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Tsunami Source of the 2010 Mentawai, Indonesia Earthquake Inferred from Tsunami Field Survey and Waveform Modeling
Satake K.a, Nishimura Y.b, Putra P.S.b,c, Gusman A.R.b, Sunendar H.b, Fujii Y.d, Tanioka Y.b, Latief H.e, Yulianto E.c
a Earthquake Research Institute, University of Tokyo, Japan
b Institute of Seismology and Volcanology, Hokkaido University, Japan
c Research Center for Geotechnology, Indonesian Institute of Science, Indonesia
d International Institute of Seismology and Earthquake Engineering, Building Research Institute, Japan
e Department of Oceanography, Bandung Institute of Technology, Indonesia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]The 2010 Mentawai earthquake (magnitude 7.7) generated a destructive tsunami that caused more than 500 casualties in the Mentawai Islands, west of Sumatra, Indonesia. Seismological analyses indicate that this earthquake was an unusual “tsunami earthquake,” which produces much larger tsunamis than expected from the seismic magnitude. We carried out a field survey to measure tsunami heights and inundation distances, an inversion of tsunami waveforms to estimate the slip distribution on the fault, and inundation modeling to compare the measured and simulated tsunami heights. The measured tsunami heights at eight locations on the west coasts of North and South Pagai Island ranged from 2.5 to 9.3 m, but were mostly in the 4-7 m range. At three villages, the tsunami inundation extended more than 300 m. Interviews of local residents indicated that the earthquake ground shaking was less intense than during previous large earthquakes and did not cause any damage. Inversion of tsunami waveforms recorded at nine coastal tide gauges, a nearby GPS buoy, and a DART station indicated a large slip (maximum 6.1 m) on a shallower part of the fault near the trench axis, a distribution similar to other tsunami earthquakes. The total seismic moment estimated from tsunami waveform inversion was 1.0 × 1021 Nm, which corresponded to Mw 7.9. Computed coastal tsunami heights from this tsunami source model using linear equations are similar to the measured tsunami heights. The inundation heights computed by using detailed bathymetry and topography data and nonlinear equations including inundation were smaller than the measured ones. This may have been partly due to the limited resolution and accuracy of publically available bathymetry and topography data. One-dimensional run-up computations using our surveyed topography profiles showed that the computed heights were roughly similar to the measured ones. © 2012 The Author(s).[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Coastal tide gauges,Indian ocean,Indonesia,Inundation distance,Inundation modeling,Limited resolution,Sumatra , Indonesia,Waveform inversion[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]earthquake,Indian ocean,Indonesia,Mentawai earthquake,Tsunami[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]This survey was made as a part of the SATREPS ‘‘Multi-disciplinary natural hazard reduction from earthquakes and volcanoes in Indonesia’’ project supported by the JST (Japan Science and Technology Agency) and JICA (Japan International Cooperation Agency), as well as RISTEK and LIPI. Among the authors, KS, YN, PSP, HS, and EY conducted the survey. We thank Pariatmono, Mulyo Harris Pradono, Atsushi Koresawa, and Megumi Sugimoto, who also joined the survey to study the reactions of residents. We thank Jody Bourgeois for reading and commenting on the results of the field survey. The tsunami waveform analysis and simulations were conducted by KS, ARG, HS, TF, HL, and YT. In particular, YF took the lead in tsunami waveform inversion, HS in detailed simulation, and ARG in one-dimensional computation. We respect and appreciate the efforts of the operators of the costal tide gauge stations, DART and GPS buoy stations. The buoy data were provided to us by Wahyu Pandoe of BPPT and Tilo Schoene at GFZ. We also thank Jose Borrero, two anonymous reviewers, and Herman Fritz for their comments on the final manuscript.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1007/s00024-012-0536-y[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]