Potential Tsunami Research Articles

Disentangling the history of complex multi-phased shell beds based on the analysis of 3D point cloud data

Abstract We present the largest GIS-based data set of a single shell bed, comprising more than 10,280 manually outlined objects. The data are derived from a digital surface model based on high-resolution terrestrial laser scanning (TLS) and orthophotos obtained by photogrammetric survey, with a sampling distance of 1 mm and 0.5 mm, respectively. The shell bed is an event deposit, formed by a tsunami or an exceptional storm in an Early Miocene estuary. Disarticulated shells of the giant oyster Crassostrea gryphoides are the most frequent objects along with venerid, mytilid and solenid bivalves and potamidid gastropods. The contradicting ecological requirements and different grades of preservation of the various taxa mixed in the shell bed, along with a statistical analysis of the correlations of occurrences of the species, reveal an amalgamation of at least two pre- and two post-event phases of settlement under different environmental conditions. Certain areas of the shell bed display seemingly significant but opposing shell orientations. These patterns in coquinas formed by densely spaced elongate shells may result from local alignment of neighboring valves due to occasional events and bioturbation during the years of exposure. Similarly, the patchy occurrence of high ratios of shells in stable convex-up positions may simply be a result of such “maturity” effects. Finally, we document the difficulties in detecting potential tsunami signatures in shallow marine settings even in exceptionally preserved shell beds due to taphonomic bias by post-event processes.

Fast determination of earthquake magnitude and fault extent from real-timeP-wave recordings

S U M M A R Y This work is aimed at the automatic and fast characterization of the extended earthquake source, through the progressive measurement of the P-wave displacement amplitude along the recorded seismograms. We propose a straightforward methodology to quickly characterize the earthquake magnitude and the expected length of the rupture, and to provide an approximate estimate of the average stress drop to be used for Earthquake EarlyWarning and rapid response purposes. We test the methodology over a wide distance and magnitude range using a massive Japan earthquake, accelerogram data set. Our estimates of moment magnitude, source duration/length and stress drop are consistent with the ones obtained by using other techniques and analysing the whole seismic waveform. In particular, the retrieved source parameters follow a self-similar, constant stress-drop scaling (median value of stress drop = 0.71 MPa). For the M 9.0, 2011 Tohoku-Oki event, both magnitude and length are underestimated, due to limited, available P-wave time window (PTWs) and to the low-frequency cut-off of analysed data. We show that, in a simulated real-time mode, about 1–2 seconds would be required for the source parameter determination of M 4–5 events, 3–10 seconds for M 6–7 and 30–40 s for M 8–8.5. The proposed method can also provide a rapid evaluation of the average slip on the fault plane, which can be used as an additional discriminant for tsunami potential, associated to large magnitude earthquakes occurring offshore.

Potential risk analysis on a Jianchuandong dangerous rockmass-generated impulse wave in the Three Gorges Reservoir, China

An impulse wave generated by landslide is a major detriment to waterway safety in reservoirs. Thick-bedded pillar-shaped rockmass is one of the principal potential tsunami generators in the Three Gorges Reservoir and other reservoirs around the world. However, the impulse wave generated by a pillar-shaped rockmass was seldom studied in the past. The Jianchuandong dangerous rockmass lies on the left bank of Yangtze River in the Wu Gorge of the Three Gorges Reservoir with a total volume of 36 × 104 m3 or so, standing as a serious threat to the safety of the waterway, a renowned “expressway”. Along with the deterioration of the base mass, the Jianchuandong rockmass is likely to either slide or topple due to instability. A solid–fluid coupled computational fluid dynamic model is built to calculate the potential impulse wave induced by the Jianchuandong dangerous rockmass. The potential impulse waves under four working conditions with two failure modes and two water levels are discussed. Numerical simulation results show that the potential maximum wave height and maximum run-up are 47.1 and 27.2 m, respectively. Based on the integrated calculation results, we deduce a 15 km channel segment likely to be affected by the Jianchuandong rockmass-induced impulse wave for early warning purpose. By engineering geological analogy, the calculation results are verified with the instance data of two impulse wave events generated by landslides in the Three Gorges Reservoir. The purpose of this study is to provide a technical support for early warning, prevention and control of hazards associated with the Jianchuandong dangerous rockmass and to serve as a reference for researches on impulse wave generated by pillar-shaped rockmass collapse around the world.

Aftereffects of Subduction-Zone Earthquakes: Potential Tsunami Hazards along the Japan Sea Coast.

The 2011 Tohoku-Oki Earthquake is a typical subduction-zone earthquake and is the 4th largest earthquake after the beginning of instrumental observation of earthquakes in the 19th century. In fact, the 2011 Tohoku-Oki Earthquake displaced the northeast Japan island arc horizontally and vertically. The displacement largely changed the tectonic situation of the arc from compressive to tensile. The 9th century in Japan was a period of natural hazards caused by frequent large-scale earthquakes. The aseismic tsunamis that inflicted damage on the Japan Sea coast in the 11th century were related to the occurrence of massive earthquakes that represented the final stage of a period of high seismic activity. Anti-compressive tectonics triggered by the subduction-zone earthquakes induced gravitational instability, which resulted in the generation of tsunamis caused by slope failing at the arc-back-arc boundary. The crustal displacement after the 2011 earthquake infers an increased risk of unexpected local tsunami flooding in the Japan Sea coastal areas.

Implementation and Challenges of the Tsunami Warning System in the Western Mediterranean

The French Tsunami Warning Center (CENALT) has been in operation since 2012. It is contributing to the North-eastern and Mediterranean (NEAM) tsunami warning and mitigation system coordinated by the United Nations Educational, Scientific, and Cultural Organization, and benefits from data exchange with several foreign institutes. This center is supported by the French Government and provides French civil-protection authorities and member states of the NEAM region with relevant messages for assessing potential tsunami risk when an earthquake has occurred in the Western Mediterranean sea or the Northeastern Atlantic Ocean. To achieve its objectives, CENALT has developed a series of innovative techniques based on recent research results in seismology for early tsunami warning, monitoring of sea level variations and detection capability, and effective numerical computation of ongoing tsunamis.

A Potential Tsunami impact assessment of submarine landslide at Baiyun Depression in Northern South China Sea

Abstract Background With mature hydrocarbon industry, Northern South China Sea (NSCS) is a hot spot for future economic development. However, the local government and researchers lack of estimations about damages brought by a submarine landslide-generated tsunami. According to oceanographic surveys, eleven landslides in different scale have been discovered in Baiyun Depression of NSCS. Hence, the need to study potential tsunamis generated by submarine landslides in NSCS is urgent and necessary. This research, focused on potential threat linked to local tsunami sources, is in its early stage in China but it is of capital importance for the local people, local government and offshore economics. Finding Taking landslide S4 for example, the formation, spreading and run-up are predicted. As calculated, the greatest height of tsunami generated by Landslide S4 is 17.5 m, occurring near Dongsha Islands, and the greatest run-up formed on the coastal line is 5.3 m, occurring near Shanwei City; the general height of waves attacking the coastal line is no more than 1.5m, but abnormally high waves might occur in 32 regions. Conclusions Prediction of tsunami generated by Landslide S4 suggests that local landslides in NSCS may trigger tsunami hazards. Therefore, more efforts shall be made to investigate potential damages caused by a submarine landslide, particularly the submarine landslides at Baiyun Depression in NSCS.

Silurian carbonate high-energy deposits of potential tsunami origin: Distinguishing lateral redeposition and time averaging using carbon isotope chemostratigraphy

Stable carbon isotope curves are used as a precise stratigraphic tool in the Paleozoic, even though they are commonly based on shallow-water carbonate record, characterized by low stratigraphic completeness. Identification of episodes of large-scale redeposition and erosion may improve δ13Ccarb-based correlations. Here, a series of at least three episodes of high-energy onshore redeposition are described from the Makarivka Member (new unit) of the Ustya Formation from the Homerian (middle Silurian) of Podolia, Ukraine. The Makarivka Member is emplaced within a tidal flat succession. Its most prominent part is divided into a lower polymictic conglomerate of sand- to boulder-sized clasts representing a range of subtidal facies, and an upper heterolithic unit composed of grainstone and mudstone laminae. The aim of the study is to identify the mechanism of deposition of the allochthonous conglomeratic material in this Member. Based on analogies with recent tsunami deposits, the conglomerate is interpreted to reflect the strongest landward-directed current in the tsunami run-up phase, and the heterolith — alternating high-density landward currents, stagnant intervals allowing mud and land-derived debris to settle, and backwash flows. The tsunamite was deposited during an interval of decreasing isotopic values of the Mulde excursion, a global δ13C excursion reaching +5.2‰ in the studied sections. Clast redeposition in an interval characterized by rapidly changing δ13Ccarb offers the opportunity to evaluate the degree of temporal and spatial averaging caused by the tsunami. The clasts in the polymictic conglomerate show scattered δ13Ccarb values (−0.3‰ to +2.1‰) compared to homogenous (1.3‰ to 1.6‰) values in the matrix. The presence of clasts characterized by low δ13Ccarb values is explained by their decrease with bathymetry rather than erosion of pre-excursion strata, whereas high values characterize material entrained from the sea-floor and strata directly underlying the tsunamite. Close (1.3‰ and 1.5‰) average δ13Ccarb values suggest that the matrix of the conglomerate is potentially a product of clast grinding.

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

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.

Tsunami hazard assessment of Chabahar bay related to megathrust seismogenic potential of the Makran subduction zone

Tsunami inundation mapping is the first step in the development of effective evacuation plans for communities at risk. These maps also provide bases for land use planners in communities to reduce risk by locating critical facilities out of the potential tsunami flood plain. The Makran subduction zone, located off the Indian Ocean coasts of Iran and Pakistan, is an important tsunamigenic zone for the region. On the 27th November, 1945, it was the site of a major earthquake with a moment magnitude of 8.1 and killed about 4,000 people. This event is a proof that Makran coastal areas are unsafe since the tsunami is quite probable. The objective of this study was providing tsunami inundation and hazard maps in Chabahar bay which is located in South East of Iran and the northern coast of Oman Sea. Three different source magnitude scenarios along Makran subduction zone are considered and for each scenario, numerical modeling of tsunami propagation is performed using MIKE 21 FM numerical software. Because the Makran subduction zone is very close to the Chabahar bay, unstructured triangular mesh with a higher level of refinement closer to the area of interest was used so that the tsunami was not numerically dissipated. After analyzing the data obtained from the results, inundation maps were produced, and by combining these maps, tsunami hazard map was provided for the bay. Tsunami wave amplification has been observed mainly in the outer coasts of the bay where the uplifted rocky shore experience up to 18 m wave height. Chabahar bay omega form and two eastern and western headlands cause a considerable depreciation in tsunami wave. Longer distance of coasts within the bay is another reason of tsunami depreciation inside the bay. Based on the generated inundation and hazard maps, two flood zones are specified. The first zone associated with no inundation or low inundation on cliffy shores, and the second zone would experience extensive inundation on the coast of kenarak areas, areas with sandy beaches and gentle slope.

An Investigation on Multi-Buoy Inversion Method for Tsunami Warning System in South China Sea

The key technologies for the development of tsunami warning system include the establishment of tsunami database and inversion method for evaluating source parameters of earthquake by monitored wave data. A tsunami model based on the shallow water equations is adopted to simulate the 2011 Tohoku tsunami to validate the numerical model of generation and propagation of tsunami. The numerical results match well with measured data by DART buoys in terms of the wave height and the arrival time of the tsunami. For the potential earthquake source in the Manila Trench, the numerical model is used to compute the elementary wave fields triggered by unit sources of potential tsunami source with unit slip. Using the tsunami database derived by the elementary wave fields, an inversion method for plate slip based on multi-buoy measurements is applied to compute the time series of surface elevation at the given locations around the coasts in the South China Sea region. Through numerical simulations and multi-buoy inversion computation, the inversed time series of wave profile induced by earthquakes with the magnitudes Mw= 8.0, 8.5, 8.8, 9.35 are obtained. The comparisons of the inversion results and direct simulation data show good agreement. It turns out that, the multi-buoy inversion method works well and, according to the numerical results, deploying one or two buoys along the west side of the Manila Trench is necessary to provide tsunami warning information for the west coasts in the South China Sea. It is suggested that we should deploy one buoy between the south part of Taiwan and the north end of the Manila Trench subduction zone so that we could obtain a good predicted wave height at the south part of Taiwan by the multi-buoy inversion method.

New Tsunami Forecast Tools for the French Polynesia Tsunami Warning System

This paper presents the tsunami warning tools, which are used for the estimation of the seismic source parameters. These tools are grouped under a method called Preliminary Determination of Focal Mechanism_2 (PDFM2), that has been developed at the French Polynesia Warning Center, in the framework of the \(SEISCOMP3\) system, as a plug-in concept. The first tool determines the seismic moment and the focal geometry (strike, dip, and slip), and the second tool identifies the ”tsunami earthquakes” (earthquakes that cause much bigger tsunamis than their magnitude would imply). In a tsunami warning operation, initial assessment of the tsunami potential is based on location and magnitude. The usual quick magnitude methods which use \(P\) waves, work fine for smaller earthquakes. For major earthquakes these methods drastically underestimate the magnitude and its tsunami potential because the radiated energy shifts to the longer period waves. Since French Polynesia is located far away from the subduction zones of the Pacific rim, the tsunami threat is not imminent, and this luxury of time allows to use the long period surface wave data to determine the true size of a major earthquake. The source inversion method presented in this paper uses a combination of surface waves amplitude spectra and P wave first motions. The advantage of using long period surface data is that there is a much more accurate determination of earthquake size, and the advantage of using P wave first motion is to have a better constrain of the focal geometry than using the surface waves alone. The \(PDFM2\) method routinely gives stable results at \(T_0 + 45\) minutes, with \(T_0\) being the origin time of an earthquake. Our results are then compared to the Global Centroid Moment Tensor catalog for validating both the seismic moment and the source geometry. The second tool discussed in this paper is the slowness parameter \(\theta,\) and is the energy-to-moment ratio. It has been used to identify tsunami earthquakes, which are characterized by having unusual slow rupture velocity and release seismic energy that has been shifted to longer periods and, therefore, have low \(\theta\) values. The slow rupture velocity would indicate weaker material and bigger uplift and, thus, bigger tsunami potential. The use of the slowness parameter \(\theta\) is an efficient tool for monitoring the near real-time identification of tsunami earthquakes.

Tsunami Hazards along the Eastern Australian Coast from Potential Earthquakes: Results from Numerical Simulations

Australia is surrounded by the Pacific Ocean and the Indian Ocean and, thus, may suffer from tsunamis due to its proximity to the subduction earthquakes around the boundary of Australian Plate. Potential tsunami risks along the eastern coast, where more and more people currently live, are numerically investigated through a scenario-based method to provide an estimation of the tsunami hazard in this region. We have chosen and calculated the tsunami waves generated at the New Hebrides Trench and the Puysegur Trench, and we further investigated the relevant tsunami hazards along the eastern coast and their sensitivities to various sea floor frictions and earthquake parameters (i.e. the strike, the dip and the slip angles and the earthquake magnitude/rupture length). The results indicate that the Puysegur trench possesses a seismic threat causing wave amplitudes over 1.5 m along the coast of Tasmania, Victoria, and New South Wales, and even reaching over 2.6 m at the regions close to Sydney, Maria Island, and Gabo Island for a certain worse case, while the cities along the coast of Queensland are potentially less vulnerable than those on the southeastern Australian coast.

Assessing Building Vulnerability to Tsunami Hazard in Padang

It may be necessary to carry out a study about risk analysis of building vulnerability to tsunami hazard in order to identify and develop potential tsunami risk in a coastal community. The objective of this study is to develop a risk analysis of building vulnerability to tsunami hazard in Parupuk Tabing, Padang. The study aims to: (1) identify and develop the building vulnerability of various building types to tsunami hazard; (2) simulate the tsunami propagation; and (3) develop risk analysis of building vulnerability to tsunami hazard in Padang. Risk level is determined by relative vulnerabilty index score of each building to a tsunami. The buildings were classified in five classes (very low risk, low, medium, high and very high). The method used to analize pattern of various types of building and tsunami inundation is by applying formulas in the field and simulating an earthquake with TUNAMI N3 Imamura method respectively. Clearly, the relative vulnerability index ranges of the building samples in Parupuk Tabing are from 3 to 5 (medium, high and very high risk). This study shows that risk components for building protection are around 30 to 40%, whereas water inundation is 33.33%, followed by building vulnerability of 22.67-33.67%. It can be estimated that, the condition can be very vulnerable, if the level of water is more than 2 m around a building and the vulnerability of water is around 33%. The results of this study contribute to the development of risk management strategies in designing of building and construction standards as well as plan for vertical evacuation and land use zones in order to mitigate the impact of tsunami disaster in coastal communities of Padang.

New Insights into the Emplacement Dynamics of Volcanic Island Landslides

Volcanic islands form the highest topographic structures on Earth and are the sites of some of the planet's largest landslides. These landslides can rapidly mobilize hundreds of cubic kilometers of rock and sediment, and potentially generate destructive tsunamis on ocean-basin scales. The main unknown for tsunami hazard assessment is the way in which these landslides are emplaced. Understanding of landslide dynamics relies on interpretation of deposits from past events: it is necessary to understand where material within the deposit originated and the temporal sequence of the deposit's formation. The degree of fragmentation in a volcanic landslide is controlled by its relative proportions of dense lavas and weak pyroclastic rocks; fragmentation is generally reduced during subaqueous relative to subaerial transport. In the submarine environment, the seafloor-sediment substrate commonly fails during emplacement of a volcanic landslide. However, in many cases, this sediment failure remains almost in situ as a deformed package rather than disaggregating to form a debris flow. Because seafloor sediment makes up a large proportion of many landslide deposits around volcanic islands, the magnitude of the primary volcanic failure cannot be readily assessed without a clear understanding of deposit constituents. Both the dimensions of the volcanic failure and the way in which it fails are of key importance for tsunami generation. Turbidite deposits suggest that some volcanic landslides occur in multiple retrogressive stages. This significantly reduces potential tsunami magnitude relative to models that assume emplacement of the landslide in a single stage.

Earthquake and Tsunami Potential of the Hikurangi Subduction Thrust, New Zealand: Insights from Paleoseismology, GPS, and Tsunami Modeling

Earthquake and Tsunami Potential of the Hikurangi Subduction Thrust, New Zealand: Insights from Paleoseismology, GPS, and Tsunami Modeling

Radiated Energy of Great Earthquakes from Teleseismic Empirical Green’s Function Deconvolution

We expand on the empirical Green’s function deconvolution method of Ide et al. (2011) to estimate radiated energy for the six largest earthquakes worldwide over the last 10 years: 2011 M w 9.0 Tohoku-Oki, 2004 M w 9.1 Sumatra, 2010 M w 8.8 Maule, 2005 M w 8.7 Nias, 2007 M w 8.5 Bengkulu, and 2012 M w 8.6 off-Sumatra. Deconvolution of P, SV and SH components gives consistent energy results that are comparable to estimates found independently by other researchers. Apparent stress for the five great thrust earthquakes is between 0.4 and 0.8 MPa, while the 2012 off-Sumatra strike-slip earthquake has a higher apparent stress of 3 MPa, which is consistent with other studies that find a tendency for strike-slip events to be more energetic. Our results are within the spread of apparent stress from the wider global earthquake population over a large magnitude range. The azimuthal distribution of energy in each case shows signs of directivity, and in some cases, shows less energy radiated in the trench-ward direction, which may suggest enhanced tsunami potential. We find that eGfs as small as ~M 6.5 can be used for teleseismic deconvolution, and that an eGf-mainshock magnitude difference of 1.5 units yields stable results. This implies that M 8 is the minimum mainshock size for which teleseismic eGf deconvolution will work well. We propose that a database of eGf events could be used to calculate radiated energy and apparent stress of great, hazardous events in near real time, i.e., promptly enough that it could contribute to rapid response measures.

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

Abstract. A post-hurricane survey of a Caribbean island affords comparisons with geologic evidence for greater overwash at the same place. This comparison, though of limited application to other places, helps calibrate coastal geology for assessment of earthquake and tsunami potential along the Antilles Subduction Zone. The surveyed island, Anegada, is 120 km south of the Puerto Rico Trench and is near the paths of hurricanes Donna (1960) and Earl (2010), which were at or near category 4 when at closest approach. The survey focused on Earl's geologic effects, related them to the surge from Hurricane Donna, and compared them further with erosional and depositional signs of southward overwash from the Atlantic Ocean that dates to 1200–1450 AD and to 1650–1800 AD. The main finding is that the geologic effects of these earlier events dwarf those of the recent hurricanes. Hurricane Earl's geologic effects at Anegada, observed mainly in 2011, were limited to wrack deposition along many of the island's shores and salt ponds, accretion of small washover (spillover) fans on the south shore, and the suspension and deposition of microbial material from interior salt ponds. Earl's most widespread deposit at Anegada, the microbial detritus, was abundantly juxtaposed with evidence for catastrophic overwash in prior centuries. The microbial detritus formed an extensive coating up to 2 cm thick that extended into breaches in beach-ridge plains of the island's north shore, onto playas that are underlain by a sand-and-shell sheet that extends as much as 1.5 km southward from the north shore, and among southward-strewn limestone boulders pendant to outcrops as much as 1 km inland. Earl's spillover fans also contrast with a sand-and-shell sheet, which was dated previously to 1650–1800, by being limited to the island's south shore and by extending inland a few tens of meters at most. These findings complement those reported in this issue by Michaela Spiske and Robert Halley (Spiske and Halley, 2014), who studied a coral-rubble ridge that lines part of Anegada's north shore. Spiske and Halley attribute the ridge to storms that were larger than Earl. But they contrast the ridge with coral boulders that were scattered hundreds of meters inland by overwash in 1200–1450.

Scenarios of local tsunamis in the China Seas by Boussinesq model

The Okinawa Trench in the East China Sea and the Manila Trench in the South China Sea are considered to be the regions with high risk of potential tsunamis induced by submarine earthquakes. Tsunami waves will impact the southeast coast of China if tsunamis occur in these areas. In this paper, the horizontal two-dimensional Boussinesq model is used to simulate tsunami generation, propagation, and runup in a domain with complex geometrical boundaries. The temporary varying bottom boundary condition is adopted to describe the initial tsunami waves motivated by the submarine faults. The Indian Ocean tsunami is simulated by the numerical model as a validation case. The time series of water elevation and runup on the beach are compared with the measured data from field survey. The agreements indicate that the Boussinesq model can be used to simulate tsunamis and predict the waveform and runup. Then, the hypothetical tsunamis in the Okinawa Trench and the Manila Trench are simulated by the numerical model. The arrival time and maximum wave height near coastal cities are predicted by the model. It turns out that the leading depression N-wave occurs when the tsunami propagates in the continental shelf from the Okinawa Trench. The scenarios of the tsunami in the Manila Trench demonstrate significant effects on the coastal area around the South China Sea.

Análisis de la sismicidad en la costa Pacífica colombiana: herramienta para definir fuentes de tsunami

This research focuses on the study of seismic activity in the Colombian Pacific Coast in order to identify and characterize potential tsunami generating zones, from the application of descriptive and inferential statistics, using the Gutenberg-Richter law for knowing the occurrence of earthquakes according to their magnitude. Identify and characterize the tsunami generating sources is a key component in the evaluation of the hazard, which contributes to reducing the vulnerability of the habitants of the coastal areas, since it is a basic tool for the development of municipal contingency plans for tsunami and allow the National Risk Management Unit to make decisions concerning the management of disasters, training plans in response to tsunami and formulating mitigation strategies [1]. In a temporal space of 100 years, the probability of occurrence of an earthquake of magnitude 7.8 Mw in the Colombian Pacific Coast is 99% with a return period of 15.65 years. This study proposes as tsunami generating sources three potential zones, the zone of interaction between the three plates in proximity to Panama where attend the South American plate, Nazca and Cocos, Yaquina Graben zone, and Colombo-Ecuadorian Subduction Zone.

TSUNAMI HAZARD AND BUILDING DAMAGE ASSESSMENT IN THAILAND USING NUMERICAL MODEL AND FRAGILITY CURVES

Assessing the hazard and damage of a potential tsunami is an ongoing challenge in tsunami research. This study begins by simulating tsunami hazards using historical events. A tsunami propagation model is used to obtain the estimated maximum tsunami height along the west coast of Thailand for a rough return period, and rupture locations that have the potential to generate catastrophic tsunamis in Thailand for a specific return period are proposed. A tsunami inundation model is then performed to quantify each building's maximum inundation depth, using high-resolution satellite images to extract each building's location for the areas of interest located in southern Thailand. Nam Khem village and Patong beach are selected as study areas to represent village communities and tourist attractions, respectively. The model results are then used to obtain the numbers of exposed inhabitants and buildings for each earthquake return period. The developed tsunami fragility curves are applied to these figures to determine the number of potentially damaged buildings. The analysis suggests that the propagation model can be used to obtain rough estimations because it provided results similar to those of the inundation model. However, material type must be considered when fragility curves are used in a different country (i.e. reinforced concrete buildings in Thailand from the 2004 tsunami and wooden houses in Japan from the 2011 East Japan tsunami).