Depth distribution of coseismic slip along the Nankai Trough, Japan, from joint inversion of geodetic and tsunami data
Depth distribution of coseismic slip along the Nankai Trough, Japan, from joint inversion of geodetic and tsunami data
复制标题
大地测量和海啸数据联合反演日本南海海槽同震滑动的深度分布
DOI：
10.1029/92jb01553
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发表时间：
1993
影响因子：
--
通讯作者：
K. Satake
中科院分区：
文献类型：
--
作者：
K. Satake
通过对大地测量和海啸资料的联合反演，可以估算出与大俯冲地震有关的断面上同震滑动分布，特别是与大俯冲地震有关的下倾方向同震滑动分布。1944年的Tonankai地震（Mw=8.1）和1946年的Nankaido地震（Mw=8.3）两次大地震发生在日本西南部的南开海槽，菲律宾海板块在这里俯冲到欧亚板块之下。这些事件的源头延伸到陆地和海洋。陆地上的同震地壳运动是用水准测量的，而海洋中的同震地壳运动是用潮汐计记录的海啸波形。从这些数据反演的同震滑动分布表明，断平面较浅部分的滑动与较深部分的滑动相当。这表明在当前地震活动性较低的增生楔下可能发生较大的同震滑动。这一结果对具有类似构造环境的其他俯冲带（如美国太平洋西北地区）具有启示意义。尽管该地区发生大地震的可能性仍有争议，但如果该地区发生大的俯冲地震，浅部的同震滑动可能很大，发生大海啸的可能性很高。
Coseismic slip distribution on the fault plane, particularly in the downdip direction, associated with large subduction earthquakes can be estimated by joint inversion of geodetic and tsunami data. Two large earthquakes, the 1944 Tonankai earthquake (Mw=8.1) and the 1946 Nankaido earthquake (Mw=8.3), occurred on the Nankai trough, southwestern Japan, where the Philippine Sea plate is subducting beneath the Eurasian plate. The source areas of these events extended over both land and ocean. Coseismic crustal movements on land were measured by leveling, while those in ocean were recorded as tsunami waveforms on tide gauges. The coseismic slip distribution inverted from these data shows that the slip on the shallower part of the fault plane is comparable to that on the deeper parts. This indicates that large coseismic slip can occur beneath an accretionary wedge where current seismicity is low. The result has implications for other subduction zones having a similar tectonic environment such as for the Pacific Northwest region of the United States. Although the possibility of a large earthquake there is still debated, should a large subduction earthquake occur in this region, coseismic slip on the shallow part could be large, and the potential for large tsunamis is high.