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Sample records for island tsunami effects

  1. The Flores Island tsunamis

    NASA Astrophysics Data System (ADS)

    Yeh, Harry; Imamura, Fumihiko; Synolakis, Costas; Tsuji, Yoshinobu; Liu, Philip; Shi, Shaozhong

    On December 12, 1992, at 5:30 A.M. GMT, an earthquake of magnitude Ms 7.5 struck the eastern region of Flores Island, Indonesia (Figure 1), a volcanic island located just at the transition between the Sunda and Banda Island arc systems. The local newspaper reported that 25-m high tsunamis struck the town of Maumere, causing substantial casualties and property damage. On December 16, television reports broadcast in Japan via satellite reported that 1000 people had been killed in Maumere and twothirds of the population of Babi Island had been swept away by the tsunamis.The current toll of the Flores earthquake is 2080 deaths and 2144 injuries, approximately 50% of which are attributed to the tsunamis. A tsunami survey plan was initiated within 3 days of the earthquake, and a cooperative international survey team was formed with four scientists from Indonesia, nine from Japan, three from the United States, one from the United Kingdom, and one from Korea.

  2. 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.

  3. The role of diffraction effects in extreme runup inundation at Okushiri Island due to 1993 tsunami

    NASA Astrophysics Data System (ADS)

    Kim, K. O.; Kim, D. C.; Choi, B. H.; Jung, K. T.; Yuk, J. H.; Pelinovsky, E.

    2014-11-01

    The tsunami generated on 12 July 1993 by Hokkaido-Nansei-Oki earthquake (Mw = 7.8) has brought about the maximum wave run-up of 31.7 m, the highest record in Japan of 20th century, near the Monai Valley on the west coast of the Okushiri island (Hokkaido Tsunami Survey Group, 1993). To reproduce the extreme run-up height the three-dimensional non-hydrostatic model (Flow Science, 2012) denoted by NH-model has been locally applied with open boundary conditions supplied in an offline manner by the three-dimensional hydrostatic model (Ribeiro et al., 2011) denoted by H-model which is sufficiently large to cover the entire fault region with one-way nested multiple domains. For the initial water deformation Okada's fault model (1985) using the 3 sub-fault parameters is applied. Three non-hydrostatic model experiments have been performed, namely experiment without island, with one island and with two islands. The experiments with one island and with two islands give rise to values close to the observation with maximum run-up heights of about 32.3 and 30.8 m, respectively, while the experiment without islands gives rise to about 25.2 m. The diffraction of tsunami wave primarily by Muen Island located at the South and the southward topographic guiding of tsunami run-up at the coast are as in the laboratory simulation (Yoneyama et al., 2002) found to result in the extreme run-up height near the Monai Valley. The presence of Hira Island enhances the diffraction of tsunami waves but its contribution to the extreme run-up height is marginal.

  4. Solomon Islands Tsunami, One Year Later

    NASA Astrophysics Data System (ADS)

    McAdoo, Brian G.; Fritz, Hermann; Jackson, Kelly L.; Kalligeris, Nikos; Kruger, Jens; Bonte-Grapentin, Michael; Moore, Andrew L.; Rafiau, Wilson B.; Billy, Douglas; Tiano, Braddley

    2008-04-01

    The geologic and economic effects of the 2 April 2007 Solomon Islands earthquake and tsunami are distinctly visible a little more than a year after the event. Coral reef colonies that were sheared off and uplifted are slowly recovering, and many new earthquake-triggered landslides remain mobile. Large volumes of sediment created by the earthquake and mobilized by the tsunami have been flushed from the lagoons between the reef and shoreline into deeper water, although significant quantities remain on land. Sediment from the lagoons covers piles of shattered coral that the tsunami moved from the lagoons to the base of channels in the barrier reef. These shattered corals have a higher chance of preservation as paleotsunami deposits than the material deposited on land.

  5. In Brief: Tsunami hits the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2007-04-01

    A magnitude 8.1 earthquake shook the Solomon Islands on 1 April at approximately 7:40 A.M. local time. The earthquake generated a tsunami several meters high that struck many of the islands. The earthquake occurred along the boundary of the Pacific plate where the Australia, Woodlark, and Solomon Sea plates subduct beneath it, according to the U.S. Geological Survey's Earthquake Hazards Program. At least 34 people were killed by the tsunami and several dozen more are still missing, according to the National Disaster Council in the Solomon Islands. The NDC estimates that 900-2500 homes were destroyed by the tsunami, displacing about 5500 people.

  6. 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).

  7. Health Effects of Tsunamis

    MedlinePlus

    ... on Specific Types of Emergencies Health Effects of Tsunamis Language: English Español (Spanish) Recommend on Facebook Tweet ... environmental hazards. The majority of deaths associated with tsunamis are related to drownings, but traumatic injuries are ...

  8. 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.

  9. The role of diffraction effects in extreme run-up inundation at Okushiri Island due to 1993 tsunami

    NASA Astrophysics Data System (ADS)

    Kim, K. O.; Kim, D. C.; Choi, B. H.; Jung, K. T.; Yuk, J. H.; Pelinovsky, E.

    2015-04-01

    The tsunami generated on 12 July 1993 by the Hokkaido-Nansei-Oki earthquake (Mw = 7.8) brought about a maximum wave run-up of 31.7 m, the highest recorded in Japan during the 20th century, near the Monai Valley on the west coast of Okushiri Island (Hokkaido Tsunami Survey Group, 1993). To reproduce the extreme run-up height, the three-dimensional non-hydrostatic model (Flow Science, 2012), referred to here as the NH-model, has been locally applied with open boundary conditions supplied in an offline manner by the three-dimensional hydrostatic model (Ribeiro et al., 2011), referred to here as the H-model. The area of the H-model is sufficiently large to cover the entire fault region with one-way nested multiple domains. For the initial water deformation, Okada's fault model (1985) using the sub-fault parameters is applied. Three NH-model experiments have been performed, namely without islands, with one island and with two islands. The experiments with one island and with two islands give rise to values close to the observation with maximum run-up heights of about 32.3 and 30.8 m, respectively, while the experiment without islands gives rise to about 25.2 m. The diffraction of the tsunami wave primarily by Muen Island, located in the south, and the southward topographic guiding of the tsunami run-up at the coast are, as in the laboratory simulation (Yoneyama et al., 2002), found to result in the extreme run-up height near Monai Valley. The presence of Hira Island enhances the diffraction of tsunami waves but its contribution to the extreme run-up height is marginal.

  10. 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.

  11. 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.

  12. Comparison of the 2010 and 2007 Solomon Island Tsunamis

    NASA Astrophysics Data System (ADS)

    Kalligeris, N.; Fritz, H.; Newman, A. V.; Feng, L.; Lifton, Z. M.; Wei, Y.; Titov, V. V.; Uslu, B. U.

    2010-12-01

    The 3 January 2010 Mw 7.1 earthquake off Rendova and Tetepare Islands, Western Province, Solomon Islands, generated surprisingly large tsunami waves, completely destroying Retavo village at Rendova Island’s south shore, located approximately 15 km from the trench. A reconnaissance team was deployed within a week, measuring local tsunami heights, maximum tsunami runup/inundation, coastal subsidence, co-seismic offset and afterslip, and interviewed eyewitnesses per established methods. This event occurred three years after the 1 April 2007 Mw 8.1 megathrust earthquake that generated a wide-spread tsunami across the Western Province Islands, causing 52 human casualties (Fritz and Kalligeris 2008). Although much smaller in magnitude than the 2007 event (below the assumed tsunamigenic magnitude threshold of ~Mw 7.5), the 2010 event produced a larger localized flow depth, and only moderately smaller runup, reaching a maximum value of 7 m on the southern shore of Rendova Isl. Observations of widespread subsidence on the south coasts of Rendova and Tetepare Islands ruled out the most probable shallow-dipping megathrust model of earthquake rupture. Instead, a high-angle conjugate intraslab thrust within the down going plate is preferred, agreeing with the seismically defined moment tensor, the observed coseismic subsidence, and enhanced tsunami excitation. The two events showed that SI population is very aware of its vulnerability to tsunamis, which we attribute to ancestral tsunami knowledge. Similar observations were made in Chile this year, where residents in most areas self-evacuated, significantly containing human casualties. We will compare the two Solomon Island events, in terms of our field findings, the source deformation models that best fit the observations, and present preliminary tsunami modeling results. Inundation in Tapurai village, Simbo Island in 2007 (left), and in Retavo village, Rendova Island in 2010 (right).

  13. 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.

  14. Tsunami Hazard in Crescent City, California from Kuril Islands earthquakes

    NASA Astrophysics Data System (ADS)

    Dengler, L.; Uslu, B.; Barberopoulou, A.

    2007-12-01

    On November 15, Crescent City in Del Norte County, California was hit by a series of tsunami surges generated by the M = 8.3 Kuril Islands earthquake causing an estimated 9.7 million (US dollars) in damages to the small boat basin. This was the first significant tsunami loss on US territory since the 1964 Alaska tsunami. The damage occurred nearly 8 hours after the official tsunami alert bulletins had been cancelled. The tsunami caused no flooding and did not exceed the ambient high tide level. All of the damage was caused by strong currents, estimated at 12 to 15 knots, causing the floating docks to be pinned against the pilings and water to flow over them. The event highlighted problems in warning criteria and communications for a marginal event with the potential for only localized impacts, the vulnerability of harbors from a relatively modest tsunami, and the particular exposure of the Crescent City harbor area to tsunamis. It also illustrated the poor understanding of local officials of the duration of tsunami hazard. As a result of the November tsunami, interim changes were made by WCATWC to address localized hazards in areas like Crescent City. On January 13, 2007 when a M = 8.1 earthquake occurred in the Kuril Islands, a formal procedure was in place for hourly conference calls between WCATWC, California State Office of Emergency Services officials, local weather Service Offices and local emergency officials, significantly improving the decision making process and the communication among the federal, state and local officials. Kuril Island tsunamis are relatively common at Crescent City. Since 1963, five tsunamis generated by Kuril Island earthquakes have been recorded on the Crescent City tide gauge, two with amplitudes greater than 0.5 m. We use the MOST model to simulate the 2006, 2007 and 1994 events and to examine the difference between damaging and non-damaging events at Crescent City. Small changes in the angle of the rupture zone results can result

  15. The potential failure of Monte Nuovo at Ischia Island (Southern Italy): numerical assessment of a likely induced tsunami and its effects on a densely inhabited area

    NASA Astrophysics Data System (ADS)

    Zaniboni, F.; Pagnoni, G.; Tinti, S.; Della Seta, M.; Fredi, P.; Marotta, E.; Orsi, G.

    2013-11-01

    Ischia is the emergent top of a large volcanic complex that rises more than 1,000 m above the sea floor, at the north-western end of the Gulf of Naples. Caldera resurgence in the central part of the island has resulted in the formation of differentially displaced blocks, among which Mt. Epomeo (787 m a.s.l.) is the most uplifted. Deformation and slope instability have been recognised as common features induced by a block resurgence mechanism that causes uplift and favours gravitational loading and flank failure. The Monte Nuovo block, a topographic high on the north-western flank of Mt. Epomeo, has recently been interpreted as a block affected by deep-seated gravitational slope deformation. This block may undergo a catastrophic failure in the case of renewal of magmatic activity. This paper investigates the potential failure of the Monte Nuovo block as a rockslide-debris avalanche, the consequent tsunami generation and wave propagation, and discusses the catastrophic effects of such an event. Mobilization-prone volume has been estimated at about 160·106 m3 and would move from a maximum elevation of 400 m a.s.l. The landslide itself would sweep away a densely populated territory as large as 3.5 km2. The highest waves generated by the tsunami, on which this paper is mainly focussed, would hit the northern and western shores of Ischia. However, the high coast would prevent inundation and limit devastation to beaches, harbours and surrounding areas. Most of the tsunami energy would head towards the north-east, hitting the Campania coast. Severe inundation would affect an area of up to 20 km2 around the mouth of the Volturno river, including the urban area of Castel Volturno. In contrast, less energy would travel towards the south, and the Gulf of Naples would be perturbed by long persisting waves of limited damaging potential.

  16. 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

  17. Tsunami Observations on Hydrophones and Island Seismic Stations

    NASA Astrophysics Data System (ADS)

    Hanson, J. A.; Bowman, J. R.; Reasoner, C. L.; Shields, G.

    2007-12-01

    The tsunami generated by the great Indonesian earthquake of 26 December 2004 was recorded across a myriad of technologies, many of which had not been designed, nor expected, to record tsunami signals. We reported on the tsunami signals from this event observed at hydrophones, intended for nuclear test monitoring, and broadband seismometers that are part of the global seismic network (GSN). Our observations led us to examine more recently reported tsunamis and other historic tsunamis. The great Sumatra-Andaman earthquake (Mw 9.1) produced high-frequency (greater than 5 mHz) dispersed tsunami signals, in addition to the destructive wave, recorded by hydrophone stations offshore from Diego Garcia and Cape Leeuwin, Australia, and by many seismic stations in the Indian Ocean and on the coast of Antarctica. Dispersed energy was observed to 60 mHz. The details within the dispersed signal provided source information to which tide gauge data are insensitive. The source of high-frequency signals could be determined using event- to-station distances estimated from the dispersion. Fine structure in the tsunami signal indicated a possible secondary high-frequency source. The dispersion observations and modeling also identified individual reflector sources over basin-wide distances. Two other recent tsunamis were observed in the Indian Ocean. The 28 March 2005 earthquake (Mw 8.6) produced high-frequency tsunami waves (to 20 mHz) observed at the Diego Garcia hydrophone station and the AIS seismic station. In addition, the lower frequency, non-dispersed tsunami waves were seen at four other seismic stations. The Mw 7.7 earthquake on 17 July 2006 south of Java also generated high frequency tsunami waves (to 10 mHz). Clear, dispersed signals were observed on hydrophone stations and seismic stations at the Cocos-Keeling Islands, and Casey, Antarctica. The first arriving energy is consistent with a source located at the earthquake epicenter. However, the strongest signals at Cocos

  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. Display of historical and hypothetical tsunami on the coast of Sakhalin Island

    NASA Astrophysics Data System (ADS)

    Kostenko, Irina; Zaytsev, Andrey; Kurkin, Andrey; Yalciner, Ahmet

    2014-05-01

    Tsunami waves achieve the coast of the Sakhalin Island and their sources are located in the Japan Sea, in the Okhotsk Sea, in Kuril Islands region and in the Pacific Ocean. Study of tsunami generation characteristics and its propagation allows studying display of the tsunami on the various parts of the island coast. For this purpose the series of computational experiments of some historical tsunamis was carried out. Their sources located in Japan Sea and Kuril Islands region. The simulation results are compared with the observations. Analysis of all recorded historical tsunami on coast of Sakhalin Island was done. To identify the possible display of the tsunami on the coast of Sakhalin Island the series of computational experiments of hypothetical tsunamis was carried out. Their sources located in the Japan Sea and in the Okhotsk Sea. There were used hydrodynamic sources. There were used different parameters of sources (length, width, height, raising and lowering of sea level), which correspond to earthquakes of various magnitudes. The analysis of the results was carried out. Pictures of the distribution of maximum amplitudes from each tsunami were done. Areas of Okhotsk Sea, Japan Sea and offshore strip of Sakhalin Island with maximum tsunami amplitudes were defined. Graphs of the distribution of maximum tsunami wave heights along the coast of the Sakhalin Island were plotted. Based on shallow-water equation tsunami numerical code NAMI DANCE was used for numerical simulations. This work was supported by ASTARTE project.

  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. PMID:26886197

  1. 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

  2. Tsunami-induced magnetic fields detected at Chichijima Island before the arrival of the 2011 Tohoku earthquake tsunami

    NASA Astrophysics Data System (ADS)

    Tatehata, Hidee; Ichihara, Hiroshi; Hamano, Yozo

    2015-11-01

    Magnetic field disturbances associated with the tsunami caused by the 2011 Tohoku earthquake were observed at Chichijima Island, 1200 km south of the epicenter. The vertical component of the magnetic field showed a periodic signal at approximately 20 min before the tsunami arrived. This study investigated the mechanism of the magnetic field signal using simulation studies. First, we derived a tsunami source model that explained the tide gauge records and sea-level changes at Chichijima Island. Using this model, we then computed the electric current induced by the tsunami and the resulting secondary magnetic field. The computed changes in sea level and magnetic field are consistent with their respective observed waveforms, including the timing of the magnetic field signals. In our interpretation, the tsunami flow induced an electric current along the tsunami wave front, which in turn generated a secondary induced magnetic field ahead of the tsunami wave. Hence, magnetic variations preceding the tsunami were observed at Chichijima Island. This suggests that imminent arrivals of tsunamis can be detected by observations of the magnetic field.

  3. 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

  4. Tsunami Deposits beneath Tidal Marshes on Northwestern Vancouver Island, British Columbia

    NASA Astrophysics Data System (ADS)

    Benson, Boyd E.; Grimm, Kurt A.; Clague, John J.

    1997-09-01

    Two sand sheets underlying tidal marshes at Fair Harbour, Neroutsos Inlet, and Koprino Harbour on the northwestern coast of Vancouver Island, British Columbia, were probably deposited by tsunamis. The sand sheets become thinner and finer-grained landward, drape former land surfaces, contain marine microfossils, are locally graded or internally stratified, and can be correlated with earthquakes that generated tsunamis in the region. 137Cs dating and historical accounts indicate that the upper sand sheet was deposited by the tsunami from the great Alaska earthquake in 1964. Radiocarbon ages on plant fossils within and on top of the lower sand sheet show that it was deposited sometime after about A.D. 1660. We attribute the lower sand sheet to a tsunami from the most recent plate-boundary earthquake on the Cascadia subduction zone about 300 yr ago, extending the documented effects of this earthquake north of the Nootka fault zone. The 1964 tsunami deposits differ little in thickness and continuity among the three marshes. In contrast, the lower sand sheet becomes thinner and less continuous to the north, implying a tsunami source south of the study area.

  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. Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Lynett, Patrick; Weiss, Robert; Renteria, Willington; De La Torre Morales, Giorgio; Son, Sangyoung; Arcos, Maria Elizabeth Martin; MacInnes, Breanyn Tiel

    2013-06-01

    On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the Mw 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the archipelago; (from west to east) Isabela, Santiagio, Santa Cruz, and San Cristobal. Access to the tsunami affected areas was one of the largest challenges of the field survey. Aside from approximately ten sandy beaches open to tourists, all other shoreline locations are restricted to anyone without a research permit; open cooperation with the Galapagos National Park provided the survey team complete access to the Islands coastlines. Survey locations were guided by numerical simulations of the tsunami performed prior to the field work. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum tsunami heights were generally in the range of 3-4 m with the highest runup of 6 m measured in a small pocket beach on Isla Isabela. Puerto Ayora, on Santa Cruz Island, the largest harbor in the Galapagos experienced significant flooding and damage to structures located at the shoreline. A current meter moored inside the harbor recorded relatively weak tsunami currents of less than 0.3 m/s (0.6 knot) during the event. Comparisons with detailed numerical simulations suggest that these low current speed observations are most likely the result of data averaging at 20-min intervals and that maximum instantaneous current speeds were considerably larger. Currents in the Canal de Itabaca, a natural waterway between Santa Cruz Island and a smaller island offshore, were strong enough to displace multiple 5

  7. Source Models and Near-Field Impact of the 1 April 2007 Solomon Islands Tsunami

    NASA Astrophysics Data System (ADS)

    Wei, Yong; Fritz, Hermann M.; Titov, Vasily V.; Uslu, Burak; Chamberlin, Chris; Kalligeris, Nikos

    2015-03-01

    Within weeks of the Solomon Islands earthquake of 1 April 2007, international tsunami survey teams discovered important biomarkers of crust rupture and tsunami heights along the islands' coastlines. Deep-ocean tsunameters recorded the tsunami waves of this event, enabling a real-time inversion of the tsunami source and model evaluation of near-field tsunami impact. The survey measurements provide valuable datasets for further confirmation of the tsunami source of the 1 April 2007 Solomon earthquake. These survey results also aided investigation of the correlation between sources determined by use of tsunameter records and those derived from seismometer records or crust-rupture measurements. In this study, to assess the near-field tsunami impact, we developed tsunami inundation models for the Solomon Islands, including tsunami waveforms, co-seismic land-level changes, and tsunami height distributions on individual islands. Compared with seismic-derived tsunami sources, modeling results based on the tsunameter-derived tsunami sources were a good match with field survey measurements. These results highlight the accuracy and efficiency of the tsunameter-derived tsunami source in modeling the near-field tsunami impact along a complex archipelago. We show that the source models, although derived by use of different methods, are all suited to initiation of inundation models developed for Solomon Islands. As these source models become available in real time or near real time, they can be implemented immediately in the inundation models to provide rapid guidance on tsunami hazard assessment, focused search and rescue operations, and post-event recovery and reconstruction.

  8. 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)

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  10. 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.

  11. 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.

  12. Including Tidal Effects in Tsunami Forecasting

    NASA Astrophysics Data System (ADS)

    Arcas, D.; Moore, C. W.; Spillane, M. C.; Bernard, E. N.

    2014-12-01

    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 interaction of tsunamis with a longer period water level variation due to tidal forcing, by comparing simulations of the 2011 Japan event at different at different locations with and without tidal effects. Our results demonstrate that while non-linear effects resulting from this interaction are minimal in water surface elevation, they can have a significant effect on inundation areas. Based on these findings we propose a simple, first-order correction to the standard MHW forecast, that can be performed on-the-fly by the SIFT system without the need for complex tidal models.

  13. Tsunami Field Survey for the Solomon Islands Earthquake of April 1, 2007

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Tanioka, Y.; Nakamura, Y.; Tsuji, Y.; Namegaya, Y.; Murata, M.; Woodward, S.

    2007-12-01

    Two weeks after the 2007 off-Solomon earthquake, an international tsunami survey team (ITST) of Japanese and US researchers performed a post tsunami survey in Ghizo and adjacent islands. Main purpose of the team was to provide information on the earthquake and tsunami to the national disaster council of the Solomon Islands, who was responsible for the disaster management at that time. The ITST had interview with the affected people and conducted reconnaissance mapping of the tsunami heights and flow directions. Tsunami flow heights at beach and inland were evaluated from watermarks on buildings and the position of broken branches and stuck materials on trees. These tsunami heights along the southern to western coasts of Ghizo Island were ca. 5m (a.s.l.). Tsunami run-up was traced by distribution of floating debris that carried up by the tsunami and deposited at their inundation limit. The maximum run-up was measured at Tapurai of Simbo Island to be ca. 9 m. Most of the inundation area was covered by 0-10 cm thick tsunami deposit that consists of beach sand, coral peaces and eroded soil. Coseismic uplift and subsidence were clearly identified by changes of the sea level before and after the earthquake, that were inferred by eyewitness accounts and evidences such as dried up coral reeves. These deformation patterns, as well as the tsunami height distribution, could constrain the earthquake fault geometry and motion. It is worthy of mention that the tsunami damage in villages in Ranongga Island has significantly reduced by 2-3 m uplift before the tsunami attack.

  14. 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

  15. Tsunami, post-tsunami malaria situation in Nancowry group of islands, Nicobar district, Andaman and Nicobar Islands

    PubMed Central

    Manimunda, Sathya Prakash; Sugunan, Attayoor Purushottaman; Sha, Wajid Ali; Singh, Shiv Shankar; Shriram, Ananganallur Nagarajan; Vijayachari, Paluru

    2011-01-01

    Background & objectives: Due to tsunami in 2004 a large proportion of population in Nicobar group of Islands become homeless, and in 2006 large scale labour migration took place to construct the houses. In 2008, a significant increase in malaria incidence was observed in this area. Therefore, in March 2008, the situation of malaria was assessed in Nancowry Islands in Nicobar District to study the reasons for the observed upsurge in the number of cases, and to suggest public health measures to control the infection. Methods: The methods included a retrospective analysis of long term trend in the behaviour of malaria over the years from 2001 to 2008, analysis of the acute malaria situation, and rapid fever and malaria parasitemia survey along with environmental component. Mass radical therapy (MRT) and post-intervention parasitemia survey were carried out. The malaria situation in the aftermath of MRT was analysed. Results: During the post tsunami year (2005) there was a large increase in the incidence of malaria and this trend continued till 2008. The percentage of Plasmodium falciparum increased from 23 to 53 per cent from 2006 to 2007 that coincides with the labour influx from mainland. The study showed that Nancowry was highly endemic, with high transmission setting, and high risk area for malaria. Though, more number of migrant labourers suffered fever (75 vs 20%) and sought malaria treatment over past month but parasitemia survey showed higher point prevalence of malaria among native tribes (7.4 vs 6.5%). Post-MRT, there was a decline in the occurrence of malaria, though it did not last long. Interpretation & conclusions: The study findings suggest that the migrant workers hailing from non-endemic or moderately endemic settings became victims of malaria in epidemic proportion in high endemic and high transmission setting. To find out the reasons for deterioration of malaria situation at Nancowry in the aftermath of tsunami requires further research. PMID

  16. 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

  17. 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.

  18. Field survey of the Solomon Islands tsunami of 03 January 2010

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Kalligeris, N.

    2010-05-01

    We will present results of the post-tsunami survey being conducted at the time of submission of the tsunami generated on 03 January 2010 by a large earthquake in the vicinity of the Woodlark-Australia-Pacific triple junction in the Solomon Islands, with significant damage reported in Rendova.

  19. Tsunami hazard assessment in La Reunion and Mayotte Islands in the Indian Ocean : detailed modeling of tsunami impacts for the PREPARTOI project

    NASA Astrophysics Data System (ADS)

    Quentel, E.; Loevenbruck, A.; Sahal, A.; Lavigne, F.

    2011-12-01

    Significant tsunamis have often affected the southwest Indian Ocean. The scientific project PREPARTOI (Prévention et REcherche pour l'Atténuation du Risque Tsunami dans l'Océan Indien), partly founded by the MAIF foundation, aims at assessing the tsunami risk on both french islands of this region, La Réunion and Mayotte. Further purpose of this project is the detailed hazard and vulnerability study for specific places of these islands, selected according to their environmental and human issues and observed impacts of past tsunamis. Tsunami hazard in this region, recently highlighted by major events in the southwest Indian Ocean, has never been thoroughly evaluated. Our study, within the PREPARTOI project, contributes to fill in this lack. It aims at examining transoceanic tsunami hazard related to earthquakes by modeling the scenarios of major historical events. We consider earthquakes with magnitude greater than Mw 7.7 located on the Sumatra (1833, 2004, 2010), Java (2006) and Makran (1945) subduction zones. First, our simulations allow us to compare the tsunami impact at regional scale according to the seismic sources; we thus identify earthquakes locations which most affect the islands and describe the impact distribution along their coastline. In general, we note that, for the same magnitude, events coming from the southern part of Sumatra subduction zone induce a larger impact than the north events. The studied tsunamis initiated along the Java and Makran subduction zones have limited effects on both French islands. Then, detailed models for the selected sites are performed based on high resolution bathymetric and topographic data; they provide estimations of the water currents, the water heights and the potential inundations. When available, field measurements and maregraphic records allow testing our models. Arrival time, amplitude of the first wave and impact on the tide gauge time series are well reproduced. Models are consistent with the observations

  20. 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

  1. Tsunamis

    MedlinePlus

    A tsunami is a series of huge ocean waves created by an underwater disturbance. Causes include earthquakes, landslides, volcanic ... space that strike the surface of Earth. A tsunami can move hundreds of miles per hour in ...

  2. The Hawaiian Islands - Integrated Approach to Understanding the Tsunami Risk in the Pacific (Invited)

    NASA Astrophysics Data System (ADS)

    Chague-Goff, C.

    2013-12-01

    The Hawaiian Islands, because of their location in the middle of the Pacific Ocean, act as natural ';barometers' for tsunamis generated along the Pacific Ring of Fire, which is the most seismically active area in the world. A multi-proxy study in the remote Pololu valley on the Big Island provided the first evidence for two trans-Pacific events, namely the 1946 and 1957 Aleutian tsunamis. These were identified using radiometric, stratigraphic, microfossil, pollen and geochemical proxies and were corroborated by historical accounts. The islands have been impacted repeatedly by tsunamis in historical times (inc. the recent 2010 Maule and 2011 Tohoku-oki events), and there is strong archaeological evidence for large events affecting humans in prehistory. However, no geological research has yet been carried out, except for some associated with a palaeoecological study on Kauai. Historical evidence shows that tsunamis emanating from the Pacific Ring of Fire have run up to different elevations on different islands within the island chain depending upon their source. Here there is a possible key to understanding some of the key questions about the magnitude and frequency of tsunamis from various parts of the Pacific. Tsunamis from Japan are large on the SW side of the Big Island, those from Alaska seem to have been large in the NE of the island and so on throughout the island chain. A careful site selection from throughout the islands offers a unique opportunity to chart the palaeotsunami record of the Hawaiian Islands while at the same time matching and enhancing the palaeoseismic record of sources in the Pacific Ring of Fire. How big and how often events have occurred in circum-Pacific locations, and how badly they affected other Pacific nations may therefore be addressed by looking in the middle of the Pacific Ocean.

  3. 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

  4. 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

  5. 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

  6. 2007 Solomon Islands Tsunami Left Little Sand Onshore, Buried Backshore Reefs

    NASA Astrophysics Data System (ADS)

    Moore, A. L.; Jackson, K. L.; Kruger, J.; McAdoo, B. G.; Rafiau, W. B.; Tiano, B.; Woodward, S. M.

    2007-12-01

    In many places struck by the 2007 Solomon Islands tsunami, little onshore record of the tsunami's passage remains yet considerable sediment was transported offshore. This sediment represents an ecological hazard in tropical regions because of its potential for burying coral reefs. At Nusa Agana, a 50 m-wide, 2 m-high barrier island ~36 km N of the epicenter, flow depths recorded by debris wrapped around tree trunks did not exceed 50 cm--the sedimentary record on land was similarly small at ~2 cm thick. Nevertheless, the "outer" coastline of the island was stripped of sediment and the "inner" coastline filled with enough sediment to bury coral reefs to an extent that only soft corals at the top of the reef survive. The source of the sediment appears to be a mixture of sand from both the outer and inner beach, suggesting that scour occurred at both these locations. Perhaps because of the island's low relief, Nusa Agana acted less as a barrier to flow and more as a topographic high; sediment cover thinned over the high and selectively infilled the topographic low of the lagoon. At Tapurai, ~55 km ENE of the epicenter, the tsunami left a layer of coral rubble 20-30 cm thick and moved basalt boulders up to 1 m in diameter more than 100 m inland. The tsunami here reached flow depths of more than 8 m and swept N-SW across fan-shaped Tapurai, piling coral rubble mixed from offshore reefs and the modern beach onto farm fields before striking a basalt cliff behind the town and deflecting SW, carrying basalt debris with it before exiting through the town's harbor. The sediment leaves a vivid account of the passage of the wave, progressing from a solely coral rubble deposit to a mixed basalt-coral deposit and thinning downflow as sediment supply waned. Where the tsunami washed completely over islands, the side facing the waves is typically stripped of sediment, whereas the lee side shows a well developed scarp, suggesting that at least some tsunami scarps are formed during

  7. 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.

  8. 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

  9. 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

  10. 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/

  11. Ancestral heritage saves tribes during 1 April 2007 Solomon Islands tsunami

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Kalligeris, Nikos

    2008-01-01

    The 1 April 2007 magnitude Ms 8.1 earthquake off the New Georgia Group in the Solomon Islands generated a tsunami that killed 52 with locally focused 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 -1.5 m. A reconnaissance team deployed within one week investigated 65 coastal settlements on 13 remote Islands. The ancestral heritage ``run to high ground after an earthquake'' passed on to younger generations by survivors of smaller historic tsunamis triggered an immediate spontaneous self evacuation containing the death toll.

  12. 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.

  13. 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.

  14. Tsunami Risk Management in Pacific Island Countries and Territories (PICTs): Some Issues, Challenges and Ways Forward

    NASA Astrophysics Data System (ADS)

    Dominey-Howes, Dale; Goff, James

    2013-09-01

    The Pacific is well known for producing tsunamis, and events such as the 2011 Tōhoku-oki, Japan disaster demonstrate the vulnerability of coastal communities. We review what is known about the current state of tsunami risk management for Pacific Island countries and territories (PICTs), identify the issues and challenges associated with affecting meaningful tsunami disaster risk reduction (DRR) efforts and outline strategies and possible ways forward. Small island states are scattered across the vast Pacific region and these states have to varying degrees been affected by not only large tsunamis originating in circum-Pacific subduction zones, but also more regionally devastating events. Having outlined and described what is meant by the risk management process, the various problems associated with our current understanding of this process are examined. The poorly understood hazard related to local, regional and distant sources is investigated and the dominant focus on seismic events at the expense of other tsunami source types is noted. We reflect on the challenges of undertaking numerical modelling from generation to inundation and specifically detail the problems as they relate to PICTs. This is followed by an exploration of the challenges associated with mapping exposure and estimating vulnerability in low-lying coastal areas. The latter part of the paper is devoted to exploring what mitigation of the tsunami risk can look like and draw upon good practice cases as exemplars of the actions that can be taken from the local to regional level. Importantly, given the diversity of PICTs, no one approach will suit all places. The paper closes by making a series of recommendations to assist PICTs and the wider tsunami research community in thinking through improvements to their tsunami risk management processes and the research that can underpin these efforts.

  15. 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 ...

  16. The November 15, 2006 Kuril Islands-Generated Tsunami in Crescent City, California

    NASA Astrophysics Data System (ADS)

    Dengler, L.; Uslu, B.; Barberopoulou, A.; Yim, S. C.; Kelly, A.

    2009-02-01

    On November 15, 2006, Crescent City in Del Norte County, California was hit by a tsunami generated by a M w 8.3 earthquake in the central Kuril Islands. Strong currents that persisted over an eight-hour period damaged floating docks and several boats and caused an estimated 9.2 million in losses. Initial tsunami alert bulletins issued by the West Coast Alaska Tsunami Warning Center (WCATWC) in Palmer, Alaska were cancelled about three and a half hours after the earthquake, nearly five hours before the first surges reached Crescent City. The largest amplitude wave, 1.76-meter peak to trough, was the sixth cycle and arrived over two hours after the first wave. Strong currents estimated at over 10 knots, damaged or destroyed three docks and caused cracks in most of the remaining docks. As a result of the November 15 event, WCATWC changed the definition of Advisory from a region-wide alert bulletin meaning that a potential tsunami is 6 hours or further away to a localized alert that tsunami water heights may approach warning- level thresholds in specific, vulnerable locations like Crescent City. On January 13, 2007 a similar Kuril event occurred and hourly conferences between the warning center and regional weather forecasts were held with a considerable improvement in the flow of information to local coastal jurisdictions. The event highlighted the vulnerability of harbors from a relatively modest tsunami and underscored the need to improve public education regarding the duration of the tsunami hazards, improve dialog between tsunami warning centers and local jurisdictions, and better understand the currents produced by tsunamis in harbors.

  17. Earthquakes and tsunamis in Puerto Rico and the U.S. Virgin Islands

    USGS Publications Warehouse

    Nealon, J.W.; Dillon, William P.

    2001-01-01

    Many earthquakes and tsunamis have occurred in the northeastern Caribbean, where the movements of the Earth's surface plates are rapid and complicated. Future such events pose serious hazards to the 3.7 million people who live in Puerto Rico and the U.S. Virgin Islands.

  18. 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.

    2015-06-01

    On 6 February 2013 an Mw = 8.0 subduction earthquake occurred close to Santa Cruz Islands at the transition between the Solomon and the New Hebrides Trench. The ensuing tsunami caused significant inundation on the closest Nendo Island. The seismic source was studied with teleseismic broadband P-wave inversion optimized with tsunami forward modelling at DART buoys (Lay et al., 2013) and with inversion of teleseismic body and surface waves (Hayes et al., 2014a). The two studies also use different hypocentres and different planar fault models and found quite different slip models. In particular, Hayes et al. (2014a) argued for an aseismic slip patch SE from the hypocentre. We here develop a 3-D model of the fault surface from seismicity analysis and retrieve the tsunami source by inverting DART and tide-gauge data. Our tsunami source model features a main slip patch (peak value of ~ 11 m) SE of the hypocentre and reaching the trench. The rake direction is consistent with the progressively more oblique plate convergence towards the Solomon trench. The tsunami source partially overlaps the hypothesized aseismic slip area, which then might have slipped coseismically.

  19. 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.

    2015-03-01

    On 6 February 2013 an Mw 8.0 subduction earthquake occurred close to Santa Cruz Islands at the transition between the Solomon and the New Hebrides Trench. The ensuing tsunami caused significant inundation on the closest Nendo Island. The seismic source was studied with teleseismic broadband P waves inversion optimized with tsunami forward modeling at DART buoys (Lay et al., 2013), and with inversion of teleseismic body and surface waves (Hayes et al., 2014). The two studies also use different hypocenters and different planar fault models, and found quite different slip models. In particular, Hayes et al. (2014) argued for an aseismic slip patch SE from the hypocenter. We here develop a 3-D model of the fault surface from seismicity analysis and retrieve the tsunami source by inverting DART and tide-gauge data. Our tsunami source model features a main slip patch (peak value of ~11 m) SE of the hypocentre, and reaching to the trench. The rake direction is consistent with the progressively more oblique plate convergence towards the Solomon trench. The tsunami source partially overlaps the hypothesized aseismic slip area, which then might have slipped coseismically.

  20. The energetic 2010 MW 7.1 Solomon Islands tsunami earthquake

    NASA Astrophysics Data System (ADS)

    Newman, Andrew V.; Feng, Lujia; Fritz, Hermann M.; Lifton, Zachery M.; Kalligeris, Nikos; Wei, Yong

    2011-08-01

    On 2010 January 3 a moment magnitude MW 7.1 earthquake struck the Solomon Islands very near the San Cristobal trench, causing extensive landslides and surprisingly large tsunami waves. Because of the unique proximity of islands to the trench (<20 km) and earthquake, a post-seismic survey successfully identified unexpected widespread coseismic subsidence towards the trench (up to 80 cm), with no discernable post-seismic deformation. Approximately 1000 km from the earthquake ocean-bottom pressure sensors measured 1-2 cm open-ocean tsunami waves. Though spatially limited, the local tsunami wave heights up to 7 m were comparable to the much larger adjacent 2007 MW 8.1 earthquake. The seismically determined focal mechanism, broad-scale subsidence, tsunami amplitude and open ocean wave heights are all explained by an extremely shallow low-angle thrust adjacent to the impinging subduction of the two seamounts near the trench. This event belongs to a potentially new class of shallow 'tsunami earthquakes' that is not identified as deficient in radiated seismic energy.

  1. Impact of 2004 Tsunami in the Islands of Indian Ocean: Lessons Learned

    PubMed Central

    Ramalanjaona, Georges

    2011-01-01

    Tsunami of 2004, caused by a 9.0 magnitude earthquake, is the most devastating tsunami in modern times, affecting 18 countries in Southeast Asia and Southern Africa, killing more than 250,000 people in a single day, and leaving more than 1.7 million homeless. However, less reported, albeit real, is its impact in the islands of the Indian Ocean more than 1,000 miles away from its epicenter. This is the first peer-reviewed paper on the 2004 tsunami events specifically in the eleven nations bordering the Indian Ocean, as they constitute a region at risk, due to the presence of tectonic interactive plate, absence of a tsunami warning system in the Indian Ocean, and lack established communication network providing timely information to that region. Our paper has a dual objective: the first objective is to report the 2004 tsunami event in relation to the 11 nations bordering the Indian Ocean. The second one is to elaborate on lessons learned from it from national, regional, and international disaster management programs to prevent such devastating consequences of tsunami from occurring again in the future. PMID:22046551

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  8. 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.

  9. 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

  10. 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

  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. 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.

  13. 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

  14. User-driven science: earthquake and tsunami scenarios for the Mentawai Islands, western Sumatra

    NASA Astrophysics Data System (ADS)

    McCaughey, J.; Lubis, A. M.; Qiang, Q.; Huang, Z.; Hill, E. M.; Natawidjaja, D.; Sieh, K. E.

    2011-12-01

    Following recovery from a large tsunami on 25-Oct-2010 that killed over 500 people, the government of the Mentawai Regency turned its attention to developing a regional disaster-risk-reduction plan. Geodetic and coral studies show that an earthquake as large as M 8.8 is likely in the coming decades on the Mentawai patch of the Sunda megathrust, yet there had not been any tsunami-inundation maps produced for the Mentawai Islands based on this scenario. By request from the Mentawai government, we will develop such tsunami-inundation maps for populated areas. Uncertainties in the source models include whether the accumulated strain on the Sunda megathrust is released in one great earthquake or in a series of large earthquakes, limited scientific understanding of the seismic potential of the Mentawai backthrust that lies inboard (east) of the islands, and whether these sources would rupture to the surface in a particular earthquake. Low-resolution bathymetry adds uncertainty to our modeled tsunami flow depths and runups. Because the Mentawai government is currently planning for disaster risk reduction, we chose to produce the inundation map now. However, we may have a communication challenge if, a few years in the future, further research leads to significant revisions of the inundation map. We will communicate the results and uncertainty to the Mentawai government and partner local NGOs through an in-person workshop. Monitoring and evaluation will inform further communication efforts. However, the remote location of the Mentawai Islands and limited internet and phone service significantly limits our ability to communicate with end-users at the community level. Since our maps are likely to be parceled out and distributed to villages in hard copy, we need to include key information for each location, including uncertainty, on a single sheet. With local partners, we will investigate the best way to frame this information in the local context.

  15. 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.

  16. 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.

  17. 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.

  18. Effects of the March 2011 Japanese Tsunami in Bays and Estuaries of SE Australia

    NASA Astrophysics Data System (ADS)

    Hinwood, Jon B.; Mclean, Errol J.

    2013-06-01

    On 11 March 2011 a subsea earthquake off the north-eastern coast of Honshu Island, Japan generated a huge tsunami which was felt throughout the Pacific. At the opposite end of the Pacific Ocean, on the south-east coast of Australia, multiple reflections, scatterings and alternate pathways lead to a prolonged and complicated response. This response was largely unaltered in crossing the continental shelf but was then transformed by bay resonances and admittances. These effects are described using data from tide recorders sparsely spread over 1,000 km of the coast. Some new adaptations and applications of time-series analysis are applied to separate tsunami waves that have followed different pathways but contain the same spectral components. The possible types of harbour response are classified and illustrated. Despite its small height in this region, the tsunami put several swimmers at serious risk and generated strong harbour oscillations, which should be considered when generating future warnings.

  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. 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

  1. Effects of rupture complexity on local tsunami inundation: Implications for probabilistic tsunami hazard assessment by example

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    We investigated the influence of earthquake source complexity on the extent of inundation caused by the resulting tsunami. We simulated 100 scenarios with collocated sources of variable slip on the Hikurangi subduction interface in the vicinity of Hawke's Bay and Poverty Bay in New Zealand and investigated the tsunami effects on the cities of Napier and Gisborne. Rupture complexity was found to have a first-order effect on flow depth and inundation extent for local tsunami sources. 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. Assuming uniform slip on the rupture interface in tsunami models can 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 that could potentially be inundated by equivalent nonuniform slip events of Mw 8.4. Deaggregation, 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 two predictors for inundation severity based on the offshore tsunami wavefield using the linear wave equations in an attempt to keep costly simulations of full inundation to a minimum.

  2. 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.

  3. 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.                   

  4. 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

  5. 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

  6. The February 6, 2013 Mw 8.0 Santa Cruz Islands earthquake and tsunami

    NASA Astrophysics Data System (ADS)

    Lay, Thorne; Ye, Lingling; Kanamori, Hiroo; Yamazaki, Yoshiki; Cheung, Kwok Fai; Ammon, Charles J.

    2013-11-01

    The Santa Cruz Islands region has high seismicity near a 90° bend in the boundary between the Pacific and Australian plates. Southward, along the Vanuatu island arc, the Australian plate under-thrusts the Pacific plate in a well-defined subduction zone. Westward, a transpressional, predominantly transform boundary extends to the southern Solomon Islands subduction zone. The Santa Cruz Islands region has upper plate strike-slip and normal faulting, plate boundary under-thrusting, outer rise extensional faulting, and intraplate compressional faulting. On February 6, 2013 the largest under-thrusting earthquake (Mw 8.0) that has been instrumentally recorded in the region ruptured the megathrust. The epicenter (10.738°S, 165.138°E) is about 1° north of epicenters of prior large shallow under-thrusting events in Vanuatu in 1934 (M ~ 7.8) and 1966 (MS 7.9), and there is overlap of all three events' aftershock zones, but not their large-slip regions. At least 10 lives were lost, with 6 more missing, due to tsunami ~ 1.5 m high striking the town of Lata and several villages on the main Santa Cruz Island of Nendö (Ndeni) and a nearby small island Nibanga. Inundation of 500 m flooded the Lata airport. The tsunami was well-recorded by DART buoys spanning an unusually wide three-quadrant azimuthal aperture. Iterative modeling of teleseismic broadband P waves and the deep-water tsunami recordings resolves the slip distribution. There are two large-slip patches with a southeastward rupture expansion at about 1.5 km/s, with the second patch appearing to have ruptured with large slip at the trench. The event has relatively low short-period seismic wave energy release, but a typical overall moment-scaled total energy. The shallow rupture depth may be associated with the low level of short-period energy, and a near-total stress drop may account for a lack of underthrusting aftershocks among a highly productive aftershock sequence that included three events with Mw ≥ 7.0.

  7. Stratigraphic and Microfossil Evidence for Late Holocene Tsunamis at Swantown Marsh, Whidbey Island, Washington

    NASA Astrophysics Data System (ADS)

    Williams, Harry; Hutchinson, Ian

    2000-09-01

    Four muddy sand sheets occur within a tidal marsh peat at Swantown on the west coast of Whidbey Island, Washington. The two largest sand sheets pinch out about 100 m inland and became thinner and finer-grained landward. All four sand sheets contain marine microfossils and have internal stratification. They record repeated inundation of the marsh over a short time period by distinct pulses of sediment-laden ocean water, consistent with deposition by a tsunami wave train. The layers have been radiocarbon-dated to 1160-1350, 1400-1700, 1810-2060, and 1830-2120 cal yr B.P. The overlap in age between the two youngest layers and inferred great earthquake events at the Cascadia plate boundary, some 250 km to the west, suggests they were emplaced by tsunamis from this source area. The two older layers do not correlate with plate-boundary events. They may be products of tsunamis caused by earthquakes on local faults in the Strait of Juan de Fuca or by submarine landslides in this area.

  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. Establishing an early warning alert and response network following the Solomon Islands tsunami in 2013

    PubMed Central

    Bilve, Augustine; Nogareda, Francisco; Joshua, Cynthia; Ross, Lester; Betcha, Christopher; Durski, Kara; Fleischl, Juliet

    2014-01-01

    Abstract Problem On 6 February 2013, an 8.0 magnitude earthquake generated a tsunami that struck the Santa Cruz Islands, Solomon Islands, killing 10 people and displacing over 4700. Approach A post-disaster assessment of the risk of epidemic disease transmission recommended the implementation of an early warning alert and response network (EWARN) to rapidly detect, assess and respond to potential outbreaks in the aftermath of the tsunami. Local setting Almost 40% of the Santa Cruz Islands’ population were displaced by the disaster, and living in cramped temporary camps with poor or absent sanitation facilities and insufficient access to clean water. There was no early warning disease surveillance system. Relevant changes By 25 February, an EWARN was operational in five health facilities that served 90% of the displaced population. Eight priority diseases or syndromes were reported weekly; unexpected health events were reported immediately. Between 25 February and 19 May, 1177 target diseases or syndrome cases were reported. Seven alerts were investigated. No sustained transmission or epidemics were identified. Reporting compliance was 85%. The EWARN was then transitioned to the routine four-syndrome early warning disease surveillance system. Lesson learnt It was necessary to conduct a detailed assessment to evaluate the risk and potential impact of serious infectious disease outbreaks, to assess whether and how enhanced early warning disease surveillance should be implemented. Local capacities and available resources should be considered in planning EWARN implementation. An EWARN can be an opportunity to establish or strengthen early warning disease surveillance capabilities. PMID:25378746

  11. 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.

  12. 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

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

    NASA Astrophysics Data System (ADS)

    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. 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

  15. Local tsunami early warning: the case of Rhodes island, Greece, and the NEARTOWARN (EU-DG ECHO) prevention project

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Gerassimos; Argyris, Ilias; Fokaefs, Anna

    2013-04-01

    Local, that is near-field, tsunamis occur in the global ocean including the Mediterranean Sea and its connected seas. For such tsunamis the first wave has very short travel time of arrival (less than 30 min.) to the closest coastal zone thus making the early warning a very difficult task. An efficient, end-to-end early tsunami warning system in local conditions should fulfill the condition that the time needed for the earthquake detection, plus the time needed for the warning message transmission to the authorities and afterwards to the general public and/or other task groups, plus the time needed for response and real evacuation is less than the travel time of the first wave. In the physiographic conditions of the Mediterranean Sea it is extremely hard to satisfy such a condition unless the total time needed to response in early warning is drastically minimized. The project Near-Field Tsunami Warning and Emergency Planning (NEARTOWARN, which is supported by the EU DG-ECHO prevention programme, aims, among others, to establish a system in Rhodes island, Greece, with the purpose to meet needs for local early tsunami warning. To minimize the time for emergency in less than 30 sec, seismic alert devices (SED's) make the core component of the system. SED's are activated and send alerting signals as soon as a P-phase of seismic wave is detected in the near-field but for a predetermined threshold of ground motion. Then, emergency starts while SED's activate remotely other devices, such as computers with data bases of pre-calculated tsunami simulations, surveillance cameras etc. The system is completed with tide-gauges, simulated tsunami scenarios and emergency planning supported by a Geographical Management System. Rhodes island in Dodecanese, South Aegean Sea, Greece, has been selected as a test-area for the development of the prototype system given that it was hit by large tsunamigenic earthquakes several times in the past.

  16. Tsunami risk assessment in the Marquesas Islands (French Polynesia) through numerical modeling of generic far-field events

    NASA Astrophysics Data System (ADS)

    Hébert, H.; Schindelé, F.; Heinrich, P.

    Earthquakes occurring at the Pacific Rim can trigger tsunamis that propagate across the ocean and can produce significant damages far away from the source. In French Polynesia, the Marquesas Islands are the most exposed to the far-field tsunami hazards, since they are not protected by any outer coral reef and since submarine slopes are less steep than in other islands. Between 1994 and 1996, four tsunamis have reached the bays of the archipelago, among them, the tsunami initiated by the Chilean Mw 8.1 earthquake, produced up to 3 m high waves in Tahauku Bay. Numerical modeling of these recent events has already allowed us to validate our method of resolution of hydrodynamics laws through a finite-difference scheme that simulates the propagation of the tsunamis across the ocean and computes the inundation heights (run-up) in remote bays. We present in this paper the simulations carried out to study potentially threatening areas located at the Pacific Rim, on the seismogenic Aleutian and Tonga subduction zones. We use a constant seismic moment source (that of the Mw 8.1 Chile 1995 earthquake, M0 = 1.2 1021 N.m) located at several potential epicenters, with the fault strike adapted from the regional seismotectonics pattern. Our results show that the sources chosen in the Aleutian trench do not produce large inundations in the Marquesas bays, except for the easternmost source (longitude 194° E). Sources located in the Tonga trench do not produce high amplifications either, except for the northernmost one (latitude 16° S). We also discuss the behaviour of the tsunami waves within the archipelago, and evidence contrasting responses depending on the arrival azimuths. These results show that, for a given initial seismic energy, the tsunami amplification in remote bays is highly dependent on the source location and fault strike.

  17. 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

  18. 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

  19. Tsunami: psychosocial aspects of Andaman and Nicobar islands. Assessments and intervention in the early phase.

    PubMed

    Math, Suresh Bada; Girimaji, Satish Chandra; Benegal, Vivek; Uday Kumar, G S; Hamza, Ameer; Nagaraja, D

    2006-06-01

    The aim of this paper is to describe the activities and observations of the team from National Institute of Mental Health and Neuro Sciences (NIMHANS) Bangalore, India in the Andaman and Nicobar Islands during the early phase of the Tsunami disaster in January and February 2005. The activities comprised mental health consultation at camps, community sensitization, mental health services to the students and children, teachers orientation sessions and training of non-governmental organization [NGO] functionaries. Initial assessment reveals 5-8% of the population were suffering from significant mental health problems following the early phase of the disaster. This may increase in the aftermath of the early relief phase. Psychiatric morbidity is expected be around 25-30% in the disillusionment phase. High resilience was seen in the joint family system of tribal Nicobarese during early phase of disaster. In developing countries like India, limited availability of mental health professionals and poor knowledge about disaster mental health among the medical and para-medical staff, may lead to poor psychosocial rehabilitation of the survivors. To respond to a high magnitude natural disaster like a tsunami, the disaster mental health team must be able to understand the local culture, traditions, language, belief systems and local livelihood patterns. They also need to integrate with the network of various governmental and non-governmental organizations to cater to the needs of the survivors. Hence the presence of a disaster mental health team is definitely required during the early phase of the disaster in developing countries. PMID:16753660

  20. 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

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

    USGS Publications Warehouse

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

    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.

  2. 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. PMID:17509746

  3. New Tsunami Forecast Tools for the French Polynesia Tsunami Warning System Part II: Numerical Modelling and Tsunami Height Estimation

    NASA Astrophysics Data System (ADS)

    Jamelot, Anthony; Reymond, Dominique

    2015-03-01

    Tsunami warning is classically based on two fundamental tools: the first one concerns the source parameters estimations, and the second one is the tsunami amplitude forecast. We presented in the first companion paper how the seismic source parameters are evaluated, and this second article describes the operational aspect and accuracy of the estimation of tsunami height using tsunami numerical modelling on a dedicated supercomputer (2.5 T-flops). The French Polynesian tsunami warning centre developed two new tsunami forecast tools for a tsunami warning context, based on our tsunami propagation numerical model named Taitoko. The first tool, named MERIT, that is very rapid, provides a preliminary forecast distribution of the tsunami amplitude for 30 sites located in French Polynesia in less than 5 min. In this case, the coastal tsunami height distribution is calculated from the numerical simulation of the tsunami amplitude in deep ocean using an empirical transfer function inspired by the Green Law. This method, which does not take into account resonance effects of bays and harbour, is suitable for rapid and first estimation of the tsunami danger. The second method, named COASTER, which uses 21 nested grids of increasing resolutions, gives more information about the coastal tsunami effects about the flow velocities, the arrival time of the maximal amplitude, and the maximal run-up height for five representative sites in 45 min. The historical tsunamis recorded over the last 22 years in French Polynesia have been simulated with these new tools to evaluate the accuracy of these methods. The results of the 23 historical tsunami simulations have been compared to the tide-gauge records of three sites in French Polynesia. The results, which are quite encouraging, shows standard errors of generally less than a 2 factor : the maximal standard error is 0.38 m for the Tahauku Bay of Hiva-Oa (Marquesas islands).

  4. 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.

  5. 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

  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. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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…

  13. Tsunami hazard assessment of Guadeloupe Island (F.W.I.) related to a megathrust rupture on the Lesser Antilles subduction interface

    NASA Astrophysics Data System (ADS)

    Roger, J.; Dudon, B.; Zahibo, N.

    2013-05-01

    The French Caribbean Archipelago of Guadeloupe is located over the Lesser Antilles active subduction zone, where a handful of earthquakes have reached magnitudes of Mw = 7.0 (moment magnitude) and more. According to available catalogs, these earthquakes have been able to trigger devastating tsunamis, either directly by the shake or indirectly by induced landslides. The Guadeloupe Archipelago is known to have suffered from several violent earthquakes, including the 1843 Mw ~ 8.5 megathrust event. In this study, we discuss the potential impact of a tsunami generation scenario of a Mw = 8.5 rupture at the subduction interface using numerical modeling and high resolution bathymetric data within the framework of tsunami hazard assessment for Guadeloupe. Despite the fact that the mystery remains unresolved concerning the lack of historical tsunami data for the 1843 event, modeling results show that the tsunami impact is not uniformly distributed in the whole archipelago and could show important maximum wave heights. This is easily explained by the bathymetry and the presence of several islands around the main island leading to resonance phenomena, and because of the existence of a fringing coral reef partially surrounding Guadeloupe Island and its satellites. We then discuss the role of source parameters, the arrival times and the protective role of fringing coral reefs surrounding the islands, using tsunami modeling applied on two Guadeloupian touristic coastal places: Sainte-Anne and Saint-François.

  14. 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.

  15. 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

  16. 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.

  17. 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

  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. Cascadia Tsunami Deposit Database

    USGS Publications Warehouse

    Peters, Robert; Jaffe, Bruce; Gelfenbaum, Guy; Peterson, Curt

    2003-01-01

    The Cascadia Tsunami Deposit Database contains data on the location and sedimentological properties of tsunami deposits found along the Cascadia margin. Data have been compiled from 52 studies, documenting 59 sites from northern California to Vancouver Island, British Columbia that contain known or potential tsunami deposits. Bibliographical references are provided for all sites included in the database. Cascadia tsunami deposits are usually seen as anomalous sand layers in coastal marsh or lake sediments. The studies cited in the database use numerous criteria based on sedimentary characteristics to distinguish tsunami deposits from sand layers deposited by other processes, such as river flooding and storm surges. Several studies cited in the database contain evidence for more than one tsunami at a site. Data categories include age, thickness, layering, grainsize, and other sedimentological characteristics of Cascadia tsunami deposits. The database documents the variability observed in tsunami deposits found along the Cascadia margin.

  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. 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. PMID:23224070

  2. Modeling of a 1960'th Chilean tsunami in Pacific Ocean within nonlinear-dispersive theory of long waves

    NASA Astrophysics Data System (ADS)

    Chernov, A.; Korytko, A.; Kostenko, I.; Pelinovsky, E.; Yalciner, A.; Zaytsev, A.

    2009-04-01

    1960 Chilean centered Pacific Ocean tsunami and 2004 North West Sumatra centered Indian Ocean Tsunami are two important tsunamis of long distance propagation and impacts of tsunamis. Recent international studies on the propagation and dispersion effects of Indian Ocean tsunami showed that dispersion is one of the important parameters of numerical solutions of tsunami propagation. May 23, 1960 earthquake with the approximate magnitude 9.0 caused approximately 750km rupture and generated tsunami at offshore Chilean Coast. Tsunami has reached 15-20m height at Chilean coast. The effects of this tsunami were observed not only near Chilean Coast but also in Japan after 22 hours propagation. Chilean tsunami was also felt in Kuril Islands and tsunami height reached to 4.7m near Severo-Kurilsk (Paramushir Island). Houses near the coast, warehouses and mooring facilities have been flooded. In Malokurilsk (Shikotan Island), the height of tsunami reached 4m, flooded the moorings facilities and some buildings, and damaged the bridge on a land. Many vessels became stranded because of broken anchors. Tsunami was also observed on all islands of the Kuril Ridge. The maximal height of rising of water was 4m at Shikotan Islands and 2.2m at on Kunashir Island, 2.5m at Iturup Island, and 1.3-1.5m at Matua Island. Tsunami entered the Sea of Okhotsk. In Magadan the height of rising of water was 2.2 m. the weak tsunami also was observed near Sakhalin Island. The dispersion effect of 1960 Chilean tsunami and its long distance effects on Kuril Ridge have not been studied yet. In this study we developed the numerical model solving the long distance propagation of 1960 Chilean tsunami in Pacific Ocean and the assessment of its far field effects at Kuril Ridge. According to the modeling efforts, we made comparisons between the results of the numerical solutions using dispersive and non-dispersive long wave equations. The dispersion effects of long distance propagation of 1960 Chilean tsunami

  3. 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.

  4. 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.

  5. 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

  6. 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

  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. 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

  9. 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.

  10. 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

  11. 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

  12. Ironic Effects of the Destructive Tsunami on Public Risk Judgment

    NASA Astrophysics Data System (ADS)

    Oki, S.; Nakayachi, K.

    2011-12-01

    The 2011 Tohoku earthquake caused more than 20,000 casualties, with most of the dead and missing in an enormous tsunami. Survivors had simply evacuated to higher ground within approximately 30 minutes of its arrival. This reflects the importance of public perception of tsunami risks represented by its heights. Our question is how the devastating tsunami affected people in the western Japan where a great earthquake is anticipated in near future. Existing risk analysis researches show that the experience of natural disasters increases risk perception, even with indirect experiences such as seeing photographs of disaster scenes or thinking about a major natural calamity. No doubt, we can assume that the devastating tsunami would have led people to have a greater sense of associated risks. Our result, however, shows that the destructive tsunami of Tohoku earthquake lowered the risk assessment of tsunami heights. One possible explanation to this paradoxical result is the anchoring heuristic. It defines that laypersons are highly inclined to judge based on the numbers first presented to them. Media's repeating report of record-breaking tsunamis of 30 m or more anchored people to elevate the height to evacuate. The results of our survey pose a significant problem for disaster prevention. The survey area is at high risk of giant earthquake, and according to our results, more than 50% of the people surveyed no longer sensed the danger of a 1-m-high tsunami, whereas about 70% had perceived its peril before the Tohoku earthquake. This is also of great importance in Indonesia or Chile where huge earthquakes had occurred recently. We scientists need to face up to the fact that improvement of quick calculation of tsunami heights is not sufficient at all to mitigate the tsunami disasters, but reorient how we should inform laypersons to evacuate at the emergency situation.

  13. An Island Effect in Japanese.

    ERIC Educational Resources Information Center

    Richards, Norvin

    2000-01-01

    Develops an argument for a pied-piping approach to the apparent absence of island effects in Japanese, along the lines of Nishigauchi (1986, 1990). Investigates the nature of pied-piping, developing a theory that accounts for the fact that wh-islands cannot be pied-piped. (Author/VWL)

  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. Tsunami in the China Seas and its warning service

    SciTech Connect

    Ye Lin; Wang Xinian; Bao Chenglan

    1993-12-31

    This paper briefly describes the tsunamis that took place in the China Seas, discusses the possibility of influence of crossing oceanic tsunami on the China Seas, and emphatically introduces the tsunami along Hainan Island coasts in January 1992. It is the seldom tsunami recorded completely by instruments in China. Last, the operation of tsunami warning service in China is presented.

  16. 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

    2016-06-01

    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.

  17. 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

  18. Effect of depth-dependent shear modulus on tsunami generation along subduction zones

    USGS Publications Warehouse

    Geist, E.L.; Bilek, S.L.

    2001-01-01

    Estimates of the initial size of tsunamis generated by subduction zone earthquakes are significantly affected by the choice of shear modulus at shallow depths. Analysis of over 360 circum-Pacific subduction zone earthquakes indicates that for a given seismic moment, source duration increases significantly with decreasing depth (Bilek and Lay, 1998; 1999). Under the assumption that stress drop is constant, the increase of source duration is explained by a 5-fold reduction of shear modulus from depths of 20 km to 5 km. This much lower value of shear modulus at shallow depths in comparison to standard earth models has the effect of increasing the amount of slip estimated from seismic moment determinations, thereby increasing tsunami amplitude. The effect of using depth dependent shear modulus values is tested by modeling the tsunami from the 1992 Nicaraguan tsunami earthquake using a previously determined moment distribution (lhmle??, 1996a). We find that the tide gauge record of this tsunami is well matched by synthetics created using the depth dependent shear modulus and moment distribution. Because excitation of seismic waves also depends on elastic heterogeneity, it is important, particularly for the inversion of short period waves, that a consistent seismic/tsunami shear modulus model be used for calculating slip distributions.

  19. 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.

  20. High-energy deposits newly recognized in Hawaii Island (South Point): a catastrophic tsunami generated by South Kona or Kalae flank collapse?

    NASA Astrophysics Data System (ADS)

    Marques, F. O.; Hildenbrand, A.; McMurtry, G. M.

    2012-12-01

    Most of the population and economic activity on Earth is concentrated in coastal areas. Tsunamis, in particular, represent a major threat, because they can travel great distances and impact the far surrounding shorelines within a few hours and cause considerable damage. Two main geological processes can generate destructive tsunamis: (1) high-magnitude earthquakes within the oceans, mostly along active margins, which can generate long-wavelength, low amplitude waves; and (2) giant mass-movements, such as catastrophic flank failure at oceanic volcanoes, which can instantaneously mobilize great amounts of material (several hundreds of km3) and generate high amplitude, medium-wavelength tsunamis. The Hawaiian volcanic chain has been affected by the largest landslides on Earth. Big Island, especially, has faced several catastrophic episodes of flank destabilization, the number, the amplitude and the age of which remain controversial. Knowing that there were flank collapses in South Kona and Kalae, we went to South Point to look for onland evidence of the collapse(s) and related tsunami(s), and found a deposit composed of polygenetic clasts, from mm3 to several m3 in size, mostly angular to sub-rounded, with a sandy to silty matrix. The deposit is covered by pyroclasts (the Pahala ash?), which seem to have been locally remobilized to fill in the spaces in the underlying conglomeratic deposit. The absence of a continuous indurate cement precludes an inland origin for the sedimentary deposit. Moreover, the South Point deposit lies on a flat platform far from the main topographic relief of the Mauna Loa and Kilauea volcanoes. Emplacement of the ash layers covering the deposits requires a highly explosive eruption, which we attribute to pressure release driven by the collapse. Presently the deposit is lying at an altitude of ca. 10 m, but in the past it was higher, since the island has experienced significant ongoing subsidence. From previous estimates of the age of the

  1. The effect of traumatic bereavement on tsunami-exposed survivors.

    PubMed

    Johannesson, Kerstin Bergh; Lundin, Tom; Hultman, Christina M; Lindam, Anna; Dyster-Aas, Johan; Arnberg, Filip; Michel, Per-Olof

    2009-12-01

    Fourteen months after the 2004 tsunami, mental health outcome was assessed in 187 bereaved relatives, 308 bereaved friends, and in 3,020 nonbereaved Swedish survivors. Of the bereaved relatives, 41% reported posttraumatic stress reactions and 62% reported impaired general mental health. Having been caught or chased by the tsunami in combination with bereavement was associated with increased posttraumatic stress reactions. Complicated grief reactions among relatives were almost as frequent as posttraumatic stress reactions. The highest levels of psychological distress were found among those who had lost children. Traumatic bereavement, in combination with exposure to life danger, is probably a risk factor for mental health sequelae after a natural disaster. PMID:19937645

  2. 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. PMID:17447612

  3. 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.

  4. Tsunami: The Underrated Hazard

    NASA Astrophysics Data System (ADS)

    Synolakis, Costas; Fryer, Gerard J.

    Tsunami: the Underrated Hazard, by Edward Bryant, would appear to be a welcome addition to the scholarly tsunami literature. No book on tsunamis has the broad perspective of this work. The book looks attractive, with many high-quality photographs. It looks comprehensive, with discussions of tsunami hydrodynamics, tsunami effects on coastal landscapes, and causes of tsunamis (earthquakes, landslides, volcanic eruptions, meteorite impacts). It looks practical, with a section on risk and mitigation. It also looks entertaining, with an opening chapter on tsunami legends and a closing chapter presenting fanciful descriptions of imagined events. Appearances are deceiving, though. Any initial enthusiasm for the work evaporates on even casual reading. The book is so flawed by errors, omissions, confusion, and unsupported conjecture that we cannot recommend it to anyone.

  5. Dispersion and nonlinear effects in the 2011 Tohoku-Oki earthquake tsunami

    NASA Astrophysics Data System (ADS)

    Saito, Tatsuhiko; Inazu, Daisuke; Miyoshi, Takayuki; Hino, Ryota

    2014-08-01

    This study reveals the roles of the wave dispersion and nonlinear effects for the 2011 Tohoku-Oki earthquake tsunami. We conducted tsunami simulations based on the nonlinear dispersive equations with a high-resolution source model. The simulations successfully reproduced the waveforms recorded in the offshore, deep sea, and focal areas. The calculated inundation area coincided well with the actual inundation for the Sendai Plain, which was the widest inundation area during this event. By conducting sets of simulations with different tsunami equations, we obtained the followings insights into the wave dispersion, nonlinear effects, and energy dissipation for this event. Although the wave dispersion was neglected in most studies, the maximum amplitude was significantly overestimated in the deep sea if the dispersion was not included. The waveform observed at the station with the largest tsunami height (˜2 m) among the deep-ocean stations also verified the necessity of the dispersion. It is well known that the nonlinear effects play an important role for the propagation of a tsunami into bays and harbors. Additionally, nonlinear effects need to be considered to accurately model later waves, even for offshore stations. In particular, including nonlinear terms rather than the inundation was more important when precisely modeling the waves reflected from the coast.

  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. Investigation on tsunami effects in the central Adriatic Sea during the last century - a contribution

    NASA Astrophysics Data System (ADS)

    Maramai, A.; Graziani, L.; Tinti, S.

    2007-01-01

    In this work we present the result of a study aimed at examining the Italian earthquake sequences that occurred in the area of the central Adriatic sea with the purpose of understanding whether some of them were accompanied by tsunami effects. The motivation for this research was the update and enrichment of the Italian Tsunami Catalogue. The result was that evidence was found for two new cases of earthquake-induced tsunamis: these are the August 1916 Rimini and the October 1930 Ancona events. The bulk of the present research consisted in collecting all the available data on the earthquakes that affected the selected area in the past century and in identifying those potentially capable of generating tsunamis. During the study all the available material was gathered, which includes specific monographs and scientific papers, articles available in contemporary chronicles and in local and national newspapers. The final result of this research will improve our knowledge of the tsunamigenic activity of the central Adriatic sea and contribute to the assessment of the tsunami hazard and risk along these coasts, that especially in the peak season form one of the most densely populated areas of the Italian peninsula with flat and large beaches and water front resorts crowded of tourists.

  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. Field data and satellite imagery of tsunami effects in Banda Aceh.

    PubMed

    Borrero, Jose C

    2005-06-10

    After the 26 December 2004 earthquake and tsunami, field data on the extent of the inundation in Banda Aceh, Sumatra, were combined with satellite imagery to quantify the tsunami effects. Flow depths along the shores of Banda Aceh exceeded 9 meters, with inundation reaching 3 to 4 kilometers inland. To the southwest, at Lhoknga, flow depths were more than 15 meters at the shoreline and runup exceeded 25 meters. Erosion and subsidence moved the shoreline of Banda Aceh inland up to 1.5 kilometers, and 65 square kilometers of land between Banda Aceh and Lhoknga were flooded. PMID:15947180

  10. 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. PMID:26392622

  11. 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.

  12. Recognizing seiche and tsunami effects in lake sediments

    NASA Astrophysics Data System (ADS)

    Marco, Shmuel; Alsop, Ian G.; Katz, Oded; Dray, Yehoshua

    2014-05-01

    The lacustrine 70-15-ka Lisan Formation outcropping around the Dead Sea contains superb examples of slump folds formed in water depths of <100 m. New structural data from individual horizons demonstrate that several of these gravity-driven slumps are coaxially refolded and reworked by folds and thrusts verging both back up and then down the palaeoslope. The uppermost folds are often truncated. A progressive increase in reworking and shearing is developed up through the folded sediment, culminating in an upward-finning breccia layer that is capped by a thin, typically graded horizon of undeformed fine-grained clasts. We interpret this sequence as a seiche-related deformation. Based on the similarity of the structures in the Lisan Formation and on additional supporting observations we interpret zigzag-shaped sand injections in artificial lake deposits on the Eastern Mediterranean shore as evidence for a tsunami, possibly associated with the earthquake of 25 November 1759. If this interpretation is correct it supports the hypothesis that onshore Dead Sea Fault earthquakes can trigger tsunamis in the Mediterranean.

  13. Investigating the coastal paleo-seismic and paleo-tsunami records using vermetid benches in the Eastern Mediterranean: case of the Palm Islands reserve -Lebanon.

    NASA Astrophysics Data System (ADS)

    Elias, A.

    2014-12-01

    The vermetid benches or reefs are thick bio-constructions of marine shells of the Vermetidae group that thrive at sea-level and are used as proxy for crustal tectonic deformation, sea-level changes, paleoclimate reconstruction or paleo-Tsunami markers in different regions especially around the Mediterranean Sea. The Palm Islands Reserve located 5km offshore northern Lebanon in the Eastern Mediterranean, on the hanging wall of a submarine, active thrust fault - the Rankine-Abdeh fault - hold abundant vermetid bio-constructions that are still relatively well preserved. It is an exceptional site for testing and investigating hypothesis on the use of the vermetid benches. We surveyed the surface and shorelines of the Palm Island, the largest of the Islands. The fossil vermetid bio-constructions are present as uplifted benches on its northern side. Also, many of the large boulders mostly found on the south-western shore of the islands still hold vermetid bio-constructions originally from the intertidal position before the boulders were uplifted and thrown over the surface of the island away from the shoreline by powerful waves. Two continuous vertical sections of these bio-constructions, 7 and 13cm thick were sampled for radiocarbon dating. Of the 21 large boulders we surveyed 10 had their vermetid crusts sampled for 14C dating. Their measured radiocarbon ages are spread over many centuries and do not cluster around any single date that could correspond with that of a tsunami or storm event responsible for their transport. On another hand the radiocarbon ages from the uplifted benches show that the last co-seismic rupture of the underlying and offshore Rankine-Abdeh thrust took place after the 9th century AD and resulted in the tectonic uplift of the Palm Islands shoreline, by around 80cm. Interpretation of the morphology and ages of the vermetid bio-constructions found on the overthrown boulders suggest that another such co-seismic event happened towards the end of the

  14. Deep infrasound radiated by the Sumatra earthquake and tsunami

    NASA Astrophysics Data System (ADS)

    Garcés, M.; Caron, P.; Hetzer, C.; Le Pichon, A.; Bass, H.; Drob, D.; Bhattacharyya, J.

    Infrasound arrays in the Pacific and Indian oceans that are part of the International Monitoring System (IMS) of the Comprehensive Nuclear Test Ban Treaty (CTBT) recorded distinct signatures associated with the 26 December 2004 Sumatra earthquake (M/9, http://earthquake.usgs.gov/) and tsunami. Although the radiation of infrasound from large continental earthquakes is established [e.g., Le Pichon et al., 2003], the results presented in the present article indicate that islands undergoing significant surface displacements from submarine earthquakes can produce infrasound.Far more intriguing is the possibility that the initiation and propagation of a tsunami may produce low-frequency sound near the source as well as along coastlines and basins. Since distant sound effectively propagates at ˜300 m/s and tsunamis propagate at ˜200 m/s, precursory sound could potentially be used as a discriminant for tsunami genesis.

  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. Probabilistic Tsunami Hazard Analysis

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  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. 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

  20. The Effect of Horizontal Advection of Topography and Time Dependent Crustal Deformation on Tsunami Generation

    NASA Astrophysics Data System (ADS)

    Barak, S.; Beroza, G. C.

    2013-12-01

    Initial conditions used in tsunami modeling are commonly simplified due to lack of observations, poor understanding of the mechanics of tsunami generation, and limitations on computational power and processing time. First, since the time-varying deformation of the seafloor has a negligible effect far from the source, often, only the static, or the residual deformation is used to excite the tsunami model. However, when the earthquake occurs close to the coast, the dynamic displacement of the seafloor might have a significant effect on coastal wave height and arrival time. Second, it is common to use only the vertical component of the seafloor displacement, while neglecting the horizontal co-seismic displacements in the absence of landslides. While this assumption is valid for a flat or shallowly-dipping seafloor, it has been shown that in certain conditions, such as the combination of a shallow-dipping thrust fault with relatively steep topography, the contribution of the horizontal displacement is significant and might help explain discrepancies in wave height predictions. In this study we are using the abundant observations recorded during the 2011 Tohoku-Oki earthquake and tsunami to study the effects of time-varying deformation and the contribution of horizontal seafloor displacement on tsunami generation. We use SPECFEM3D, a spectral element numerical code, to solve the elasto-dynamic problem including wave propagation and the residual static deformation, to determine the time-dependent seafloor deformation. To simulate the earthquake we use a kinematic rupture model, in which the fault slip (magnitude and direction) is determined at each point in space and time for the assumed fault geometry. In order to test the contribution of topography we run the simulation with and without the surface topography and compare the results. In addition, we compare our results to real observations, where they are available, to validate of our model. Finally, our next step will

  1. Modeling of tsunamis and hurricanes as causes of the catastrophic overwash of Anegada, British Virgin Islands, between 1650 and 1800

    NASA Astrophysics Data System (ADS)

    Wei, Y.; ten Brink, U. S.; Atwater, B. F.

    2010-12-01

    The giant 2004 Aceh-Andaman earthquake and its Indian Ocean tsunami have spurred reassessment of earthquake and tsunami potential at subduction zones worldwide. Some of these zones resemble the source area of the 2004 earthquake in having a highly oblique convergence and little or no written record of great (M 8.0 or larger) thrust earthquakes. Some scientists have questioned whether subduction rate and subducting-plate age control the maximum earthquake size (Stein and Okal, 2007), even stating that all subduction zones long enough to make a giant (M 9) earthquake should be assumed capable of doing so (McCaffrey, 2008). In the present study, we seek to explain geological evidence for overwash, sometime between 1650 and 1800, at Anegada, northeast of Puerto Rico and 120 km south of the Puerto Rico Trench. Anegada offers three kinds of well-preserved evidence for a one-time overwash from the island’s north side during the decades between 1650 and 1800: dozens of elongate breaches cutting through sandy beach ridges of Anegada's north shore, which is protected from storm waves by a fringing reef; a sheet of sand and shell traced as much as 1.5 km southward inland from that shore; and fields of scattered boulders and cobbles moved southward and derived, in one case, from limestone outcrops 1 km south of the shore. Here we use tsunami modeling, tied to geological and written observations, to explore the earthquake and tsunami potential of the northern Antilles subduction zone. The plate convergence here is highly oblique, and there is no compelling written evidence, nor any instrumental evidence, for the occurrence of a great earthquake along the Puerto Rico Trench east of Hispaniola. We present tsunami simulations for four hypothetical sources, three along the Puerto Rico Trench and one in the Azores-Gibraltar convergence zone. We compare the model output with inundation inferred from the overwash evidence and with tsunamis, or their absence, recorded in writing in

  2. Anatomy of Historical Tsunamis: Lessons Learned for Tsunami Warning

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

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

  3. Validation of linearity assumptions for using tsunami waveforms in joint inversion of kinematic rupture models: Application to the 2010 Mentawai Mw 7.8 tsunami earthquake

    NASA Astrophysics Data System (ADS)

    Yue, Han; Lay, Thorne; Li, Linyan; Yamazaki, Yoshiki; Cheung, Kwok Fai; Rivera, Luis; Hill, Emma M.; Sieh, Kerry; Kongko, Widjo; Muhari, Abdul

    2015-03-01

    Tsunami observations have particular importance for resolving shallow offshore slip in finite-fault rupture model inversions for large subduction zone earthquakes. However, validations of amplitude linearity and choice of subfault discretization of tsunami Green's functions are essential when inverting tsunami waveforms. We explore such validations using four tsunami recordings of the 25 October 2010 Mentawai Mw 7.8 tsunami earthquake, jointly inverted with teleseismic body waves and 1 Hz GPS (high-rate GPS) observations. The tsunami observations include near-field and far-field deep water recordings, as well as coastal and island tide gauge recordings. A nonlinear, dispersive modeling code, NEOWAVE, is used to construct tsunami Green's functions from seafloor excitation for the linear inversions, along with performing full-scale calculations of the tsunami for the inverted models. We explore linearity and finiteness effects with respect to slip magnitude, variable rake determination, and subfault dimensions. The linearity assumption is generally robust for the deep water recordings, and wave dispersion from seafloor excitation is important for accurate description of near-field Green's functions. Breakdown of linearity produces substantial misfits for short-wavelength signals in tide gauge recordings with large wave heights. Including the tsunami observations in joint inversions provides improved resolution of near-trench slip compared with inversions of only seismic and geodetic data. Two rupture models, with fine-grid (15 km) and coarse-grid (30 km) spacing, are inverted for the Mentawai event. Stronger regularization is required for the fine model representation. Both models indicate a shallow concentration of large slip near the trench with peak slip of ~15 m. Fully nonlinear forward modeling of tsunami waveforms confirms the validity of these two models for matching the tsunami recordings along with the other data.

  4. Forearc Structure and Fault Slip Near the Epicenter of the April 1, 2007, Megathrust Earthquake (Mw 8.1) and Tsunami in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Fisher, M. A.; Scholl, D. W.; Geist, E. L.; Sliter, R. W.; Wong, F. L.; Reiss, C.; Mann, D. M.

    2007-12-01

    , as indicated by stacked angular disconformities within the basins. Listric normal faults document local collapse of the upper slope that may have been driven by subduction of high-standing oceanic features. Modeling the tsunami produced by the 2007 earthquake indicates that some islands are so close to the epicenter that tsunami waves arrived within 5 min. after shaking began, allowing people scant time to react.

  5. Modeling the ionospheric impact of tsunami-driven gravity waves with SAMI3: Conjugate effects

    NASA Astrophysics Data System (ADS)

    Huba, J. D.; Drob, D. P.; Wu, T.-W.; Makela, J. J.

    2015-07-01

    The Naval Research Laboratory first-principles ionosphere model SAMI3 is used to study the ionospheric effects associated with tsunami-driven gravity waves. Specifically, the Tohoku-Oki tsunami of 11 March 2011 is modeled. It is shown that gravity wave-induced variations in the neutral wind lead to plasma velocity variations both perpendicular and parallel to the geomagnetic field. Moreover, the electric field induced by the neutral wind perturbations can map to the conjugate hemisphere. Thus, electron density variations can be generated in both hemispheres which impact the total electron content (TEC) and 6300 Šairglow emission. It is found that the TEC exhibits variations of ≲ ±0.1 total electron content unit (1 TECU = 1016 el m-2) and the 6300 Šairglow emission variation is up to ˜±2.5% relative to the unperturbed background airglow.

  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. 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.

  8. 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

  9. 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

  10. Recent Tsunami Highlights Need for Awareness of Tsunami Duration

    NASA Astrophysics Data System (ADS)

    Kelly, Annabel; Dengler, Lori A.; Uslu, Burak; Barberopoulou, Aggeliki; Yim, Solomon C.; Bergen, Kristian J.

    2006-12-01

    On Wednesday, 15 November 2006, Crescent City Harbor, in Del Norte County, Calif., was hit by surges resulting from the tsunami generated by the Mw=8.3 Kuril Islands earthquake. The strong currents caused an estimated US $700,000 to $1 million in losses to the small boat basin at Citizen's Dock, destroying or damaging three floating docks and causing minor damage to several boats (Figure 1). The event highlighted a persistent problem for tsunami hazard mitigation: Most people are still unaware that the first tsunami waves rarely are the largest and that the potential for damaging waves may last for many hours.

  11. Field Survey Following the 28 October 2012 Haida Gwaii Tsunami

    NASA Astrophysics Data System (ADS)

    Leonard, L. J.; Bednarski, J. M.

    2014-12-01

    This article documents the near-field effects of the largest tsunami of 2012 (globally), which occurred following Canada's second-largest recorded earthquake, on a thrust fault offshore western Haida Gwaii on October 28 (UTC). Despite a lack of reported damaging waves on the coast of British Columbia (largest amplitudes were recorded in Hawaii), three field surveys in the following weeks and months reveal that much of the remote unpopulated, uninstrumented coastline of western Haida Gwaii was impacted by significant tsunami waves that reached up to 13 m above the state of tide. Runup exceeded 3 m at sites spanning ~200 km of the coastline. Greatest impacts were apparent at the heads of narrow inlets and bays on western Moresby Island, where natural and manmade debris with a clear oceanward origin was found on the forest floor and caught in tree branches, inferring flow depths up to 2.5 m. Bays that see regular exposure to storm waves were generally less affected; at these sites a storm origin cannot be ruled out for the debris surveyed. Logs disturbed from their apparent former footprints on the forest floor at the head of Pocket Inlet provide evidence of complex runup, backwash and oblique flow patterns, as noted in other tsunamis. Discontinuous muddy sediments were found at a few sites; sedimentation was not proportional to runup. Lessons learned from our study of the impacts of the Haida Gwaii tsunami may prove useful to future post-tsunami and paleotsunami surveys, as well as tsunami hazard assessments.

  12. 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

  13. Neural network for tsunami and runup forecast

    NASA Astrophysics Data System (ADS)

    Namekar, Shailesh; Yamazaki, Yoshiki; Cheung, Kwok Fai

    2009-04-01

    This paper examines the use of neural network to model nonlinear tsunami processes for forecasting of coastal waveforms and runup. The three-layer network utilizes a radial basis function in the hidden, middle layer for nonlinear transformation of input waveforms near the tsunami source. Events based on the 2006 Kuril Islands tsunami demonstrate the implementation and capability of the network. Division of the Kamchatka-Kuril subduction zone into a number of subfaults facilitates development of a representative tsunami dataset using a nonlinear long-wave model. The computed waveforms near the tsunami source serve as the input and the far-field waveforms and runup provide the target output for training of the network through a back-propagation algorithm. The trained network reproduces the resonance of tsunami waves and the topography-dominated runup patterns at Hawaii's coastlines from input water-level data off the Aleutian Islands.

  14. 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.

  15. 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.

  16. 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).

  17. 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.

  18. 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.

  19. Effects of the tsunami on fisheries and coastal livelihood: a case study of tsunami-ravaged southern Sri Lanka.

    PubMed

    De Silva, D A M; Yamao, Masahiro

    2007-12-01

    Beyond the death toll, the tsunami of 26 December 2004 crippled many of the livelihood assets (human, social, physical, financial and natural) available to assist those directly affected. Drawing on surveys of three villages in three districts in the south of Sri Lanka, this paper describes the livelihood asset building capacity of the fishing communities. Assessments are also made of the impact of the tsunami on coastal communities and the impact of government policy on rebuilding. A livelihood asset score was calculated for each village by comparing their strengths in capacity building. In all aspects of capital building, including human, social, financial, physical and natural capital, the fishing community in Tangalle was significantly ahead of the fishing communities in Hikkaduwa and Weligama. Experienced fishermen with better educational backgrounds had a significant influence on the capacity building of livelihood assets. Relocation and resettlement plans brought persistent uncertainty to fishermen in Hikkaduwa and Weligama and threatened to disrupt their community bonds and social networks. PMID:18028160

  20. 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

  1. Tsunami Hazards From Strike-Slip Earthquakes

    NASA Astrophysics Data System (ADS)

    Legg, M. R.; Borrero, J. C.; Synolakis, C. E.

    2003-12-01

    Strike-slip faulting is often considered unfavorable for tsunami generation during large earthquakes. Although large strike-slip earthquakes triggering landslides and then generating substantial tsunamis are now recognized hazards, many continue to ignore the threat from submarine tectonic displacement during strike-slip earthquakes. Historical data record the occurrence of tsunamis from strike-slip earthquakes, for example, 1906 San Francisco, California, 1994 Mindoro, Philippines, and 1999 Izmit, Turkey. Recognizing that strike-slip fault zones are often curved and comprise numerous en echelon step-overs, we model tsunami generation from realistic strike-slip faulting scenarios. We find that tectonic seafloor uplift, at a restraining bend or"pop-up" structure, provides an efficient mechanism to generate destructive local tsunamis; likewise for subsidence at divergent pull-apart basin structures. Large earthquakes on complex strike-slip fault systems may involve both types of structures. The California Continental Borderland is a high-relief submarine part of the active Pacific-North America transform plate boundary. Natural harbors and bays created by long term vertical motion associated with strike-slip structural irregularities are now sites of burgeoning population and major coastal infrastructure. Significant local tsunamis generated by large strike-slip earthquakes pose a serious, and previously unrecognized threat. We model several restraining bend pop-up structures offshore southern California to quantify the local tsunami hazard. Maximum runup derived in our scenarios ranges from one to several meters, similar to runup observed from the 1994 Mindoro, Philippines, (M=7.1) earthquake. The runup pattern is highly variable, with local extremes along the coast. We only model the static displacement field for the strike-slip earthquake source; dynamic effects of moving large island or submerged banks laterally during strike-slip events remains to be examined

  2. Tsunami Hazard Assessment in New Zealand Ports and Harbors

    NASA Astrophysics Data System (ADS)

    Borrero, J. C.; Wotherspoon, L.; Power, W. L.; Goring, D.; Barberopoulou, A.; Melville, B.; Shamseldin, A.

    2012-12-01

    The New Zealand Ministry of Science and Innovation (MSI) has sponsored a 3-year collaborative project involving industry, government and university research groups to better assess and prepare for tsunami hazards in New Zealand ports and harbors. As an island nation, New Zealand is highly dependent on its maritime infrastructure for commercial and recreational interests. The recent tsunamis of 2009, 2010 and 2011 (Samoa, Chile and Japan) highlighted the vulnerability of New Zealand's marine infrastructure to strong currents generated by such far field events. These events also illustrated the extended duration of the effects from such tsunamis, with some of the strongest currents and highest water levels occurring many hours, if not days after the tsunami first arrival. In addition, New Zealand also sits astride the Tonga-Kermadec subduction zone, which given the events of recent years, cannot be underestimated as a major near field hazard. This presentation will discuss the modeling and research strategy that will be used to mitigate tsunami hazards in New Zealand ports and harbors. This will include a detailed time-series analysis (including Fourier and discrete Wavelet techniques) of water levels recorded throughout New Zealand form recent tsunami events (2009 Samoa, 2010 Chile and 2011 Japan). The information learned from these studies will guide detailed numerical modeling of tsunami induced currents at key New Zealand ports. The model results will then be used to guide a structural analysis of the relevant port structures in terms of hydrodynamic loads as well as mooring and impact loads due to vessel and/or debris. Ultimately the project will lead to an improvement in New Zealand's tsunami response plans by providing a decision making flow chart, targeted for marine facilities, to be used by emergency management officials during future tsunami events.Tsunami effects at Port Charles, New Zealand: (top) inundation into a neighborhood and (bottom left and right

  3. Assessing of site-related changes of tsunamis impacting closed ocean basins

    NASA Astrophysics Data System (ADS)

    Gallazzi, S.; Tinti, S.; Tonini, R.

    2009-04-01

    Tsunamis are long waves that travel across the ocean and are capable of carrying destructive energy over very long distances. Studying their propagation path and the complex way they interact with local bathymetries is of fundamental importance for predicting their impact on the coast and for hindcast analyses. This work is focussed on the influence of closed sea basins on the tsunami propagation. By closed basins we mean here any basins capable of modifying significantly the tsunami signal with respect to the surrounding open sea. Here two different methodologies are applied to two relevant examples: the Seychelles Island platform, that was impacted by the 2004 Indian Ocean megatsunami, and the Messina Strait, Italy, that was affected by several severe tsunami events, the last one taking place in 1908. In the first case, in the framework of EU- funded SCHEMA (Scenarios for Hazard-induced Emergencies Management) project, through the analysis of synthetic/real tide-gauge records of the 2004 simulated/observed tsunami, it is shown that the deep-ocean Seychelles-platform transition changes the spectral distribution of the tsunami energy with peak signal amplification of selected peaks, which is linked both to the platform bathymetric configuration and to coastal geometry of the islands. The Messina Straits is a sort of a channel connecting the Tyrrhenian sea to the Ionian sea and including some sub-basins, like the Messina harbour. To study the effect of the channel on the tsunami propagation, numerical simulations were used to force the basin along different boundaries with sinusoidal functions having different periods within the range of typical tsunami frequencies. The computed amplification curves show that the main resonance period is approximately 10 minutes all over the Straits, but reveal that the response change from place to place and identify those places that are most sensitive to tsunami attacks.

  4. Effective coastal boundary conditions for tsunami wave run-up over sloping bathymetry

    NASA Astrophysics Data System (ADS)

    Kristina, W.; Bokhove, O.; van Groesen, E.

    2014-09-01

    An effective boundary condition (EBC) is introduced as a novel technique for predicting tsunami wave run-up along the coast, and offshore wave reflections. Numerical modeling of tsunami propagation in the coastal zone has been a daunting task, since high accuracy is needed to capture aspects of wave propagation in the shallower areas. For example, there are complicated interactions between incoming and reflected waves due to the bathymetry and intrinsically nonlinear phenomena of wave propagation. If a fixed wall boundary condition is used at a certain shallow depth contour, the reflection properties can be unrealistic. To alleviate this, we explore a so-called effective boundary condition, developed here in one spatial dimension. From the deep ocean to a seaward boundary, i.e., in the simulation area, we model wave propagation numerically over real bathymetry using either the linear dispersive variational Boussinesq or the shallow water equations. We measure the incoming wave at this seaward boundary, and model the wave dynamics towards the shoreline analytically, based on nonlinear shallow water theory over bathymetry with a constant slope. We calculate the run-up heights at the shore and the reflection caused by the slope. The reflected wave is then influxed back into the simulation area using the EBC. The coupling between the numerical and analytic dynamics in the two areas is handled using variational principles, which leads to (approximate) conservation of the overall energy in both areas. We verify our approach in a series of numerical test cases of increasing complexity, including a case akin to tsunami propagation to the coastline at Aceh, Sumatra, Indonesia.

  5. Source of 1629 Banda Mega-Thrust Earthquake and Tsunami: Implications for Tsunami Hazard Evaluation in Eastern Indonesia

    NASA Astrophysics Data System (ADS)

    Major, J. R.; Liu, Z.; Harris, R. A.; Fisher, T. L.

    2011-12-01

    Using Dutch records of geophysical events in Indonesia over the past 400 years, and tsunami modeling, we identify tsunami sources that have caused severe devastation in the past and are likely to reoccur in the near future. The earthquake history of Western Indonesia has received much attention since the 2004 Sumatra earthquakes and subsequent events. However, strain rates along a variety of plate boundary segments are just as high in eastern Indonesia where the earthquake history has not been investigated. Due to the rapid population growth in this region it is essential and urgent to evaluate its earthquake and tsunami hazards. Arthur Wichmann's 'Earthquakes of the Indian Archipelago' shows that there were 30 significant earthquakes and 29 tsunami between 1629 to 1877. One of the largest and best documented is the great earthquake and tsunami effecting the Banda islands on 1 August, 1629. It caused severe damage from a 15 m tsunami that arrived at the Banda Islands about a half hour after the earthquake. The earthquake was also recorded 230 km away in Ambon, but no tsunami is mentioned. This event was followed by at least 9 years of aftershocks. The combination of these observations indicates that the earthquake was most likely a mega-thrust event. We use a numerical simulation of the tsunami to locate the potential sources of the 1629 mega-thrust event and evaluate the tsunami hazard in Eastern Indonesia. The numerical simulation was tested to establish the tsunami run-up amplification factor for this region by tsunami simulations of the 1992 Flores Island (Hidayat et al., 1995) and 2006 Java (Katoet al., 2007) earthquake events. The results yield a tsunami run-up amplification factor of 1.5 and 3, respectively. However, the Java earthquake is a unique case of slow rupture that was hardly felt. The fault parameters of recent earthquakes in the Banda region are used for the models. The modeling narrows the possibilities of mega-thrust events the size of the one

  6. Tsunami hazard assessment in the Euro-Mediterranean region: outcome of the TRANSFER European project

    NASA Astrophysics Data System (ADS)

    Hébert, Hélène; Roger, Jean; Sahal, Alexandre; Allgeyer, Sébastien; Schindelé, François

    2010-05-01

    The FP6 TRANSFER project (2006-2009) (led by University of Bologna) focused its activities on tsunami hazard assessment for the Euro-Mediterranean area, based on updated databases, tsunami hazard assessment through numerical modeling and propositions of operational tools for warning purposes. Within the project, the activities in CEA were devoted to three main fields. First, the numerical methods have been tested against several benchmark problems which were able to demonstrate the efficiency of the methods used. Then a statistical approach has been proposed to analyze the tsunami variability along shorelines. This study was inferred from the numerous databases gathered after the 2004 Indian Ocean tsunami. First order numerical models have been carried out without grid refinement, compared to available observations and discussed with respect to the well accepted coastal amplification laws (Green, Synolakis). The method thereby defined was finally applied to the Balearic Islands to consider the tsunami threat for earthquake sources originating from northern Africa. The results underline the relative tsunami exposure for the different sections of the coastline for the Balearic Islands. Finally two detailed hazard studies have been conducted in Palma (Majorca, Balearic) and Istanbul (Turkey), based on scenarios of tsunamigenic earthquakes. The results show that the harbour of Palma in Majorca is rather protected from the tsunamis considered in the study (i.e. earthquakes with magnitude 7.0 to 7.3 along northern Africa), whereas the southeastern coastline of Majorca seems to be more significantly exposed. In Istanbul, for the given scenarios (earthquakes with magnitude 7.1 to 7.4 in the Sea of Marmara), the tsunami exposure is more important for several coastal low-lying sites where inundations can occur. Beyond these results, the project also gave the opportunity to refine databases of tsunami observations in France, namely for the 2003 tsunami triggered by the Mw 6

  7. Modeling of the 2011 Tohoku-oki Tsunami and its Impacts on Hawaii

    NASA Astrophysics Data System (ADS)

    Cheung, K.; Yamazaki, Y.; Roeber, V.; Lay, T.

    2011-12-01

    aftermath. The model results provide insights into effects of fringing reefs, which are present along 70% of Hawaii's coastlines, on tsunami transformation and runup processes. This case study improves our understanding of tsunamis in tropical island environment and validates the modeling capability to predict their impacts for hazard mitigation and emergency management.

  8. 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

  9. 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.

  10. Effect of Tsunamis generated in the Manila Trench on the Gulf of Thailand

    NASA Astrophysics Data System (ADS)

    Ruangrassamee, Anat; Saelem, Nopporn

    2009-09-01

    Tsunamis generated in the Manila Trench can be a threat to Thailand. Besides runup of tsunamis along the eastern coast, infrastructures in the Gulf of Thailand, for example, gas pipelines and platforms can be affected by tsunamis. In this study, the simulation of tsunamis in the Gulf of Thailand is conducted. Six cases of fault ruptures in the Manila trench are considered for earthquakes with magnitudes of 8.0, 8.5, and 9.0. The linear shallow water wave theory in spherical coordinate system is used for tsunami simulation in the large area covering Southeast Asia while the nonlinear shallow water wave theory in Cartesian coordinate system is used for tsunami simulation in the Gulf of Thailand. It is found that tsunamis reach the southern part of Thailand in 13 h after an earthquake and reach Bangkok in 19 h. The tsunami amplitude is largest in the direction towards the Philippines and Vietnam. The southern part of China is also severely affected. The Gulf of Thailand is affected by the diffraction of tsunamis around the southern part of Vietnam and Cambodia. The tsunami amplitude at the southernmost coastline is about 0.65 m for the M w 9.0 earthquake. The current velocity in the Gulf of Thailand due to the M w 9.0 earthquake is generally less than 0.2 m/s.

  11. A tsunami early warning system and tsunami source propagation

    NASA Astrophysics Data System (ADS)

    Hirata, K.

    2008-12-01

    The present-day's tsunami early warning systems (TEWSs) assume that a tsunami source is created instantaneously over the whole source area. However, finite rupture propagation speeds reasonably affect tsunami generation and propagation. Travel times of the first tsunami waves generated from rupture propagation fault models have to arrive later at some regions than those from instantaneous fault models but do not arrive faster everywhere [e.g., Neetsu et al., 2005]. On the other hand, the effect of earthquake rupture propagation on tsunami amplitude has scarcely investigated based on real bathymetry, although it had studied under flat ocean assumption [Aida, 1969; Yamashita and Sato, 1974]. We investigated it for regional tsunamis (travel distance between 5deg and 30 deg) by using real bathymetry in terms of numerical simulation. The grid size is 3 minutes of arc, interpolated from ETOPO2 [Smith and Sandwell, 1997]. A constant amount of slip was given on each subfault. Other subfault parameters are the same as Hirata et al.[2006]. Effect on the first upward wave amplitudes of offshore tsunamis is summarized as follows; (1) The slower the rupture velocity, the larger the increasing rate of the tsunami wave amplitude. For instance, in the offshore of the east coast of Sri Lanka, the 1st tsunami amplitude increases 10% at the rupture velocity of 3.5 km/sec, 14 % at 2.5 km/sec, 23% at 1.5 km/sec, and 38% at 1.0 km/sec in the case of 500km-long fault. This indicates that the rupture propagation effect on regional tsunami amplitude is large in the cases of slow earthquakes. (2) Increasing (or decreasing) rate in tsunami amplitude due to the rupture propagation is not necessarily larger in longer fault than shorter fault. In other words, even in the case of a short fault, say a few hundred kilometers, the effect of the rupture propagation on tsunami amplitude may not be neglected. This is because the increasing (or decreasing) rate in tsunami amplitude is related to

  12. Tsunami: ocean dynamo generator.

    PubMed

    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

  13. 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.

  14. Tsunami hazard map in eastern Bali

    NASA Astrophysics Data System (ADS)

    Afif, Haunan; Cipta, Athanasius

    2015-04-01

    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.

  15. 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.

  16. 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

  17. Validation of NEOWAVE with Measurements from the 2011 Tohoku Tsunami

    NASA Astrophysics Data System (ADS)

    Cheung, K.; Yamazaki, Y.

    2012-12-01

    and the Hawaiian Island chain. These coastlines include shallow embayments with open plains, narrow estuaries with steep cliffs, and volcanic insular slopes with fringing reefs for full validation of the model in a single event. The Tohoku tsunami caused persistent oscillations and hazardous currents in coastal waters around Hawaii. Analysis of the computed surface elevation reveals complex resonance modes along the Hawaiian Island chain. Standing waves with period 16 min or shorter are able to form a series of nodes and antinodes over the reefs that results in strong currents and large drawdown responsible for the damage in harbors and marinas. The results provide insights into effects of fringing reefs, which are present along 70% of Hawaii's coastlines, on tsunami transformation and runup processes. The case study improves our understanding on tsunamis in tropical island environments and validates the modeling capability to predict their impacts for hazard mitigation and emergency management.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. Fragility curves for structural damage by the 1993 Okushiri tsunami

    NASA Astrophysics Data System (ADS)

    Koshimura, S.

    2009-12-01

    In 1993, the tsunami accompanied with the M7.8 earthquake off the south-west coast of Hokkaido, Japan attacked Okushiri island, which locates 30 km west of Hokkaido, within 5 minutes after the quake and caused more then 200 casualties. Especially, Aonae district in the southern most area of Okushiri island suffered devastating damage by approximately 11 m tsunami attacking from the west coast of the island and the fire caused during and after the tsunami attack. After the event occurred, extensive field survey was conducted to measure the tsunami run-up height, extent of inundation zone and damage. The tsunami damage, structural damage and casualty, and tsunami run-up heights in Aonae district are summarized by the survey teams, e.g. Shuto and Matsutomi (1995). However, the relations between the tsunami hazard and structural damage have never been discussed. Recently, we developed a methodology to identify the relationships between tsunami hazard and the damage occurred in the 2004 Sumatra-Andaman earthquake tsunami by using the advances of tsunami numerical modeling, remote sensing and GIS analysis, to construct fragility curves to identify structural damage probabilities with particular regard to the tsunami hydrodynamics (Koshimura et al., 2009). Following that procedure, the present research aims to revisit the 1993 Okushiri tsunami disaster and identify the relationships between the tsunami hazard and the structural damage, that has never been discussed in the earlier studies. First, we reproduce the 1993 Okushiri tsunami by the numerical modeling with high-resolution topography data obtained through the recent Realtime-Kinematic GPS measurement to reproduce the pre-tsunami topographic condition. Second, we interpret the structural damage using visual inspection of aerial photos acquired before and after the tsunami. Third, both of tsunami hazard and damage information are correlated by GIS analysis. As a result, the relations between tsunami hazard and

  3. 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.

  4. Lost tsunami

    NASA Astrophysics Data System (ADS)

    Pareschi, Maria Teresa; Boschi, Enzo; Favalli, Massimiliano

    2006-11-01

    Numerical simulations support the occurrence of a catastrophic tsunami impacting all of the eastern Mediterranean in early Holocene. The tsunami was triggered by a debris avalanche from Mt. Etna (Sicily, Italy) which entered the Ionian Sea in the order of minutes. Simulations show that the resulting tsunami waves were able to destabilize soft marine sediments across the Ionian Sea floor. This generated the well-known, sporadically located, ``homogenite'' deposits of the Ionian Sea, and the widespread megaturbidite deposits of the Ionian and Sirte Abyssal Plains. It is possible that, ~8 ka B.P., the Neolithic village of Atlit-Yam (Israel) was abandoned because of impact by the same Etna tsunami. Two other Pleistocenic megaturbidite deposits of the Ionian Sea can be explained by previous sector collapses from the Etna area.

  5. 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.

  6. 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

  7. 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

  8. Numerical simulation of tsunami generation by pryoclastic flow at Aniakchak Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.; Watts, P.

    2003-01-01

    Pyroclastic flows entering the sea are plausible mechanisms for tsunami generation at volcanic island arcs worldwide. We evaluate tsunami generation by pyroclastic flow using an example from Aniakchak volcano in Alaska where evidence for tsunami inundation coincident with a major, caldera-forming eruption of the volcano ca. 3.5 ka has been described. Using a numerical model, we simulate the tsunami and compare the results to field estimates of tsunami run up.

  9. 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

  10. 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

  11. Field Survey of Tsunami Effects in Sri Lanka due to the Sumatra-Andaman Earthquake of December 26, 2004

    NASA Astrophysics Data System (ADS)

    Inoue, Shusaku; Wijeyewickrema, Anil C.; Matsumoto, Hiroyuki; Miura, Hiroyuki; Gunaratna, Priyantha; Madurapperuma, Manoj; Sekiguchi, Toru

    2007-03-01

    The December 26, 2004 Sumatra-Andaman earthquake that registered a moment magnitude (M w ) of 9.1 was one of the largest earthquakes in the world since 1900. The devastating tsunami that resulted from this earthquake caused more casualties than any previously reported tsunami. The number of fatalities and missing persons in the most seriously affected countries were Indonesia - 167,736, Sri Lanka - 35,322, India - 18,045 and Thailand - 8,212. This paper describes two field visits to assess tsunami effects in Sri Lanka by a combined team of Japanese and Sri Lankan researchers. The first field visit from December 30, 2004 January 04, 2005 covered the western and southern coasts of Sri Lanka including the cities of Moratuwa, Beruwala, Bentota, Pereliya, Hikkaduwa, Galle, Talpe, Matara, Tangalla and Hambantota. The objectives of the first field visit were to investigate the damage caused by the tsunami and to obtain eyewitness information about wave arrival times. The second field visit from March 10 18, 2005 covered the eastern and southern coasts of Sri Lanka and included Trincomalee, Batticaloa, Arugam Bay, Yala National Park and Kirinda. The objectives of the second visit were mainly to obtain eyewitness information about wave arrival times and inundation data, and to take relevant measurements using GPS instruments.

  12. Tsunami Sediment Transport and Deposition in a Sediment Limited Environment on American Samoa

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    On 29 September 2009 a large tsunami struck the US territory of American Samoa, killing 34 people. However, had it not been for the island’s tsunami preparation, the death toll would have been much higher. An integral part of preparing for a tsunami is knowing how often large tsunamis occur, knowledge that can be improved by using paleo-tsunami sediment deposits to lengthen the historical tsunami record. Doing so requires a detailed understanding of the processes that control sediment transport during tsunamis and thus the patterns of deposition, which may vary substantially in sediment limited and sediment rich environments. As American Samoa is relatively young and composed of volcanic islands surrounded by coral reefs, sandy beaches occur primarily as pocket beaches between volcanic rock headlands. The extent and depth of littoral sediment available for transport is therefore limited. This is in contrast to previous studies which have focused primarily on coastal environments with extensive sand supply. Here, field observations and a numerical model are used to investigate tsunami-induced sediment transport in two sediment limited embayments (Massacre and Fagafue Bays) on the north side of the island of Tutuila in American Samoa. Detailed measurements of bathymetry, topography, tsunami flow depth and direction, sediment deposition, reef and vegetative roughness, and the extent of sediment available for transport were collected approximately two weeks after the tsunami. Both embayments contain sandy sediments that extend all the way (Massacre Bay) and part of the way (Fagafue Bay) along the beach at the head of the embayment. The observed onshore sediment deposit created by the tsunami was limited and patchy in both embayments even though a number of large coral boulders were transported onshore at both locations. The extent to which the limited supply of sediment plays in producing the patterns of deposition observed in these two bays is examined using a three

  13. Tsunami Observations in Rivers from a Perspective of Tsunami Interaction with Tide and Riverine Flow

    NASA Astrophysics Data System (ADS)

    Tolkova, Elena; Tanaka, Hitoshi; Roh, Min

    2015-03-01

    The observations of the 2011 Tohoku tsunami and the 2010 Chilean tsunami in several rivers in Japan and in the Columbia River in the USA are analyzed for patterns of tsunami behavior in river environments. Tsunamis in rivers exhibit actions very different from those observed on an open coast, but very similar among different rivers, though the action scale in different rivers varies greatly. We describe two tsunami effects in rivers as observed in field data. First, the river tide modulates the tsunami wave in a very specific way common to all rivers. Second, a strong near-field tsunami can cause significant prolonged water accumulation in lower river reaches. Both effects are inherent in tidal river environments, and have been reproduced numerically in a simplified 1-D river using a non-linear, shallow-water model with bottom friction. The numerical experiments highlight the indispensable role of a tsunami's interaction with tide and riverine flow.

  14. 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

  15. 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.

  16. Observations and Impacts from the 2010 Chilean and 2011 Japanese Tsunamis in California (USA)

    NASA Astrophysics Data System (ADS)

    Wilson, Rick I.; Admire, Amanda R.; Borrero, Jose C.; Dengler, Lori A.; Legg, Mark R.; Lynett, Patrick; McCrink, Timothy P.; Miller, Kevin M.; Ritchie, Andy; Sterling, Kara; Whitmore, Paul M.

    2013-06-01

    The coast of California was significantly impacted by two recent teletsunami events, one originating off the coast of Chile on February 27, 2010 and the other off Japan on March 11, 2011. These tsunamis caused extensive inundation and damage along the coast of their respective source regions. For the 2010 tsunami, the NOAA West Coast/Alaska Tsunami Warning Center issued a state-wide Tsunami Advisory based on forecasted tsunami amplitudes ranging from 0.18 to 1.43 m with the highest amplitudes predicted for central and southern California. For the 2011 tsunami, a Tsunami Warning was issued north of Point Conception and a Tsunami Advisory south of that location, with forecasted amplitudes ranging from 0.3 to 2.5 m, the highest expected for Crescent City. Because both teletsunamis arrived during low tide, the potential for significant inundation of dry land was greatly reduced during both events. However, both events created rapid water-level fluctuations and strong currents within harbors and along beaches, causing extensive damage in a number of harbors and challenging emergency managers in coastal jurisdictions. Field personnel were deployed prior to each tsunami to observe and measure physical effects at the coast. Post-event survey teams and questionnaires were used to gather information from both a physical effects and emergency response perspective. During the 2010 tsunami, a maximum tsunami amplitude of 1.2 m was observed at Pismo Beach, and over 3-million worth of damage to boats and docks occurred in nearly a dozen harbors, most significantly in Santa Cruz, Ventura, Mission Bay, and northern Shelter Island in San Diego Bay. During the 2011 tsunami, the maximum amplitude was measured at 2.47 m in Crescent City Harbor with over 50-million in damage to two dozen harbors. Those most significantly affected were Crescent City, Noyo River, Santa Cruz, Moss Landing, and southern Shelter Island. During both events, people on docks and near the ocean became at risk to

  17. 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

  18. 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. PMID:24349889

  19. 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

  20. 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 "tsunami" brings to mind one…

  1. 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. PMID:26392615

  2. 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

  3. Tsunami focusing

    NASA Astrophysics Data System (ADS)

    Spillane, M. C.; Titov, V. V.; Moore, C. W.; Aydin, B.; Kanoglu, U.; Synolakis, C. E.

    2010-12-01

    Tsunamis are long waves generated by impulsive disturbances of the seafloor or coastal topography caused by earthquakes, submarine/subaerial mass failures. They evolve substantially through three dimensional - 2 spatial+1 temporal - spreading as the initial surface deformation propagates. This is referred to as its directivity and focusing. A directivity function was first defined by Ben-Menahem (1961, Bull. Seismol. Soc. Am. 51, 401-435) using the source length and the rupture velocity. Okal (2003, Pure Appl. Geophys. 160, 2189-2221) discussed the details of the analysis of Ben-Menahem (1961) and demonstrated the distinct difference between the directivity patterns of landslide and earthquake generated tsunamis. Marchuk and Titov (1989, Proc. IUGG/IOC International Tsunami Symposium, July 31 - August 3, 1989, Novosibirsk, USSR. p.11-17) described the process of tsunami focusing for a rectangular initial deformation combining positive and negative surface displacements. They showed the existence of a focusing point where abnormal tsunami wave height can be registered. Here, first, we describe and quantify numerically tsunami focusing processes for a combined positive and negative - N-wave type - strip source representing the 17 July 1998 Papua New Guinea and 17 July 2006 Java events. Specifically, considering field observations and tsunami focusing, we propose a source mechanism for the 17 July 2006 Java event. Then, we introduce a new analytical solution for a strip source propagating over a flat bottom using the linear shallow-water wave equation. The analytical solution of Carrier and Yeh (2005, Computer Modeling In Engineering & Sciences, 10(2), 113-121) appears to have two drawbacks. One, the solution involves singular complete elliptic integral of the first kind which results in a self-similar approximate solution for the far-field at large times. Two, only the propagation of Gaussian shaped finite-crest wave profiles can be modeled. Our solution is not only

  4. Could a 1755-like tsunami reach the French Atlantic coastline? Constraints from 20th century observations and numerical modeling.

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    The tsunami generated by the 1st November 1755 (Mw ~8.5) earthquake off Portugal affected mainly the coasts of the Iberian Peninsula and Northwest Morocco, and was observed in some places on the North Atlantic coasts, towards the West Indies, but also towards Ireland and the Great Britain, in Cornwall. However, no evidence of observation were found along French Atlantic coastline so far. In a first step, to determine whether there could be effects due to tsunamis on the French coastline, we conducted a study to search for actual tsunamis signals in all historical tide gauge stations of the French Atlantic coast available during the 20th century, specifically for the 1969 and 1975 tsunamis that were well observed in Portugal. Because many recordings are available from the French Hydrographic Service in La Rochelle (west French Atlantic coastline), we focus our study on this harbor. The analysis of these historical tide gauge data shows no evidence for tsunamis in La Rochelle, neither in 1969 or in 1975. Then, to confirm this lack of tsunami, we simulate the tsunamis from the 1969 and 1975 sources, using non linear shallow water equations and a series of imbricated bathymetric grids focusing to the French coastline, and then towards the harbor of La Rochelle: the modeling results confirm unnoticeable amplitudes. In the following step, tsunamis from three different scenarios for the 1755 earthquake have been similarly modeled to estimate the impact of such a tsunami on the French Atlantic coast, with a focus on La Rochelle harbor. The results show that, while the harbor is well protected (amplitudes computed on a synthetic tide gage in the harbor do not exceed 20 to 30 cm crest-to-trough) several areas may have undergone a more important, yet moderate impact, from 0.5 to 1 m, especially in the western part of the island of Ré and the northern coast of the island of Oléron. This may have caused possible local inundations in lowland areas, all the more since the tide

  5. Application of heavy minerals analysis in studies of tsunami deposits

    NASA Astrophysics Data System (ADS)

    Jagodziński, R.; Sternal, B.; Szczuciński, W.

    2012-04-01

    Tsunami deposits are very important for assessment of tsunami hazard. However, their identification is often difficult because they are depended on many factors and there is no unique set of features, which could be applied. The presence of heavy minerals (HM) have been frequently noted in tsunami deposits, however, so far they were little studied in detail. The HM analyses may be useful in finding the sediment provenance (e.g. marine), and trends (vertical and spatial) in HM assemblages within the tsunami deposits resulting from hydraulic sorting processes that had been acting during the tsunami. To test usefulness of HM analysis in tsunami deposits studies the modern tsunami deposits left by 2004 Indian Ocean tsunami on Kho Khao Island, Thailand (details in Jagodziński et al. 2009), and by 2011 Tohoku-oki tsunami on Sendai plain, Japan, were studied. The HM fraction content and mineral assemblages significantly differs between the two studied cases. Tsunami deposits from 2004 tsunami contained only ~ 1.7 % of HM and 99 % of them were tourmalines, micas, limonites, zircon and opaque minerals. The Tohoku-oki tsunami deposits were composed on average in 34 % from HM. They were in 97 % represented by amphiboles, pyroxenes and opaque minerals. The HM assemblages of 2004 tsunami were different from beach sediments and pre-tsunami soils, and were partly derived from marine sediments. Moreover, observed variations within HM suit, in particular in share of flake-shaped micas, reflected sedimentation from suspension by particular waves. The HM analyses of Tohoku-oki tsunami deposits revealed no significant difference between tsunami deposits, beach sediments and pre-tsunami soils. It suggested that the contribution of marine sediments may be very small, as suggested also by micropaleontological studies. There is also no regular trend within tsunami deposits apart from steady landward decrease of HM fraction content. The HM analysis may be useful supplementary tool in

  6. 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

  7. 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.

  8. Investigation of Hawai'i Tsunami Boulder Deposits to Assess Caribbean Tsunami Hazards

    NASA Astrophysics Data System (ADS)

    Watt, S.; Jaffe, B. E.; Richmond, B. M.; Gelfenbaum, G.; Morton, R. A.; Buckley, M.

    2008-12-01

    Assessing tsunami hazard for islands in the Caribbean from on land coarse-clast sedimentary deposits is challenging because the deposits can be formed by extreme-waves from either hurricanes or tsunamis and because a recent tsunami analog is lacking. In order to discriminate the type of extreme-wave event or combination of events that produced deposits in the Caribbean, it is necessary to map and analyze deposits of unequivocal origin for comparison. The southeastern shore of the island of Hawai'i has been impacted by both storms and tsunamis over the last century and is an ideal location to study deposits produced by extreme-wave events. Locally generated tsunamis in 1868 and 1975 produced scattered gravel, boulder, and sand deposits up to several hundred meters inland. The deposits overlie basalt flows as recent as 1973. No other major tsunamis have impacted the southeastern shore of Hawai'i since. The analysis of the southeastern Hawai'i extreme-wave deposits will provide useful criteria for differentiating between storm and tsunami deposits. These data will be compared to boulder, gravel field and sand deposits at Boca Olivia, Bonaire in the Netherlands Antilles in order to improve tsunami risk assessment in the Caribbean.

  9. 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.

  10. Study of recent tsunamis sheds light on earthquakes

    NASA Astrophysics Data System (ADS)

    Satake, Kenji

    In the space of one year, three major destructive tsunamis, or seismic sea waves, devastated coastal regions of Nicaragua (September 2, 1992), Flores Island, Indonesia (December 12, 1992), and Hokkaido, Japan (July 12, 1993). The maximum run-up heights of each of these tsunamis were more than 10 m, and a total of about 1500 people were killed. Field surveys were made for these tsunamis and reported in Eos [Satake et al., 1993; Yeh et al., 1993; Hokkaido Tsunami Survey Team, 1993]. The survey teams, typically consisting of scientists and engineers from various fields, documented the behavior of the tsunamis in detail. Tsunami survey data are used for various types of research, ranging from coastal behavior of tsunamis to past and future earthquakes.

  11. A Methodology for Near-Field Tsunami Inundation Forecasting

    NASA Astrophysics Data System (ADS)

    Gusman, A. R.; Tanioka, Y.

    2014-12-01

    Here we describe a new methodology for near-field tsunami inundation forecasting. We designed an algorithm that can produce high-resolution tsunami inundation maps of near-field sites before the actual tsunami hits the shore. This algorithm relies on a database of precomputed tsunami waveforms at several near-shore points and precomputed tsunami inundation maps from various earthquake fault model scenarios. By using numerical forward model, it takes several hours to simulate tsunami inundation in each site from each fault model. After information about a tsunami source is estimated, tsunami waveforms at near-shore points can be simulated in real-time. A scenario that gives the most similar tsunami waveforms is selected as the site-specific best scenario and the tsunami inundation from that scenario is selected as the tsunami inundation forecast. To test the algorithm, tsunami inundation along the Sanriku coast is forecasted by using source models for the 2011 Tohoku earthquake estimated from GPS, W phase, or offshore tsunami waveform data. The forecasting algorithm is capable of providing a tsunami inundation forecast that is similar to that obtained by numerical forward modeling, but with remarkably smaller CPU time. The time required to forecast tsunami inundation in 15 coastal sites from the Sendai Plain to Miyako City is approximately 3 minutes after information about the tsunami source is obtained. We found that the tsunami inundation forecasts from the 5-min GPS, 10-min W phase fault models, and 35-min tsunami source model are all reliable for tsunami early warning purposes and quantitatively match the observations well, although the latter model gives tsunami forecasts with highest overall accuracy. We evaluated the effectiveness of this algorithm in the real world by carrying out a tsunami evacuation drill in Kushiro City, Hokkaido, Japan, involving the city residents. The participants found that the use of the tsunami inundation forecast map produced by

  12. Numerical modelling of potential submarine landslides and generated tsunami in Sumatra

    NASA Astrophysics Data System (ADS)

    Fernandez-Nieto, E.; Mangeney, A.; Singh, S. C.; Chauhan, A.; Bouchut, F.; Castro Díaz, M.

    2010-12-01

    Recent studies suggests that tsunami risk along the SW coast of Sumatra could be due to co-seismic slip along a backthrust at the NE Margin of the Mentawai Island and associated landslides (Singh et al., 2010). Using a combination of high-resolution seismic reflection and bathymetry data, they observed deposits of large submarine landslides at the NE margin of Mentawai Island and suggest that the high wave that occurred in 1797 might have been enhanced by landslides, producing a large localised tsunami. Until now most of the work devoted to tsunami hazard assessment in the area of Sumatra Island focussed on megaearthquakes earthquakes generated tsunamis. Therefore, estimating the run up heights due to submarine landslides is essential for risk mitigation along the SW coast of Sumatra. A series of numerical scenarios are performed here to simulate potential submarine landslides and generated tsunamis in the area of Sumatra Island. The height and velocity of the water wave and the impact zones are calculated using a new numerical model solving the depth-averaged shallow water equations with high order finite volume methods. This model corresponds to the 2D extension of the model developed by Fernández-Nieto et al., 2008. The fluidized mass is modeled using a generalization of the Savage-Hutter model [Savage and Hutter, 1989] by including the role of buoyancy and fluid into the thin-layer equations with a Coulomb-type friction law. Our model takes into account the coupling between the fluid and the landslides and incorporates the rigorous description of topography effects that play a key role in the dynamics of landslides. We study the magnitude of variation of the wave expected depending on the location and volume released. These results shows that landslide generated tsunamis have to be taken into account for risk assessment in the area of Sumatra Island. E.D. Fernández-Nieto, F. Bouchut, D. Bresch, M.J. Castro, A. Mangeney, 2008. A new Savage-Hutter type model

  13. 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

  14. 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.

  15. Can Aerosol Offset Urban Heat Island Effect?

    NASA Astrophysics Data System (ADS)

    Jin, M. S.; Shepherd, J. M.

    2009-12-01

    The Urban Heat Island effect (UHI) refers to urban skin or air temperature exceeding the temperatures in surrounding non-urban regions. In a warming climate, the UHI may intensify extreme heat waves and consequently cause significant health and energy problems. Aerosols reduce surface insolation via the direct effect, namely, scattering and absorbing sunlight in the atmosphere. Combining the National Aeronautics and Space Administration (NASA) AERONET (AErosol RObotic NETwork) observations over large cities together with Weather Research and Forecasting Model (WRF) simulations, we find that the aerosol direct reduction of surface insolation range from 40-100 Wm-2, depending on seasonality and aerosol loads. As a result, surface skin temperature can be reduced by 1-2C while 2-m surface air temperature by 0.5-1C. This study suggests that the aerosol direct effect is a competing mechanism for the urban heat island effect (UHI). More importantly, both aerosol and urban land cover effects must be adequately represented in meteorological and climate modeling systems in order to properly characterize urban surface energy budgets and UHI.

  16. Diverse Approaches USED to Characterize the Earthquake and Tsunami Hazards Along the Southern Alaska Continental Margin

    NASA Astrophysics Data System (ADS)

    Haeussler, P. J.; Witter, R. C.; Liberty, L. M.; Brothers, D. S.; Briggs, R. W.; Armstrong, P. A.; Freymueller, J. T.; Parsons, T.; Ryan, H. F.; Lee, H. J.; Roland, E. C.

    2014-12-01

    Earthquakes and tsunamis are the principal geohazards of southern Alaska. The entire margin has ruptured in megathrust earthquakes, including the M9.2 1964 event, and these earthquakes have launched deadly local and trans-Pacific tsunamis. Tsunamis have been by far the largest killer in these earthquakes. Moreover, the subduction zone displays a range in locking behavior from completely locked beneath Prince William Sound, to ­­­­nearly freely slipping beneath the Shumagin Islands. Characterizing earthquake-related tsunami sources requires a diverse set of methods, and we discuss several examples. One important source for tsunamis is from megathrust splay faults. The Patton Bay splay fault system ruptured during the 1964 earthquake and generated a tsunami that impacted coastlines tens of minutes after the earthquake. A combination of multibeam mapping, high-resolution and crustal-scale seismic data, thermochronology, and detrital zircon geochronology show focused exhumation along this splay fault system for the last 2-3 Ma. Moreover, this long term pattern of exhumation mimics the pattern of uplift in 1964. Submarine landslides are another example of a tsunami source. Numerous devastating slides were triggered by the 1964 earthquake. Multibeam bathymetry, bathymetry difference maps, high-resolution seismic data, and records of paleotsunamis in coastal marshes reveal a long history of submarine landsliding in the coastal fjords of Alaska. The Little Ice Age appears to have had a significant influence on the submarine landslides in the 1964 earthquake through increased sediment production, transport to fjord margins, and, locally, compaction by glacier advances. Glacial retreat before 1964 gave rise to over-steepened slopes susceptible to dynamic failure. Numerous blocks in the submarine landslides were particularly effective in generating high tsunami run up. Finally, regional tectonic displacements of the seafloor have launched trans-Pacific tsunamis. Coastal

  17. Tsunami lung.

    PubMed

    Inoue, Yoshihiro; Fujino, Yasuhisa; Onodera, Makoto; Kikuchi, Satoshi; Shozushima, Tatsuyori; Ogino, Nobuyoshi; Mori, Kiyoshi; Oikawa, Hirotaka; Koeda, Yorihiko; Ueda, Hironobu; Takahashi, Tomohiro; Terui, Katsutoshi; Nakadate, Toshihide; Aoki, Hidehiko; Endo, Shigeatsu

    2012-04-01

    We encountered three cases of lung disorders caused by drowning in the recent large tsunami that struck following the Great East Japan Earthquake. All three were females, and two of them were old elderly. All segments of both lungs were involved in all the three patients, necessitating ICU admission and endotracheal intubation and mechanical ventilation. All three died within 3 weeks. In at least two cases, misswallowing of oil was suspected from the features noted at the time of the detection. Sputum culture for bacteria yielded isolation of Stenotrophomonas maltophilia, Legionella pneumophila, Burkholderia cepacia, and Pseudomonas aeruginosa. The cause of tsunami lung may be a combination of chemical induced pneumonia and bacterial pneumonia. PMID:22057370

  18. Tsunami early warning in the central Mediterranean: effect of the heterogeneity of the seismic source on the timely detectability of a tsunami

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    The central Mediterranean, and in particular the coasts of southern Italy, is one of the areas with the highest tsunami hazard in Europe. Limiting our attention to earthquake-generated tsunamis, the sources of historical events hitting this region, as well as the largest part of the potential tsunamigenic seismic sources mapped there, are found at very short distances from the closest shorelines, reducing the time needed for the tsunami to attack the coasts themselves to few minutes. This represents by itself an issue from the Tsunami Early Warning (TEW) perspective. To make the overall problem even more intriguing and challenging, it is known that large tsunamigenic earthquakes are generally characterized by highly heterogeneous distributions of the slip on the fault. This feature has been recognized clearly, for instance, in the giant Sumatra 2004, Chile 2010, and Japan 2011 earthquakes (magnitude 9.3, 8.8 and 9.0, respectively), but it was a property also of smaller magnitude events occurred in the region considered in this study, like the 28 December 1908 Messina Straits tsunamigenic earthquake (M=7.2). In terms of tsunami impact, the parent fault slip heterogeneity usually determines a high variability of run-up and inundation on the near-field coasts, which further complicates the TEW problem. The information on the details of the seismic source rupture coming from the seismic (and possibly geodetic) networks, though of primary importance, is typically available after a time that is comparable or larger than the time comprised between the generation and the impact of the tsunami. In the framework of the EU-FP7 TRIDEC Project, we investigate how a proper marine sensors coverage both along the coasts and offshore can help posing constraints on the characteristics of the source in near-real time. Our approach consists in discussing numerical tsunami scenarios in the central Mediterranean involving different slip distributions on the parent fault; the

  19. 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

  20. Improved landslide-tsunami prediction: Effects of block model parameters and slide model

    NASA Astrophysics Data System (ADS)

    Heller, Valentin; Spinneken, Johannes

    2013-03-01

    Subaerial landslide-tsunamis and impulse waves are caused by mass movements impacting into a water body, and the hazards they pose have to be reliably assessed. Empirical equations developed with physical Froude model studies can be an efficient method for such predictions. The present study improves this methodology and addresses two significant shortcomings in detail for the first time: these are the effect of three commonly ignored block model parameters and whether the slide is represented by a rigid block or a deformable granular material. A total of 144 block slide tests were conducted in a wave flume under systematic variation of three important block model parameters, the slide Froude number, the relative slide thickness, and the relative slide mass. Empirical equations for the maximum wave amplitude, height, and period as well as their evolution with propagation distance are derived. For most wave parameters, remarkably small data scatter is achieved. The combined influence of the three block model parameters affects the wave amplitude and wave height by up to a factor of two. The newly derived equations for block slides are then related to published equations for granular slides. This comparison reveals that block slides do not necessarily generate larger waves than granular slides, as often argued in the technical literature. In fact, it is shown that they may also generate significant smaller waves. The new findings can readily be integrated in existing hazard assessment methodologies, and they explain a large part of the discrepancy between previously published data.

  1. 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. PMID:26392620

  2. 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

  3. 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.

    2016-05-01

    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

  4. The 17 July 2006 Tsunami Along the South Coast of Java, Indonesia: Field Survey and Near Field Tsunami Simulation

    NASA Astrophysics Data System (ADS)

    Lavigne, F.; Gomez, C.; Hebert, H.; Sladen, A.; Schindele, F.; Mardiatno, D.; Priyono, J.; Giffo, M.; Wassmer, P.

    2006-12-01

    The 17th July 2006, a tsunami struck the southern coast of Java, Indonesia. The triggering earthquake at 15:19 WIB was located about 200 km south from Pangandaran (9°24S-117°36E), with a magnitude reaching M_w = 7.7. In order to calibrate numerical models, field surveys were conducted by a team divided into threee groups - from the French CNRS and the Indonesian Research Center for Disasters - from Pangandaran district in West Java to Gunungkidul district in Central Java. The surveys began the day after the tsunami and lasted more than one month. Data collection involved measurements of the wave height and runup, inundation depth, flow direction, and chronology of the tsunami event. Two main waves were reported by eyewitnesses' accounts. The second wave reached locally 8 to 11 m high before its breaking at several sites. Depending on the nearshore topography, this wave broke either nearshore, on the beaches or up to 100 meters inland. Local runups up to 15 m asl were measured on cliffs at Nusa Kambangan Island. Inundation depth usually ranged 2 to 3 m from ground. The tsunami arrival time has been recorded precisely at several locations owing to good recorders: a clock which stopped working when struck by the tsunami, pictures taken by testimonies, or a video movie at the Cilacap power plant construction. The first wave reached the whole coast between Pangandaran and pantai Ayah between 16:15 and 16:20 WIB, one hour after the earthquake. Further East, Baron Beach in Central Java was struck around 16:30 WIB, and the tide gauge at Benoa (Bali) recorded the tsunami at 17:00 WIB. We discuss the source of the tsunami in trying several seismological models used to trigger the waves and compute their impact onland. We particularly stress on the tsunami effect in the Cilacap area where detailed bathymetric and topographic data have been used to refine the modeling. When compared to the high amplitudes measured, the results provide indications on the most realistic source

  5. 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.

  6. Near-field tsunami forecasting using offshore tsunami data from the 2011 Tohoku earthquake

    NASA Astrophysics Data System (ADS)

    Tsushima, H.; Hayashi, Y.; Hirata, K.; Baba, T.; Ohta, Y.; Iinuma, T.; Hino, R.; Tanioka, Y.; Sakai, S.; Shinohara, M.; Kanazawa, T.; Maeda, K.

    2012-12-01

    Real-time tsunami forecasting is one of the effective ways to mitigate tsunami disasters. Transmission of a tsunami warning based on rapid and accurate tsunami forecasting to coastal communities helps the residents to make the decisions about their evacuation behaviors. Offshore tsunami data take an important role in tsunami forecasting. Tsunamis can be detected at offshore stations earlier than at coastal sites, and the data provide direct information about the impeding tsunamis. When the 2011 Tohoku earthquake occurred, the large tsunamis were clearly observed at various offshore observatories around Japan, such as cabled ocean bottom pressure gauges (OBPGs), GPS buoys and DART. In this study, we retrospectively applied an algorithm of near-field tsunami forecasting (Tsushima et al., 2009, 2012, JGR) to the offshore tsunami data from the 2011 Tohoku earthquake to examine how the algorithm contributes to tsunami forecasting of M9 earthquakes. Our tsunami forecasting algorithm is based on a source estimation. For the algorithm, offshore tsunami waveform data are inverted for spatial distribution of an initial sea-surface displacement, and then coastal tsunami waveforms are synthesized from the estimated source and pre-computed Green's functions by a linear superposition. No assumptions concerning the fault geometry and the size of an earthquake are required in the algorithm. The predictions are repeated by progressively updating the offshore tsunami waveform data. Because individual predictions can be calculated within a few minutes, tsunami predictions can be updated at short intervals of time, thus providing successive tsunami predictions with improved accuracy. We retrospectively applied our algorithm to the tsunami data recorded at 13 offshore stations (6 OBPGs, 6 GPS buoys, and 1 DART) during the 2011 Tohoku tsunami event. As a result of the application made 20 minutes after the earthquake, tsunamis with heights of 5-10 m were forecasted at the coastal sites

  7. Probabilistic estimation of earthquake-induced tsunami occurrences in the Adriatic and northern Ionian seas

    NASA Astrophysics Data System (ADS)

    Armigliato, Alberto; Tinti, Stefano

    2010-05-01

    In the framework of the EU-funded project TRANSFER (Tsunami Risk ANd Strategies For the European Region we faced the problem of assessing quantitatively the tsunami hazard in the Adriatic and north Ionian Seas. Tsunami catalogues indicate that the Ionian Sea coasts has been hit by several large historical tsunamis, some of which of local nature (especially along eastern Sicily, eastern Calabria and the Greek Ionian Islands), while others had trans-basin relevance, like those generated in correspondence with the western Hellenic Trench. In the Adriatic Sea the historical tsunami activity is indeed lower, but not negligible: the most exposed regions on the western side of the basin are Romagna-Marche, Gargano and southern Apulia, while in the eastern side the Dalmatian and Albanian coastlines show the largest tsunami exposure. To quantitatively assess the exposure of the selected coastlines to tsunamis we used a hybrid statistical-deterministic approach, already applied in the recent past to the southern Tyrrhenian and Ionian coasts of Italy. The general idea is to base the tsunami hazard analyses on the computation of the probability of occurrence of tsunamigenic earthquakes, which is appropriate in basins where the number of known historical tsunamis is too scarce to be used in reliable statistical analyses, and the largest part of the tsunamis had tectonic origin. The approach is based on the combination of two steps of different nature. The first step consists in the creation of a single homogeneous earthquake catalogue starting from suitably selected catalogues pertaining to each of the main regions facing the Adriatic and north Ionian basins (Italy, Croatia, Montenegro, Greece). The final catalogue contains 6619 earthquakes with moment magnitude ranging from 4.5 to 8.3 and focal depth lower than 50 km. The limitations in magnitude and depth are based on the assumption that earthquakes of magnitude lower than 4.5 and depth greater than 50 km have no significant

  8. Tsunami Modeling, Forecast and Warning (Invited)

    NASA Astrophysics Data System (ADS)

    Satake, K.

    2010-12-01

    Tsunami is an infrequent natural hazard; however, once it happens, the effects are devastating and can be on global scale, as demonstrated by the 2004 Indian Ocean tsunami. Deterministic modeling of tsunami generation, propagation and coastal behavior has become popular, at least for earthquake tsunamis. Once the earthquake parameters are specified, tsunami arrival times, heights and current velocity at specific coastal points, and inland inundation area can be estimated. Such modeling has been used to make hazard maps usually by assuming largest possible earthquakes. However, smaller tsunamis than such a worst-case scenario occur more frequently. If the hazard maps are used incorrectly, it may lose reliability of coastal residents. Probabilistic tsunami hazard assessments, similar to Probabilistic Seismic Hazard Analysis, have been made for some coasts. The output is tsunami hazard curves, i.e. annual probability (or return period) for specified coastal tsunami heights. A hazard curve is obtained by integration over the aleatory uncertainties, and a large number of hazard curves are made for each branch of logic tress representing epistemic uncertainty. Probabilistic tsunami hazard analysis is used for design of critical facilities but not popularly used for disaster mitigation. Tsunami warning systems, which have been significantly developed since 2004, rely on seismic and sea-level monitoring and pre-made numerical simulation. Real-time data assimilation of offshore sea level measurements can be used to update the warning levels. Tsunami from the February 2010 Chilean earthquake was recorded on many tide gauges and ocean bottom pressure gauges in the Pacific, before it arrived on the Japanese coast about 22 hours after the earthquake. The tsunami height was up to 2 m on the Japanese coast, causing fishery damage amounting 60 million US dollars, but did not cause any human damage.

  9. 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

  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. Tsunami Warning Services for the Caribbean Region

    NASA Astrophysics Data System (ADS)

    Whitmore, P. M.; Ferris, J. C.; Weinstein, S. A.

    2007-05-01

    Tsunami warning and watch services are currently provided to the Caribbean region through a collaborative effort between the two NOAA Tsunami Warning Centers (TWCs): the Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawaii, and the West Coast/Alaska Tsunami Warning Center (WCATWC) in Palmer, Alaska. The WCATWC, in coordination with the Puerto Rico Seismic Network (PRSN), provides fast-response warning services to the U.S. territories of the Commonwealth of Puerto Rico and the U.S. Virgin Islands (PR/VI). The PTWC provides regional watch services to other countries throughout and surrounding the Caribbean Sea as part of the Intergovernmental Coordination Group for the Caribbean Sea and Adjacent Regions. This collaboration is analogous to the TWC's responsibilities in the Pacific basin: the WCATWC provides fast-response warning services for the U.S. west coast states, Alaska, and British Columbia in Canada, while the PTWC provides regional services for countries throughout and surrounding the Pacific Ocean (as well as a fast-response service for the U.S. State of Hawaii). Caribbean seismic data are transmitted to the TWCs through several means. The PRSN directly exports data to the WCATWC, providing the Center sufficient seismic data for the PR/VI region. Additionally, the PRSN provides the TWCs with data gathered from other Caribbean nations. Using modern communication capabilities, the seismic data can be processed at the TWCs at the same time it is processed locally. Another source of high- quality seismic data is the new USGS nine-station array that circles the region. The Global Seismic Network maintains several stations in Caribbean, Central American, and South American nations which are available in real-time to the TWCs. Unfortunately, sea level data coverage is sporadic in the region. The PR/VI has a relatively dense array of coastal tide gages, but coastal tide gage coverage is very sparse for the rest of the Caribbean basin. Three deep-ocean pressure

  12. 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.

  13. The D-linking effect on extraction from islands and non-islands

    PubMed Central

    Goodall, Grant

    2015-01-01

    “D-linked” wh-phrases such as which car are known to increase the acceptability of sentences with island violations. One influential account of this attributes the effect to working memory: the D-linked filler is easier to retrieve at the site of the gap and this leads to the amelioration in acceptability. Such an account predicts that this effect should occur in general with non-trivial wh-dependencies, not just in island environments. An experiment is presented here to test this prediction. Wh-questions with both D-linked and bare wh-phrases and with both island and non-island embedded clauses are presented to participants, who rate their acceptability on a 7-point scale. Results show that D-linking significantly increases acceptability in both island and non-island environments, in accord with analyses that attribute the effect to working memory. In addition, the increase in acceptability is uniform in both types of environments, suggesting that the island effect itself may not be attributable to working memory. PMID:25601844

  14. 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.

  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. 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.

    2016-05-01

    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

  17. 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.

  18. 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.

  19. 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

  20. 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

  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. 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.

  3. 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

  4. Tsunami Amplification due to Focusing

    NASA Astrophysics Data System (ADS)

    Moore, C. W.; Kanoglu, U.; Titov, V. V.; Aydin, B.; Spillane, M. C.; Synolakis, C. E.

    2012-12-01

    Tsunami runup measurements over the periphery of the Pacific Ocean after the devastating Great Japan tsunami of 11 March 2011 showed considerable variation in far-field and near-field impact. This variation of tsunami impact have been attributed to either directivity of the source or by local topographic effects. Directivity arguments alone, however, cannot explain the complexity of the radiated patterns in oceans with trenches and seamounts. Berry (2007, Proc. R. Soc. Lond. A 463, 3055-3071) discovered how such underwater features may concentrate tsunamis into cusped caustics and thus cause large local amplifications at specific focal points. Here, we examine focusing and local amplification, not by considering the effects of underwater diffractive lenses, but by considering the details of the dipole nature of the initial profile, and propose that certain regions of coastline are more at-risk, not simply because of directivity but because typical tsunami deformations create focal regions where abnormal tsunami wave height can be registered (Marchuk and Titov, 1989, Proc. IUGG/IOC International Tsunami Symposium, Novosibirsk, USSR). In this work, we present a new general analytical solution of the linear shallow-water wave equation for the propagation of a finite-crest-length source over a constant depth without any restriction on the initial profile. Unlike the analytical solution of Carrier and Yeh (2005, Comp. Mod. Eng. & Sci. 10(2), 113-121) which was restricted to initial conditions with Gaussian profiles and involved approximation, our solution is not only exact, but also general and allows the use of realistic initial waveform such as N-waves as defined by Tadepalli and Synolakis (1994, Proc. R. Soc. Lond. A 445, 99-112). We then verify our analytical solution for several typical wave profiles, both with the NOAA tsunami forecast model MOST (Titov and Synolakis, 1998, J. Waterw. Port Coast. Ocean Eng. 124(4), 157-171) which is validated and verified through

  5. 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.

  6. Peru 2007 tsunami runup observations and modeling

    NASA Astrophysics Data System (ADS)

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

    2008-05-01

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

  7. An accessibility graph-based model to optimize tsunami evacuation sites and routes in Martinique, France

    NASA Astrophysics Data System (ADS)

    Péroche, M.; Leone, F.; Gutton, R.

    2014-01-01

    The risk of tsunami threatens the whole Caribbean coastline especially the Lesser Antilles. The first available models of tsunami propagation estimate that the travel time from the closest seismic sources would only take few minutes to impact the Martinique Island. Considering this threat, the most effective measure is a planned and organized evacuation of the coastal population. This requires an efficient regional warning system, estimation of the maximum expected tsunami flood height, preparation of the population to evacuate, and drawing up of local and regional emergency plans. In order to produce an efficient evacuation plan, we have to assess the number of people at risk, the potential evacuation routes, the safe areas and the available time to evacuate. However, this essential information is still lacking in the French West Indies emergency plans. This paper proposes a model of tsunami evacuation sites accessibility for Martinique directly addressed to decision makers. It is based on a population database at a local scale, the development of connected graphs of roads, the identification of potential safe areas and the velocity setting for pedestrians. Evacuation routes are calculated using the Dijkstra's algorithm which gives the shortest path between areas at risk and designated evacuation sites. The first results allow us to map the theoretical times and routes to keep the exposed population safe and to compare these results with a tsunami travel time scenario.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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…

  14. 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)

  15. Vulnerability assessment and protective effects of coastal vegetation during the 2004 Tsunami in Sri Lanka

    NASA Astrophysics Data System (ADS)

    Kaplan, M.; Renaud, F. G.; Lüchters, G.

    2009-08-01

    The tsunami of December 2004 caused extensive human and economic losses along many parts of the Sri Lankan coastline. Thanks to extensive national and international solidarity and support in the aftermath of the event, most people managed to restore their livelihoods completely but some households did not manage to recover completely from the impacts of the event. The differential in recovery highlighted the various vulnerabilities and coping capacities of communities exposed to the tsunami. Understanding the elements causing different vulnerabilities is crucial to reducing the impact of future events, yet capturing them comprehensively at the local level is a complex task. This research was conducted in a tsunami-affected area in southwestern Sri Lanka to evaluate firstly the role of coastal vegetation in buffering communities against the tsunami and secondly to capture the elements of vulnerability of affected communities. The area was chosen because of its complex landscape, including the presence of an inlet connecting the Maduganga estuary with the sea, and because of the presence of remaining patches of coastal vegetation. The vulnerability assessment was based on a comprehensive vulnerability framework and on the Sustainable Livelihoods Framework in order to detect inherent vulnerabilities of different livelihood groups. Our study resulted in the identification of fishery and labour-led households as the most vulnerable groups. Unsurprisingly, analyses showed that damages to houses and assets decreased quickly with increasing distance from the sea. It could also be shown that the Maduganga inlet channelled the energy of the waves, so that severe damages were observed at relatively large distances from the sea. Some reports after the tsunami stated that mangroves and other coastal vegetation protected the people living behind them. Detailed mapping of the coastal vegetation in the study area and subsequent linear regression revealed significant differences

  16. Tsunami Generation Above a Sill

    NASA Astrophysics Data System (ADS)

    Stefanakis, Themistoklis S.; Dias, Frédéric; Synolakis, Costas

    2015-03-01

    The generation of surface waves by seafloor displacement is a classic problem that arises in the study of tsunamis. The generation of waves in a two-dimensional domain of uniform depth by uplift or subsidence of a portion of a flat bottom boundary has been elegantly studied by Hammack (Tsunamis: a model of their generation and propagation, Ph.D. thesis, California Institute of Technology, 1972), for idealized motions. The physical problem of tsunami generation is more complex; even when the final displacement is known from seismic analysis, the deforming seafloor includes relief features such as mounts and trenches. Here, following Kajiura (J Oceanogr Soc Jpn 28:260-277, 1972), we investigate analytically the effect of bathymetry on the surface wave generation, by solving the forced linear shallow water equation. While Kajiura's geometry consisted of a step-type bottom bathymetry with a rectangular uplift to understand the effect of the continental shelf on tsunami generation, our model bathymetry consists of an uplifting cylindrical sill initially resting on a flat bottom, a geometry which helps evaluate the effect of seamounts on tsunami generation. We find that as the sill height increases, partial wave trapping reduces the wave height in the far field, while amplifying it above the sill.

  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. Estimating the Likelihood of Extreme Seismogenic Tsunamis

    NASA Astrophysics Data System (ADS)

    Geist, E. L.

    2011-12-01

    Because of high levels of destruction to coastal communities and critical facilities from recent tsunamis, estimating the likelihood of extreme seismogenic tsunamis has gained increased attention. Seismogenic tsunami generating capacity is directly related to the scalar seismic moment of the earthquake. As such, earthquake size distributions and recurrence can inform the likelihood of tsunami occurrence. The probability of extreme tsunamis is dependent on how the right-hand tail of the earthquake size distribution is specified. As evidenced by the 2004 Sumatra-Andaman and 2011 Tohoku earthquakes, it is likely that there is insufficient historical information to estimate the maximum earthquake magnitude (Mmax) for any specific subduction zone. Mmax may in fact not be a useful concept for subduction zones of significant length. Earthquake size distributions with a soft corner moment appear more consistent with global observations. Estimating the likelihood of extreme local tsunami runup is complicated by the fact that there is significant uncertainty in the scaling relationship between seismic moment and maximum local tsunami runup. This uncertainty arises from variations in source parameters specific to tsunami generation and the near-shore hydrodynamic response. The primary source effect is how slip is distributed along the fault relative to the overlying water depth. For high slip beneath deep water, shoaling amplification of the tsunami increases substantially according to Green's Law, compared to an equivalent amount of slip beneath shallow water. Both stochastic slip models and dynamic rupture models of tsunamigenic earthquakes are explored in a probabilistic context. The nearshore hydrodynamic response includes attenuating mechanisms, such as wave breaking, and amplifying mechanisms, such as constructive interference of trapped and non-trapped modes. Probabilistic estimates of extreme tsunamis are therefore site specific, as indicated by significant variations

  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. 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.

  2. Improving tsunami warning using commercial ships

    NASA Astrophysics Data System (ADS)

    Foster, James H.; Brooks, Benjamin A.; Wang, Dailin; Carter, Glenn S.; Merrifield, Mark A.

    2012-05-01

    Accurate and rapid detection and assessment of tsunamis is critical for effective mitigation. We show here that a modest ˜10 cm tsunami from the M8.8 27 Feb 2010 Maule, Chile earthquake was detected by kinematic Global Positions System (GPS) solutions from a ship underway in the open ocean - the first time shipboard tsunami detection has been achieved. Our results illustrate how the commercial shipping fleet represents a vast infrastructure of potential open ocean GPS platforms on shipping lanes that provide extremely good spatial coverage around most tsunamigenic source regions. Given the affordability of geodetic GPS systems, and ever-improving satellite communications, it would be possible to equip a significant portion of the shipping fleet with real-time-streamed GPS systems and create a cost-effective tsunami monitoring network with denser and more distributed coverage. We project that such a system would have detected the 2004 Indian Ocean tsunami in less than an hour.

  3. Tsunamis: Sanitation and Hygiene

    MedlinePlus

    ... Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Tsunamis: Sanitation and Hygiene Language: English Español (Spanish) Recommend on ... your family by following these steps Hygiene and Sanitation From the CDC Water-Related Emergencies and Outbreaks ...

  4. Tsunami early warning and decision support

    NASA Astrophysics Data System (ADS)

    Steinmetz, T.; Raape, U.; Teßmann, S.; Strobl, C.; Friedemann, M.; Kukofka, T.; Riedlinger, T.; Mikusch, E.; Dech, S.

    2010-09-01

    An innovative newly developed modular and standards based Decision Support System (DSS) is presented which forms part of the German Indonesian Tsunami Early Warning System (GITEWS). The GITEWS project stems from the effort to implement an effective and efficient Tsunami Early Warning and Mitigation System for the coast of Indonesia facing the Sunda Arc along the islands of Sumatra, Java and Bali. The geological setting along an active continental margin which is very close to densely populated areas is a particularly difficult one to cope with, because potential tsunamis' travel times are thus inherently short. National policies require an initial warning to be issued within the first five minutes after an earthquake has occurred. There is an urgent requirement for an end-to-end solution where the decision support takes the entire warning chain into account. The system of choice is based on pre-computed scenario simulations and rule-based decision support which is delivered to the decision maker through a sophisticated graphical user interface (GUI) using information fusion and fast information aggregation to create situational awareness in the shortest time possible. The system also contains risk and vulnerability information which was designed with the far end of the warning chain in mind - it enables the decision maker to base his acceptance (or refusal) of the supported decision also on regionally differentiated risk and vulnerability information (see Strunz et al., 2010). While the system strives to provide a warning as quickly as possible, it is not in its proper responsibility to send and disseminate the warning to the recipients. The DSS only broadcasts its messages to a dissemination system (and possibly any other dissemination system) which is operated under the responsibility of BMKG - the meteorological, climatological and geophysical service of Indonesia - which also hosts the tsunami early warning center. The system is to be seen as one step towards

  5. 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.

  6. 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.

  7. Landslides and tsunamis

    USGS Publications Warehouse

    Keating, Barbara H., (Edited By); Waythomas, Christopher F.; Dawson, Alastair G.

    2000-01-01

    The study of tsunamis has been shifting away from theoretical modeling of tsunami source, wave propagation and runup toward multidisciplinary investigations, with an emphasis on field studies. This collection of papers highlights the many approaches being utilized to study landslides and tsunamis.

  8. 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. ... Tsunami: Sri Lanka location:  Asia Indian Ocean thumbnail:  ...

  9. 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. PMID:26062739

  10. 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

  11. Tsunami response system for ports in Korea

    NASA Astrophysics Data System (ADS)

    Cho, H.-R.; Cho, J.-S.; Cho, Y.-S.

    2015-03-01

    The tsunamis that have occurred in many places around the world over the past decade have taken a heavy toll on human lives and property. The eastern coast of the Korean Peninsula is not safe from tsunamis, particularly the eastern coastal areas, which have long sustained tsunami damage. The aim of this study was to mitigate the casualties and property damage on the east eastern coast by developing a proper tsunami response system for important ports and harbors with high population densities and high concentrations of key national industries. For study purposes, the government-managed major international trade ports and coastal harbors were selected and an effective tsunami response system was formulated based on field surveys and related literature.

  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. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. Real-time Tsunami Warning Operations at the NOAA West Coast/Alaska Tsunami Warning Center

    NASA Astrophysics Data System (ADS)

    Whitmore, P.; Huang, P.; Crowley, H.; Ferris, J.; Hale, D.; Knight, W.; Medbery, A.; Nyland, D.; Preller, C.; Turner, B.; Urban, G.

    2007-12-01

    The West Coast/Alaska Tsunami Warning Center (WCATWC) in Palmer, Alaska and the Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawaii, provide tsunami warning services for a large portion of the world's coasts. The WCATWC has primary responsibility for providing tsunami detection, warnings, and forecasts to Canada, Puerto Rico, Virgin Islands, and all U.S. States except Hawaii. WCATWC also acts as back-up for the PTWC, requiring the center to constantly monitor global tsunami activities by rapidly detecting and evaluating earthquakes for their tsunamigenic potential. The Centers' goals are to issue initial messages as quickly as possible to alert those near the source to potential danger (assuming there is any), and to follow that with a reasonable forecast of impact level. With these goals in mind, a Watchstander's initial action is based entirely on estimates of tsunami potential from the earthquake's source parameters. The course of action for the first message is determined primarily by the earthquake's magnitude, location, tsunami history, tsunami travel time, estimated threat based on pre-computed models, and pre-set criteria. Supplemental messages, if necessary, are based on wave observations and forecasts generated from hydrodynamic models (which are calibrated with near real-time observations). In April 2006, the WCATWC increased staff level so that the Center can be staffed 24/7 with two watchstanders. Since then, the Center's response time for events within the primary area-of-responsibility has decreased to less than 5 minutes. In order to illustrate the WCATWC's real time tsunami warning operational environment, tsunami warning operation timelines for several tsunamigenic earthquakes - including the September 12 southern Sumatra 8.4 and the January 13 Kuril Island 8.1 earthquakes - are provided. The timelines highlight the key parameters and observations that guide tsunami warning operations chronicling the event through: 1) initial alarm, 2

  19. Great East Japan Earthquake Tsunami

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    The 11 March 2011, Mw 9.0 Great East Japan Earthquake, already among the most destructive earthquakes in modern history, emanated from a fault rupture that extended an estimated 500 km along the Pacific coast of Honshu. This earthquake is the fourth among five of the strongest temblors since AD 1900 and the largest in Japan since modern instrumental recordings began 130 years ago. The earthquake triggered a huge tsunami, which invaded the seaside areas of the Pacific coast of East Japan, causing devastating damages on the coast. Artificial structures were destroyed and planted forests were thoroughly eroded. Inrush of turbulent flows washed backshore areas and dunes. Coastal materials including beach sand were transported onto inland areas by going-up currents. Just after the occurrence of the tsunami, we started field investigation of measuring thickness and distribution of sediment layers by the tsunami and the inundation depth of water in Sendai plain. Ripple marks showing direction of sediment transport were the important object of observation. We used a soil auger for collecting sediments in the field, and sediment samples were submitted for analyzing grain size and interstitial water chemistry. Satellite images and aerial photographs are very useful for estimating the hydrogeological effects of tsunami inundation. We checked the correspondence of micro-topography, vegetation and sediment covering between before and after the tsunami. The most conspicuous phenomenon is the damage of pine forests planted in the purpose of preventing sand shifting. About ninety-five percent of vegetation coverage was lost during the period of rapid currents changed from first wave. The landward slopes of seawalls were mostly damaged and destroyed. Some aerial photographs leave detailed records of wave destruction just behind seawalls, which shows the occurrence of supercritical flows. The large-scale erosion of backshore behind seawalls is interpreted to have been caused by

  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. Modeling potential tsunami river surge in Redwood Creek, California

    NASA Astrophysics Data System (ADS)

    Courtney, J. E.; Admire, A. R.; Nicolini, T.; Dengler, L. A.

    2013-12-01

    Significant destruction can be caused by tsunami penetration in estuaries and up river channels. In the 1964 tsunami on the west coast of North America, much of the resulting damage was caused by tsunami river bores penetrating miles inland. A HEC-RAS model is used in this study to look at the likely extent of inundation from both distant and near-field tsunamis in Redwood Creek on the north coast of California. The Redwood Creek drainage basin has been analyzed extensively for riverine flooding, levee stability and sediment transport. The unsteady flow model in HEC-RAS uses an implicit finite difference scheme to approximate solutions to the continuity and momentum equations. Two different scenarios are evaluated in this analysis: 1. tsunami propagation up a dry river channel; 2. tsunami propagation up a partially full river channel. Scenario 1 provides the baseline for propagation behavior without river flow influence. Scenario 2 uses the HEC-RAS model to determine steady state conditions in the channel for different flow rates to establish initial boundary conditions. The tsunami magnitude and flow conditions are altered to determine the effect on tsunami surge propagation. This is achieved by altering the downstream boundary conditions to simulate the influence of a tsunami surge propagation event. A sensitivity analysis is conducted on the model parameters. The study will assist in tsunami hazard modeling and mitigation in areas where tsunami surge propagation is a concern to communities located along rivers.

  3. A Guidebook to Help Coastal Sumatran Communities Prepare for Tsunamis

    NASA Astrophysics Data System (ADS)

    Samant, L.; Tobin, L. T.; Tucker, B. E.

    2007-12-01

    One way to save lives in future tsunamis in coastal Sumatran communities - where more than one million people live and where tsunamis can strike less than one half hour after the triggering earthquake - is to help these communities prepare themselves. To this end, GeoHazards International (GHI) has developed, with a team of advisors from the fields of earth science, civil engineering, emergency response management and social science, a tsunami preparedness guidebook that summarizes state-of-the-art research and worldwide experience in community tsunami preparedness. This guidebook (available at no cost on www.geohaz.org) introduces essential information about tsunamis, tsunami risk mapping, evacuation planning, community education, tsunami warning systems, and the reduction of damage that tsunamis can cause. It describes how to plan and conduct effective tsunami safety programs. Particular emphasis is placed on methods to evacuate quickly and safely all areas that could be flooded. Each section of the guidebook points to sources that provide supplementary, detailed information that may be important to particular communities. The guidebook is aimed at any person - a concerned citizen, government official, business leader, or member of a community organization - who is willing to become an advocate for local tsunami safety. Scientific expertise is not needed. GHI now seeks assistance in distributing this guidebook and in working with grassroots and international organizations to help Sumatran coastal communities use it to prepare for the next tsunami.

  4. 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

  5. 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

  6. 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.

  7. 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

  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. 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

  10. Island-corner barrier effect in two-dimensional pattern formation at surfaces

    SciTech Connect

    Zhong, Jianxin; Zhang, Tianjiao; Zhang, Zhenyu; Lagally, Max G.

    2001-03-15

    Using rate-equation analysis, kinetic Monte Carlo simulations, and embedded-atom model calculations, we establish the crucial importance of island-corner crossing in determining the island morphology during submonolayer epitaxy. We show that compact islands can be formed only if adatoms can frequently cross island corners; conversely, without effective corner crossing the islands must be noncompact with fractional dimensionality. These conclusions provide the basis for understanding initial island morphologies in existing experiments.

  11. 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.

  12. 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.

  13. 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.

  14. Analyses of Tsunami Events using Simple Propagation Models

    NASA Astrophysics Data System (ADS)

    Chilvery, Ashwith Kumar; Tan, Arjun; Aggarwal, Mohan

    2012-03-01

    Tsunamis exhibit the characteristics of ``canal waves'' or ``gravity waves'' which belong to the class of ``long ocean waves on shallow water.'' The memorable tsunami events including the 2004 Indian Ocean tsunami and the 2011 Pacific Ocean tsunami off the coast of Japan are analyzed by constructing simple tsunami propagation models including the following: (1) One-dimensional propagation model; (2) Two-dimensional propagation model on flat surface; (3) Two-dimensional propagation model on spherical surface; and (4) A finite line-source model on two-dimensional surface. It is shown that Model 1 explains the basic features of the tsunami including the propagation speed, depth of the ocean, dispersion-less propagation and bending of tsunamis around obstacles. Models 2 and 3 explain the observed amplitude variations for long-distance tsunami propagation across the Pacific Ocean, including the effect of the equatorial ocean current on the arrival times. Model 3 further explains the enhancement effect on the amplitude due to the curvature of the Earth past the equatorial distance. Finally, Model 4 explains the devastating effect of superposition of tsunamis from two subduction event, which struck the Phuket region during the 2004 Indian Ocean tsunami.

  15. The 11 March 2011 Tohoku tsunami wavefront mapping across offshore Southern California

    NASA Astrophysics Data System (ADS)

    Lin, Fan-Chi; Kohler, Monica D.; Lynett, Patrick; Ayca, Aykut; Weeraratne, Dayanthie S.

    2015-05-01

    The 11 March 2011 (Mw = 9.0) Tohoku tsunami was recorded by a temporary array of seafloor pressure gauges deployed off the coast of Southern California, demonstrating how dense array data can illustrate and empirically validate predictions of linear tsunami wave propagation characteristics. A noise cross-correlation method was used to first correct for the pressure gauge instrument phase response. Phase and group travel times were then measured for the first arrival in the pressure gauge tsunami waveforms filtered in narrow bands around 30 periods between 200 and 3000 s. For each period, phase velocities were estimated across the pressure gauge array based on the phase travel time gradient using eikonal tomography. Clear correlation was observed between the phase velocity and long-wavelength bathymetry variations where fast and slow velocities occurred for deep and shallow water regions, respectively. In particular, velocity gradients are pronounced at the Patton Escarpment and near island plateaus due to the abrupt bathymetry change. In the deep open ocean area, clear phase velocity dispersion is observed. Comparison with numerically calculated tsunami waveforms validates the approach and provides an independent measure of the finite-frequency effect on phase velocities at long periods.

  16. Modeling Tsunamis from Potential Submarine Landslides in the Puerto Rico Region

    NASA Astrophysics Data System (ADS)

    Lopez, A. M.; Horrillo, J.; Huerfano Moreno, V. A.; Mercado, A.

    2012-12-01

    Evidence of submarine landslides found on high-resolution bathymetry around the Puerto Rico - Virgin Islands region indicate that tsunamis may have formed in the past, thus affecting coastal zones around Puerto Rico. Furthermore, it suggests that future submarine landslides in the vicinity are likely to occur in the future, resulting in destruction and devastation never seen before for coastal communities in Puerto Rico. With the presence of massive amphitheaters offshore along the northern Puerto Rico coast, and the most recent evidence of the October 11, 1918 tsunami along its northwestern coast, the threat to coastal communities is higher than previously thought. Submarine landslides progress through time as slopes reach their stability. With numerous processes leading to instabilities and subsequent failure, the possibility of experiencing new submarine landslides is real and thus require an assessment as to quantify potential sources, their dimensions, volumes, resulting tsunamis, and their effects onshore. As part of a project to produce evacuation maps from potential sources, the National Tsunami Hazards Mitigation Program funded the Puerto Rico Seismic Network to identify sources, run tsunami simulations and estimate inundation and run-up values. In addition to 15 past submarine landslides observed in the region's bathymetry, 5 scenarios of submarine landslides have been identified as potentially occurring in the future. Whether any or all of these potential case scenarios occur in the upcoming century is unknown, however, results from this study are critical to quantify their effects along coastal areas and therefore prepare communities for their occurrence. Three such cases lie along the northern offshore region, where the Arecibo and Loiza amphitheaters are found, an area where the geology favors such phenomenons. In contrast, the southern offshore region do not show a similar trend and thus seem unlikely to produce large events. We have used available

  17. 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

    2016-06-01

    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.

  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. The Great 1787 Mexican Tsunami

    NASA Astrophysics Data System (ADS)

    Nunez-Cornu, F. J.; Ortiz, M.; Sanchez, J. J.; Suarez-Plascencia, C.

    2008-12-01

    Tsunamis have proven to represent a significant hazard around the globe and there is increased awareness about their occurrence. The Pacific coast in southern México is no exception, because there is firm evidence of the effects of past large tsunamis. Here we present results from computer-aided modeling of the March 28, 1787 - 'San Sixto' earthquake and tsunami, and focus on the regions of Acapulco, Corralero, Jamiltepec, and Tehuantepec, located along the Guerrero- Oaxaca coast. The theoretical waveforms suggest wave heights in excess of 4 m, and 18 m at specific locations in Acapulco and Corralero, respectively, and wave heights of at least 2 m at locations in Jamiltepec and Tehuantepec. From our modelling results and based on historical documents and the topography of the area, we conclude that these wave heights would have been sufficient to cause inundations that in the case of Acapulco were restricted to several meters inland, but in other areas like Corralero reached at least 6 km inland. Our results are consistent with published and unpublished damage reports that attest to the hazards associated with great earthquakes and tsunamis along the subduction zone in Mexico.

  20. 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

  1. 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

  2. Satellite Observations Defying the Long-Held Tsunami Genesis Theory

    NASA Astrophysics Data System (ADS)

    Song, Y.; Han, S.

    2009-12-01

    Using seismographs and GPS displacement measurements, we have fully estimated the seafloor deformation history of the December 2004 Sumatra-Andaman earthquake and the March 2005 Nias Island earthquake by separating their deformation period into intervals of 800-sec, 1-hour, and 6-months. Their corresponding gravity changes (induced by the seafloor deformation) are 11.3, 12.5, and 14.9 microgalileo, respectively, consistent with the Gravity Recovery and Climate Experiment (GRACE) satellites measurements of 15 microgalileo for the same period of six months. However, the vertical component of the accumulated seafloor deformation during the tsunami formation period could only generate a potential energy of 1.2E+15 Joules and account for only one third of the actual tsunami height measured by altimeters. The evidence is overwhelmingly contrary to the long-held theory that the vertical deformation of seafloor is the primary source of tsunamis. Surprisingly, we also found that a pioneering wave-maker experiment, which conceived the vertically-forced tsunami genesis theory in 1980s, used an exaggerated experimental ratio of the horizontal slip distance to the water depth, the key non-dimensional parameter that allows comparing the experiment with reality on an apple-to-apple basis, about 200 times of realistic earthquake parameters. The experiment is problematic in conceiving the vertically-forced tsunami theory. We conclude that the tsunami source has been poorly understood and the tsunami formation mechanism is not as simple as previously thought. Our study suggests a new method of using gravity measurement from space to constrain the under-sea earthquake source for tsunami modeling and to gain insight into the tsunami genesis theory. Seafloor deformation, corresponding gravity changes, and GRACE measurements of the December 26 Sumatra-Andaman earthquake and the March 2005 Nias Island earthquake.

  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. 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.

  5. 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.

  6. 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

  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. Real-time forecasting of near-field tsunamis based on source estimation from offshore tsunami data (Invited)

    NASA Astrophysics Data System (ADS)

    Tsushima, H.; Hayashi, Y.; Maeda, K.; Yokota, T.

    2013-12-01

    Near-field tsunamis in areas close to subduction zones can reach the coast in a few tens of minutes or less, and cause loss of life as well as severe damage to houses and infrastructures in coastal communities. Real-time tsunami forecasting is one of the effective ways to mitigate tsunami disasters. Transmission of a tsunami warning based on rapid and accurate tsunami forecasting to coastal communities helps the residents to make the decisions about their evacuation behaviors. Offshore tsunami data take an important role in tsunami forecasting. Tsunamis can be detected at offshore stations earlier than at coastal sites, and the data provide direct information about the impending tsunamis. In this paper, we present a method to forecast near-field tsunamis from offshore tsunami data using inversion and tsunami amplification factor techniques. We also introduce a prototype of tsunami forecasting system in which our forecasting method is installed. Our tsunami forecasting algorithm is based on a source estimation. For the algorithm, offshore tsunami waveform data are inverted for spatial distribution of an initial sea-surface displacement, and then tsunami waveforms are synthesized from the estimated source and pre-computed Green's functions by a linear superposition to forecast tsunamis at an offshore point near a coastal site. The predicted tsunami heights at the offshore points are amplified to obtain those at coastal sites using the amplification factors derived from actual tsunami observations empirically. No assumptions concerning the fault geometry and the size of an earthquake are required in the algorithm. An empirical amplification factor includes the effect of actual topography on tsunami heights that should be difficult to be modeled by the linear combination of the Green's functions. The predictions are repeated by progressively updating the offshore tsunami waveform data. Because individual predictions can be calculated within a few minutes, tsunami

  9. 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.

  10. Assessing historical rate changes in global tsunami occurrence

    NASA Astrophysics Data System (ADS)

    Geist, Eric L.; Parsons, Tom

    2011-10-01

    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 >1 m. The record of these tsunamis appears to be complete since approximately 1890. A secondary data set of tsunamis >0.1 m 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 >1 m data set, but the Poisson null hypothesis cannot be falsified for the shorter duration >0.1 m 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.

  11. 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

  12. 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.

  13. 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

  14. 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

  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. 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

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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. PMID:27508461

  3. The 1998 PNG tsunami: multidisciplinary evidence on its architecture and run-up effects - pathways to prediction?

    NASA Astrophysics Data System (ADS)

    Tappin, D. R.; Watts, P.; Grilli, S. T.; Matsumoto, T.

    2002-12-01

    To address the threat of tsunami prediction from local slumps is problematic. To generate realistic models of tsunami generation and runup, an essential requirement is for the models to be validated by direct evidence provided from offshore surveying. Case studies are therefore required and a seminal example is the Papua New Guinea tsunami of 1998. After considerable controversy over the origin of the 1998 PNG tsunami, there is now a body of evidence that supports a cause by sediment slumping offshore of the devastated area. In association with onshore run-up measurements, five surveys carried out between 1999 and 2000 offshore of the most affected area have resulted in a composite suite of data that locates and images the slump and also allows appraisal of its geotechnical properties. An original dataset of multibeam bathymetry, high resolution 3.5kHz data, multichannel seismic, and piston cores in association with ROV and submersible images and direct seabed observation has now been improved with the acquisition in 2001 of a closely spaced grid of single channel seismic data. Better definition of the slump is now possible for use in modelling. The slump geometry in the context of the regional tectonic setting, suggests a novel type of stability analysis performed with a 1D-consolidation code. The simulation results help constrain slump motion following failure. The geologic, bathymetric and soil mechanic data are now all used in new simulations of fully 3D tsunami generation by the slump as newly defined. The result is a more definite assessment of the susceptibility to slumping of the area offshore of northern PNG. The interpretations and analyses employed in this work may contribute to the identification of other regions susceptible to comparable offshore slumping and tsunami generation.

  4. The 1998 PNG tsunami: multidisciplinary evidence on its architecture and run-up effects - pathways to prediction?

    NASA Astrophysics Data System (ADS)

    Tappin, D.; Watts, P.; Grilli, S.; Biscontin, G.; Pestana, J.; Matsumoto, T.

    2003-04-01

    To address the threat of tsunami prediction from local slumps is problematic. To generate realistic models of tsunami generation and runup an essential requirement is for the models to be validated by direct evidence provided from offshore surveying. Case studies are therefore required and a seminal example is the Papua New Guinea tsunami of 1998. After considerable controversy over the origin of the 1998 PNG tsunami, there is now a body of evidence that supports a cause by sediment slumping offshore of the devastated area. In association with onshore run-up measurements, four surveys carried out between 1999 and 2001 offshore of the most affected area have resulted in a composite suite of data that locates and images the slump and also allows appraisal of its geotechnical properties. An original dataset of multibeam bathymetry, high resolution 3.5kHz data, multichannel seismic, and piston cores in association with ROV and submersible images and direct seabed observation has now been improved with the acquisition in 2001 of a closely spaced set of single channel seismic data. Better definition of the slump is now possible for use in modelling. The regional tectonic setting, combined with the slump geometry, suggests a novel type of stability analysis performed with a 1D-consolidation code. The simulation results help constrain slump motion following failure. The geologic, bathymetric and soil mechanic data are now all used in new simulations of fully 3D tsunami generation by the slump as newly defined. The result is a more definite assessment of the susceptibility to slumping of the area offshore of northern PNG. The interpretations and analyses employed in this work may contribute to the identification of other regions susceptible to comparable offshore slumping and tsunami generation.

  5. 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

  6. 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

  7. 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

  8. 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

  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

    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.

  11. TI: The West Coast and Alaska Tsunami Warning Center Forecast Model Project Applied to an Operational Tsunami Threat-database

    NASA Astrophysics Data System (ADS)

    Knight, W.; Huang, P.; Whitmore, P.; Sterling, K.

    2008-12-01

    Continuous improvement in the NOAA/West Coast & Alaska Tsunami Warning Center (WCATWC) forecast model has allowed the consideration of new uses for this model. These improvements include a finer propagation mesh, more model sources and magnitudes, runup boundary conditions, and continuous, unbroken fine coastal meshes. The focus of this report is on a new operational use of the model at the WCATWC - creation of a threat database of tsunami impacts on US and Canadian coastlines. Since all forecast model data is pre-computed, this concept should be easily realized. One recent case which showed the utility of a model-based threat database was the 4-1-2007 Solomon Islands Tsunami event. Tsunami energy maps clearly showed the energy was directed southwest and was no danger to regions to the northeast. Another case was the use of modeled tsunamis and their synthetic mareograms in the design of Gulf and Atlantic coast tsunami warning criteria. Currently, the only quantitative model data to appear in tsunami messages are ETAs for the leading edge of the tsunami wave train (the expected impact level is described in text - based on forecast model data). Since runups can now be forecasted for any coastal point, they can be used to constrain initial warning/watch/advisory messages to only threatened regions and can be saved to a database for later inclusion (along with ETAs) in tsunami bulletins. Present practice is to include all areas within a certain travel time or distance from epicenter in the initial warning bulletin, regardless of the threat. Since watch-warning- advisory breakpoints are based in the later bulletins on forecasted wave heights, the database can also be used to refine the extent of the warned zones. With full modeled mareograms similarly saved to a database, additional wave information like initial recession / elevation, or ETAs for first and highest waves can be added to tsunami bulletins. By comparison of scaled model prediction to historic tide gauge

  12. 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

  13. Numerical modelling of tsunami generated by the 1650 eruption of Kolumbo, South Aegean Sea, Greece

    NASA Astrophysics Data System (ADS)

    Ulvrova, M.; Paris, R.; Kelfoun, K.; Nomikou, P.

    2013-12-01

    Historical 1650 tsunami generated by explosion of Kolumbo volcano was investigated. Using nonlinear shallow water equations implemented in COMCOT tsunami modelling package we simulate for the tsunami generation and propagation, and compute the inundation distances inland along the nearby Santorini island. Two tsunamigenic mechanisms are tested. First, we assume a scenario of phreatomagmatic explosion. Eruption is investigated using a model for shallow underwater explosions. A systematic study is performed for explosion energy range between 1014 and 1017~J. Second, we employed a caldera collapse scenario with duration up to 2~h. The first waves hit the coast of Santorini, the most populated island in the area and also the closest one to Kolumbo ( ˜~7~km), in about 3~min. Calculated inundation distances with predicted nearshore waves amplitudes provide insights into possible tsunami impact and help to assess the tsunami hazard for this region.

  14. 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.; Lukijanto; 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.

  15. 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.

  16. 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.

  17. The 2010 Mw 7.8 Mentawai earthquake: Very shallow source of a rare tsunami earthquake determined from tsunami field survey and near-field GPS data

    NASA Astrophysics Data System (ADS)

    Hill, Emma M.; Borrero, Jose C.; Huang, Zhenhua; Qiu, Qiang; Banerjee, Paramesh; Natawidjaja, Danny H.; Elosegui, Pedro; Fritz, Hermann M.; Suwargadi, Bambang W.; Pranantyo, Ignatius Ryan; Li, Linlin; MacPherson, Kenneth A.; Skanavis, Vassilis; Synolakis, Costas E.; Sieh, Kerry

    2012-06-01

    The Mw 7.8 October 2010 Mentawai, Indonesia, earthquake was a "tsunami earthquake," a rare type of earthquake that generates a tsunami much larger than expected based on the seismic magnitude. It produced a locally devastating tsunami, with runup commonly in excess of 6 m. We examine this event using a combination of high-rate GPS data, from instruments located on the nearby islands, and a tsunami field survey. The GPS displacement time series are deficient in high-frequency energy, and show small coseismic displacements (<22 cm horizontal and <4 cm subsidence). The field survey shows that maximum tsunami runup was >16 m. Our modeling results show that the combination of the small GPS displacements and large tsunami can only be explained by high fault slip at very shallow depths, far from the islands and close to the oceanic trench. Inelastic uplift of trench sediments likely contributed to the size of the tsunami. Recent results for the 2011 Mw 9.0 Tohoko-Oki earthquake have also shown shallow fault slip, but the results from our study, which involves a smaller earthquake, provide much stronger constraints on how shallow the rupture can be, with the majority of slip for the Mentawai earthquake occurring at depths of <6 km. This result challenges the conventional wisdom that the shallow tips of subduction megathrusts are aseismic, and therefore raises important questions both about the mechanical properties of the shallow fault zone and the potential seismic and tsunami hazard of this shallow region.

  18. 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.

  19. 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)"

  20. Studies provide new insights into Japan's March 2011 tsunami

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2011-12-01

    New data, field studies, modeling efforts, and surveys are revealing a wealth of information about the devastating tsunami that followed the 11 March 2011 Tohoku earthquake. The earthquake and resulting tsunami caused massive destruction and the loss of about 20,000 lives. At the AGU Fall Meeting last week in San Francisco, Calif., scientists reported a variety of new insights about the tsunami and its effects and about tsunami defense mechanisms, ways to forecast tsunami inundation, and public perception of risk. For example, part of the reason the tsunami generated by the Tohoku quake was so large and destructive was that it was a "merging tsunami." Merging tsunamis, which have been hypothesized but not previously observed with certainty, grow in size dramatically when seafloor topography alters the direction in which the waves are traveling and causes two waves to merge into a larger wave. The alteration of wave paths by complex ocean-floor topography makes it difficult to predict where the largest waves will strike land. "Tsunamis often destroy some coastal areas while leaving others with little damage," explained Tony Song of the NASA Jet Propulsion Laboratory, California Institute of Technology, at a 5 December press conference.

  1. Thermodynamic Self-Limiting Growth of Heteroepitaxial Islands Induced by Nonlinear Elastic Effect.

    PubMed

    Hu, Hao; Niu, Xiaobin; Liu, Feng

    2016-06-01

    We investigate nonlinear elastic effect (NLEF) on the growth of heteroepitaxial islands, a topic of both scientific and technological significance for their applications as quantum dots. We show that the NLEF induces a thermodynamic self-limiting growth mechanism that hinders the strain relaxation of coherent island beyond a maximum size, which is in contrast to indefinite strain relaxation with increasing island size in the linear elastic regime. This self-limiting growth effect shows a strong dependence on the island facet angle, which applies also to islands inside pits patterned in a substrate surface with an additional dependence on the pit inclination angle. Consequently, primary islands nucleate and grow first in the pits and then secondary islands nucleate at the rim around the pits after the primary islands reach the self-limited maximum size. Our theory sheds new lights on understanding the heteroepitaxial island growth and explains a number of past and recent experimental observations. PMID:27203611

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Tsunami Preparedness in Washington (video)

    USGS Publications Warehouse

    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.

  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. 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.

  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. Properties of electromagnetic fields generated by tsunami first arrivals: Classification based on the ocean depth

    NASA Astrophysics Data System (ADS)

    Minami, Takuto; Toh, Hiroaki; Tyler, Robert H.

    2015-04-01

    Tsunami flow coupled with the geomagnetic field generates electric currents and associated magnetic fields. Although electromagnetic (EM) tsunami signals can be used for analysis and even forecasting tsunami propagation, the dynamically self-consistent effect of shoaling water depth on the fluid + electrodynamics has not been adequately clarified. In this study, we classify tsunami EM phenomena into three cases based on the ocean depth and find that the deeper ocean results in stronger self-induction due to the increase in both tsunami phase velocity and ocean conductance. In this deep-ocean case, the phase lead of the vertical magnetic variation relative to the sea surface elevation is smaller, while an initial rise in the horizontal magnetic component becomes observable prior to tsunami arrival. Furthermore, we confirm that the enhancement of tsunami height in shallower oceans shifts the ocean depth supplying maximum amplitudes of tsunami magnetic fields from approximately 2.0 km to 1.5 km.

  12. Tsunamis: Water Quality

    MedlinePlus

    ... After a Tsunami Worker Safety After a Flood Pesticide Safety Guidance Epidemiologic Methods for Relief Operations MMWRs ... include fuel products from overturned fuel tanks, or pesticides that may have been stored in flooded areas. ...

  13. 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

  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. 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

  16. 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

  17. 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

  18. 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

  19. Update of the U.S. States and Territories National Tsunami Hazard Assessment: Historical Record and Sources for Waves

    NASA Astrophysics Data System (ADS)

    Dunbar, P. K.; Goldfinger, C.

    2013-12-01

    The NOAA-National Geophysical Data Center (NGDC) and the U.S. Geological Survey (USGS) collaborated to conduct the first qualitative United States tsunami hazard assessment, published in 2008 by the National Tsunami Hazard Mitigation Program (NTHMP). Since that time, significant events such as the 2009 Samoa and 2011 Tohoku tsunamis have affected the U.S. and reinforced the importance of considering all of the evidence when conducting an assessment. In addition, there has been progress in tsunami research that reduces some of the earlier uncertainties. In 2011, the National Academies released their assessment of the U.S. Tsunami Program recommending that NOAA and its NTHMP partners, in collaboration with researchers in social and physical sciences, should complete an initial national assessment of tsunami risk and should institute a periodic assessment of the sources of tsunamis that threaten the United States. Therefore, the NTHMP is updating the national tsunami hazard assessment. Although the second assessment will not be a national probabilistic tsunami hazard assessment, areas where there is progress in this methodology will be presented. As a result, a national tsunami vulnerability and risk assessment is not possible at this time, but examples of ongoing work will be presented. This paper looks at the data sources in the first report, including an examination of the NGDC historical tsunami database that resulted in a qualitative assessment based on the distribution of runup heights and the frequency of tsunami runups. Although tsunami deaths are a measure of risk rather than hazard, the known tsunami deaths were compared with the qualitative assessments based on frequency and amplitude. The 2009 American Samoa tsunami resulted in a change for the U.S. Pacific island territories qualitative tsunami hazard assessment from 'Moderate' to 'High'. The NGDC tsunami database contains reported tsunamis and is therefore limited to written records existing for an area

  20. 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. PMID:26392623

  1. 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

  2. Food Safety After a Tsunami

    MedlinePlus

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... be used to check food temperature. Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ...

  3. 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).

  4. Realtime Monitoring of Traveling Ionospheric Disturbances Caused by Tsunamis

    NASA Astrophysics Data System (ADS)

    McBride, P. J.; Crowley, G.; Reynolds, A.; Azeem, I.; Makela, J. J.; Vadas, S.

    2014-12-01

    The ocean-ionosphere coupling associated with tsunamis was predicted as early as the 1970s and had been observed previously by various radio frequency techniques, including arrays of ground-based Global Positioning System (GPS) receivers. Much work is still needed in order to fully understand the coupling mechanism and allow for the development of effective tsunami detection/warning systems. These challenges include the need for additional observations of the tsunami ionospheric signature to provide new scientific insight into the geophysical source phenomenology and wave propagation physics, and to better constrain the conditions under which ocean-atmospheric coupling is effective. One of the ionospheric signatures of tsunamis is a Traveling Ionospheric Disturbance (TID). ASTRA has developed a realtime TID Mapping System based on HF radio sounding. We will provide examples of TIDs associated with various tsunamis, including the propagation characteristics of the TIDs. We are deploying an expanded ground-based observation network using strategically placed optical imaging systems together with ASTRA's TID Mapping Systems, to obtain new information about the ionospheric waves associated with tsunamis. We will also use a published and validated gravity wave ray trace model to perform studies of the propagation of tsunami-generated gravity waves through the atmosphere and into the thermosphere/ionosphere system. This work will also enhance our understanding of upward coupling caused by all gravity wave sources in the lower atmosphere (not just tsunamis) and how this coupling can generate ionospheric irregularities that affect navigation, communications and surveillance systems.

  5. Effect of island shape on dielectrophoretic assembly of metal nanoparticle chains in a conductive-island-based microelectrode system

    NASA Astrophysics Data System (ADS)

    Ding, Haitao; Shao, Jinyou; Ding, Yucheng; Liu, Weiyu; Li, Xiangming; Tian, Hongmiao; Zhou, Yaopei

    2015-03-01

    The electrical conduction quality of an electric circuit connection formed by dielectrophoretic (DEP)-assembled metal nanoparticle wires between small conductive elements plays a significant role in electronic devices. One of the major challenges for improving the electrical conductance of nanowires is optimizing their geometric morphology. So far, the electrical conduction quality has been enhanced by optimizing the AC frequency and conductivity of nanoparticle suspensions. Herein, the effect of the conductive island shapes on the dynamic process occurring in a DEP assembly of 10 nm gold nanoparticles was investigated in a conductive-island-based microelectrode system. The nanoparticle wires between the microelectrodes were assembled in situ from colloidal suspensions. The wires were grown in a much straighter route by increasing the geometric angle of the conductive-island tip. To validate the experiments, the effects of mutual DEP interactions and electrothermally induced fluid flow on the dynamic behavior of particle motion for different island geometric configurations in the conductive-island-based microelectrode system were determined by numerical simulations. The simulation results are consistent with those of experiments. This indicates that different conductive island shapes change the distribution of DEP force and increase the electrothermally induced fluid flow to different extents in the vicinity, leading to different morphologies of DEP-assembled nanoparticle wires.

  6. 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

  7. 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

  8. A Reverse Tracking Method to Analyze the 1867 Keelung Tsunami Event

    NASA Astrophysics Data System (ADS)

    Lee, C.; Wu, T.; Tsai, Y.; KO, L.; Chuang, M.

    2013-12-01

    The 1867 Keelung tsunami is the only tsunami event verified by Taiwan government. This event caused serious damage and hundreds death toll in northern Taiwan, including the Keelung city, Jinshan and Patoutzu areas (Fig. 1). This event is not only recorded in many literatures, but also unveiled by sedimentary evidence. In addition, this event also indicates that the three nuclear power plants nearby are prone to tsunami attacks (Fig. 1). The previous studies consider that this tsunami might be generated by a Mw 7.0 earthquake which might occur along the Shanchiao Fault (Zheng et al, 2011). However, there is no evidence showing the relationship between these geological activities and the tsunami event. In this study, we intend to find the potential tsunami source through numerical analysis. We conducted series of numerical experiments by using sets of fault parameters from Mw 7.0 to Mw 8.0. However, none of them was able to explain the 7 m tsunami height observed in history and the sedimentary evidence found on the Hoping Island. Considering the steep bathymetry and intense volcanic activity along the Keelung coast, one reasonable hypothesis is that the earthquake or volcanic eruption triggered a submarine landslide which increased the tsunami height dramatically. In order to confirm this scenario, we performed the Reverse Tracking Method (RTM), based on the linear hypothesis of tsunami wave propagation, to find the possible locations of the tsunami sources (Fig. 1). The Cornell Multi-grid Coupled Tsunami Model (COMCOT) was then used to perform the tsunami simulations. We followed the Mw 7.0 earthquake proposed by Lin et al. (2006) and added the landslide disturbance (Watts et al., 2005). The source-scaling relationship proposed by Yen and Ma (2011) was used to determine the fault parameters. In addition to the Shanchiao Fault, five submarine volcanos and three submarine canyons were considered as the potential tsunami sources. The result shows that the 1867 tsunami

  9. Local tsunamis and earthquake source parameters

    USGS Publications Warehouse

    Geist, Eric L.

    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.

  10. 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

  11. 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

  12. Preliminary Simulation Results of the 23 June, 2001 Peruvian Tsunami

    NASA Astrophysics Data System (ADS)

    Titov, V. V.; Koshimura, S.; Ortiz, M.; Borrero, J.

    2001-12-01

    The tsunami generated by the June 23, 2001 Peruvian earthquake devastated a 50--km section of coast near the earthquake epicenter and was recorded on tide-gages throughout the Pacific. The coastal town of Camana sustained the most damage with tsunami waves penetrating up to 1--km inland and runup exceeding 5--m. The extreme local effects and widespread impact motivated modeling efforts to produce a realistic tsunami simulation of this event. Preliminary results were produced by the TIME center using two resident numerical models, TUNAMI--2 and MOST. Both models were used to produce preliminary simulations shortly after the earthquake, and first results were posted on the Internet a day after the event (http://www.pmel.noaa.gov/tsunami/peru_pmel.html). These numerical results aimed to quantify the magnitude of the tsunami and, to certain extent, to guide the post-tsunami survey. The first simulations have been revised using new data about the seismic source and the results of the post-tsunami survey. Measured inundation distances, flow depths, and runup along topographic transects are used to constrain the inundation model. Preliminary numerical analysis of tsunami inundation will be presented.

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

    USGS Publications Warehouse

    Ross, Stephanie, (Edited By); 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.

  14. 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.

  15. Tsunami Generation Modelling for Early Warning Systems

    NASA Astrophysics Data System (ADS)

    Annunziato, A.; Matias, L.; Ulutas, E.; Baptista, M. A.; Carrilho, F.

    2009-04-01

    parameters available right after an earthquake are preliminary and could be inaccurate. Determining which earthquake source parameters would affect the initial height and time series of tsunamis will show the sensitivity of the tsunami time series to seismic source details. Therefore a new fault generation model will be adopted, according to the seismotectonics properties of the different regions, and finally included in the calculation scheme. In order to do this, within the collaboration framework of Portuguese authorities, a new model is being defined, starting from the seismic sources in the North Atlantic, Caribbean and Gulf of Cadiz. As earthquakes occurring in North Atlantic and Caribbean sources may affect Portugal mainland, the Azores and Madeira archipelagos also these sources will be included in the analysis. Firstly we have started to examine the geometries of those sources that spawn tsunamis to understand the effect of fault geometry and depths of earthquakes. References: Annunziato, A., 2007. The Tsunami Assesment Modelling System by the Joint Research Center, Science of Tsunami Hazards, Vol. 26, pp. 70-92. Mader, C.L., 1988. Numerical modelling of water waves, University of California Press, Berkeley, California. Ward, S.N., 2002. Tsunamis, Encyclopedia of Physical Science and Technology, Vol. 17, pp. 175-191, ed. Meyers, R.A., Academic Press.

  16. Geologic evidence for a tsunami source along the trench northeast of Puerto Rico

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Coral boulders of medieval age at Anegada, British Virgin Islands, calibrated to local geologic effects of far-field tsunamis and hurricanes, provide tangible evidence for the generation of a tsunami by faulting along the eastern Puerto Rico Trench. SETTING: Anegada is 120 km south of the Puerto Rico Trench and 200 km east-northeast of San Juan. It is fringed on the north and east by a coral reef 100-1200 m offshore; founded on Pleistocene carbonate with a cemented cap; rimmed on much of its perimeter by sandy Holocene beach ridges; and bermed with coral-rubble on a rocky stretch of its north shore. CORAL BOULDERS: Scores of coral heads up to 2 m in diameter were moved across the north shore in medieval time. Some crossed the line of the modern storm berm, continued over a limestone rise 4 m above sea level, and came to rest on lower ground hundreds of meters farther south. Others traversed beach ridges, and two of these boulders are now 1.5 km from the fringing reef. Most of the boulders are Diploria strigosa, an endemic of reef flanks. Some retain enough of their originally rounded, dimpled shape to have been deposited live. The likely time of emplacement of freshly dislodged, still-living heads is AD 1200-1450. This range is based on radiocarbon dating of outer growth bands of 18 heads from 5 separate areas. The youngest of the ages is 890±25 14C yr BP, and the ΔR assumed is 0 to -200 14C yr. CALIBRATION TO A FAR-FIELD TSUNAMI: Deposits dated to 1650-1800 at Anegada represent either the largest known far-field tsunami in the Caribbean (1755 Lisbon) or some other tsunami or unusual storm that surpassed the Lisbon tsunami in its local geologic effects. The water cut or freshened breaches in north-shore beach ridges and poured into a marine pond, where it moved limestone boulders and laid down a sheet of sand and shell that extends as much as 1.5 km inland [refs 1-4]. Many of the limestone boulders were probably inherited from the higher, earlier overwash that

  17. 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

  18. 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

  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. 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

  1. The 1843 earthquake: a maximising scenario for tsunami hazard assessment in the Northern Lesser Antilles?

    NASA Astrophysics Data System (ADS)

    Roger, Jean; Zahibo, Narcisse; Dudon, Bernard; Krien, Yann

    2013-04-01

    The French Caribbean Islands are located over the Lesser Antilles active subduction zone where a handful of earthquakes historically reached magnitude Mw=6.0 and more. According to available catalogs these earthquakes have been sometimes able to trigger devastating local or regional tsunamis, either directly by the shake or indirectly by induced landslides. For example, these islands have severely suffered during the Mw~7.5 Virgin Islands earthquake (1867) triggering several meters high waves in the whole Lesser Antilles Arc and, more recently, during the Mw=6.3 Les Saintes earthquake (2004) followed by a local 1 m high tsunami. However, in 1839 a Mw~7.5 subduction earthquake occured offshore Martinica followed a few years after by the more famous 1843 Mw~8.5 megathrust event, with an epicenter located approximately between Guadeloupe and Antigua, but both without any catastrophic tsunami being reported. In this study we discuss the potential impact of a maximum credible scenario of tsunami generation with such a Mw=8.5 rupture at the subduction interface using available geological information, numerical modeling of tsunami generation and propagation and high resolution bathymetric data within the framework of tsunami hazard assessment for the French West Indies. Despite the fact that the mystery remains unresolved concerning the lack of historical tsunami data especially for the 1843 event, modeling results show that the tsunami impact is not uniformly distributed in the whole archipelago and could show important heterogeneities in terms of maximum wave heights for specific places. This is easily explained by the bathymetry and the presence of several islands around the mainland leading to resonance phenomena, and because of the existence of a fringing coral reef surrounding partially those islands.

  2. 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

  3. 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

  4. Numerical Study on the 1682 Tainan Historic Tsunami Event

    NASA Astrophysics Data System (ADS)

    Tsai, Y.; Wu, T.; Lee, C.; KO, L.; Chuang, M.

    2013-12-01

    We intend to reconstruct the tsunami source of the 1682/1782 tsunami event in Tainan, Taiwan, based on the numerical method. According to Soloviev and Go (1974), a strong earthquake shook the Tainan and caused severe damage, followed by tsunami waves. Almost the whole island was flooded by tsunami for over 120 km. More than 40,000 inhabitants were killed. Forts Zealand and Pigchingi were washed away. 1682/1782 event was the highest death toll in the Pacific Ocean regarded by Bryant (2001). However, the year is ambiguous in 1682 or 1782, and death toll is doubtful. We tend to believe that this event was happened in 1682 based on the evolution of the harbor name. If the 1682 tsunami event does exist, the hazard mitigation plan has to be modified, and restoring the 1682 event becomes important. In this study, we adopted the tsunami reverse tracking method (TRTM) to examine the possible tsunami sources. A series of numerical simulations were carried out by using COMCOT (Cornell Multi-grid Coupled Tsunami model), and nested grid with 30 m resolution was applied to the study area. According to the result of TRTM, the 1682 tsunami is most likely sourcing from the north segment of Manila Trench. From scenario study, we concluded that the 1682 event was triggered by an Mw >= 8.8 earthquake in north segment of Manila Trench, and 4 m wave height was observed in Tainan and its inundation range is agreeable with historical records. If this scenario occurred again, sever damage and death toll will be seen many high population cities, such as Tainan city, Kaohsiung city and Kenting, where No. 3 nuclear power plant is located. Detailed results will be presented in the full paper. Figure 1. Map of Tsunami Reverse Tracking Method (TRTM) in Tainan. Black arrow indicates direction of possible tsunami direction. The color bar denotes the magnitude of the maximum moment flux. Figure 2. Scenario result of Mw 8.8 in northern segment of Manila Trench. (Left: Initial free surface elevation

  5. 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

  6. Geological overview of the 2011 Tohoku-Oki tsunami in Japan

    NASA Astrophysics Data System (ADS)

    Goto, K.

    2011-12-01

    The 11 March 2011 Mw 9.0 Tohoku-Oki Earthquake off the coast of northeast Japan generated a major tsunami (herein after the 2011 Tohoku-Oki tsunami) that inundated wide area of the northeast coast of Honshu. Remarkable feature of the northeast coast of Honshu is the abundance of available records for the past earthquakes and tsunamis with 1200 years of written history and ~3800 years of geological evidence. According to the historical record of the great tsunami at AD869 (the Jogan tsunami), the tsunami flooded the Sendai plain and over 1000 peoples were drowned. The geological record of the Jogan event, characterized by a thin marine sand layer provides evidence for tsunami inundation at least 3 km inland from the paleo-coastline. Geological evidence also extends back further in time with older sand layers probably deposited by paleo-tsunamis found beneath the Jogan event, leading scientists to estimate a recurrence interval of 600 to 1300 years for large tsunamis in the region [Minoura and Nakaya, 1991; Sawai et al., 2008]. The 2011 event might have confirmed this estimated recurrence interval. The geological surveys of the 2011 Tohoku-Oki tsunami was quickly started after the early April by Japanese and international researchers in order to clarify the sedimentological, geomorphological, and geochemical effects of the tsunami. Especially, the comprehensive video coverage is available in some area, thus allowing comparison of local flow variations with deposit characteristics. Moreover, the tsunami inundated with various distance up to 5 km inland and hence it is possible to compare the relationship between the landward extent of the deposit and the tsunami inundation limit. Here, I report the overview of the current understanding of the geological aspects of the 2011 Tohoku-Oki tsunami and its implication to the paleo-tsunami events in the area.

  7. 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.

  8. Effect of island size, distance, and epicenter maturity on colonization in freshwater protozoan communities

    SciTech Connect

    Henebry, M.S.; Cairns, J. Jr.

    1980-07-01

    The purpose of this study was to: (a) obtain baseline data on the colonization of artificial islands in a closed laboratory system; (b) investigate effects of island area and distance from an epicenter (source of protozoa) on the colonization process, and (c) test the effect of the maturity of an epicenter on the colonization of surrounding islands. Islands which were smallest in area or closest to the epicenter had significantly greater species richness during the 7 days of the experiments. Islands exposed to epicenters of intermediate, maturity had significantly greater species richness than islands tested with mature (fully colonized) epicenters. Evidence gathered thus far strongly suggests that kinds of species during different periods of colonization are responsible for differences in species richness on islands exposed to epicenters of different maturities.

  9. Monitoring the Surface Heat Island (shi) Effects of Industrial Enterprises

    NASA Astrophysics Data System (ADS)

    Şekertekin, A.; Kutoglu, Ş. H.; Kaya, S.; Marangoz, A. M.

    2016-06-01

    The aim of this study is to present the effects of industrial enterprises on Land Surface Temperature (LST) and to retrieve Surface Heat Island (SHI) maps of these regions. SHI is one of the types of Urban Heat Island (UHI) and as the urban areas grow in a city, UHI effect becomes bigger. The city centre of Zonguldak was chosen as study area and Landsat 5 satellite data were used as materials. Zonguldak has important industrial enterprises like thermal power plants and iron and steel plant. ERDEMIR is the biggest iron and steel plant in Turkey and it is one of the biggest ones in Europe, as well. There are three operating thermal power plants in the region namely CATES, ZETES1 and ZETES2. In order to investigate these industrial regions, Landsat 5 satellite data were processed using mono-window algorithm to retrieve LST and they were acquired on 11.09.1987, 18.09.2007 and 29.09.2011, respectively. The obtained results revealed that from 1987 to 2011, spatial and temporal variability in LST in industrial enterprises became higher than the surroundings. Besides, the sizes of SHIs in 2011 are bigger than the ones in 1987. For the countries and governments, having industrial enterprises is crucial for the development and it is also important to present the community better conditions in life. Thus, decision makers should consider mitigating the effects of these regions on LST.

  10. Numerical simulation of the 2002 Northern Rhodes Slide (Greece) and evaluation of the generated tsunami

    NASA Astrophysics Data System (ADS)

    Zaniboni, Filippo; Armigliato, Alberto; Pagnoni, Gianluca; Tinti, Stefano

    2013-04-01

    Small landslides are very common along the submarine margins, due to steep slopes and continuous material deposition that increment mass instability and supply collapse occurrences, even without earthquake triggering. This kind of events can have relevant consequences when occurring close to the coast, because they are characterized by sudden change of velocity and relevant speed achievement, reflecting into high tsunamigenic potential. This is the case for example of the slide of Rhodes Island (Greece), named Northern Rhodes Slide (NRS), where unusual 3-4 m waves were registered on 24 March 2002, provoking some damage in the coastal stretch of the city of Rhodes (Papadopoulos et al., 2007). The event was not associated with earthquake occurrence, and eyewitnesses supported the hypothesis of a non-seismic source for the tsunami, placed 1 km offshore. Subsequent marine geophysical surveys (Sakellariou et al., 2002) evidenced the presence of several detachment niches at about 300-400 m depth along the northern steep slope, one of which can be considered responsible of the observed tsunami, fitting with the previously mentioned supposition. In this work, that is carried out in the frame of the European funded project NearToWarn, we evaluated the tsunami effects due to the NRS by means of numerical modelling: after having reconstructed the sliding body basing on morphological assumptions (obtaining an esteemed volume of 33 million m3), we simulated the sliding motion through the in-house built code UBO-BLOCK1, adopting a Lagrangian approach and splitting the sliding mass into a "chain" of interacting blocks. This provides the complete dynamics of the landslide, including the shape changes that relevantly influence the tsunami generation. After the application of an intermediate code, accounting for the slide impulse filtering through the water depth, the tsunami propagation in the sea around the island of Rhodes and up to near coasts of Turkey was simulated via the

  11. The footprint of urban heat island effect in China.

    PubMed

    Zhou, Decheng; Zhao, Shuqing; Zhang, Liangxia; Sun, Ge; Liu, Yongqiang

    2015-01-01

    Urban heat island (UHI) is one major anthropogenic modification to the Earth system that transcends its physical boundary. Using MODIS data from 2003 to 2012, we showed that the UHI effect decayed exponentially toward rural areas for majority of the 32 Chinese cities. We found an obvious urban/rural temperature "cliff", and estimated that the footprint of UHI effect (FP, including urban area) was 2.3 and 3.9 times of urban size for the day and night, respectively, with large spatiotemporal heterogeneities. We further revealed that ignoring the FP may underestimate the UHI intensity in most cases and even alter the direction of UHI estimates for few cities. Our results provide new insights to the characteristics of UHI effect and emphasize the necessity of considering city- and time-specific FP when assessing the urbanization effects on local climate. PMID:26060039

  12. The footprint of urban heat island effect in China

    NASA Astrophysics Data System (ADS)

    Zhou, Decheng; Zhao, Shuqing; Zhang, Liangxia; Sun, Ge; Liu, Yongqiang

    2015-06-01

    Urban heat island (UHI) is one major anthropogenic modification to the Earth system that transcends its physical boundary. Using MODIS data from 2003 to 2012, we showed that the UHI effect decayed exponentially toward rural areas for majority of the 32 Chinese cities. We found an obvious urban/rural temperature “cliff”, and estimated that the footprint of UHI effect (FP, including urban area) was 2.3 and 3.9 times of urban size for the day and night, respectively, with large spatiotemporal heterogeneities. We further revealed that ignoring the FP may underestimate the UHI intensity in most cases and even alter the direction of UHI estimates for few cities. Our results provide new insights to the characteristics of UHI