modern tsunami deposits, are typically formed under steady and uniform flow and are therefore good candidates for reconstructing flow conditions using inverse sediment transport models. By applying forward models of sediment transport, we will test how different tsunami waveforms, wave heights, sediment source distributions, roughness, and local slopes affect patterns of deposition. This will help us assess which deposits have characteristics that scale with tsunami wave heights used as initial conditions in the forward model, and are therefore more indicative of relative tsunami magnitude. Here, we attempt to determine if the tsunamis that created the pre-historic deposits found at Stardust and

  10. Tsunami Runup in the Middle Kuril Islands from the Great Earthquake of 15 Nov 2006

    NASA Astrophysics Data System (ADS)

    Bourgeois, J.; Pinegina, T.; Razhegaeva, N.; Kaistrenko, V.; Levin, B.; Macinnes, B.; Kravchunovskaya, E.

    2007-12-01

    Two expeditions to the middle Kuril Islands [IMGG FED RAS, NSF Kurils Biocomplexity Project] in the summer of 2007 yielded tsunami runup and inundation measurements from the 15 Nov 2006 Mw 8.3 subduction-zone earthquake, and possibly from the 13 Jan 2007 Mw 8.1 earthquake seaward of the subduction zone. Both earthquakes produced measurable tsunamis in the far field, the 13 Jan tsunami significantly smaller; the 15 Nov tsunami did some damage in the harbor of Crescent City, CA. Ours are the first near-source measurements because no one lives in the middle Kurils. Moreover, because KBP visited many of the same sites in summer of 2006, we have numerous before-and-after comparisons, including quantified erosion. We measured 120 profiles and made more than 300 runup measurements. We found dramatic tsunami effects of erosion and deposition, with widespread runup of 8-12 m, up to about 20 m, between and including Simushir and Matua islands. In most cases, we measured runup with a transit and surveying rod, producing a topographic profile from sea level to the slope above runup indicators; in some cases, we used a hand level and tape. Runup/inundation criteria were generally subhorizontal lines of floatable debris, typically wood, plastic, glass floats, and styrofoam. Single occurrences, e.g., of a plastic bottle were not considered adequate. Corroborative evidence, not used independently, included limits of consistently oriented stems of tall grasses and flowers, limit of sand and gravel deposits above turf and dead vegetation, and elevation of fresh erosion of turf from slopes landward of the beach plain. Currently we are compiling, correcting and vetting our measurements, which will be submitted to online databases. Topographic profiles obviously had an effect on the data, with short, steep profiles generating high runup and short inundation; most beach-ridge profiles had longer inundation and shorter runup. However, at Ainu Bay on Matua Island, we found as much as 18

  11. 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

  12. The influence of the Kuril Islands on the penetration of tsunamis into the Sea of Okhotsk (on the example of the Japan tsunami on March 11, 2011)

    NASA Astrophysics Data System (ADS)

    Kostenko, I. S.; Kurkin, A. A.; Pelinovsky, E. N.; Yalciner, A.

    2016-01-01

    The features of the propagation of the tsunami of March 11, 2011 in the northeastern Pacific have been studied with the aim of revealing the degree of influence of the Kuril Islands on the penetration of the tsunami in the Sea of Okhotsk. For this, a series of computational experiments have been performed within the shallow water theory using bathymetry (1) with and (2) without the Kuril Islands. The wave heights calculated have been analyzed, and the tsunami's magnitude and intensity in the Sea of Okhotsk have been estimated. The computational experiments performed allow assessment of a decrease in the tsunami intensity while passing the Kuril Islands.

  13. Damage to coastal villages due to the 1992 Flores Island earthquake tsunami

    NASA Astrophysics Data System (ADS)

    Tsuji, Yoshinobu; Matsutomi, Hideo; Imamura, Fumihiko; Takeo, Minoru; Kawata, Yoshiaki; Matsuyama, Masafumi; Takahashi, Tomoyuki; Sunarjo; Harjadi, Prih

    1995-09-01

    A field survey of the 1992 Flores Island earthquake tsunami was conducted during December 29, 1992 to January 5, 1993 along the north coast of the eastern part of Flores Island. We visited over 40 villages, measured tsunami heights, and interviewed the inhabitants. It was clarified that the first wave attacked the coast within five minutes at most of the surveyed villages. The crust was uplifted west of the Cape of Batumanuk, and subsided east of it. In the residential area of Wuring, which is located on a sand spit with ground height of 2 meters, most wooden houses built on stilts collapsed and 87 people were killed even though the tsunami height reached only 3.2 meters. In the two villages on Babi Island, the tsunami swept away all wooden houses and killed 263 of 1,093 inhabitants. Tsunami height at Riang-Kroko village on the northeastern end of Flores Island reached 26.2 meters and 137 of the 406 inhabitants were killed by the tsumani. Evidence of landslides was detected at a few points on the coast of Hading Bay, and the huge tsunami was probably formed by earthquake-induced landslides. The relationship between tsunami height and mortality was checked for seven villages. The efficiencies of trees arranged in front of coastal villages, and coral reefs in dissipating the tsunami energy are discussed.

  14. The lower ionosphere effects caused by the tsunami-driven internal gravity waves

    NASA Astrophysics Data System (ADS)

    Rozhnoi, Alexander; Solovieva, Maria; Shalimov, Sergei; Levin, Boris; Shevchenko, Georgy; Hayakawa, Masashi

    2014-05-01

    Measurements from the VLF/LF station in Petropavlovsk-Kamchatsky (Russia) were used to observe the response of the lower ionosphere to the tsunami triggered by the 2010 Chili earthquake. This earthquake produced the trans-ocean tsunami, which severely affected the coastal communities of Chile and presented a serious threat for all Pacific Ocean coasts including the far eastern coast of Russia. Disturbances in the phase and amplitude of the VLF signal propagating from the transmitter in Hawaiian Islands were observed during the tsunami wave passage recorded by the Deep-ocean Assessments and Reporting of Tsunamis (DART) bottom pressure stations. The tsunami propagation time from the source to Hawaii Islands was about 14 h and to the coast of Russia about 21 h. The new point discussed here is that we observed a second tsunami and its ionospheric effects which have been missed in the previous observations in the upper ionosphere. Nevertheless, the presence of the second tsunami is confirmed by both the VLF and DART's measurements. The tsunamigenic effects in the ionosphere were compared to the in-situ sea-level DART measurements near Hawaii Islands and not far from Kamchatka. The frequency of the maximum spectral amplitude both for the VLF and DART data was found to be in the range of periods of 8-60 min which corresponds to the period of the internal gravity waves generated by tsunami.

  15. Field Survey of the 29 September 2009 Tsunami on Savai’i Island, Samoa

    NASA Astrophysics Data System (ADS)

    Weiss, R.; Fritz, H. M.

    2009-12-01

    On 29 September, 2009 a magnitude Mw 8.1 earthquake occurred 200 km south of Samoa’s largest island Savai’i and triggered a tsunami which caused substantial damage and loss of life in Samoa, American Samoa and Tonga. The most recent estimate is that the tsunami caused 189 fatalities with the majority on Samoa’s Upolu Island, while only two deaths are confirmed on Savai’i. This marks the deadliest tsunami in Polynesia and Micronesia to the east of New Guinea since the 1975 Bougainville Island tsunami. PTWC responded and issued warnings soon after the earthquake but, because the tsunami arrived within 15 minutes at many locations, was too late to trigger evacuations. Fortunately, the people of Samoa knew to go to high ground after an earthquake because of education and tsunami evacuation exercises initiated throughout the South Pacific after a similar magnitude earthquake and tsunami struck the nearby Solomon Islands in 2007. A multi-disciplinary reconnaissance survey team was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, and performance of the man-made infrastructure and impact on the natural environment. The ITST circled Savai’i Island from 8 to 9 October 2009 and collected more than 30 runup and flow depth measurements. The tsunami impact on Savai’i peaked with maximum runup exceeding 8 m at uninhabited Nuu Black Sand Beach located 7 km east of Cape Asuisui marking the center of the south coast. A significant variation in tsunami impact was observed on Savaii. The tsunami runup reached 6 m at Taga located 3 km to the east of Cape Asuisui, while along the northeast coast the runup remained below 3 m. The inundation distance at Taga approached 200 m and massive boulder fields covered the previously vegetated terrain more than 100 m inland. Fortunately no victims were reported at this location during this event, while the presumably smaller 1981

  16. Physical modelling of tsunamis generated by three-dimensional deformable granular landslides on planar and conical island slopes

    PubMed Central

    2016-01-01

    Tsunamis generated by landslides and volcanic island collapses account for some of the most catastrophic events recorded, yet critically important field data related to the landslide motion and tsunami evolution remain lacking. Landslide-generated tsunami source and propagation scenarios are physically modelled in a three-dimensional tsunami wave basin. A unique pneumatic landslide tsunami generator was deployed to simulate landslides with varying geometry and kinematics. The landslides were generated on a planar hill slope and divergent convex conical hill slope to study lateral hill slope effects on the wave characteristics. The leading wave crest amplitude generated on a planar hill slope is larger on average than the leading wave crest generated on a convex conical hill slope, whereas the leading wave trough and second wave crest amplitudes are smaller. Between 1% and 24% of the landslide kinetic energy is transferred into the wave train. Cobble landslides transfer on average 43% more kinetic energy into the wave train than corresponding gravel landslides. Predictive equations for the offshore propagating wave amplitudes, periods, celerities and lengths generated by landslides on planar and divergent convex conical hill slopes are derived, which allow an initial rapid tsunami hazard assessment. PMID:27274697

  17. Physical modelling of tsunamis generated by three-dimensional deformable granular landslides on planar and conical island slopes

    NASA Astrophysics Data System (ADS)

    McFall, Brian C.; Fritz, Hermann M.

    2016-04-01

    Tsunamis generated by landslides and volcanic island collapses account for some of the most catastrophic events recorded, yet critically important field data related to the landslide motion and tsunami evolution remain lacking. Landslide-generated tsunami source and propagation scenarios are physically modelled in a three-dimensional tsunami wave basin. A unique pneumatic landslide tsunami generator was deployed to simulate landslides with varying geometry and kinematics. The landslides were generated on a planar hill slope and divergent convex conical hill slope to study lateral hill slope effects on the wave characteristics. The leading wave crest amplitude generated on a planar hill slope is larger on average than the leading wave crest generated on a convex conical hill slope, whereas the leading wave trough and second wave crest amplitudes are smaller. Between 1% and 24% of the landslide kinetic energy is transferred into the wave train. Cobble landslides transfer on average 43% more kinetic energy into the wave train than corresponding gravel landslides. Predictive equations for the offshore propagating wave amplitudes, periods, celerities and lengths generated by landslides on planar and divergent convex conical hill slopes are derived, which allow an initial rapid tsunami hazard assessment.

  18. Physical modelling of tsunamis generated by three-dimensional deformable granular landslides on planar and conical island slopes.

    PubMed

    McFall, Brian C; Fritz, Hermann M

    2016-04-01

    Tsunamis generated by landslides and volcanic island collapses account for some of the most catastrophic events recorded, yet critically important field data related to the landslide motion and tsunami evolution remain lacking. Landslide-generated tsunami source and propagation scenarios are physically modelled in a three-dimensional tsunami wave basin. A unique pneumatic landslide tsunami generator was deployed to simulate landslides with varying geometry and kinematics. The landslides were generated on a planar hill slope and divergent convex conical hill slope to study lateral hill slope effects on the wave characteristics. The leading wave crest amplitude generated on a planar hill slope is larger on average than the leading wave crest generated on a convex conical hill slope, whereas the leading wave trough and second wave crest amplitudes are smaller. Between 1% and 24% of the landslide kinetic energy is transferred into the wave train. Cobble landslides transfer on average 43% more kinetic energy into the wave train than corresponding gravel landslides. Predictive equations for the offshore propagating wave amplitudes, periods, celerities and lengths generated by landslides on planar and divergent convex conical hill slopes are derived, which allow an initial rapid tsunami hazard assessment.

  19. The Solomon Islands Tsunami of 6 February 2013 in the Santa Cruz Islands: Field Survey and Modeling

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Papantoniou, Antonios; Biukoto, Litea; Albert, Gilly; Wei, Yong

    2014-05-01

    On February 6, 2013 at 01:12:27 UTC (local time: UTC+11), a magnitude Mw 8.0 earthquake occurred 70 km to the west of Ndendo Island (Santa Cruz Island) in the Solomon Islands. The under-thrusting earthquake near a 90° bend, where the Australian plate subducts beneath the Pacific plate generated a locally focused tsunami in the Coral Sea and the South Pacific Ocean. The tsunami claimed the lives of 10 people and injured 15, destroyed 588 houses and partially damaged 478 houses, affecting 4,509 people in 1,066 households corresponding to an estimated 37% of the population of Santa Cruz Island. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment and coral boulder depositions, land level changes, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 19 to 23 February 2013 ITST covered 30 locations on 4 Islands: Ndendo (Santa Cruz), Tomotu Noi (Lord Howe), Nea Tomotu (Trevanion, Malo) and Tinakula. The reconnaissance completely circling Ndendo and Tinakula logged 240 km by small boat and additionally covered 20 km of Ndendo's hard hit western coastline by vehicle. The collected survey data includes more than 80 tsunami runup and flow depth measurements. The tsunami impact peaked at Manoputi on Ndendo's densely populated west coast with maximum tsunami height exceeding 11 m and local flow depths above ground exceeding 7 m. A fast tide-like positive amplitude of 1 m was recorded at Lata wharf inside Graciosa Bay on Ndendo Island and misleadingly reported in the media as representative tsunami height. The stark contrast between the field observations on exposed coastlines and the Lata tide gauge recording highlights the importance of rapid tsunami reconnaissance surveys. Inundation distance and damage more than 500 m inland were recorded at Lata airport on Ndendo Island. Landslides were

  20. Paleo-tsunami and storm records inferred from coastal boulders along the Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Goto, K.; Miyagi, K.; Imamura, F.

    2012-12-01

    After the 11 March 2011 Tohoku-oki earthquake and tsunami (Mw=9.0) at off the coast of Tohoku district of Japan, re-evaluation of the occurrence of large earthquake and tsunami along the subduction zone is one of the major issues in Japan. Along the Ryukyu trench, there are no known thrust type earthquakes of magnitude greater than 8.0 in the last 300 years [Ando et al., 2009, 2012], although there is one possible exception: the AD1771 event at the southern Ryukyu Islands which is characterized by the ~30 m run-up heights. Hence, the occurrence of tsunamigenic large earthquake along the Ryukyu trench in the past and future is controversial. The lack of thousands of years geological record of past earthquake and tsunami such as the sandy tsunami deposits along the Ryukyu trench has made the discussion more difficult, because there are very few suitable places to study such deposits. On the other hand, numerous coastal boulders are reported on the fringing reefs of each island [e.g. Goto et al., 2010]. They are mostly composed of the coralline and reef rocks and are regarded as useful markers of the past large tsunamis and storm events. In fact, some of them are fossil Porites sp. and hence 14C dating is possible for determining the depositional age [e.g. Araoka et al., 2010]. Moreover, boulders of tsunami and storm wave origins at Ryukyu Islands can be differentiated because difference of the wave lengths of tsunami and storm wave are affected the clast size and spatial distributions of boulders on the wide fringing reef (~1500 m) [e.g. Goto et al., 2010]. Therefore, presence or absence of tsunami boulders at each island may provide useful information of occurrence of past large tsunamis and the causative earthquakes along the Ryukyu Trench. In this study, we show the clast size and spatial distributions of more than 2,500 boulders at 11 islands along the Ryukyu trench. Based on the geological study and hydrodynamic analyses, boulders on the reefs at the Sakishima

  1. Reconnaissance Survey of the 29 September 2009 Tsunami on Tutuila Island, American Samoa

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Borrero, J. C.; Okal, E.; Synolakis, C.; Weiss, R.; Jaffe, B. E.; Lynett, P. J.; Titov, V. V.; Foteinis, S.; Chan, I.; Liu, P.

    2009-12-01

    On 29 September, 2009 a magnitude Mw 8.1 earthquake occurred 200 km southwest of American Samoa’s Capital of Pago Pago and triggered a tsunami which caused substantial damage and loss of life in Samoa, American Samoa and Tonga. The most recent estimate is that the tsunami caused 189 fatalities, including 34 in American Samoa. This is the highest tsunami death toll on US territory since the 1964 great Alaskan earthquake and tsunami. PTWC responded and issued warnings soon after the earthquake but, because the tsunami arrived within 15 minutes at many locations, was too late to trigger evacuations. Fortunately, the people of Samoa knew to go to high ground after an earthquake because of education and tsunami evacuation exercises initiated throughout the South Pacific after a similar magnitude earthquake and tsunami struck the nearby Solomon Islands in 2007. A multi-disciplinary reconnaissance survey team was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, and performance of the man-made infrastructure and impact on the natural environment. The 4 to 11 October 2009 ITST circled American Samoa’s main island Tutuila and the small nearby island of Aunu’u. The American Samoa survey data includes nearly 200 runup and flow depth measurements on Tutuila Island. The tsunami impact peaked with maximum runup exceeding 17 m at Poloa located 1.5 km northeast of Cape Taputapu marking Tutuila’s west tip. A significant variation in tsunami impact was observed on Tutuila. The tsunami runup reached 12 m at Fagasa near the center of the Tutuila’s north coast and 9 m at Tula near Cape Matatula at the east end. Pago Pago, which is near the center of the south coast, represents an unfortunate example of a village and harbor that was located for protection from storm waves but is vulnerable to tsunami waves. The flow patterns inside Pago Pago harbor were characterized based on

  2. Spatial Distribution and Sedimentary Facies of the 2007 Solomon Islands Tsunami Deposits

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Nishimura, Y.; Woodward, S.

    2007-12-01

    We conducted a field survey of the extent of damage, crustal deformation, and onshore deposits caused by 2007 Solomon Islands tsunami in Ghizo and adjacent islands in the western Solomon Islands, from 13th to 18th April, 2007. Our survey team was comprised of six Japanese and one American researcher. Three of us, the authors, mainly investigated tsunami deposits in three villages (Titiana, Suva, and Pailongge) in southern Ghizo Island. One member of our team re-investigated the deposits in June 2007. The tsunami generated sheet-like deposits of coral beach sand on the flat plain in Titiana. Beside the sea coast, the tsunami wave eroded ground surfaces and formed small scarps at 30 m from the sea. Just interior of the scarps, tsunami deposits accumulated up to 9 cm in thickness. The thickness decreased with distance from the sea and was also affected by microtopography. No sandy tsunami deposits were observed on the inland area between 170 m and 210 m from the sea. The upper boundary of inundation was recognized at about 210 m from the sea because of accumulation of driftwood and floating debris. In Suva and Pailongge, the outline of sand-sheet distribution is the same as it in Titiana. The tsunami had a maximum thickness of 10 cm and two or three sand layers are separated by thin humic sand layers. These humic layers were likely supplied from hillslopes eroded by the tsunami and transported by return-flows. These successions of deposits suggest that tsunami waves inundated at least two times. This is consistent with the number of large waves told by eyewitnesses. In the Solomon Islands, the plentiful rainfall causes erosion and resedimentation of tsunami deposits. Furthermore, the sedimentary structures will be destroyed by chemical weathering in warm and moist environment, and bioturbation by plants, animals, and human activities. The sedimentary structures had been preserved till the end of June 2007, but had already been penetrated by plant roots and sandpipes

  3. Marshall Islands Fringing Reef and Atoll Lagoon Observations of the Tohoku Tsunami

    NASA Astrophysics Data System (ADS)

    Ford, Murray; Becker, Janet M.; Merrifield, Mark A.; Song, Y. Tony

    2014-12-01

    The magnitude 9.0 Tohoku earthquake on 11 March 2011 generated a tsunami which caused significant impacts throughout the Pacific Ocean. A description of the tsunami within the lagoons and on the surrounding fringing reefs of two mid-ocean atoll islands is presented using bottom pressure observations from the Majuro and Kwajalein atolls in the Marshall Islands, supplemented by tide gauge data in the lagoons and by numerical model simulations in the deep ocean. Although the initial wave arrival was not captured by the pressure sensors, subsequent oscillations on the reef face resemble the deep ocean tsunami signal simulated by two numerical models, suggesting that the tsunami amplitudes over the atoll outer reefs are similar to that in deep water. In contrast, tsunami oscillations in the lagoon are more energetic and long lasting than observed on the reefs or modelled in the deep ocean. The tsunami energy in the Majuro lagoon exhibits persistent peaks in the 30 and 60 min period bands that suggest the excitation of closed and open basin normal modes, while energy in the Kwajalein lagoon spans a broader range of frequencies with weaker, multiple peaks than observed at Majuro, which may be associated with the tsunami behavior within the more irregular geometry of the Kwajalein lagoon. The propagation of the tsunami across the reef flats is shown to be tidally dependent, with amplitudes increasing/decreasing shoreward at high/low tide. The impact of the tsunami on the Marshall Islands was reduced due to the coincidence of peak wave amplitudes with low tide; however, the observed wave amplitudes, particularly in the atoll lagoon, would have led to inundation at different tidal phases.

  4. Discovery Of Pre-2004 Tsunami Deposits On Simeulue Island, Southern Aceh Province, Indonesia

    NASA Astrophysics Data System (ADS)

    Fujino, S.; Sieh, K.; Meltzner, A. J.; Yulianto, E.; Whitlow, K.; Putra, A.; Satake, K.

    2007-12-01

    Presumably, megathrust earthquakes and tsunamis occurred repeatedly along the Sunda megathrust before 2004 and 2005. To determine its past tsunami history, we conducted field surveys on Simeulue Island, which straddles the boundary of the 2004 and 2005 ruptures. Shallow excavations exposed paleo-tsunami deposits at two coastal lowland sites in southern Simeulue Island. The paleo-tsunami deposits at the Inor-Naibos and Busong Bay sites appear as laterally continuous sand layers in terrestrial sedimentary successions. Two paleo-tsunami layers exist at Busong Bay; the younger one is bounded by peat layers and the older one separates peat and underlying muddy sediment that was probably deposited in an inter-tidal or sub-tidal environment. Both tsunami deposits are rich in coral clasts. A fresh, uneroded coral boulder from the upper tsunami layer yielded a U/Th age that is consistent with emplacement in 1861, the year of an historical great (M-8.5) earthquake there. The lower tsunami layer may have been emplaced during an earlier uplift event around A.D. 1799, documented by an uplifted coral microatoll at the site. This interpretation is consistent with the sedimentary facies change from mud to peat across the lower tsunami layer, which probably represents an environmental change due to uplift. The single tsunami layer at the Inor-Naibos site demarcates a sedimentary facies change. As at Busong Bay, it is accompanied by coral boulders, which we think are likely to yield U/Th ages consistent with deposition contemporaneous with one of the layers at Busong Bay.

  5. Use of a Pre-Computed Data Base of Tsunami Simulations for Rapid Estimation of Tsunami Amplitude: Application to the Effective Tsunami Warning of the Great Tsunami of 11 March 2011 IN French Polynesia

    NASA Astrophysics Data System (ADS)

    Reymond, D.; Hebert, H.; Okal, E.

    2011-12-01

    We developed a method giving a rapid and accurate estimation of the tsunami amplitude based on a pre-computed database of numerical simulations; this methodology has been applied in real-time in an operational context during the March 2011 Honshu tsunami alert in French Polynesia. For this purpose we constructed a pre-computed database of numerical simulations of tsunamis for 260 scenarios, involving 20 source regions distributed in the main dangerous circum Pacific subduction zones. For each region, we consider 3 types of generic sources defined by their seismic moment and their sources dimensions: MEGA (corresponding to a scalar moment Mo of 1023 N.m), BIG (Mo = 1022 N.m) and AVERAGE (Mo = 1021 N.m). All the pre-computed scenarios give the maximum height of the sea surface in deep ocean with a time step of 1 hour. The database also includes all the synthetic waveforms (14 820) at 57 virtual receivers, including all existing DART buoys, thus allowing comparisons between calculated and observed data. The latter can help to detect abnormal earthquakes (e.g., "tsunami earthquakes", generating a larger tsunami than expected, or conversely, a "snappy" earthquake generating a deficient tsunami. The distribution of tsunami heights along a coastline is then calculated from the deep ocean sea surface using Green's law and stopping the computation at a depth of 5 m. A modified formulation of Green's law has been introduced to take into account large amplification effects of some bays in the Marquesas Islands. This method gives good results in agreement with the measures and observations made during the post tsunami field surveys of the events of Chile February 2010 and Japan March 2011

  6. Late Holocene coastal stratigraphy of Sitkinak Island reveals Aleutian-Alaska megathrust earthquakes and tsunamis southwest of Kodiak Island

    NASA Astrophysics Data System (ADS)

    Nelson, A. R.; Briggs, R. W.; Kemp, A.; Haeussler, P. J.; Engelhart, S. E.; Dura, T.; Angster, S. J.; Bradley, L.

    2012-12-01

    Uncertainty in earthquake and tsunami prehistory of the Aleutian-Alaska megathrust westward of central Kodiak Island limit assessments of southern Alaska's earthquake hazard and forecasts of potentially damaging tsunamis along much of North America's west coast. Sitkinak Island, one of the Trinity Islands off the southwest tip of Kodiak Island, lies at the western end of the rupture zone of the 1964 Mw9.2 earthquake. Plafker reports that a rancher on the north coast of Sitkinak Island observed ~0.6 m of shoreline uplift immediately following the 1964 earthquake, and the island is now subsiding at about 3 mm/yr (PBO GPS). Although a high tsunami in 1788 caused the relocation of the first Russian settlement on southwestern Kodiak Island, the eastern extent of the megathrust rupture accompanying the tsunami is uncertain. Interpretation of GPS observations from the Shumagin Islands, 380 km southwest of Kodiak Island, suggests an entirely to partially creeping megathrust in that region. Here we report the first stratigraphic evidence of tsunami inundation and land-level change during prehistoric earthquakes west of central Kodiak Island. Beneath tidal and freshwater marshes around a lagoon on the south coast of Sitkinak Island, 27 cores and tidal outcrops reveal the deposits of four to six tsunamis in 2200 years and two to four abrupt changes in lithology that may correspond with coseismic uplift and subsidence over the past millennia. A 2- to 45-mm-thick bed of clean to peaty sand in sequences of tidal sediment and freshwater peat, identified in more than one-half the cores as far inland as 1.5 km, was probably deposited by the 1788 tsunami. A 14C age on Scirpus seeds, double 137Cs peaks at 2 cm and 7 cm depths (Chernobyl and 1963?), a consistent decline in 210Pb values, and our assumption of an exponential compaction rate for freshwater peat, point to a late 18th century age for the sand bed. Initial 14C ages suggest that two similar extensive sandy beds, identified

  7. Significant Tsunami Events

    NASA Astrophysics Data System (ADS)

    Dunbar, P. K.; Furtney, M.; McLean, S. J.; Sweeney, A. D.

    2014-12-01

    Tsunamis have inflicted death and destruction on the coastlines of the world throughout history. The occurrence of tsunamis and the resulting effects have been collected and studied as far back as the second millennium B.C. The knowledge gained from cataloging and examining these events has led to significant changes in our understanding of tsunamis, tsunami sources, and methods to mitigate the effects of tsunamis. The most significant, not surprisingly, are often the most devastating, such as the 2011 Tohoku, Japan earthquake and tsunami. The goal of this poster is to give a brief overview of the occurrence of tsunamis and then focus specifically on several significant tsunamis. There are various criteria to determine the most significant tsunamis: the number of deaths, amount of damage, maximum runup height, had a major impact on tsunami science or policy, etc. As a result, descriptions will include some of the most costly (2011 Tohoku, Japan), the most deadly (2004 Sumatra, 1883 Krakatau), and the highest runup ever observed (1958 Lituya Bay, Alaska). The discovery of the Cascadia subduction zone as the source of the 1700 Japanese "Orphan" tsunami and a future tsunami threat to the U.S. northwest coast, contributed to the decision to form the U.S. National Tsunami Hazard Mitigation Program. The great Lisbon earthquake of 1755 marked the beginning of the modern era of seismology. Knowledge gained from the 1964 Alaska earthquake and tsunami helped confirm the theory of plate tectonics. The 1946 Alaska, 1952 Kuril Islands, 1960 Chile, 1964 Alaska, and the 2004 Banda Aceh, tsunamis all resulted in warning centers or systems being established.The data descriptions on this poster were extracted from NOAA's National Geophysical Data Center (NGDC) global historical tsunami database. Additional information about these tsunamis, as well as water level data can be found by accessing the NGDC website www.ngdc.noaa.gov/hazard/

  8. Source of the 6 February 2013 Mw 8.0 Santa Cruz Islands Tsunami.

    NASA Astrophysics Data System (ADS)

    Romano, F.; Molinari, I.; Lorito, S.; Piatanesi, A.

    2014-12-01

    On February 6, 2013 a Mw8.0 interplate earthquake occurred in the Santa Cruz Islands region. The epicenter is located near a complex section of the Australia-Pacific plate boundary, where a short segment of dominantly strike-slip plate motion links the Solomon Trench to the New Hebrides Trench. In this region, the Australia plate subducts beneath the Pacific plate with a convergence rate of ~9cm/yr. This earthquake generated a tsunami that struck the city of Lata and several villages located on the Nendo island with tsunami height exceeding 11m (Fritz et al.,2014). The tsunami has been distinctly recorded by 5 DART buoys in the Pacific Ocean and by some tide-gauges at Solomon Islands, Fiji Islands, and New Caledonia. In this work we retrieve the source of the tsunami by inverting the signals recorded by both DART buoys and tide-gauges, and using an earthquake fault model that accounts for the variability of the subduction plate geometry. We compare and discuss our tsunamigenic slip model with previous coseismic slip models obtained by teleseismic data (Hayes et al.,2013) and telesismic data constrained by tsunami records (Lay et al.,2013). Our preferred tsunami source (maximum slip value of ~10m) is located southeast from the hypocenter and the slip direction is in agreement with the convergence direction that becomes progressively more oblique in the NW segment. We find a tsunami source roughly consistent to a possible source of low frequency radiation (http://www.iris.edu/spud/backprojection) and/or to the region of aseismic slip argued by Hayes et al. (2013). However, we do not find significantly tsunamigenic slip in the region of seismic high frequency radiation around the hypocenter.

  9. Geomorphology and accommodation space as limiting factors on tsunami deposition: Chatham Island, southwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Nichol, S. L.; Chagué-Goff, C.; Goff, J. R.; Horrocks, M.; McFadgen, B. G.; Strotz, L. C.

    2010-07-01

    Chatham Island in the southwest Pacific Ocean is exposed on all sides to potential tsunami impact. In historical time, tsunamis are known to have inundated the coast on several occasions, with the largest event in 1868. Coastal dunes along the northeast coast of Chatham Island preserve sedimentary evidence of this and possibly earlier tsunami events, as localised gravel lags. However, these deposits lack a clear stratigraphic context and establishing their age is difficult. This study examines the sediment record in a freshwater wetland at Okawa Point, located directly landward of the dunes where apparent tsunami gravels occur. Sediment descriptions, pollen, foraminifera, chemical data and radiocarbon dates from cores are used to reconstruct the environmental history of the wetland. The record extends from ca. > 43 ka to the present and incorporates glacial, post-glacial and human-influenced phases. Throughout this time the wetland appears to have remained isolated from catastrophic marine inundation. The only evidence for saltwater intrusion is observed in the historic period, via geochemical, grain size and pollen data, which record a marine inundation event that forced the transport of a thin (cm-thick) deposit of dune and beach sand into the seaward edge of the wetland. This is interpreted as the signature of the 1868 tsunami. The lack of more widespread physical evidence for this and other tsunami events in the wetland is attributed to the morphological roughness afforded by coastal dunes and limited accommodation space for Holocene deposits.

  10. Tsunami deposits at high altitudes on the flanks of volcanic islands

    NASA Astrophysics Data System (ADS)

    Paris, Raphael

    2016-04-01

    It is actually difficult to infer the mechanisms and dynamics of giant mass failures of oceanic shield volcanoes and to evaluate related tsunami hazards. Marine conglomerates and gravels found at unusually high elevations in Hawaii, Cape Verde, Mauritius and Canary Islands are often interpreted as being the result of tsunami waves generated by such massive flank failures. In the first part of this contribution, we document tsunami deposits (marine gravels with pumices) attached to the northwestern slopes of Tenerife, Canary Islands, at altitudes up to 132 m asl. Stratigraphy of the deposits and composition of the pumices allows identifying sources of the successive tsunamis and proposing a new scenario for the Icod flank failure and El Abrigo caldera-forming eruption ca. 170 ka. Then we propose a litterature review of tsunami deposits at high altitudes on the flanks of volcanic islands, and especially oceanic shield volcanoes. These deposits are discussed in terms of texture, structure, composition and particularly the juvenile volcanic material, and implications for better understanding the mechanisms controlling massive flank failures.

  11. Tsunamis

    MedlinePlus

    ... About CDC.gov . Natural Disasters and Severe Weather Earthquakes Being Prepared Emergency Supplies Home Hazards Indoor Safety ... Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis Volcanoes ...

  12. Tsunamis

    MedlinePlus

    A tsunami is a series of huge ocean waves created by an underwater disturbance. Causes include earthquakes, landslides, volcanic eruptions, or meteorites--chunks of rock from space that strike the surface ...

  13. Tsunamis

    MedlinePlus

    ... Us Social Media Contact Us FAQS Publications Emergency Alerts Home Search × Close Search Enter Search Term(s): Languages × ... you receive a tsunami (pronounced soo-ná-mees) alert from the National Weather Service for your local ...

  14. REWSET: A prototype seismic and tsunami early warning system in Rhodes island, Greece

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Gerasimos; Argyris, Ilias; Aggelou, Savvas; Karastathis, Vasilis

    2014-05-01

    Tsunami warning in near-field conditions is a critical issue in the Mediterranean Sea since the most important tsunami sources are situated within tsunami wave travel times starting from about five minutes. The project NEARTOWARN (2012-2013) supported by the EU-DG ECHO contributed substantially to the development of new tools for the near-field tsunami early warning in the Mediterranean. One of the main achievements is the development of a local warning system in the test-site of Rhodes island (Rhodes Early Warning System for Earthquakes and Tsunamis - REWSET). The system is composed by three main subsystems: (1) a network of eight seismic early warning devices installed in four different localities of the island, one in the civil protection, another in the Fire Brigade and another two in municipality buildings; (2) two radar-type (ultrasonic) tide-gauges installed in the eastern coastal zine of the island which was selected since research on the historical earthquake and tsunami activity has indicated that the most important, near-field tsunami sources are situated offshore to the east of Rhodes; (3) a crisis Geographic Management System (GMS), which is a web-based and GIS-based application incorporating a variety of thematic maps and other information types. The seismic early warning devices activate by strong (magnitude around 6 or more) earthquakes occurring at distances up to about 100 km from Rhodes, thus providing immediate mobilization of the civil protection. The tide-gauges transmit sea level data, while during the crisis the GMS supports decisions to be made by civil protection. In the near future it is planned the REWSET system to be integrated with national and international systems. REWSET is a prototype which certainly could be developed in other coastal areas of the Mediterranean and beyond.

  15. Psychological Impact of the Tsunami on Children and Adolescents From the Andaman and Nicobar Islands

    PubMed Central

    Math, Suresh Bada; Tandon, Shweta; Girimaji, Satish Chandra; Benegal, Vivek; Kumar, Uday; Hamza, Ameer; Jangam, Kavita; Nagaraja, D.

    2008-01-01

    Objective: The aim of this article is to present the assessment of the presentation of symptoms and psychiatric morbidity of children and adolescents from the Andaman and Nicobar islands during the first 3 months following the December 2004 earthquake and tsunami. Method: According to predefined criteria, a primary survivor is one who was exposed directly to the earthquake and tsunami, a secondary survivor is one with close family and personal ties to primary survivors, and tertiary survivors are individuals from the communities beyond the impact area, a majority of which were exposed to the earthquake only. This study included 37 primary and secondary survivors (aged ≤ 18 years) and 498 tertiary survivors of the tsunami disaster. Tertiary survivors were recruited from the 10th and 12th grades of schools in Port Blair, India. The following 3 screening and treatment methods were adopted: (1) mental health clinic, (2) art therapy, and (3) group discussions. Results: The most common psychiatric morbidities observed among the primary and secondary survivors were adjustment disorder (N = 5, 13.5%), depression (N = 5, 13.5%), panic disorder (N = 4, 10.8%), posttraumatic stress disorder (N = 4, 10.8%), schizophrenia (N = 1, 2.7), and other disorders (N = 16, 43.2%). Subclinical syndrome was present in the majority of the primary and secondary survivors. Few tertiary survivors had subsyndromal symptoms. Conclusion: Only a few of the primary and secondary survivors required intensive individual psychiatric interventions; however, a majority of the primary, secondary, and tertiary survivors required community-based group interventions. Community-based group interventions and group discussions are simple, easy to implement using local resources, and effective in all groups, and provide important components of psychosocial rehabilitation. This kind of approach should be started as early as possible, targeting all children and adolescents affected by any disaster in

  16. Applying and validating the PTVA-3 Model at the Aeolian Islands, Italy: assessment of the vulnerability of buildings to tsunami

    NASA Astrophysics Data System (ADS)

    Dall'Osso, Filippo; Maramai, Alessandra; Graziani, Laura; Brizuela, Beatriz; Cavalletti, Alessandra; Gonella, Marco; Tinti, Stefano

    2010-05-01

    one structure, whose seaward side is completely submerged by a coastal dune, we found a good degree of accuracy of the model. Given the high tsunami risk of the archipelago, our results provide a basic support to prioritize investments in prevention measures and address the most critical vulnerabilities of built environment, particularly in the island of Stromboli. Dall'Osso, F., Gonella, M., Gabbianelli, G., Withycombe, G., and Dominey-Howes, D.: "A revised (PTVA) model for assessing the vulnerability of buildings to tsunami damage", Nat. Hazards Earth Syst. Sci., 9, 1557-1565, 2009 Maramai, A., Graziani, L., Tinti, S.: "Tsunamis in the Aeolian islands (southern Italy): a review", Marine Geology, 215, 11-21, 2005. Papathoma, M., Dominey-Howes, D., Zong, Y., Smith, D.: "Assessing Tsunami vulnerability, an example from Herakleio, Crete", Natural Hazards and Earth System Sciences, 3, 377-389, 2003. Tinti S., Maramai A., Armigliato A., Graziani L., Manucci A., Pagnoni G., Zaniboni F.:"Observations of physical effects from tsunamis of december 20, 2002 at Stromboli volcano, southern Italy", Bulletin of Volcanology 68, 450-461, 2005.

  17. The 2004 Indian Ocean Tsunami in Maldives: waves and disaster affected by shape of coral reefs and islands

    NASA Astrophysics Data System (ADS)

    Kan, H.; Ali, M.; Riyaz, M.

    2005-12-01

    In Maldives, 39 islands are significantly damaged among 200 inhabited islands and nearly a third of the Maldivian people are severely affected by the Indian Ocean Tsunami in 26 December 2004. We surveyed tsunami impact in 43 islands by measuring island topography and run-up height, interview to local people and mapping of the flooded and destructed areas. The differences in tsunami height and disaster corresponding to the atoll shape and island topography are observed. In the northern atolls, atoll rims consist of many ring-shaped reefs, i.e. miniature atolls called `faro', and interrupted many channels between them. The interrupted atoll rim may play an important role to reducing tsunami run-up height. Severe damage was not observed in the eastern coast of the islands. Beach ridge also contribute to the protection against tsunami. However, in some islands, houses beside the lagoon are damaged by backwashing floodwater from the lagoon. Water marks show the run-up height of -1.8m above MSL. The lagoon water-level seems to set-up by tsunami which permeates into the lagoon through the interrupted atoll rim. The disaster was severe at the southern atolls of Meemu, Thaa and Laamu. The higher run-up heights of up to 3.2m above MSL and enormous building damages were observed at the islands on the eastern atoll rims. The continuous atoll rim of these atolls may reinforce tsunami impact at the eastern islands. In addition, tsunami surge washed the islands totally because of low island topography without beach ridge. Significant floodwater from lagoon was not observed in these atolls. It seems the lagoon water-level was not set-up largely. The continuous atoll rim reduces the tsunami influence to the lagoon and the western side of the atolls. The continuity of atoll rim is probably the major factor to cause the difference in water movement, i.e. tsunami run-up and lagoon set-up, which affects the disaster in the islands. Beach ridge contribute to reduce the tsunami impact to

  18. The Role of Corals on Tsunami Dynamics in an Island Setting: A Case Study of Tutuila Island

    NASA Astrophysics Data System (ADS)

    Dilmen, Derya Itir

    On September 29, 2009 at 17:48 UTC, an Mw = 8.1 earthquake in the Tonga Trench generated a tsunami that caused heavy damage across Samoa, American Samoa, and Tonga. One of the worst localities hit was the volcanic island of Tutuila in American Samoa. Tutuila Island, located 250 km from earthquake epicenter, experienced tsunami inundation and strong currents on the north and east coasts, causing 34 fatalities and widespread structural and ecological damage. The surrounding coral reefs of the island also suffered heavy damage. This damage was formally evaluated based on detailed surveys before and immediately after the tsunami, which provides a unique opportunity to evaluate the role of coral reefs on tsunami dynamics. In the first part of this research, estimates of tsunami dynamics are obtained with the MOST numerical tsunami model (Titov and Synolakis, 1997), which is currently the operational tsunami forecast tool used by the US National Oceanic and Atmospheric Administration (NOAA). The earthquake source function was constrained using real-time deep-ocean tsunami data from three DARTRTM (Deep-ocean Assessment and Reporting for Tsunamis) systems in the far field, and by tide-gauge observations in the near field. We compare the numerically estimated run-up with observations to evaluate the simulation skill of MOST. We present an overall synthesis of tide-gage data, survey results of the run up, inundation measurements, and the datasets of coral damage around the island, in order to evaluate the overall accuracy of MOST run-up prediction for Tutuila and the model's performance of simulating in the locations covered with corals during the tsunami event. Our primary findings are 1) there is a tendency for MOST to underestimate run-up on Tutuila and 2) the locations where the model underestimates run-up tend to have experienced heavy or very heavy coral damage, whereas well-estimated run-up locations characteristically experienced low or very low damage. This brought

  19. Tsunami preparedness at the resort facilities along the coast of the Ryukyu Islands - their actions against the 27 February 2010 Okinawan and Chilean tsunami warning

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.

    2010-12-01

    The economy (including tourism) in tropical and subtropical coastal areas, such as Okinawa Prefecture (Ryukyu) is highly relying on the sea. The sea has both “gentle” side to give people healing and “fierce” 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 the whole nature of the sea, Tsunami is the typical case of the “fierce” side of the sea. We have already learned a lesson about this issue from the Sumatra tsunami in 2004. Early morning (5:31 am Japanese Standard Time = JST) on 27 February 2010, a M6.9 earthquake occurred near the coast of Okinawa Ryukyu Island Japan, and just after that Japanese Meteorological Agency (JMA) issued a tsunami warning along the coastal area of Okinawa Prefecture. About one hour later the tsunami warning was cancelled. The CMT solution of this earthquake was found to be strike-slip type with NE-SW P-axis. Therefore this did not induce a tsunami. However, in the afternoon on the same day (JST) a M8.6 earthquake occurred off the coast of Chile and soon after that a tsunami warning issued along the Pacific coastal area including Japan and Ryukyu Islands. Indeed maximum 1m tsunami hit the eastern coast of Okinawa Island on 28th February (Nakamura, 2010, personal communication). The author conducted a survey about the actions against the both tsunami after the 27 February tsunami warming to the major resort hotels along the coast of the Ryukyu Islands. A questionnaire was sent to about 20 hotels and 6 hotels replied to the questionnaire. Most of these hotels reported the regular training against tsunami attack, preparation of a disaster prevention manual, close communication with the local fire station authority, evacuation procedure towards high stories of the hotel building etc. It was “winter season” when the tsunami took place. However, if that were “summer season,” the other problem such as how they make the people

  20. Physical Modeling of Tsunamis Generated By 3D Deformable Landslides in Various Scenarios From Fjords to Conical Islands

    NASA Astrophysics Data System (ADS)

    McFall, B. C.; Fritz, H. M.

    2013-12-01

    Tsunamis generated by landslides and volcano flank collapse can be particularly devastative in the near field region due to locally high wave amplitudes and runup. The events of 1958 Lituya Bay, 1963 Vajont reservoir, 1980 Spirit Lake, 2002 Stromboli and 2010 Haiti demonstrate the danger of tsunamis generated by landslides or volcano flank collapses. Unfortunately critical field data from these events is lacking. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. Two different materials are used to simulate landslides to study the granulometry effects: naturally rounded river gravel and cobble mixtures. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by means of four pneumatic pistons down a 2H:1V slope. The landslide is launched from the sliding box and continues to accelerate by gravitational forces up to velocities of 5 m/s. The landslide Froude number at impact with the water is in the range 1 island setting representing a landslide off an island or a volcano flank collapse. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified with video image processing. The measured landslide and wave parameters are

  1. Can Small Islands Protect Nearby Coasts From Tsunamis? An Active Experimental Design Approach

    NASA Astrophysics Data System (ADS)

    Stefanakis, Themistoklis; Contal, Emile; Vayatis, Nicolas; Dias, Frédéric; Synolakis, Costas

    2013-04-01

    In recent years we have witnessed the dreadful damage tsunamis caused in coastal areas around the globe. In some of these locations, small islands in the vicinity of the mainland offer protection from wind-generated waves and thus communities were developed. But do these islands act as natural barriers to tsunamis? Recent post-tsunami survey data reveal that in certain cases the run-up in coastal areas behind small offshore islands was significantly higher than in neighboring locations. To study the conditions of this run-up amplification, we solve numerically the nonlinear shallow water equations. We use the simplified geometry of a conical island sitting on a flat bed in front of a uniform sloping beach. Hence, the experimental setup is controlled by five physical parameters, namely the island slope, the beach slope, the water depth, the distance between the island and the plane beach and the incoming wavelength, while the wave height was kept fixed. An active experimental design approach was adopted in order to find with the least number of simulations the maximum run-up amplification on the area of the beach behind the island with respect to a lateral location on the beach, not directly affected by the presence of the island. For this purpose, a statistical emulator was built to guide the selection of the query points in the input space and a stopping criterion was used to signal when no further simulations were needed. We have found that in all cases explored, the run-up amplification was larger than unity and in certain occasions reached up to 70% increase. The presence of the island delays the run-up of the wave on the plane beach behind it, while edge waves generated by the run-up in lateral locations on the beach converge towards the center. The synchronous arrival of the three waves (2 edge waves and tsunami from the lee side of the island) is responsible for the run-up amplification in these areas. The use of the active experimental design approach can

  2. Geologic Survey of the 2 April 2007 Solomon Islands Earthquake and Tsunami

    NASA Astrophysics Data System (ADS)

    Rafiau, W. B.; Jackson, K. L.; Billy, D.; Bonte-Grapentin, M.; Kruger, J.; McAdoo, B. G.; Moore, A. L.; Tiano, B.

    2007-12-01

    The 2 April 2007 magnitude 8.1 Solomon Islands earthquake and tsunami caused extensive damage to coral reefs, coastal erosion, and in some locations, 3 meters of uplift, subsidence, and numerous landslides in the Western and Choiseul Provinces. Extensive damage to the coral reefs ranged from shattered branching corals to 4 meter head corals snapped off their bases and toppled over. The fringing reef on the east coast of Ranongga sustained the greatest degree of damage as it was uplifted 3 m above sea level and remains completely exposed. Sediment samples were collected along transects extended from offshore to onshore environments for larger islands, such as Ghizo, where the tsunami did not pass over the entire island. Smaller islands, such as Nusa Aghana, a transect was conducted from the outer barrier reefs, through the lagoon, across the island, and offshore on the opposing side of the island. Offshore data was collected using a side-scan sonar system that records bathymetry and images coral reef morphology. This data was coupled with snorkeling and SCUBA diving to ground truth the offshore lagoon and reef environments. Sediment samples were collected offshore every 5 m and were documented by underwater photos and GPS coordinates. Offshore to onshore sediment transects reveal that sediment was eroded from seaward facing shorelines, deposited a thin veneer of sediment on islands, and transported the majority of the sediment on coral reefs on the lagoon side of islands, essentially burying coral and lagoonal sediment. Coral reef damaged by the earthquake and tsunami represents a major concern for an already threatened ecosystem. Recovery of the fishing and dive tourism economies rely on the healthy reestablishment of the reef.

  3. Tsunami recurrence inferred from soil deposits on Ishigaki island along the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Ando, M.; Shishikura, M.; Tu, Y.; Nakamura, M.; Arashiro, Y.

    2012-12-01

    The Ryukyu trench at the northwestern boundary of the Philippine Sea plate had no known thrust earthquakes Mw>8.0 in approximately the last 250 years. Due to this lack of associated large thrust earthquakes, an accepted common idea is that Ryukyu trench is aseismic. However, in 1771 a large tsunami struck Ishigaki islands and Miyako islands with the run-up height of up to 30-35 m. The 1771 source is suggested to be a tsunami (slow) earthquake with Mw=8.0 that occurred near the trench axis. Furthermore, very-low frequency earthquakes at shallow depths near the trench axis and slow-slip events at depths of 30km have been identified in the western Ryukyu trench. These findings suggest that the Ryukyu subduction zone has the potential to generate large thrust earthquakes. If the slip deficit has accumulated at the interface, the accumulated slip of more than 30 m would cause a large earthquake and a huge tsunami. Considering the abovementioned findings, estimate for the size and recurrence intervals of past tsunamis along the western Ryukyu trench was undertaken through excavation surveys of the Holocene deposits in Ishigaki and Miyako islands. The excavated sites are located on the lower Holocene marine terraces and implemented using a geoslicer or backhoes at 10 sites on November 2011 and June 2012. Stratigraphic and foraminiferal assemblages of tsunami sediment were compared with shallow beach sand to gain information on sediment source and depositional style. Based on the excavations, two tsunami layers were identified at 5 sites and provided estimates of sedimentation ages. The results obtained from stratigaraphic and foraminiferal analyses together with C14 dates of tsunami sediment indicated an event between 9-11th C. on Ishigaki and another or the same event occurred between 11th C. and 1771 on Miyako island. Consequently, if the 1771 earthquake is the only event that had occurred in the last 300 years over the 120 km, large earthquakes would potentially occur

  4. 3D numerical investigation on landslide generated tsunamis around a conical island

    NASA Astrophysics Data System (ADS)

    Montagna, Francesca; Bellotti, Giorgio

    2010-05-01

    This paper presents numerical computations of tsunamis generated by subaerial and submerged landslides falling along the flank of a conical island. The study is inspired by the tsunamis that on 30th December 2002 attacked the coast of the volcanic island of Stromboli (South Tyrrhenian sea, Italy). In particular this paper analyzes the important feature of the lateral spreading of landside generated tsunamis and the associated flooding hazard. The numerical model used in this study is the full three dimensional commercial code FLOW-3D. The model has already been successfully used (Choi et al., 2007; 2008; Chopakatla et al, 2008) to study the interaction of waves and structures. In the simulations carried out in this work a particular feature of the code has been employed: the GMO (General Moving Object) algorithm. It allows to reproduce the interaction between moving objects, as a landslide, and the water. FLOW-3D has been firstly validated using available 3D experiments reproducing tsunamis generated by landslides at the flank of a conical island. The experiments have been carried out in the LIC laboratory of the Polytechnic of Bari, Italy (Di Risio et al., 2009). Numerical and experimental time series of run-up and sea level recorded at gauges located at the flanks of the island and offshore have been successfully compared. This analysis shows that the model can accurately represent the generation, the propagation and the inundation of landslide generated tsunamis and suggests the use of the numerical model as a tool for preparing inundation maps. At the conference we will present the validation of the model and parametric analyses aimed to investigate how wave properties depend on the landslide kinematic and on further parameters such as the landslide volume and shape, as well as the radius of the island. The expected final results of the research are precomputed inundation maps that depend on the characteristics of the landslide and of the island. Finally we

  5. Effects of the 29 September 2009 tsunami on the Western Samoan coasts

    NASA Astrophysics Data System (ADS)

    Brizuela, Beatriz; Pagnoni, Gianluca; Tonini, Roberto

    2010-05-01

    The Samoa islands are located between 169.5°W to 172.9°W and at about 14°S. The main islands are Savaii, Upolu and Tutuila. The islands lay on the Pacific Plate, are of volcanic origin, rise sharply from the seafloor from depths of about 4000 m and are surrounded by smaller islands that are usually coral atolls. Upolu and Savaii are part of the Western Samoa while the Tutuila Island is an American territory. A regional tsunami was triggered on September the 29th 2009 by an offshore earthquake with Mw=8.1 and epicentre located at about 190 km south of Samoa, near the subduction zone between the Pacific and the Australian Plate. The tsunami waves struck severely the islands of Upolu, Manono and Savaii in Western Samoa, and their effects were also observed in Tutuila, Niuatoputapu in northern Tonga, Wallis and Funtuna. A few weeks after the event, a post tsunami field survey was organised by the UNESCO with the cooperation of the University of South Pacific and The Australian Tsunami Research Centre. The field survey had several tasks, including building damage assessment and measurement of tsunami run-ups and inundation along the Western Samoa coast. In this work, measured values of run-up and inundation along some land profiles are shown. The values vary from 0.7 to 6.5 meters, being the most affected zone the south east coast. The measurements have been taken using levelling procedures performed by the UNIBO-INGV team. Damage building assessment was also performed by the team, retrieving information of some structures such as type of material used, age of the structure, degree of exposure to the waves, content of damage and water depth when there were watermarks available.

  6. Coastal Sedimentation Associated with the Tohoku Tsunami of 11 March 2011 in South Kuril Islands, NW Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Ivanova, E. D.; Kharlamov, A. A.; Kaistrenko, V. M.; Shishkin, A. A.

    2013-06-01

    Sediment deposited by the Tohoku tsunami of March 11, 2011 in the Southern Kurils (Kunashir, Shikotan, Zeleniy, Yuri, Tanfiliev islands) was radically different from sedimentation during local strong storms and from tsunamis with larger runup at the same location. Sediments from the 2011 Tohoku tsunami were surveyed in the field, immediately and 6 months after the event, and analyzed in the laboratory for sediment granulometry, benthos Foraminifa assemblages, and diatom algae. Run-up elevation and inundation distance were calculated from the wrackline (accumulations of driftwood, woody debris, grass, and seaweed) marking the distal edge of tsunami inundation. Run-up of the tsunami was 5 m at maximum, and 3-4 m on average. Maximum distance of inundation was recorded in river mouths (up to 630 m), but was generally in the range of 50-80 m. Although similar to the local strong storms in runup height, the tsunami generally did not erode the coast, nor leave a deposit. However, deposits uncharacteristic of tsunami, described as brown aleuropelitic (silty and clayey) mud rich in organic matter, were found in closed bays facing the South Kuril Strait. These closed bays were covered with sea ice at the time of tsunami. As the tsunami waves broke the ice, the ice floes enhanced the bottom erosion on shoals and destruction of low-lying coastal peatland even at modest ranges of runup. In the muddy tsunami deposits, silt comprised up to 64 % and clay up to 41.5 %. The Foraminifera assemblages displayed features characteristic of benthic microfauna in the near-shore zone. Deep-sea diatoms recovered from tsunami deposits in two closely situated bays, namely Krabovaya and Otradnaya bays, had different requirements for environmental temperature, suggesting these different diatoms were brought to the bays by the tsunami wave entraining various water masses when skirting the island from the north and from the south.

  7. A deep scar in the flank of Tenerife (Canary Islands): Geophysical contribution to tsunami hazard assessment

    NASA Astrophysics Data System (ADS)

    Coppo, Nicolas P.; Schnegg, Pierre-André; Falco, Pierik; Costa, Roberto

    2009-05-01

    Among the high-intensity on-Earth tsunami generating events, seismicity, submarine landslides, and volcano lateral collapses are the most important [Ward, S.H., 2001. Landslide tsunami. J. Geophy. Res. 106, 11201-11215; Holcomb, R.T., Searle, R.C., 1991. Large landslides from oceanic volcanoes. Mar. Geotech. 10, 19-32; Tinti, S., Bortolucci, E., Romagnoli, C., 2000. Computer simulations of tsunamis due to the sector collapse ar Stromboli, Italy. J. Volcano. Geotherm. Res. 96, 103-128; Ward, S.N., Day, S., 2003. Ritter Island Volcano — lateral collapse and the tsunami of 1888. Geophys. J. Int. 154, 891-902; MacGuire, W.J., 2003. Volcano instability and lateral collapse. Revista 1, 33-45]. Offshore bathymetry studies highlighted huge accumulations of large mass-waste flows (up to thousands cubic kilometres) inherited from past lateral collapses or submarine landslides [ Le Friant, A., Boudon, G., Deplus, C., Villemant, B., 2003. Large-scale flank collapse events during the activity of Montagne Pelée, Martinique, Lesser Antilles. J. Geophys. Res. 108, ECV13; Moore, J.G. et al., 1989. Prodigious submarine Landslides on the Hawaiian ridge. J. Geophys. Res. 94, 17465-17484] which spread over more than 100 km off the northern Tenerife (Canary Islands) coastline [Watts, A.B., Masson, D.G., 1995. A giant landslide on the north flank of Tenerife, Canary Islands. J. Geophys. Res. 100, 24487-24498]. Although mechanics and dynamics triggering such catastrophic events follow from combined complex processes and interactions [Hürlimann, M., Garcia-Piera, J.-O., Ledesma, A., 2000. Causes and mobility of large volcanic landslides: application to Tenerife, Canary Islands. J. Volcano. Geotherm. Res. 103, 121-134; Masson, D.G. et al., 2002. Slope failures on the flanks of the western Canary Islands. Earth-Sci. Rev. 57, 1-35; Reid, M.E., Sisson, T.W., Brien, D.L., 2001. Volcano collapse promoted by hydrothermal alteration and edifice shape, Mount Rainier, Washington. Geology 29, 779

  8. Quantification of Tsunami Bathymetry Effect on Finite Fault Slip Inversion

    NASA Astrophysics Data System (ADS)

    Bletery, Quentin; Sladen, Anthony; Delouis, Bertrand; Mattéo, Lionel

    2015-12-01

    The strong development of tsunami instrumentation in the past decade now provides observations of tsunami wave propagation in most ocean basins. This evolution has led to the wide use of tsunami data to image the complexity of earthquake sources. In particular, the 2011 Mw9.0 Tohoku-Oki earthquake is the first mega-event for which such a tsunami instrumentation network was available with an almost complete azimuthal coverage. Source inversion studies have taken advantage of these observations which add a lot of constrain on the solutions, especially in the shallow part of the fault models where other standard data sets tend to lack resolution: while on-land data are quite insensitive to slip on the often-distant shallow part of a subduction fault interface, tsunami observations are directly sensitive to the shallowest slip. And it is in this shallow portion that steep bathymetry combined with horizontal motion, the so-called bathymetry effect, can contribute to the tsunami excitation, in addition to the direct vertical sea-bottom deformation. In this study, we carefully investigate the different steps involved in the calculation of this bathymetry effect, from the initial sea-floor deformation to the prediction of the tsunami records, and evaluate its contribution across the main subduction zones of the world. We find that the bathymetry effect locally exceeds 10 % of the tsunami excitation in all subduction zones and 25 % in those known to produce the largest tsunami, either from mega- or tsunami- earthquakes. We then show how the bathymetry effect can modify the tsunami wave predictions, with time shifts of the wavefront and amplitudes sometimes varying by a factor of two. If the bathymetry effect can have a strong impact on the simulated tsunami, it will also affect the solution of the finite-fault slip inversion. We illustrate this later aspect in the case of the Tohoku-Oki earthquake. We find that not accounting for the bathymetry effect will not necessarily

  9. Spatial Heterogeneity of Holocene Tsunami Deposits As Preserved on Koh Phra Thong Island, Thailand

    NASA Astrophysics Data System (ADS)

    Kirby, M. E.; Rhodes, B. P.; Choowong, M.; Frady, W.; Leeper, R.

    2010-12-01

    Thailand’s Koh Phra Thong Island is characterized by ridge-swale topography. Unlike the ridges, swales often hold water during the wet season, which allows for the deposition and preservation of sediment. As a result, swales are potential archives for past tsunami deposits. Seven different swale sites spanning 1.9km horizontal distance were excavated to investigate the occurrence, and distribution, of paleo-tsunami deposits across the island. Five of the seven sites were trenched across the breadth of their swale to a depth that exposed the early-mid Holocene highstand beach sands; the remaining two sites were examined by pits. These seven sites are located approximately 2km north of sites previously developed by Jankaew et al. (2008) and 1km or less north of sediment probe cores taken by Fujino et al. (2009). Our results reveal a highly heterogeneous spatial distribution of probable pre-2004 A.D. tsunami event deposits with a range from one to possibly four events. At almost every site, the event deposits are characterized by sharply bordered, sandy sediment units that taper in decreasing thickness away from the seaward side of the swale. Interestingly, there is no apparent relationship between swale size (depth or width) or distance from present beach front and the number or preservation “quality” of pre-2004 deposits. Future research will examine the timing of these events in relationship to our seven sites as well as other sites (Jankaew, Fujino) across the island.

  10. Assessment of the Chile 2010 and Japan 2011 Tsunami Events in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Renteria, Willington; Lynett, Patrick

    2015-04-01

    The object of this study is to present an analysis of measurements and observations from the Chile 2010 and Japan 2011 tsunamis, in order to understand the particular response of the Galápagos Islands to the occurrence of these extreme events. There was very limited data measured in the Galápagos during the tsunami events, other than a high-frequency and continuous record of each event logged at the two tidal gauge stations. With this data, a wavelet analysis is performed with the aim of discriminating different patterns in wave periods along the record of observation and to recognize the frequency response of the islands to an incoming tsunami. During both events, a clear and persistent signal is found in the period range of ten to twelve minutes for Baltra tide gauge, and in the range of seventeen to twenty minutes for Santa Cruz tide gauge. Both of these persistent signals are speculated to be a shelf resonant mode particular to the Galápagos Islands and the Galápagos Platform.

  11. Six large tsunamis in the past ~1700 years at Stardust Bay, Sedanka Island, Alaska

    NASA Astrophysics Data System (ADS)

    Witter, R. C.; Carver, G. A.; Bender, A. M.; Briggs, R. W.; Gelfenbaum, G. R.; Koehler, R. D.

    2013-12-01

    Two great earthquakes in 1946 (Unimak Island, Mw 8.1) and 1957 (Andreanof Islands, Mw 8.6) ruptured parts of the central Alaska-Aleutian subduction zone, generating deadly pan-Pacific tsunamis that hit Hawaii. Here, we provide the first estimates of recurrence intervals of such destructive Aleutian-born tsunamis from evidence for tsunami inundation at Stardust Bay on the Pacific coast of Sedanka Island, ~25 km southeast of Dutch Harbor, Alaska. We used soil augers, outcrops and shallow pits to map 6 continuous sand deposits across four depositional environments in a ~500-m-wide, 35-hectare valley. Successive sandy deposits mantled the crests of beach ridges, buried peat formed in freshwater wetlands and upland muskeg, and accumulated to form unusual terrace remnants along the valley's inland margin. Dark, basaltic tephras interbedded in peat underlying two of the sands guided stratigraphic correlation across the study area. Thin, peaty horizons separate the six gray sand beds that can be distinguished from black tephra deposits by their compositions, which consist of subangular volcanic lithics similar to Stardust Bay beach sand. The youngest sand, often the thinnest (<1-13 cm) of the six deposits, underlies drift logs scattered across the landscape at elevations up to 18.5 m and as far as 800 m inland, which provide minimum limits on inundation for the most recent tsunami. The older sands vary in thickness from 6-50 cm and often have rounded gravel at the bases of multiple, normally-graded sand beds, some of which contain ripped-up mud or peat clasts. The sheet-like sand beds blanket topography, thinning over beach ridges and thickening in swales and bogs. Although marine foraminifera are absent in the sandy and peaty deposits in the valley, we infer a tsunami origin for the sand beds, based on their physical properties. The activity of 210Pb and 137Cs in organic-rich sediment above and below the youngest sand bed suggest it predates 1963, consistent with

  12. The Tohoku Tsunami of 11 March 2011: The Key Event to Understanding Tsunami Sedimentation on the Coasts of Closed Bays of the Lesser Kuril Islands

    NASA Astrophysics Data System (ADS)

    Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Ivanova, E. D.; Kharlamov, A. A.; Kaistrenko, V. M.; Arslanov, Kh. A.; Chernov, S. B.

    2014-12-01

    The Tohoku tsunami of 11 March 2011 manifested in the region of the South Kuril Islands, although, as a rule, the run-up heights in this region did not exceed 3 m. In closed bays that were covered with ice before the tsunami, the eroding capacity of tsunami waves was aggravated by the ice fragments they carried. Here, mud sheets formed, reaching up to 106 m inland. The 2012 studies have shown well-preserved tsunami deposits, evident 1.5 years after the event. A comparative analysis of tsunami deposits from the periphery and from the near-field area close to the tsunami source was performed; this was important for understanding the deposition mechanism during the event, as it had different strengths on different shores. The difference in run-up heights determined the considerable differences in erosion, sedimentation, distribution of tsunami deposits, the formation of sedimentary structures, grain-size composition, and diatom and foraminifera assemblages. The sources of the material also varied significantly from each other: the material came from offshore in closed bays located in the tsunami source periphery, while in the near-field region close to the epicenter, the most active erosion occurred in the inundation area. In the latter area, the main sources of sand were beaches and dunes, while soil erosion was the source of mud. Studies of the Tohoku tsunami on the coasts of the Lesser Kuril Islands demonstrated that mud layers in the sections of coastal lowlands in closed bays could contain preserved detailed geological records of paleotsunamis, even those with a small-height run-up. In the sections of coastal peatlands of closed bays on Shikotan Island, up to 7-9 layers of mud and silty sands were found, these can easily be traced for more than 500 m inland. The grain-size composition of the mud is similar to the deposits of the 2011 Tohoku tsunami. The marine origin of these deposits is confirmed by the diatom analysis data.

  13. California Tsunami Policy Working Group

    NASA Astrophysics Data System (ADS)

    Real, C. R.; Johnson, L. A.

    2012-12-01

    California has established a Tsunami Policy Working Group of specialists from government and industry, from diverse fields including tsunami, seismic, and flood hazards, local and regional planning, structural engineering, natural hazard policy, and coastal engineering that have come together to facilitate the development of policy recommendations for tsunami hazard mitigation. The group is acting on findings from two major efforts: the USGS SAFRR (Science Application for Risk Reduction) Project - Tsunami Scenario, a comprehensive impact analysis of a large credible tsunami originating from a M 9.0 earthquake on the Aleutian Islands striking California's Coastline, and the State's Tsunami Hazard Mitigation and Education Program carried out by the California Emergency Management Agency and the California Geological Survey. The latter program is currently involved with several projects to help coastal communities reduce their tsunami risk, including two pilot projects (Crescent City in Del Norte County and the City of Huntington Beach in Orange County) where tsunami risk is among the highest in California, and a third pilot study focusing on the maritime community. The pilot projects are developing and testing probabilistic tsunami hazard products that will assist land-use and construction decisions for coastal development. The role of the policy group is to identify gaps and issues in current tsunami hazard mitigation, make recommendations that will help eliminate these impediments and to provide advice that will assist in the development and implementation of effective tsunami hazard products that will help coastal communities improve tsunami resiliency.

  14. Ground penetrating radar examination of thin tsunami beds - A case study from Phra Thong Island, Thailand

    NASA Astrophysics Data System (ADS)

    Gouramanis, Chris; Switzer, Adam D.; Polivka, Peter M.; Bristow, Charles S.; Jankaew, Kruawun; Dat, Pham T.; Pile, Jeremy; Rubin, Charles M.; Yingsin, Lee; Ildefonso, Sorvigenaleon R.; Jol, Harry M.

    2015-11-01

    Coastal overwash deposits from tsunamis and storms have been identified and characterised from many coastal environments. To date, these investigations have utilised ad-hoc time, energy and cost intensive invasive techniques, such as, pits and trenches or taking core samples. Here, we present the application of high-frequency ground penetrating radar (GPR) to identify and characterise the 2004 Indian Ocean Tsunami (IOT) and palaeotsunami deposits from Phra Thong Island, Thailand. This site is one of the most intensively studied palaeotsunami sites globally and preserves a series of late-Holocene stacked sandy tsunami deposits within an organic, muddy low-energy backbeach environment. Using 100, 500 and 1000 MHz GPR antennas, 29 reflection profiles were collected from two swales (X and Y) inland of the modern beach, and two common mid-point (CMP) profiles using the 200 MHz antennas were collected from Swale Y. Detailed examination of the CMPs allowed accurate velocity estimates to be applied to each profile. The reflection profiles included across-swale profiles and a high-resolution grid in Swale X, and were collected to investigate the feasibility of GPR to image the palaeotsunami deposits, and two profiles from Swale Y where the tsunami deposits are poorly known. The 500 MHz antennas provided the best stratigraphic resolution which was independently validated from the stratigraphy and sedimentology recovered from 17 auger cores collected along the profiles. It is clear from the augers and GPR data, that the different dielectric properties of the individual layers allow the identification of the IOT and earlier tsunami deposits on Phra Thong Island. Although applied in a coastal setting here, this technique can be applied to other environments where thin sand beds are preserved, in order to prioritise sites for detailed examination.

  15. Damages in American Samoa due to the 29 September 2009 Samoa Islands Region Earthquake Tsunami

    NASA Astrophysics Data System (ADS)

    Okumura, Y.; Takahashi, T.; Suzuki, S.

    2009-12-01

    A large earthquake of Mw 8.0 occurred in Samoa Islands Region in the early morning on 29 September 2009 (local time). A Large Tsunami generated by the earthquake hit Samoa, American Samoa, Tonga. Total 192 people were died or missing in these three countries (22 October 2009). The authors surveyed in Tutuila Island, American Samoa from 6 to 8 in October 2009 with the aim to find out damages in the disaster. In American Samoa, death and missing toll was 35. The main findings are as follows; first, human damages were little for tsunami run-up height of about 4 to 6 meters and tsunami arrival time of about 20 minutes. We can suppose that residents evacuated quickly after feeling shaking or something. Secondly, houses were severely damaged in some low elevation coastal villages such as Amanave, Leone, Pago Pago, Tula and so on. Third, a power plant and an airport, which are important infrastructures in relief and recovery phase, were also severely damaged. Inundation depth at the power plant was 2.31 meters. A blackout in the daytime lasted when we surveyed. On the other hand, the airport could use already at that time. But it was closed on the first day in the disaster because of a lot of disaster debris on the runway carried by tsunami. Inundation depth at the airport fence was measured in 0.7 to 0.8 meters. Other countries in the south-western Pacific region may have power plants or airports with similar risk, so it should be assessed against future tsunami disasters. Inundated thermal power plant in Pago Pago Debris on runway in Tafuna Airport (Provided by Mr. Chris Soti, DPA)

  16. Near-field survey of the 1946 Aleutian tsunami on Unimak and Sanak Islands

    USGS Publications Warehouse

    Okal, E.A.; Plafker, G.; Synolakis, C.E.; Borrero, J.C.

    2003-01-01

    The 1946 Aleutian earthquake stands out among tsunamigenic events because it generated both very high run-up near the earthquake source region and a destructive trans-Pacific tsunami. We obtained new data on the distribution of its tsunami in the near field along south-facing coasts between Unimak Pass on the west and Sanak Island on the east by measuring the height of driftwood and beach materials that were deposited by the tsunami above the extreme storm tide level. Our data indicate that (1) the highest measured run-up, which is at the Scotch Cap lighthouse, was 42 m above tide level or about 37 m above present storm tide elevation; (2) run-up along the rugged coast from Scotch Cap for 12 km northwest to Sennett Point is 12-18 m, and for 30 km east of Scotch Cap to Cape Lutke it is 24-42 m; (3) run-up along the broad lowlands bordering Unimak Bight is 10-20 m, and in-undation is locally more than 2 km; (5) run-up diminishes to 8 m or less at the southeast corner of Unimak Island; (6) no evidence was found for run-up above present storm tides (about 4-5 m above MLLW) on the Ikatan Peninsula or areas along the coast to the west; and (7) run-up above storm tide level in the Sanak Island group is restricted to southwest-facing coasts of Sanak, Long, and Clifford Islands, where it is continuous and locally up to 24 m high. Generation of the tsunami by one or more major earthquake-triggered submarine landslides near the shelf edge south of Unimak Island seems to be the only viable mechanism to account for the data on wave arrival time, run-up heights, and distribution, as well as for unconfirmed anecdotal reports of local postquake increases in water depth and diminished bottom-fisheries productivity. A preliminary hydrodynamic simulation of the local tsunami propagation and run-up using a dipolar model of a possible landslide off Davidson Bank provides an acceptable fit to the characteristics of the distribution of local run-up, with a value at 34 m at the Scotch Cap

  17. Eastern Australia's submarine landslides: implications for tsunami hazard between Jervis Bay and Fraser Island

    NASA Astrophysics Data System (ADS)

    Clarke, S. L.; Hubble, T.; Airey, D. W.; Ward, S. N.

    2015-12-01

    A hazard assessment of submarine landslide generated tsunami for the east Australian continental slope is presented between Jervis Bay and Fraser Island. Submarine landslides are present in water depths of ~400 to 3500 m along the entire length of continental margin, but are increasingly prevalent northward of Coffs Harbour without clustering at any particular water depth. Two hundred and fifty individual submarine landslide scars greater than one kilometre in width are identified. Of these, thirty-six are calculated to produce a tsunami flow depth equal to or greater than 5 m at the coastline for an assumed landslide downslope velocity of 20 ms-1. Some landslides are both thick (>100 m) and wide (>5 km) and these have the greatest potential to generate the largest coastal flow depths (>10 m). Water depth of the landslides centre of mass strongly influences the onshore height of the tsunami's surge with the larger events generated in shallower water depths between ~500 -1500 m. Maximum flow depth at the coastline is larger for thicker (50-250+ m) canyon landslides which occur on steeper slopes (>4°), compared to thinner (<50 m) plateau landslides which generally produce smaller tsunami. Maximum inundation distances and run-up heights of 1.6 km and 22 m respectively are calculated for landslide velocities of 20 ms-1. These values vary significantly depending on local coastal topography. There is no evidence for a submarine landslide large enough and young enough to have generated a Holocene megatsunami for the east coast of Australia.

  18. Variations in population exposure and evacuation potential to multiple tsunami evacuation phases on Alameda and Bay Farm Islands, California

    NASA Astrophysics Data System (ADS)

    Peters, J.

    2015-12-01

    Planning for a tsunami evacuation is challenging for California communities due to the variety of earthquake sources that could generate a tsunami. A maximum tsunami inundation zone is currently the basis for all tsunami evacuations in California, although an Evacuation Playbook consisting of specific event-based evacuation phases relating to flooding severity is in development. We chose to investigate the Evacuation Playbook approach for the island community of Alameda, CA since past reports estimated a significant difference in numbers of residents in the maximum inundation zone when compared to an event-based inundation zone. In order to recognize variations in the types of residents and businesses within each phase, a population exposure analysis was conducted for each of the four Alameda evacuation phases. A pedestrian evacuation analysis using an anisotropic, path distance model was also conducted to understand the time it would take for populations to reach high ground by foot. Initial results suggest that the two islands of the City of Alameda have different situations when it comes to the four tsunami evacuation phases. Pedestrian evacuation results suggest that Bay Farm Island would have more success evacuating by vehicle due to limited nearby high ground for pedestrians to reach safety. Therefore, agent-based traffic simulation software was used to model vehicle evacuation off Bay Farm Island. Initial results show that Alameda Island could face challenges evacuating numerous boat docks and a large beach for phases 1 and 2, whereas Bay Farm Island is unaffected at these phases but might be challenged with evacuating by vehicle for phases 3 and maximum due to congestion on limited egress routes. A better understanding of the population exposure within each tsunami Evacuation Playbook phase and the time it would take to evacuate out of each phase by foot or vehicle will help emergency managers implement the evacuation phases during an actual tsunami event.

  19. Assessing tsunami-induced groundwater salinization and its temporal change: a numerical modelling study on the Niijima Island, Japan

    NASA Astrophysics Data System (ADS)

    Liu, Jiaqi; Tokunaga, Tomochika

    2016-04-01

    Groundwater is vulnerable to many natural hazards, including tsunami. As reported after the 2004 Indian Ocean earthquake and the 2011 Great East Japan earthquake, the generated massive tsunami inundations resulted in unexpected groundwater salinization in coastal areas. Water supply was strongly disturbed due to the significantly elevated salinity in groundwater. Supplying fresh water is one of the prioritized concerns in the immediate aftermath of disaster, and during long-term post-disaster reconstruction as well. The aim of this study is to assess the impact of tsunami on coastal groundwater system and provide guidelines on managing water resources in post-tsunami period. We selected the study area as the Niijima Island, a tsunami-prone area in Japan, which is under the risk of being attacked by a devastated tsunami with its wave height up to 30 m. A three-dimension (3-D) numerical model of the groundwater system on the Niijima Island was developed by using the simulation code FEFLOW which can handle both density- dependent groundwater flow and saturated-unsaturated flow processes. The model was justified by the measured water table data obtained from the field work in July, 2015. By using this model, we investigated saltwater intrusion and aquifer recovery process under different tsunami scenarios. Modelling results showed that saltwater could fully saturate the vadose zone and come into contact with groundwater table in just 10 mins. The 0.6 km2 of inundation area introduced salt mass equivalent to approximately 9×104 t of NaCl into the vadose zone. After the retreat of tsunami waves, the remained saltwater in vadose zone continuously intruded into the groundwater and dramatically salinized the aquifer up to about 10,000 mg/L. In the worst tsunami scenario, it took more than 10 years for the polluted aquifer to be entirely recovered by natural rainfall. Given that the groundwater is the only freshwater source on the Niijima Island, we can provide suggestions

  20. The Mapping of Temporary Evacuation Site (TES) and Tsunami Evacuation Route in North Pagai Island, Mentawai Islands Regency - Indonesia

    NASA Astrophysics Data System (ADS)

    Putra, Aprizon; Mutmainah, Herdiana

    2016-11-01

    Mentawai Islands Regency, especially north Pagai island, suffered two earthquakes on April 15 2016. The local government in cooperation with the relevant parties had tried to minimize casualties before the disaster or during the disaster by making an evacuation route to the TES. The purpose of this study was to the mapping of TES and tsunami evacuation route using the approach of Geographic Information Systems (GIS) for disaster mitigation of tsunami-potential earthquake in north Pagai island.The research was conducted at 3 locations in the coast of Sikakap village, 4 locations in the coast of Taikako village, 3 locations in the coast of Silabu village, 7 locations in the coast of Saumanganya village, and 3 locations in the coast of Matobe village. The effort taken was to evacuate people to the TES with an average distance of 372.62 m from the beach. The results showed that the feasibility of TES that could accommodate residents, among others, were in the hills behind Sikakap Port, Taikako Silaoinan hills, the hills near the Mapinang Silabu village chief's office and Mapinang hills, Gulukguluk Saumanganya and Panatarat Matobe hills.

  1. Zero Magnitude Effect for the Productivity of Triggered Tsunami Sources

    NASA Astrophysics Data System (ADS)

    Geist, E. L.

    2013-12-01

    The Epidemic Type Aftershock Sequence (ETAS) model is applied to tsunami events to explain previously observed temporal clustering of tsunami sources. Tsunami events are defined by National Geophysical Data Center (NGDC) tsunami database. For the ETAS analysis, the earthquake magnitude associated with each tsunami event in the NGDC database is replaced by the primary magnitude listed in the Centennial catalog up until 1976 and in the Global CMT catalog from 1976 through 2010. Tsunamis with a submarine landslide or volcanic component are included if they are accompanied by an earthquake, which is most often the case. Tsunami size is used as a mark for determining a tsunami-generating event, according to a minimum completeness level. The tsunami catalog is estimated to be complete for tsunami sizes greater than 1 m since 1900 and greater than 0.1 m since 1960. Of the five parameters in the temporal ETAS model (Ogata, 1988), the parameter that scales the magnitude dependence in the productivity of triggered events is the one that is most different from ETAS parameters derived from similar earthquake catalogs. Maximum likelihood estimates of this magnitude effect parameter is essentially zero, within 95% confidence, for both the 0.1 m and 1.0 m tsunami completeness levels. To explain this result, parameter estimates are determined for the Global CMT catalog under three tsunamigenic conditions: (1) M≥7 and focal depth ≤50 km, (2) submarine location, and (3) dominant component of dip slip. Successive subcatalogs are formed from the Global CMT catalog according to each of these conditions. The high magnitude threshold for tsunamigenesis alone (subcatalog 1) does not explain the zero magnitude effect. The zero magnitude effect also does not appear to be caused the smaller number of tsunamigenic events analyzed in comparison to earthquake catalogs with a similar magnitude threshold. ETAS parameter estimates from the subcatalog (3) with all three tsunamigenic conditions

  2. Documenting the Distribution and Sedimentology of the Penultimate Tsunami Along a Cross Island Transect on Koh Phra Thong Island, Thailand

    NASA Astrophysics Data System (ADS)

    Kirby, M. E.; Rhodes, B. P.; Leeper, R. J.; Choowong, M.

    2013-12-01

    Thailand's Koh Phra Thong Island is characterized by ridge-swale topography. Unlike the ridges, swales often hold water during the wet season, which allows for the deposition and preservation of sediment. As a result, swales are potential archives for past tsunami deposits. Seven different swale sites along a 1.9 km transect on the northern half of the island were trenched to investigate the occurrence and distribution of paleo-tsunami deposits. Duplicate overlapping slab cores were taken from the trench walls. Cores from sites F111, F511, F611, and F811 were analyzed at 1 cm contiguous intervals for magnetic susceptibility, percent organic matter, percent total carbonate, and grain size. Each site contained at least one distinct penultimate tsunami (PT) unit. Although the quality of preservation of the PT sediment unit diminishes with distance from the modern shoreline, presumably caused by differential bioturbation, grain size distributions and organic matter content clearly demarcate each PT unit. Notably, the distribution of sand sizes throughout the PT is not the same landward. More distal sites (F611 and F811) are dominated by very fine to fine sands; whereas, the mid island site (F511) is sand and coarse sand dominated. Microscopic charcoal was picked under a binocular scope to bracket the PT unit. A maximum age of 620 cy BP was obtained for the most distal site (F811). Ages spanning 740 - 900 cy BP provide a maximum age for the PT unit at F511. Ages for the PT unit from near the present day shoreline are similar (550 - 770 cy BP: Jankaew et al., 2008) using radiocarbon methods. OSL dates from the PT unit sands show an age 380×50 years before AD 1950 (Prendergast et al., 2012). From these various ages, the PT unit was deposited no earlier than 900 cy BP but likely no later than 380×50 years before AD 1950.

  3. Coastal Impacts of the March 11th Tsunami in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Lynett, P. J.; Weiss, R.; Renteria, W.

    2011-12-01

    On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Local Time, Galapagos), the magnitude 9.0 Mw Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan. The purpose of this presentation is to provide the results of a tsunami field survey in the Galapagos Islands performed by an International Tsunami Survey Team (ITST) with great assistance from INOCAR, the oceanographic service of the Ecuadorian Navy, and the Galapagos National Park. The Galapagos Islands are a volcanic chain composed of many islands of various sizes. The four largest islands are the focus of this survey, and are, from west to east, Isabela, Santiagio, Santa Cruz, and San Cristobal. Aside from approximately 10 sandy beaches that are open to tourists, all other shoreline locations are strictly off limits to anyone without a research permit. All access to the shoreline is coordinated through the Galapagos National Park, and any landing requires a chaperone, a Park Ranger. While a few of the visited areas in this survey were tourist sites, the vast majority were not. Due to time constraints and a generally inaccessibility of the coastline, the survey locations were strongly guided by numerical computations performed previous to the surveys. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum flow elevations were generally in the range of 3-4 meters, while Isabela experienced the largest flow elevation of 6 m in a small pocket beach. The largest harbor in the Islands, Puerto Ayora, experienced moderate damage, with significant flooding and some structural damage. Currents in the Baltra Channel, a small waterway between Santa Cruz and Baltra, were strong enough to transport navigation buoys distances greater than 800 m. Extreme dune erosion, and the associated destruction of sea turtle nesting habit, was widespread and noted on all of the islands visited.

  4. Tsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska

    USGS Publications Warehouse

    Nelson, Alan R.; Briggs, Richard; Dura, Tina; Engelhart, Simon E.; Gelfenbaum, Guy; Bradley, Lee-Ann; Forman, S.L.; Vane, Christopher H.; Kelley, K.A.

    2015-01-01

    cannot estimate source earthquake locations or magnitudes for most tsunami-deposited beds. We infer that no more than 3 of the 23 possible tsunamis beds at both sites were deposited following upper plate faulting or submarine landslides independent of megathrust earthquakes. If so, the Semidi segment of the Alaska-Aleutian megathrust near Chirikof Island probably sent high tsunamis southward every 180–270 yr for at least the past 3500 yr.                   

  5. Tohoku-Oki Earthquake Tsunami Runup and Inundation Data for Sites Around the Island of Hawaiʻi

    USGS Publications Warehouse

    Trusdell, Frank A.; Chadderton, Amy; Hinchliffe, Graham; Hara, Andrew; Patenge, Brent; Weber, Tom

    2012-01-01

    At 0546 U.t.c. March 11, 2011, a Mw 9.0 ("great") earthquake occurred near the northeast coast of Honshu Island, Japan, generating a large tsunami that devastated the east coast of Japan and impacted many far-flung coastal sites around the Pacific Basin. After the earthquake, the Pacific Tsunami Warning Center issued a tsunami alert for the State of Hawaii, followed by a tsunami-warning notice from the local State Civil Defense on March 10, 2011 (Japan is 19 hours ahead of Hawaii). After the waves passed the islands, U.S. Geological Survey (USGS) scientists from the Hawaiian Volcano Observatory (HVO) measured inundation (maximum inland distance of flooding), runup (elevation at maximum extent of inundation) and took photographs in coastal areas around the Island of Hawaiʻi. Although the damage in West Hawaiʻi is well documented, HVO's mapping revealed that East Hawaiʻi coastlines were also impacted by the tsunami. The intent of this report is to provide runup and inundation data for sites around the Island of Hawaiʻi.

  6. Effects of fringing reefs on tsunami inundation: American Samoa

    NASA Astrophysics Data System (ADS)

    Gelfenbaum, Guy; Apotsos, Alex; Stevens, Andrew W.; Jaffe, Bruce

    2011-07-01

    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

  7. 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

  8. Random focusing of tsunami waves

    NASA Astrophysics Data System (ADS)

    Degueldre, Henri; Metzger, Jakob J.; Geisel, Theo; Fleischmann, Ragnar

    2016-03-01

    Tsunamis exhibit surprisingly strong height fluctuations. An in-depth understanding of the mechanisms that lead to these variations in wave height is a prerequisite for reliable tsunami forecasting. It is known, for example, that the presence of large underwater islands or the shape of the tsunami source can affect the wave heights. Here we show that the consecutive effect of even tiny fluctuations in the profile of the ocean floor (the bathymetry) can cause unexpectedly strong fluctuations in the wave height of tsunamis, with maxima several times higher than the average wave height. A novel approach combining stochastic caustic theory and shallow water wave dynamics allows us to determine the typical propagation distance at which the strongly focused waves appear. We demonstrate that owing to this mechanism the small errors present in bathymetry measurements can lead to drastic variations in predicted tsunami heights. Our results show that a precise knowledge of the ocean's bathymetry is absolutely indispensable for reliable tsunami forecasts.

  9. Numerical simulations to account for boulder movements on Lanyu Island, Taiwan: tsunami or storm?

    NASA Astrophysics Data System (ADS)

    Nakamura, Mamoru; Arashiro, Yasuhisa; Shiga, Shota

    2014-12-01

    Boulders that originated from the Holocene coral terrace and coral reef are distributed on the coral terrace or talus on the shore of Lanyu Island, Taiwan. We employed numerical simulation of storm waves and estimated whether the boulders could be moved by storm waves with a return period of 50 years, by larger storm waves with return periods of hundreds of years, or by tsunamis. The coral boulders are distributed between 36 and 128 m from the shoreline at elevations of 2.7 to 9.3 m. The sizes of the boulders are in the range 0.3 to 6.4 m. The boulder volume and a-axis length versus distance from the shore show weak and moderate correlation ( r = 0.21 and 0.48), respectively. We reproduced the runup of waves using the equation of continuity for a two-dimensional non-compressive fluid and the Navier-Stokes formula. In order to handle the free surface of the fluid, the volume of fluid method was applied. For the flow velocity to move the boulder, we employed the theoretical formula for the transport of boulders. We used the wave height for a return period of 50 years and set the height of the input wave to 13.1 m. The results show that all the large boulders on Lanyu Island could be moved by storm waves with a return period of 50 years. Moreover, the computations show that most of the boulders could not have been transported by tsunamis generated by the Mw8.7 earthquakes. The ages of two boulders indicate that they were transported after 340 and 6,330 years ago. If these boulders were moved by tsunamis several hundred years ago, they would have been relocated subsequently by storm waves.

  10. Field survey, modeling and free oscillations of the 2010 Chilean tsunami in the Marquesas Islands, French Polynesia

    NASA Astrophysics Data System (ADS)

    Allgeyer, S.; Reymond, D.; Hyvernaud, O.; Jamelot, A.; Okal, E.; Hebert, H.; Madariaga, R. I.

    2010-12-01

    On the 27 February 2010, a magnitude of 8.8 occurred in front of the Maule and Bio Bio regions of south central Chile. The event broke a band on the plate interface of 450 km length by 140 km in width. The French Polynesia Tsunami Warning System (CPPT), located in Tahiti, notified French Polynesia authorities through tsunami information bulletin about a red tsunami warning level, the highest warning level. All coastal areas in Polynesia were evacuated starting 03:00 Tahiti time (GMT-10), three to five hours ahead of the arrival of the first waves, thus preventing any casualties. Observed tide gauges show a maximum amplitude of 0.3 meter in Tahiti and more than 3 meters in Marquesas. This difference in amplitude is observed for all tsunamis reaching French Polynesia. It is indeed well known that Marquesas are more sensitive to tsunamis. This is due to the absence of coral reef around these islands, and the mild slope bathymetry when a tsunami approaches the shores. According to the observations in the Marquesas, strong amplification and long duration of the water disturbance observations were reported. Spectral analysis of tide gauge time series shows several free oscillations periods. We will present the results of field surveys achieved during the second week in March 2010. Simulations of the inundation at selected locations on Polynesian islands will be compared with observed run-up values and available tsunami heights measured on tide gauges. In addition, a more detailed analysis of free oscillations in the Marquesas Archipelago was done using several tide gauge time series of different events originated in South America, the Kuriles Islands and the Tonga-Kermadec region. We also use synthetic sources to study the possible azimuthal dependance of the excitation of these eigenperiods. An alternative way to determine free oscillations is to use analytic calculation of different eigenfunctions of the wave equation to find the oscillations periods.

  11. Comparison of Tsunami height Distributions of the 1960 and the 2010 Chilean Earthquakes on the Coasts of the Japanese Islands

    NASA Astrophysics Data System (ADS)

    Tsuji, Y.; Takahashi, T.; Imai, K.

    2010-12-01

    The tsunami of the Chilean Earthquake (Mw8.8) of February 27, 2010 was detected also on the coasts of the Japanese Islands about 23 hours after the occurrence of the main shock. It caused no human damage. There was slight house damage manly in Miyagi prefecture, south part of Sanriku coast; six and fifty one houses were flooded above and below the floor, respectively. It caused remarkable fishery loss of 75 Million US$ mainly due to breaking of cultivation rafts. The tsunami of the 1960 Chilean Earthquake(Mw9.5) also hit the Japanese coasts more severely. It caused more immense damage than the 2010 tsunami; 142 people were killed, 1,581 houses were entirely destroyed, and 1,256 houses were swept away. Most of damage occurred in the districts of Sanriku coast, where inundation heights exceeded six meters at several points. We made field survey along the Japanese coast, visited offices of fishermen’s cooperatives at over 300 fishery ports, gathered eyewitnesses counts, and obtained information of the inundation limit, arrival time, and building and fishery damage. On the basis of the information of inundation, we measured tsunami heights. We obtained data of tsunami height at more than two hundred points (Tsuji et al., 2010). The distributions of the two tsunamis of the 1960 and the 2010 Chilean earthquakes on the coasts along the Japanese Islands are shown as Fig. 1. The maximum height of 2.2 meters was recorded at Kesennuma City, Miyagi Prefecture. The heights of the 2010 tsunami were generally one third of those of the 1960 tsunami. An eminent peak appears at Sanriku coast commonly for both tsunamis. In addition smaller peaks also appear commonly at the coasts of the east part of Hokkaido, near the top of Boso peninsula, near the top of Izu Peninsula, the east coast of Kii Peninsula, Tokushima prefecture, eastern part of Shikoku, and near the Cape Ashizuri in western part of Shikoku. Fig. 1 Trace height distributions of the tsunamis of the 1960(red) and the 2010

  12. Deposits, flow characteristics, and landscape change resulting from the September 2009 South Pacific tsunami in the Samoan islands

    PubMed Central

    Richmond, Bruce M.; Buckley, Mark; Etienne, Samuel; Chagué-Goff, Catherine; Clark, Kate; Goff, James; Dominey-Howes, Dale; Strotz, Luke

    2011-01-01

    The September 29th 2009 tsunami caused widespread coastal modification within the islands of Samoa and northern Tonga in the South Pacific. Preliminary measurements indicate maximum runup values of around 17 m (Okal et al., 2010) and shore-normal inundation distances of up to ~ 620 m (Jaffe et al., 2010). Geological field reconnaissance studies were conducted as part of an UNESCO-IOC International Tsunami Survey Team survey within three weeks of the event in order to document the erosion, transport, and deposition of sediment by the tsunami. Data collected included: a) general morphology and geological characteristics of the coast, b) evidence of tsunami flow (inundation, flow depth and direction, wave height and runup), c) surficial and subsurface sediment samples including deposit thickness and extent, d) topographic mapping, and e) boulder size and location measurements. Four main types of sedimentary deposits were identified: a) gravel fields consisting mostly of isolated cobbles and boulders, b) sand sheets from a few to ~ 25 cm thick, c) piles of organic (mostly vegetation) and man-made material forming debris ramparts, and d) surface mud deposits that settled from suspension from standing water in the tsunami aftermath. Tsunami deposits within the reef system were not widespread, however, surficial changes to the reefs were observed. PMID:27065478

  13. Deposits, flow characteristics, and landscape change resulting from the September 2009 South Pacific tsunami in the Samoan islands.

    PubMed

    Richmond, Bruce M; Buckley, Mark; Etienne, Samuel; Chagué-Goff, Catherine; Clark, Kate; Goff, James; Dominey-Howes, Dale; Strotz, Luke

    2011-07-01

    The September 29th 2009 tsunami caused widespread coastal modification within the islands of Samoa and northern Tonga in the South Pacific. Preliminary measurements indicate maximum runup values of around 17 m (Okal et al., 2010) and shore-normal inundation distances of up to ~ 620 m (Jaffe et al., 2010). Geological field reconnaissance studies were conducted as part of an UNESCO-IOC International Tsunami Survey Team survey within three weeks of the event in order to document the erosion, transport, and deposition of sediment by the tsunami. Data collected included: a) general morphology and geological characteristics of the coast, b) evidence of tsunami flow (inundation, flow depth and direction, wave height and runup), c) surficial and subsurface sediment samples including deposit thickness and extent, d) topographic mapping, and e) boulder size and location measurements. Four main types of sedimentary deposits were identified: a) gravel fields consisting mostly of isolated cobbles and boulders, b) sand sheets from a few to ~ 25 cm thick, c) piles of organic (mostly vegetation) and man-made material forming debris ramparts, and d) surface mud deposits that settled from suspension from standing water in the tsunami aftermath. Tsunami deposits within the reef system were not widespread, however, surficial changes to the reefs were observed.

  14. Geochemical Characteristics of Typhoon - and Tsunami - Induced Deposits from Western Kyushu Islands

    NASA Astrophysics Data System (ADS)

    Kanamaru, K.; Woodruff, J. D.; Kundu, S.; Cook, T.

    2014-12-01

    Western Kyushu Island is a region of Japan frequently impacted by typhoon landfalls. This region is relatively tectonically stable with few active faults and therefore known for far fewer great earthquakes when compared to the Nankai Trough region. Only a few studies have examined the history of tsunamis impacting the region. Hence, studies from western Kyushu provide a unique opportunity to study tsunami deposits in a broader geographic context in order to delineate regional typhoon impacts. This study presents results from both modern analogue from Typhoon Neoguri in 2014 and legendary Kamikaze Typhoons from 13th century. The initial coring was conducted in 2010. Total of 9 sediment cores were collected from two natural freshwater lakes along the western coast of Kyushu: Lake Daija (32.248°N, 129.985°E) and Lake Kawahara (32.624°N, 129.831°E). In order to further understand the characteristics of typhoon deposits, we collected 4 additional sediment cores from Kawahara in July of 2014, approximately one week after landfall of Typhoon Neoguri. We use a multi-proxy approach to identify event deposits. These approaches include loss on ignition, X-Ray fluorescence, X-radiograph, grain size, magnetic susceptibility, and SEM/EDS analyses. Initial results yielded commonalities between the two lakes. Linear interpolation of the most prominent event deposits within multiple cores, presenting highs in Sr and Ca intensities, constrain the dates of deposits of interest to the late 13th century—consistent with the Mongol invasions. Here we present preliminary geochemical results from Lake Kawahara, which further constrain the typhoon deposits, and use this as a reference event for comparison to tsunami deposits found in other regions.

  15. Studying and Dating Indian Ocean Tsunamis by Using Benthic Foraminifera in the Sediment Stratigraphy of South Andaman Islands, India

    NASA Astrophysics Data System (ADS)

    Johnson, F. C.

    2015-12-01

    We analyzed the foraminifera and dated them to identify the sea level fluctuations in the coastal sediment stratigraphy of Andaman Islands. Our recent paleotsunami investigations are specially focused on unusual large magnitude earthquake and tsunamis in the south coast of Andaman. Our detailed study on the foraminifers preserved in the near sub surface stratigraphy and AMS ages show a strong signature of the tsunami event very much similar to the modern tsunami of December 2004. We found that foraminifer is an ideal geological key to bracket paleotsunami events. The AMS ages of these foraminifers supports the ages given by corals of Sumatra with a small error bar. The recent research approach to identify the ruptures and tsunami based on the corals of south Sumatra suggests a large time span of 1000 years for such mega events. Our foraminiferal archives obtained from 10g soil samples from the 2.5m deep Holocene stratigraphy suggests four seismic predecessors similar to the 2004 event with ~Mw9 with huge rupture. Huge foraminiferal population in the sedimentary stratigraphy is an indicative of sea level changes and the signatures of abrasion in the foraminifer's test (180µm) indicate strong wave surges and bead load transport during tsunami events. Spontaneous death of organisms due to tsunami waves gives an exact time frame with a narrow age limit than the charcoal. Sediment stratigraphy of south Andaman had such changes in each millennium. Sediment stratigraphy sections shows the huge population and assemblages and the AMS dates of this foraminifera in south Andaman shows four mega events. This kind of fossil assemblages are commonly associated with the sea regression and transgressions in the geological time scale. Tamil 'Sangam literatures' one of the oldest literature available in Indian main land and the corals ages from Sumatra are also emphasizes the predecessors of such unusual large magnitude earthquakes and tsunamis in the Indian Ocean. All these

  16. Near-field tsunami inferred from numerical modeling of medieval overwash at Anegada, British Virgin Islands

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Ten Brink, U. S.; Atwater, B. F.; Tuttle, M. P.; Robert, H.; Feuillet, N.; Jennifer, W.; Fuentes, Z.

    2012-12-01

    In a comparison among numerical models of storms and tsunamis, only tsunami waves of nearby origin manage to wash over an area where coral heads of medieval age are scattered hundreds of meters inland from the north shore of Anegada, British Virgin Islands. This low-lying island faces the Puerto Rico Trench 120 km to the north. The island's north shore, fringed by a coral reef 100-1200 m offshore, displays geological evidence for two levels of overwash. The medieval overwash, dated to AD 1200-1450, was the higher one. It is evidenced by scores of coral boulders scattered hundreds of meters inland. Some of them crossed the area of the modern storm berm at Soldier Wash, continued across a broad limestone rise 3-4 m above sea level, and came to rest on lower ground farther inland. Coral heads in four other areas, also medieval or older, came to rest hundreds of meters inland from beach ridges now 2-4 m above sea level. The later, lower-elevation overwash, dated to AD 1650-1800, laid down a sheet of sand and shell that extends as much as 1.5 km inland. The hypothetical causes for each event, tested by numerical modeling, include (1) category IV and V hurricanes that differ in surge and wave heights; (2) the 1755 Lisbon earthquake or hypothetical medieval predecessor, at M 8.7 and M 9.0; (3) M 8.4 thrust earthquake along the Puerto Rico Trench between Hispaniola and Anegada; (4) M 8.7 thrust along the Puerto Rico Trench between Tortola and Antigua; (5) M 8.0 earthquake from normal faulting on the outer rise north of Anegada. The model output includes extent of onshore flooding, depth and velocity of overland flow, and energy lost by tsunami and hurricane waves as they cross the reef and continue across a shallow subtidal flat to Anegada's north shore. For the medieval overwash, the modeling is most conclusive in testing various explanations for the coral boulders inland of Soldier Wash. The simulated hurricane waves do not wash inland of the storm berm; the height of

  17. Improving tsunami resiliency: California's Tsunami Policy Working Group

    USGS Publications Warehouse

    Real, Charles R.; Johnson, Laurie; Jones, Lucile M.; Ross, Stephanie; 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.

  18. The 29th September Samoa Islands tsunami: preliminary simulations based on the first focal mechanisms hypotheses and implications of uncertainties in tsunami early warning strategies

    NASA Astrophysics Data System (ADS)

    Tonini, R.; Pagnoni, G.; Armigliato, A.; Tinti, S.

    2009-12-01

    At 6:48 AM local time (17:48 UTC time) a strong earthquake of magnitude Mw=8.0 occurred less than 200 km south of the Samoa Islands (Western Samoa and American Samoa), triggering a tsunami that was detected by several tide gauges located all around the source area. The areas most affected were the south coasts of Western and American Samoa, where almost 200 persons were killed and run-up heights were measured in excess of 5 meters on several locations along the coast and and the tide gauges reached a maximum peak-to-peak height of about 3 meters near Pago-Pago (American Samoa) and 1.5 meters in front of Apia (Western Samoa) The existence of many tide gauge records is important to support the investigation of the source mechanism. The epicenter of this earthquake is located very close to the point where the Tonga trench turns its direction from northward to westward. Here the Pacific plate moves westward beneath the Australia plate, determining a subduction zone along the north-oriented segment of the trench and a transform zone along the west-oriented segment. The epicenter location in this complex tectonic context makes identifying the fault mechanism responsible for the tsunami generation a non-trivial task. The goal of this preliminary work is testing different fault models based on the focal mechanism solution proposed by USGS, CMT and EMSC for this earthquake, through the comparison between the tide gauge records and the synthetic signals provided by the numerical simulations, and possibly suggesting new source solutions trying to reproduce as better as possible the tsunami recordings. The numerical simulations are computed by means of the UBO-TSUFD code, developed and maintained by the Tsunami Research Team of the University of Bologna, Italy. The code solves the linear and non-linear shallow water equations and can compute inundation inland. Furthermore the computational domain can be split in grids of different space resolution in order to have more

  19. Three-Dimensional Simulation of Tsunami Run Up Around Conical Island Using Smoothed Particle Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Buruchenko, Sergey K.

    2016-10-01

    The large-scale laboratory experiments were performed in a 30 m-wide, 25 m-long, and 60 cm-deep wave basin. Waves were realistically created in the tank by a horizontal wave generator with 60 different paddles each 46 cm-wide and moving independently. These experiments provided run-up observations for validating numerical models and supplemented comparisons with analytical results. Smoothed particle hydrodynamics (SPH) is a popular meshfree, Lagrangian method with attractive features in modelling fluid dynamics. The SPH method is capable of dealing with problems with free surface, deformable boundary, moving interface, wave propagation and solid simulation. A weakly incompressible fluid flow SPH model was employed in this paper to investigate the run-up heights of nearshore tsunamis in the vicinity of a circular island. The predicted numerical results have been verified by comparing to available laboratory measurements. A good agreement has been observed.

  20. Impact of the earthquake and tsunami of December 26, 2004, on the groundwater regime at Neill Island (south Andaman).

    PubMed

    Singh, V S

    2008-10-01

    The aquifer and groundwater regime has been affected by the earthquake and tsunami of December 26, 2004, particularly on the islands and coastal regions of India. The groundwater regime on many islands of Andaman and Nicobar islands, which is the only source of fresh water on the islands, has been found to be deteriorated. Detailed hydrogeological studies have been carried out at one of the tiny islands of Andaman, namely Neill Island, and results have been compared with prior observations. It has been found that the shell limestone aquifer at a few places has developed cracks due to the earthquake and these openings have allowed quick movement of seawater into the aquifer resulting into deterioration of groundwater quality. In the places where the aquifer is at sea level, the tsunami waves have caused seawater ingress. Most parts of the island which have hard mudstone as a base and where the aquifer lies much above sea level, did not show any change in groundwater regime.

  1. Stratigraphic evidence for earthquakes and tsunamis on the west coast of South Andaman Island, India during the past 1000 years

    NASA Astrophysics Data System (ADS)

    Malik, Javed N.; Banerjee, Chiranjib; Khan, Afzal; Johnson, Frango C.; Shishikura, Masanobu.; Satake, Kenji.; Singhvi, Ashok K.

    2015-10-01

    Stratigraphic records from west coast of South Andaman Island revealed evidence of three historical earthquakes and associated transoceanic tsunamis during past 1000 yrs, in addition to the Mw 9.3 tsunamigenic earthquake of 26 December, 2004. Our finding suggests that along with Sumatran arc segment the Andaman-Arakan segment is also capable of generating mega-subduction zone earthquakes and transoceanic tsunamis. To study the near sub-surface stratigraphic succession we excavated shallow trenches and obtained geoslices from two sites around Collinpur (sites 1 and 2). The exposed succession comprised 11 lithounits (Unit a - youngest and k - oldest) of alternating sequence of coarser units overlain by peaty soils and some of these are indicative of deposition during paleo-tsunami events. Event I that predated AD 800, and is marked by a 35-40 cm thick deposit of fine gravel to coarse sands along with broken shell fragments (Unit k). Event II dated around AD 660-800, is represented by 20-25 cm thick coarse sand and broken shell fragments (Unit i). Based on stratigraphic evidences of land-level changes, this event is attributed to a near source rupture along Andaman-Arakan segment, accompanied by a transoceanic tsunami. Event III, occurred around AD 1120-1300, is marked by a 50 cm thick sand deposit (Unit g). The 2004 tsunami resulted in deposition of 15 cm thick medium to coarse sand at the same location. We infer that the 2004 tsunami and Event III resulted in different styles of sedimentation at the same site. Four events at Collinpur along with the record of a subsidence event of AD 1679 from the east coast of Andaman, close-to, Port Blair (Malik et al., 2011), suggest that mega-subduction zone earthquakes and associated tsunamis recur at an interval of 300-500 years at variable locations along the Sumatra-Andaman subduction zone.

  2. Coral recruitment and recovery after the 2004 Tsunami around the Phi Phi Islands (Krabi Province) and Phuket, Andaman Sea, Thailand

    NASA Astrophysics Data System (ADS)

    Sawall, Y.; Phongsuwan, N.; Richter, C.

    2010-12-01

    The 2004 tsunami left a discontinuous pattern of destruction in the reefs along Andaman Sea coast of Thailand. Here, a comparative assessment of coral recruitment was carried out to assess differences in recovery between damaged and undamaged sites in near-shore fringing reefs 1 and 3 years after the tsunami. Settlement plates showed high frequencies of coral spat after 4 months (<17 spat tile-1) in both, damaged and undamaged locations. Field surveys carried out 3 years after the tsunami on natural substrate confirmed that tsunami damage did not suppress recruitment in damaged sites relative to no impacted controls. New and stable settlement space along with unabated larval supply supported post-tsunami recruit densities up to 7.2 m-2 year-1. Mean recruit densities were found at the level of post-storm situations with rapid recovery success, suggesting that the duration of disturbance, degree of sorting and, hence, stability of coral rubble is a key determinant of recruitment success. Low regeneration success of some species e.g. branching acroporids and rebounding tourism industry at sites like Patong and partly around the Phi Phi Islands (dense carpets of filamentous algae) led to the assumption of selectivity and eventually to an alternation of the coral community even though live coral cover might be recovered soon.

  3. Regional Impact of the 29 September 2009 North Tonga Tsunami on the Futuna and Alofi Islands (Wallis & Futuna)

    NASA Astrophysics Data System (ADS)

    Lamarche, G.; Pelletier, B.; Goff, J. R.

    2009-12-01

    The north Tonga earthquake occurred at 5:48am on 30 September local time in Futuna, ~650 km west of the epicentre. The PTWC issued a warning at 6:04am for tsunami arrival in Wallis (Wallis & Futuna) at 6.35am. No warning was issued by the territorial authorities for Wallis nor for Futuna, located 230 km to the south-west. There was no reported tsunami on Wallis. However a tsunami hit the archipelago of Futuna (islands of Futuna and Alofi) between 7.00 and 7.20am on 30 September. The tide was approximately 3/4 out. We took advantage of an 8 days survey funded by the French Ministry of Foreign Affairs, previously planned for investigating palaeotsunamis on Futuna and Alofi. We measured run-up and inundation from the mid- to low-tide mark, as well as flow depths, and sediments associated with the 30 September tsunami at 41 sites around the islands. Run-ups were estimated based on visual evidence of recent coastal impact - burnt grasses and plants, sand and other displaced debris (e.g., on the road). We interviewed the population on multiple occasions. The maximum run-up of 4.5 m was observed on the eastern beach of Alofitai in Alofi, associated with an inundation of 85 m and a flow depth of 3m at the coast. On Futuna, we measured maximum run-ups of 4.4 m on the eastern tip and 4.3 m on the NW tip of the island, with maximum inundations of 95 and 72m, respectively. A flow depth of 2 m was inferred on the NE tip. Overall, the tsunami impact was more severe on the northern coast of Futuna, with run-ups ranging from 2.1 to 4.3 m. Very small run-ups and inundations were observed along the southern coast, with a 1.0 m run-up and 10 m inundation measured in Léava, the capital of Futuna. Most witnesses report two main waves equivalent in amplitude, the second one being sometimes described as the largest. All witnesses indicate that the sea withdrew first. A video suggests only a few minutes between the successive waves (likely not the first) in Léava. The video shows the

  4. Specification of Tectonic Tsunami Sources Along the Eastern Aleutian Island Arc and Alaska Peninsula for Inundation Mapping and Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Suleimani, E.; Nicolsky, D.; Freymueller, J. T.; Koehler, R.

    2013-12-01

    The Alaska Earthquake Information Center conducts tsunami inundation mapping for coastal communities in Alaska along several segments of the Aleutian Megathrust, each having a unique seismic history and tsunami generation potential. Accurate identification and characterization of potential tsunami sources is a critical component of our project. As demonstrated by the 2011 Tohoku-oki tsunami, correct estimation of the maximum size event for a given segment of the subduction zone is particularly important. In that event, unexpectedly large slip occurred approximately updip of the epicenter of the main shock, based on seafloor GPS and seafloor pressure gage observations, generating a much larger tsunami than anticipated. This emphasizes the importance of the detailed knowledge of the region-specific subduction processes, and using the most up-to-date geophysical data and research models that define the magnitude range of possible future tsunami events. Our study area extends from the eastern half of the 1957 rupture zone to Kodiak Island, covering the 1946 and 1938 rupture areas, the Shumagin gap, and the western part of the 1964 rupture area. We propose a strategy for generating worst-case credible tsunami scenarios for locations that have a short or nonexistent paleoseismic/paleotsunami record, and in some cases lack modern seismic and GPS data. The potential tsunami scenarios are built based on a discretized plate interface model fit to the Slab 1.0 model geometry. We employ estimates of slip deficit along the Aleutian Megathrust from GPS campaign surveys, the Slab 1.0 interface surface, empirical magnitude-slip relationships, and a numerical code that distributes slip among the subfault elements, calculates coseismic deformations and solves the shallow water equations of tsunami propagation and runup. We define hypothetical asperities along the megathrust and in down-dip direction, and perform a set of sensitivity model runs to identify coseismic deformation

  5. Applying and validating the PTVA-3 Model at the Aeolian Islands, Italy: assessment of the vulnerability of buildings to tsunamis

    NASA Astrophysics Data System (ADS)

    Dall'Osso, F.; Maramai, A.; Graziani, L.; Brizuela, B.; Cavalletti, A.; Gonella, M.; Tinti, S.

    2010-07-01

    The volcanic archipelago of the Aeolian Islands (Sicily, Italy) is included on the UNESCO World Heritage list and is visited by more than 200 000 tourists per year. Due to its geological characteristics, the risk related to volcanic and seismic activity is particularly high. Since 1916 the archipelago has been hit by eight local tsunamis. The most recent and intense of these events happened on 30 December 2002. It was triggered by two successive landslides along the north-western side of the Stromboli volcano (Sciara del Fuoco), which poured approximately 2-3×107 m3 of rocks and debris into the Tyrrhenian Sea. The waves impacted across the whole archipelago, but most of the damage to buildings and infrastructures occurred on the islands of Stromboli (maximum run-up 11 m) and Panarea. The aim of this study is to assess the vulnerability of buildings to damage from tsunamis located within the same area inundated by the 2002 event. The assessment is carried out by using the PTVA-3 Model (Papathoma Tsunami Vulnerability Assessment, version 3). The PTVA-3 Model calculates a Relative Vulnerability Index (RVI) for every building, based on a set of selected physical and structural attributes. Run-up values within the area inundated by the 2002 tsunami were measured and mapped by the Istituto Italiano di Geofisica e Vulcanologia (INGV) and the University of Bologna during field surveys in January 2003. Results of the assessment show that if the same tsunami were to occur today, 54 buildings would be affected in Stromboli, and 5 in Panarea. The overall vulnerability level obtained in this analysis for Stromboli and Panarea are "average"/"low" and "very low", respectively. Nonetheless, 14 buildings in Stromboli are classified as having a "high" or "average" vulnerability. For some buildings, we were able to validate the RVI scores calculated by the PTVA-3 Model through a qualitative comparison with photographs taken by INGV and the University of Bologna during the post-tsunami

  6. Public Awareness of a Long-Established Siren-Based Warning System for Tsunami in the Hawaiian Islands

    NASA Astrophysics Data System (ADS)

    Gregg, C.; Houghton, B.; Paton, D.; Johnston, D.

    2003-12-01

    Tsunami represent one of the greatest threats in the Hawaiian Islands because much of the built environment is located in the coastal areas and has been constructed after the last statewide damaging tsunami (1960). Moreover, the threat posed by short warning times of locally generated tsunami suggests an urgent need for a well briefed and prepared society. The Federal Emergency Alert System (EAS) is employed to communicate emergency information to the Hawaiian population (1.2 million residents; 6.4 million annual visitors). A network of sirens located throughout the islands supplements the EAS. These sirens have been used since the mid 20th Century to provide emergency information to islanders. The siren is currently defined as an "Attention Alert Signal" i.e. is intended to prompt people to listen to the radio or television for specific information. The sirens are tested monthly. Since the inception of the sirens there have been a range of tones and number of soundings used to indicate various threats and prompt specific public responses. However, the impact of these changes on interpretation of the sirens has received little attention (Lachman et al. 1961). The long time during which the warning system has been in place and the routine tests of the sirens would suggest that the population in Hawaii is largely aware of the siren. We present data from four Hawaiian Islands showing the relationship between awareness of the routine tests and interpretations of the sirens. We link this to findings from a tsunami preparedness study in Hilo, Hawaii.

  7. 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

  8. Sheet-gravel evidence for a late Holocene tsunami run-up on beach dunes, Great Barrier Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Nichol, Scott L.; Lian, Olav B.; Carter, Charles H.

    2003-01-01

    A semi-continuous sheet of granule to cobble-size clasts forms a distinctive deposit on sand dunes located on a coastal barrier in Whangapoua Bay, Great Barrier Island, New Zealand. The gravel sheet extends from the toe of the foredune to 14.3 m above mean sea level and 200 m landward from the beach. Clasts are rounded to sub-rounded and comprise lithologies consistent with local bedrock. Terrestrial sources for the gravel are considered highly unlikely due to the isolation of the dunes from hillslopes and streams. The only source for the clasts is the nearshore to inner shelf of Whangapoua Bay, where gravel sediments have been previously documented. The mechanism for transport of the gravel is unlikely to be storm surge due to the elevation of the deposit; maximum-recorded storm surge on this coast is 0.8 m above mean high water spring tide. Aeolian processes are also discounted due to the size of clasts and the elevation at which they occur. Tsunami is therefore considered the most probable mechanism for gravel transport. Minimum run-up height of the tsunami was 14.3 m, based on maximum elevation of gravel deposits. Optical ages on dune sands beneath and covering the gravel allow age bracketing to 0-4.7 ka. Within this time frame, numerous documented regional seismic and volcanic events could have generated the tsunami, notably submarine volcanism along the southern Kermadec arc to the east-southeast of Great Barrier Island where large magnitude events are documented for the late Holocene. Radiocarbon ages on shell from Maori middens that appear to have been reworked by tsunami run-up constrain the age of this event to post ca. 1400 AD. Regardless of the precise age of this event, the well-preserved nature of the Whangapoua gravel deposit provides for an improved understanding of the high degree of spatial variability in tsunami run-up.

  9. Effects of rupture complexity on local tsunami inundation: Implications for probabilistic tsunami hazard assessment

    NASA Astrophysics Data System (ADS)

    Müller, Christof; Power, William; Fraser, Stuart; Wang, Xiaoming

    2015-04-01

    We investigate the influence of earthquake source complexity on the extent of inundation caused by a resulting tsunami. We simulated 100 scenarios with sources on the Hikurangi subduction-interface in the vicinity of Hawke's Bay/Napier and Poverty Bay/Gisborne (New Zealand). For both target areas rupture complexity was found to have a first order effect on flow depth and inundation extent for the local tsunami sources investigated. The position of individual asperities in the slip distribution on the rupture interface control to some extent how severe inundation will be. However, predicting inundation extent in detail from investigating the distribution of slip on the rupture interface proves difficult. The distribution of inundation extent for one earthquake of given magnitude but different realisations of slip distribution is skewed. The extent of inundation predicted by a uniform distribution of slip on the rupture interface is roughly represented by the median of this distribution. Assuming uniform slip on the rupture interface therefore will underestimate the potential impact and extent of inundation. For example, simulation of an MW 8.7 to MW 8.8 earthquake with uniform slip reproduced the area potentially affected by inundation of an equivalent non-uniform slip event of MW 8.4 for Napier. The extent of inundation does not follow a simple monotonic relationship to the magnitude of the earthquake. Therefore de-aggregation, to establish the contribution of different sources with different slip distributions to the probabilistic hazard, cannot be performed based on magnitude considerations alone. We propose to use parameters of the tsunami wave field measured offshore as predictors for inundation severity to perform de-aggregation based on simulations with the linear wave equations.

  10. Tsunami Predictions for the Coast of Alaska Kodiak Island to Ketchikan.

    DTIC Science & Technology

    1987-04-01

    earth’s crust) appear to be the principal seismic mechanism responsible for the generation of tsunamis. Coastal and submarine landslides and volcanic...the local scattering of the tsunami wave. They may also represent some locally generated waves caused, for example, by submarine landslides induced by...the United States; Tsunamis, Seiches, and Landslide -Induced Water Waves," Miscellaneous Paper S-73-1, Report 15, US Army Engineer Waterways Experiment

  11. Public Health Needs Assessments of Tutuila Island, American Samoa, After the 2009 Tsunami

    PubMed Central

    Choudhary, Ekta; Chen, Tai-Ho; Martin, Colleen; Vagi, Sara; Roth, Joseph; Keim, Mark; Noe, Rebecca; Ponausuia, Seiuli Elisapeta; Lemusu, Siitia; Bayleyegn, Tesfaye; Wolkin, Amy

    2015-01-01

    Objective An 8.3 magnitude earthquake followed by tsunami waves devastated American Samoa on September 29, 2009, resulting in widespread loss of property and public services. An initial and a follow-up Community Needs Assessment for Public Health Emergency Response (CASPER) objectively quantified disaster-affected population needs. Methods Using a 2-stage cluster sampling method of CASPER, a household questionnaire eliciting information about medical and basic needs, illnesses, and injuries was administered. To assess response efforts, percent changes in basic and medical needs, illnesses, and injuries between the initial and follow-up CASPER were calculated. Results During the initial CASPER (N=212 households), 47.6% and 51.6% of households reported needing a tarpaulin and having no electricity, respectively. The self-reported greatest needs were water (27.8%) and financial help with cleanup (25.5%). The follow-up CASPER (N=207 households) identified increased vector problems compared to pre-tsunami, and food (26%) was identified as the self-reported greatest need. As compared to the initial CASPER, the follow-up CASPER observed decreases in electricity (−78.3%), drinking water (−44.4%), and clothing (−26.6%). Conclusion This study highlights the use of CASPER during the response and recovery phases following a disaster. The initial CASPER identified basic needs immediately after the earthquake, whereas the follow-up CASPER assessed effectiveness of relief efforts and identified ongoing community needs. PMID:23077263

  12. Ages and relative sizes of pre-2004 tsunamis in the Bay of Bengal inferred from geologic evidence in the Andaman and Nicobar Islands

    NASA Astrophysics Data System (ADS)

    Rajendran, C. P.; Rajendran, Kusala; Andrade, Vanessa; Srinivasalu, S.

    2013-04-01

    Geologic evidence along the northern part of the 2004 Aceh-Andaman rupture suggests that this region generated as many as five tsunamis in the prior 2000 years. We identify this evidence by drawing analogy with geologic records of land-level change and the tsunami in 2004 from the Andaman and Nicobar Islands (A&N). These analogs include subsided mangrove swamps, uplifted coral terraces, liquefaction, and organic soils coated by sand and coral rubble. The pre-2004 evidence varies in potency, and materials dated provide limiting ages on inferred tsunamis. The earliest tsunamis occurred between the second and sixth centuries A.D., evidenced by coral debris of the southern Car Nicobar Island. A subsequent tsunami, probably in the range A.D. 770-1040, is inferred from deposits both in A&N and on the Indian subcontinent. It is the strongest candidate for a 2004-caliber earthquake in the past 2000 years. A&N also contain tsunami deposits from A.D. 1250 to 1450 that probably match those previously reported from Sumatra and Thailand, and which likely date to the 1390s or 1450s if correlated with well-dated coral uplift offshore Sumatra. Thus, age data from A&N suggest that within the uncertainties in estimating relative sizes of paleo-earthquakes and tsunamis, the 1000 year interval can be divided in half by the earthquake or earthquakes of A.D. 1250-1450 of magnitude >8.0 and consequent tsunamis. Unlike the transoceanic tsunamis generated by full or partial rupture of the subduction interface, the A&N geology further provides evidence for the smaller-sized historical tsunamis of 1762 and 1881, which may have been damaging locally.

  13. 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.

  14. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  15. Time Evolution of Man-Made Harbour Modifications in San Diego: Effects on Tsunami Amplitudes and Currents

    NASA Astrophysics Data System (ADS)

    Barberopoulou, A.; Legg, M.; Gica, E.

    2014-12-01

    Harbors are typically modified to enhance operations and increase space in ports. Ports are usually designed to protect boats and docks against sudden vertical water fluctuations. Tsunami currents however are often ignored-current monitoring is usually not quantitative- in the design of harbor modifications. Damage from tsunami currents in ports has occurred in several recent tsunamis (Sea of Japan, 1983; Chile, 1960, 2010; Tohoku, 2011). Significant tsunami currents (>2 m/sec) often occur without substantial wave amplitudes (<1-2 meters). Because tsunami amplitudes are used as the basis to determine event "significance", the hazard from potentially strong currents may be overlooked. In order to evaluate the impact of anthropogenic effects on tsunami impact at ports, we examine the history of man-made modifications made to San Diego Bay since the late nineteenth century. Digital elevation models were created based on historic nautical charts of 1892, 1935, 1945 and at present. Tsunami simulations were conducted based on two distant events (1960 Chile and 2011 Tohoku) and two hypothetical severe local cases (San Clemente fault bend and Coronado Canyon landslide). The distant events provide historical comparisons with the model while the local events are based on offshore geology and tectonic activity. Most of the changes in San Diego Bay have included dredging, enlargement of the North Island/Coronado, widening of the Silver Strand, and creation of new marinas by enhancing already existing dunes or filling and creating breakwaters. Those changes mostly occurred during the first half of the 20th century. Post- 1965 the bay has sustained a similar appearance to the bathymetry/topography we know today. Early harbor configurations showed strong currents in the narrow channel between Point Loma and North Island/Coronado while overtopping of the narrow Silver Strand to the south occurred. The modern configuration finds increased currents at the harbor entrance and between

  16. 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

  17. Sedimentary processes associated with sand and boulder deposits formed by the 2011 Tohoku-oki tsunami at Sabusawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Goto, Kazuhisa; Sugawara, Daisuke; Ikema, Satoko; Miyagi, Toyohiko

    2012-12-01

    This paper reports on the sedimentary processes of sand and boulder deposition at Sabusawa Island, Japan as a result of the 2011 Tohoku-oki tsunami. Boulders were composed of tuffaceous rocks and sourced from an earthquake-triggered slope failure as well as concrete fragments of seawall. They were scattered over the ground surface and did not form boulder ridges, although there was some local imbrication. The boulders were deposited on top of a sand layer indicating that the latter, possibly deposited from bed load, covered the ground surface first. This sand layer probably reduced friction allowing boulders to be transported more easily than might be expected across a hard ground with a high bottom friction. Sand deposits showed landward thinning and fining features, while the boulders showed a landward coarsening (tuffaceous boulders) or a landward fining (concrete boulders), indicating that large clasts were not necessarily scattered randomly but rather might have a clast size gradient with distance inland. These features are explained by the local topographic setting that constrained the directions of incoming and returning tsunami flows. Some clasts at the inland extent of the boulder field were covered by an upward fining sand layer. This feature suggests that the boulders were deposited prior to the suspended sands, with the latter subsequently laid down before the water level dropped below the top of the boulders. Such modern investigations of the sedimentary features of various sizes of grains and clasts immediately after a tsunami provide invaluable data for the reconstruction of inundation processes.

  18. 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

  19. Altered environment and risk of malaria outbreak in South Andaman, Andaman & Nicobar Islands, India affected by tsunami disaster

    PubMed Central

    Krishnamoorthy, Kaliannagoun; Jambulingam, Purushothaman; Natarajan, R; Shriram, AN; Das, Pradeep K; Sehgal, SC

    2005-01-01

    Background Pools of salt water and puddles created by giant waves from the sea due to the tsunami that occurred on 26th December 2004 would facilitate increased breeding of brackish water malaria vector, Anopheles sundaicus. Land uplifts in North Andaman and subsidence in South Andaman have been reported and subsidence may lead to environmental disturbances and vector proliferation. This warrants a situation analysis and vector surveillance in the tsunami hit areas endemic for malaria transmitted by brackish water mosquito, An. sundaicus to predict the risk of outbreak. Methods An extensive survey was carried out in the tsunami-affected areas in Andaman district of the Andaman and Nicobar Islands, India to assess the extent of breeding of malaria vectors in the habitats created by seawater flooding. Types of habitats in relation to source of seawater inundation and frequency were identified. The salinity of the water samples and the mosquito species present in the larval samples collected from these habitats were recorded. The malaria situation in the area was also analysed. Results South Andaman, covering Port Blair and Ferrargunj sub districts, is still under the recurring phenomenon of seawater intrusion either directly from the sea or through a network of creeks. Both daily cycles of high tides and periodical spring tides continue to cause flooding. Low-lying paddy fields and fallow land, with a salinity ranging from 3,000 to 42,505 ppm, were found to support profuse breeding of An. sundaicus, the local malaria vector, and Anopheles subpictus, a vector implicated elsewhere. This area is endemic for both vivax and falciparum malaria. Malaria slide positivity rate has started increasing during post-tsunami period, which can be considered as an indication of risk of malaria outbreak. Conclusion Paddy fields and fallow land with freshwater, hitherto not considered as potential sites for An. sundaicus, are now major breeding sites due to saline water. Consequently

  20. Database of recent tsunami deposits

    USGS Publications Warehouse

    Peters, Robert; Jaffe, Bruce E.

    2010-01-01

    This report describes a database of sedimentary characteristics of tsunami deposits derived from published accounts of tsunami deposit investigations conducted shortly after the occurrence of a tsunami. The database contains 228 entries, each entry containing data from up to 71 categories. It includes data from 51 publications covering 15 tsunamis distributed between 16 countries. The database encompasses a wide range of depositional settings including tropical islands, beaches, coastal plains, river banks, agricultural fields, and urban environments. It includes data from both local tsunamis and teletsunamis. The data are valuable for interpreting prehistorical, historical, and modern tsunami deposits, and for the development of criteria to identify tsunami deposits in the geologic record.

  1. 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

    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.

  2. Observation of Magnetic Fields Generated by Tsunamis

    NASA Astrophysics Data System (ADS)

    Manoj, Chandrasekharan; Maus, Stefan; Chulliat, Arnaud

    2011-01-01

    Tsunamis produce perturbations in the Earth's magnetic field by electromagnetic induction. Recent deployments of highly accurate magnetometers and the exceptionally deep solar minimum provided ideal conditions to observe these small signals from the tsunami resulting from the strong Chilean earthquake on 27 February 2010. Magnetic observatory measurements on Easter Island, 3500 kilometers west of the epicenter, show a periodic signal of 1 nanotesla, coincident in time with recordings from the local tide gauge. The detection of these magnetic signals represents a milestone in understanding tsunami-induced electromagnetic effects.

  3. Re-thinking the Distant Tsunami Hazard to Alaska

    NASA Astrophysics Data System (ADS)

    Preller, C. C.; Petty, E. A.; Knight, W. R.; Curtis, J. C.; Albanese, S. P.

    2012-12-01

    The science of tsunami has created as many questions as it has answers for vulnerable areas like those in Alaska's coastal communities. How a tsunami might inundate is determined by a variety of event-unique factors that are difficult to accurately prepare for; near shore dynamics and local bathymetry guarantee a distinctive experience at every locality. The island of St. Paul, located in the middle of the Bering Sea, measured a significant tsunami during the Japanese event in 2011. Believing that the Aleutian Chain would minimize tsunami energy into the Bering Sea, this was an eye-opening observation. Real science gives us real answers. The only way to accurately understand the effect of a tsunami is to have a tsunami; a completely unpredictable event without a season. Over the last few years, there have been several large events. Assessing impacts from the Chilean tsunami of 2010 and the Japanese tsunami of 2011, as well as other events such as Samoa and Haiti, has offered a fine-tuning to tsunami understanding and modeling. Using observed amplitudes, tsunami history, oral stories, and improved static modeling techniques, the ability to access threat by community is becoming possible. Communities previously ranked on broad generalizations are now assessed more specifically with data and modeling, providing new insights to their threat ranking. The critical though complex task of preparedness for Alaska, the state with the most coast-line and the least road system, is expensive and difficult. Translating the potential effects to emergency managers is a vague undertaking depending on the possible scenarios considered. Our understanding, with fine tuning, is proving to be essential in our approach. The reanalysis of the distance tsunami threat determined by updated tsunami science gives local officials the opportunity to improve community preparedness and allow communities to allocate scarce resources wisely.; Japanese Tsunami measured at Saint Paul Island showing

  4. A prehistoric tsunami induced long-lasting ecosystem changes on a semi-arid tropical island--the case of Boka Bartol (Bonaire, Leeward Antilles).

    PubMed

    Engel, Max; Brückner, Helmut; Fürstenberg, Sascha; Frenzel, Peter; Konopczak, Anna Maria; Scheffers, Anja; Kelletat, Dieter; May, Simon Matthias; Schäbitz, Frank; Daut, Gerhard

    2013-01-01

    The Caribbean is highly vulnerable to coastal hazards. Based on their short recurrence intervals over the intra-American seas, high-category tropical cyclones and their associated effects of elevated storm surge, heavy wave impacts, mudslides and floods represent the most serious threat. Given the abundance of historical accounts and trigger mechanisms (strike-slip motion and oblique collision at the northern and southern Caribbean plate boundaries, submarine and coastal landslides, volcanism), tsunamis must be considered as well. This paper presents interdisciplinary multi-proxy investigations of sediment cores (grain size distribution, carbonate content, loss-on-ignition, magnetic susceptibility, microfauna, macrofauna) from Washington-Slagbaai National Park, NW Bonaire (Leeward Antilles). No historical tsunami is recorded for this island. However, an allochthonous marine layer found in all cores at Boka Bartol reveals several sedimentary criteria typically linked with tsunami deposits. Calibrated (14)C data from these cores point to a palaeotsunami with a maximum age of 3,300 years. Alternative explanations for the creation of this layer, such as inland flooding during tropical cyclones, cannot entirely be ruled out, though in recent times even the strongest of these events on Bonaire did not deposit significant amounts of sediment onshore. The setting of Boka Bartol changed from an open mangrove-fringed embayment into a poly- to hyperhaline lagoon due to the establishment or closure of a barrier of coral rubble during or subsequent to the inferred event. The timing of the event is supported by further sedimentary evidence from other lagoonal and alluvial archives on Bonaire.

  5. Paleo-tsunami and land-level change evidence from the west coast of South Andaman, Andman Nicobar Island, India

    NASA Astrophysics Data System (ADS)

    Malik, Javed; Banerjee, Chiranjib; Shishikura, M.

    2010-05-01

    The Sumatra-Andaman earthquake of December 26, 2004, Mw 9.3 provided an ideal opportunity to understand the pattern of paleoseismic event and paleo-tsunami deposition in Andaman and Nicobar Islands. The present investigation carried out along the west coast of Andaman Island around Collinpur village (N11°39´56.9´´ and E92°44´31.3´´) revealed excellent evidences pointing towards land-level change and tsunami deposition during recent historic past. Sedimentary records studied from the geo-slicer and trench sections collected along transect across stable beach ridges and swales between the ridges (N11°41'38″, E92°35'52″) revealed distinct change in depositional environments which have been attributed to tectonic activity. In total we excavated 4 trenches and collected 9 geo-slicer sections. We present here our preliminary results and interpretations. Based on sedimentary structures, grain size and nature of contact and colour, sedimentary units from the trenches and geoslicers were classified into seven units (a, b, c, d, e, f, g and h) from bottom to top. The bottom most unit a is marked by poor laminations of fine silty-sand and peaty material suggestive of inter-tidal to marshy environment. This is overlain by 30 cm thick unit b - comprising coarse sand with gravel fragments (corals, shells, rock clasts etc.) in the swale and coarse sandy deposits along with broken shells, peaty material and rip-up clasts of underlying soil on the back-limb of the beach ridge. The sharp-erosive contact with the underlying and overlying sedimentary unit, distinct variation in grain marked assorted fragments, broken shell; peaty material suggests deposition by tsunami wave during recent geological past. Overlying unit c marked by partially developed peaty layer suggests marshy environment at or above mean sea level indicative of a probable uplift (?) which occurred during Event I accompanied with tsunami waves. Unit d with finer deposits comprised of silty-clay suggests

  6. Effect of Murray ridge on the tsunami propagation from Makran subduction zone

    NASA Astrophysics Data System (ADS)

    Swapna, M.; Srivastava, Kirti

    2014-12-01

    The aseismic Murray ridge (MR) is a continuation of the Owen fracture zone which marks the boundary between the Indian and Arabian plates. Due to large variation in morphology and structure within this NE-SW trending ridge in the Arabian Sea a large variation of the bathymetry from few hundred metres to about 4000 m is seen. Observed seismicity on the ridge system is predominantly strike-slip. Tsunamis generated in the Makran subduction zone (MSZ) will propagate through the MR system due to its proximity. As the tsunami speed depends on the depth of the ocean, bathymetry plays a vital role on tsunami propagation. In this paper, the effect of tsunami propagation through the MR system is carried out with the existing bathymetry and comparing the results by removing the bathymetry. To study this phenomenon the 1945 Makran tsunami and worst possible tsunamigenic earthquakes form eastern and western MSZ are considered. The directivity of tsunami propagation with the ridge system is seen to change after crossing the MR towards the southeast direction for tsunamis generated in the eastern MSZ. For tsunami generated in the western MSZ there is no change in its directivity and is almost same as without the ridge with propagation being towards the open sea. Hence the MR not only affects the amplitude of the tsunamis but also the directionality and the arrival times.

  7. Tsunami Hazard Assessment in Guam

    NASA Astrophysics Data System (ADS)

    Arcas, D.; Uslu, B.; Titov, V.; Chamberlin, C.

    2008-12-01

    The island of Guam is located approximately 1500 miles south of Japan, in the vicinity of the Mariana Trench. It is surrounded in close proximity by three subduction zones, Nankai-Taiwan, East Philippines and Mariana Trench that pose a considerable near to intermediate field tsunami threat. Tsunami catalogues list 14 tsunamigenic earthquake with Mw≥8.0 since 1900 only in this region, (Soloviev and Go, 1974; Lander, 1993; Iida, 1984; Lander and Lowell, 2002), however the island has not been significantly affected by some of the largest far-field events of the past century, such as the 1952 Kamchatka, 1960 Chile, and the 1964 Great Alaska earthquake. An assessment of the tsunami threat to the island from both near and far field sources, using forecast tools originally developed at NOAA's Pacific Marine Environmental Laboratory (PMEL) for real-time forecasting of tsunamis is presented here. Tide gauge records from 1952 Kamchatka, 1964 Alaska, and 1960 Chile earthquakes at Apra Harbor are used to validate our model set up, and to explain the limited impact of these historical events on Guam. Identification of worst-case scenarios, and determination of tsunamigenic effective source regions are presented for five vulnerable locations on the island via a tsunami sensitivity study. Apra Harbor is the site of a National Ocean Service (NOS) tide gauge and the biggest harbor on the island. Tumon Bay, Pago Bay, Agana Bay and Inarajan Bay are densely populated areas that require careful investigation. The sensitivity study shows that earthquakes from Eastern Philippines present a major threat to west coast facing sites, whereas the Marina Trench poses the biggest concern to the east coast facing sites.

  8. Investigation of Tsunami Effects on Harbor Structures with High Resolution Tsunami Modeling: Case study in the Biggest Port of Turkey in Istanbul

    NASA Astrophysics Data System (ADS)

    Ozer Sozdinler, Ceren; Arikawa, Taro; Meral Ozel, Nurcan; Necmioglu, Ocal; Cevdet Yalciner, Ahmet; Zaytsev, Andrey; Tomita, Takashi

    2015-04-01

    Ports and harbors are critical marine transportation hubs which must survive and continue functions and operability after the disasters. Hence the recovery operations may continue without interruption. Tsunami is one of the important marine hazards and major impact of any tsunamis are observed mainly in the harbors. Therefore a complete assessment of tsunami behavior, tsunami amplification, abnormal agitation and related damage in ports and harbors is highly essential. Tsunami modeling with high resolution would be a proper approach to understand the effects of tsunamis on marine structures and harbor facilities. The tsunami mitigation plans can be developed using the results of high resolution modeling. The large scale industrial facilities of Turkey are located along the coasts of Marmara Sea in Turkey. Ambarli Port in Istanbul is known to be the biggest trade gate of Marmara region with seven different terminals and an offshore platform operated by different companies for container and cargo handling. The port is serving not only the megacity Istanbul but also the whole country. Compiling the earthquake catalogs and historical records, possible earthquake locations in Marmara Sea are used to select the tsunami source scenarios for modeling. The high resolution bathymetric and topographic data for Ambarli Port region is also another necessary data which has been constructed with a resolution of less than 4m grid size. The sensitively digitized coastline and the sea and land structures with their coordinates and heights are also included in bathy/topo data. The tsunami modeling codes NAMIDANCE and STOC-CADMAS are used for the calculations of tsunami hydrodynamic parameters as the distributions of wave amplitude, current velocity, flow depth and inundation distance. The tsunami pressure exerted onto the terminal blocks are determined by tsunami modeling consisting of three-dimensional and non-hydrostatic calculation approaches. The results of each code are

  9. Effect of tides and source location on nearshore tsunami-induced currents

    NASA Astrophysics Data System (ADS)

    Ayca, Aykut; Lynett, Patrick J.

    2016-12-01

    Here we present the results of a numerical modeling study that investigates how event-maximum tsunami-induced currents vary due to the dynamic effects of tides and wave directivity. First, analyses of tide-tsunami interaction are presented in three harbors by coupling the tsunami with the tide, and allowing the initial tsunami wave to arrive at various tidal phases. We find that tsunami-tide interaction can change the event-maximum current speed experienced in a harbor by up to 25% for the events and harbors studied, and we note that this effect is highly site-specific. Second, to evaluate the effect of wave directionality on event-maximum currents, earthquakes sources were placed throughout the Pacific, with magnitudes tuned to create the same maximum near-coast amplitude at the harbor of study. Our analysis also shows that, for the harbor and sources examined, the effect of offshore directionality and tsunami frequency content has a weak effect on the event-maximum currents experienced in the harbor. The more important dependency of event-maximum currents is the near-harbor amplitude of the wave, indicating that event-maximum currents in a harbor from a tsunami generated by a large far-field earthquake may be reasonably well predicted with only information about the predicted local maximum tsunami amplitude. This study was motivated by the hope of constructing a basis for understanding the dynamic effects of tides and wave directivity on current-based tsunami hazards in a coastal zone. The consideration of these aspects is crucial and yet challenging in the modeling of tsunami currents.

  10. Medical response of a physician and two nurses to the mass-casualty event resulting in the Phi Phi Islands from the tsunami.

    PubMed

    Ammartyothin, Surasak; Ashkenasi, Issac; Schwartz, Dagan; Leiba, Adi; Nakash, Guy; Pelts, Rami; Goldberg, Avishay; Bar-Dayan, Yaron

    2006-01-01

    The Phi Phi Islands are isolated islands located about one hour by ship from the mainland in Krabi province of Thailand. There is a small medical facility where the director is the one physician that provides care to residents and tourists. This small medical facility faced an enormous mass casualty incident due to the 2004 Tsunami. The hospital was damaged by the Tsunami wave and was not functional, one crew member died and another was injured. Medical care and evacuation posed a unique problem in the Phi Phi Islands due to remoteness, limited medical resources, lack of effective communication with the main land and the large number of victims. An alternative medical facility was located in a nearby hotel. The crew included the medical director, two nurses, two additional staff members, 10 local volunteers, and hotel staff members. The medical crew had to treat 600-700 casualties in 24 hours. Most of the victims were mildly injured, but approximately 100 (15%) of the victims could not walk due to their injuries. The medical director, made a conscious decision to initially treat only circulation ("C") problems, by controlling external hemorrhages. This decision was driven by the lack of equipment and personnel to deal with airway ("A") and breathing ("B") problems. In the post-disaster debriefing, the Phi Phi Island hospital physician noted five major lessons concerning disaster management in such extreme situation in a small facility located in a remote area: (1) effective resistant communication facilities must be ensured; (2) clear, simple "evacuation plans" should be made in advance; (3) plans should be made to ensure automatic reinforcement of remote areas with evacuation vehicles, medical equipment and medical personnel; (4) efficient cooperation with medical volunteers must be planned and drilled; and (5) every team member of such a hospital must participate in an educational program and periodic drills should be done to improve the disaster and emergency

  11. Tsunami effects at Korean Nuclear Power Plant Sites by Plate Boundary Earthquakes

    NASA Astrophysics Data System (ADS)

    Jin, Sobeom; Hyun, Seung Gyu; Bae, Jae Seok; Kim, Gun Hyeong; Yoon, Sung Bum

    2015-04-01

    Great earthquakes have occurred at the Nankai Trough due to the subduction of the Philippine Sea plate beneath Honshu, Japan. The 1707 Hoei tsunami associated with the Mw 8.7 earthquake, in particular, was the largest event generated in this area. The Nankai Trough is one of the most earthquake-prone area near Japan. And the tsunami affected to Korea according to a Korean historic literature. In this study, new hypothetical plate boundary earthquakes (Mw 9.6) ruptured simultaneously from the Nankai Trough to the Ryukyu Trench (NTRT) are proposed and applied to evaluate the tsunami effects at the Nuclear Power Plant Sites in Korea. In order to make reasonable tsunami sources the asperity model is adapted. The numerical model using the modified leap-frog finite difference scheme is employed to simulate the propagation of tsunami generated at NTRT. This numerical model considering the dispersion effect and inundation of tsunami is then employed to estimate the maximum tsunami heights. Predicted results will be used to make the measures against unexpected tsunami attacks.

  12. Indigenous knowledge management to enhance community resilience to tsunami risk: lessons learned from Smong traditions in Simeulue island, Indonesia

    NASA Astrophysics Data System (ADS)

    Rahman, A.; Sakurai, A.; Munadi, K.

    2017-02-01

    Knowledge accumulation and production embedded in communities through social interactions meant that the Smong tradition of indigenous knowledge of tsunami risk successfully alerted people to the 2004 tsunami, on the island of Simeulue, in Aceh, Indonesia. Based on this practical example, an indigenous management model was developed for Smong information. This knowledge management method involves the transformation of indigenous knowledge into applicable ways to increase community resilience, including making appropriate decisions and taking action in three disaster phases. First, in the pre-disaster stage, the community needs to be willing to mainstream and integrate indigenous knowledge of disaster risk reduction issues into related activities. Second, during disasters, the Smong tradition should make the community able to think clearly, act based on informed decisions, and protect themselves and others by using their indigenous knowledge. Last, in the post-disaster phase, the community needs to be strong enough to face challenges and support each other and “building back better” efforts, using local resources. The findings for the Smong tradition provide valuable knowledge about community resilience. Primary community resilience to disasters is strongly related to existing knowledge that triggers appropriate decisions and actions during pre-disaster, disaster, and post-disaster phases.

  13. Sedimentary Record and Morphological Effects of a Landslide-Generated Tsunami in a Polar Region: The 2000 AD Tsunami in Vaigat Strait, West Greenland

    NASA Astrophysics Data System (ADS)

    Szczucinski, W.; Rosser, N. J.; Strzelecki, M. C.; Long, A. J.; Lawrence, T.; Buchwal, A.; Chague-Goff, C.; Woodroffe, S.

    2012-12-01

    To date, the effects of tsunami erosion and deposition have mainly been reported from tropical and temperate climatic zones yet tsunamis are also frequent in polar zones, particularly in fjord settings where they can be generated by landslides. Here we report the geological effects of a landslide-triggered tsunami that occurred on 21st November 2000 in Vaigat, northern Disko Bugt in west Greenland. To characterise the typical features of this tsunami we completed twelve detailed coastal transects in a range of depositional settings: cliff coasts, narrow to moderate width coastal plains, lagoons and a coastal lake. At each setting we completed a detailed map using a laser scanner and DGPS survey. The tsunami deposits were described from closely spaced trenches and, from the lake, by a series of sediment cores . At each setting we examined the sedimentological properties of the deposits, as well as their bulk geochemistry and diatom content. Selected specimens of arctic willow from inundated and non-inundated areas were collected to assess the impact of the event in their growth ring records. Samples of sediments beneath the AD 2000 deposit were studied for 137Cs to confirm the age of the tsunami and to assess the extent of erosion. Offshore sediment samples, modern beach and soils/sediments underlying the AD 2000 tsunami deposits were sampled to determine tsunami deposit sources. The observed tsunami run-up exceeded 20 m next to the tsunami trigger - a rock avalanche at Paatuut - and up to 10 m on the opposite coast of the fjord. The inland inundation distance ranged from several tens of meters to over 300 m. The wave was recorded as far as 180 km away from the source. The tsunami inundated the coast obliquely to the shoreline in all locations studied. The tsunami frequently caused erosion of existing beach ridges whilst erosional niches were formed inland. The tsunami deposits mainly comprise gravels and very coarse sand. They are over 30 cm thick close to the

  14. 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.

  15. The 1755 tsunami propagation in Atlantics and its effects on the French West Indies

    NASA Astrophysics Data System (ADS)

    Pelinovsky, E.; Zahibo, N.; Yalciner, A.; Zaitsev, A.; Talipova, T.; Chernov, A.; Insel, I.; Dilmen, D.; Ozer, C.; Nikolkina, I.

    2009-04-01

    The present study examines the propagation of tsunami waves generated by the 1755 Lisbon earthquake in the Atlantic Ocean and its effects on the coasts of the French West Indies in the Caribbean Sea. Historical data of tsunami manifestation in the French West Indies are briefly reproduced. The mathematical model named NAMI DANCE which solves the shallow-water equations has been applied in the computations. Three possible seismic source alternatives of the tsunami source are selected for 1755 event in the simulations. The results obtained from the simulations demonstrate that the directivity of tsunami energy is divided into two strong beams directed to the southern part of North America (Florida, the Bahamas) and to the northern part of South America (Brazil). The tsunami waves reach the Lesser Antilles in 7 hrs. The computed distribution of tsunami wave height along the coasts of Guadeloupe and Martinique are presented. Calculated maximum of wave amplitudes reached 2 m in Guadeloupe and 1.5 m in Martinique. These results are also in agreement with observed data (1.8 - 3 m). The experience and data obtained in this study show that transatlantic events must also be considered in the tsunami hazard assessment and development of mitigation strategies for the French West Indies.

  16. Cognitive Constraints and Island Effects

    PubMed Central

    Hofmeister, Philip; Sag, Ivan A.

    2012-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that non-structural manipulations that leave island structures intact can radically alter judgments of island violations. We argue here, building on work by Deane, Kluender, and others, that processing factors have the potential to account for this otherwise unexplained variation in acceptability judgments. We report the results of self-paced reading experiments and controlled acceptability studies which explore the relationship between processing costs and judgments of acceptability. In each of the three self-paced reading studies, the data indicate that the processing cost of different types of island violations can be significantly reduced to a degree comparable to that of non-island filler-gap constructions by manipulating a single non-structural factor. Moreover, this reduction in processing cost is accompanied by significant improvements in acceptability. This evidence favors the hypothesis that island-violating constructions involve numerous processing pressures that aggregate to drive processing difficulty above a threshold so that a perception of unacceptability ensues. We examine the implications of these findings for the grammar of filler-gap dependencies.* PMID:22661792

  17. The Effects on Tsunami Hazard Assessment in Chile of Assuming Earthquake Scenarios with Spatially Uniform Slip

    NASA Astrophysics Data System (ADS)

    Carvajal, Matías; Gubler, Alejandra

    2016-12-01

    We investigated the effect that along-dip slip distribution has on the near-shore tsunami amplitudes and on coastal land-level changes in the region of central Chile (29°-37°S). Here and all along the Chilean megathrust, the seismogenic zone extends beneath dry land, and thus, tsunami generation and propagation is limited to its seaward portion, where the sensitivity of the initial tsunami waveform to dislocation model inputs, such as slip distribution, is greater. We considered four distributions of earthquake slip in the dip direction, including a spatially uniform slip source and three others with typical bell-shaped slip patterns that differ in the depth range of slip concentration. We found that a uniform slip scenario predicts much lower tsunami amplitudes and generally less coastal subsidence than scenarios that assume bell-shaped distributions of slip. Although the finding that uniform slip scenarios underestimate tsunami amplitudes is not new, it has been largely ignored for tsunami hazard assessment in Chile. Our simulations results also suggest that uniform slip scenarios tend to predict later arrival times of the leading wave than bell-shaped sources. The time occurrence of the largest wave at a specific site is also dependent on how the slip is distributed in the dip direction; however, other factors, such as local bathymetric configurations and standing edge waves, are also expected to play a role. Arrival time differences are especially critical in Chile, where tsunamis arrive earlier than elsewhere. We believe that the results of this study will be useful to both public and private organizations for mapping tsunami hazard in coastal areas along the Chilean coast, and, therefore, help reduce the risk of loss and damage caused by future tsunamis.

  18. 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.

  19. Statistical Analysis of Tsunami Variability

    NASA Astrophysics Data System (ADS)

    Zolezzi, Francesca; Del Giudice, Tania; Traverso, Chiara; Valfrè, Giulio; Poggi, Pamela; Parker, Eric J.

    2010-05-01

    The purpose of this paper was to investigate statistical variability of seismically generated tsunami impact. The specific goal of the work was to evaluate the variability in tsunami wave run-up due to uncertainty in fault rupture parameters (source effects) and to the effects of local bathymetry at an individual location (site effects). This knowledge is critical to development of methodologies for probabilistic tsunami hazard assessment. Two types of variability were considered: • Inter-event; • Intra-event. Generally, inter-event variability refers to the differences of tsunami run-up at a given location for a number of different earthquake events. The focus of the current study was to evaluate the variability of tsunami run-up at a given point for a given magnitude earthquake. In this case, the variability is expected to arise from lack of knowledge regarding the specific details of the fault rupture "source" parameters. As sufficient field observations are not available to resolve this question, numerical modelling was used to generate run-up data. A scenario magnitude 8 earthquake in the Hellenic Arc was modelled. This is similar to the event thought to have caused the infamous 1303 tsunami. The tsunami wave run-up was computed at 4020 locations along the Egyptian coast between longitudes 28.7° E and 33.8° E. Specific source parameters (e.g. fault rupture length and displacement) were varied, and the effects on wave height were determined. A Monte Carlo approach considering the statistical distribution of the underlying parameters was used to evaluate the variability in wave height at locations along the coast. The results were evaluated in terms of the coefficient of variation of the simulated wave run-up (standard deviation divided by mean value) for each location. The coefficient of variation along the coast was between 0.14 and 3.11, with an average value of 0.67. The variation was higher in areas of irregular coast. This level of variability is

  20. Tsunamis and meteorological tsunamis: similarities and differences

    NASA Astrophysics Data System (ADS)

    Rabinovich, A. B.; Monserrat, S.

    2003-04-01

    Destructive seiche oscillations occasionally generated in certain bays and inlets are mainly associated with two natural forcing phenomena: Seismic activity (tsunamis), and atmospheric disturbances (meteotsunamis). Despite their different origin, both types are modified and amplified by topography in a similar way and produce similar catastrophic effects in coastal areas. Due to these similarities, it is often difficult to distinguish between these two phenomena without knowing the exact source characteristics. Recognition and separation of these phenomena is important for the revision/improvement of existing tsunami catalogues but also to better understand the generation mechanism and mitigate their possible catastrophic effects. To investigate this problem and to compare seismic and meteorological tsunamis, we assembled a number of cases when both phenomena had been recorded at the same place. In particular, our findings included Alicante (Mediterranean coast of Spain), Malokurilsk and Krabovaya bays (Shikotan Island, Russia), and Tofino, Winter Harbour, Bamfield, Port Hardy, and Victoria (British Columbia, Canada). We also used the results of the LAST-97 hydrophysical experiment when eight bottom pressure stations were deployed on the shelf and in the inlets of Menorca Island (Western Meditterranean, Spain) and three precise microbarographs were working on the coast. Our analysis is based on the assumption that both tsunamis and meteotsunamis are formed by the combined effects of external forcing and topography. So, for different events recorded at the same site, the similarities are related to topography and the differences to the forcing. On the contrary, for the same event recorded at different stations, similarities are mainly associated with the forcing and the differences with specific local topographic features. Analysis of the spectral distributions and comparison with background noise enabled us to reconstruct the topographic transfer functions for all

  1. Application of a Tsunami Warning Message Metric to refine NOAA NWS Tsunami Warning Messages

    NASA Astrophysics Data System (ADS)

    Gregg, C. E.; Johnston, D.; Sorensen, J.; Whitmore, P.

    2013-12-01

    In 2010, the U.S. National Weather Service (NWS) funded a three year project to integrate social science into their Tsunami Program. One of three primary requirements of the grant was to make improvements to tsunami warning messages of the NWS' two Tsunami Warning Centers- the West Coast/Alaska Tsunami Warning Center (WCATWC) in Palmer, Alaska and the Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawaii. We conducted 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) to qualitatively asses information needs in tsunami warning messages using WCATWC tsunami messages for the March 2011 Tohoku earthquake and tsunami event. 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 and Formatting and Receiver Characteristics. A 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. Using findings from this project and findings from a parallel NWS Warning Tiger Team study led by T. Nicolini, the WCATWC implemented the first of two phases of revisions to their warning messages in November 2012. A second phase of additional changes, which will fully implement the redesign of messages based on the metric, is in progress. The resulting messages will reflect current state-of-the-art knowledge on warning message effectiveness. Here we present the message metric; evidence-based rational for message factors; and examples of previous, existing and proposed messages.

  2. Wave characteristic and morphologic effects on the onshore hydrodynamic response of tsunamis

    USGS Publications Warehouse

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

    2011-01-01

    While the destruction caused by a tsunami can vary significantly owing to near- and onshore controls, we have only a limited quantitative understanding of how different local parameters influence the onshore response of tsunamis. Here, a numerical model based on the non-linear shallow water equations is first shown to agree well with analytical expressions developed for periodic long waves inundating over planar slopes. More than 13,000 simulations are then conducted to examine the effects variations in the wave characteristics, bed slopes, and bottom roughness have on maximum tsunami run-up and water velocity at the still water shoreline. While deviations from periodic waves and planar slopes affect the onshore dynamics, the details of these effects depend on a combination of factors. In general, the effects differ for breaking and non-breaking waves, and are related to the relative shift of the waves along the breaking–non-breaking wave continuum. Variations that shift waves toward increased breaking, such as steeper wave fronts, tend to increase the onshore impact of non-breaking waves, but decrease the impact of already breaking waves. The onshore impact of a tsunami composed of multiple waves can be different from that of a single wave tsunami, with the largest difference occurring on long, shallow onshore topographies. These results demonstrate that the onshore response of a tsunami is complex, and that using analytical expressions derived from simplified conditions may not always be appropriate.

  3. Tsunami overview.

    PubMed

    Morrow, Robert C; Llewellyn, D Mark

    2006-10-01

    Historically, floods and tsunamis have caused relatively few severe injuries; an exception to that tendency followed the great Andaman Island-Sumatra earthquake and tsunami of 2004. More than 280,000 people died, the coastal plains were massively scoured, and more than 1 million individuals were made homeless by the quake and resulting tsunami, which affected a 10-nation region around the Indian Ocean. This destruction overwhelmed local resources and called forth an unprecedented, prolonged, international response. The USNS Mercy deployed on a unique mission and rendered service to the people and government of Indonesia. This introduction provides background on the nature and extent of the damage, conditions upon arrival of the hospital ship 5 weeks after the initial destruction, and the configuration of professionals aboard (officers and sailors of the U.S. Navy, civilian volunteers from Project HOPE, officers of the U.S. Public Health Service, and officers and civilian mariners of the Military Sealift Command). Constraints on the mission provide context for the other articles of this issue that document and comment on the activities, challenges, methods, and accomplishments of this unique mission's "team of teams," performing humanitarian assistance and disaster relief in the Pacific theater.

  4. An effective absorbing boundary condition for linear long-wave and linear dispersive-wave tsunami simulations

    NASA Astrophysics Data System (ADS)

    Maeda, Takuto; Tsushima, Hiroaki; Furumura, Takashi

    2016-04-01

    We numerically simulated the propagation of tsunami waves with finite difference methods by using perfectly matched layer (PML) boundary conditions to effectively eliminate artificial reflections from model boundaries. The PML method damps the tsunami height and velocity of seawater only in directions perpendicular to the boundary. Although the additional terms required to implement the PML conditions make the use of the PML technique difficult for linear dispersive tsunami waves, we have proposed an empirical extension of the PML method for modeling dispersive tsunami waves. Even for heterogeneous, realistic bathymetries, numerical tests demonstrated that the PML boundary condition dramatically decreased artificial reflections from model boundaries compared to the use of traditional boundary conditions. The use of PML boundary conditions for numerical modeling of tsunamis is especially useful because it facilitates use of the later phases of tsunamis that would otherwise be compromised by artifacts caused by reflections from model boundaries.

  5. Source and significance of pumices in tsunami deposits: examples from Tenerife (Canary Islands), Santorini (Greece) and Krakatau (Indonesia) volcanoes.

    NASA Astrophysics Data System (ADS)

    Paris, R.; Nauret, F.

    2014-12-01

    Volcanic eruptions are quite often associated with tsunamis, and particularly caldera-forming eruptions near the coasts (e.g. Santorini, Krakatau, Aniakchak, Kikai). The main tsunamigenic processes are the entrance of massive pyroclastic flows in water, and flank instability, even if other processes might be involved (e.g. explosions). Fresh tephras are often preserved in sedimentary deposits left inland by tsunamis associated with volcanic eruptions. We review the different sources and incorporation mechanisms of pumices in tsunami deposits, and their significance in terms of volcanic processes, hydrodynamic processes (tsunami inundation) and their possible interactions. Three examples are adressed: the Krakatau 1883 eruption, the Minoan Thera eruption, and the El Abrigo eruption / Teno tsunami in Tenerife.

  6. The 29 September 2009 Samoa Islands Tsunami: Simulations Based on the First Focal Mechanism Solutions and Implications on Tsunami Early Warning Strategies

    NASA Astrophysics Data System (ADS)

    Tonini, Roberto; Armigliato, Alberto; Tinti, Stefano

    2011-06-01

    The tsunamigenic earthquake (Mw = 8.1) that occurred on 29 September 2009 at 17:48 UTC offshore of the Samoa archipelago east of the Tonga trench represents an example of the so-called "outer-rise" earthquakes. The areas most affected were the south coasts of Western and American Samoa, where almost 200 people were killed and run-up heights were measured in excess of 5 m at several locations along the coast. Moreover, tide gauge records showed a maximum peak-to-peak height of about 3.5 m near Pago Pago (American Samoa) and of 1.5 m offshore of Apia (Western Samoa). In this work, different fault models based on the focal mechanism solutions proposed by Global CMT and by USGS immediately after the 2009 Samoan earthquake are tested by comparing the near-field recorded signals (three offshore DART buoys and two coastal tide gauges) and the synthetic signals provided by the numerical simulations. The analysis points out that there are lights and shadows, in the sense that none of the computed tsunamis agrees satisfactorily with all the considered signals, although some of them reproduce some of the records quite well. This "partial agreement" and "partial disagreement" are analysed in the perspective of tsunami forecast and of Tsunami Early Warning System strategy.

  7. Tsunami Generation from Asteroid Airburst and Ocean Impact and Van Dorn Effect

    NASA Technical Reports Server (NTRS)

    Robertson, Darrel

    2016-01-01

    Airburst - In the simulations explored energy from the airburst couples very weakly with the water making tsunami dangerous over a shorter distance than the blast for asteroid sizes up to the maximum expected size that will still airburst (approx.250MT). Future areas of investigation: - Low entry angle airbursts create more cylindrical blasts and might couple more efficiently - Bursts very close to the ground will increase coupling - Inclusion of thermosphere (>80km altitude) may show some plume collapse effects over a large area although with much less pressure center dot Ocean Impact - Asteroid creates large cavity in ocean. Cavity backfills creating central jet. Oscillation between the cavity and jet sends out tsunami wave packet. - For deep ocean impact waves are deep water waves (Phase speed = 2x Group speed) - If the tsunami propagation and inundation calculations are correct for the small (<250MT) asteroids in these simulations where they impact deep ocean basins, the resulting tsunami is not a significant hazard unless particularly close to vulnerable communities. Future work: - Shallow ocean impact. - Effect of continental shelf and beach profiles - Tsunami vs. blast damage radii for impacts close to populated areas - Larger asteroids below presumed threshold of global effects (Ø200 - 800m).

  8. Improvement of effectiveness of existing Casuarina equisetifolia forests in mitigating tsunami damage.

    PubMed

    Samarakoon, M B; Tanaka, Norio; Iimura, Kosuke

    2013-01-15

    Coastal vegetation can play a significant role in reducing the severity of a tsunami because the energy associated with the tsunami is dissipated when it passes through coastal vegetation. Field surveys were conducted on the eastern coastline of Sri Lanka to investigate which vegetation species are effective against a tsunami and to evaluate the effectiveness of existing Casuarina equisetifolia forests in tsunami mitigation. Open gaps in C. equisetifolia forests were identified as a disadvantage, and introduction of a new vegetation belt in front or back of the existing C. equisetifolia forest is proposed to reduce the disadvantages of the open gap. Among the many plant species encountered during the field survey, ten species were selected as effective for tsunami disaster mitigation. The selection of appropriate vegetation for the front or back vegetation layer was based on the vegetation thickness per unit area (dN(u)) and breaking moment of each species. A numerical model based on two-dimensional nonlinear long-wave equations was applied to explain the present situation of open gaps in C. equisetifolia forests, and to evaluate the effectiveness of combined vegetation systems. The results of the numerical simulation for existing conditions of C. equisetifolia forests revealed that the tsunami force ratio (R = tsunami force with vegetation/tsunami force without vegetation) was 1.4 at the gap exit. The species selected for the front and back vegetation layers were Pandanus odoratissimus and Manilkara hexandra, respectively. A numerical simulation of the modified system revealed that R was reduced to 0.7 in the combined P. odoratissimus and C. equisetifolia system. However, the combination of C. equisetifolia and M. hexandra did not effectively reduce R at the gap exit. Therefore, P. odoratissimus as the front vegetation layer is proposed to reduce the disadvantages of the open gaps in existing C. equisetifolia forests. The optimal width of P. odoratissimus (W(1

  9. Predecessors of the 2004 Indian Ocean Tsunami: Inferences Based on Historical, Archeological and Geological Evidence From the Indian Coast and the Andaman-Nicobar Islands

    NASA Astrophysics Data System (ADS)

    Rajendran, C.; Rajendran, K.; Machado, T.

    2007-12-01

    The 2004 tsunami is an unprecedented event in the Indian Ocean. Never in the recent or distant history of the region has such a transoceanic event of devastating proportion is known to have been reported. Obviously, apparent lack of historical references in the culturally ancient Southeast Asian region suggests rarity of such events. Therefore, a major question that has been posed since the 2004 tsunami is whether similar events have occurred in the region in the past. If there are predecessors, what is the frequency of such events? Resolving this question is of crucial importance in developing the recurrence history of megathrust earthquakes and assessing the tsunami hazard of the region. Our strategy has been to tackle this problem using historical and archeological data, combined with geological investigations in the affected regions of the Indian coast, including the Andaman- Nicobar Islands. Citations from south India on ancient tsunami include classic Tamil texts, which mention about a devastating sea surge around A.D. 950 in the southeastern coast of India. Our studies were focused on two ancient port cities on the east coast of India: Mammallapuram and Kaveripattinam, the latter being a major township during the first millennium. The 2004 tsunami had scoured Mammallapuram beach exposing the basements of older temples. We have identified a discordant sand deposit sandwiched between two bricklayers at a site where the ruins of different generations of temples have been excavated. The radiocarbon dates suggest that this was deposited during 955+/-30 yr B.P., close to the historically documented period of devastation of this site by a sea surge. Excavations at Kaveripattinam, located 200 km to the south, revealed a widely distributed occupation horizon of A.D. 8-10 century, marked by a superjacent sand layer. We suspect that this layer represents the A.D. 950- sea incursion mentioned in the in the classic Tamil texts, also in line with the archeological

  10. The 'tsunami earthquake' of 1932 June 22 in Manzanillo, Mexico: seismological study and tsunami simulations

    NASA Astrophysics Data System (ADS)

    Okal, Emile A.; Borrero, José C.

    2011-12-01

    We conduct a detailed seismological study of the large Colima, Mexico earthquake of 1932 June 3 and of its aftershocks of June 18 and 22. The latter (Event III) generated a tsunami more devastating than that of the main shock despite much smaller seismic magnitudes, thus qualifying as a so-called 'tsunami earthquake'. Relocation based on published arrival times shows that Event III took place up-dip of the main shock. The analysis of the spectral amplitude of mantle surface waves yields low-frequency moments of 24, 5.2 and 4 times 1027 dyn cm, respectively, with Event III featuring a moment growing with period, which expresses the source slowness characteristic of 'tsunami earthquakes'. This is confirmed by a deficient energy-to-moment ratio, as derived from high-frequency P waves recorded at Pasadena. Near-field hydrodynamic simulations show that the effects of the main shock's tsunami are well modelled by a standard seismic source, whereas the stronger tsunami from Event III can be modelled by rupture along a splay fault in a mechanically deficient material. All our results then fit the model for 'tsunami earthquake' aftershocks proposed for the Kuril Islands by Fukao in 1979.

  11. Tsunami currents in ports.

    PubMed

    Borrero, Jose C; Lynett, Patrick J; Kalligeris, Nikos

    2015-10-28

    Tsunami-induced currents present an obvious hazard to maritime activities and ports in particular. The historical record is replete with accounts from ship captains and harbour masters describing their fateful encounters with currents and surges caused by these destructive waves. Despite the well-known hazard, only since the trans-oceanic tsunamis of the early twenty-first century (2004, 2010 and 2011) have coastal and port engineering practitioners begun to develop port-specific warning and response products that accurately assess the effects of tsunami-induced currents in addition to overland flooding and inundation. The hazard from strong currents induced by far-field tsunami remains an underappreciated risk in the port and maritime community. In this paper, we will discuss the history of tsunami current observations in ports, look into the current state of the art in port tsunami hazard assessment and discuss future research trends.

  12. The growth of Ritter Island volcano, Papua New Guinea, and the lateral collapse landslide and tsunami of 1888: new insights from eyewitness accounts

    NASA Astrophysics Data System (ADS)

    Ray, Melanie Jane; Day, Simon; Downes, Hilary

    2014-05-01

    We present a case study of the 1888 edifice lateral collapse landslide and tsunami event at Ritter Island volcano, using a more complete set of primary and secondary eyewitness accounts than has been used in previous studies. The collapse, early in the morning of March 13th, 1888, removed most of the island and its western submarine flank down to the base of the edifice some 900 m below sea level. The resulting tsunami is believed to have eradicated entire coastal communities on the surrounding islands and was recorded by German colonists in several locations around the Bismarck Sea and on adjacent coasts. Our analysis, based in particular upon new and complete translation of the German accounts, considers the evolution of the island over the previous two centuries and the events of March 1888, with the aim of clarifying the constraints that exist upon the cause, kinematics and mechanisms of the lateral collapse. Our analysis indicates that the pre-collapse Ritter edifice produced frequent strombolian eruptions and steam emissions, building an approximately 1700 m wide, notably steep-sided edifice with a N-S elongated oval shape in plan, by the late 1800s. Most activity was concentrated at a group of summit craters some 800 m above sea level, possibly also in a north-south line, with lesser flank fissure activity. The accounts of the tsunami indicate that the 1888 collapse involved a single large-scale catastrophic landslide, but descriptions of the island in the following days indicate a period in which there were many small landslides from the newly formed and unstable collapse scar. There is no evidence for a sequence of large landslides during this event and there is no clear evidence for a coincident or causal magmatic explosive eruption. One report suggests that there was activity (perhaps phreatic or phreatomagmatic explosions?) prior to the collapse that lead some of the resident local communities to seek higher ground, but evidence for precursory flank

  13. 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.

  14. Geomorphic and stratigraphic evidence for an unusual tsunami or storm a few centuries ago at Anegada, British Virgin Islands

    USGS Publications Warehouse

    Atwater, Brian F.; ten Brink, Uri S.; Buckley, Mark; Halley, Robert S.; Jaffe, Bruce E.; López-Venegas, Alberto M.; Reinhardt, Eduard G.; Tuttle, Maritia P.; Watt, Steve; Wei, Yong

    2012-01-01

    directly by washing sand into former inlets, or indirectly by reducing the tidal prism or supplying sand to post-overwash currents and waves. The overwash happened after A.D. 1650 if coeval with radiocarbon-dated leaves in the mud cap, and it probably happened before human settlement in the last decades of the 1700s. A prior overwash event is implied by an inland set of breaches. Hypothetically, the overwash in 1650–1800 resulted from the Antilles tsunami of 1690, the transatlantic Lisbon tsunami of 1755, a local tsunami not previously documented, or a storm whose effects exceeded those of Hurricane Donna, which was probably at category 3 as its eye passed 15 km to Anegada’s south in 1960.

  15. Paleoclimate Reconstruction during the 17th to 18th Century Using Fossil Coral Tsunami Boulders from Ishigaki Island, the Ryukyus, Japan

    NASA Astrophysics Data System (ADS)

    Tsuzuki, K.; Yokoyama, Y.; Seki, A.; Kawakubo, Y.; Araoka, D.; Suzuki, A.

    2014-12-01

    Little Ice Age (LIA) which lasted during approximately 1450 to 1850 (e.g. Grove, 1988) is known as naturally occurring climate fluctuation, so knowing LIA in detail is necessary to improve climate models. Instrumental records can only extend back to about 100 years in many areas, thus paleoclimate records are reconstructed using proxies in tree rings, sediments and so force. However there are differences in reconstructed timings and magnitudes of LIA occurred in each area (Overpack et al., 1997), and most of the records are based mainly on terrestrial proxies such as tree ring records, whereas only limited numbers of marine records are available (Mann et al., 2008). Coral skeletal climatology is a useful tool to reconstruct marine paleoclimate records in tropics and subtropics. Hermatypic corals, Porites spp. have aragonite skeletons and they have annual bands, which are suitable to reconstruct high-resolution paleoclimate in seasonal scale by measuring chemical compositions. Skeletal Sr/Ca ratio in Porites spp. has been widely used as a reliable proxy of SST (Sea Surface Temperature). However, corals grow for approximately several decades to 200 years, hence it is difficult to reconstruct LIA paleoclimate using living corals. Cobb et al. (2003) used fossil corals casted on shore by storms to reconstruct millennial scale paleoclimate. There are fossil coral boulders in the eastern coast of Ishigaki Island, Ryukyus, Japan. These fossil coral boulders were casted on shore by paleo Tsunami events, thus they are called "Tsunami boulders" (Araoka et al., 2010). Fossil corals used by Cobb et al. have 30-90-year records while some large Tsunami boulders have multi-centennial continuous records. In this study, we reconstruct paleo SST using the Tsunami boulder from Ishigaki Island. The boulder has 185 years of annual banding. U-series dating shows the boulder was moved on shore at Meiwa earthquake in 1771. We measure Sr/Ca ratio using LA-HR-ICPMS (Laser Ablation High

  16. The December 26, 2004, tsunami on Sumatra Island as a source of internal gravity waves in the earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Mikhailova, G. A.; Mikhailov, Yu. M.; Kapustina, O. V.

    2016-09-01

    Records of the coastal mareographs during the December 26, 2004, tsunami are used to study the fine structure of the tsunami wave power spectra. It is shown that a series of maxima is observed in their spectra near the source in a range of internal gravity wave frequencies of 0.2-1.2 mHz, which coincides with the frequencies of the natural oscillations of the Earth. This experimental finding enables us to propose a possible physical mechanism for the formation of tsunami waves as a result of oscillations in the sea bottom at these frequencies. Internal gravity waves in the Earth's atmosphere excited in this way are found in the variations of the total electron content that resulted from this powerful earthquake.

  17. Geological effects and implications of the 2010 tsunami along the central coast of Chile

    USGS Publications Warehouse

    Morton, R.A.; Gelfenbaum, G.; Buckley, M.L.; Richmond, B.M.

    2011-01-01

    Geological effects of the 2010 Chilean tsunami were quantified at five near-field sites along a 200. km segment of coast located between the two zones of predominant fault slip. Field measurements, including topography, flow depths, flow directions, scour depths, and deposit thicknesses, provide insights into the processes and morphological changes associated with tsunami inundation and return flow. The superposition of downed trees recorded multiple strong onshore and alongshore flows that arrived at different times and from different directions. The most likely explanation for the diverse directions and timing of coastal inundation combines (1) variable fault rupture and asymmetrical slip displacement of the seafloor away from the epicenter with (2) resonant amplification of coastal edge waves. Other possible contributing factors include local interaction of incoming flow and return flow and delayed wave reflection by the southern coast of Peru. Coastal embayments amplified the maximum inundation distances at two sites (2.4 and 2.6. km, respectively). Tsunami vertical erosion included scour and planation of the land surface, inundation scour around the bases of trees, and channel incision from return flow. Sheets and wedges of sand and gravel were deposited at all of the sites. Locally derived boulders up to 1. m in diameter were transported as much as 400. m inland and deposited as fields of dispersed clasts. The presence of lobate bedforms at one site indicates that at least some of the late-stage sediment transport was as bed load and not as suspended load. Most of the tsunami deposits were less than 25. cm thick. Exceptions were thick deposits near open-ocean river mouths where sediment supply was abundant. Human alterations of the land surface at most of the sites provided opportunities to examine some tsunami effects that otherwise would not have been possible, including flow histories, boulder dispersion, and vegetation controls on deposit thickness

  18. Investigation of Hydrodynamic Parameters and the Effects of Breakwaters During the 2011 Great East Japan Tsunami in Kamaishi Bay

    NASA Astrophysics Data System (ADS)

    Ozer Sozdinler, Ceren; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Suppasri, Anawat; Imamura, Fumihiko

    2015-12-01

    The March 2011 Great East Japan Tsunami was one of the most disastrous tsunami events on record, affecting the east coast of Japan to an extreme degree. Extensive currents combined with flow depths in inundation zones account for this devastating impact. Video footage taken by the eyewitnesses reveals the destructive effect and dragging capability of strong tsunami currents along the coast. This study provides a numerical modeling study in Kamaishi Bay, calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the Froude number Fr 2 ; and also other calculated hydrodynamic parameters, such as the distribution of instantaneous flow depths, maximum currents and water surface elevations that occurred during this catastrophic tsunami. Analyses were performed by using the tsunami numerical modeling code NAMI DANCE with nested domains at a higher resolution. The effect of the Kamaishi breakwater on the tsunami inundation distance and coastal damage was tested by using the conditions of "with breakwater," "without breakwater," and "damaged breakwater." Results show that the difference between the hydrostatic pressure on the seaward side of the breakwater and the leeward side of the breakwater is quite high, clarifying conditions contributing to failure of the breakwater. Lower water surface elevations were calculated in the case of a breakwater existing at the entrance, a partly valid condition for the damaged breakwater case. The results are different for current velocities and Fr_{max}2 in the "with breakwater" condition due to the concentration of energy through the breakwater gaps.

  19. Microbial Ecology of Thailand Tsunami and Non-Tsunami Affected Terrestrials

    PubMed Central

    Somboonna, Naraporn; Wilantho, Alisa; Jankaew, Kruawun; Assawamakin, Anunchai; Sangsrakru, Duangjai; Tangphatsornruang, Sithichoke; Tongsima, Sissades

    2014-01-01

    The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1), as well as a parallel unaffected terrestrial site, non-tsunami affected (S2). S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species. PMID:24710002

  20. Microbial ecology of Thailand tsunami and non-tsunami affected terrestrials.

    PubMed

    Somboonna, Naraporn; Wilantho, Alisa; Jankaew, Kruawun; Assawamakin, Anunchai; Sangsrakru, Duangjai; Tangphatsornruang, Sithichoke; Tongsima, Sissades

    2014-01-01

    The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1), as well as a parallel unaffected terrestrial site, non-tsunami affected (S2). S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species.

  1. 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

  2. Tsunami Preparedness

    MedlinePlus

    ... water. Fact Occasionally, tsunamis can form walls of water (known as tsunami bores) but tsunamis normally have the appearance of a fast-rising and fast-receding flood. They can be similar to a tide cycle occurring in just 10 to 60 minutes instead ...

  3. 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.

  4. Tsunami Forecasting in the Atlantic Basin

    NASA Astrophysics Data System (ADS)

    Knight, W. R.; Whitmore, P.; Sterling, K.; Hale, D. A.; Bahng, B.

    2012-12-01

    The mission of the West Coast and Alaska Tsunami Warning Center (WCATWC) is to provide advance tsunami warning and guidance to coastal communities within its Area-of-Responsibility (AOR). Predictive tsunami models, based on the shallow water wave equations, are an important part of the Center's guidance support. An Atlantic-based counterpart to the long-standing forecasting ability in the Pacific known as the Alaska Tsunami Forecast Model (ATFM) is now developed. The Atlantic forecasting method is based on ATFM version 2 which contains advanced capabilities over the original model; including better handling of the dynamic interactions between grids, inundation over dry land, new forecast model products, an optional non-hydrostatic approach, and the ability to pre-compute larger and more finely gridded regions using parallel computational techniques. The wide and nearly continuous Atlantic shelf region presents a challenge for forecast models. Our solution to this problem has been to develop a single unbroken high resolution sub-mesh (currently 30 arc-seconds), trimmed to the shelf break. This allows for edge wave propagation and for kilometer scale bathymetric feature resolution. Terminating the fine mesh at the 2000m isobath keeps the number of grid points manageable while allowing for a coarse (4 minute) mesh to adequately resolve deep water tsunami dynamics. Higher resolution sub-meshes are then included around coastal forecast points of interest. The WCATWC Atlantic AOR includes eastern U.S. and Canada, the U.S. Gulf of Mexico, Puerto Rico, and the Virgin Islands. Puerto Rico and the Virgin Islands are in very close proximity to well-known tsunami sources. Because travel times are under an hour and response must be immediate, our focus is on pre-computing many tsunami source "scenarios" and compiling those results into a database accessible and calibrated with observations during an event. Seismic source evaluation determines the order of model pre

  5. Large-Amplitude, Scattered Tsunami Wave Mapping Enabled by Ocean Bottom Seismometer Array Recordings

    NASA Astrophysics Data System (ADS)

    Shi, J.; Kohler, M. D.; Ampuero, J. P.; Sutton, J.

    2015-12-01

    A deployment of ocean bottom seismometers off the coast of southern California recorded the March 2011 Tohoku tsunami on 22 differential pressure gauges (DPGs). The DPG tsunami records across the entire array show multiple large-amplitude, coherent phases arriving one hour to more than 36 hours after the initial tsunami phase. Analysis of the DPG recordings reveals possible locations of the geographical sources that contributed to secondary tsunami arrivals in southern California. A beamforming technique is applied to the DPG data to determine the azimuths and arrival times of scattered wave energy. In addition, a backward ray tracing procedure is applied to a wide range of back azimuth starting values from the DPG array to map possible source locations. The results show several possible candidates of secondary tsunami source structures. These include the Alaskan Peninsula island chain producing a tsunami arrival ~60 minutes after the first arrival, and the Hawaiian Islands producing an arrival ~170 minutes after the first arrival. The results are mapped into modified tsunami warning messages to show how a time-varying hazard could be communicated with more effective message format and content. The results are demonstrating the effects of including clearly described locations, time of impact, and hazard impact consequences on message perception among the public.

  6. Tsunami Ionospheric warning and Ionospheric seismology

    NASA Astrophysics Data System (ADS)

    Lognonne, Philippe; Rolland, Lucie; Rakoto, Virgile; Coisson, Pierdavide; Occhipinti, Giovanni; Larmat, Carene; Walwer, Damien; Astafyeva, Elvira; Hebert, Helene; Okal, Emile; Makela, Jonathan

    2014-05-01

    studies and improvements, enabling the integration of lateral variations of the solid earth, bathymetry or atmosphere, finite model sources, non-linearity of the waves and better attenuation and coupling processes. All these effects are revealed by phase or amplitude discrepancies in selected observations. We then present goals and first results of source inversions, with a focus on estimations of the sea level uplift location and amplitude, either by using GPS networks close from the epicentre or, for tsunamis, GPS of the Hawaii Islands.

  7. Investigation of late Quaternary fault block uplift along the Motagua/Swan Islands fault system: Implications for seismic/tsunami hazard for the Bay of Honduras

    NASA Astrophysics Data System (ADS)

    Cox, Randel Tom; Lumsden, David N.; Gough, Kevin; Lloyd, Roger; Talnagi, Joseph

    2008-09-01

    Uplifted and warped coastal landforms (fossil coral reef and beachrock, wave-cut and beach terraces) on the western part of Roatan Island off the northern Honduran coast record at least two late Holocene earthquakes that we estimate to have had magnitudes of > M7. Uplift has been primarily related to a fault that follows the southern coast of western Roatan, herein termed the "Flowers Bay fault", a subsidiary fault of the Motagua/Swan Islands Fault System which marks the boundary between the North American and Caribbean plates. Using electron spin resonance (ESR) and radiocarbon ages of calcium carbonate samples and a late Quaternary sea level elevation curve that is compatible with Caribbean sea level data, we constrain the ages and long-term uplift rates of the displaced landforms on Roatan caused by the vertical component of slip on the Flowers Bay fault. The fossil reef that is uplifted along the fault grew between 43 and 34 ka, and the beachrock horizon and lowest uplifted terrace along the southern and western coasts developed between 1000 and 1700 AD. We describe evidence of one earthquake that raised the south coast ~ 3 m (as much as 5 m locally) and that post-dates 1700 AD. We interpret this event to be the great earthquake of August 1856 that generated a tsunami which ran as much as 24 km onto the mainland. Another earthquake circa 900 AD produced a similar amount of uplift as the 1856 event and likely generated a similar tsunami. The age and elevation of the fossil reef suggest a long-term uplift rate of 3 mm/year, consistent with a recurrence interval of ~ 1000 years for these large earthquakes.

  8. Tsunami flooding

    USGS Publications Warehouse

    Geist, Eric; Jones, Henry; McBride, Mark; Fedors, Randy

    2013-01-01

    Panel 5 focused on tsunami flooding with an emphasis on Probabilistic Tsunami Hazard Analysis (PTHA) as derived from its counterpart, Probabilistic Seismic Hazard Analysis (PSHA) that determines seismic ground-motion hazards. The Panel reviewed current practices in PTHA and determined the viability of extending the analysis to extreme design probabilities (i.e., 10-4 to 10-6). In addition to earthquake sources for tsunamis, PTHA for extreme events necessitates the inclusion of tsunamis generated by submarine landslides, and treatment of the large attendant uncertainty in source characterization and recurrence rates. Tsunamis can be caused by local and distant earthquakes, landslides, volcanism, and asteroid/meteorite impacts. Coastal flooding caused by storm surges and seiches is covered in Panel 7. Tsunamis directly tied to earthquakes, the similarities with (and path forward offered by) the PSHA approach for PTHA, and especially submarine landslide tsunamis were a particular focus of Panel 5.

  9. February 27, 2010 Chilean Tsunami in Pacific and its Arrival to North East Asia

    NASA Astrophysics Data System (ADS)

    Zaytsev, Andrey; Pelinovsky, EfiM.; Yalciner, Ahmet C.; Ozer, Ceren; Chernov, Anton; Kostenko, Irina; Shevchenko, Georgy

    2010-05-01

    The outskirts of the fault plane broken by the strong earthquake on February 27, 2010 in Chili with a magnitude 8.8 at the 35km depth of 35.909°S, 72.733°W coordinates generated a moderate size tsunami. The initial amplitude of the tsunami source is not so high because of the major area of the plane was at land. The tsunami waves propagated far distances in South and North directions to East Asia and Wet America coasts. The waves are also recorded by several gauges in Pacific during its propagation and arrival to coastal areas. The recorded and observed amplitudes of tsunami waves are important for the potential effects with the threatening amplitudes. The event also showed that a moderate size tsunami can be effective even if it propagates far distances in any ocean or a marginal sea. The far east coasts of Russia at North East Asia (Sakhalin, Kuriles, Kamchatka) are one of the important source (i.e. November 15, 2006, Kuril Island Tsunami) and target (i.e. February, 27, 2010 Chilean tsunami) areas of the Pacific tsunamis. Many efforts have been spent for establishment of the monitoring system and assessment of tsunamis and development of the mitigation strategies against tsunamis and other hazards in the region. Development of the computer technologies provided the advances in data collection, transfer, and processing. Furthermore it also contributed new developments in computational tools and made the computer modeling to be an efficient tool in tsunami warning systems. In this study the tsunami numerical model NAMI DANCE Nested version is used. NAMI-DANCE solves Nonlinear form of Long Wave (Shallow water) equations (with or without dispersion) using finite difference model in nested grid domains from the source to target areas in multiprocessor hardware environment. It is applied to 2010 Chilean tsunami and its propagation and coastal behavior at far distances near Sakhalin, Kuril and Kamchatka coasts. The main tide gauge records used in this study are from

  10. Exploring tsunamis with non-traditional dataset: array recordings from temporary ocean-bottom seismic experiment

    NASA Astrophysics Data System (ADS)

    Sheehan, A. F.; Yang, Z.; Nicolsky, D.; Mungov, G.; Eakins, B.

    2011-12-01

    We observe clear tsunami signals generated by the July 15, 2009 magnitude 7.8 Dusky Sound (Fiordland) New Zealand earthquake on seafloor differential pressure gauges (DPGs). The dataset was collected during the ocean-bottom seismic experiment, Marine Observations of Anisotropy Near Aotearoa (MOANA). This experiment deployed 30 broadband ocean-bottom seismometers (Trillium 240) and differential pressure gauges (DPGs) for a year (2009/01-2010/02) both in deep ocean (greater than 4000 m water depth) and on the continental shelf (550 m to 1300 m) offshore of the South Island of New Zealand. The DPGs are used in many US National Ocean Bottom Seismograph Instrument Pool (OBSIP) experiments and are designed to record seismic signals. In this study, we demonstrate that DPGs can effectively record open-ocean tsunami signals and the tsunami signals on DPG records can be used for tsunami studies. We carry out waveform and spectral analysis for DPG data recordings of the Fiordland tsunami event. The arrival times of tsunami signals on DPG recordings can be directly used to constrain tsunami wave propagation models. We calibrate the DPGs to obtain better control on the amplitude of the tsunami signals on the DPG records. Calibrations are done over frequency bands of both Rayleigh wave and tidal signals. Synthetic pressure waveforms are calculated to be compared with the DPG recorded signals.

  11. The magnetic fields generated by the tsunami of February 27, 2010

    NASA Astrophysics Data System (ADS)

    Nair, M. C.; Maus, S.; Neetu, S.; Kuvshinov, A. V.; Chulliat, A.

    2010-12-01

    It has long been speculated that tsunamis produce measurable perturbations in the magnetic field. Recent deployments of highly accurate magnetometers and the exceptionally deep solar minimum provided ideal conditions to identify these small signals for the tsunami resulting from the strong Chilean earthquake on February 27, 2010. We find that the magnetic observatory measurements on Easter Island, 3500 km west of the epicenter, show a periodic signal of 1 nT, coincident in time with recordings from the local tide gauge. The amplitude of this signal is consistent with the sea level variation caused by the tsunami in the open ocean near Easter Island through a scaling method proposed by Tyler (2005). In order to have a better understanding of this process, we predict the magnetic fields induced by the Chile tsunami using a barotropic-shallow-water model along with a three-dimensional electromagnetic induction code (Kuvshinov et al., 2002). Initial results indicate good agreement between the predicted and observed magnetic signals at Easter Island. The detection of these magnetic signals represents a milestone in understanding tsunami-induced electromagnetic effects. However, magnetospheric disturbances could limit the practical utility of tsunami electromagnetic monitoring to periods of low solar activity.

  12. Effects of Atmospheric Variability on Ionospheric Manifestations of Earthquakes and Tsunamis

    NASA Astrophysics Data System (ADS)

    Godin, O. A.; Zabotin, N. A.; Zabotina, L.

    2014-12-01

    There is a large and increasing number of ground-based and satellite-borne instruments, which reliably reveal ionospheric manifestations of natural hazards such as large earthquakes, strong tsunamis, and powerful tornadoes. As the focus shifts from detecting the ionospheric features associated with the natural hazards to characterizing the hazards for the purposes of improving early warning systems and contributing to disaster recovery, it becomes imperative to relate quantitatively characteristics of the observed ionospheric disturbances and the underlying natural hazard. The relation between perturbations at the ground level and their ionospheric manifestations is strongly affected by parameters of the intervening atmosphere. In this paper, we employ the ray theory to model propagation of acoustic gravity waves in three-dimensionally inhomogeneous atmosphere. Huygens' wavefront-tracing and Hamiltonian ray-tracing algorithms are used to simulate wave propagation from an earthquake hypocenter through the earth's crust and ocean to the upper atmosphere as well as the generation of atmospheric waves by seismic surface waves and tsunamis. We quantify the influence of temperature stratification and winds, including their seasonal variability, and air viscosity and thermal conductivity on the geometry and amplitude of ionospheric disturbances. Modeling results are verified by comparing observations of the velocity fluctuations at altitudes of 150-160 km by a coastal Dynasonde HF radar system with theoretical predictions of ionospheric manifestations of background infragravity waves in the ocean. Dynasonde radar systems are shown to be a promising means for monitoring acoustic-gravity wave activity and observing ionospheric perturbations due to earthquakes and tsunamis. The effects will be discussed of background ionospheric disturbances and uncertainty in atmospheric parameters on the feasibility and accuracy of retrieval of open-ocean tsunami heights from observations

  13. Tsunami Catalog in Korea

    NASA Astrophysics Data System (ADS)

    Jin, Sobeom; Hyun, Seung Gyu; Noh, Myunghyun

    2015-04-01

    Significant tsunamis are described in historic and instrumental earthquake sources for all regions around the Korean Peninsula. According to the low seismicity near the Peninsula, there are relatively few tsunami events in Korea. Most of the tsunami events are associated with big earthquakes at the eastern margin of the East Sea. One historical event is associated with a volcanic eruption. For that reason, the eastern coast of the Korean Peninsula is the affectable area for tsunami. One historical event at the Yellow Sea area is inferred a result from a big earthquake in China. And one plate boundary earthquake between the Philippine Plate and the Eurasian Plate affected to an island located in south of the Korean Peninsula. We confirmed the historic tsunami events by review the foreign literatures. More detailed information is presented for the instrumental earthquake source events. This work was supported by the Nuclear Safety Research Program through the Korea Radiation Safety Foundation (KORSAFe) and the Nuclear Safety and Security Commission (NSSC), Republic of Korea (Grant No. 1305001).

  14. Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific

    NASA Astrophysics Data System (ADS)

    Lamarche, G.; Popinet, S.; Pelletier, B.; Mountjoy, J.; Goff, J.; Delaux, S.; Bind, J.

    2015-08-01

    We investigated the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using the Gerris flow solver to produce numerical models of tsunami generation, propagation and inundation. Wallis consists of the inhabited volcanic island of Uvéa that is surrounded by a lagoon delimited by a barrier reef. Futuna and the island of Alofi form the Horn Archipelago located ca. 240 km east of Wallis. They are surrounded by a narrow fringing reef. Futuna and Alofi emerge from the North Fiji Transform Fault that marks the seismically active Pacific-Australia plate boundary. We generated 15 tsunami scenarios. For each, we calculated maximum wave elevation (MWE), inundation distance and expected time of arrival (ETA). The tsunami sources were local, regional and distant earthquake faults located along the Pacific Rim. In Wallis, the outer reef may experience 6.8 m-high MWE. Uvéa is protected by the barrier reef and the lagoon, but inundation depths of 2-3 m occur in several coastal areas. In Futuna, flow depths exceeding 2 m are modelled in several populated areas, and have been confirmed by a post-September 2009 South Pacific tsunami survey. The channel between the islands of Futuna and Alofi amplified the 2009 tsunami, which resulted in inundation distance of almost 100 m and MWE of 4.4 m. This first ever tsunami hazard modelling study of Wallis and Futuna compares well with palaeotsunamis recognised on both islands and observation of the impact of the 2009 South Pacific tsunami. The study provides evidence for the mitigating effect of barrier and fringing reefs from tsunamis.

  15. Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific

    NASA Astrophysics Data System (ADS)

    Lamarche, G.; Popinet, S.; Pelletier, B.; Mountjoy, J.; Goff, J.; Delaux, S.; Bind, J.

    2015-04-01

    We investigated the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using the Gerris flow solver to produce numerical models of tsunami generation, propagation and inundation. Wallis consists of the inhabited volcanic island of Uvéa that is surrounded by a lagoon delimited by a barrier reef. Futuna and the island of Alofi forms the Horn Archipelago located ca. 240 km east of Wallis. They are surrounded by a narrow fringing reef. Futuna and Alofi emerge from the North Fiji Transform Fault that marks the seismically active Pacific-Australia plate boundary. We generated fifteen tsunami scenarios. For each, we calculated maximum wave elevation (MWE), inundation distance, and Expected Time of Arrival (ETA). The tsunami sources were local, regional and distant earthquake faults located along the Pacific Rim. In Wallis, the outer reef may experience 6.8 m-high MWE. Uvéa is protected by the barrier reef and the lagoon, but inundation depths of 2-3 m occur in several coastal areas. In Futuna, flow depths exceeding 2 m are modelled in several populated areas, and have been confirmed by a post-September 2009 South Pacific tsunami survey. The channel between the islands of Futuna and Alofi amplified the 2009 tsunami, which resulted in inundation distance of almost 100 m and MWE of 4.4 m. This first-ever tsunami hazard modelling study of Wallis and Futuna compares well with palaeotsunamis recognised on both islands and observation of the impact of the 2009 South Pacific tsunami. The study provides evidence for the mitigating effect of barrier and fringing reefs from tsunamis.

  16. The Chilean tsunami of 16 September 2015: operational aspects and tsunami warning process in French Polynesia.

    NASA Astrophysics Data System (ADS)

    Reymond, Dominique; Jamelot, Anthony

    2016-04-01

    The earthquake of magnitude Mw= 8.3 of 16 September 2015 generated a moderate tsunami in far field that concerned the French Polynesia, with measured tsunami amplitudes until 2.90 m peak-to-through in Marquesas island. We will describe the tsunami warning process that was triggered by this event: the seismic source estimation using two independent methods, and the numerical modeling of the tsunami that was run in real time, the timing of the different processes and actions that were taken in cooperation with Civil Defense. We will present also the comparison between numerical modeling and observed records of the tsunami.

  17. Inland fields of dispersed cobbles and boulders as evidence for a tsunami on Anegada, British Virgin Islands

    USGS Publications Warehouse

    Jaffe, Bruce E.; Watt, Steve; Buckley, Mark

    2012-01-01

    Marine overwash from the north a few centuries ago transported hundreds of angular cobbles and boulders tens to hundreds of meters southward from limestone outcrops in the interior of Anegada, 140 km east–northeast of Puerto Rico. We examined two of several cobble and boulder fields as part of an effort to interpret whether the overwash resulted from a tsunami or a storm in a location where both events are known to occur. One of the cobble and boulder field extends 200 m southward from limestone outcrops that are 300 m inland from the island’s north shore. The other field extends 100 m southward from a limestone knoll located 800 m from the nearest shore. In the two fields, we measured the size, orientation, and spatial distribution of a total of 161 clasts and determined their stratigraphic positions with respect to an overwash sand and shell sheet deposit. In both fields, we found the spacing between clasts increased southward and that clast long-axis orientations are consistent with a transport trending north–south. Almost half the clasts are partially buried in a landward thinning and fining overwash sand and none were found embedded in the shelly mud of a pre-overwash marine pond. The two cobble and boulder fields resemble modern tsunami deposits in which dispersed clasts extend inland as a single layer. The fields contrast with coarse clast storm deposits that often form wedge-shaped shore-parallel ridges. These comparisons suggest that the overwash resulted from a tsunami and not from a storm.

  18. Catastrophic geomorphic effects of the 11 March 2011 Tohoku-Oki Tsunami, Sanriku coastline, northeastern Honshu, Japan

    NASA Astrophysics Data System (ADS)

    Baker, V. R.; Goto, K.; Komatsu, G.; Matsui, T.; Mcguire, L.; Oguchi, T.; Pelletier, J. D.

    2011-12-01

    The Sanriku coastline of northeastern Honshu, Japan, consists of multiple embayments, or inlets into the Kitakami Mountains. This produces a "ria" (drowned river valley) configuration that is particularly susceptible to the enhancement of erosion effects from tsunamis generated at the very active Pacific-Asiatic plate-boundary subduction zone lying approximately 200 km to the east. A preliminary post-Tohoku tsunami survey of areas with minimal artificial construction of sea walls and other coastal defense works revealed that the highest intensity erosion of channels and hill slopes occurred in the narrowest coastal embayments, particularly those with funnel-shaped inlets that open most directly to incident tsunami wave crests. At Aneyoshi, Miyako-Shi, where wave run-up heights achieved 40.5 meters (the highest recorded for the March 11 event), there was spectacular erosion of valley sides, transport and deposition of coarse gravel, and scour-hole generation around large boulders. As at Tokura, just south of Shizugawa (Minamisanriku), regolith and vegetation, including trees, were stripped off hillsides, exposing and scouring bare rock. Inundation levels at these sites show an approximate correspondence to levels reached by the 1896 Meiji-Sanriku tsunami event. Combining this observation with local evidence of older tsunami events, e.g., the 1611 Keicho-Sanriku tsunami and the 869 Jogan tsunami, leads to the suggestion that century-scale repetition of very high-energy tsunami events constitutes a critical factor in long-term coastal erosion for northeastern Honshu, Japan. These preliminary observations are consistent with a threshold phenomenon, whereby the energy expenditures by the incidence tsunami waves must be high enough to exceed resistance factors imposed by vegetation-stabilized regolith on hillsides. When the threshold is exceeded, on the approximate order of once per century, catastrophic erosion and deposition are generated in the local zone of tsunami

  19. Nauru Island Effect Detection Data Set

    DOE Data Explorer

    Long, Chuck

    2010-07-15

    During Nauru99 it was noted that the island was producing small clouds that advected over the ARM site. The Nauru Island Effect Study was run for 1.5 years and the methodology developed to detect the occurrence. Nauru ACRF downwelling SW, wind direction, and air temperature data are used, along with downwelling SW data from Licor radiometers located on the southern end of the island near the airport landing strip. A statistical analysis and comparison of data from the two locations is used to detect the likely occurrence of an island influence on the Nauru ACRF site data

  20. Spectral analysis of Chilean tsunami (February 27, 2010) records on the Pacific coast of Russia

    NASA Astrophysics Data System (ADS)

    Ivelskaya, Tatiana; Shevchenko, George; Korolyov, Pavel

    2010-05-01

    event, we identified as "normal" and selected for analysis of the background signal; the period from 00:00 of February 28 to 24:00 of March 1h ("tsunami period") was chosen for analysis of tsunami-caused oscillations. Two well-expressed peaks with periods about 60 and 45 min were found in the spectra of tsunami records obtained at the Severo-Kurilsk and Vodopadnaya stations. One well-expressed peak with period about 45 min was found in the spectra of tsunami-caused oscillations in the Nikolskoe and Petropavlovsk-Kamchatsky. The same peak in the spectra at different stations (Hanasaki, Korsakov and so on also) is probably connected with tsunami source features. The peak with period 60 min is probably connected with shelf resonant effect in the area adjacent to Paramushir Island and southeastern coast of Kamchatka peninsula. There are some peaks in the high frequency band in the spectra of different stations. These peaks are induced by the local topography resonant effects probably. Low-frequency oscillations with period about 4.8 hours we found in the tsunami records at Korsakov and Petropavlovsk-Kamchatsky. These oscillations are connected with resonant modes of large-size Aniva Bay and Avachinskaya Guba Bay. The same oscillations in these bays were caused by Great Chilian tsunami (May, 1960) too. Similar spectra of both Chilean tsunamis were obtained at Hanasaki and some other stations.

  1. Preliminary assessment of the impacts and effects of the South Pacific tsunami of September 2009 in Samoa

    NASA Astrophysics Data System (ADS)

    Dominey-Howes, D.

    2009-12-01

    The September 2009 tsunami was a regional South Pacific event of enormous significance. Our UNESCO-IOC ITST Samoa survey used a simplified version of a ‘coupled human-environment systems framework’ (Turner et al., 2003) to investigate the impacts and effects of the tsunami in Samoa. Further, the framework allowed us to identify those factors that affected the vulnerability and resilience of the human-environment system before, during and after the tsunami - a global first. Key findings (unprocessed) include: Maximum run-up exceeded 14 metres above sea level Maximum inundation (at right angles to the shore) was approximately 400 metres Maximum inundation with the wave running parallel with the shore (but inland), exceeded 700 metres Buildings sustained varying degrees of damage Damage was correlated with depth of tsunami flow, velocity, condition of foundations, quality of building materials used, quality of workmanship, adherence to the building code and so on Buildings raised even one metre above the surrounding land surface suffered much less damage Plants, trees and mangroves reduced flow velocity and flow depth - leading to greater chances of human survival and lower levels of building damage The tsunami has left a clear and distinguishable geological record in terms of sediments deposited in the coastal landscape The clear sediment layer associated with this tsunami suggests that older (and prehistoric) tsunamis can be identified, helping to answer questions about frequency and magnitude of tsunamis The tsunami caused widespread erosion of the coastal and beach zones but this damage will repair itself naturally and quickly The tsunami has had clear impacts on ecosystems and these are highly variable Ecosystems will repair themselves naturally and are unlikely to preserve long-term impacts It is clear that some plant (tree) species are highly resilient and provided immediate places for safety during the tsunami and resources post-tsunami People of Samoa are

  2. Inversion of tsunami waveforms and tsunami warning

    NASA Astrophysics Data System (ADS)

    An, Chao

    , so we infer that the maximum size of the subfault can be 1/4 to 1/3 of the scale of the faulting area. In Chapter 2, we also developed a method using the inverse residual to evaluate the effectiveness of tsunami buoys of different number and locations in the inversion. Results show that 2 ˜ 4 tsunami buoys are sufficient to constrain the source parameters quite well if they are optimally located. Adding data from more tsunami buoys into the inversion does not significantly improve the results. In addition, near-field stations in the source region do not have advantage against far-field stations in constraining the earthquake source parameters. Conversely, if the near-field data have short but large-amplitude waves and only such data are used in the inversion, it can result in very large but unreal slip near the seabed. The optimal locations for tsunami buoys of different number can also be obtained from this method. Inversions of tele-seismic data show that the inverse results do not necessarily predict the tsunami waves, unless iterative forward modeling techniques are applied to adjust the inverse parameters. Thus, from the standpoint of tsunami warning, tele-seismic data are not able to precisely predict the tsunami wave height or an accurate inundation map, although the estimation of earthquake magnitude and depth might be enough to issue a crude warning. In addition, numerical experiments are conducted and measurements of the computational time show that the calculation of tsunami Green's functions for an area of ˜ 30° only takes several minutes using 256 computational cores. Thus, it is possible to calculate the Green's functions in real time for a tsunami warning system. Finally, a case study is conducted for the South China Sea using the method of inverse residual, leading to recommendations of number and location of tsunami buoys required for a warning system near the Manila trench.

  3. Tide Gauge Observations of 2004-2007 Indian Ocean Tsunamis from Sri Lanka and Western Australia

    NASA Astrophysics Data System (ADS)

    Pattiaratchi, Charitha B.; Sarath Wijeratne, E. M.

    2009-02-01

    Tide gauge data collected from Sri Lanka (three stations) and Western Australia (eleven stations) during the Indian Ocean tsunamis, which occurred in December 2004, March 2005, July 2006, and September 2007, and incorporated five tsunamis, were examined to determine tsunami behaviour during these events. During the December 2004 tsunami, maximum wave heights of 3.87 m and 1.75 m were recorded at Colombo (Sri Lanka) and Bunbury (Western Australia), respectively. The results indicated that although the relative magnitudes of the tsunamis varied, the tsunami behaviour at each station was similar. This was due to the effect of the local and regional topography. At all tide gauges, the spectral energy corresponding to periods between 20 and 85 minutes increased during the tsunami. The sea-level data obtained from the west and south coasts of Sri Lanka (Colombo and Kirinda) indicated the importance of wave reflections from the Maldives Island chain, which produced the maximum wave two to three hours after the arrival of the first wave. In contrast, Trincomalee on the east coast did not show evidence of a reflected wave. Similarly, along the west coast of Australia, the highest waves occurred 15 hours after the arrival of the first wave. Here, based on travel times, we postulated that the waves were reflected from the Mascarene Ridge and/or the Island of Madagascar. Reflected waves were not present in the 2006 tsunami, where the primary waves propagated away from topographic features. One of the main influences of the tsunami was to set up oscillations at the local resonance frequency. Because Sri Lanka and Western Australia have relatively straight coastlines, these oscillations were related to the fundamental period of the shelf oscillation. For Colombo, this corresponded to 75-minute period, whereas in Geraldton and Busselton (Australia), the four-hour period was most prominent; at Jurien Bay and Fremantle, the resonance period was 2.7 hours.

  4. North East Atlantic Tsunamis: Update of the Portuguese Catalogue of Tsunamis

    NASA Astrophysics Data System (ADS)

    Baptista, M. A.; Miranda, J. M.

    2008-12-01

    Catastrophic tsunamis are described in historical sources for all regions around the Gulf of Cadiz, at least since 60 BC. Most of the known events are associated with moderate to large earthquakes and among them the better studied is the 1st November 1755. We present here a review of the events which effects, on the coasts of the Portuguese mainland and Madeira Island, which are well described in historical documents or have been measured by tide gauges since the installation of these instruments. For a few we include new relevant information for the assessment of the tsunami generation or effects, and we discard events that are included in existing compilations but are not supported by quality historical sources or instrumental records. We quote the most relevant quantitative descriptions of tsunami effects on the Portuguese coast, including in all pertinent cases a critical review of the coeval sources, to establish a homogenous event list. When available, instrumental information is presented. We complement all this information with a summary of the conclusions established by paleo-tsunami research.This research was funded by NEAREST and TRANSFER, 6FP EU Projects

  5. Tsunami Impacts in River Environments

    NASA Astrophysics Data System (ADS)

    Tolkova, E.; Tanaka, H.; Roh, M.

    2014-12-01

    The 2010 Chilean and the 2011 Tohoku tsunami events demonstrated the tsunami's ability to penetrate much farther along rivers than the ground inundation. At the same time, while tsunami impacts to the coastal areas have been subject to countless studies, little is known about tsunami propagation in rivers. Here we examine the field data and conduct numerical simulations to gain better understanding of the tsunami impacts in rivers.The evidence which motivated our study is comprised of water level measurements of the aforementioned tsunamis in multiple rivers in Japan, and the 2011 Tohoku and some other tsunamis in the Columbia River in the US. When the available tsunami observations in these very different rivers are brought together, they display remarkably similar patterns not observed on the open coast. Two phenomena were discovered in the field data. First, the phase of the river tide determines the tsunami penetration distance in a very specific way common to all rivers. Tsunami wave progressively disappears on receding tide, whereas high tide greatly facilitates the tsunami intrusion, as seen in the Figure. Second, a strong near-field tsunami causes substantial and prolonged water accumulation in lower river reaches. As the 2011 tsunami intruded rivers in Japan, the water level along rivers rose 1-2 m and stayed high for many hours, with the maximum rise occurring several km from the river mouth. The rise in the water level at some upstream gaging stations even exceeded the tsunami amplitude there.Using the numerical experiments, we attempt to identify the physics behind these effects. We will demonstrate that the nonlinear interactions among the flow components (tsunami, tide, and riverine flow) are an essential condition governing wave dynamics in tidal rivers. Understanding these interactions might explain some previous surprising observations of waves in river environments. Figure: Measurements of the 2010/02/27 tsunami along Naruse and Yoshida rivers

  6. Tsunamis in the Caribbean

    NASA Astrophysics Data System (ADS)

    Farwell, J.; Kelly, A.; Mooney, W. D.

    2006-12-01

    The December 2004 Indian Ocean tsunami increased global awareness to the destruction hazard posed by earthquakes and tsunamis around the world. The United States government has committed 37.5 million dollars toward the upgrade of earthquake and tsunami monitoring systems in the Caribbean region. Several historical earthquakes have caused considerable damage throughout the Caribbean, many causing tsunamis. The US Geological Survey is using a large part of this money to enhance capabilities for rapid detection and notification of earthquakes in the Caribbean in an attempt to warn the millions living in this area of possible tsunamis. The USGS is working with the Puerto Rico Seismic Network, the Seismological Research Unit at the University of West Indies, eight other host countries, and the National Oceanic and Atmospheric Administration (NOAA). These groups are in the process of installing or upgrading seismic monitoring sites in the earthquake zones of the region. NOAA is also installing four Deep-ocean Assessment and Reporting of Tsunami (DART) buoys in support of a Caribbean-wide tsunami warning system. Planned seismic stations are located in Antigua/Barbuda, Barbados, Cuba (U.S. Naval Base at Guantanamo Bay), the Dominican Republic, Jamaica, Honduras, Panama, Turks and Caicos, and Grenada. Satellite telemetry will transmit data from these sites to NEIC, Golden, CO, where the data will be redistributed to NOAA, the University of Puerto Rico and the University of the West Indies, the IRIS Data Management Center and other agencies. The development of seismic monitoring operations began on January 9, 2006. This will improve seismic monitoring capabilities in the Caribbean and Central America, provide better real time data for global monitoring research and assessment activities, and improve understanding of historical tsunamis and their effects on the Caribbean.

  7. Tsunami: ocean dynamo generator.

    PubMed

    Sugioka, Hiroko; Hamano, Yozo; Baba, Kiyoshi; Kasaya, Takafumi; Tada, Noriko; Suetsugu, Daisuke

    2014-01-08

    Secondary magnetic fields are induced by the flow of electrically conducting seawater through the Earth's primary magnetic field ('ocean dynamo effect'), and hence it has long been speculated that tsunami flows should produce measurable magnetic field perturbations, although the signal-to-noise ratio would be small because of the influence of the solar magnetic fields. Here, we report on the detection of deep-seafloor electromagnetic perturbations of 10-micron-order induced by a tsunami, which propagated through a seafloor electromagnetometer array network. The observed data extracted tsunami characteristics, including the direction and velocity of propagation as well as sea-level change, first to verify the induction theory. Presently, offshore observation systems for the early forecasting of tsunami are based on the sea-level measurement by seafloor pressure gauges. In terms of tsunami forecasting accuracy, the integration of vectored electromagnetic measurements into existing scalar observation systems would represent a substantial improvement in the performance of tsunami early-warning systems.

  8. 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.

  9. An Educational Tool for a New Generation of Tsunami Scientists

    NASA Astrophysics Data System (ADS)

    Bernard, E. N.; Robinson, A. R.

    2008-12-01

    What emerges from the 2004 Indian Ocean tsunami and society's response is a call for research that will mitigate the effects of the next tsunami on society. The scale of the 2004 tsunami's impact (227,000 deaths, 10B damage), and the world's compassionate response (13.5B), requires that tsunami research focus on applications that benefit society. Tsunami science will be expected to develop standards that ensure mitigation products are based on state-of-the-science. Standards based on scientifically endorsed procedures assure the highest quality application of this science. Community educational activities will be expected to focus on preparing society for the next tsunami. An excellent starting point for the challenges ahead is education, at all levels, including practitioners, the public, and a new generation of tsunami scientists. To educate the new generation of scientists, Volume 15 of The Sea: Tsunamis has been written to capture the technical elements of tsunami state-of-the-science today. The volume includes: the recorded and geologic history of tsunamis and how to assess the probability of the tsunami risk; the generation of tsunamis; the measurement and modeling of tsunami propagation and inundation; the impacts of tsunamis on coastlines; and tsunami forecast and warnings. Together, this volume gives a technical foundation to apply tsunami science to community-based tsunami preparedness. The editors of The Sea: Tsunamis will present an overview of the volume with emphasis on its value to higher education.

  10. Tsunami hazard map in eastern Bali

    SciTech Connect

    Afif, Haunan; Cipta, Athanasius

    2015-04-24

    Bali is a popular tourist destination both for Indonesian and foreign visitors. However, Bali is located close to the collision zone between the Indo-Australian Plate and Eurasian Plate in the south and back-arc thrust off the northern coast of Bali resulted Bali prone to earthquake and tsunami. Tsunami hazard map is needed for better understanding of hazard level in a particular area and tsunami modeling is one of the most reliable techniques to produce hazard map. Tsunami modeling conducted using TUNAMI N2 and set for two tsunami sources scenarios which are subduction zone in the south of Bali and back thrust in the north of Bali. Tsunami hazard zone is divided into 3 zones, the first is a high hazard zones with inundation height of more than 3m. The second is a moderate hazard zone with inundation height 1 to 3m and the third is a low tsunami hazard zones with tsunami inundation heights less than 1m. Those 2 scenarios showed southern region has a greater potential of tsunami impact than the northern areas. This is obviously shown in the distribution of the inundated area in the south of Bali including the island of Nusa Penida, Nusa Lembongan and Nusa Ceningan is wider than in the northern coast of Bali although the northern region of the Nusa Penida Island more inundated due to the coastal topography.

  11. Tsunami hazard assessment along the U. S. East Coast

    NASA Astrophysics Data System (ADS)

    Tajalli Bakhsh, T.; Grilli, S. T.; Harris, J. C.; Kirby, J. T.; Shi, F.; Tehranirad, B.

    2012-12-01

    In 2005, the National Tsunami Hazard Mitigation Program (NTHMP) was tasked by Congress to develop tsunami inundation maps for the entire US coastline. This work provides an overview of the modeling work related to the development inundation maps along the US east coast. In this region the paucity of historical tsunami records and lack of paleotsunami observations yields a large uncertainty on the source and magnitude of potential extreme tsunami events, and their related coastal hazard. In the Atlantic Ocean basin significant tsunami hazard may result from far-field earthquakes, such as a repeat of the M8.9 Lisbon 1755 event in the Azores convergence zone, or a hypothetical extreme M9 earthquake in the Puerto Rico Trench (PRT). Additionally, it is believed that a repeat of one of the large historical collapses, identified at the toe of the Cumbre Vieja volcano on La Palma (Canary Islands; i.e., with a maximum volume of 450 km3), could pose a major tsunami hazard to the entire US east coast. Finally, in the near-field, large submarine mass failure (SMF) scars have been mapped by USGS, particularly North of the Carolinas (e.g., Currituck), which are believed to have caused past tsunamis. Large SMFs can be triggered by moderate seismicity (M7 or so), such as can occur on the east coast. In fact, one of the few historical tsunamis that significantly affected this region was caused by the 1929 Grand Bank underwater slide, which was triggered by a M7.2 earthquake. In this work we identify and parameterize all potential tsunami sources affecting the US east coast, and perform simulations of tsunami generation, propagation, and coastal impact in a series of increasingly resolved nested grids. Following this methodology, tsunami inundation maps are currently being developed for a few of the most affected areas. In simulations, we use a robust and well-validated Fully Nonlinear Boussinesq long-wave model (FUNWAVE-TVD), on Cartesian or spherical grids. Coseismic tsunami

  12. Puerto Rico Tsunami Warning and Mitigation Program-LANTEX 09 Survey

    NASA Astrophysics Data System (ADS)

    Diaz, W.; von Hillebrandt-Andrade, C.

    2009-12-01

    Tsunami warning, assessment, education, mitigation and preparedness efforts seek to reduce losses related to tsunamis in Puerto Rico (PR). The PR Seismic Network (PRSN) works with governmental agencies and local communities to implement these tsunami hazard risk reduction programs. The Caribbean has a a history of destructive tsunamis such as Virgin Islands (1867), PR (1918) and Dominican Republic (1946). Tsunamis originating near PR are a near-field hazard for as they can reach coastal areas within minutes of a generating event. Sources for regional and tele tsunamis have been identified. To mitigate these risks to communities, the PR Tsunami Warning and Mitigation Program (PRTWMP) was established in 2000 with funding from FEMA, the University of Puerto Rico (UPR) and the PR State Emergency Management Agency (PRSEMA). With the support of NTHMP and TsunamiReady (TR), PR continues to seek to mitigate possible tsunami damages and increase community resilience by helping communities meet the TR guidelines by providing them inundation maps, helping them develop evacuation maps and emergency plans, assisting them with community outreach efforts and conducting evacuation drills. Currently 6 of 44 tsunami threatened communities in PR have been recognized as TsunamiReady. As part of this process, the PRSN, PRSEMA and various communities participated in the LANTEX 2009 tsunami exercise. This exercise took place on April 2, 2009 and was based on a scenario in which an earthquake northeast of PR generates a major tsunami which impacts PR and the USVI and threatens the states along the continental US eastern coast. The municipality of Mayagüez, a TsunamiReady community since 2006, participated in the exercise by activating its Emergency Operations Center , conducting evacuation drills in schools located within its tsunami exposed area, and activating its warning siren. This presentation highlights findings of UPRM social scientists collaborating with the PRTWMP who conducted

  13. Tsunami Source of the 2010 Mentawai, Indonesia Earthquake Inferred from Tsunami Field Survey and Waveform Modeling

    NASA Astrophysics Data System (ADS)

    Satake, Kenji; Nishimura, Yuichi; Putra, Purna Sulastya; Gusman, Aditya Riadi; Sunendar, Haris; Fujii, Yushiro; Tanioka, Yuichiro; Latief, Hamzah; Yulianto, Eko

    2013-09-01

    The 2010 Mentawai earthquake (magnitude 7.7) generated a destructive tsunami that caused more than 500 casualties in the Mentawai Islands, west of Sumatra, Indonesia. Seismological analyses indicate that this earthquake was an unusual "tsunami earthquake," which produces much larger tsunamis than expected from the seismic magnitude. We carried out a field survey to measure tsunami heights and inundation distances, an inversion of tsunami waveforms to estimate the slip distribution on the fault, and inundation modeling to compare the measured and simulated tsunami heights. The measured tsunami heights at eight locations on the west coasts of North and South Pagai Island ranged from 2.5 to 9.3 m, but were mostly in the 4-7 m range. At three villages, the tsunami inundation extended more than 300 m. Interviews of local residents indicated that the earthquake ground shaking was less intense than during previous large earthquakes and did not cause any damage. Inversion of tsunami waveforms recorded at nine coastal tide gauges, a nearby GPS buoy, and a DART station indicated a large slip (maximum 6.1 m) on a shallower part of the fault near the trench axis, a distribution similar to other tsunami earthquakes. The total seismic moment estimated from tsunami waveform inversion was 1.0 × 1021 Nm, which corresponded to Mw 7.9. Computed coastal tsunami heights from this tsunami source model using linear equations are similar to the measured tsunami heights. The inundation heights computed by using detailed bathymetry and topography data and nonlinear equations including inundation were smaller than the measured ones. This may have been partly due to the limited resolution and accuracy of publically available bathymetry and topography data. One-dimensional run-up computations using our surveyed topography profiles showed that the computed heights were roughly similar to the measured ones.

  14. 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

  15. Advantage of wavelet technique to highlight the observed geomagnetic perturbations linked to the Chilean tsunami (2010)

    NASA Astrophysics Data System (ADS)

    Klausner, V.; Mendes, Odim; Domingues, Margarete O.; Papa, Andres R. R.; Tyler, Robert H.; Frick, Peter; Kherani, Esfhan A.

    2014-04-01

    The vertical component (Z) of the geomagnetic field observed by ground-based observatories of the International Real-Time Magnetic Observatory Network has been used to analyze the induced magnetic fields produced by the movement of a tsunami, electrically conducting sea water through the geomagnetic field. We focus on the survey of minutely sampled geomagnetic variations induced by the tsunami of 27 February 2010 at Easter Island (IPM) and Papeete (PPT) observatories. In order to detect the tsunami disturbances in the geomagnetic data, we used wavelet techniques. We have observed an 85% correlation between the Z component variation and the tide gauge measurements in period range of 10 to 30 min which may be due to two physical mechanisms: gravity waves and the electric currents in the sea. As an auxiliary tool to verify the disturbed magnetic fields, we used the maximum variance analysis (MVA). At PPT, the analyses show local magnetic variations associated with the tsunami arriving in advance of sea surface fluctuations by about 2 h. The first interpretation of the results suggests that wavelet techniques and MVA can be effectively used to characterize the tsunami contributions to the geomagnetic field and further used to calibrate tsunami models and implemented to real-time analysis for forecast tsunami scenarios.

  16. Deep-Ocean Measurements of Tsunami Waves

    NASA Astrophysics Data System (ADS)

    Rabinovich, Alexander B.; Eblé, Marie C.

    2015-12-01

    Deep-ocean tsunami measurements play a major role in understanding the physics of tsunami wave generation and propagation, and in improving the effectiveness of tsunami warning systems. This paper provides an overview of the history of tsunami recording in the open ocean from the earliest days, approximately 50 years ago, to the present day. Modern tsunami monitoring systems such as the self-contained Deep-ocean Assessment and Reporting of Tsunamis and innovative cabled sensing networks, including, but not limited to, the Japanese bottom cable projects and the NEPTUNE-Canada geophysical bottom observatory, are highlighted. The specific peculiarities of seafloor longwave observations in the deep ocean are discussed and compared with observations recorded in coastal regions. Tsunami detection in bottom pressure observations is exemplified through analysis of distant (22,000 km from the source) records of the 2004 Sumatra tsunami in the northeastern Pacific.

  17. Tsunami hazard assessment in the Colombian Caribbean Coast with a deterministic approach

    NASA Astrophysics Data System (ADS)

    Otero Diaz, L.; Correa, R.; Ortiz R, J. C.; Restrepo L, J. C.

    2014-12-01

    For the Caribbean Sea, we propose six potential tectonic sources of tsunami, defining for each source the worst credible earthquake from the analysis of historical seismicity, tectonics, pasts tsunami, and review of IRIS, PDE, NOAA, and CMT catalogs. The generation and propagation of tsunami waves in the selected sources were simulated with COMCOT 1.7, which is a numerical model that solves the linear and nonlinear long wave equations in finite differences in both Cartesian, and spherical coordinates. The results of the modeling are presented in maps of maximum displacement of the free surface for the Colombian Caribbean coast and the island areas, and they show that the event would produce greater impact is generated in the source of North Panama Deformed Belt (NPDB), where the first wave train reaches the central Colombian coast in 40 minutes, generating wave heights up to 3.7 m. In San Andrés and Providencia island, tsunami waves reach more than 4.5 m due effects of edge waves caused by interactions between waves and a barrier coral reef around of each island. The results obtained in this work are useful for planning systems and future regional and local warning systems and to identify priority areas to conduct detailed research to the tsunami threat.

  18. Preliminary numerical simulations of the 27 February 2010 Chile tsunami: first results and hints in a tsunami early warning perspective

    NASA Astrophysics Data System (ADS)

    Tinti, S.; Tonini, R.; Armigliato, A.; Zaniboni, F.; Pagnoni, G.; Gallazzi, Sara; Bressan, Lidia

    2010-05-01

    The tsunamigenic earthquake (M 8.8) that occurred offshore central Chile on 27 February 2010 can be classified as a typical subduction-zone earthquake. The effects of the ensuing tsunami have been devastating along the Chile coasts, and especially between the cities of Valparaiso and Talcahuano, and in the Juan Fernandez islands. The tsunami propagated across the entire Pacific Ocean, hitting with variable intensity almost all the coasts facing the basin. While the far-field propagation was quite well tracked almost in real-time by the warning centres and reasonably well reproduced by the forecast models, the toll of lives and the severity of the damage caused by the tsunami in the near-field occurred with no local alert nor warning and sadly confirms that the protection of the communities placed close to the tsunami sources is still an unresolved problem in the tsunami early warning field. The purpose of this study is two-fold. On one side we perform numerical simulations of the tsunami starting from different earthquake models which we built on the basis of the preliminary seismic parameters (location, magnitude and focal mechanism) made available by the seismological agencies immediately after the event, or retrieved from more detailed and refined studies published online in the following days and weeks. The comparison with the available records of both offshore DART buoys and coastal tide-gauges is used to put some preliminary constraints on the best-fitting fault model. The numerical simulations are performed by means of the finite-difference code UBO-TSUFD, developed and maintained by the Tsunami Research Team of the University of Bologna, Italy, which can solve both the linear and non-linear versions of the shallow-water equations on nested grids. The second purpose of this study is to use the conclusions drawn in the previous part in a tsunami early warning perspective. In the framework of the EU-funded project DEWS (Distant Early Warning System), we will

  19. Interdisciplinary approaches to better understand the past tsunamis -Case study of the 1771 Meiwa Tsunami, Japan-

    NASA Astrophysics Data System (ADS)

    Goto, K.

    2012-12-01

    It is important to know frequency and magnitude of past tsunamis over hundred to thousand years to better understand the risk from low-frequency large tsunamis. Historical documents, archeological evidence, and sediments laid down by tsunamis in coastal environments are useful for understanding the past tsunamis. Among them, tsunami geology has become a subject of great interest since the March 11, 2011 Tohoku-oki tsunami, Japan. This is because the 2011 tsunami was suspected as a recurrence of the AD869 Jogan tsunami, which was well known based on the geological and historical evidence. Our newly acquired geological data on the 2011 tsunami however, suggest that previous estimates of the Jogan tsunami have probably been underestimated [Goto et al., 2011]. This suggests that more interdisciplinary research is needed to better understand the historical and prehistoric tsunamis. As an example of the interdisciplinary research to better understand the past tsunami, here I review the studies of the AD1771 Meiwa Tsunami and its predecessors that struck the southern Ryukyu Islands, Japan. Reliable historical documents suggest run-up heights of up to 30 m for this tsunami [e.g. Goto et al., 2010], which are well supported by the archeological evidence as well as local traditions. Moreover, the displacement of specific coral boulders by the tsunami is also described in detail. Geological studies and numerical modeling of the boulder transport by the tsunami further revealed that many coral boulders of several hundred tons were deposited by the tsunami [e.g. Goto et al., 2010]. Based on such researches, the source model for the tsunami was estimated by the high-resolution numerical modeling, although it remains still controversial. Our study suggests that all available historical, geological, and archaeological data should be collected to better estimate the historical and prehistoric tsunami source model. The field evidences are still increasing for the 1771 Meiwa Tsunami

  20. 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

  1. Tsunami Research and Monitoring Enabled through Ocean Network Canada's NEPTUNE Cabled Observatory

    NASA Astrophysics Data System (ADS)

    Heesemann, M.; Insua, T. L.; Mihaly, S. F.; Thomson, R.; Rabinovich, A.; Fine, I.; Scherwath, M.; Moran, K.

    2014-12-01

    Ocean Networks Canada (ONC; http://www.oceannetworks.ca/) operates the multidisciplinary NEPTUNE and VENUS cabled ocean observatories off the west coast of Canada and an increasing number of miniature ocean observatories, such as in the Canadian Arctic. All data collected by these observatories are archived and publicly available through ONC's Oceans 2.0 data portal. Much of the data are related to marine geohazards, such as earthquakes, submarine landslides, and tsunamis and are delivered in real-time to various agencies, including early warning centers. The NEPTUNE and VENUS cabled observatories consist of over 850 km of cable deployed inshore and offshore off Vancouver Island and covers the coastal zones, the northern part of the Cascadia subduction zone, Cascadia Basin, and the Endeavour Segment of the Juan de Fuca Ridge. Geological evidence suggests that there is a 25-40% probability of a magnitude 8 or greater megathrust earthquake along the Cascadia subduction zone in the next 50 years and that the most recent great earthquake (estimated magnitude ~9.0) that occurred in 1700 caused widespread tsunami damage. However, most of the tsunamis that arrive in the area originate from distant sources around the Pacific. Over the last 100 years, numerous major tsunamis have occurred in the Pacific Ocean, killing many tens of thousands of people. The NEPTUNE observatory includes high-precision bottom pressure recorders (BPRs) at each major nodes and a tsunami meter consisting of three BPRs arranged on a ~20 km radius circle around the flat Cascadia Basin site. On September 30, 2009, just days after the first NEPTUNE instruments were installed, the first tsunami waves of 2.5-6.0 cm amplitude generated by the Mw 8.1 Samoa earthquake were recorded by six BPRs. The Samoan tsunami was followed by several other events recorded by the network, including the 2010 Chilean tsunami, the 2011 Tōhoku-Oki earthquake and tsunami, and the 2012 Haida Gwaii tsunami. These open

  2. 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

  3. Effects of magnetic islands on drift wave instability

    SciTech Connect

    Jiang, P.; Lin, Z. Holod, I.; Xiao, C.

    2014-12-15

    Magnetic islands have been implemented in the gyrokinetic toroidal code to study the effects of the islands on microturbulence. The pressure profile flattening is verified in the simulation with the islands. Simulations of ion temperature gradient instability find that different toroidal modes are linearly coupled together and that toroidal spectra become broader when the island width increases. The real frequencies and growth rates of different toroidal modes approach each other with the averaged value independent of the island width. The linear mode structures are enhanced at the island separatrices and weakened at the island centers, consistent with the flattening of the pressure profile inside the islands.

  4. Observation of the 2009 Samoa tsunami by the NEPTUNE-Canada cabled observatory: Test data for an operational regional tsunami forecast model

    NASA Astrophysics Data System (ADS)

    Thomson, Richard; Fine, Isaac; Rabinovich, Alexander; Mihály, Steve; Davis, Earl; Heesemann, Martin; Krassovski, Maxim

    2011-06-01

    As part of the NEPTUNE-Canada cabled seafloor observatory, an array of six high-precision bottom pressure recorders was installed in the late summer of 2009 at depths from 100 to 2600 m seaward of the southwest coast of Vancouver Island in the northeast Pacific. The instruments transmit 1-sec bottom pressure data at roughly 0.1 mm equivalent sea level height to the Data Management and Archiving System (DMAS) at the University of Victoria. On September 30, 2009, the array recorded waves of 2.5 to 6 cm amplitude associated with the transoceanic tsunami generated by the Mw = 8.1 Samoa earthquake in the South Pacific. These open-ocean observations were uncontaminated by coastal effects, demonstrating that NEPTUNE records from future tsunami events can be effectively used as realtime input to a regional numerical tsunami forecast model. We validate this proposition by showing that wave forms simulated by the regional model using the leading train of waves of the 2009 event are in good agreement with observed tsunami records for both the shelf stations and nearby coastal tide gauges. Tsunami waves simulated by this model are also significantly more accurate for local regions than those determined by global-scale tsunami models. This ability to assimilate “pristine” open-ocean data from the cabled observatory into an operational tsunami forecast model makes it possible to provide updated wave information that could help mitigate the impact of future tsunamis approaching the west coast of British Columbia and northern Washington State.

  5. How study of hurricane swell can help to provide a better prediction of the tsunami wave propagation on Caribbean coasts?

    NASA Astrophysics Data System (ADS)

    Dorville, Jean-François; Dondin, Frédéric; Cécé, Raphael; Bernard, Didier

    2014-05-01

    Prediction of tsunami wave propagation on a complex bathymetry can be fatal. Do a mistake on the location of the tsunami wave impact on the coast is highly dangerous. The destruction due to mechanical impact or submersion of the large area of the coast zone can be avoid with a good estimation (i.e.; height, location, duration) of the hazard. Features of the propagation are important in term of values but also in term of dynamic, an evacuation plan is directly base on the prediction of the sequence of events. The frequency of large tsunami is low, but the study of real case may help to have a complete comprehension of the process. We would be better prepare for a tsunami if we had more tsunami. Caribbean arc was generated by an intense tectonic motion and volcanic activity. The risk of tsunami is high in the area both generated by tectonic motion and volcanic landslide. The quality of a numerical propagation of tsunami is highly dependent of the quality of the DEM Caribbean coast are impact by large Hurricane wave. The study of those can be helpful in the tsunami study, particularly for the bathymetry effect on large wave. The shape of the both types of wave are not the same, we do not try to do a direct comparison, but used the information of the dispersion of large swell wave to applied it to the tsunami dispersion and fill the lack of information of the bathymetry. We focus on the comparative study of the propagation of tsunami wave generated by submarine volcano land slide and hurricane wave on a small scale bathymetry (10 m, Lito 3d). The case of Guadeloupe and Martinique island are detailed in this study, due to the available dataset. We used those two territories as reference area. The numerical propagation of the waves is done with FUNWAVE on two different bathymetry (10 m & 50 m). The tsunami wave was generated by VolcFlow in case of submarine volcano collapse and the swell determine by coupling of WaveWatchIII and SWAN in case of past Hurricane. The

  6. Development of a Tsunami Inundation Map in Detecting Tsunami Risk in Gulf of Fethiye, Turkey

    NASA Astrophysics Data System (ADS)

    Dilmen, Derya Itir; Kemec, Serkan; Yalciner, Ahmet Cevdet; Düzgün, Sebnem; Zaytsev, Andrey

    2015-03-01

    NAMIDANCE tsunami simulation and visualization tool is used to create tsunami inundation maps showing quantitative maximum tsunami flow depths in Fethiye. The risk of an extreme, but likely earthquake-generated tsunami is estimated at Fethiye Bay for 14 probabilistic earthquake scenarios. The bay is located 36°39'5″N 29°7'23″E, southwestern Turkey, which has coastline to the eastern Mediterranean Sea. The tsunami simulation and inundation assessment are performed in three stages: (1) formation of a digital elevation model of the region from the best available topography/bathymetry dataset, (2) estimation of a maximum credible tsunami scenario for the region and determination of related earthquake parameters, (3) high resolution tsunami simulation and computation of near shore and overland tsunami dynamics in the study area using tsunami simulation and visualization code NAMIDANCE, (4) determination of spatial distributions of tsunami characteristics (maximum water elevations, water velocities, flow depths) under the critical tsunami condition. The results are based on the most recent descriptions of potential tsunami sources, topographic and bathymetric databases, and tsunami numerical models. We present an innovative study concentrating on preparation of quantitative flow depths and inundation maps with a very high-resolution bathymetry/topographic dataset in the eastern Mediterranean. Inundation maps will be used to analyze the effects of possible tsunamis. The presented research is crucial to raising the awareness of government officials, the public, and other stake holders about the high probability of a tsunami event in Turkey. Moreover, the results of this study will help to plan for evacuation routes, establish safe zones, and assist in preparation for the tsunami, creating public awareness, and planning evacuation routes before the actual tsunami event happens.

  7. Lessons learnt from the Indian Ocean Tsunami 2004: the role of surface and subsurface topography in deep water tsunami propagation

    NASA Astrophysics Data System (ADS)

    Pattiaratchi, C. B.

    2014-12-01

    The Indian Ocean experienced its most devastating natural disaster through the action of a Tsunami, resulting from of an earthquake off the coast of Sumatra on 26th of December 2004. This resulted in widespread damage both to property and human lives with over 250,000 deaths in the region and many millions homeless. Our understanding of tsunami generation and propagation has increased significantly over the past decade. In this presentation, results obtained from detailed analysis of sea level data from Western Australia and Sri Lanka together with numerical modelling are presented to highlight the effects of topography both at the surface and subsurface. The major effects are due to wave reflection and refraction. Examples of wave reflection include: impacts on Malaysia/Thailand, Sri Lanka and Western Australia due to wave reflection from Sri Lanka, Maldives and Mascarene Ridge, respectively. In the case of Sri Lanka, the maximum wave height recorded along the west coast during the 2004 tsunami was due to the reflected wave from Maldives impacting 3 hours after the arrival of the initial waves. Similarly, along the West coast of Australia highest waves occurred 15 hours after the arrival of the first wave. Here, based on travel times, we postulate that the waves were reflected from the Mascarene Ridge and/or the island of Madagascar (Figure 1b). The conclusions based on observations were verified using numerical model simulations using the MOST and ComMIT models. Numerical modelling using the MOST model indicated the role of offshore susurface topography on tsunami propagation through wave wave refraction. Examples of wave refraction included the effects of deep water seamounts (Venin Meinesz) and plateaus (Wallaby, Cuvier and Exmouth) on tsunami propagation along the West Australian coast. The tsunami waves are first scattered by the Venin Meinesz seamounts and were then refracted by the Wallaby and Cuvier plateaus resulting in waves being deflected onto the

  8. Puerto Rico Tsunami Warning and Mitigation Program

    NASA Astrophysics Data System (ADS)

    Huerfano, V. A.; Mercado, A.; von Hillebrandt, C. G.

    2003-12-01

    The circum-Caribbean region has a documented history of large damaging tsunamis that have affected coastal areas, including the events of the Virgin Islands in 1867 and Mona Passage in 1918. These tsunamis have been triggered by large tsunamigenic earthquakes that deformed the ocean floor. The seismic water waves originating in the prominent fault system 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 regional and tele tsunamis have also been identified. To help mitigate the risk of potential tsunamis on the coastal communities of Puerto Rico, with initial funding from the Federal Emergency Management Administration (FEMA) and the University of Puerto Rico (UPR), the Puerto Rico Tsunami Warning and Mitigation Program (PRTWMP) was established in 2000. Three of the main tasks are to evaluate the possibility of establishing a Tsunami Warning System (TWS), prepare tsunami flood maps and education. The need to establish a system of rapid notification for tsunami alerting in the Caribbean region has been recognized by the emergency management and scientific community. Presently, the Puerto Rico Seismic Network (PRSN) of the University of Puerto Rico at Mayag\\x81ez is establishing a Tsunami Warning System (TWS) for PR/VI. Part of the TWS is the EarlyBird system, developed by the West Coast/Alaska Tsunami Warning Center, which has been running in the PRSN since January, 2003. This program automatically locates and disseminates information on potentially tsunamigenic earthquakes. Also, the existing protocol for exchanging data and information on potentially tsunamigenic events in the PR/VI is currently being reviewed by the concerned institutions. Tsunami flood maps were prepared for all of Puerto Rico, including the island municipalities of Vieques and Culebra. These flood maps were generated in three phases. First, hypothetical

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. Observations of the 2004 and 2006 Indian Ocean tsunamis from a pressure gauge array in Indonesia

    NASA Astrophysics Data System (ADS)

    Drushka, Kyla; Sprintall, Janet; Gille, Sarah T.; Pranowo, Widodo S.

    2008-07-01

    Five shallow pressure gauges located in straits in the southern Indonesian islands were used to evaluate tsunami signals triggered by the earthquakes off the northwest coast of Sumatra in December 2004 and the south coast of Java in July 2006. Tsunami waves reached the pressure gauges around 5 to 6 hours after the 2004 earthquake; the largest waves arrived 10 to 23 hours later, with amplitudes ranging from 9 to 25 cm. After the 2006 earthquake, tsunami arrivals were only evident at the Ashmore and Roti pressure gauges in Timor Passage. At these two gauges, the first waves arrived around 2.25 hours after the earthquake, and the largest waves arrived 2 to 3 hours later, with amplitudes of 6 and 18 cm. Spectral analysis shows an increase of energy in the 40- to 80-min-period band during the 2004 tsunami, and at periods of 10 to 20 min in 2006. A simple ray tracing model of both the 2004 and 2006 events, which approximates the tsunami as a shallow water wave, was used to evaluate the effect of topography on tsunami propagation in order to provide a physical explanation for the features observed in the pressure gauge data.

  14. Japan: Tsunami

    Atmospheric Science Data Center

    2013-04-16

    ... tsunami triggered by the March 11, 2011, magnitude 8.9 earthquake centered off Japan's northeastern coast about 130 kilometers (82 ... inland from the eastern shoreline is visible in the post-earthquake image. The white sand beaches visible in the pre-earthquake view are ...

  15. 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

  16. A probabilistic tsunami hazard assessment for Indonesia

    NASA Astrophysics Data System (ADS)

    Horspool, N.; Pranantyo, I.; Griffin, J.; Latief, H.; Natawidjaja, D. H.; Kongko, W.; Cipta, A.; Bustaman, B.; Anugrah, S. D.; Thio, H. K.

    2014-11-01

    Probabilistic hazard assessments are a fundamental tool for assessing the threats posed by hazards to communities and are important for underpinning evidence-based decision-making regarding risk mitigation activities. Indonesia has been the focus of intense tsunami risk mitigation efforts following the 2004 Indian Ocean tsunami, but this has been largely concentrated on the Sunda Arc with little attention to other tsunami prone areas of the country such as eastern Indonesia. We present the first nationally consistent probabilistic tsunami hazard assessment (PTHA) for Indonesia. This assessment produces time-independent forecasts of tsunami hazards at the coast using data from tsunami generated by local, regional and distant earthquake sources. The methodology is based on the established monte carlo approach to probabilistic seismic hazard assessment (PSHA) and has been adapted to tsunami. We account for sources of epistemic and aleatory uncertainty in the analysis through the use of logic trees and sampling probability density functions. For short return periods (100 years) the highest tsunami hazard is the west coast of Sumatra, south coast of Java and the north coast of Papua. For longer return periods (500-2500 years), the tsunami hazard is highest along the Sunda Arc, reflecting the larger maximum magnitudes. The annual probability of experiencing a tsunami with a height of > 0.5 m at the coast is greater than 10% for Sumatra, Java, the Sunda islands (Bali, Lombok, Flores, Sumba) and north Papua. The annual probability of experiencing a tsunami with a height of > 3.0 m, which would cause significant inundation and fatalities, is 1-10% in Sumatra, Java, Bali, Lombok and north Papua, and 0.1-1% for north Sulawesi, Seram and Flores. The results of this national-scale hazard assessment provide evidence for disaster managers to prioritise regions for risk mitigation activities and/or more detailed hazard or risk assessment.

  17. Hindcast of the 2009 South Pacific tsunami - validation of GIS methodologies for local vulnerability and risk assessment in American Samoa

    NASA Astrophysics Data System (ADS)

    Harbitz, C. B.; Sverdrup-Thygeson, K.; Kaiser, G.; Swarny, R.; Gruenburg, L.; Glimsdal, S.; Løvholt, F.; McAdoo, B. G.; Frauenfelder, R.

    2010-12-01

    On September 29th, 2009 at 6:48 AM local time, a series of earthquakes generated near the Tonga trench (15.509°S, 172.034°W) triggered a tsunami that reached the shores of Tonga, the Independent State of Samoa, and American Samoa. Effects of the tsunami were seen on several other Pacific islands. Devastation was widespread, resulting in 9 fatalities in Tonga, 149 in the independent State of Samoa and 34 in this study’s region of focus, American Samoa, which was selected mainly because of better data availability. Pago Pago, the capital on the main island of Tutuila, was especially affected by the tsunami because of its natural deep water harbor. Leone, located on the southwest coast of the island, was hit directly by waves propagating northeast from the earthquake’s epicenter. The villages of Poloa, Amanave, Alao, and Tula were also heavily damaged, but Leone and Pago Pago sustained some of the most wide-spread damage on Tutuila due to the combination of large populations with environmental and geographic factors. Following the disaster, teams from several nations evaluated damages and evidence of inundation levels. This study seeks to use information (including population, building types, infrastructure, inundation, flow depth, damages, and death tolls) gathered after the tsunami by researchers in American Samoa in order to validate a pre-existing GIS tsunami vulnerability and risk assessment model. The tsunami inundation, damage and mortality information found from journal papers, reports, newspaper articles, internet, personal communication with local agencies, photos, aerial views, and satellite images, was applied to deduce population density, building vulnerability, and the cause and location of tsunami deaths. The GIS model was adapted for optimal use of the available data. In the GIS model the mortality risk is a “product” of hazard, exposure, and mortality. The hazard is represented by the maximum tsunami flow depth, the exposure is described by

  18. The effects of the 2004 tsunami on a coastal aquifer in Sri Lanka.

    PubMed

    Vithanage, Meththika; Engesgaard, Peter; Villholth, Karen G; Jensen, Karsten H

    2012-01-01

    On December 26, 2004, the earthquake off the southern coast of Sumatra in the Indian Ocean generated far-reaching tsunami waves, resulting in severe disruption of the coastal aquifers in many countries of the region. The objective of this study was to examine the impact of the tsunami on groundwater in coastal areas. Field investigations on the east coast of Sri Lanka were carried out along a transect located perpendicular to the coastline on a 2.4 km wide sand stretch bounded by the sea and a lagoon. Measurements of groundwater table elevation and electrical conductivity (EC) of the groundwater were carried out monthly from October 2005 to August 2007. The aquifer system and tsunami saltwater intrusion were modeled using the variable-density flow and solute transport code HST3D to understand the tsunami plume behavior and estimate the aquifer recovery time. EC values reduced as a result of the monsoonal rainfall following the tsunami with a decline in reduction rate during the dry season. The upper part of the saturated zone (down to 2.5 m) returned to freshwater conditions (EC < 1000 µS/cm) 1 to 1.5 years after the tsunami, according to field observations. On the basis of model simulations, it may take more than 15 years for the entire aquifer (down to 28 m) to recover completely, although the top 6 m of the aquifer may become fresh in about 5 years.

  19. The 2004 tsunami in Penang, Malaysia: early mental health intervention.

    PubMed

    Krishnaswamy, Saroja; Subramaniam, Kavitha; Indran, Tishya; Low, Wah-Yun

    2012-07-01

    Disasters, natural or man-made, bring numerous health care challenges. In any crisis, mental health programs are a requirement during both the acute and postemergency phases. In the Asian tsunami on December 26, 2004, some of the northwestern coastal areas of Malaysia, particularly the island of Penang, were affected with devastating effects on the residents. Such disasters can predispose to mental health problems among the affected people. An early mental health intervention program was carried out in Balik Pulau, Penang, an area badly affected by the tsunami. The objective of the intervention program was to identify the victims, counsel them, make referrals if necessary, and provide help and resources to prevent the development of mental health problems. Penang residents identified as tsunami victims by the local health authorities were recruited. A group of health care workers, school teachers, village authorities, and volunteers were trained to carry out the crisis intervention program by health care workers experienced in crisis interventions. A total of 299 adults participated in the crisis intervention program, with follow-up assessments being made 4 to 6 weeks later. At the follow-up assessment, 1% of the victims had a problem and they were then referred for further medical assessment. This indicates that the intervention program in the first 2 weeks after the tsunami disaster with referrals to medical services may have helped stabilize the victims.

  20. Effects of heavy elements in the sludge conveyed by the 2011 tsunami on human health and the recovery of the marine ecosystem

    NASA Astrophysics Data System (ADS)

    Sera, K.; Goto, S.; Takahashi, C.; Saitoh, Y.; Yamauchi, K.

    2014-01-01

    The 2011 tsunami not only caused significant damage, but also drew a large amount of sludge from the bottom of the sea. This may have exerted negative effects on human health. In order to evaluate changes in elemental concentrations in the body before and after the tsunami, we collected long hairs from victims of the disaster. Furthermore, sludge and plant samples were collected from three prefectures. The sludge samples on land were found to be still contaminated with heavy elements. The concentrations of heavy elements in the soils and plants gathered from the same tidelands decreased after one year. In hair analyses, no clear changes have been observed in heavy element concentrations measured before and after the tsunami. However, the concentration of some essential elements, such as Cu, Ca and Mg, showed a decreasing tendency after the tsunami.

  1. 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

  2. Could a 1755-Like Tsunami Reach the French Atlantic Coastline? Constraints from Twentieth Century Observations and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Allgeyer, S.; Daubord, C.; Hébert, H.; Loevenbruck, A.; Schindelé, F.; Madariaga, R.

    2013-09-01

    The tsunami generated by the 1 November, 1755 earthquake off the coast of Portugal affected mainly the coastlines of the Iberian Peninsula and Northwest Morocco, but was also observed in some places along the North Atlantic coasts. To determine whether the event could have effected the French coastline, we conducted a study to search for signs of the tsunami in historical records from all tide gauge stations off the French Atlantic coast during the twentieth century, specifically for the 28 February, 1969 and the 26 May, 1975 tsunamis that were recorded by the Portuguese tide gauge network. Because many recordings are available in La Rochelle (located on the southwest coast of France), we focused our study on this harbor. The analysis of the tide gauge data shows no evidence for tsunamis in La Rochelle, neither in 1969 nor in 1975. To confirm this lack of tsunami signals, we used nonlinear, shallow water equations to compute the tsunami propagation to the French Atlantic coastline for both 1969 and 1975 events. Results obtained from these simulations confirm otherwise unnoticeable wave amplitudes at La Rochelle harbor. In a second step, tsunamis from three different scenarios for the 1755 earthquake were modeled to estimate the impact of such a tsunami on the French Atlantic coast, with a focus on La Rochelle harbor. A comparison of the functions of tide configuration was made in order to analyse the difference in impact. The results show that, while the harbor is poorly impacted, several areas (western part of the island of Ré and northern coast of the island of Oléron) may have experienced a moderate impact from 0.5 to 1 m, especially since the tide was high at the time of arrival, possibly causing local inundations in lowland areas.

  3. Field survey of the 2009 tsunami in American Samoa

    NASA Astrophysics Data System (ADS)

    Koshimura, S.; Nishimura, Y.; Nakamura, Y.; Namegaya, Y.; Fryer, G. J.; Akapo, A.; Kong, L. S.; Vargo, D.

    2009-12-01

    We conducted a post-tsunami field survey of the 2009 tsunami in Tutuila island, American Samoa from 5 to 8 Oct., 2009, focusing on the measurements of tsunami run-up height, flow depth, extent of inundation zone, coastal erosion/sedimentation, structural damage inspection, and collecting eyewitness accounts. In total, we measured tsunami heights at 50 points in the island using the total station, hand-held GPS and survey rods. Throughout the survey, we found that the tsunami devastated the villages along the western coast with the highest run-up of 16.3 m (above the sea level at tsunami arrival) at Poloa where almost all the houses were washed-away or collapsed, and 12.4 m inundation height at Amanave where the tsunami penetrated approximately 200 m inland. Also, severe damage were found at Leone (south western coast ; 6 m as inundation height), Pago Pago harbor (central coast; 5m as inundation height, 2 m as flow depth and approximately 500 m inland tsunami penetration), and Tula (eastern coast ; less than 6m as inundation height). We also surveyed the structural damage in Pago Pago harbor, by the interpretation of high-resolution satellite images (QuickBird) and on-site inspection with GPS measurement, which leads to the understanding of relations between the tsunami hazard and structural vulnerability. Measured tsunami inundation heights after tide correction.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    NASA Astrophysics Data System (ADS)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-12-01

    This work is part of a tsunami inundation mapping activity carried out along the US East Coast since 2010, under the auspice of the National Tsunami Hazard Mitigation program (NTHMP). The US East Coast features two main estuaries with significant tidal forcing, which are bordered by numerous critical facilities (power plants, major harbors,...) as well as densely built low-level areas: Chesapeake Bay and the Hudson River Estuary (HRE). HRE is the object of this work, with specific focus on assessing tsunami hazard in Manhattan, the Hudson and East River areas. In the NTHMP work, inundation maps are computed as envelopes of maximum surface elevation along the coast and inland, by simulating the impact of selected probable maximum tsunamis (PMT) in the Atlantic ocean margin and basin. At present, such simulations assume a static reference level near shore equal to the local mean high water (MHW) level. Here, instead we simulate maximum inundation in the HRE resulting from dynamic interactions between the incident PMTs and a tide, which is calibrated to achieve MHW at its maximum level. To identify conditions leading to maximum tsunami inundation, each PMT is simulated for four different phases of the tide and results are compared to those obtained for a static reference level. We first separately simulate the tide and the three PMTs that were found to be most significant for the HRE. These are caused by: (1) a flank collapse of the Cumbre Vieja Volcano (CVV) in the Canary Islands (with a 80 km3 volume representing the most likely extreme scenario); (2) an M9 coseismic source in the Puerto Rico Trench (PRT); and (3) a large submarine mass failure (SMF) in the Hudson River canyon of parameters similar to the 165 km3 historical Currituck slide, which is used as a local proxy for the maximum possible SMF. Simulations are performed with the nonlinear and dispersive long wave model FUNWAVE-TVD, in a series of nested grids of increasing resolution towards the coast, by one

  9. The Transoceanic 1755 Lisbon Tsunami in Martinique

    NASA Astrophysics Data System (ADS)

    Roger, J.; Baptista, M. A.; Sahal, A.; Accary, F.; Allgeyer, S.; Hébert, H.

    2011-06-01

    On 1 November 1755, a major earthquake of estimated M w=8.5/9.0 destroyed Lisbon (Portugal) and was felt in the whole of western Europe. It generated a huge transoceanic tsunami that ravaged the coasts of Morocco, Portugal and Spain. Local extreme run-up heights were reported in some places such as Cape St Vincent (Portugal). Great waves were reported in the Madeira Islands, the Azores and as far as the Antilles (Caribbean Islands). An accurate search for historical data allowed us to find new (unpublished) information concerning the tsunami arrival and its consequences in several islands of the Lesser Antilles Arc. In some places, especially Martinique and the Guadeloupe islands, 3 m wave heights, inundation of low lands, and destruction of buildings and boats were reported (in some specific locations probably more enclined to wave amplification). In this study, we present the results of tsunami modeling for the 1755 event on the French island of Martinique, located in the Lesser Antilles Arc. High resolution bathymetric grids were prepared, including topographic data for the first tens of meters from the coastline, in order to model inundations on several sites of Martinique Island. In order to reproduce as well as possible the wave coastal propagation and amplification, the final grid was prepared taking into account the main coastal features and harbour structures. Model results are checked against historical data in terms of wave arrival, polarity, amplitude and period and they correlate well for Martinique. This study is a contribution to the evaluation of the tele-tsunami impact in the Caribbean Islands due to a source located offshore of Iberia and shows that an 8.5 magnitude earthquake located in the northeastern Atlantic is able to generate a tsunami that could impact the Caribbean Islands. This fact must be taken into account in hazard and risk studies for this area.

  10. 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

  11. Numerical tsunami modeling and the bottom relief

    NASA Astrophysics Data System (ADS)

    Kulikov, E. A.; Gusiakov, V. K.; Ivanova, A. A.; Baranov, B. V.

    2016-11-01

    The effect of the quality of bathymetric data on the accuracy of tsunami-wave field calculation is considered. A review of the history of the numerical tsunami modeling development is presented. Particular emphasis is made on the World Ocean bottom models. It is shown that the modern digital bathymetry maps, for example, GEBCO, do not adequately simulate the sea bottom in numerical models of wave propagation, leading to considerable errors in estimating the maximum tsunami run-ups on the coast.

  12. 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…

  13. 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.

  14. Making and breaking the sediment record - characterising effects of tsunamis, storms and average conditions on dune erosion and recovery: a forward modelling exploration.

    NASA Astrophysics Data System (ADS)

    Roelvink, Dano; Costas, Susana

    2015-04-01

    cases we resolve wave-averaged flows, bed load and suspended load transport and morphology change including avalanching. Results will be presented in terms of both profile change and resulting contribution to stratigraphy, allowing to evaluate the effects of these different building blocks on the stratigraphic record. References: Apotsos, A., G. Gelfenbaum, and B. Jaffe, 2011. Process-based modeling of tsunami inundation and sediment transport, J. Geophys. Res., 116, F01006, doi:10.1029/2010JF001797. Rebêlo, L., Costas, S., Brito, P., Ferraz, M., Prudêncio, M. I. and Burbidge, C., 2013. Imprints of the 1755 tsunami in the Tróia Peninsula shoreline, Portugal In: Conley, D.C., Masselink, G., Russell, P.E. and O'Hare, T.J. (eds.), Proceedings 12th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 814-819, ISSN 0749-0208. Dano Roelvink, Ad Reniers, Ap van Dongeren, Jaap van Thiel de Vries, Robert McCall, Jamie Lescinski. Modelling storm impacts on beaches, dunes and barrier islands. Coastal Engineering, Volume 56, Issues 11-12, November-December 2009, Pages 1133-1152

  15. New Perspective of Tsunami Deposit Investigations: Insight from the 1755 Lisbon Tsunami in Martinique, Lesser Antilles.

    NASA Astrophysics Data System (ADS)

    Roger, J.; Clouard, V.; Moizan, E.

    2014-12-01

    The recent devastating tsunamis having occurred during the last decades have highlighted the essential necessity to deploy operationnal warning systems and educate coastal populations. This could not be prepared correctly without a minimum knowledge about the tsunami history. That is the case of the Lesser Antilles islands, where a few handfuls of tsunamis have been reported over the past 5 centuries, some of them leading to notable destructions and inundations. But the lack of accurate details for most of the historical tsunamis and the limited period during which we could find written information represents an important problem for tsunami hazard assessment in this region. Thus, it is of major necessity to try to find other evidences of past tsunamis by looking for sedimentary deposits. Unfortunately, island tropical environments do not seem to be the best places to keep such deposits burried. In fact, heavy rainfalls, storms, and all other phenomena leading to coastal erosion, and associated to human activities such as intensive sugarcane cultivation in coastal flat lands, could caused the loss of potential tsunami deposits. Lots of places have been accurately investigated within the Lesser Antilles (from Sainte-Lucia to the British Virgin Islands) the last 3 years and nothing convincing has been found. That is when archeaological investigations excavated a 8-cm thick sandy and shelly layer in downtown Fort-de-France (Martinique), wedged between two well-identified layers of human origin (Fig. 1), that we found new hope: this sandy layer has been quickly attributed without any doubt to the 1755 tsunami, using on one hand the information provided by historical reports of the construction sites, and on the other hand by numerical modeling of the tsunami (wave heights, velocity fields, etc.) showing the ability of this transoceanic tsunami to wrap around the island after ~7 hours of propagation, enter Fort-de-France's Bay with enough energy to carry sediments, and

  16. A Pre-2004 Tsunami Deposit in Thailand

    NASA Astrophysics Data System (ADS)

    Jankaew, K.; Choowong, M.; Charoentitirat, T.; Machado, T.; Martin, M. E.; Pailoplee, S.; Phantuwongraj, S.; Napradit, T.; Weerahong, A.; Surakiatchai, P.

    2007-05-01

    A sand layer from a predecessor to the 2004 Indian Ocean tsunami underlies a freshwater marsh on Phra Thong Island, Phang Nga Province, Thailand. At this marsh, about 300 meters from the sea, the 2004 tsunami left a sand layer about 13 cm thick on top of a peaty soil. The previous tsunami deposit, of similar thickness, rests on another peaty soil about 40 cm below present ground surface. It probably correlates with a pre-2004 tsunami deposit previously reported from Phra Thong Island in a web posting by Shigehiro Fujino. Observed in trenches and cores, the pre-2004 deposit begins with a razor-sharp contact with the underlying soil. The sand itself contains no fewer than 6 layers, all horizontal, defined by differences in particle size (fine sand and very fine sand) and by detrital plant fragments. We also noticed pebble-size clasts of peaty soil. These observations come from the vicinity of UTM coordinates 418975E, 1009496N, zone 47. Many of us participated in previous, unsuccessful attempts to find pre-2004 tsunami deposits in Thailand. We hunted for sand sheets between Phuket to the south and Kho Khao Island to the north, on beach-ridge plains disturbed by tin mining and in mangrove swamps. We also checked pristine, grassy beach-ridge plains of Phra Thong Island, the next island north of Kho Khao. None of these environments offer both a host deposit that contrasts with tsunami-laid sand and a lack of disturbance by tin miners, mud lobsters, and real-estate developers.

  17. 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.

  18. Inversion of tsunami height using ionospheric observations. The case of the 2012 Haida Gwaii tsunami

    NASA Astrophysics Data System (ADS)

    Rakoto, V.; Lognonne, P. H.; Rolland, L.

    2014-12-01

    Large and moderate tsunamis generate atmospheric internal gravity waves that are detectable using ionospheric monitoring. Indeed tsunamis of height 2cm and more in open ocean were detected with GPS (Rolland et al. 2010). We present a new method to retrieve the tsunami height from GPS-derived Total Electron Content observations. We present the case of the Mw 7.8 Haida Gwaii earthquake that occured the 28 october 2012 offshore the Queen Charlotte island near the canadian west coast. This event created a moderate tsunami of 4cm offshore the Hawaii archipelago. Equipped with more than 50 receivers it was possible to image the tsunami-induced ionospheric perturbation. First, our forward model leading to the TEC perturbation follows three steps : (1) 3D modeling of the neutral atmosphere perturbation by summation of tsunami-induced gravity waves normal modes. (2) Coupling of the neutral atmosphere perturbation with the ionosphere to retrieve the electron density perturbation. (3) Integration of the electron density perturbation along each satellite-station ray path. Then we compare this results to the data acquired by the Hawaiian GPS network. Finally, we examine the possibility to invert the TEC data in order to retrieve the tsunami height and waveform. For this we investigate the link between the height of tsunamis and the perturbed TEC in the ionosphere.

  19. Modeling tools for the real-time evaluation and historical reconstruction of tsunami events in New Zealand

    NASA Astrophysics Data System (ADS)

    Borrero, J. C.; Greer, D.; Goring, D. G. G.; Power, W. L.

    2014-12-01

    We assess tsunami hazards in New Zealand through a review of historical accounts, analysis of water level and current speed data and detailed numerical modeling. The tsunamis of 2010 (Chile) and 2011 (Japan) were recorded on tide gauges throughout New Zealand, providing a rich water level data set for model comparison and calibration. Furthermore, a current meter at the entrance to Tauranga Harbor also captured these tsunamis providing a unique current speed data set augmented by several concurrent water level records. Analysis of the current data from 2011 shows that although port operations were not adversely affected, tsunami currents may have exceeded thresholds for the navigation of large vessels through the narrow harbor entrance. Harmonic analysis of the current speed data also illustrates the effect of tidal flows on tsunami currents. This information was then used to calibrate numerical models using the ComMIT modeling tool. A sensitivity study for tsunamis generated from around the Pacific Rim indicates the relative hazards from different source regions. Deterministic scenario modeling of significant historical tsunamis provides a quantitative estimate of the expected effects from possible future great earthquakes. These models were tested in April 2014 after the Mw 8.2 earthquake offshore of Iquique, Chile - an event of particular concern given that the August 1868 Arica earthquake generated a tsunami of ~7 m in Lyttelton Harbor as well as runup of up to 10 m in the Chatham Islands. As the April 2014 event unfolded, it was initially unclear if an evacuation or other emergency response would be necessary in New Zealand given that a tsunami was observed and recorded on tide gauges and deep ocean tsunameters close to the source region. Models run in real time, using sources based on inverted tsunameter data and finite fault solutions of the earthquake, suggested that a damaging far-field tsunami was not expected. As a result, emergency response teams and

  20. Effects of different boundary conditions and palaeotopographies on the onshore response of tsunamis in a numerical model - A case study from western Greece

    NASA Astrophysics Data System (ADS)

    Röbke, B. R.; Schüttrumpf, H.; Vött, A.

    2016-08-01

    Hydrodynamic numerical models are essential in modern tsunami hazard assessment. They allow the economical simulation of possible tsunami scenarios for areas at risk and provide reliable and detailed insights into local onshore dynamics. This is especially true when simulations are calibrated with field traces of past tsunami inundation events. Following this approach, the current study focuses on palaeotsunami events indicated by sedimentary and geomorphological field traces in the northern Gulf of Kyparissia (NW Greece). Based on three different digital elevation models (DEM) - reflecting the recent and two palaeotopographies - various tsunami wave constellations according to the solitary and N-wave theory are numerically simulated. The main objective is to investigate the effects of both, different palaeotopographies and boundary conditions on the tsunami onshore response in the numerical model. Tsunami landfall related to N-waves is found to be considerably stronger compared to solitary waves. This phenomenon, known as the N-wave effect, is demonstrated for the first time in a specific study area. Inundation dynamics are even stronger affected by the different palaeotopographies, which is due to substantial vertical crust movements in the northern Gulf of Kyparissia considered in the palaeo-DEMs. By applying different waveforms and palaeotopographies, the model achieves close agreement with field observations, altogether revealing a significant tsunami hazard for the Gulf of Kyparissia, which is in contrast to conventional numerical studies of the area. The marked differences between the presented scenarios emphasise the need to consider a wide variety of possible hydrodynamic boundary conditions and probable topographical conditions in order to find scenarios in plausible accordance with palaeotsunami field traces. Once a plausible scenario is found it can be applied to the recent topography in view of a reliable modern hazard assessment.

  1. Using tsunami deposits to improve assessment of tsunami risk

    USGS Publications Warehouse

    Jaffe, B.E.; Gelfenbaum, G.; ,

    2002-01-01

    In many places in the world the written record of tsunamis is too short to accurately assess the risk of tsunamis. Sedimentary deposits left by tsunamis can be used to extend the record of tsunamis to improve risk assessment. The two primary factors in tsunami risk, tsunami frequency and magnitude, can be addressed through field and modeling studies of tsunami deposits. Recent advances in identification of tsunami deposits and in tsunami sedimentation modeling increase the utility of using tsunami deposits to improve assessment of tsunami risk.

  2. 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

  3. 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.

  4. Modelisation of the impact of tsunamis and free oscillation in French Polynesia

    NASA Astrophysics Data System (ADS)

    Allgeyer, Sébastien; Hébert, Hélène; Madariaga, Raúl

    2010-05-01

    The agitation inside basins (closed or semi-enclosed) depends on the period of the waves which force agitation, reflection and energy dissipation, characteristics of the boundary and the geometrical properties of the basin. When waves continuously enter the basin, they cause abnormal water level fluctuations and unexpected damage if their periods are close to those of free oscillation of the basin. These are called resonant oscillations. The resonant oscillations inside harbors, bays, or other semi-enclosed or closed basins can have a direct influence on the management of harbors, shipping and coastal uses. So, it is important to determine these free oscillations. These resonant characteristics were observed in the Marquesas archipelago (French Polynesia) during the Samoa tsunami of 29/09/2009 (Mw 8.0). They had previously been observed for the tsunamis generated by Kurile earthquakes (November 2006 and January 2007), Chilean and Peruvian earthquakes (August and November 2007). According to the observations of the tsunami produced by the Samoa earthquake, strong amplification and a long duration of water agitation were reported in this archipelago. Observations coming from monitored bays and human reports make this event among the important tsunamis recorded in the Marquesas. In this archipelago there are two monitored bays: the first, located in Hiva Oa Island (Tahauku bay), recorded an amplitude of 40 cm and 2 days of agitation. The second in Nuku Hiva Island (Taihoae bay) had an amplitude of 45 cm and 3 days of agitation. During last century, this archipelago has been frequently hit by several trans-Pacific tsunamis. It is interesting to note that, following different tsunami reports, the bays had different responses depending on the region of the earthquake source. For instance, Tahauku and Atuona, two bays in Hiva Oa Island distant 1 km apart, have different effects depending on the tsunami, as it was observed in 1946 (Aleutian earthquake) and 1960 (Chile

  5. Tsunamis generated by 3D deformable landslides in various scenarios: laboratory experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    McFall, B. C.; Fritz, H. M.; Horrillo, J. J.; Mohammed, F.

    2014-12-01

    Landslide generated tsunamis such as Lituya Bay, Alaska 1958 account for some of highest recorded tsunami runup heights. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by pneumatic pistons down slope. Two different landslide materials are used to study the granulometry effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified with video image processing. The measured landslide and wave parameters are compared between the planar hill slope used in various scenarios and the convex hill slope of the conical island. The energy conversion rates from the landslide motion to the wave train is quantified for the planar and convex hill slopes. The wave runup data on the opposing headland is analyzed and evaluated with wave theories. The measured landslide and tsunami data serve to validate and advance three-dimensional numerical landslide tsunami prediction models. Two 3D Navier-Stokes models were tested, the commercial code FLOW-3D

  6. Comparison Between Slip Distributions of the 2010 Mentawai Earthquake Derived by Two Inversion Modles Based on Tsunami Data

    NASA Astrophysics Data System (ADS)

    li, L.; Huang, Z.

    2013-12-01

    It has been shown that the characteristics of a tsunami wave including wave heights recorded by DARTs in deep sea, waveforms recorded by tide gauges, and runup heights are useful to constrain some earthquake source parameters. In this study, we investigate the slip distribution of the 2010 Mentawai earthquake, a tsunami earthquake that occurred seaward of the southern Mentawai islands of Sumatra, and produced a locally devastating tsunami, with runup commonly in excess of 6 m. As a unique tsunami earthquake case, there is a significant discrepancy between the observed small GPS displacement and the very large tsunami runup (maximum value > 16 m), which cannot be explained by the conventional GPS or seismic inversion model. The goal of this work is to compare the slip distributions of this earthquake inferred from the available waveforms recorded by nearby tide gauges or from the tsunami height and runup data collected in a field survey, using two inversion models. One is based on Green's fuctions technique. The other is based on adjoint method which is an application of optimal control theory. The inversion by Green's functions requires a linear link between data and unknown variables. The adjoint method has the advantage of being able to use either linear or non-linear forward propagation models that can account for non-linear advection and run-up effects. The limitations of these two methods are discussed.

  7. Effects of magnetic islands on bootstrap current in toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Dong, G.; Lin, Z.

    2017-03-01

    The effects of magnetic islands on electron bootstrap current in toroidal plasmas are studied using gyrokinetic simulations. The magnetic islands cause little changes of the bootstrap current level in the banana regime because of trapped electron effects. In the plateau regime, the bootstrap current is completely suppressed at the island centers due to the destruction of trapped electron orbits by collisions and the flattening of pressure profiles by the islands. In the collisional regime, small but finite bootstrap current can exist inside the islands because of the pressure gradients created by large collisional transport across the islands. Finally, simulation results show that the bootstrap current level increases near the island separatrix due to steeper local density gradients.

  8. Earthquake related tsunami hazard along the western coast of Thailand

    NASA Astrophysics Data System (ADS)

    Løvholt, F.; Bungum, H.; Harbitz, C. B.; Glimsdal, S.; Lindholm, C. D.; Pedersen, G.

    2006-11-01

    The primary background for the present study was a project to assist the authorities in Thailand with development of plans for how to deal with the future tsunami risk in both short and long term perspectives, in the wake of the devastating 26 December 2004 Sumatra-Andaman earthquake and tsunami. The study is focussed on defining and analyzing a number of possible future earthquake scenarios (magnitudes 8.5, 8.0 and 7.5) with associated return periods, each one accompanied by specific tsunami modelling. Along the most affected part of the western coast of Thailand, the 2004 tsunami wave caused a maximum water level ranging from 5 to 15 m above mean sea level. These levels and their spatial distributions have been confirmed by detailed numerical simulations. The applied earthquake source is developed based on available seismological and geodetic inversions, and the simulation using the source as initial condition agree well with sea level records and run-up observations. A conclusion from the study is that another megathrust earthquake generating a tsunami affecting the coastline of western Thailand is not likely to occur again for several hundred years. This is in part based on the assumption that the Southern Andaman Microplate Boundary near the Simeulue Islands constitutes a geologic barrier that will prohibit significant rupture across it, and in part on the decreasing subduction rates north of the Banda Ache region. It is also concluded that the largest credible earthquake to be prepared for along the part of the Sunda-Andaman arc that could affect Thailand, is within the next 50-100 years an earthquake of magnitude 8.5, which is expected to occur with more spatial and temporal irregularity than the megathrust events. Numerical simulations have shown such earthquakes to cause tsunamis with maximum water levels up to 1.5-2.0 m along the western coast of Thailand, possibly 2.5-3.0 m on a high tide. However, in a longer time perspective (say more than 50-100 years

  9. Cerebral Small Vessel Disease and Arterial Stiffness: Tsunami Effect in the Brain?

    PubMed Central

    Saji, Naoki; Toba, Kenji; Sakurai, Takashi

    2016-01-01

    Background Cerebral small vessel diseases, including silent lacunar infarcts, white matter hyperintensities, and microbleeds, pose a risk for cerebrovascular disease, cognitive impairment, and the geriatric syndrome via effects on arterial stiffness. However, the vascular, physiological, and metabolic roles of arterial stiffness in cerebral small vessel diseases remain unclear. Summary Arterial stiffness can be assessed using various indicators such as the ankle-brachial index, pulse wave velocity, cardio-ankle vascular index, and augmentation index. Arterial stiffness is independently associated with all components of cerebral small vessel disease including silent lacunar infarcts, white matter hyperintensities, and microbleeds, although there are some methodological differences between the various surrogate markers. Evidence of arterial stiffness indicates microvessel arteriosclerosis presenting with vascular endothelial dysfunction. Further, vascular narrowing due to atherosclerosis and vascular stiffness due to lipohyalinosis can accelerate the pulse waves. This hemodynamic stress, pulsatile pressure, or blood pressure variability can cause a ‘tsunami effect’ towards the cerebral parenchyma and lead to cerebral small vessel disease. Previous studies have shown that silent lacunar infarcts and white matter hyperintensities are strongly associated with arterial stiffness. However, the association between microbleeds and arterial stiffness remains controversial, as there are two vessel mechanisms related to microbleeds: cerebral amyloid angiopathy and hypertensive small vessel disease. Key Messages Cerebral small vessel disease with associated arterial stiffness is a risk factor for silent cerebral lesions, stroke, and cognitive impairment. Improvement of the living environment, management of risk factors, and innovation and development of novel drugs that improve arterial stiffness may suppress the progression of cerebral small vessel disease, and may reduce

  10. 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

  11. National Geophysical Data Center Tsunami Data Archive

    NASA Astrophysics Data System (ADS)

    Stroker, K. J.; Dunbar, P. K.; Brocko, R.

    2008-12-01

    NOAA's National Geophysical Data Center (NGDC) and co-located World Data Center for Geophysics and Marine Geology long-term tsunami data archive provides data and derived products essential for tsunami hazard assessment, forecast and warning, inundation modeling, preparedness, mitigation, education, and research. As a result of NOAA's efforts to strengthen its tsunami activities, the long-term tsunami data archive has grown from less than 5 gigabyte in 2004 to more than 2 terabytes in 2008. The types of data archived for tsunami research and operation activities have also expanded in fulfillment of the P.L. 109-424. The archive now consists of: global historical tsunami, significant earthquake and significant volcanic eruptions database; global tsunami deposits and proxies database; reference database; damage photos; coastal water-level data (i.e. digital tide gauge data and marigrams on microfiche); bottom pressure recorder (BPR) data as collected by Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys. The tsunami data archive comes from a wide variety of data providers and sources. These include the NOAA Tsunami Warning Centers, NOAA National Data Buoy Center, NOAA National Ocean Service, IOC/NOAA International Tsunami Information Center, NOAA Pacific Marine Environmental Laboratory, U.S. Geological Survey, tsunami catalogs, reconnaissance reports, journal articles, newspaper articles, internet web pages, and email. NGDC has been active in the management of some of these data for more than 50 years while other data management efforts are more recent. These data are openly available, either directly on-line or by contacting NGDC. All of the NGDC tsunami and related databases are stored in a relational database management system. These data are accessible over the Web as tables, reports, and interactive maps. The maps provide integrated web-based GIS access to individual GIS layers including tsunami sources, tsunami effects, significant earthquakes

  12. A Possible Tohoku-Magnitude Tsunami Along The Alaska Peninsula, The 1946 Scotch Cap Tsunami

    NASA Astrophysics Data System (ADS)

    Miller, J. J.; von Huene, R.

    2013-12-01

    At Unimak Pass, Alaska, a tsunami in 1946 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 5 seismic lines. One line, processed through prestack depth migration, crosses a 10 x 15 km and 800 m high hill presumed previously to be basement, but instead is comprised 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 m 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.

  13. Assessment of the Initial Response from Tsunami Monitoring Services Provided to the Northeastern Caribbean

    NASA Astrophysics Data System (ADS)

    Soto-Cordero, L.; Meltzer, A.

    2014-12-01

    A mag 6.4 earthquake offshore northern Puerto Rico earlier this year (1/13/14) is a reminder of the high risk of earthquakes and tsunamis in the northeastern Caribbean. Had the magnitude of this event been 0.1 larger (M 6.5) a tsunami warning would have been issued for the Puerto Rico-Virgin Islands (PRVI) region based on the West Coast Alaska Tsunami Warning Center (WCATWC) and Puerto Rico Seismic Network (PRSN) response procedures at the time. Such an alert level would have led local authorities to issue evacuation orders for all PRVI coastal areas. Since the number of deaths associated with tsunamis in the Caribbean region is greater than the total casualties from tsunamis in the entire US (including Hawaii and Alaska coasts) having an effective and redundant warning system is critical in order to save lives and to minimize false alarms that could result in significant economic costs and loss of confidence of Caribbean residents. We are evaluating three fundamental components of tsunami monitoring protocols currently in place in the northeastern Caribbean: 1) preliminary earthquake parameters (used to determine the potential that a tsunami will be generated and the basis of tsunami alert levels), 2) adequacy of the tsunami alert levels, and 3) tsunami message dissemination. We compiled a catalog of earthquake locations (2007-2014) and dissemination times from the PTWC, WCATWC and NEIC (final locations). The events were classified into 3 categories: local [17°-20°N, 63.5°-69°W], regional (Caribbean basin) and distant/teleseismic (Atlantic basin). A total of 104 local earthquakes, 31 regional and 25 distant events were analyzed. We found that in general preliminary epicentral locations have an accuracy of 40 km. 64% of local events were located with an accuracy of 20 km. The depth accuracy of local events shallower than 50 km, regional and distant earthquakes is usually smaller than 30 km. For deeper local events the error distribution shows more variability

  14. Northern Caribbean Tsunami Hazard: Earthquake and Gravity Source Contribution of the Tsunami of 2010 in Haïti

    NASA Astrophysics Data System (ADS)

    Poupardin, Adrien; Hébert, Hélène; Calais, Eric; Gailler, Audrey

    2015-04-01

    The Mw 7 earthquake of January 12, 2010, in Haïti was followed by a tsunami with wave heights reaching 3 m in some locations (Grand Goâve, Jacmel) on either side of the Presqu'Ile du Sud where the event took place. The tsunami was also recorded at DART buoy 42407 (about 600 km southeast of the earthquake source) and at a tide gauge in Santo Domingo (Dominican Republic). In the hours following the event, the National Earthquake Information Center (NEIC) suggested rupture of a south-dipping segment of the Enriquillo-Plantain Garden fault (EPGF). Fritz et al. (2013) used the NEIC source model to simulate the tsunami height and match coastal run-up measurements and DART data by (1) increasing coseismic slip on the EPGF while keeping a constant Mo by scaling the regional rigidity, and (2) invoking a coastal submarine landslide in addition to ground motion. Since then, several studies have considerably improved our understanding of the 2010 Haiti earthquake source using GPS, InSAR, seismological, geological, and/or teleseismic data (Meng et al., 2012; Hayes et al., 2010, Symithe et al., 2013). All show that rupture occurred on a north-dipping blind fault (Leogâne fault) with 1/3 of its moment expressed by reverse motion and up to 60 cm of coastal uplift. Here we revisit the January 12, 2010 Haiti tsunami by modeling runup heights, DART, and tide gauge observations using these recent source models as input parameters. We propagate the tsunami using a non linear shallow water tsunami model able to account for the shoaling effect thanks to imbricated bathymetric grids. Simulations indicate run-up heights much lower than observed (1) in the Grand Goâve Bay, consistent with the hypoythesis of a landslide-triggered tsunami at this location, (2) along the southern coast of Hispaniola and at the DART buoy, closest to observations however when using Symithe et al.'s source model. We also find wave heights up to 1 m in Port-au-Prince (harbor and coastal shantytowns) when using

  15. Tsunami: Hope in the Midst of Disaster

    ERIC Educational Resources Information Center

    Thirumurthy, Vidya; Uma, V.; Muthuram, R. N.

    2008-01-01

    The lives of many were changed forever when a tsunami struck on the morning of December 26, 2004, as a result of an earthquake off the coast of Indonesia registering 9.0 on the Richter scale. Aftershocks in the nearby Andaman and Nicobar Islands sent waves of fear among the survivors, further debilitating their spirits. The aim of this article is…

  16. Tsunami asymptotics

    NASA Astrophysics Data System (ADS)

    Berry, M. V.

    2005-01-01

    By applying the technique of uniform asymptotic approximation to the oscillatory integrals representing tsunami wave profiles, the form of the travelling wave far from the source is calculated for arbitrary initial disturbances. The approximations reproduce the entire profiles very accurately, from the front to the tail, and their numerical computation is much faster than that of the oscillatory integrals. For one-dimensional propagation, the uniform asymptotics involve Airy functions and their derivatives; for two-dimensional propagation, the uniform asymptotics involve products of these functions. Separate analyses are required when the initial disturbance is specified as surface elevation or surface velocity as functions of position, and when these functions are even or odd. 'There was an awful rainbow once in heaven' (John Keats, 1820)

  17. 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.

  18. Accurate numerical simulation of the far-field tsunami caused by the 2011 Tohoku earthquake, including the effects of Boussinesq dispersion, seawater density stratification, elastic loading, and gravitational potential change

    NASA Astrophysics Data System (ADS)

    Baba, Toshitaka; Allgeyer, Sebastien; Hossen, Jakir; Cummins, Phil R.; Tsushima, Hiroaki; Imai, Kentaro; Yamashita, Kei; Kato, Toshihiro

    2017-03-01

    In this study, we considered the accurate calculation of far-field tsunami waveforms by using the shallow water equations and accounting for the effects of Boussinesq dispersion, seawater density stratification, elastic loading, and gravitational potential change in a finite difference scheme. By comparing numerical simulations that included and excluded each of these effects with the observed waveforms of the 2011 Tohoku tsunami, we found that all of these effects are significant and resolvable in the far field by the current generation of deep ocean-bottom pressure gauges. Our calculations using previously published, high-resolution models of the 2011 Tohoku tsunami source exhibited excellent agreement with the observed waveforms to a degree that has previously been possible only with near-field or regional observations. We suggest that the ability to model far-field tsunamis with high accuracy has important implications for tsunami source and hazard studies.

  19. Historical tsunami in the Azores archipelago (Portugal)

    NASA Astrophysics Data System (ADS)

    Andrade, C.; Borges, P.; Freitas, M. C.

    2006-08-01

    Because of its exposed northern mid-Atlantic location, morphology and plate-tectonics setting, the Azores Archipelago is highly vulnerable to tsunami hazards associated with landslides and seismic or volcanic triggers, local or distal. Critical examination of available data - written accounts and geologic evidence - indicates that, since the settlement of the archipelago in the 15th century, at least 23 tsunami have struck Azorean coastal zones. Most of the recorded tsunami are generated by earthquakes. The highest known run-up (11-15 m) was recorded on 1 November 1755 at Terceira Island, corresponding to an event of intensity VII-VIII (damaging-heavily damaging) on the Papadopolous-Imamura scale. To date, eruptive activity, while relatively frequent in the Azores, does not appear to have generated destructive tsunami. However, this apparent paucity of volcanogenic tsunami in the historical record may be misleading because of limited instrumental and documentary data, and small source-volumes released during historical eruptions. The latter are in contrast with the geological record of massive pyroclastic flows and caldera explosions with potential to generate high-magnitude tsunami, predating settlement. In addition, limited evidence suggests that submarine landslides from unstable volcano flanks may have also triggered some damaging tsunamigenic floods that perhaps were erroneously attributed to intense storms. The lack of destructive tsunami since the mid-18th century has led to governmental complacency and public disinterest in the Azores, as demonstrated by the fact that existing emergency regulations concerning seismic events in the Azores Autonomous Region make no mention of tsunami and their attendant hazards. We suspect that the coastal fringe of the Azores may well preserve a sedimentary record of some past tsunamigenic flooding events. Geological field studies must be accelerated to expand the existing database to include prehistoric events

  20. Tsunami Detection Systems for International Requirements

    NASA Astrophysics Data System (ADS)

    Lawson, R. A.

    2007-12-01

    recognize these characteristics, and then immediately alerts a tsunami warning center through the communications buoy when the processor senses one of these waves. In addition to the tsunami detection buoy system, an end-to-end tsunami warning system was developed that builds upon the country's existing disaster warning infrastructure. This warning system includes 1) components that receive, process, and analyze buoy, seismic and tide gauge data; 2) predictive tools and a consequence assessment tool set to provide decision support; 3) operation center design and implementation; and 4) tsunami buoy operations and maintenance support. The first buoy was deployed Oct. 25, 2006, approximately 200 nautical miles west of San Diego in 3,800 meters of water. Just three weeks later, it was put to the test during an actual tsunami event. On Nov. 15, 2006, an 8.3 magnitude earthquake rocked the Kuril Islands, located between Japan and the Kamchatka Peninsula of Russia. That quake generated a small tsunami. Waves from the tsunami propagated approximately 4,000 nautical miles across the Pacific Ocean in about nine hours-- a speed of about 445 nautical miles per hour when this commercial buoy first detected them. Throughout that event, the tsunami buoy system showed excellent correlation with data collected by a NOAA DART buoy located 28 nautical miles north of it. Subsequent analysis revealed that the STB matched DART operational capabilities and performed flawlessly. The buoy proved its capabilities again on Jan. 13, 2007, when an 8.1 magnitude earthquake occurred in the same region, and the STB detected the seismic event. As a result of the successes of this entire project, SAIC recently applied for and received a license from NOAA to build DART systems.

  1. Japan: Tsunami Flooding

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Lingering Floods from Tohoku-oki Earthquake Tsunami     View Larger Image The March 11, 2011 Tohoku-oki earthquake triggered a deadly and destructive tsunami whose impacts were felt ...

  2. Tsunamis: Water Quality

    MedlinePlus

    ... Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Tsunamis: Water Quality Language: English Español (Spanish) Recommend on Facebook ... about testing should be directed to local authorities. Water for Drinking, Cooking, and Personal Hygiene Safe water ...

  3. Climate change: Effects on reef island resources

    SciTech Connect

    Oberdorfer, J.A.; Buddemeier, R.W.

    1988-06-27

    The salinity, depth, quantity, and reliability of fresh groundwater resources on coral reef islands and coastlines are environmentally important parameters. Groundwater influences or controls the terrestrial flora, salinity, and nutrient levels in the near-shore benthic environment, the rate and nature of sediment diagenesis, and the density of human habitation. Data from a number of Indo-Pacific reef islands suggest that freshwater inventory is a function of rainfall and island dimensions. A numerical model (SUTRA) has been used to simulate the responses of atoll island groundwater to changes in recharge (precipitation), sea level, and loss of island area due to flooding. The model has been calibrated for Enjebi Island, Enewetak Atoll, where a moderately permeable, water-table aquifer overlies a high-permeability formation. Total freshwater inventory is a monotonic but nonlinear function of recharge. If recharge and island area are constant, rising sea level increases the inventory of fresh water by increasing the useful volume of the aquifer above the high-permeability zone. Flooding of land area reduces the total freshwater inventory approximately in proportion to the loss of recharge area. The most significant results of the model simulation, however, are the findings that the inventory of low-salinity water (and by extrapolation, potable water) is disproportionately sensitive to changes in recharge, island dimensions, or recharge. Island freshwater resources may therefore be unexpectedly vulnerable to climate change.

  4. Volcanic tsunamis and prehistoric cultural transitions in Cook Inlet, Alaska

    USGS Publications Warehouse

    Beget, J.; Gardner, C.; Davis, K.

    2008-01-01

    The 1883 eruption of Augustine Volcano produced a tsunami when a debris avalanche traveled into the waters of Cook Inlet. Older debris avalanches and coeval paleotsunami deposits from sites around Cook Inlet record several older volcanic tsunamis. A debris avalanche into the sea on the west side of Augustine Island ca. 450??years ago produced a wave that affected areas 17??m above high tide on Augustine Island. A large volcanic tsunami was generated by a debris avalanche on the east side of Augustine Island ca. 1600??yr BP, and affected areas more than 7??m above high tide at distances of 80??km from the volcano on the Kenai Peninsula. A tsunami deposit dated to ca. 3600??yr BP is tentatively correlated with a southward directed collapse of the summit of Redoubt Volcano, although little is known about the magnitude of the tsunami. The 1600??yr BP tsunami from Augustine Volcano occurred about the same time as the collapse of the well-developed Kachemak culture in the southern Cook Inlet area, suggesting a link between volcanic tsunamis and prehistoric cultural changes in this region of Alaska. ?? 2008 Elsevier B.V.

  5. Issues in Indonesia's tsunami disaster management system revealed after the 2004 Sumatra event

    NASA Astrophysics Data System (ADS)

    Sugimoto, M.; Koyama, A.; Sun, H.; Kang, I.; Arakawa, T.; Kobayashi, J.; Nagata, M.; Nakanishi, R.; Nakano, M.; Noguchi, S.

    2014-12-01

    During the 2004 Indian Ocean Tsunami, Indonesia had the largest number of casualties around 170,000. International society has supported tsunami early warning system, disaster management and disaster education for Indonesia. The past ten years saw several tsunamis in Indonesia after the 2004 Indian Ocean tsunami. Construction of tsunami early warning system was not in time the 2006 Pangandaran tsunami in Jawa Island. On the other hand, tsunami science has been developed for this decade. Tsunami early warning system has been developed by deep ocean pressure gauges (DART system), coastal tide gauges, GPS buoys and so on. Tsunami folklore has been collected and used education and connected with tsunami deposit. However, the tsunami early warning system and other science application were not widely used at once in Indonesia. GPS buoys were stolen by fishery people. One tsunami evacuation building are not used for evacuation by local people in Aceh Sumatra Island in 2012 though locations of the buildings were selected by scientific numerical simulation. Big panic and trafic accidents occurred by M8.6 earthquake in Aceh in April 2012 and reveal lack of disaster management planning in urban planning during reconstruction (Fig.1: Trafic jam in Banda Aceh, source MSN news photo). In addition to this, the 2011 Tohoku earthquake and tsunami reveal fragilities tsunami preparedness. How should we decide to use the tsunami science? We research field situation in Aceh the after 10 years past from the 2004 Sumatra event. This presentation discusses issues of the gap between tsunami science and operations through field research in Aceh now.

  6. Tsunamis and splay fault dynamics

    USGS Publications Warehouse

    Wendt, J.; Oglesby, D.D.; Geist, E.L.

    2009-01-01

    The geometry of a fault system can have significant effects on tsunami generation, but most tsunami models to date have not investigated the dynamic processes that determine which path rupture will take in a complex fault system. To gain insight into this problem, we use the 3D finite element method to model the dynamics of a plate boundary/splay fault system. We use the resulting ground deformation as a time-dependent boundary condition for a 2D shallow-water hydrodynamic tsunami calculation. We find that if me stress distribution is homogeneous, rupture remains on the plate boundary thrust. When a barrier is introduced along the strike of the plate boundary thrust, rupture propagates to the splay faults, and produces a significantly larger tsunami man in the homogeneous case. The results have implications for the dynamics of megathrust earthquakes, and also suggest mat dynamic earthquake modeling may be a useful tool in tsunami researcn. Copyright 2009 by the American Geophysical Union.

  7. Characteristics of the 2011 Tohoku Tsunami and introduction of two level tsunamis for tsunami disaster mitigation

    PubMed Central

    SATO, Shinji

    2015-01-01

    Characteristics of the 2011 Tohoku Tsunami have been revealed by collaborative tsunami surveys extensively performed under the coordination of the Joint Tsunami Survey Group. The complex behaviors of the mega-tsunami were characterized by the unprecedented scale and the low occurrence frequency. The limitation and the performance of tsunami countermeasures were described on the basis of tsunami surveys, laboratory experiments and numerical analyses. These findings contributed to the introduction of two-level tsunami hazards to establish a new strategy for tsunami disaster mitigation, combining structure-based flood protection designed by the Level-1 tsunami and non-structure-based damage reduction planned by the Level-2 tsunami. PMID:26062739

  8. Characteristics of the 2011 Tohoku Tsunami and introduction of two level tsunamis for tsunami disaster mitigation.

    PubMed

    Sato, Shinji

    2015-01-01

    Characteristics of the 2011 Tohoku Tsunami have been revealed by collaborative tsunami surveys extensively performed under the coordination of the Joint Tsunami Survey Group. The complex behaviors of the mega-tsunami were characterized by the unprecedented scale and the low occurrence frequency. The limitation and the performance of tsunami countermeasures were described on the basis of tsunami surveys, laboratory experiments and numerical analyses. These findings contributed to the introduction of two-level tsunami hazards to establish a new strategy for tsunami disaster mitigation, combining structure-based flood protection designed by the Level-1 tsunami and non-structure-based damage reduction planned by the Level-2 tsunami.

  9. 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.

  10. Tsunami heights and damage along the Myanmar coast from the December 2004 Sumatra-Andaman earthquake

    NASA Astrophysics Data System (ADS)

    Satake, Kenji; Aung, Than Tin; Sawai, Yuki; Okamura, Yukinobu; Win, Kyaw Soe; Swe, Win; Swe, Chit; Swe, Tint Lwin; Tun, Soe Thura; Soe, Maung Maung; Oo, Thant Zin; Zaw, Saw Htwe

    2006-02-01

    The tsunami heights from the 2004 Sumatra-Andaman earthquake were between 0.4 and 2.9 m along the Myanmar coast, according to our post tsunami survey at 22 sites in Ayeyarwaddy Delta and the Taninthayi coast. Interviews to coastal residents indicate that the tsunami heights were lower than high tide level in rainy season, probably by storm surge. They also testified that the arrival times were between 2 and 5.5 hours after the earthquake but the reliability may be low because nobody felt ground shaking. Much smaller tsunami than the neighboring Thai coast, where the tsunami heights were 5 to 20 m, explains relatively slighter tsunami damage in Myanmar; the casualties were reported as 71, compared to about 8300 in Thailand. The smaller tsunami was probably due to the fact that the main tsunami source did not extend to Andaman Islands. The tsunami travel times and maximum heights computed from a 700 km long source are basically consistent with the observations. For a nearby tsunami source, the tsunami hazard would be more significant in Myanmar, because coastal houses are unprotected for tsunamis and no infrastructure exists to disseminate tsunami warning information.

  11. Evaluation of the effectiveness and salt stress of Pteris vittata in the remediation of arsenic contamination caused by tsunami sediments.

    PubMed

    Sugawara, Kazuki; Kobayashi, Akihiro; Endo, Ginro; Hatayama, Masayoshi; Inoue, Chihiro

    2014-01-01

    On March 11, 2011, one of the negative effects of the tsunami phenomenon that devastated the Pacific coast of the Tohoku district in Japan was the deposition of a wide range of arsenic (As) contamination to the soil. To remediate such a huge area of contamination, phytoremediation by Pteris vittata, an As-hyperaccumulator, was considered. To evaluate the efficacy of applying P. vittata to the area, the salt tolerance of P. vittata and the phytoextraction of As from soil samples were investigated. For the salt tolerance test, spore germination was considerably decreased at an NaCl level of more than 100 mM. At 200 mM, the gametophytes exhibited a morphological defect. Furthermore, the growth inhibition of P. vittata was observed with a salinity that corresponded to 66.2 mS/m of electric conductivity (EC) in the soil. A laboratory phytoremediation experiment was conducted using As-contaminated soils for 166 days. P. vittata grew and accumulated As at 264 mg/kg-DW into the shoots. Consequently, the soluble As in the soil was evidently decreased. These results showed that P. vittata was applicable to the phytoremediation of As-contaminated soil with low salinity as with the contamination caused by the 2011 tsunami.

  12. A fast global tsunami modeling suite as a trans-oceanic tsunami hazard prediction and mitigation tool

    NASA Astrophysics Data System (ADS)

    Mohammed, F.; Li, S.; Jalali Farahani, R.; Williams, C. R.; Astill, S.; Wilson, P. S.; B, S.; Lee, R.

    2014-12-01

    The past decade has been witness to two mega-tsunami events, 2004 Indian ocean tsunami and 2011 Japan tsunami and multiple major tsunami events; 2006 Java, Kuril Islands, 2007 Solomon Islands, 2009 Samoa and 2010 Chile, to name a few. These events generated both local and far field tsunami inundations with runup ranging from a few meters to around 40 m in the coastal impact regions. With a majority of the coastal population at risk, there is need for a sophisticated outlook towards catastrophe risk estimation and a quick mitigation response. At the same time tools and information are needed to aid advanced tsunami hazard prediction. There is an increased need for insurers, reinsurers and Federal hazard management agencies to quantify coastal inundations and vulnerability of coastal habitat to tsunami inundations. A novel tool is developed to model local and far-field tsunami generation, propagation and inundation to estimate tsunami hazards. The tool is a combination of the NOAA MOST propagation database and an efficient and fast GPU (Graphical Processing Unit)-based non-linear shallow water wave model solver. The tsunamigenic seismic sources are mapped on to the NOAA unit source distribution along subduction zones in the ocean basin. Slip models are defined for tsunamigenic seismic sources through a slip distribution on the unit sources while maintaining limits of fault areas. A GPU based finite volume solver is used to simulate non-linear shallow water wave propagation, inundation and runup. Deformation on the unit sources provide initial conditions for modeling local impacts, while the wave history from propagation database provides boundary conditions for far field impacts. The modeling suite provides good agreement with basins for basin wide tsunami propagation to validate local and far field tsunami inundations.

  13. Heat Islands

    EPA Pesticide Factsheets

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  14. Numerical modelling of the 28 October 2011 Haida Gwaii tsunami

    NASA Astrophysics Data System (ADS)

    Fine, I.; Cherniawsky, J. Y.; Thomson, R.

    2013-12-01

    On October 28, 2012, a strong (Mw=7.7) earthquake occurred offshore of Moresby Island, Haida Gwaii (formerly the Queen Charlotte Islands). The earthquake generated a trans-Pacific tsunami observed from New Zealand to Alaska. We used an updated finite-fault model of the earthquake of Hayes (2013) to estimate the tsunami source. The location of this source was subsequently adjusted using tsunami waveforms recorded by bottom pressure recorders at NOAA DART stations and on the NEPTUNE Canada cabled observatory. The adjusted source was then used in a high-resolution model of tsunami wave propagation towards the bays and inlets of Moresby Island. According to the model, tsunami run-up in some bays would have been higher than 7 m. Subsequent post-surveys at several Moresby Island sites were undertaken in mid-November of 2012 and in June 2013, directed in part by the numerical model results. These surveys showed clear evidence of recent tsunami run-up of more than 8 m above the tide at specific coastal embayments, in good agreement with the numerical model results.

  15. New Tsunami Inundation Maps for California

    NASA Astrophysics Data System (ADS)

    Barberopoulou, Aggeliki; Borrero, Jose; Uslu, Burak; Kanoglu, Utku; Synolakis, Costas

    2010-05-01

    California is the first US State to complete its tsunami inundation mapping. A new generation of tsunami inundation maps is now available for 17 coastal counties.. The new maps offer improved coverage for many areas, they are based on the most recent descriptions of potential tsunami farfield and nearfield sources and use the best available bathymetric and topographic data for modelling. The need for new tsunami maps for California became clear since Synolakis et al (1998) described how inundation projections derived with inundation models that fully calculate the wave evolution over dry land can be as high as twice the values predicted with earlier threshold models, for tsunamis originating from tectonic source. Since the 1998 Papua New Guinea tsunami when the hazard from offshore submarine landslides was better understood (Bardet et al, 2003), the State of California funded the development of the first generation of maps, based on local tectonic and landslide sources. Most of the hazard was dominated by offshore landslides, whose return period remains unknown but is believed to be higher than 1000 years for any given locale, at least in Southern California. The new generation of maps incorporates local and distant scenarios. The partnership between the Tsunami Research Center at USC, the California Emergency Management Agency and the California Seismic Safety Commission let the State to be the first among all US States to complete the maps. (Exceptions include the offshore islands and Newport Beach, where higher resolution maps are under way). The maps were produced with the lowest cost per mile of coastline, per resident or per map than all other States, because of the seamless integration of the USC and NOAA databases and the use of the MOST model. They are a significant improvement over earlier map generations. As part of a continuous improvement in response, mitigation and planning and community education, the California inundation maps can contribute in

  16. Effects of 2010 Hurricane Earl amidst geologic evidence for greater overwash at Anegada, British Virgin Islands

    NASA Astrophysics Data System (ADS)

    Atwater, B. F.; Fuentes, Z.; Halley, R. B.; Ten Brink, U. S.; Tuttle, M. P.

    2014-03-01

    A post-hurricane survey of a Caribbean island affords comparisons with geologic evidence for greater overwash at the same place. This comparison, though of limited application to other places, helps calibrate coastal geology for assessment of earthquake and tsunami potential along the Antilles Subduction Zone. The surveyed island, Anegada, is 120 km south of the Puerto Rico Trench and is near the paths of hurricanes Donna (1960) and Earl (2010), which were at or near category 4 when at closest approach. The survey focused on Earl's geologic effects, related them to the surge from Hurricane Donna, and compared them further with erosional and depositional signs of southward overwash from the Atlantic Ocean that dates to 1200-1450 AD and to 1650-1800 AD. The main finding is that the geologic effects of these earlier events dwarf those of the recent hurricanes. Hurricane Earl's geologic effects at Anegada, observed mainly in 2011, were limited to wrack deposition along many of the island's shores and salt ponds, accretion of small washover (spillover) fans on the south shore, and the suspension and deposition of microbial material from interior salt ponds. Earl's most widespread deposit at Anegada, the microbial detritus, was abundantly juxtaposed with evidence for catastrophic overwash in prior centuries. The microbial detritus formed an extensive coating up to 2 cm thick that extended into breaches in beach-ridge plains of the island's north shore, onto playas that are underlain by a sand-and-shell sheet that extends as much as 1.5 km southward from the north shore, and among southward-strewn limestone boulders pendant to outcrops as much as 1 km inland. Earl's spillover fans also contrast with a sand-and-shell sheet, which was dated previously to 1650-1800, by being limited to the island's south shore and by extending inland a few tens of meters at most. These findings complement those reported in this issue by Michaela Spiske and Robert Halley (Spiske and Halley

  17. 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

    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.

  18. Methodology for local tsunami hazard mapping and assessment for Mediterranean and North Atlantic coasts, SCHEMA Project (EC FP6).

    NASA Astrophysics Data System (ADS)

    Guillande, R.; Gardi, A.; Salaun, T.; Laboudigue, A.; Koscielny, M.; Tinti, S.; Silva, A.; Novikova, T.; Lesne, O.; Mangin, A.

    2009-04-01

    At local level, tsunami hazard is usually described by inundations maps providing inundation depths and extension. However, many other parameters such as eddies, fast currents, erosion, receding seas, impact of breaking waves have effects on natural and human environment. Modern tsunami modelling tools can provide a part of these informations and allow producing hazard maps with multiple parameters. Nevertheless, a benchmark is necessary to qualify the capacity of the models for traducing the reality. A comparison of five modelling tools has been undertaken in the framework of SCHEMA Project, using a single set of data on an Island of Seychelles. A simulation of the 26th December 2004 Indian tsunami has been carried out on each model and simulated tide gauges have been compared to the Point la Rue Tide recorded tide gauge close to the Airport of Mahé Island. The inundation extension is also compared to the mapped Dec 2004 inundation. The results show that each model represent generally well the first waves for 2 or 3 hours but they almost all loose compatibility with reality beyond, whereas the real effects were recorded during 24 hours on the Seychelles. The modelled inundation can also vary significantly and introduce a high level of uncertainty on inundation depth and extents. This sets the difficulty to have trust in models simulations for long duration events especially in the aim of emergency planning after warning or confirmation of a real tsunami. After a first stage of qualification of models, a set of hazard parameters are produced for a given tsunami source. Each of these factors is represented by a map and simulated tide gauges complete the set of information describing the hazard. The operational hazard mapping scales ranging generally from 1/25000 to 1/5000 require using a higher ground resolution than what is generally used in most tsunami modelling software's. A ground resolution around 10m appears to be an optimal target. The uncertainty level is

  19. 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

    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.

  20. 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

  1. Ofu and Ologesa survey of the 29 September 2009 tsunami

    NASA Astrophysics Data System (ADS)

    Foteinis, S.; Synolakis, C.; Titov, V. V.

    2009-12-01

    On 29 September 2009 an Mw~8.0 earthquake struck the Samoan Islands generating a tsunami at least 189 deaths and substantial damage to many coastal infrastructure. An incarnation of the ITST surveyed the impacted region between 4 Oct and 11 Oct measuring inundation per the protocol discussed in Synolakis and Okal (2005). We report here survey results from Ofu and Ologesa, two sparsely populated adjacent islands connected with a bridge. No human casualties were reported. Buildings did not sustain substantial damage, due to light construction materials and open wood frame construction. The strongest effects of the tsunami were recorded in the northern part of Ofu, with runup ranging to 6.1m, with 50m inundation. The longest inundation distance was 74 m (3m runup), in Ofu village. The runup at the airport was 3.9m and inundation 27m. Near the bridge there is motel where runup reached 5.1m with 50m inundation. On the north of Ologessa at Sili village, runup ranged up to 4m with inundation less than 25m. Iin Ologessa village, runup ranged from 2.7m to 4.4m and inundation from 5 to 55m. By serendipity, the team of surveyors experienced a tsunami warning while working in a fairly vulnerable locale. The warning resulted from the 7 October 2009 Mw ~7.6, off Vanuatu . The evacuation message was broadcast by a passing police vehicle in the sole road connecting Ofu and the Ologesa. There was no information where to evacuate to. With the exception of a school bus that drove children from the sole school of the island, evacuations were orderly with care for the elderly and special needs neighbors, although the latter were delayed for tens of minutes on some neighborhoods. In this regard, had there been a real local tsunami, the school bus would had been swept away as allegedly happened in Poloa. For over three hours, there was no further information provided, and residents relied on unofficial reports from radio stations in Samoa relating that there had been no tsunami generated

  2. Modelling the tsunami free oscillations in the Marquesas (French Polynesia)

    NASA Astrophysics Data System (ADS)

    Allgeyer, S.; Hébert, H.; Madariaga, R.

    2013-06-01

    The tsunami resonance inside basins (closed or semi-enclosed) depends on the period of the incident waves, reflection and energy dissipation, characteristics of the boundary and the geometry of the basin. When waves continuously enter the basin, they cause abnormal water level fluctuations and produced damage if their periods are close to the periods of free oscillation of the basin. These resonant oscillations inside harbours, bays, or other semi-enclosed or closed basins can have a direct influence on the management of harbours, shipping and coastal uses. So, it is important to determine these free oscillations. These resonant characteristics have been observed in the Marquesas, an archipelago prone to tsunami amplification, during the last three tsunamis (Samoa 2009, Maule 2010, Tohoku 2011). These events were recorded by the two tide gauges located in the Marquesas. In this archipelago, there are two monitored bays : the first one is located in Hiva Oa Island (Tahauku Bay) and the second in Nuku Hiva Island (Taihoae Bay). For all these tsunamis, more than 3 d of water tidal resonance were recorded. In this work, we make a free oscillation analysis of the Marquesas Archipelago using real tide gauge data, simulated tsunami data and theoretical computations. During the last century, this archipelago was hit by several trans-Pacific tsunamis. It is interesting to note that, following different tsunami reports the bays responded differently depending on the earthquake source region. For example, Tahauku and Atuona, two bays in Hiva Oa Island only 1 km apart, have different responses depending on the tsunami, as it was observed in 1946 (Aleutian earthquake) and 1960 (Chile earthquake). For this reason, we study the azimuthal dependence of the excitation of the free oscillation modes, and we show that some azimuths enhance tsunami amplification.

  3. Microtextural analysis of quartz grains of tsunami and non-tsunami deposits - A case study from Tirúa (Chile)

    NASA Astrophysics Data System (ADS)

    Bellanova, Piero; Bahlburg, Heinrich; Nentwig, Vanessa; Spiske, Michaela

    2016-08-01

    In order to estimate the tsunami hazard it is essential to reliably identify and differentiate tsunami deposits from other high-energy events like storms. Recently, the microtextural analysis of quartz grain surfaces was introduced as a method to differentiate between tsunami and other deposits. Using tsunami deposits sampled from a bank profile of the Tirúa river (central Chile), an area that was significantly affected by the 2010 and 1960 Chile tsunamis, we tested the microtextural analysis method for its capability to identify tsunami deposits. A total of 815 quartz grain surfaces of two tsunami layers, two non-tsunami marsh sediment samples, and three reference samples from nearby beach, dune and river were analyzed using scanning electron microscopy (SEM). We grouped the detected microtexture features into five microtextural families: angularity, fresh surfaces, percussion marks, adhering particles and dissolution features. Both the tsunami deposits and reference samples reveal high numbers of fresh surfaces and percussion marks. Thus, there are no statistically significant differences between tsunami, beach, dune and river deposits in characteristics and abundances in all microtextural families. Our study indicates that the microtextural analysis of quartz grains may not be a suitable method to identify tsunami deposits in Tirúa (Chile), due to local factors such as high numbers of inherited microtextures and the possible effects of the high amount of heavy minerals.

  4. Sheltered coastal environments as archives of paleo-tsunami deposits: Observations from the 2004 Indian Ocean tsunami

    NASA Astrophysics Data System (ADS)

    Andrade, Vanessa; Rajendran, Kusala; Rajendran, C. P.

    2014-12-01

    The 2004 earthquake left several traces of coseismic land deformation and tsunami deposits, both on the islands along the plate boundary and distant shores of the Indian Ocean rim countries. Researchers are now exploring these sites to develop a chronology of past events. Where the coastal regions are also inundated by storm surges, there is an additional challenge to discriminate between the deposits formed by these two processes. Paleo-tsunami research relies largely on finding deposits where preservation potential is high and storm surge origin can be excluded. During the past decade of our work along the Andaman and Nicobar Islands and the east coast of India, we have observed that the 2004 tsunami deposits are best preserved in lagoons, inland streams and also on elevated terraces. Chronological evidence for older events obtained from such sites is better correlated with those from Thailand, Sri Lanka and Indonesia, reiterating their usefulness in tsunami geology studies.

  5. 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

  6. Preliminary evidence for a 1000-year-old tsunami in the South China Sea

    PubMed Central

    Sun, Liguang; Zhou, Xin; Huang, Wen; Liu, Xiaodong; Yan, Hong; Xie, Zhouqing; Wu, Zijun; Zhao, Sanping; Da Shao; Yang, Wenqing

    2013-01-01

    The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area. PMID:23575432

  7. Preliminary evidence for a 1000-year-old tsunami in the South China Sea.

    PubMed

    Sun, Liguang; Zhou, Xin; Huang, Wen; Liu, Xiaodong; Yan, Hong; Xie, Zhouqing; Wu, Zijun; Zhao, Sanping; Da Shao; Yang, Wenqing

    2013-01-01

    The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area.

  8. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  9. Observed and modeled tsunami current velocities in Humboldt Bay and Crescent City Harbor, northern California

    NASA Astrophysics Data System (ADS)

    Admire, A. R.; Dengler, L.; Crawford, G. B.; uslu, B. U.; Montoya, J.

    2012-12-01

    A pilot project was initiated in 2009 in Humboldt Bay, about 370 kilometers (km) north of San Francisco, California, to measure the currents produced by tsunamis. Northern California is susceptible to both near- and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 km north of Humboldt Bay, suffered US 20 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US 20 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600kHz 2D Acoustic Doppler Current Profiler (ADCP) with a one-minute sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the Mw 8.8 Chile earthquake on February 27, 2010 and the Mw 9.0 Japan earthquake on March 11, 2011. Currents from the 2010 tsunami persisted in Humboldt Bay for at least 30 hours with peak amplitudes of about 0.3 meters per second (m/s). The 2011 tsunami signal lasted for over 86 hours with peak amplitude of 0.95 m/s. Strongest currents corresponded to the maximum change in water level as recorded on the NOAA NOS tide gauge, and occurred 90 minutes after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and a half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master building across from the entrance to the small boat basin, approximately 70 meters away from the NOAA NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities both in Humboldt Bay and in

  10. A~probabilistic tsunami hazard assessment for Indonesia

    NASA Astrophysics Data System (ADS)

    Horspool, N.; Pranantyo, I.; Griffin, J.; Latief, H.; Natawidjaja, D. H.; Kongko, W.; Cipta, A.; Bustaman, B.; Anugrah, S. D.; Thio, H. K.

    2014-05-01

    Probabilistic hazard assessments are a fundamental tool for assessing the threats posed by hazards to communities and are important for underpinning evidence based decision making on risk mitigation activities. Indonesia has been the focus of intense tsunami risk mitigation efforts following the 2004 Indian Ocean Tsunami, but this has been largely concentrated on the Sunda Arc, with little attention to other tsunami prone areas of the country such as eastern Indonesia. We present the first nationally consistent Probabilistic Tsunami Hazard Assessment (PTHA) for Indonesia. This assessment produces time independent forecasts of tsunami hazard at the coast from tsunami generated by local, regional and distant earthquake sources. The methodology is based on the established monte-carlo approach to probabilistic seismic hazard assessment (PSHA) and has been adapted to tsunami. We account for sources of epistemic and aleatory uncertainty in the analysis through the use of logic trees and through sampling probability density functions. For short return periods (100 years) the highest tsunami hazard is the west coast of Sumatra, south coast of Java and the north coast of Papua. For longer return periods (500-2500 years), the tsunami hazard is highest along the Sunda Arc, reflecting larger maximum magnitudes along the Sunda Arc. The annual probability of experiencing a tsunami with a height at the coast of > 0.5 m is greater than 10% for Sumatra, Java, the Sunda Islands (Bali, Lombok, Flores, Sumba) and north Papua. The annual probability of experiencing a tsunami with a height of >3.0 m, which would cause significant inundation and fatalities, is 1-10% in Sumatra, Java, Bali, Lombok and north Papua, and 0.1-1% for north Sulawesi, Seram and Flores. The results of this national scale hazard assessment provide evidence for disaster managers to prioritise regions for risk mitigation activities and/or more detailed hazard or risk assessment.

  11. Study of resonant modes of the harbour of Siracusa, Italy, and of the effects of breakwaters in case of a tsunami event.

    NASA Astrophysics Data System (ADS)

    Pagnoni, Gianluca; Tinti, Stefano

    2016-04-01

    The eastern coast of Sicily has been hit by many historical tsunamis of local and remote origin. This zone and in particular Siracusa, as test site, was selected in the FP7 European project ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839). According to the project goals, in this work oscillations modes of the Siracusa harbour were analysed with focus on the typical tsunami periods range, and on the protecting effects of breakwaters by using linear and non-linear simulation models. The city of Siracusa is located north of the homonymous gulf and has two harbours, called "Piccolo" (small) and "Grande" (grand) that are connected through a narrow channel. The harbour "Piccolo" is the object of this work. It is located at the end of a bay facing east and bordered on the south by the peninsula of Ortigia and on the north by the mainland. The basin has an area of approximately 100,000 m2 and is very shallow with an average depth of 2.5 m. It is protected by two breakwaters reducing its mouth to only 40 m width. This study was carried out using the numerical code UBO-TSUFD that solves linear and non-linear shallow-water equations on a high-resolution 2m x 2m regular grid. Resonant modes were searched by sinusoidal forcing on the open boundary with periods in a range from about 60 s to 1600 s covering the typical tsunami spectrum. The work was divided into three phases. First we studied the natural resonance frequencies, and in particular the Helmholtz resonance mode by using a linear fixed-geometry model and assuming that the connecting channel between the two Siracusa ports is closed. Second, we repeated the analysis by using a non-linear simulation model accounting for flooding and for an open connection channel. Eventually, we forced the harbour by means of synthetic signals with amplitude, period and duration of the main historical tsunamis attacking Siracusa, namely the AD 365, the 1693 and the 1908 tsunami

  12. Post Tsunami Survey along the Myanmar Coast due to the December 2004 Sumatra-Andaman Earthquake

    NASA Astrophysics Data System (ADS)

    Aung, T.; Satake, K.; Okamura, Y.; Sawai, Y.; Win, K. S.; Swe, W.; Swe, C.; Swe, T. L.; Tun, S. T.; Soe, M. M.; Oo, T. Z.; Zaw, S. H.

    2005-12-01

    Post tsunami survey along the Myanmar coast indicates that the maximum tsunami heights from the 2004 Sumatra-Andaman earthquake were less than 3 m and the damage was limited with total number of casualties of 61. Our interviews indicate that nobody felt the earthquake ground shaking around the origin time (07:28 in Myanmar local time). Measurements of tsunami heights, on the basis of eyewitness accounts, debris line and water marker, were made at 22 sites in Ayeyarwaddy Delta and the Taninthayi coast. In Ayeyarwaddy Delta, six measurements indicate that the tsunami heights were between 0.6 and 2.3 m above the sea level at the time of tsunami arrival, which is reported as between 11:00 and 11:45. The casualties were reported as 25 around the delta. Around Dawei, seven measurements indicate the tsunami heights between 0.9 and 2.9 m and arrival times between 10:00 and 14:00. Two measurements around Myeik show that the heights were 0.7 and 2.2 m and the arrival times were 11:00 and 12:00. Around Kawthaung near Thai boarder, seven measurements show the heights between 0.4 and 2.6 m, and the arrival times between 10:30 and 11:45. Much smaller tsunami heights than the neighboring Thai coast, where the tsunami heights were between 5 to 20 m with casualties about 8300, explain relatively less tsunami damage in Myanmar. The reason for the smaller tsunami was probably due to the fact the tsunami source did not extend to Andaman Islands. The tsunami travel times and maximum heights computed from a 700 km long source are basically consistent with the observation. For a nearby tsunami source, the tsunami hazard would be more significant in Myanmar, because coastal houses are unprotected for tsunamis and no infrastructure exists to disseminate tsunami warning information.

  13. New study on the 1941 Gloria Fault earthquake and tsunami

    NASA Astrophysics Data System (ADS)

    Baptista, Maria Ana; Miranda, Jorge Miguel; Batlló, Josep; Lisboa, Filipe; Luis, Joaquim; Maciá, Ramon

    2016-08-01

    The M ˜ 8.3-8.4 25 November 1941 was one of the largest submarine strike-slip earthquakes ever recorded in the Northeast (NE) Atlantic basin. This event occurred along the Eurasia-Nubia plate boundary between the Azores and the Strait of Gibraltar. After the earthquake, the tide stations in the NE Atlantic recorded a small tsunami with maximum amplitudes of 40 cm peak to through in the Azores and Madeira islands. In this study, we present a re-evaluation of the earthquake epicentre location using seismological data not included in previous studies. We invert the tsunami travel times to obtain a preliminary tsunami source location using the backward ray tracing (BRT) technique. We invert the tsunami waveforms to infer the initial sea surface displacement using empirical Green's functions, without prior assumptions about the geometry of the source. The results of the BRT simulation locate the tsunami source quite close to the new epicentre. This fact suggests that the co-seismic deformation of the earthquake induced the tsunami. The waveform inversion of tsunami data favours the conclusion that the earthquake ruptured an approximately 160 km segment of the plate boundary, in the eastern section of the Gloria Fault between -20.249 and -18.630° E. The results presented here contribute to the evaluation of tsunami hazard in the Northeast Atlantic basin.

  14. The "SABEIS" Project: Warning systems based on earthquake and tsunamis-induced ionospheric effects.

    NASA Astrophysics Data System (ADS)

    Rodriguez-Bouza, Marta; Sánchez-Dulcet, Francisco; Herraiz, Miguel; Rodríguez-Caderot, Gracia; Altadill, David; Blanch, Estefania; Santoyo, Miguel Angel

    2016-04-01

    The study of a possible lithosphere-atmosphere-ionosphere coupling (LAI) is mainly focused on the analysis and comprehension of atmospheric and ionospheric anomalies caused by extreme lithospheric events. In this context, earthquakes are considered as possible sources of atmosphere-ionosphere anomalies. The goal of the two-year long project SABEIS (Sistemas de Alerta Basados en Efectos de terremotos y tsunamis en la IonoSfera) granted by the Spanish Ministry of Economy and Competitiveness, is to analyze the disturbances caused by earthquakes and tsunamis and their possible contribution to warning systems. These topics are receiving increased attention in the scientific community and their correct understanding can meaningfully contribute to the protection of people and economic assets in areas subject to seismic threat. The project is based on the analysis of Total Electron Content (TEC) obtained from signals of Global Navigation Satellite Systems (GNSS) and anomalies of the ionospheric F2 layer observed in ionograms. This methodology was partially applied in a previous study of the Mw6.1 earthquake in Greece occurred on January 26, 2014. In that case two TEC disturbances were detected the days prior the earthquake. The first one, four days before, was registered by the majority of the stations analyzed over Europe and after studying its temporal variation, was considered unrelated to the earthquake. The second one occurred the day before the earthquake. This anomaly appeared only at stations close to the epicenter and their temporal proximity to the earthquake point to a possible connection with the earthquake preparation process. In the SABEIS project possible anomalies caused by earthquakes in Mexico and Peru with magnitude ranging from 5.5 to 8.2, will be studied. If the results confirm the influence of seismic events on the ionosphere, the possibility of incorporating this type of analysis in a seismic alert network for the Gulf of Cadiz (southern Iberian

  15. Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.

    2000-01-01

    Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved. Shallow water (<25 m) around Augustine Island, in the run-out zone for debris avalanches, limits the size of an avalanche-caused wave. If the two most recent debris avalanches, Burr Point (A.D. 1883) and West Island (<500 yr. B.P.) were traveling at velocities in the range of 50 to 100 meters per second, the kinetic energy of the avalanches at the point of impact with the ocean would have been between 1014 and 1015 joules. Although some of this energy would be dissipated through boundary interactions and momentum transfer between the avalanche and the sea, the initial wave should have possessed sufficient kinetic energy to do geomorphic work (erosion, sediment transport, formation of wave-cut features) on the coastline of lowwer Cook Inlet. Because widespread evidence of the effects of large waves cannot be found, it appears that the debris avalanches could not have been traveling very fast when they entered the sea, or they happened during low tide and displaced only small volumes of water. In light of these results, the hazard from volcanigenic tsunamis from Augustine Volcano appears minor, unless a very large debris avalanche occurs at high tide.

  16. Marin Tsunami (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. The Marin coast could be struck by a tsunami. Whether you live in Marin County, visit the beaches, or rent or own a home near the coast, it is vital to understand the tsunami threat and take preparation seriously. Marin Tsunami tells the story of what several West Marin communities are doing to be prepared. This video was produced by the US Geological Survey (USGS) in cooperation with the Marin Office of Emergency Services.

  17. Development of an online tool for tsunami inundation simulation and tsunami loss estimation

    NASA Astrophysics Data System (ADS)

    Srivihok, P.; Honda, K.; Ruangrassamee, A.; Muangsin, V.; Naparat, P.; Foytong, P.; Promdumrong, N.; Aphimaeteethomrong, P.; Intavee, A.; Layug, J. E.; Kosin, T.

    2014-05-01

    The devastating impacts of the 2004 Indian Ocean tsunami highlighted the need for an effective end-to-end tsunami early warning system in the region that connects the scientific components of warning with preparedness of institutions and communities to respond to an emergency. Essential to preparedness planning is knowledge of tsunami risks. In this study, development of an online tool named “INSPIRE” for tsunami inundation simulation and tsunami loss estimation is presented. The tool is designed to accommodate various accuracy levels of tsunami exposure data which will support the users to undertake preliminary tsunami risk assessment from the existing data with progressive improvement with the use of more detailed and accurate datasets. Sampling survey technique is introduced to improve the local vulnerability data with lower cost and manpower. The performance of the proposed methodology and the INSPIRE tool were tested against the dataset in Kamala and Patong municipalities, Phuket province, Thailand. The estimated building type ratios from the sampling survey show the satisfactory agreement with the actual building data at the test sites. Sub-area classification by land use can improve the accuracy of the building type ratio estimation. For the resulting loss estimation, the exposure data generated from detailed field survey can provide the agreeable results when comparing to the actual building damage recorded for the Indian Ocean tsunami event in 2004. However, lower accuracy exposure data derived from sampling survey and remote sensing can still provide a comparative overview of estimated loss.

  18. Estimating tsunami inundation from hurricane storm surge predictions along the U.S. gulf coast

    NASA Astrophysics Data System (ADS)

    Pampell-Manis, Alyssa; Horrillo, Juan; Figlus, Jens

    2016-08-01

    Gulf of Mexico (GOM) coasts have been included in the U.S. Tsunami Warning System since 2005. While the tsunami risk for the GOM is low, tsunamis generated by local submarine landslides pose the greatest potential threat, as evidenced by several large ancient submarine mass failures identified in the northern GOM basin. Given the lack of significant historical tsunami evidence in the GOM, the potential threat of landslide tsunamis in this region is assessed from a worst-case scenario perspective based on a set of events including the large ancient failures and most likely extreme events determined by a probabilistic approach. Since tsunamis are not well-understood along the Gulf Coast, we investigate tsunami inundation referenced to category-specific hurricane storm surge levels, which are relatively well established along the Gulf Coast, in order to provide information for assessing the potential threat of tsunamis which is more understandable and accessible to emergency managers. Based on tsunami inundation studies prepared for the communities of South Padre Island, TX, Galveston, TX, Mobile, AL, Panama City, FL, and Tampa, FL, we identify regional trends of tsunami inundation in terms of modeled storm surge inundation. The general trends indicate that tsunami inundation can well exceed the level of storm surge from major hurricanes in open beachfront and barrier island regions, while more interior areas are less threatened. Such information can be used to better prepare for tsunami events as well as provide a preliminary estimate of tsunami hazard in locations where detailed tsunami inundation studies have not been completed.

  19. Dispersion of tsunamis: does it really matter?

    NASA Astrophysics Data System (ADS)

    Glimsdal, S.; Pedersen, G. K.; Harbitz, C. B.; Løvholt, F.

    2013-06-01

    This article focuses on the effect of dispersion in the field of tsunami modeling. Frequency dispersion in the linear long-wave limit is first briefly discussed from a theoretical point of view. A single parameter, denoted as "dispersion time", for the integrated effect of frequency dispersion is identified. This parameter depends on the wavelength, the water depth during propagation, and the propagation distance or time. Also the role of long-time asymptotes is discussed in this context. The wave generation by the two main tsunami sources, namely earthquakes and landslides, are briefly discussed with formulas for the surface response to the bottom sources. Dispersive effects are then exemplified through a semi-idealized study of a moderate-strength inverse thrust fault. Emphasis is put on the directivity, the role of the "dispersion time", the significance of the Boussinesq model employed (dispersive effect), and the effects of the transfer from bottom sources to initial surface elevation. Finally, the experience from a series of case studies, including earthquake- and landslide-generated tsunamis, is presented. The examples are taken from both historical (e.g. the 2011 Japan tsunami and the 2004 Indian Ocean tsunami) and potential tsunamis (e.g. the tsunami after the potential La Palma volcanic flank collapse). Attention is mainly given to the role of dispersion during propagation in the deep ocean and the way the accumulation of this effect relates to the "dispersion time". It turns out that this parameter is useful as a first indication as to when frequency dispersion is important, even though ambiguity with respect to the definition of the wavelength may be a problem for complex cases. Tsunamis from most landslides and moderate earthquakes tend to display dispersive behavior, at least in some directions. On the other hand, for the mega events of the last decade dispersion during deep water propagation is mostly noticeable for transoceanic propagation.

  20. Volcanic Tsunami Generation in the Aleutian Arc of Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Watts, P.

    2003-12-01

    , geological evidence of tsunamis, such as tsunami deposits on land, should be found in the area around Augustine Island. Paradoxically, unequivocal evidence for tsunami inundation has been found. Augustine Volcano is the most historically active volcano in the Cook Inlet region and a future tsunami from the volcano would have devastating consequences to villages, towns, oil-production facilities, and the fishing industry, especially if it occurred at high tide (the tidal range in this area is about 5 m). Numerical simulation experiments of tsunami generation, propagation and inundation using a subaerial debris avalanche source at Augustine volcano indicate only modest wave generation because of the shallow water surrounding the volcano (maximum water depth about 25 m). Lahar flows produced during eruptions at snow and ice clad volcanoes in the Aleutian arc also deliver copious amounts of sediment to the sea. These flows only rarely transform to subaqueous debris flows that may become tsunamigenic. However, the accumulation of loose, unconsolidated sediment on the continental shelf may lead to subaqueous debris flows and landslides if these deposits become mobilized by large earthquakes. Tsunamis produced by this mechanism could potentially reach coastlines all along the Pacific Rim. Finally, recent work in the western Aleutian Islands indicates that many of the island volcanoes in this area have experienced large-scale flank collapse. Because these volcanoes are surrounded by deep water, the tsunami hazard associated with a future sector collapse could be significant.

  1. Tsunami Generation and Propagation by 3D deformable Landslides and Application to Scenarios

    NASA Astrophysics Data System (ADS)

    McFall, Brian C.; Fritz, Hermann M.

    2014-05-01

    Tsunamis generated by landslides and volcano flank collapse account for some of the most catastrophic natural disasters recorded and can be particularly devastative in the near field region due to locally high wave amplitudes and runup. The events of 1958 Lituya Bay, 1963 Vajont reservoir, 1980 Spirit Lake, 2002 Stromboli and 2010 Haiti demonstrate the danger of tsunamis generated by landslides or volcano flank collapses. Unfortunately critical field data from these events is lacking. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by means of four pneumatic pistons down a 2H:1V slope. The landslide is launched from the sliding box and continues to accelerate by gravitational forces up to velocities of 5 m/s. The landslide Froude number at impact with the water is in the range 1 effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified

  2. The Chile tsunami of 27 February 2010: Field survey and modeling

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Petroff, C. M.; Catalan, P. A.; Cienfuegos, R.; Winckler, P.; Kalligeris, N.; Weiss, R.; Meneses, G.; Valderas-Bermejo, C.; Barrientos, S. E.; Ebeling, C. W.; Papadopoulos, A.; Contreras, M.; Almar, R.; Dominguez, J.; Synolakis, C.

    2011-12-01

    On 27 February, 2010 a magnitude Mw 8.8 earthquake occurred off the coast of Chile's Maule region some 100 km N of Concepción, causing substantial damage and loss of life on Chile's mainland and the Juan Fernandez archipelago. The majority of the 521 fatalities are attributed to the earthquake, while the tsunami accounts for 124 victims. Fortunately, ancestral knowledge from past tsunamis such as the giant 1960 event, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. The majority of the tsunami victims were tourists staying overnight in low lying camp grounds along the coast. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 3 to 25 March ITST covered an 800 km stretch of coastline from Quintero to Mehuín in various subgroups the Pacific Islands of Santa María, Juan Fernández Archipelago, and Rapa Nui (Easter), while Mocha Island was surveyed 21 to 23 May, 2010. The collected survey data includes more than 400 tsunami runup and flow depth measurements. The tsunami impact peaked with a localized maximum runup of 29 m on a coastal bluff at Constitución and 23 m on marine terraces on Mocha Island. A significant variation in tsunami impact was observed along Chile's mainland both at local and regional scales. Inundation and damage also occurred several kilometres inland along rivers. Eyewitness tsunami videos are analysed and flooding velocities presented. Observations from the Chile tsunami are compared against the 1960 Chile, 2004 Indian Ocean and 2011 Tohoku Japan tsunamis. The tsunamigenic seafloor displacements were partially characterized based on coastal uplift measurements along a 100 km stretch of coastline

  3. Deep Ocean Tsunami Waves off the Sri Lankan Coast

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The initial tsunami waves resulting from the undersea earthquake that occurred at 00:58:53 UTC (Coordinated Universal Time) on December 26, 2004, off the island of Sumatra, Indonesia, took a little over 2 hours to reach the teardrop-shaped island of Sri Lanka. Additional waves continued to arrive for many hours afterward. At approximately 05:15 UTC, as NASA's Terra satellite passed overhead, the Multi-angle Imaging SpectroRadiometer (MISR) captured this image of deep ocean tsunami waves about 30-40 kilometers from Sri Lanka's southwestern coast. The waves are made visible due to the effects of changes in sea-surface slope on the reflected sunglint pattern, shown here in MISR's 46-degree-forward-pointing camera. Sunglint occurs when sunlight reflects off a water surface in much the same way light reflects off a mirror, and the position of the Sun, angle of observation, and orientation of the sea surface determines how bright each part of the ocean appears in the image. These large wave features were invisible to MISR's nadir (vertical-viewing) camera. The image covers an area of 208 kilometers by 207 kilometers. The greatest impact of the tsunami was generally in an east-west direction, so the havoc caused by the tsunami along the southwestern shores of Sri Lanka was not as severe as along the eastern coast. However, substantial damage did occur in this region' as evidenced by the brownish debris in the water' because tsunami waves can diffract around land masses. The ripple-like wave pattern evident in this MISR image roughly correlates with the undersea boundary of the continental shelf. The surface wave pattern is likely to have been caused by interaction of deep waves with the ocean floor, rather than by the more usually observed surface waves, which are driven by winds. It is possible that this semi-concentric pattern represents wave reflection from the continental land mass; however, a combination of wave modeling and detailed bathymetric data is required to

  4. Source estimate and tsunami forecast from far-field deep-ocean tsunami waveforms—The 27 February 2010 Mw 8.8 Maule earthquake

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Masahiro; Watada, Shingo; Fujii, Yushiro; Satake, Kenji

    2016-01-01

    We inverted the 2010 Maule earthquake tsunami waveforms recorded at DART (Deep-ocean Assessment and Reporting Tsunamis) stations in the Pacific Ocean by taking into account the effects of the seawater compressibility, elasticity of the solid Earth, and gravitational potential change. These effects slow down the tsunami speed and consequently move the slip offshore or updip direction, consistent with the slip distribution obtained by a joint inversion of DART, tide gauge, GPS, and coastal geodetic data. Separate inversions of only near-field DART data and only far-field DART data produce similar slip distributions. The former demonstrates that accurate tsunami arrival times and waveforms of trans-Pacific tsunamis can be forecast in real time. The latter indicates that if the tsunami source area is as large as the 2010 Maule earthquake, the tsunami source can be accurately estimated from the far-field deep-ocean tsunami records without near-field data.

  5. 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

  6. 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.

  7. The 1768 and 1791 Okinawa tsunamis in the Ryukyu Trench region

    NASA Astrophysics Data System (ADS)

    Nakamura, M.

    2013-12-01

    Risk of the great earthquakes and tsunamis has been assumed to be low in the Ryukyu Trench because the interplate coupling is weak and great interplate earthquakes (> M8.0) had not been recorded historically for about 300 years. However, recent study revealed that the 1771 Yaeyama earthquake (M8.5 from tsunami heights distribution) at south Ryukyu Trench and the 1911 Kikaijima earthquake (M 8.0) at north-central Ryukyu Trench were the interplate earthquakes. We need re-examine the great historical earthquakes in the Ryukyu Trench. Two historical tsunamis which occurred on 1768 and 1791 in the Okinawa Island were documented in the old document 'Kyuyo' (formal chronicles of Ryukyu). I investigated the source fault model of two tsunami events using numerical simulations of tsunami and earthquake shaking, and showed that their events would be the interplate earthquakes. One earthquake occurred at noon of July 22th, 1768. The rock-walls of castle, grave of royal family were collapsed by the earthquake shaking around Naha, Okinawa Island. After the shaking, tsunami arrived Naha port and Zamami Island, which is west of Okinawa Island. Recorded tsunami heights were about 1 m at Naha port. Nine houses and rice fields were damaged by the inundation of the tsunami in the Zamami Island. Estimated tsunami heights were 4 and 5 m in the villages of the Zamami Island. The numerical modeling of tsunami and the estimation of earthquake shaking using empirical formula were employed, and the fault parameters of the 1768 earthquake were estimated. The faults were set to Okinawa Trough (M7.5 normal faults), southwest of Okinawa island (M7.5 normal faults), southwest of Okinawa island (M7.5 reverse fault), and Ryukyu Trench (M8.0 thrust faults). The computed tsunami heights and intensities of the ground shaking of the M7.5 reverse fault near the Zamami Island and the M8.0 interplate earthquake models are consistent with to the recorded ones. Another tsunami was also recorded in the

  8. 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.

  9. Resonance interaction between Bays and Harbors forced by tsunamis

    NASA Astrophysics Data System (ADS)

    Vela, Jordi; Pérez, Begoña.; González, Mauricio; Otero, Luis; Olabarrieta, Maitane; Canals, Miquel

    2010-05-01

    The tsunami induced by the 21 May 2003 Boumerdès-Zemmouri (Algeria) earthquake (Mw=6.9) did not generated important inundations damages or fatalities in the western Mediterranean area. However, damages and economic losses were reported in some harbors, generated by important sea level disturbances. Noticeable impacts were noted (broken mooring lines, sunken boats, displaced moorings, etc.) in some harbours in the Balearic Islands (Palma de Majorca, Ibiza and San Antoni) and also along the French border (La Figueirette and Mouré-Rouge harbours). Various authors have attempted to simulate this event finding discrepancies between the tsunami arrival time and amplitudes of waves on the tide gauges and results with numerical models. The models underestimate the amplitude of the tsunami. In some cases the underestimations have been associated to numerical limitations due to the lack of a high-resolution bathymetry and poor harbor geometry definition. Other cases, associated to a non appropriate seismic source characterization. Finally, some authors point out the occurrence of one or several submarine landslides triggered by the earthquake simultaneously with the seafloor vertical displacement, which have not been included in the numerical simulations. For a better knowledge of the response of a harbour interacting with a bay forced by a tsunami, a numerical study has been carried out for Palma Bay and Palma de Majorca Harbour. The transference of energy of the tsunami from the generation area to the continental shelf, the bay and the harbour has been studied for the Algerian tsunami (21 May 2003) and compared with the natural oscillation modes of the bay and the harbour water bodies. Furthermore, a sensibility analysis regarding the influence of the grid size of the harbour and bay bathymetries was also performed to understand the discrepancies between simulations and observations. The 2003 Zemmouri tsunami measured by the tidal gauge of Palma habour showed energy

  10. 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; 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.

  11. How soon is too soon? When to cancel a warning after a damaging tsunami

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Following an earthquake a tsunami warning center (TWC) must determine if a coastal evacuation is necessary and must do so fast enough for the warning to be useful to affected coastlines. Once a damaging tsunami has arrived, the TWC must decide when to cancel its warning, a task often more challenging than the initial hazard assessment. Here we demonstrate the difficulties by investigating the impact of the Tohoku tsunami of 11 March 2011 on the State of Hawaii, which relies on the Pacific Tsunami Warning Center (PTWC) for tsunami hazard guidance. PTWC issued a Tsunami Watch for Hawaii at 10 March 1956 HST (10 minutes after the earthquake) and upgraded to a Tsunami Warning at 2131 HST. The tsunami arrived in Hawaii just before 0300 HST the next day, reached a maximum runup of over 5 m, and did roughly $50 million in damage throughout the state. PTWC downgraded the Warning to an Advisory at 0730 HST, and canceled the Advisory at 1140 HST. The timing of the downgrade was appropriate—by then it was safe for coastal residents to re-enter the evacuation zone but not to enter the water—but in retrospect PTWC cancelled its Advisory too early. By late morning tide gauges throughout the state had all registered maximum wave heights of 30 cm or less for a couple of hours, so PTWC cancelled. The Center was unaware, however, of ocean behavior at locations without instruments. At Ma'alaea Harbor on the Island of Maui, for example, sea level oscillations exposed the harbor bottom every 20 minutes for several hours after the cancellation. At Waikiki on Oahu, lifeguards rescued 25 swimmers (who had either ignored or were unaware of the cancellation message's caution about hazardous currents) in the hours after the cancellation and performed CPR on one near-drowning victim. Fortunately, there were no deaths. Because of dangerous surges, ocean safety officials closed Hanauma Bay, a popular snorkeling spot on Oahu, for a full day after the tsunami hit. They reassessed the bay the

  12. Magnitude-based scaling of tsunami propagation

    NASA Astrophysics Data System (ADS)

    Simanjuntak, M. Arthur; Greenslade, Diana J. M.

    2011-07-01

    Most current operational tsunami prediction systems are based upon databases of precomputed tsunami scenarios, where some form of linear scaling is applied to the precomputed model runs in order to represent specific earthquake magnitudes. This can introduce errors due to assumptions made about the rupture width and possible effects on dispersion. In this paper, we perform a series of numerical experiments on uniform depth domains, using the Method of Splitting Tsunamis (MOST) model, and develop estimates of the maximum error that an assumed discrepancy in the width of a rupture will produce in the resulting field of maximum tsunami amplitude. This estimate was produced from fitting the decay of maximum amplitude with normalized distance for various resolutions of the source widths to the grid size, resulting in a simple power law whose coefficients effectively vary with wavelength resolution. This provides a quantification of the effect that linear scaling of precomputed scenarios will have on forecasts of tsunami amplitude. This estimate of scaling bias is investigated in relation to the scenario database that is currently in use within the Joint Australian Tsunami Warning Centre.

  13. Tsunami: Sri Lanka

    Atmospheric Science Data Center

    2013-04-16

    article title:  Deep Ocean Tsunami Waves off the Sri Lankan Coast     ... Imaging SpectroRadiometer (MISR) captured this image of deep ocean tsunami waves about 30-40 kilometers from Sri Lanka's southwestern coast. ... to be caused by interaction of deep waves with the ocean floor, rather than by the more usually-observed surface waves driven by winds. ...

  14. Tsunami warnings: Understanding in Hawai'i

    USGS Publications Warehouse

    Gregg, Chris E.; Houghton, B.F.; Paton, Douglas; Johnston, David M.; Swanson, D.A.; Yanagi, B.S.

    2007-01-01

    The devastating southeast Asian tsunami of December 26, 2004 has brought home the destructive consequences of coastal hazards in an absence of effective warning systems. Since the 1946 tsunami that destroyed much of Hilo, Hawai'i, a network of pole mounted sirens has been used to provide an early public alert of future tsunamis. However, studies in the 1960s showed that understanding of the meaning of siren soundings was very low and that ambiguity in understanding had contributed to fatalities in the 1960 tsunami that again destroyed much of Hilo. The Hawaiian public has since been exposed to monthly tests of the sirens for more than 25 years and descriptions of the system have been widely published in telephone books for at least 45 years. However, currently there remains some uncertainty in the level of public understanding of the sirens and their implications for behavioral response. Here, we show from recent surveys of Hawai'i residents that awareness of the siren tests and test frequency is high, but these factors do not equate with increased understanding of the meaning of the siren, which remains disturbingly low (13%). Furthermore, the length of time people have lived in Hawai'i is not correlated systematically with understanding of the meaning of the sirens. An additional issue is that warning times for tsunamis gene rated locally in Hawai'i will be of the order of minutes to tens of minutes and limit the immediate utility of the sirens. Natural warning signs of such tsunamis may provide the earliest warning to residents. Analysis of a survey subgroup from Hilo suggests that awareness of natural signs is only moderate, and a majority may expect notification via alerts provided by official sources. We conclude that a major change is needed in tsunami education, even in Hawai'i, to increase public understanding of, and effective response to, both future official alerts and natural warning signs of future tsunamis. ?? Springer 2006.

  15. Using Inundation and Sediment Transport Modeling To Characterize Earthquake Source Parameters from Tsunami Deposits

    NASA Astrophysics Data System (ADS)

    Gelfenbaum, G. R.; La Selle, S.; Witter, R. C.; Sugawara, D.; Jaffe, B. E.

    2015-12-01

    Inferring the relative magnitude of tsunamis generated during earthquakes based on the characteristics of sandy coastal deposits is a challenging problem. Using a hydrodynamic and sediment transport model, we explore whether the volume of sandy tsunami deposits can be used to infer tsunami magnitude and seafloor deformation. For large subduction zone earthquakes specifically, we are testing the hypothesis that onshore tsunami deposit volume is correlated with nearshore tsunami wave height and coseismic slip. First, we test this hypothesis using onshore tsunami deposit volume data and offshore slip for the 2011 Tohoku earthquake and tsunami. This test considers tsunami deposit volume and offshore slip as they vary alongshore across a wide range of sediment sources, offshore and onshore slopes, and boundary roughness conditions. Preliminary analysis suggests that a strong correlation exists between onshore tsunami deposit volume and adjacent offshore coseismic slip, so long as ample sediment were available along the coast to be eroded. Second, we apply a Delft3D tsunami inundation and sediment transport model to Stardust Bay in the U.S. Aleutian Islands, where 6 tsunamis in the last ~1700 years deposited marine sand across a coastal plain as much as 800 m inland and up to ~15 m above mean sea level. The youngest sand sheet, probably deposited by a tsunami generated during the 1957 Andreanof Islands earthquake (Mw 8.6), has the smallest sediment volume. Several older deposits have larger volumes. Models show that ≥10 m of slip on the Aleutian subduction megathrust offshore of Stardust Bay could produce the onshore sediment volume measured for the 1957 deposit. Older tsunami deposits of greater volume require up to 14 m of megathrust slip. Model sensitivity studies show that onshore sediment volume is most sensitive to megathrust slip and less sensitive to other unknowns such as width of fault rupture and roughness of inundated terrain

  16. Complex earthquake rupture and local tsunamis

    USGS Publications Warehouse

    Geist, E.L.

    2002-01-01

    In contrast to far-field tsunami amplitudes that are fairly well predicted by the seismic moment of subduction zone earthquakes, there exists significant variation in the scaling of local tsunami amplitude with respect to seismic moment. From a global catalog of tsunami runup observations this variability is greatest for the most frequently occuring tsunamigenic subduction zone earthquakes in the magnitude range of 7 < Mw < 8.5. Variability in local tsunami runup scaling can be ascribed to tsunami source parameters that are independent of seismic moment: variations in the water depth in the source region, the combination of higher slip and lower shear modulus at shallow depth, and rupture complexity in the form of heterogeneous slip distribution patterns. The focus of this study is on the effect that rupture complexity has on the local tsunami wave field. A wide range of slip distribution patterns are generated using a stochastic, self-affine source model that is consistent with the falloff of far-field seismic displacement spectra at high frequencies. The synthetic slip distributions generated by the stochastic source model are discretized and the vertical displacement fields from point source elastic dislocation expressions are superimposed to compute the coseismic vertical displacement field. For shallow subduction zone earthquakes it is demonstrated that self-affine irregularities of the slip distribution result in significant variations in local tsunami amplitude. The effects of rupture complexity are less pronounced for earthquakes at greater depth or along faults with steep dip angles. For a test region along the Pacific coast of central Mexico, peak nearshore tsunami amplitude is calculated for a large number (N = 100) of synthetic slip distribution patterns, all with identical seismic moment (Mw = 8.1). Analysis of the results indicates that for earthquakes of a fixed location, geometry, and seismic moment, peak nearshore tsunami amplitude can vary by a

  17. Detiding Tsunami Currents to Validate Velocities in Numerical Simulation Codes using Observations Near Hawaii from the 2011 Tohoku Tsunami

    NASA Astrophysics Data System (ADS)

    Adams, L. M.; LeVeque, R. J.

    2015-12-01

    The ability to measure, predict, and compute tsunami flow velocities is ofimportance in risk assessment and hazard mitigation. Until recently, fewdirect measurements of tsunami velocities existed to compare with modelresults. During the 11 March 2001 Tohoku Tsunami, 328 current meters werewere in place around the Hawaiian Islands, USA, that captured time seriesof water velocity in 18 locations, in both harbors and deep channels, ata series of depths. Arcos and LeVeque[1] compared these records againstnumerical simulations performed using the GeoClaw numerical tsunami modelwhich is based on the depth-averaged shallow water equations. They confirmedthat GeoClaw can accurately predict velocities at nearshore locations, andthat tsunami current velocity is more spatially variable than wave formor height and potentially more sensitive for model validation.We present a new approach to detiding this sensitive current data. Thisapproach can be used separately on data at each depth of a current gauge.When averaged across depths, the Geoclaw results in [1] are validated. Withoutaveraging, the results should be useful to researchers wishing to validate their3D codes. These results can be downloaded from the project website below.The approach decomposes the pre-tsunami component of the data into three parts:a tidal component, a fast component (noise), and a slow component (not matchedby the harmonic analysis). Each part is extended to the time when the tsunamiis present and subtracted from the current data then to give the ''tsunami current''that can be compared with 2D or 3D codes that do not model currents in thepre-tsunami regime. [1] "Validating Velocities in the GeoClaw Tsunami Model using Observations NearHawaii from the 2001 Tohoku Tsunami"M.E.M. Arcos and Randall J. LeVequearXiv:1410.2884v1 [physics.geo-py], 10 Oct. 2014.project website: http://faculty.washington.edu/lma3/research.html

  18. Tsunami Intensity Mapping Along the Coast of Tamilnadu (India) During the Deadliest Indian Ocean Tsunami of December 26, 2004

    NASA Astrophysics Data System (ADS)

    Narayan, J. P.; Sharma, M. L.; Maheshwari, B. K.

    2006-07-01

    This paper presents tsunami intensity mapping and damage patterns along the surveyed coast of Tamilnadu (India) of the deadly Indian Ocean tsunami of December 26, 2004. The tsunami caused severe damage and claimed many victims in the coastal areas of eleven countries bordering the Indian Ocean. A twelve-stage tsunami intensity scale proposed by Papadopoulos and Imamura (2001) was followed to assign the intensity at the visited localities. Along the coast of the Indian mainland, tsunami damage sustained exclusively. Most severe damage was observed in Nagapattinam Beach, Nabiyarnagar, Vellaipalyam, and the Nagapattinam Port of Nagapattinum District on the east coast and Keelamanakudy village of Kanyakumari District on the western coast of Tamilnadu. The maximum assigned tsunami intensity was X+ at these localities. Minimum intensity V+ was received along the coast of Thanjavur, Puddukkotai and Ramnathpuram Districts in Palk Strait. The general observation reported by many people was that the first arrival was a tsunami crest. The largest tsunami waves were first arrivals on the eastern coast and the second arrivals on the western coast. Along the coast, people were unaware of the tsunami, and no anomalous behavior of ocean animals was reported. Good correlation was observed between the severity of damage and the presence of shadow zone of Sri Lanka, reflected waves from Sri Lanka and the Maldives Islands, variation in the width of the continental shelf, elevation of the coast and the presence of breakwaters. The presence of medu (naturally elevated landmass very close to the sea shore and elongated parallel to the coast) reduced the impact of the tsunami on the built environment.

  19. The 2009 South Pacific tsunami - implications for tsunami hazard in the South Pacific

    NASA Astrophysics Data System (ADS)

    Power, William; Wilson, Kate; Prasetya, Gegar; Bradley, Brendon; Wang, Xiaoming; Beavan, John; Holden, Caroline

    2010-05-01

    On 29 September 2009 a Mw8.0 earthquake at the northern end of the Tonga Trench created a tsunami with a devastating impact on the islands of Tutuila (American Samoa), Upolu (Samoa) and Niuatoputapu (Tonga). The intensity of the tsunami impact on islands close to the source was surprising for an earthquake of this magnitude, which is presumably a consequence of an unusual earthquake source. Moment tensor solutions suggest a mechanism of normal faulting in the outer-rise though this is not fully consistent with the polarity of waves observed at DART buoys within the Pacific. The written history of tsunami in the southwest Pacific is relatively short, especially for the Tonga-Kermadec-Hikurangi trench, and includes few events; consequently the question ‘How typical is this event of tsunami from this subduction zone?' is critical for understanding the tsunami hazard of the region. An important source of information on the tsunami comes from post-event surveys. Researchers from GNS Science participated in survey teams on each of the three strongly affected islands. Information collected by these surveys is very varied, and includes: estimates of physical parameters such as the distribution of run-up heights, flow depths, and inundation distances; engineering observations regarding the damage to, and relative fragility of, different types of buildings and infrastructure; observations of environmental impact and the role of the environmental factors, such as coral reefs, forests, and sand dunes, on influencing the tsunami impact; and observations of the response to the events by the local communities. This presentation will include a summary of the main findings from these surveys. The earthquake source for this event appears to have an unusual mechanism for a tsunamigenic earthquake, and to be relatively complex. Attempts to invert for the source using any one of the various collected datasets - the survey data described above, DART buoy sea level records, geodetic

  20. Tsunami Run-up Heights at Imwon Port, Korea

    NASA Astrophysics Data System (ADS)

    Cho, Yong-Sik; Cho, Jeong-Seon

    2015-04-01

    Tsunami Run-up Heights at Imwon Port, Korea Yong-Sik Cho and Jeong-Seon Cho Department of Civil and Environmental Engineering, Hanyang University 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea. The Eastern Coast of the Korean Peninsula has been attacked frequently by a number of tsunamis causing severe damages during this century. Among them, 1983 Central East Sea and 1993 Hokkaido Tsunami events were recorded as the most devastating events in Korea. More recently, the Great East Japan Tsunami had also attacked the Korean Peninsula. The Eastern Coast of the Korean Peninsula is the terminal place where tsunamis climb up inland after it generated along the western coast of Japan. The central part of the coast, in special, is worried as a tsunami danger zone because much tsunami energy is concentrated on by a topographic condition of this region. Recently, several coastal facilities including harbors and breakwaters are built and operated along the Eastern Coast of the Korean Peninsula. Furthermore, several nuclear power plants are already operating and several more units are now under construction. Residents who lived alongside the coast want free from unexpected danger, so the tsunami hazard mitigation becomes an important issue of coastal problems in Korea. Through the historical tsunami events, the Imwon Port is known as the place where most severe damage occurred, especially in 1983. An effective and economic way for the tsunami hazard mitigation planning is to construct inundation maps along the coast vulnerable to tsunami flooding. These maps should be built based on the historical tsunami events and the projected scenarios. For this purpose, an accurate estimation of tsunami run-up height and inundation process through the numerical model is needed. As a first step to tsunami mitigation program, the maximum run-up heights at the Imwon Port are computed and compared with field observed data. For this, tsunami run-up heights in this region were filed

  1. A novel new tsunami detection network using GNSS on commercial ships

    NASA Astrophysics Data System (ADS)

    Foster, J. H.; Ericksen, T.; Avery, J.

    2015-12-01

    Accurate and rapid detection and assessment of tsunamis in the open ocean is critical for predicting how they will impact distant coastlines, enabling appropriate mitigation efforts. The unexpectedly huge fault slip for the 2011 Tohoku, Japan earthquake, and the unanticipated type of slip for the 2012 event at Queen Charlotte Islands, Canada highlighted weaknesses in our understanding of earthquake and tsunami hazards, and emphasized the need for more densely-spaced observing capabilities. Crucially, when each sensor is extremely expensive to build, deploy, and maintain, only a limited network of them can be installed. Gaps in the coverage of the network as well as routine outages of instruments, limit the ability of the detection system to accurately characterize events. Ship-based geodetic GNSS has been demonstrated to be able to detect and measure the properties of tsunamis in the open ocean. Based on this approach, we have used commercial ships operating in the North Pacific to construct a pilot network of low-cost, tsunami sensors to augment the existing detection systems. Partnering with NOAA, Maersk and Matson Navigation, we have equipped 10 ships with high-accuracy GNSS systems running the Trimble RTX high-accuracy real-time positioning service. Satellite communications transmit the position data streams to our shore-side server for processing and analysis. We present preliminary analyses of this novel network, assessing the robustness of the system, the quality of the time-series and the effectiveness of various processing and filtering strategies for retrieving accurate estimates of sea surface height variations for triggering detection and characterization of tsunami in the open ocean.

  2. 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

  3. Crossing Thresholds - Human Responses to Tsunami Forcing in the Pacific

    NASA Astrophysics Data System (ADS)

    Goff, J. R.; Chague-Goff, C.

    2014-12-01

    The 11 March 2011 Tohoku-oki tsunami caused widespread devastation to coastal communities in Japan. This event however was merely the latest in a long line of similar occurrences throughout the Pacific over time. All the recent large tsunamis have had their predecessors, and a growing database of palaeotsunamis in the Pacific suggests that several past events have been either similar in magnitude or greater than their historical counterparts. Not only are we gathering data concerning Pacific palaeotsunamis but we are also identifying contemporaneous punctuated histories of changing human settlement patterns across the Pacific. In particular, the almost two millennia 'long pause' in eastward Polynesian migration and the abandonment of long distance sea-voyaging in the 15th century. It is suggested that large palaeotsunamis and their generating mechanisms forced major societal responses. Given the unquestioned impacts of recent tsunamis on human societies, it is reasonable to suggest that past societal responses can be used as proxies for contemporaneous environmental forcing in those parts of the world where independent evidence of the effects of these events is still being gathered. In the Pacific there are a range of responses that extend well beyond the abandonment of long distance sea-voyaging such as the outbreak of region-wide conflict and the associated abandonment of settlements in exposed (coastal) locations. The contemporaneity of these effects across a vast region requires a driver that is external to particular island groups. Given that this must have impacted coastal resources severely and enduringly, the only possibility is that this driver was of oceanic origin. This hypothesis is compelling when considered alongside the growing database of more conventional lines of evidence. The question therefore is how well are similar threshold responses recognised throughout the World? Are there similar region-wide responses that have been pigeonholed under the

  4. GITEWS -- The German-Indonesian Tsunami Early Warning System

    NASA Astrophysics Data System (ADS)

    Lauterjung, J.; Rudloff, A.

    2005-12-01

    The aim of this work is the implementation of an effective Tsunami Early Warning System for the Indian Ocean. It is a component part of an Early Warning System that will also be capable of registering other natural disasters such as earthquakes and volcanic eruptions. The system integrates terrestrial observation networks of seismology und geodesy with marine measurements techniques and satellite observations. The required R & D work will be realized within the framework of a stage-plan, which will, within a short time span of 1-3 years, be able to provide effective warning on the one hand and, which will also allow for an integration of technological developments, currently undergoing further research. The initiative is coordinated by the Helmholtz Association of German Research Centres (HGF), represented by the GeoForschungsZentrum Potsdam (GFZ). In view of the geological situation one has to bear in mind that Indonesia especially, due to the fact that the main islands are located next to and above the Sunda seismogenic zone, could most frequently and most intensively in the future be prone to catastrophic Tsunami events. The envisaged Early Warning System for the Indian Ocean consists of different components as broadband seismometers, GPS, tide gauges, ocean-bottom pressure sensors and GPS-Buoys. On the basis of the data and recordings registered a warning can be generated. This presentation gives insight into the creation of the 26 December 2004 Tsunami, introduces the planned technical realization of the Early Warning System, shows first model scenarios and gives an overview of the planned realization of an Early Warning System in the Indian Ocean. http://www.gfz-potsdam.de

  5. Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the U.S. East Coast and the Caribbean

    USGS Publications Warehouse

    Barkan, R.; ten Brink, U.S.; Lin, J.

    2009-01-01

    The great Lisbon earthquake of November 1st, 1755 with an estimated moment magnitude of 8.5-9.0 was the most destructive earthquake in European history. The associated tsunami run-up was reported to have reached 5-15??m along the Portuguese and Moroccan coasts and the run-up was significant at the Azores and Madeira Island. Run-up reports from a trans-oceanic tsunami were documented in the Caribbean, Brazil and Newfoundland (Canada). No reports were documented along the U.S. East Coast. Many attempts have been made to characterize the 1755 Lisbon earthquake source using geophysical surveys and modeling the near-field earthquake intensity and tsunami effects. Studying far field effects, as presented in this paper, is advantageous in establishing constraints on source location and strike orientation because trans-oceanic tsunamis are less influenced by near source bathymetry and are unaffected by triggered submarine landslides at the source. Source location, fault orientation and bathymetry are the main elements governing transatlantic tsunami propagation to sites along the U.S. East Coast, much more than distance from the source and continental shelf width. Results of our far and near-field tsunami simulations based on relative amplitude comparison limit the earthquake source area to a region located south of the Gorringe Bank in the center of the Horseshoe Plain. This is in contrast with previously suggested sources such as Marqu??s de Pombal Fault, and Gulf of C??diz Fault, which are farther east of the Horseshoe Plain. The earthquake was likely to be a thrust event on a fault striking ~ 345?? and dipping to the ENE as opposed to the suggested earthquake source of the Gorringe Bank Fault, which trends NE-SW. Gorringe Bank, the Madeira-Tore Rise (MTR), and the Azores appear to have acted as topographic scatterers for tsunami energy, shielding most of the U.S. East Coast from the 1755 Lisbon tsunami. Additional simulations to assess tsunami hazard to the U.S. East

  6. 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

  7. Far-Field Tsunami Hazard in New Zealand Ports

    NASA Astrophysics Data System (ADS)

    Borrero, Jose C.; Goring, Derek G.; Greer, S. Dougal; Power, William L.

    2015-03-01

    We present the results of a numerical modeling study investigating the effects of far-field tsunamis in New Zealand ports. Four sites (Marsden Point, Tauranga, Harbor, Port Taranaki and Lyttelton Harbor) were selected based on a combination of factors such as economic importance and the availability of historical and/or instrumental data. Numerical models were created using the ComMIT tsunami modeling tool and the Method Of Splitting Tsunami (MOST) hydrodynamic model. Comparison of model results to measured data from recent historical events showed that, for particular sites and events, the model correlated well with the timing and amplitude of the observed tsunami, and, in most cases, there was generally good agreement between the and modeled tsunami heights and current speeds. A sensitivity analysis for tsunami heights and current speeds was conducted using a suite of large ( M W 9) tsunamigenic earthquake sources situated at regular 15° intervals in azimuth along the Pacific Rim while another set of scenarios focused on regional tsunami sources in the Southwest Pacific. Model results were analyzed for tsunami heights and current speeds as a function of the source region. In terms of currents, the analysis identified where speeds were greatest and which source was responsible. Results suggested that tsunamis originating from Central America produced the strongest response in New Zealand. The modeling was also used to determine the timing and duration of potentially dangerous current speeds as well as minimum `safe depths' for vessel evacuation offshore. This study was motivated by the desire to reduce damage and operational losses via improved forecasting of far-field tsunamis at New Zealand ports. It is important that forecasts are accurate since tsunami damage to ships and facilities is expensive and can be mitigated given timely warnings and because preventable false alarms are also costly in terms of lost productivity. The modeling presented here will

  8. The 25 October 2010 Mentawai tsunami earthquake, from real-time discriminants, finite-fault rupture, and tsunami excitation

    USGS Publications Warehouse

    Newman, A.V.; Hayes, G.; Wei, Y.; Convers, J.

    2011-01-01

    The moment magnitude 7.8 earthquake that struck offshore the Mentawai islands in western Indonesia on 25 October 2010 created a locally large tsunami that caused more than 400 human causalities. We identify this earthquake as a rare slow-source tsunami earthquake based on: 1) disproportionately large tsunami waves; 2) excessive rupture duration near 125 s; 3) predominantly shallow, near-trench slip determined through finite-fault modeling; and 4) deficiencies in energy-to-moment and energy-to-duration-cubed ratios, the latter in near-real time. We detail the real-time solutions that identified the slow-nature of this event, and evaluate how regional reductions in crustal rigidity along the shallow trench as determined by reduced rupture velocity contributed to increased slip, causing the 5-9 m local tsunami runup and observed transoceanic wave heights observed 1600 km to the southeast. Copyright 2011 by the American Geophysical Union.

  9. The 25 October 2010 Mentawai tsunami earthquake, from real-time discriminants, finite-fault rupture, and tsunami excitation

    USGS Publications Warehouse

    Newman, Andrew V.; Hayes, Gavin P.; Wei, Yong; Convers, Jaime

    2011-01-01

    The moment magnitude 7.8 earthquake that struck offshore the Mentawai islands in western Indonesia on 25 October 2010 created a locally large tsunami that caused more than 400 human causalities. We identify this earthquake as a rare slow-source tsunami earthquake based on: 1) disproportionately large tsunami waves; 2) excessive rupture duration near 125 s; 3) predominantly shallow, near-trench slip determined through finite-fault modeling; and 4) deficiencies in energy-to-moment and energy-to-duration-cubed ratios, the latter in near-real time. We detail the real-time solutions that identified the slow-nature of this event, and evaluate how regional reductions in crustal rigidity along the shallow trench as determined by reduced rupture velocity contributed to increased slip, causing the 5–9 m local tsunami runup and observed transoceanic wave heights observed 1600 km to the southeast.

  10. The 25 October 2010 Mentawai tsunami earthquake, from real-time discriminants, finite-fault rupture, and tsunami excitation

    NASA Astrophysics Data System (ADS)

    Newman, Andrew V.; Hayes, Gavin; Wei, Yong; Convers, Jaime

    2011-03-01

    The moment magnitude 7.8 earthquake that struck offshore the Mentawai islands in western Indonesia on 25 October 2010 created a locally large tsunami that caused more than 400 human causalities. We identify this earthquake as a rare slow-source tsunami earthquake based on: 1) disproportionately large tsunami waves; 2) excessive rupture duration near 125 s; 3) predominantly shallow, near-trench slip determined through finite-fault modeling; and 4) deficiencies in energy-to-moment and energy-to-duration-cubed ratios, the latter in near-real time. We detail the real-time solutions that identified the slow-nature of this event, and evaluate how regional reductions in crustal rigidity along the shallow trench as determined by reduced rupture velocity contributed to increased slip, causing the 5-9 m local tsunami runup and observed transoceanic wave heights observed 1600 km to the southeast.

  11. Identifying Precursors to the 2009 South Pacific tsunami?

    NASA Astrophysics Data System (ADS)

    Goff, J. R.; Chague-Goff, C.; Etienne, S.; Lamarche, G.; Pelletier, B.; Richmond, B. M.; Strotz, L. C.; Buckley, M. L.; Wilson, K.; Dudley, W. C.; Urban, G.; Sale, M.; Dominey-Howes, D.

    2009-12-01

    The 29/30 September 2009 tsunami was a truly South Pacific event, spanning the dateline and affecting Samoa, American Samoa, Tonga, Fiji, Wallis & Futuna, and the Marquesas. Notable historical tsunamis in the region include the 1960 Chilean tsunami and a 1917 one from a source similar to the 2009 event. The historic record of large tsunamis varies between Pacific Island Countries (PICs), but it is short, rarely exceeding 200 years. It is sufficiently long however, to indicate that the tsunami hazard in the region may be high, but sufficiently short to give an extremely limited understanding of the hazard. Sadly, there are almost no South Pacific palaeotsunami data available to give a longer time and magnitude record of potential precursor events. Core and trench work in Samoa and Wallis & Futuna reveals evidence for several possible palaeotsunamis. There are up to six sand layers with associated paleosols in Samoa, and up to four in Futuna. At Tavai in Futuna, there is also an oral tradition associated with evidence of a surface boulder scatter field, and probably a sand layer overlying a past occupation site. These data are compelling and a tsunami source seems likely. This event is currently undated. On a note of caution however, sand and paleosol interbeds are common in the sandy coastal plains of tropical Pacific islands. Possible causes include cyclones and tsunamis, and it will therefore be necessary to establish diagnostic criteria to help distinguish between these different modes of formation. If these are palaeotsunamis then whether they relate to regional or distant events is also yet to be determined. Ultimately, more precise source identification will likely have to wait until a more comprehensive palaeotsunami dataset has been established for PICs. Mulivai - south coast of Samoa: Trench showing the 2009 South Pacific tsunami with at least two underlying sand unit and one palaeosol. Photo: C. Chagué-Goff

  12. Field survey of the March 28, 2005 Nias-Simeulue earthquake and Tsunami

    USGS Publications Warehouse

    Borrero, J.C.; McAdoo, B.; Jaffe, B.; Dengler, L.; Gelfenbaum, G.; Higman, B.; Hidayat, R.; Moore, A.; Kongko, W.; ,; Peters, R.; Prasetya, G.; Titov, V.; Yulianto, E.

    2011-01-01

    On the evening of March 28, 2005 at 11:09 p.m. local time (16:09 UTC), a large earthquake occurred offshore of West Sumatra, Indonesia. With a moment magnitude (Mw) of 8.6, the event caused substantial shaking damage and land level changes between Simeulue Island in the north and the Batu Islands in the south. The earthquake also generated a tsunami, which was observed throughout the source region as well as on distant tide gauges. While the tsunami was not as extreme as the tsunami of December 26th, 2004, it did cause significant flooding and damage at some locations. The spatial and temporal proximity of the two events led to a unique set of observational data from the earthquake and tsunami as well as insights relevant to tsunami hazard planning and education efforts. ?? 2010 Springer Basel AG.

  13. Unusually large tsunamis frequent a currently creeping part of the Aleutian megathrust

    NASA Astrophysics Data System (ADS)

    Witter, Robert C.; Carver, Gary A.; Briggs, Richard W.; Gelfenbaum, Guy; Koehler, Richard D.; La Selle, SeanPaul; Bender, Adrian M.; Engelhart, Simon E.; Hemphill-Haley, Eileen; Hill, Troy D.

    2016-01-01

    Current models used to assess earthquake and tsunami hazards are inadequate where creep dominates a subduction megathrust. Here we report geological evidence for large tsunamis, occurring on average every 300-340 years, near the source areas of the 1946 and 1957 Aleutian tsunamis. These areas bookend a postulated seismic gap over 200 km long where modern geodetic measurements indicate that the megathrust is currently creeping. At Sedanka Island, evidence for large tsunamis includes six sand sheets that blanket a lowland facing the Pacific Ocean, rise to 15 m above mean sea level, contain marine diatoms, cap terraces, adjoin evidence for scour, and date from the past 1700 years. The youngest sheet and modern drift logs found as far as 800 m inland and >18 m elevation likely record the 1957 tsunami. Previously unrecognized tsunami sources coexist with a presently creeping megathrust along this part of the Aleutian Subduction Zone.

  14. Unusually large tsunamis frequent a currently creeping part of the Aleutian megathrust

    USGS Publications Warehouse

    Witter, Robert C.; Carver, G.A.; Briggs, Richard; Gelfenbaum, Guy R.; Koehler, R.D.; La Selle, SeanPaul M.; Bender, Adrian M.; Engelhart, S.E.; Hemphill-Haley, E.; Hill, Troy D.

    2016-01-01

    Current models used to assess earthquake and tsunami hazards are inadequate where creep dominates a subduction megathrust. Here we report geological evidence for large tsunamis, occurring on average every 300–340 years, near the source areas of the 1946 and 1957 Aleutian tsunamis. These areas bookend a postulated seismic gap over 200 km long where modern geodetic measurements indicate that the megathrust is currently creeping. At Sedanka Island, evidence for large tsunamis includes six sand sheets that blanket a lowland facing the Pacific Ocean, rise to 15 m above mean sea level, contain marine diatoms, cap terraces, adjoin evidence for scour, and date from the past 1700 years. The youngest sheet, and modern drift logs found as far as 800 m inland and >18 m elevation, likely record the 1957 tsunami. Modern creep on the megathrust coexists with previously unrecognized tsunami sources along this part of the Aleutian Subduction Zone.

  15. On The Source Of The 25 November 1941 - Atlantic Tsunami

    NASA Astrophysics Data System (ADS)

    Baptista, M. A.; Lisboa, F. B.; Miranda, J. M. A.

    2015-12-01

    In this study we analyze the tsunami recorded in the North Atlantic following the 25 November 1941 earthquake. The earthquake with a magnitude of 8.3, located on the Gloria Fault, was one of the largest strike slip events recorded. The Gloria fault is a 500 km long scarp in the North Atlantic Ocean between 19W and 24W known to be a segment of the Eurasia-Nubia plate boundary between Iberia and the Azores. Ten tide stations recorded the tsunami. Six in Portugal (mainland, Azores and Madeira Islands), two in Morocco, one in the United Kingdom and one in Spain (Tenerife-Canary Islands). The tsunami waves reached Azores and Madeira Islands less than one hour after the main shock. The tide station of Casablanca (in Morocco) recorded the maximum amplitude of 0.54 m. All amplitudes recorded are lower than 0.5 m but the tsunami reached Portugal mainland in high tide conditions where the sea flooded some streets We analyze the 25 November 1941 tsunami data using the tide-records in the coasts of Portugal, Spain, Morocco and UK to infer its source. The use of wavelet analysis to characterize the frequency content of the tide-records shows predominant periods of 9-13min e 18-22min. A preliminary location of the tsunami source location was obtained Backward Ray Tracing (BRT). The results of the BRT technique are compatible with the epicenter location of the earthquake. We compute empirical Green functions for the earthquake generation area, and use a linear shallow water inversion technique to compute the initial water displacement. The comparison between forward modeling with observations shows a fair agreement with available data. This work 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)"

  16. The Three Tsunamis

    NASA Technical Reports Server (NTRS)

    Antcliff, Richard R.

    2007-01-01

    We often talk about how different our world is from our parent's world. We then extrapolate this thinking to our children and try to imagine the world they will face. This is hard enough. However, change is changing! The rate at which change is occurring is accelerating. These new ideas, technologies and ecologies appear to be coming at us like tsunamis. Our approach to responding to these oncoming tsunamis will frame the future our children will live in. There are many of these tsunamis; I am just going to focus on three really big ones heading our way.

  17. Firewaves: introducing a platform for modelling volcanic tsunamis

    NASA Astrophysics Data System (ADS)

    Paris, Raphaël; Ulvrova, Martina; Kelfoun, Karim; Giachetti, Thomas; Switzer, Adam

    2014-05-01

    When embracing all tsunamis generated by eruptive processes, rapid ground deformation and slope instability at volcanoes, "volcanic tsunamis" represent around 5 % of all tsunamis listed for the last four centuries (>130 events since 1600 AD). About 20-25 % of all fatalities directly attributable to volcanoes during the last 250 years have been caused by volcanic tsunamis (e.g. Krakatau 1883, Mayuyama 1792). Up to eight mechanisms are implied in the generation of volcanic tsunamis: underwater explosions, pyroclastic flows and lahars entering the water, earthquake preceding or during a volcanic eruption, and flank failure, collapse of coastal lava bench, caldera collapse, and shock wave produced by large explosion. It is unlikely that shock waves, lahars and collapses of lava bench can give birth to tsunamis with wave heights of more than 3 m. Pyroclastic flows, flank failures and caldera subsidence are the only source mechanisms likely to imply volumes larger than 1 km³. Volcanic tsunamis are characterised by short-period waves and greater dispersion compared to earthquake-generated tsunamis. With the exceptions of the 1888 Ritter Island and 1883 Krakatau tsunamis, 100 % of the victims of volcanic tsunamis in Southeast Asia were less than 20 km from the volcano. Travel time of the waves from the volcano to a distance of 20 km is typically less than 15 minutes (Paris et al. 2014). In this setting, priority are (1) to improve population's preparedness around highlighted volcanoes, (2) to monitor sea / lake around volcanoes, (3) and to build a database of numerical simulations based on different eruptive scenarios. The Firewaves platform, hosted at Magmas & Volcans laboratory in Clermont-Ferrand (FRance) is a numerical solution for modelling volcanic tsunamis of different sources. Tsunamis generated by volcanic mass flows (including pyroclastic flows, debris avalanches etc.) are simulated using VolcFlow code (Kelfoun et al. 2010), and underwater explosions and caldera

  18. Advanced Tsunami Numerical Simulations and Energy Considerations by use of 3D-2D Coupled Models: The October 11, 1918, Mona Passage Tsunami

    NASA Astrophysics Data System (ADS)

    López-Venegas, Alberto M.; Horrillo, Juan; Pampell-Manis, Alyssa; Huérfano, Victor; Mercado, Aurelio

    2015-06-01

    The most recent tsunami observed along the coast of the island of Puerto Rico occurred on October 11, 1918, after a magnitude 7.2 earthquake in the Mona Passage. The earthquake was responsible for initiating a tsunami that mostly affected the northwestern coast of the island. Runup values from a post-tsunami survey indicated the waves reached up to 6 m. A controversy regarding the source of the tsunami has resulted in several numerical simulations involving either fault rupture or a submarine landslide as the most probable cause of the tsunami. Here we follow up on previous simulations of the tsunami from a submarine landslide source off the western coast of Puerto Rico as initiated by the earthquake. Improvements on our previous study include: (1) higher-resolution bathymetry; (2) a 3D-2D coupled numerical model specifically developed for the tsunami; (3) use of the non-hydrostatic numerical model NEOWAVE (non-hydrostatic evolution of ocean WAVE) featuring two-way nesting capabilities; and (4) comprehensive energy analysis to determine the time of full tsunami wave development. The three-dimensional Navier-Stokes model tsunami solution using the Navier-Stokes algorithm with multiple interfaces for two fluids (water and landslide) was used to determine the initial wave characteristic generated by the submarine landslide. Use of NEOWAVE enabled us to solve for coastal inundation, wave propagation, and detailed runup. Our results were in agreement with previous work in which a submarine landslide is favored as the most probable source of the tsunami, and improvement in the resolution of the bathymetry yielded inundation of the coastal areas that compare well with values from a post-tsunami survey. Our unique energy analysis indicates that most of the wave energy is isolated in the wave generation region, particularly at depths near the landslide, and once the initial wave propagates from the generation region its energy begins to stabilize.

  19. Integrating TWES and Satellite-based remote sensing: Lessons learned from the Honshu 2011 Tsunami

    NASA Astrophysics Data System (ADS)

    Löwe, Peter; Wächter, Joachim

    2013-04-01

    The Boxing Day Tsunami killed 240,000 people and inundated the affected shorelines with waves reaching heights up to 30m. Tsunami Early Warning Capabilities have improved in the meantime by continuing development of modular Tsunami Early Warning Systems (TEWS). However, recent tsunami events, like the Chile 2010 and the Honshu 2011 tsunami demonstrate that the key challenge for TEWS research still lies in the timely issuing of reliable early warning messages to areas at risk, but also to other stakeholders professionally involved in the unfolding event. Until now remote sensing products for Tsunami events, including crisis maps and change detection products, are exclusively linked to those phases of the disaster life cycle, which follow after the early warning stage: Response, recovery and mitigation. The International Charter for Space and Major Disasters has been initiated by the European Space Agency (ESA) and the Centre National d'Etudes Spatiales (CNES) in 1999. It coordinates a voluntary group of governmental space agencies and industry partners, to provide rapid crisis imaging and mapping to disaster and relief organisations to mitigate the effects of disasters on human life, property and the environment. The efficiency of this approach has been demonstrated in the field of Tsunami early warning by Charter activations following the Boxing Day Tsunami 2004, the Chile Tsunami 2010 and the Honshu Tsunami 2011. Traditional single-satellite operations allow at best bimonthly repeat rates over a given Area of Interest (AOI). This allows a lot of time for image acquisition campaign planning between imaging windows for the same AOI. The advent of constellations of identical remote sensing satellites in the early 21st century resulted both in daily AOI revisit capabilities and drastically reduced time frames for acquisition planning. However, the image acquisition planning for optical remote sensing satellite constellations is constrained by orbital and communication

  20. Statistical Analysis of the Effectiveness of Seawalls and Coastal Forests in Mitigating Tsunami Impacts in Iwate and Miyagi Prefectures

    PubMed Central

    Nateghi, Roshanak; Bricker, Jeremy D.; Guikema, Seth D.; Bessho, Akane

    2016-01-01

    The Pacific coast of the Tohoku region of Japan experiences repeated tsunamis, with the most recent events having occurred in 1896, 1933, 1960, and 2011. These events have caused large loss of life and damage throughout the coastal region. There is uncertainty about the degree to which seawalls reduce deaths and building damage during tsunamis in Japan. On the one hand they provide physical protection against tsunamis as long as they are not overtopped and do not fail. On the other hand, the presence of a seawall may induce a false sense of security, encouraging additional development behind the seawall and reducing evacuation rates during an event. We analyze municipality-level and sub-municipality-level data on the impacts of the 1896, 1933, 1960, and 2011 tsunamis, finding that seawalls larger than 5 m in height generally have served a protective role in these past events, reducing both death rates and the damage rates of residential buildings. However, seawalls smaller than 5 m in height appear to have encouraged development in vulnerable areas and exacerbated damage. We also find that the extent of flooding is a critical factor in estimating both death rates and building damage rates, suggesting that additional measures, such as multiple lines of defense and elevating topography, may have significant benefits in reducing the impacts of tsunamis. Moreover, the area of coastal forests was found to be inversely related to death and destruction rates, indicating that forests either mitigated the impacts of these tsunamis, or displaced development that would otherwise have been damaged. PMID:27508461

  1. Statistical Analysis of the Effectiveness of Seawalls and Coastal Forests in Mitigating Tsunami Impacts in Iwate and Miyagi Prefectures.

    PubMed

    Nateghi, Roshanak; Bricker, Jeremy D; Guikema, Seth D; Bessho, Akane

    2016-01-01

    The Pacific coast of the Tohoku region of Japan experiences repeated tsunamis, with the most recent events having occurred in 1896, 1933, 1960, and 2011. These events have caused large loss of life and damage throughout the coastal region. There is uncertainty about the degree to which seawalls reduce deaths and building damage during tsunamis in Japan. On the one hand they provide physical protection against tsunamis as long as they are not overtopped and do not fail. On the other hand, the presence of a seawall may induce a false sense of security, encouraging additional development behind the seawall and reducing evacuation rates during an event. We analyze municipality-level and sub-municipality-level data on the impacts of the 1896, 1933, 1960, and 2011 tsunamis, finding that seawalls larger than 5 m in height generally have served a protective role in these past events, reducing both death rates and the damage rates of residential buildings. However, seawalls smaller than 5 m in height appear to have encouraged development in vulnerable areas and exacerbated damage. We also find that the extent of flooding is a critical factor in estimating both death rates and building damage rates, suggesting that additional measures, such as multiple lines of defense and elevating topography, may have significant benefits in reducing the impacts of tsunamis. Moreover, the area of coastal forests was found to be inversely related to death and destruction rates, indicating that forests either mitigated the impacts of these tsunamis, or displaced development that would otherwise have been damaged.

  2. Tsunami Damage in Northwest Sumatra

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The island of Sumatra suffered from both the rumblings of the submarine earthquake and the tsunamis that were generated on December 26, 2004. Within minutes of the quake, the sea surged ashore, bringing destruction to the coasts of the northern Sumatra. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite shows the Aceh province of northern Sumatra, Indonesia, on December 17, 2004, before the quake (bottom), and on December 29, 2004 (top), three days after the catastrophe. Although MODIS was not specifically designed to make the very detailed observations that are usually necessary for mapping coastline changes, the sensor nevertheless observed obvious differences in the Sumatran coastline. On December 17, the green vegetation along the west coast appears to reach all the way to the sea, with only an occasional thin stretch of white that is likely sand. After the earthquake and tsunamis, the entire western coast is lined with a noticeable purplish-brown border. The brownish border could be deposited sand, or perhaps exposed soil that was stripped bare of vegetation when the large waves rushed ashore and then raced away. Another possibility is that parts of the coastline may have sunk as the sea floor near the plate boundary rose. On a moderate-resolution image such as this, the affected area may seem small, but each pixel in the full resolution image is 250 by 250 meters. In places the brown strip reaches inland roughly 13 pixels, equal to a distance of 3.25 kilometers, or about 2 miles. On the northern tip of the island (shown in the large image), the incursion is even larger. NASA images created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team and the Goddard Earth Sciences DAAC.

  3. 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.

  4. 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

  5. Contribution of Urban Heat Island Effect to Urban Warming

    NASA Astrophysics Data System (ADS)

    Ma, Y.

    2013-12-01

    Urban heat island effect of Lanzhou city in china is analyzed using the average temperature, the maximum temperature and the minimum temperature during 1971-2008. Then the heat island intensity trends and contribution rates are calculated using the linear trends of three temperatures of Lanzhou city and the suburb. Results show that the differences of three temperatures between Lanzhou city and the suburb are all taking on increasing trends. The linear trends of average temperature, the maximum temperature and the minimum temperature are 0.3730C /10a,0.1870C /10a and 0.5200C /10a,respectively. The minimum temperature increases most obviously. In recent 38 years,temperatures increase mainly in the latter 19 years (1990-2008), and the linear trends of average temperature, maximum temperature and the minimum temperature of Lanzhou city are 0.6700C/10a,0.1180C/10a and 1.0320C/10a, respectively while those of the suburb are 0.6220C/10a, 0.0710C/10a and 1.130C/10a. The heat island contribution rates of three temperatures are 57.0%, 45.3% and 63.1%, respectively. The linear trends of average temperature and the minimum temperature in winter are the most in both city and the suburb, but the heat island contribution rate of the winter temperatures are not the largest, this possibly related with the severe air pollution in winter in Lanzhou city, because it can hold back urban heat island in some extent. In the latter 19 year,urban heat island effect of Lanzhou city was becoming stronger, but the contribution rates of average temperature and the maximum temperature are declining. This study is important to city planning and studying urbanization and the effect of environmental change on urban temperature.

  6. Numerical Tsunami Hazard Assessment of the Only Active Lesser Antilles Arc Submarine Volcano: Kick 'em Jenny.

    NASA Astrophysics Data System (ADS)

    Dondin, F. J. Y.; Dorville, J. F. M.; Robertson, R. E. A.

    2015-12-01

    The Lesser Antilles Volcanic Arc has potentially been hit by prehistorical regional tsunamis generated by voluminous volcanic landslides (volume > 1 km3) among the 53 events recognized so far. No field evidence of these tsunamis are found in the vincity of the sources. Such a scenario taking place nowadays would trigger hazardous tsunami waves bearing potentially catastrophic consequences for the closest islands and regional offshore oil platforms.Here we applied a complete hazard assessment method on the only active submarine volcano of the arc Kick 'em Jenny (KeJ). KeJ is the southernmost edifice with recognized associated volcanic landslide deposits. From the three identified landslide episodes one is associated with a collapse volume ca. 4.4 km3. Numerical simulations considering a single pulse collapse revealed that this episode would have produced a regional tsunami. An edifice current volume estimate is ca. 1.5 km3.Previous study exists in relationship to assessment of regional tsunami hazard related to shoreline surface elevation (run-up) in the case of a potential flank collapse scenario at KeJ. However this assessment was based on inferred volume of collapse material. We aim to firstly quantify potential initial volumes of collapse material using relative slope instability analysis (RSIA); secondly to assess first order run-ups and maximum inland inundation distance for Barbados and Trinidad and Tobago, i.e. two important economic centers of the Lesser Antilles. In this framework we present for seven geomechanical models tested in the RSIA step maps of critical failure surface associated with factor of stability (Fs) for twelve sectors of 30° each; then we introduce maps of expected potential run-ups (run-up × the probability of failure at a sector) at the shoreline.The RSIA evaluates critical potential failure surface associated with Fs <1 as compared to areas of deficit/surplus of mass/volume identified on the volcanic edifice using (VolcanoFit 2

  7. 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.

  8. New Edition of the UNESCO-IOC International Tsunami Survey Team (ITST) Post-Tsunami Survey Field Guide

    NASA Astrophysics Data System (ADS)

    Dengler, L.; Dominey-Howes, D.; Yamamoto, M.; Borrero, J. C.; Dunbar, P. K.; Fritz, H. M.; Imamura, F.; Kong, L. S.; Koshimura, S.; McAdoo, B. G.; Satake, K.; Yalciner, A. C.; Yulianto, E.

    2011-12-01

    A subcommittee of the IUGG International Tsunami Commission was convened in 2010 to revise and update the 1998 UNESCO-IOC Post-Tsunami Survey Field Guide. The revised Guide addresses the developments in the tsunami field since 1998, the need to accommodate vastly increased amounts of data, and to incorporate disciplines that were not covered in the original guide. The Guide also advocates a systems-approach to assessing tsunami impacts that examines the full range of physical, environmental, and socio-economic effects and their interrelationship, bringing tsunami research efforts into a closer alignment with the UN International Strategy for Disaster Reduction (UNISDR). This Field Guide is intended to provide a flexible framework to facilitate the acquisition of critical data in the immediate aftermath of significant tsunamis and to balance the needs of international researchers with those of communities and agencies involved with response and recovery. It will be of use to a variety of people and organizations who may either participate in, assist in coordination, or host post-tsunami field surveys. It is hoped that this Guide will promote pre-event planning in countries at risk of tsunamis to reduce the stresses of developing organizational logistics in the post-emergency response phase and make the process of conducting an ITST easier and more productive for both participating researchers and host country organizations. A complete draft of the Guide will be presented at the meeting and members of the tsunami community invited to comment.

  9. Tsunami arrival time detection system applicable to discontinuous time series data with outliers

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Whan; Park, Sun-Cheon; Lee, Duk Kee; Lee, Jong Ho

    2016-12-01

    Timely detection of tsunamis with water level records is a critical but logistically challenging task because of outliers and gaps. Since tsunami detection algorithms require several hours of past data, outliers could cause false alarms, and gaps can stop the tsunami detection algorithm even after the recording is restarted. In order to avoid such false alarms and time delays, we propose the Tsunami Arrival time Detection System (TADS), which can be applied to discontinuous time series data with outliers. TADS consists of three algorithms, outlier removal, gap filling, and tsunami detection, which are designed to update whenever new data are acquired. After calibrating the thresholds and parameters for the Ulleung-do surge gauge located in the East Sea (Sea of Japan), Korea, the performance of TADS was discussed based on a 1-year dataset with historical tsunamis and synthetic tsunamis. The results show that the overall performance of TADS is effective in detecting a tsunami signal superimposed on both outliers and gaps.

  10. Observed and Modeled Currents from the Tohoku-oki, Japan and other Recent Tsunamis in Northern California

    NASA Astrophysics Data System (ADS)

    Admire, Amanda R.; Dengler, Lori A.; Crawford, Gregory B.; Uslu, Burak U.; Borrero, Jose C.; Greer, S. Dougal; Wilson, Rick I.

    2014-12-01

    We investigate the currents produced by recent tsunamis in Humboldt Bay and Crescent City, California. The region is susceptible to both near-field and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 kms north of Humboldt Bay, suffered US 28 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US 26 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600 kHz 2D acoustic Doppler current profiler (ADCP) with a 1-min sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the Mw 8.8 Chile earthquake on February 27, 2010 and the Mw 9.0 Japan earthquake on March 11, 2011. One other tsunami was recorded on the Humboldt Bay tide gauge during the period of ADCP operation, but was not visible on the ADCP, suggesting a threshold water level value of about 0.2 m to produce an observable ADCP record. The 2010 tsunami currents persisted in Humboldt Bay for approximately 30 h with peak amplitudes of about 0.35 m/s. The 2011 tsunami signal lasted for over 40 h with peak amplitude of 0.84 m/s. The strongest currents corresponded to the maximum change in water level approximately 67 min after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and one-half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master, approximately 70 m away from the NOAA-NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities

  11. 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

  12. Tsunamis: Sanitation and Hygiene

    MedlinePlus

    ... About CDC.gov . Natural Disasters and Severe Weather Earthquakes Being Prepared Emergency Supplies Home Hazards Indoor Safety ... Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis Volcanoes ...

  13. The Algorithm Development of the Tsunami Impact Intensity Analysis and the Application to the 1867 Keelung Tsunami Event

    NASA Astrophysics Data System (ADS)

    Wu, T. R.; Wu, H.; Li, P. Y.; Lee, C. J.; Tsai, Y. L.; Chuang, M. H.

    2015-12-01

    As a tsunami scientist, I've been frequently asked where the tsunami will/did come from? The conventional answer to this question is based on the understanding of trench and bathymetry distributions. Sometimes, for a precise answer, a series of scenario studies have to be performed in priori. Even hundreds of scenarios are created and studied, however, potential tsunami sources could be neglected unintentionally.. For this, I've created a new algorithm to efficiently locate the possible tsunami sources, which is called Impact Intensity Analysis (IIA). Briefly speaking, this algorithm scans the entire computational domain and find out the distribution of maximum wave height of each unit source. After that, the result presents a clear view of potential tsunami energy transport pattern. For example, the result of IIA shows that the southern east of Taiwan is under the threat of tsunamis sourcing from the northern segment of Yap Trench; and so is the northern segment of Manila Trench. A clear energy path can be seen, linking Taiwan and the Yap Trench. The result matches the scenario study of potential Yap tsunami very well (Figure 1). This indicates that once the tsunami source is located in the energy path, with a proper wave direction, the tsunami energy can be transported to the study site with relatively less energy loss. Therefore, this algorithm can help us analyze the potential tsunami source systematically; and more importantly, get rid of the impossible source candidates quickly. In this paper, we present the detailed validation of this algorithm, including the directionality and the effect of on and off the energy path. At the end, we employ this algorithm to analyze the potential tsunami source of 1867 Keelung tsunami event. The result shows that this event was possibly caused by a submarine landslide generated tsunami and the landslide occurred in the north-east offshore Taiwan.Figure 1. The Impact Intensity Analysis (IIA) of the south-east Taiwan (left

  14. Role of depositional environments in the preservation and detection of past tsunamis: lessons from 2004 Indian Ocean tsunami

    NASA Astrophysics Data System (ADS)

    Rajendran, Kusala; Chittenipattu, Rajendran; Andrade, Vanessa

    2013-04-01

    Reconstructing the tsunamigenic earthquake history of a region aids hazard assessment, and in the absence of written records, tsunami geology is the only tool to constrain the chronology and magnitudes of previous tsunamis to have affected a region. Observations along the Andaman-Nicobar Islands and the east coast of India suggest that distant and geomorphologically sheltered sites provide more conducive environments for tsunami deposition and preservation. The 2004 deposits from the Andaman Islands are mainly organic debris, sand sheets, coral debris and boulder deposits. The 2004 coseismic deformational features include uplift and subsidence of land as well as soil liquefaction. We use sites of tsunami deposits and deformational features to obtain evidence leading to past tsunamigenic earthquakes. The study spans latitudes from 7-14° N, from Campbell Bay to East Island. We classify the ages into three grades, A, B and C, based on the stratigraphic context of the deposit and the material and the age uncertainties. The earliest of the tsunamis occurred between 2nd and 6th centuries AD, evidenced by the coastal boulder beds of the southern Car Nicobar Island. A subsequent tsunami probably in the age range AD 770-1040 is inferred from both the Andaman and Nicobar Islands and on the Indian subcontinent. It is the strongest candidate for a 2004-caliber earthquake in the past 1500 years or more. The A&N Islands also contain tsunami deposits from AD 1250-1450 that probably matches those previously reported from Sumatra and Thailand. Evidence from what we consider as protected inland sites as well as coseismic deformation and liquefaction fall in the same age brackets as AD 1250-1450 from Indonesia, Thailand and AD 770-1040, from Indonesia, Sri Lanka and the east coast of India. By using deposits from the inland locations within the rupture as well as transoceanic sites, and other proxies dated in the same age bracket, we suggest that the ~1000 year old earthquake best

  15. Type 19 Flood Insurance Study: Tsunami Predictions for Southern California.

    DTIC Science & Technology

    1980-09-01

    elevation that occurs during a typical year. For example, the maximum combined tsunami and astronomical tide 41 elevation during the last 100 yr at Rincon ...at Rincon Island). The maximum combined elevation was approximately 3.5 ft above msl. This elevation is greater than mean higher high water (2.8 ft...but less than the maximum astronomical tide elevation that typically occurs during the average year at Rincon Island. Thus the fact that the combined

  16. Cost-Effectiveness Analysis of the Residential Provisions of the 2015 IECC for Rhode Island

    SciTech Connect

    Mendon, Vrushali V.; Zhao, Mingjie; Taylor, Zachary T.; Poehlman, Eric A.

    2016-02-15

    The 2015 IECC provides cost-effective savings for residential buildings in Rhode Island. Moving to the 2015 IECC from the 2012 IECC base code is cost-effective for residential buildings in all climate zones in Rhode Island.

  17. Tsunami hazard assessment for the Azores archipelago: a historical review

    NASA Astrophysics Data System (ADS)

    Cabral, Nuno; Ferreira, Teresa; Queiroz, Maria Gabriela

    2010-05-01

    The Azores islands due to its complex geographical and geodynamic setting are exposed to tsunamigenic events associated to different triggering mechanisms, local or distant. Since the settlement of the Azores, in the fifteenth century, there are several documents that relate coastal areas flooding episodes with unusually high waves which caused death and destruction. This work had as main objective the characterization of the different events that can be associated with tsunamigenic phenomena, registered in the archipelago. With this aim, it was collected diverse documentation like chronics, manuscripts, newspaper articles and magazines, scientific publications, and international databases available online. From all the studied tsunami events it was identified the occurrence of some teletsunamis, among which the most relevant was triggered by the 1st November 1755 Lisbon earthquake, with an epicenter SW of Portugal, which killed 6 people in Terceira island. It is also noted the teletsunami generated by the 1761 earthquake, located in the same region as the latest, and the one generated in 1929 by an earthquake-triggered submarine landslide in the Grand Banks of Newfoundland. From the local events, originated in the Azores, the most significant were the tsunamis triggered by 1757 and 1980 earthquakes, both associated with the Terceira Rift dynamics. In the first case the waves may also be due to earthquake-triggered. With respect to tsunamis triggered by sea cliffs landslides it is important to mention the 1847 Quebrada Nova and the 1980 Rocha Alta events, both located in the Flores Island. The 1847 event is the deadliest tsunami recorded in Azores since 10 people died in Flores and Corvo islands in result of the propagated wave. The developed studies improve knowledge of the tsunami sources that affected the Azores during its history, also revealing the importance of awareness about this natural phenomenon. The obtained results showed that the tsunami hazard in the

  18. 1883 Krakatau Tsunami Deposits In Teluk Banten (nw Java, Indonesia)

    NASA Astrophysics Data System (ADS)

    van den Bergh, G. D.; van Weering, Tj. C. E.; de Haas, H.

    Teluk Banten is a shallow (less than 10 m deep) marine embayment with coral reef islands, close to the Krakatau volcanic complex and facing the Java Sea to the North. The 1883 Krakatau eruption generated a tsunami, which had a devastating effect on the neighboring coastal areas. In Teluk Banten the wave height was estimated to have been around 1.8 m. Relatively little is known about the effects of this tsunami on the sea floor. We have assessed the effects of the 1883 Krakatau eruption and the associ- ated tsunami on the bottom sediments in Teluk Banten by studying numerous bottom samples that were collected in and outside Teluk Banten with a gravity corer. On these cores we performed magnetic susceptibility measurements, XRF major element anal- ysis, grain size analysis and analysis of the downcore distribution of 210Pb isotopes. X-ray photographs were also taken of a number of cores. The 1883 tsunami layer has been identified in these bottom samples based on textural, compositional and 210Pb geochronological data. An important diagnostic criterion consists of the occurrence of tephra conform descriptions given of the tephra associated with the 1883 eruption. The spatial variability of the tsunamite in and outside Teluk Banten is described. The tsunamite consists of a sandy layer with abundant reworked shell and other carbon- ate fragments. Coarse clastic components in the tsunamite consist of locally derived material eroded from the marine bottom sediments (mostly pellets) and tephra. Only at close proximity to the south coast also land-derived components are incorporated in the tsunamite. The tsunamite has its thickest development in localized areas of the central bay. Along the northern seaward facing slope of the bay the tsunamite is best preserved, as little post-depositional modifications have occurred here. In the Eastern bay area subsequent erosion has supposedly removed the Krakatau event layer com- pletely. Along the West coast of Teluk Banten the only

  19. LIDAR Investigations of the 2009 American Samoa Tsunami

    NASA Astrophysics Data System (ADS)

    Donahue, J. L.; Olsen, M. J.

    2009-12-01

    A reconnaissance team was mobilized to American Samoa and Western Samoa in the days that followed the Mw 8.0 earthquake and destructive tsunami. The Geo-Engineering Extreme Events Reconnaissance (GEER) team was assembled to investigate the geotechnical effects of both the earthquake event and the tsunami effects on the coastal environment. The team also made observations on structural engineering and lifeline aspects, although these were not the primary focus. The GEER team employed a number of useful technologies to facilitate effective reconnaissance. Each team member utilized a common GPS unit and laptop with a Google Earth GIS database to track visited locations. The team also deployed with LIDAR equipment to map areas of tsunami devastation to include scour, erosion, and structural damage. The LIDAR scanning was performed in Pago Pago, Alao, Tula, Leone and Poloa on the island of Western Samoa. In Pago Pago, the scans map the location of several debris piles and damaged structures. In Alao, scour around a foundation was mapped using the TLS. The structure atop the foundation was completely destroyed. Finally, the scans also show the location of beach sediment that was washed up off of the beach. In Tula, scans were performed to show the damages to several buildings in the village. A scan was done adjacent to the beach to show some of the coastal erosion and damages and map sediment dislocation. In Leone, structural damage to buildings and bridges were mapped (see Figure). The scans also map scouring along a rock wall along the riverside and a substantial amount of erosion that occurred along one of the river banks. In the village of Poloa, scans show the location of the trim line, where the tsunami waves reached. Also, damages to structures, such as a school building, were recorded along with the location of fresh coral deposited on the beach, scour and erosion. The LIDAR data was important to the investigation for multiple reasons. First, it provided a quick

  20. Tsunami: Ocean dynamo generator

    PubMed Central

    Sugioka, Hiroko; Hamano, Yozo; Baba, Kiyoshi; Kasaya, Takafumi; Tada, Noriko; Suetsugu, Daisuke

    2014-01-01

    Secondary magnetic fields are induced by the flow of electrically conducting seawater through the Earth's primary magnetic field (‘ocean dynamo effect’), and hence it has long been speculated that tsunami flows should produce measurable magnetic field perturbations, although the signal-to-noise ratio would be small because of the influence of the solar magnetic fields. Here, we report on the detection of deep-seafloor electromagnetic perturbations of 10-micron-order induced by a tsunami, which propagated through a seafloor electromagnetometer array network. The observed data extracted tsunami characteristics, including the direction and velocity of propagation as well as sea-level change, first to verify the induction theory. Presently, offshore observation systems for the early forecasting of tsunami are based on the sea-level measurement by seafloor pressure gauges. In terms of tsunami forecasting accuracy, the integration of vectored electromagnetic measurements into existing scalar observation systems would represent a substantial improvement in the performance of tsunami early-warning systems. PMID:24399356

  1. 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

  2. Health effects of the nuclear accident at Three Mile Island

    SciTech Connect

    Fabrikant, J.I.

    1980-05-01

    Between March 28 and April 15, 1979 the collective dose resulting from the radioactivity released to the population living within a 50-mile radius of the Three Mile Island nuclear plant was about 2000 person-rems, less than 1% of the annual natural background level. The average dose to a person living within 5 miles of the nuclear plant was less than 10% of annual background radiation. The maximum estimated radiation dose received by any one individual in the general population (excluding the nuclear plant workers) during the accident was 70 mrem. The doses received by the general population as a result of the accident were so small that there will be no detectable additional cases of cancer, developmental abnormalities, or genetic ill-health. Three Three Mile Island nuclear workers received radiation doses of about 3 to 4 rem, exceeding maximum permissible quarterly dose of 3 rem. The major health effect of the accident at Three Mile Island was that of a pronounced demoralizing effect on the general population in the Three Mile Island area, including teenagers and mothers of preschool children and the nuclear plant workers. However, this effect proved transient in all groups studied except the nuclear workers.

  3. Response to the 2011 Great East Japan Earthquake and Tsunami disaster.

    PubMed

    Koshimura, Shunichi; Shuto, Nobuo

    2015-10-28

    We revisited the lessons of the 2011 Great East Japan Earthquake Tsunami disaster specifically on the response and impact, and discussed the paradigm shift of Japan's tsunami disaster management policies and the perspectives for reconstruction. Revisiting the modern histories of Tohoku tsunami disasters and pre-2011 tsunami countermeasures, we clarified how Japan's coastal communities have prepared for tsunamis. The discussion mainly focuses on structural measures such as seawalls and breakwaters and non-structural measures of hazard map and evacuation. The responses to the 2011 event are discussed specifically on the tsunami warning system and efforts to identify the tsunami impacts. The nation-wide post-tsunami survey results shed light on the mechanisms of structural destruction, tsunami loads and structural vulnerability to inform structural rehabilitation measures and land-use planning. Remarkable paradigm shifts in designing coastal protection and disaster mitigation measures were introduced, leading with a new concept of potential tsunami levels: Prevention (Level 1) and Mitigation (Level 2) levels according to the level of 'protection'. The seawall is designed with reference to Level 1 tsunami scenario, while comprehensive disaster management measures should refer to Level 2 tsunami for protection of human lives and reducing potential losses and damage. Throughout the case study in Sendai city, the proposed reconstruction plan was evaluated from the tsunami engineering point of view to discuss how the post 2011 paradigm was implemented in coastal communities for future disaster mitigation. The analysis revealed that Sendai city's multiple protection measures for Level 2 tsunami will contribute to a substantial reduction of the tsunami inundation zone and potential losses, combined with an effective tsunami evacuation plan.

  4. Tsunami hazard potential for the equatorial southwestern Pacific atolls of Tokelau from scenario-based simulations

    NASA Astrophysics Data System (ADS)

    Orpin, A. R.; Rickard, G. J.; Gerring, P. K.; Lamarche, G.

    2015-07-01

    Devastating tsunami over the last decade have significantly heightened awareness of the potential consequences and vulnerability to tsunami for low-lying Pacific islands and coastal regions. Our tsunami risk assessment for the atolls of the Tokelau Islands was based on a tsunami source-propagation-inundation model using Gerris Flow Solver, adapted from the companion study by Lamarche et al. (2015) for the islands of Wallis and Futuna. We assess whether there is potential for tsunami flooding on any of the village islets from a series of fourteen earthquake-source experiments that apply a combination of well-established fault parameters to represent plausible "high-risk scenarios" for each of the tsunamigenic sources. Earthquake source location and moment magnitude were related to tsunami wave heights and tsunami flood depths simulated for each of the three atolls of Tokelau. This approach was adopted to yield indicative and instructive results for a community advisory, rather than being fully deterministic. Results from our modelling show that wave fields are channelled by the bathymetry of the Pacific basin in such a way that the swathes of the highest waves sweep immediately northeast of the Tokelau Islands. From our series of limited simulations a great earthquake from the Kuril Trench poses the most significant inundation threat to Tokelau, with maximum modelled-wave heights in excess of 1 m, which may last a few hours and include several wave trains. Other sources can impact specific sectors of the atolls, particularly from regional sources to the south, and northern and eastern distant sources that generate trans-Pacific tsunami. In many cases impacts are dependent on the wave orientation and direct exposure to the oncoming tsunami. This study shows that dry areas remain around the villages in nearly all our "worst-case" tsunami simulations of the Tokelau Islands. Consistent with the oral history of little or no perceived tsunami threat, simulations from the

  5. Tsunamis on the Pacific Coast of Canada Recorded in 1994-2007

    NASA Astrophysics Data System (ADS)

    Stephenson, Frederick E.; Rabinovich, Alexander B.

    2009-02-01

    In the last 15 years there have been 16 tsunami events recorded at tide stations on the Pacific Coast of Canada. Eleven of these events were from distant sources covering almost all regions of the Pacific, as well as the December 26, 2004 Sumatra tsunami in the Indian Ocean. Three tsunamis were generated by local or regional earthquakes and two were meteorological tsunamis. The earliest four events, which occurred in the period 1994-1996, were recorded on analogue recorders; these tsunami records were recently re-examined, digitized and thoroughly analysed. The other 12 tsunami events were recorded using digital high-quality instruments, with 1-min sampling interval, installed on the coast of British Columbia (B.C.) in 1998. All 16 tsunami events were recorded at Tofino on the outer B.C. coast, and some of the tsunamis were recorded at eight or more stations. The tide station at Tofino has been in operation for 100 years and these recent observations add to the dataset of tsunami events compiled previously by S.O. W igen (1983) for the period 1906-1980. For each of the tsunami records statistical analysis was carried out to determine essential tsunami characteristics for all events (arrival times, maximum amplitudes, frequencies and wave-train structure). The analysis of the records indicated that significant background noise at Langara, a key northern B.C. Tsunami Warning station located near the northern end of the Queen Charlotte Islands, creates serious problems in detecting tsunami waves. That station has now been moved to a new location with better tsunami response. The number of tsunami events observed in the past 15 years also justified re-establishing a tide gauge at Port Alberni, where large tsunami wave amplitudes were measured in March 1964. The two meteorological events are the first ever recorded on the B.C. coast. Also, there have been landslide generated tsunami events which, although not recorded on any coastal tide gauges, demonstrate, along with

  6. Field Survey of the 27 February 2010 Chile Tsunami

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Petroff, Catherine M.; Catalán, Patricio A.; Cienfuegos, Rodrigo; Winckler, Patricio; Kalligeris, Nikos; Weiss, Robert; Barrientos, Sergio E.; Meneses, Gianina; Valderas-Bermejo, Carolina; Ebeling, Carl; Papadopoulos, Athanassios; Contreras, Manuel; Almar, Rafael; Dominguez, Juan Carlos; Synolakis, Costas E.

    2011-11-01

    On 27 February 2010, a magnitude M w = 8.8 earthquake occurred off the coast of Chile's Maule region causing substantial damage and loss of life. Ancestral tsunami knowledge from the 1960 event combined with education and evacuation exercises prompted most coastal residents to spontaneously evacuate after the earthquake. Many of the tsunami victims were tourists in coastal campgrounds. The international tsunami survey team (ITST) was deployed within days of the event and surveyed 800 km of coastline from Quintero to Mehuín and the Pacific Islands of Santa María, Mocha, Juan Fernández Archipelago, and Rapa Nui (Easter). The collected survey data include more than 400 tsunami flow depth, runup and coastal uplift measurements. The tsunami peaked with a localized runup of 29 m on a coastal bluff at Constitución. The observed runup distributions exhibit significant variations on local and regional scales. Observations from the 2010 and 1960 Chile tsunamis are compared.

  7. 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).

  8. The November 17, 2015 Lefkada offshore (non-?)tsunamigenic earthquake: preliminary considerations and implications for tsunami hazard and warning in the Ionian Sea

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    A Mw = 6.5 earthquake occurred on November 17, 2015 just offshore the western coast of the Ionian island of Lefkada (western Greece). The earthquake caused two fatalities and severe damage, especially in the island of Lefkada. Several landslides were set in motion by the earthquake, some of which occurred along the coastal cliffs. The earthquake was clearly felt also along the eastern coasts of Apulia, Calabria and Sicily (Italy). The computed focal mechanisms indicate that the rupture occurred along a dextral strike-slip, sub-vertical fault, compatible with the well-known transcurrent tectonics of the Lefkada-Cephalonia area. At the time of the drafting of this abstract no heterogeneous slip distribution has been proposed. No clear evidence of tsunami effects is available, with the only exception of the signal recorded by the tide gauge in Crotone (eastern Calabria, Italy), where a clear disturbance (still to be fully characterised and explained) emerges from the background at approximately 1 hour after the earthquake origin time. From the tsunami research point of view, the November 17 Lefkada earthquake poses at least two problems, which we try to address in this paper. The first consists in studying the tsunami generation based on the available seismic information and on the tectonic setting of the area. We present results of numerical simulations of the tsunami generation and propagation aimed at casting light on the reasons why the generated tsunami was so weak (or even absent). Starting from the official fault parameters provided by the seismic agencies, we vary a number of them, there including the length and width calculated on the basis of different regression formulas, and the depth. For each configuration we perform tsunami simulations by means of the in-house finite-difference code UBO-TSUFD. In parallel, we analyse the Crotone tide-gauge record in order to understand whether the observed "anomalous" signal can be attributed to a tsunami or not. In the

  9. Self Organization of Pb Islands on Si(111) Caused by Quantum Size Effects

    NASA Astrophysics Data System (ADS)

    Hong, Hawoong; Basile, Leo; Czoschke, Peter; Gray, Aaron; Chiang, Tai-Chang

    2007-03-01

    Growth of metallic Pb islands on Si(111) by vacuum deposition was studied in real time using synchrotron x-ray diffraction. The islands coarsen and order, maintaining a nearly uniform inter-island distance but without angular correlation. The resulting inter-island structure is akin to a two-dimensional liquid. Over a wide temperature range, the inter-island ordering is well correlated with the development of ``magic'' island heights caused by energy minimization of the Pb electrons. The results demonstrate quantum confinement effects as a driving force for self organization, as opposed to strain effects that generally govern the formation of semiconductor quantum dot arrays.

  10. A detail modeling of the 1960 and 2010 Chilean tsunami over French Polynesia: consequencies and improvements of the tsunami warning system.

    NASA Astrophysics Data System (ADS)

    Reymond, Dominique; Jamelot, Anthony

    2015-04-01

    We present here a detail study of the last two major tsunami events of Chile that were observed significantly in Tahiti : the tsunami on May 22, 1960 of Valdivia generated by the strongest earthquake ever recorded (Mw=9.5) and the tsunami of the February 27, 2010 of Maule (Mw=8.8). In a first step, using numerical modeling, we will tune the seismic sources parameters to reproduce the tsunami heights given by the field-survey observations , testimonies and tide gages measurements made in Tahiti and Marquesas islands with the cartography of that time. Then from that validation, we are able to study these tsunamis more precisely to evaluate their coastal impacts on the actual shore of 2015 using recent tsunami inundation elevation models. We also study the sensibility of the tsunami height over the Polynesian coasts by modeling the impact of the tide (about 0.6 m in Tahiti and 1.30 m in Marquesas islands) but also punctual rises of the sea level induced by extreme meteorological phenomena like cyclonic waves, tropical storm or tropical rains that can each increase drastically the sea level of the lagoon around Tahiti by one meter or more. As a practical consequence of this study, the French Polynesia tsunami warning system could plan to take into account the tide in the warning context for a more accurate inundation forecast. Moreover, we can consider that a better understanding of catastrophic events that would combine a tsunami with an extreme meteorological phenomena will contribute to update the tsunami hazard knowledge of Tahiti.

  11. Effects of roads on survival of San Clemente Island foxes

    USGS Publications Warehouse

    Snow, N.P.; Andelt, W.F.; Stanley, T.R.; Resnik, J.R.; Munson, L.

    2012-01-01

    Roads generate a variety of influences on wildlife populations; however, little is known about the effects of roads on endemic wildlife on islands. Specifically, road-kills of island foxes (Urocyon littoralis) on San Clemente Island (SCI), Channel Islands, California, USA are a concern for resource managers. To determine the effects of roads on island foxes, we radiocollared foxes using a 3-tiered sampling design to represent the entire population in the study area, a sub-population near roads, and a sub-population away from roads on SCI. We examined annual survival rates using nest-survival models, causes of mortalities, and movements for each sample. We found the population had high annual survival (0.90), although survival declined with use of road habitat, particularly for intermediate-aged foxes. Foxes living near roads suffered lower annual survival (0.76), resulting from high frequencies of road-kills (7 of 11 mortalities). Foxes living away from roads had the highest annual survival (0.97). Road-kill was the most prominent cause of mortality detected on SCI, which we estimated as killing 3-8% of the population in the study area annually. Based on movements, we were unable to detect any responses by foxes that minimized their risks from roads. The probabilities of road-kills increased with use of the road habitat, volume of traffic, and decreasing road sinuosity. We recommend that managers should attempt to reduce road-kills by deterring or excluding foxes from entering roads, and attempting to modify behaviors of motorists to be vigilant for foxes. ?? 2011 The Wildlife Society.

  12. 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

  13. 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

  14. Local tsunamis and earthquake source parameters

    USGS Publications Warehouse

    Geist, Eric L.; Dmowska, Renata; Saltzman, Barry

    1999-01-01

    This chapter establishes the relationship among earthquake source parameters and the generation, propagation, and run-up of local tsunamis. In general terms, displacement of the seafloor during the earthquake rupture is modeled using the elastic dislocation theory for which the displacement field is dependent on the slip distribution, fault geometry, and the elastic response and properties of the medium. Specifically, nonlinear long-wave theory governs the propagation and run-up of tsunamis. A parametric study is devised to examine the relative importance of individual earthquake source parameters on local tsunamis, because the physics that describes tsunamis from generation through run-up is complex. Analysis of the source parameters of various tsunamigenic earthquakes have indicated that the details of the earthquake source, namely, nonuniform distribution of slip along the fault plane, have a significant effect on the local tsunami run-up. Numerical methods have been developed to address the realistic bathymetric and shoreline conditions. The accuracy of determining the run-up on shore is directly dependent on the source parameters of the earthquake, which provide the initial conditions used for the hydrodynamic models.

  15. The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

    USGS Publications Warehouse

    Ross, Stephanie; Jones, Lucile

    2013-01-01

    The Science Application for Risk Reduction (SAFRR) tsunami scenario depicts a hypothetical but plausible tsunami created by an earthquake offshore from the Alaska Peninsula and its impacts on the California coast. The tsunami scenario is a collaboration between the U.S. Geological Survey (USGS), the California Geological Survey (CGS), the California Governor’s Office of Emergency Services (Cal OES), the National Oceanic and Atmospheric Administration (NOAA), other Federal, State, County, and local agencies, private companies, and academic and other institutions. This document presents evidence for past tsunamis, the scientific basis for the source, likely inundation areas, current velocities in key ports and harbors, physical damage and repair costs, economic consequences, environmental and ecological impacts, social vulnerability, emergency management and evacuation challenges, and policy implications for California associated with this hypothetical tsunami. We also discuss ongoing mitigation efforts by the State of California and new communication products. The intended users are those who need to make mitigation decisions before future tsunamis, and those who will need to make rapid decisions during tsunami events. The results of the tsunami scenario will help managers understand the context and consequences of their decisions and how they may improve preparedness and response. An evaluation component will assess the effectiveness of the scenario process for target stakeholders in a separate report to improve similar efforts in the future.

  16. Dynamic models of an earthquake and tsunami offshore Ventura, California

    USGS Publications Warehouse

    Kenny J. Ryan,; Geist, Eric L.; Barall, Michael; David D. Oglesby,

    2015-01-01

    The Ventura basin in Southern California includes coastal dip-slip faults that can likely produce earthquakes of magnitude 7 or greater and significant local tsunamis. We construct a 3-D dynamic rupture model of an earthquake on the Pitas Point and Lower Red Mountain faults to model low-frequency ground motion and the resulting tsunami, with a goal of elucidating the seismic and tsunami hazard in this area. Our model results in an average stress drop of 6 MPa, an average fault slip of 7.4 m, and a moment magnitude of 7.7, consistent with regional paleoseismic data. Our corresponding tsunami model uses final seafloor displacement from the rupture model as initial conditions to compute local propagation and inundation, resulting in large peak tsunami amplitudes northward and eastward due to site and path effects. Modeled inundation in the Ventura area is significantly greater than that indicated by state of California's current reference inundation line.

  17. Real time assessment of the 15 July 2009 New Zealand tsunami

    NASA Astrophysics Data System (ADS)

    Uslu, Burak; Power, William; Greensdale, Dianne; Titov, Vasily

    2010-05-01

    On the 15th July 2009 a Mw 7.6 earthquake occurred off the coast of Fiordland in the South Island of New Zealand, about 1200 km from Auckland, New Zealand, 1500 km from Hobart, Tasmania and 1800 km from Sydney, Australia. A tsunami was generated and an initial warning issued by the PTWC. The Centre for Australian Weather and Climate issued its first tsunami warning for coastal regions of eastern Australia and New Zealand 24 minutes after the earthquake. By serendipitous coincidence, the earthquake struck while the International Tsunami Symposium was in session in Novosibirsk Russia. This provided the opportunity to test, in real-time, several tsunami warning systems in front of attending scientists (Schiermeier, 2009). NOAA Center for Tsunami Research, Pacific Tsunami Warning Center, GNS Science, and Centre for Australian Weather and Climate scientists were present at the symposium and worked together. Vasily Titov showed "live" NOAA's methodology (Bernard et al, 2006) to assess the tsunami potential and, in consultation with colleagues, provided warning guidance, and the warning was eventually canceled. We discuss how the forecast was done and how accurate the initial determination was. References Bernard E.N. et al., 2006, Tsunami: scientific frontiers, mitigation, forecasting and policy implications, Phil. Trans. R. Soc. A, 364:1989-2007; doi:10.1098/rsta.2006.1809 Schiermeier, Q., 2009, Tsunami forecast in real time, Published online 16 July 2009 | Nature | doi:10.1038/news.2009.702

  18. 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.

  19. 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.

  20. CARIBE WAVE/LANTEX Caribbean and Western Atlantic Tsunami Exercises

    NASA Astrophysics Data System (ADS)

    von Hillebrandt-Andrade, C.; Whitmore, P.; Aliaga, B.; Huerfano Moreno, V.

    2013-12-01

    Over 75 tsunamis have been documented in the Caribbean and Adjacent Regions over the past 500 years. While most have been generated by local earthquakes, distant generated tsunamis can also affect the region. For example, waves from the 1755 Lisbon earthquake and tsunami were observed in Cuba, Dominican Republic, British Virgin Islands, as well as Antigua, Martinique, Guadalupe and Barbados in the Lesser Antilles. Since 1500, at least 4484 people are reported to have perished in these killer waves. Although the tsunami generated by the 2010 Haiti earthquake claimed only a few lives, in the 1530 El Pilar, Venezuela; 1602 Port Royale, Jamaica; 1918 Puerto Rico; and 1946 Samaná, Dominican Republic tsunamis the death tolls ranged to over a thousand. Since then, there has been an explosive increase in residents, visitors, infrastructure, and economic activity along the coastlines, increasing the potential for human and economic loss. It has been estimated that on any day, upwards of more than 500,000 people could be in harm's way just along the beaches, with hundreds of thousands more working and living in the tsunamis hazard zones. Given the relative infrequency of tsunamis, exercises are a valuable tool to test communications, evaluate preparedness and raise awareness. Exercises in the Caribbean are conducted under the framework of the UNESCO IOC Intergovernmental Coordination Group for the Tsunami and other Coastal Hazards Warning System for the Caribbean and Adjacent Regions (CARIBE EWS) and the US National Tsunami Hazard Mitigation Program. On March 23, 2011, 34 countries and territories participated in the first CARIBE WAVE/LANTEX regional tsunami exercise, while in the second exercise on March 20, 2013 a total of 45 countries and territories participated. 481 organizations (almost 200 more than in 2011) also registered to receive the bulletins issued by the Pacific Tsunami Warning Center (PTWC), West Coast and Alaska Tsunami Warning Center and/or the Puerto Rico

  1. Simulations of Tsunami Triggered by the 1883 Krakatau Volcanic Eruption: Implications for Tsunami Hazard in the South China Sea

    NASA Astrophysics Data System (ADS)

    Tan, Y.; Lin, J.

    2013-12-01

    The 1883 Krakatau eruption in Indonesia is one of the largest recorded volcanic eruptions in recent history. The associated tsunami claimed about 36,000 lives and recorded run-up heights up to 30 m along the coastal regions in the Sunda Straits between the Indian Ocean and the South China Sea. Our study aims to better understand the generation and propagation mechanisms of this volcano-induced tsunami through modeling quantitatively the tsunami triggering processes at the source region. Comparison of non-linear simulations using the Cornell Multi-grid Coupled Tsunami Model (COMCOT) with observations reveals that a donut-shape 'hole and ring' initial condition for the tsunami source is able to explain the key characteristics of the observed tsunami: A 'hole' of about 6 km in diameter and 270 m in depth corresponds to the collapse of the Krakatau volcano on August 27, 1883, while a 'ring' of uplift corresponds to the deposition of the erupted volcanic materials. We found that the shallowness and narrowness of the entrance pathway of the Sunda Straits limited the northward transfer of the tsunami energy from the source region into the South China Sea. Instead, the topographic and bathymetric characteristics favored the southward transfer of the energy into the Indian Ocean. This might explain why Sri Lanka and India suffered casualties from this event, while areas inside the South China Sea, such as Singapore, did not record significant tsunami signals. Modeling results further suggest that the shallow topography of the surrounding islands around the Krakatau source region might have contributed to a reduction in maximum run-up heights in the coastal regions of the Sunda Straits.

  2. Web-based Tsunami Early Warning System: a case study of the 2010 Kepulaunan Mentawai Earthquake and Tsunami

    NASA Astrophysics Data System (ADS)

    Ulutas, E.; Inan, A.; Annunziato, A.

    2012-06-01

    This study analyzes the response of the Global Disasters Alerts and Coordination System (GDACS) in relation to a case study: the Kepulaunan Mentawai earthquake and related tsunami, which occurred on 25 October 2010. The GDACS, developed by the European Commission Joint Research Center, combines existing web-based disaster information management systems with the aim to alert the international community in case of major disasters. The tsunami simulation system is an integral part of the GDACS. In more detail, the study aims to assess the tsunami hazard on the Mentawai and Sumatra coasts: the tsunami heights and arrival times have been estimated employing three propagation models based on the long wave theory. The analysis was performed in three stages: (1) pre-calculated simulations by using the tsunami scenario database for that region, used by the GDACS system to estimate the alert level; (2) near-real-time simulated tsunami forecasts, automatically performed by the GDACS system whenever a new earthquake is detected by the seismological data providers; and (3) post-event tsunami calculations using GCMT (Global Centroid Moment Tensor) fault mechanism solutions proposed by US Geological Survey (USGS) for this event. The GDACS system estimates the alert level based on the first type of calculations and on that basis sends alert messages to its users; the second type of calculations is available within 30-40 min after the notification of the event but does not change the estimated alert level. The third type of calculations is performed to improve the initial estimations and to have a better understanding of the extent of the possible damage. The automatic alert level for the earthquake was given between Green and Orange Alert, which, in the logic of GDACS, means no need or moderate need of international humanitarian assistance; however, the earthquake generated 3 to 9 m tsunami run-up along southwestern coasts of the Pagai Islands where 431 people died. The post

  3. Alaska earthquake source for the SAFRR tsunami scenario: Chapter B in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

    USGS Publications Warehouse

    Kirby, Stephen; Scholl, David; von Huene, Roland; Wells, Ray

    2013-01-01

    Tsunami modeling has shown that tsunami sources located along the Alaska Peninsula segment of the Aleutian-Alaska subduction zone have the greatest impacts on southern California shorelines by raising the highest tsunami waves for a given source seismic moment. The most probable sector for a Mw ~ 9 source within this subduction segment is between Kodiak Island and the Shumagin Islands in what we call the Semidi subduction sector; these bounds represent the southwestern limit of the 1964 Mw 9.2 Alaska earthquake rupture and the northeastern edge of the Shumagin sector that recent Global Positioning System (GPS) observations indicate is currently creeping. Geological and geophysical features in the Semidi sector that are thought to be relevant to the potential for large magnitude, long-rupture-runout interplate thrust earthquakes are remarkably similar to those in northeastern Japan, where the destructive Mw 9.1 tsunamigenic earthquake of 11 March 2011 occurred. In this report we propose and justify the selection of a tsunami source seaward of the Alaska Peninsula for use in the Tsunami Scenario that is part of the U.S. Geological Survey (USGS) Science Application for Risk Reduction (SAFRR) Project. This tsunami source should have the potential to raise damaging tsunami waves on the California coast, especially at the ports of Los Angeles and Long Beach. Accordingly, we have summarized and abstracted slip distribution from the source literature on the 2011 event, the best characterized for any subduction earthquake, and applied this synoptic slip distribution to the similar megathrust geometry of the Semidi sector. The resulting slip model has an average slip of 18.6 m and a moment magnitude of Mw = 9.1. The 2011 Tohoku earthquake was not anticipated, despite Japan having the best seismic and geodetic networks in the world and the best historical record in the world over the past 1,500 years. What was lacking was adequate paleogeologic data on prehistoric earthquakes

  4. The Big Splash: Tsunami from Large Asteroid and Comet Impacts

    NASA Astrophysics Data System (ADS)

    Hills, J.; Goda, M.

    Asteroid and comet impacts produce a large range of damage. Tsunami may produce most of the economic damage in large asteroid impacts. Large asteroid impacts produce worldwide darkness lasting several months that may kill more people by mass starvation, especially in developing countries, than would tsunami, but the dust should not severely affect economic infrastructure. The tsunami may even kill more people in developed countries with large coastal populations, such as the United States, than the starvation resulting from darkness. We have been determining which regions of Earth are most susceptible to asteroid tsunami by simulating the effect of a large asteroid impact into mid-ocean. We have modeled the effect of midAtlantic and midPacific impacts that produce craters 300 to 150 km in diameter. A KT-size impactor would cause the larger of these craters. We used a computer code that has successfully determined the runup and inundation from historical earthquake-generated tsunami. The code has been progressively improved to eliminate previous problems at the domain boundaries, so it now runs until the tsunami inundation is complete. We find that the larger of these two midAtlantic impacts would engulf the entire Florida Peninsula. The smaller one would inundate the eastern third of the peninsula while a tsunami passing through the Gulf of Cuba would inundate the West Coast of Florida. Impacts at three different sites in the Pacific show the great vulnerability of Tokyo and its surroundings to asteroid tsunami. Mainland Asia is relatively protected from asteroid tsunami. In Europe, the Iberian Peninsula and the Atlantic Providences of France are highly vulnerable to asteroid tsunami.

  5. 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

  6. Scientific Animations for Tsunami Hazard Mitigation: The Pacific Tsunami Warning Center's YouTube Channel

    NASA Astrophysics Data System (ADS)

    Becker, N. C.; Wang, D.; Shiro, B.; Ward, B.

    2013-12-01

    Outreach and education save lives, and the Pacific Tsunami Warning Center (PTWC) has a new tool--a YouTube Channel--to advance its mission to protect lives and property from dangerous tsunamis. Such outreach and education is critical for coastal populations nearest an earthquake since they may not get an official warning before a tsunami reaches them and will need to know what to do when they feel strong shaking. Those who live far enough away to receive useful official warnings and react to them, however, can also benefit from PTWC's education and outreach efforts. They can better understand a tsunami warning message when they receive one, can better understand the danger facing them, and can better anticipate how events will unfold while the warning is in effect. The same holds true for emergency managers, who have the authority to evacuate the public they serve, and for the news media, critical partners in disseminating tsunami hazard information. PTWC's YouTube channel supplements its formal outreach and education efforts by making its computer animations available 24/7 to anyone with an Internet connection. Though the YouTube channel is only a month old (as of August 2013), it should rapidly develop a large global audience since similar videos on PTWC's Facebook page have reached over 70,000 viewers during organized media events, while PTWC's official web page has received tens of millions of hits during damaging tsunamis. These animations are not mere cartoons but use scientific data and calculations to render graphical depictions of real-world phenomena as accurately as possible. This practice holds true whether the animation is a simple comparison of historic earthquake magnitudes or a complex simulation cycling through thousands of high-resolution data grids to render tsunami waves propagating across an entire ocean basin. PTWC's animations fall into two broad categories. The first group illustrates concepts about seismology and how it is critical to

  7. Incorporating Tsunami Projections to Sea Level Rise Vulnerability Assessments -A Case Study for Midway Atoll-

    NASA Astrophysics Data System (ADS)

    Gica, E.; Reynolds, M.

    2012-12-01

    Recent global models predict a rise of approximately one meter in global sea level by 2100, with potentially larger increases in areas of the Pacific Ocean. If current climate change trends continue, low-lying islands across the globe may become inundated over the next century, placing island biodiversity at risk. Adding to the risk of inundation due to sea level rise is the occurrence of cyclones and tsunamis. This combined trend will affect the low-lying islands of the Northwestern Hawaiian Islands and it is therefore important to assess its impact since these islands are critical habitats to many endangered endemic species and support the largest tropical seabird rookery in the world. The 11 March 2011 Tohoku (Mw=8.8) earthquake-tsunami affected the habitat of many endangered endemic species in Midway Atoll National Wildlife Refuge because all three islands (Sand, Eastern and Spit) were inundated by tsunami waves. At present sea level, some tsunamis from certain source regions would not affect Midway Atoll. For example, the previous earthquake-tsunamis such as the 15 November 2006 Kuril (Mw=8.1) and 13 February 2007 Kuril (Mw=7.9) were not significant enough to affect Midway Atoll. But at higher sea levels, tsunamis with similar characteristics could pose a threat to such terrestrial habitats and wildlife. To visualize projected impacts to vegetation composition, wildlife habitat, and wildlife populations, we explored and analyzed inundation vulnerability for a range of possible sea level rise and tsunami scenarios at Midway Atoll National Wildlife Refuge. Studying the combined threat of tsunamis and sea level rise can provide more accurate and comprehensive assessments of the vulnerability of the unique natural resources on low-lying islands. A passive sea level rise model was used to determine how much inundation will occur at different sea level rise values for the three islands of Midway Atoll and each scenario was coupled with NOAA Center for Tsunami

  8. Social 'meltdown' in the demise of an island endemic: Allee effects and the Vancouver Island marmot.

    PubMed

    Brashares, Justin S; Werner, Jeffery R; Sinclair, A R E

    2010-09-01

    1. More than 75 years have passed since W.C. Allee proposed that breakdowns in sociality may shift animal populations to inverse density dependence at small sizes and thereby hasten spirals to extinction. Despite decades of attention, empirical evidence of this 'Allee effect' in wild populations remains scarce. 2. Here, we report on findings from a multi-year study of the population ecology and behaviour of the critically endangered Vancouver Island marmot (Marmota vancouverensis) and present quantitative evidence of an Allee effect and highlight the mechanisms that drive it. 3. The V.I. marmot is a large, social rodent endemic to Vancouver Island, Canada, and its population has declined by 80-90% since the 1980s. The species currently is represented in the wild by roughly 200 individuals. 4. This study compared characteristics of contemporary V.I. marmots (2002-2005) with (i) animals in the same population at an earlier time period (1973-1975) and (ii) congeners. Specifically, data on time allocation, social activity and ranging behaviour of animals in colonies in the late stages of decline were compared with historical data collected from colonies under more stable demographic conditions. 5. We found that contemporary V.I. marmots had home ranges that were 10-60x larger than historic animals and congeners, interacted with conspecifics at 10% of the historic rate, devoted 10x more time to anti-predator vigilance, and abandoned the bi-modal activity patterns previously described for this and other marmot species. Contemporary marmots also showed an 86% decline in feeding rate, and entered hibernation on average 20 days later than animals in historic populations. 6. Combined with results showing reduced per capita survival and reproduction in contemporary marmots, these findings suggest a strong role for Allee effects in the current plight of the Vancouver Island marmot. A positive link between aspects of fitness and population size emphasizes the need to identify

  9. Tides and tsunamis

    NASA Technical Reports Server (NTRS)

    Zetler, B. D.

    1972-01-01

    Although tides and tsunamis are both shallow water waves, it does not follow that they are equally amenable to an observational program using an orbiting altimeter on a satellite. A numerical feasibility investigation using a hypothetical satellite orbit, real tide observations, and sequentially increased levels of white noise has been conducted to study the degradation of the tidal harmonic constants caused by adding noise to the tide data. Tsunami waves, possibly a foot high and one hundred miles long, must be measured in individual orbits, thus requiring high relative resolution.

  10. 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).

  11. Application of Seismic Array Processing to Tsunami Early Warning

    NASA Astrophysics Data System (ADS)

    An, C.; Meng, L.

    2015-12-01

    Tsunami wave predictions of the current tsunami warning systems rely on accurate earthquake source inversions of wave height data. They are of limited effectiveness for the near-field areas since the tsunami waves arrive before data are collected. Recent seismic and tsunami disasters have revealed the need for early warning to protect near-source coastal populations. In this work we developed the basis for a tsunami warning system based on rapid earthquake source characterisation through regional seismic array back-projections. We explored rapid earthquake source imaging using onshore dense seismic arrays located at regional distances on the order of 1000 km, which provides faster source images than conventional teleseismic back-projections. We implement this method in a simulated real-time environment, and analysed the 2011 Tohoku earthquake rupture with two clusters of Hi-net stations in Kyushu and Northern Hokkaido, and the 2014 Iquique event with the Earthscope USArray Transportable Array. The results yield reasonable estimates of rupture area, which is approximated by an ellipse and leads to the construction of simple slip models based on empirical scaling of the rupture area, seismic moment and average slip. The slip model is then used as the input of the tsunami simulation package COMCOT to predict the tsunami waves. In the example of the Tohoku event, the earthquake source model can be acquired within 6 minutes from the start of rupture and the simulation of tsunami waves takes less than 2 min, which could facilitate a timely tsunami warning. The predicted arrival time and wave amplitude reasonably fit observations. Based on this method, we propose to develop an automatic warning mechanism that provides rapid near-field warning for areas of high tsunami risk. The initial focus will be Japan, Pacific Northwest and Alaska, where dense seismic networks with the capability of real-time data telemetry and open data accessibility, such as the Japanese HiNet (>800

  12. The effects of island ontogeny on species diversity and phylogeny.

    PubMed

    Valente, Luis M; Etienne, Rampal S; Phillimore, Albert B

    2014-06-07

    A major goal of island biogeography is to understand how island communities are assembled over time. However, we know little about the influence of variable area and ecological opportunity on island biotas over geological timescales. Islands have limited life spans, and it has been posited that insular diversity patterns should rise and fall with an island's ontogeny. The potential of phylogenies to inform us of island ontogenetic stage remains unclear, as we lack a phylogenetic framework that focuses on islands rather than clades. Here, we present a parsimonious island-centric model that integrates phylogeny and ontogeny into island biogeography and can incorporate a negative feedback of diversity on species origination. This framework allows us to generate predictions about species richness and phylogenies on islands of different ages. We find that peak richness lags behind peak island area, and that endemic species age increases with island age on volcanic islands. When diversity negatively affects rates of immigration and cladogenesis, our model predicts speciation slowdowns on old islands. Importantly, we find that branching times of in situ radiations can be informative of an island's ontogenetic stage. This novel framework provides a quantitative means of uncovering processes responsible for island biogeography patterns using phylogenies.

  13. Tsunami hazards to U.S. coasts from giant earthquakes in Alaska

    USGS Publications Warehouse

    Ryan, Holly F.; von Huene, Roland; Scholl, Dave; Kirby, Stephen

    2012-01-01

    In the aftermath of Japan's devastating 11 March 2011Mw 9.0 Tohoku earthquake and tsunami, scientists are considering whether and how a similar tsunami could be generated along the Alaskan-Aleutian subduction zone (AASZ). A tsunami triggered by an earthquake along the AASZ would cross the Pacific Ocean and cause extensive damage along highly populated U.S. coasts, with ports being particularly vulnerable. For example, a tsunami in 1946 generated by a Mw 8.6 earthquake near Unimak Pass, Alaska (Figure 1a), caused significant damage along the U.S. West Coast, took 150 lives in Hawaii, and inundated shorelines of South Pacific islands and Antarctica [Fryer et al., 2004; Lopez and Okal, 2006]. The 1946 tsunami occurred before modern broadband seismometers were in place, and the mechanisms that created it remain poorly understood.

  14. Tsunami hazards to U.S. coasts from giant earthquakes in Alaska

    NASA Astrophysics Data System (ADS)

    Ryan, Holly; von Huene, Roland; Scholl, Dave; Kirby, Steve

    2012-05-01

    In the aftermath of Japan's devastating 11 March 2011Mw 9.0 Tohoku earthquake and tsunami, scientists are considering whether and how a similar tsunami could be generated along the Alaskan-Aleutian subduction zone (AASZ). A tsunami triggered by an earthquake along the AASZ would cross the Pacific Ocean and cause extensive damage along highly populated U.S. coasts, with ports being particularly vulnerable. For example, a tsunami in 1946 generated by a Mw 8.6 earthquake near Unimak Pass, Alaska (Figure 1a), caused signifcant damage along the U.S. West Coast, took 150 lives in Hawaii, and inundated shorelines of South Pacific islands and Antarctica [Fryer et al., 2004; Lopez and Okal, 2006]. The 1946 tsunami occurred before modern broadband seismometers were in place, and the mechanisms that created it remain poorly understood.

  15. Did the Mentawai 2010 earthquake produce an ionospheric tsunami that would have helped identify it as a rare tsunami earthquake?

    NASA Astrophysics Data System (ADS)

    Manta, Fabio; Hill, Emma M.; Occhipinti, Giovanni; Feng, Lujia; Taisne, Benoit

    2016-04-01

    On October 25th 2010, an earthquake of Mw 7.8 was generated by rupture of the shallow portion of the Sunda megathrust seaward of the Mentawai islands, Sumatra, Indonesia. The maximum tsunami run-up was ~16 m (Hill et al., 2012) along the southwestern coasts of the Pagai Islands; the tsunami claimed >400 lives. Previously, on April 2010, a similar magnitude earthquake (also Mw 7.8) occurred near the Banyak Islands, offshore northern Sumatra. This event, however, did not generate a tsunami and caused only minor damages. The main difference between these two events is related to the location of the rupture on the megathrust: for the 2010 Banyaks event it was too deep, and located under the islands, to generate significant uplift of the seafloor; on the other hand, the 2010 Mentawai event ruptured a very shallow portion of the megathrust and resulted in large uplifts of the seafloor. The Mentawai event generated only mild, long-period seismic shaking, and (due to its distance) from the stations, relatively small GPS displacements, and its moderate magnitude meant that it was not immediately identified being capable of generating an outsize tsunami. Did these two events induce gravity waves in the ionosphere that would have been useful to identify the Mentawai event as a tsunami earthquake? In this work, we analyzed the ionospheric responses to both events to look for the presence and magnitude of induced travel ionosphere disturbances (TIDs) in the ionosphere total electron content (TEC). Our results show that the Mentawai earthquake induced waves in the ionosphere that start ~8 minutes after the mainshock and propagate with the velocity of acoustic waves (~1 km/sec). Contrarily, the Banyaks earthquake did not produce any recognizable signature in the ionospheric TEC. Our results suggest that the important differences in the style of the two earthquakes can be detected by monitoring variations in the ionospheric TEC.

  16. The destructive 1946 Unimak near-field tsunami: New evidence for a submarine slide source from reprocessed marine geophysical data

    NASA Astrophysics Data System (ADS)

    Huene, Roland; Kirby, Stephen; Miller, John; Dartnell, Peter

    2014-10-01

    The Mw 8.6 earthquake in 1946 off the Pacific shore of Unimak Island at the end of the Alaska Peninsula generated a far-field tsunami that crossed the Pacific to Antarctica. Its tsunami magnitude, 9.3, is comparable to the 9.1 magnitude of the 2011 Tohoku tsunami. On Unimak Island's Pacific shore, a runup of 42 m destroyed the lighthouse at Scotch Cap. Elsewhere, localized tsunamis with such high runups have been interpreted as caused by large submarine landslides. However, previous to this study, no landslide large enough to generate this runup was found in the area that is limited by the time interval between earthquake shaking and tsunami inundation at Scotch Cap. Reworking of a seismic reflection transect and colocated multibeam bathymetric surveys reveal a landslide block that may explain the 1946 high runup. It is seaward of Scotch Cap on the midslope terrace and within the time-limited area.

  17. The destructive 1946 Unimak near-field tsunami: New evidence for a submarine slide source from reprocessed marine geophysical data

    USGS Publications Warehouse

    von Huene, Roland; Kirby, Stephen; Miller, John J.; Dartnell, Peter

    2014-01-01

    The Mw 8.6 earthquake in 1946 off the Pacific shore of Unimak Island at the end of the Alaska Peninsula generated a far-field tsunami that crossed the Pacific to Antarctica. Its tsunami magnitude, 9.3, is comparable to the 9.1 magnitude of the 2011 Tohoku tsunami. On Unimak Island's Pacific shore, a runup of 42 m destroyed the lighthouse at Scotch Cap. Elsewhere, localized tsunamis with such high runups have been interpreted as caused by large submarine landslides. However, previous to this study, no landslide large enough to generate this runup was found in the area that is limited by the time interval between earthquake shaking and tsunami inundation at Scotch Cap. Reworking of a seismic reflection transect and colocated multibeam bathymetric surveys reveal a landslide block that may explain the 1946 high runup. It is seaward of Scotch Cap on the midslope terrace and within the time-limited area.

  18. Observations of the 2011 Tohoku Tsunami on the Coast of British Columbia

    NASA Astrophysics Data System (ADS)

    Rabinovich, A.; Thomson, R.

    2014-12-01

    The Great Tohoku Earthquake (Mw 9.0) of 11 March 2011 generated highly catastrophic tsunami waves that reached runup heights of up to 40 m along the coast of Japan and were recorded by numerous coastal tide gauges and bottom pressure stations throughout the Pacific Ocean. Near the coast of British Columbia (BC), the tsunami was measured by 15 permanent tide gauges, including gauges located well inside the Strait of Georgia and at Patricia Bay in Saanich Inlet (the site of the Institute of Ocean Sciences, IOS). Tsunami waves were also recorded by 5 temporary tide gauges within Victoria Harbour waterways (Gorge and Portage inlets), by 4 NEPTUNE-Canada bottom cable observatories on the Vancouver Island shelf and by 3 VENUS bottom pressure recorders within Saanich Inlet. Maximum tsunami wave heights observed on the outer BC coast were 1.0-1.5 m, while those within the sheltered basins of the inner coast were about ten times lower. The tsunami wave signal was also observed in the temperature, salinity and current velocity records of CTDs and an ADCP installed in an anoxic Canadian fjord on the coast of Vancouver Island. The collected data enabled us to examine the statistical and spectral properties of the 2011 Tohoku tsunami on the coast of British Columbia and to estimate the relative tsunami risk for this coast from distant earthquakes. The tsunami record from the deepest NEPTUNE (CORK) station was used as the input function for the IOS regional tsunami forecast model. The computed and observed tsunami wave forms for this event were in good agreement.

  19. Alternative Tsunami Models

    ERIC Educational Resources Information Center

    Tan, A.; Lyatskaya, I.

    2009-01-01

    The interesting papers by Margaritondo (2005 "Eur. J. Phys." 26 401) and by Helene and Yamashita (2006 "Eur. J. Phys." 27 855) analysed the great Indian Ocean tsunami of 2004 using a simple one-dimensional canal wave model, which was appropriate for undergraduate students in physics and related fields of discipline. In this paper, two additional,…

  20. Evidence for a Mega-Tsunami Generated by Giant Flank Collapse of Fogo Volcano, Cape Verde

    NASA Astrophysics Data System (ADS)

    Ramalho, R. S.; Madeira, J.; Helffrich, G. R.; Schaefer, J. M.; Winckler, G.; Quartau, R.; Adena, K.

    2013-12-01

    Mega-tsunamis generated by ocean island flank collapses are expected to be some of the most hazardous forces of nature, yet evidence for their near-source effects and inferred high run-ups so far is scarce or hotly debated. A newly discovered deposit on the northern coast of Santiago Island (Cape Verde), however, documents the magnitude and run-up height associated with this kind of event. Additionally to chaotic conglomerates distributed from sea-level up to 100 m elevation standing on slopes as steep as 20°, the deposit comprises a number of scattered megaclasts of submarine lava flows, limestone and tuff. The megaclasts are presently located over a higher substructural slope built on younger subaerial lava flows and at elevations ranging 160-220 m a.s.l. All megaclasts correspond to lithologies that crop out exclusively in nearby cliff faces. The origin of this deposit is consequently attributed to an exceptional wave that plucked blocks from the cliff face, transported them inland and deposited them over the higher slopes of the volcanic edifice. The distribution of the megaclasts, together with the local geomorphology, is in agreement with a tsunami that approached the island edifice from the west and was refracted along its northern flank, flooding a series of northwest-oriented valleys. This suggests that the well-known flank collapse of Fogo volcano, located 55 km west of Santiago, is the most likely source, a hypothesis being tested with surface exposure dating. The inferred run-up exceeded 200 m and is consistent with numerical simulations by Paris et al. 2011, implying that the present Fogo island morphology probably developed by at least one giant flank collapse with devastating near-source effects.

  1. Tsunami-Relief Groups Advise K-12

    ERIC Educational Resources Information Center

    Hurst, Marianne D.

    2005-01-01

    As American schools pitch in with an array of charitable projects in response to the tsunami in South Asia, experts say educators and students should consider carefully how they can most effectively support relief groups, avoid fund-raising scams, and incorporate their efforts into service-learning programs. When students returned to school after…

  2. Forecasting Wave Amplitudes after the Arrival of a Tsunami

    NASA Astrophysics Data System (ADS)

    Nyland, David; Huang, Paul

    2014-12-01

    The destructive Pacific Ocean tsunami generated off the east coast of Honshu, Japan, on 11 March 2011 prompted the West Coast and Alaska Tsunami Warning Center (WCATWC) to issue a tsunami warning and advisory for the coastal regions of Alaska, British Columbia, Washington, Oregon, and California. Estimating the length of time the warning or advisory would remain in effect proved difficult. To address this problem, the WCATWC developed a technique to estimate the amplitude decay of a tsunami recorded at tide stations within the Warning Center's Area of Responsibly (AOR). At many sites along the West Coast of North America, the tsunami wave amplitudes will decay exponentially following the arrival of the maximum wave ( Mofjeld et al., Nat Hazards 22:71-89, 2000). To estimate the time it will take before wave amplitudes drop to safe levels, the real-time tide gauge data are filtered to remove the effects of tidal variations. The analytic envelope is computed and a 2 h sequence of amplitude values following the tsunami peak is used to obtain a least squares fit to an exponential function. This yields a decay curve which is then combined with an average West Coast decay function to provide an initial tsunami amplitude-duration forecast. This information may then be provided to emergency managers to assist with response planning.

  3. The Redwood Coast Tsunami Work Group: a unique organization promoting earthquake and tsunami resilience on California's North Coast

    NASA Astrophysics Data System (ADS)

    Dengler, L.; Henderson, C.; Larkin, D.; Nicolini, T.; Ozaki, V.

    2012-12-01

    The Northern California counties of Del Norte, Humboldt, and Mendocino account for over 30% of California's coastline and is one of the most seismically active areas of the contiguous 48 states. The region is at risk from earthquakes located on- and offshore and from tsunamis generated locally from faults associated with the Cascadia subduction zone (CSZ) and from distant sources elsewhere in the Pacific. In 1995 the California Geological Survey (CGS) published a scenario for a CSZ earthquake that included both strong ground shaking effects and a tsunami. As a result of the scenario, the Redwood Coast Tsunami Work Group (RCTWG), an organization of government agencies, tribes, service groups, academia and the private sector, was formed to coordinate and promote earthquake and tsunami hazard awareness and mitigation in the three-county region. The RCTWG and its member agencies projects include education/outreach products and programs, tsunami hazard mapping, signage and siren planning. Since 2008, RCTWG has worked with the California Emergency Management Agency (Cal EMA) in conducting tsunami warning communications tests on the North Coast. In 2007, RCTWG members helped develop and carry out the first tsunami training exercise at FEMA's Emergency Management Institute in Emmitsburg, MD. The RCTWG has facilitated numerous multi-agency, multi-discipline coordinated exercises, and RCTWG county tsunami<