To evaluate the differences of tsunami simulation results between excluding and including the uncertainty of the scaling relationships, 150 points are selected to record the maximum tsunami wave height along the coastal line of Padang starting from Tabing to Teluk Bayur (see Figure 10A). results are also consistent, i.e., 20–25 min after the event. U.S.A. 103, 19673–19677. For instance, the maximum height from the 90th percentile of the second and third waves for the Mw 9.0 scenario without considering the uncertainty is ~5 m, while it is ~7.5 m for the case considering the uncertainty of the scaling relationships. Figure 4. The width, length, strike, and dip angles define the geometry of the fault plane, while the mean slip, maximum slip, and Box–Cox parameter characterize the slip statistics values. Res. Hazard maps created by the Indonesian Agency for Meteorology, Climatology and Geophysics, known as BMKG (Badan Meteorologi, Klimatologi, dan Geofisika), show that earthquakes and tsunamis are particularly frequent on those islands directly adjacent to the boundaries of the tectonic plates that meet in Indonesia’s midst — specifically the Indo-Australian, Pacific, Philippine Sea and Sunda plates — which are continuously moving and straining against one another. doi:10.1785/0120050609, Borrero, J. C., Sieh, K., Chlieh, M., and Synolakis, C. E. (2006). The use of the linear interpolation scheme is deemed as appropriate over other more complex schemes, such as spline interpolation, because at the near coastal line areas (where drastic changes of the spatial density of the data points are inevitable), complex interpolation methods may over-interpolate the topographical features. The historic earthquake record of the Sunda–Andaman subduction zone suggests that the potential for great destructive subduction zone megathrust earthquakes is much larger for Sumatra than Java . The verified scaling relationships are further used to generate the earthquake source models for tsunami simulation. The results shown in Figure 4 indicate that the estimated source parameters are in agreement with the scaling relationships; for most cases, the estimated parameters fall within the 16th to 84th percentile confidence interval of the prediction equations. doi:10.1142/S1793431110000790, Nalbant, S. S., Steacy, S., Sieh, K., Natawidjaja, D., and McCloskey, J. (C) Mw 8.75 scenario without considering uncertainty. “We now tell our people that if the earthquake happens [and is] bigger than magnitude 7 … the authorities will make an announcement about a tsunami potential. doi:10.1126/science.1163589, Sladen, A. The 220-km long rupture extension from the southern part of the uplift was defined as the south-eastern boundary of the 1833 fault rupture. “GPS provides what is happening before an earthquake occurs — how the surface is deforming, and how the slip is occurring [on a fault] — and what happens after a quake.”. In recent years, the Indonesian government, along with other groups like the Earth Observatory of Singapore and the U.S. Pacific Tsunami Warning Center, has been introducing technologies to improve hazard forecasting, warning and mitigation. the results show that for the future major earthquakes in the Sunda megathrust, the maximum tsunami wave height in Padang areas can reach 20 m and, therefore, signifi-cant damage and loss may be anticipated in this region. These values are comparable to the slab models for the Sunda subduction zone produced by the USGS (Hayes et al., 2009, 2012). Therefore, it can be concluded that the tsunami risk potential in Padang is high due to the future tsunamigenic event from the Mentawai segment of the Sunda subduction zone. The simulated tsunami wave profiles from the Mw 9.0 scenario were compared with the results from Muhari et al. A 1,000-year sediment record of tsunami recurrence in northern Sumatra. Seismic history and seismotectonics of the Sunda arc. The past seismicity in the Mentawai segment indicates that the most destructive historical event in this segment occurred in 1833. Before running the stochastic tsunami simulation, earthquake scenarios (e.g., magnitude and source zone) need to be selected and a suitable fault rupture zone model (e.g., geometry and asperity zone) needs to be defined. A recent significant earthquake occurred in the Mentawai segment was the Mw 8.4 12 September 2007 Bengkulu earthquake. Therefore, the potential for large tsunamigenic events in the Mentawai segment remains high (Konca et al., 2008). “We are trying to develop and integrate local wisdom with technology, so that communities can build the capacity to cope with the disaster themselves,” he says. Special Publications, 441. A paleotsunami study based on a 1,000-year long record of tsunami deposits in North-West of Sumatra suggests that the occurrence interval of tsunamigenic earthquakes (Mw 9.15) from the Sumatra-Andaman region is about 600 years (Monecke et al., 2008). The authors are grateful to Abdul Muhari, Hilman Natawidjaja, and Widjo Kongko who provide an earthquake source model for the future tsunamigenic event in the Mentawai segment and the bathymetry and elevation data for Padang. J. Geophys. Preliminary Result of the Feb 20, 2008 Mw 7.4 Simeulue Earthquake. These include fault boundary rupture, deformation of overlying plate, splay faults and landslides. For each tsunami simulation run, tsunami waveforms are recorded at three points with the water depth of 5 m: Tabing (0.85°S and 100.34°E), Purus (0.88°S and 100.345°E), and Teluk Bayur (1°S and 100.38°E) as shown in Figure 9A. Tsunami wave profiles at the Tabing station (P1). 6, 19–38. The seismological knowledge of earthquake rupture in the target region must be reflected in the asperity zone. And, by virtue of the archipelago’s equatorial location and its array of physiographically diverse islands, different parts of the country are subjected to a wide variety of weather, from drenching monsoon rains to prolonged dry spells. The earthquake was felt as far away as the Malay peninsula and the eastern part of Java. Griffin, J. D., Pranantyo, I. R., Kongko, W., Haunan, A., Robiana, R., Miller, V., et al. (2008) considered the uncertainty of slip distribution by implementing the heterogeneous spatial distribution of slips based on a methodology proposed by Mai and Beroza (2002) and produced more than 100 scenarios to assess the tsunami hazards along the western coast of Sumatra. It’s a gap that could be hazardous. Twelve hours later, a subsequent fault rupture produced another major earthquake of Mw 7.9. In order to generate the earthquake source parameters, the fault length (L), fault width (W), mean slip (Da), maximum slip (Dm), Box–Cox parameter (λ), correlation length along strike direction (Ax), correlation length along dip direction (Az), and Hurst number (H) of 19 finite-fault models of the past Sunda subduction earthquakes are calculated. (2016). In stochastic source modeling, slip values that are consistent with considered spatial slip distribution features are generated. (A) Mw 8.5 scenario without considering uncertainty. Res. The 2007 earthquake initiated 750 km south of the … (2008). Figure 5. The circular average of the normalized wavenumber spectra is calculated, and the fractal dimension Df is defined based on the least squares fitting. But Dewi still worries that hundreds of thousands of people won’t escape low-lying areas in time if a tsunami comes quickly and washes out key bridges and other infrastructure. On the other hand, McCloskey et al. A large earthquake in 2007 (Mw 8.4) that ruptured the Sunda megathrust near the 1833 rupture area was significantly smaller than the accumulated slip since the twin events of the 1797 and 1833 earthquakes (McCloskey et al., 2005; Nalbant et al., 2005). The effects of surface roughness on tsunami flows are modeled through the Manning’s bottom friction formula with a uniform roughness coefficient of 0.025 m−1/3s. (2006). Preliminary Result of the Sep 12, 2007 Mw 7.9 Kepulauan Earthquake. IOC Manual. Seismol. The 1861 Sumatra earthquake occurred on February 16 and was the last in a sequences of earthquakes that ruptured adjacent parts of the Sumatran segment of the Sunda megathrust. Earthquake hazard in the Sunda trench. The tsunami simulation results including the simulated tsunami wave height profiles and maximum tsunami heights along the coastal line are presented in this section by considering three magnitude scenarios (Mw 8.5, 8.75, and 9.0) and two cases ignoring and incorporating the uncertainty of the scaling relationships. Tsunami wave profiles at the Teluk Bayur station (P3). Lett. The raw simulated data are shown with gray color and the median and 10th/90th percentiles of the simulated tsunami waveforms are illustrated with red line and blue line, respectively. “But in September 2007, we had a magnitude-7-plus earthquake, and the government woke up and started trusting our organization.”. Sensitivity of tsunami wave profiles and inundation simulations to earthquake slip and fault geometry for the 2011 Tohoku earthquake. The earthquake source parameters from the finite-fault models of the past Sunda subduction earthquakes are first calculated and then compared with the global scaling relationships developed by Goda et al. source model. In 2017, Indonesians reported 787 floods, 716 tornadoes, 614 landslides, and 96 forest and ground fires (burning peat lands and rainforests to make room for large palm oil plantations and smaller farms is a popular practice, especially in Sumatra). Acad. With the plain topographic features and high population density in urban areas, Padang will face significant economic and social losses due to the future tsunamigenic event in the Mentawai segment of the Sunda subduction zone. Although seismologists and disaster mitigation authorities in the country have hoped to procure new technology to more quickly detect incipient threats, an array of nontechnical factors impedes progress. Indonesia is a country with 55,000 kilometers of coastline and more than 266 million inhabitants living on 6,000 islands, many of which are among the most remote in the world, where cellphone and internet coverage is rare. These buoys and sensors can be linked with GPS systems to better measure seafloor displacement and detect tsunamis, but the InaTEWS system is not integrated at all with GPS networks configured for hazard warnings or for measurements of plate movement. Using the stochastic tsunami simulation results for the Mw 9.0 scenario, sensitivity analysis of the tsunami simulated wave profiles is carried out and presented in this section. The oceanic and continental plates along the Sunda Megathrust Fault separated in 2004, causing a huge earthquake. Click here for all copyright requests. J. Geophys. The south-eastern limit of the rupture was at about 3.2°S since the south-eastern limit of the uplift due to the 1797 event was on South Pagai Island. “Because of the technical changes in volcanic science, we have had fewer victims in the past 20 years,” says Devy Kamil Syahbana, a field specialist with the Indonesian Center for Volcanology and Geological Hazard Mitigation (Pusat Vulkanologi dan Mitigasi Bencana Geologi Badan) who monitors Mount Agung on Bali. Around the Pacific Ocean is a horseshoe shaped area that contains subduction zones that create megathrust earthquakes and generate tsunamis. Indonesians also reported 19 regional droughts, two volcanic eruptions — at Mount Sinabung on Sumatra and Mount Agung on Bali — and 11 tsunamis. J. Geophys. “The best thing is to have one integrated warning system in the Indian Ocean … one that is as close as possible to earthquake sources.” As president of the Asian Seismological Commission, Banerjee is organizing a conference in China to try to create that network out of the patchwork of systems that exist today. “You can’t predict earthquakes, and that hasn’t changed.”. The 1861 Sumatra earthquake occurred on February 16 and was the last in a sequences of earthquakes that ruptured adjacent parts of the Sumatran segment of the Sunda megathrust. Res. (2014). Tsunami wave propagation is then evaluated by solving non-linear shallow water equations with run-up (Goto et al., 1997). SRCMOD: an online database of finite source rupture models. doi:10.1029/96GL00736, United States Geological Survey (USGS). It caused a devastating tsunami which led to several thousand fatalities. Sumatra. Moreover, those previous investigations for the Mentawai-Sunda subduction zone adopted the global empirical scaling relationships [e.g., Mai and Beroza (2002), Gallovič and Brokešová (2004), and Aydan (2008)] to generate only either deterministic fault geometry parameters (width and length) or slip distribution parameters without considering the uncertainty and relationships among earthquake source parameters. Seismol. Sumatra Island is the most seismically active region since it is located at the interface between the Indian-Australian and Eurasian Plates. Conflicting agendas among multiple disaster agencies sometimes get in the way, as do limited funding for disaster monitoring and response, which influences both technology choices and civic responses. Therefore, it is important to apply the stochastic tsunami simulation method to assess the tsunami hazard in Padang probabilistically due to the future megathrust earthquakes in the Mentawai segment of the Sunda subduction zone. 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