INVERSION OF TSUNAMI WAVEFORMS FOR THE ESTIMATION OF HETEROGENEOUS FAULT MOTION OF LARGE SUBMARINE EARTHQUAKES - THE 1968 TOKACHI-OKI AND 1983 JAPAN SEA EARTHQUAKES
INVERSION OF TSUNAMI WAVEFORMS FOR THE ESTIMATION OF HETEROGENEOUS FAULT MOTION OF LARGE SUBMARINE EARTHQUAKES - THE 1968 TOKACHI-OKI AND 1983 JAPAN SEA EARTHQUAKES
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DOI：
10.1029/jb094ib05p05627
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发表时间：
1989-05-10
期刊：
影响因子：
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通讯作者：
SATAKE, K
中科院分区：
文献类型：
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作者：
SATAKE, K
海啸资料的波形反演提供了独立可靠的震源过程信息。海啸的传播效果占计算绿色的功能，使用有限差分法和使用已知的水深，这是更好地约束比地震速度结构。观测到的海啸波形的验潮系统的响应，通过使用现场测量的结果进行了校正。使用绿色函数计算水深数据在2.5公里的网格和观察到的波形数字化在1分钟的时间间隔，断层不均匀性的空间分辨率由本方法是小到30公里。该方法被应用于1968年十胜冲地震和1983年日本海地震。1968年地震的滑动主要集中在断层面的西北部。对于1983年的地震，震中以北的断层的滑动是其他部分的两倍。这些凹凸分布与地震波分析推断的凹凸分布相似。然而，恢复的总地震矩较小。本方法被证明是一个有用的技术，估计非均质断层运动，特别是历史事件没有或不良的地震记录，海啸地震中的地震和海啸波的激发是不同的。
Waveform inversion of tsunami data provides independent and reliable information on earthquake source processes. The propagation effects of tsunamis are accounted for by computing Green's functions using a finite difference method and using the known bathymetry, which is much better constrained than the seismic velocity structure. The observed tsunami waveforms are corrected for the response of the tide gage system by using the results of in situ measurements. Using Green's functions computed from bathymetric data on a 2.5‐km grid and the observed waveforms digitized at 1‐min intervals, the spatial resolution of the faulting heterogeneity by the present method is as small as 30 km. This method is applied to the 1968 Tokachi‐oki and 1983 Japan Sea earthquakes. The slip is concentrated at the northwestern part of the fault plane for the 1968 event. For the 1983 event the slip on the fault just north of the epicenter is twice that of the other parts. These asperity distributions are similar to those inferred from seismic wave analysis. However, the recovered total seismic moments are smaller. The present method is shown to be a useful technique for estimating heterogeneous fault motion, especially for historical events with no or poor seismic records, and tsunami earthquakes in which the excitations of seismic and tsunami waves are different.