Coseismic slip distribution of the 1946 Nankai earthquake and aseismic slips caused by the earthquake
Coseismic slip distribution of the 1946 Nankai earthquake and aseismic slips caused by the earthquake
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1946年南开地震同震滑移分布及地震引起的抗震滑移
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
K. Satake
中科院分区：
文献类型：
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作者：
Y. Tanioka;K. Satake
根据海啸波形反演结果，估算了1946年南海地震（Mw8.3）断层面上的同震滑动分布。对以前的研究（Satake，1993）进行了以下三项改进。(1)使用更多数量的较小的子断层;（2）子断层更好地拟合板状几何形状;（3）使用更详细的测深数据。反演结果表明，观测波形与合成波形的一致性较以往研究有很大提高。在四国外海震源区的西半部，在锁定带的下倾端附近发生了约6 m的大滑移。上倾或浅部的滑动量很小，表明该区地震耦合较弱。在纪伊半岛外震源区的东半部，约3米的大滑动延伸到整个锁定区。根据大地测量数据（Sagiya和撒切尔，1999年）估计的上板块扇断层上的大滑动不需要解释海啸波形，这表明大滑动是无震的。两个板块界面的下倾端的滑动分布，一个来自大地测量数据，另一个来自海啸波形，除了四国的室户角下的滑动外，都吻合得很好。这表明在室户角下面的板块界面上也发生了地震滑动。
Coseismic slip distribution on the fault plane of the 1946 Nankai earthquake (Mw 8.3) was estimated from inversion of tsunami waveforms. The following three improvements from the previous study (Satake, 1993) were made. (1) Larger number of smaller subfaults is used; (2) the subfaults fit better to the slab geometry; and (3) more detailed bathymetry data are used. The inversion result shows that the agreement between observed and synthetic waveforms is greatly improved from the previous study. In the western half of the source region off Shikoku, a large slip of about 6 m occurred near the down-dip end of the locked zone. The slip on the up-dip or shallow part was very small, indicating a weak seismic coupling in that region. In the eastern half of the source region off Kii peninsula, a large slip of about 3 m extended over the entire locked zone. Large slips on the splay faults in the upper plate estimated from geodetic data (Sagiya and Thatcher, 1999) were not required to explain the tsunami waveforms, suggesting that the large slips were aseismic. Two slip distributions on the down-dip end of the plate interface, one from geodetic data and the other from tsunami waveforms, agree well except for slip beneath Cape Muroto in Shikoku. This suggests that aseismic slip also occurred on the plate interface beneath Cape Muroto.