Rapid Moment Tensor Inversion of Earthquakes near Japan for Tsunami Warning: Numerical Experiments
Rapid Moment Tensor Inversion of Earthquakes near Japan for Tsunami Warning: Numerical Experiments
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日本附近地震的快速矩张量反演用于海啸预警：数值实验
DOI：
10.4294/zisin1948.40.3_365
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
I. Nakanishi
中科院分区：
文献类型：
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作者：
Takeshi Fukushima;D. Suetsugu;I. Nakanishi
研究了矩张量反演用于海啸高度快速预报的可能性。在一个假想的宽频带、宽动态范围的数字地震记录台网上进行了反演的数值试验。利用简正波理论，我们反演了震源时间后3分钟的波形。实验结果表明，如果我们能用一个真实的实时在线系统从日本多个台站收集地震资料，就有可能对日本附近的地震进行地震矩和震源机制的快速测定。对于大地震，我们反演方法中的点源假设可能失效。为了估计源的有限性的影响，我们反演计算的移动源的地震图，并发现所获得的标量矩被低估为一半的真正的故障长度为200公里。需要对有限源的反演进行进一步的研究，以实现海啸高度的实际估计。
The possibility of moment tensor inversion for rapid prediction of tsunami height is studied. Numerical experiments of the inversion are made on a hypothetical network of digital seismograms with a very broad band and wide dynamic range. Using the normal mode theory, we invert waveforms with a duration of 3 minutes after the earthquake origin time. The experiments suggest that the rapid determination of seismic moment and source mechanism may be possible for earthquakes near Japan, if we can gather the data by a real time on-line system from several Japanese stations. The assumption of the point source in our inversion method may become invalid for great earthquakes. To estimate the effect of the source finiteness, we invert seismograms calculated for moving sources and find that the obtained scalar moment is underestimated to be half the true one for a fault length of 200 km. Further studies on the inversion for finite sources are required to achieve a practical estimation of tsunami height.