Tsunami Source of the 2010 Mentawai, Indonesia Earthquake Inferred from Tsunami Field Survey and Waveform Modeling
Tsunami Source of the 2010 Mentawai, Indonesia Earthquake Inferred from Tsunami Field Survey and Waveform Modeling
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DOI：
10.1007/s00024-012-0536-y
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发表时间：
2013-09
影响因子：
2
通讯作者：
K. Satake;Y. Nishimura;P. Putra;A. Gusman;Haris Sunendar;Y. Fujii;Y. Tanioka;H. Latief;E. Yulianto
中科院分区：
文献类型：
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作者：
K. Satake;Y. Nishimura;P. Putra;A. Gusman;Haris Sunendar;Y. Fujii;Y. Tanioka;H. Latief;E. Yulianto
2010年明打威地震（7.7级）引发了一场毁灭性的海啸，在印度尼西亚苏门答腊以西的明打威群岛造成500多人伤亡。地震学分析表明，这次地震是一次不寻常的“海啸地震”，它产生的海啸比地震震级预期的要大得多。我们进行了实地调查，以测量海啸的高度和淹没距离，海啸波形的反演，以估计断层上的滑动分布，和淹没建模，比较测量和模拟的海啸高度。在北帕盖岛和南帕盖岛西海岸的8个地点测得的海啸高度从2.5米到9.3米不等，但大多数在4米到7米之间。在三个村庄，海啸淹没范围超过300米。对当地居民的采访表明，这次地震的地面震动不如以往的大地震强烈，没有造成任何损害。在9个沿海验潮仪、附近的GPS浮标和DART站记录的海啸波形反演表明，在海沟轴附近的断层较浅部分有一个大的滑动（最大6.1米），这种分布与其他海啸地震相似。由海啸波形反演得到的总地震矩为1.0 × 1021Nm，相当于Mw7.9。从这个海啸源模型使用线性方程计算的沿海海啸高度与测量的海啸高度相似。利用详细的地形、水深资料和包含淹没量的非线性方程计算的淹没高度小于实测淹没高度。这可能部分是由于海上现有的测深和地形数据分辨率和准确度有限。一维助跑计算使用我们的地形剖面测量表明，计算的高度大致相似的测量。
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 × 1021Nm, which corresponded to Mw7.9. 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.