Spatial distribution of earthquakes off Sanriku, northeastern Japan, in 1989 determined by ocean-bottom and land-based observation
Spatial distribution of earthquakes off Sanriku, northeastern Japan, in 1989 determined by ocean-bottom and land-based observation
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1989年日本东北部三陆海域地震的空间分布，由海底和陆地观测确定
DOI：
10.4294/jpe1952.38.347
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
T. Iwasaki
中科院分区：
文献类型：
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作者：
A. Nishizawa;T. Kono;A. Hasegawa;Tomowo Hirasawa;T. Kanazawa;T. Iwasaki
1989年10月~ 11月，日本东北三陆近海相继发生了5次M≥6级地震，其中包括1次7.1级地震，使该地区的地震活动变得异常活跃。由于地震活动区远离陆地观测网，很难获得准确的震源位置。为了准确定位震源，研究震源活动特征，我们进行了海底地震观测。结合OBS和陆地台站资料进行震源定位，得到两个主要结论。(1)本次活动的震中几乎都是从4km等深线向陆分布。观测到一些地震群，包括一次5.6级地震及其余震。(2)震源深度小于20公里，地震活动被解释为发生在俯冲太平洋板块和向陆板块之间的边界附近。考虑到这一活跃期较大地震的机制，这一活动是一个逆冲断层类型，而不是1933年的三陆地震，这是一个正常的断层类型，可能会打破整个海洋岩石圈。
In October-November, 1989, five M≥6 earthquakes, including an M7.1 earthquake, sequentially took place off Sanriku, northeastern Japan, and the earthquake activity became very high in this region. Since the seismically active zone was far from the land observation network, it was difficult to obtain accurate hypocenter locations. We carried out ocean bottom seismographic observation in order to locate the hypocenters precisely and investigate characteristics of the activity. Combining the OBS and land station data for hypocenter determination, we obtained two main conclusions. (1) Almost all epicenters of the present activity distribute landward from the 4 km isobath. Some earthquake clusters were observed including an M5.6 earthquake and its aftershocks. (2) Focal depths of the earthquakes are shallower than 20 km and the activity is interpreted to take place around the boundary between the subducting Pacific plate and the landward plate. Taking account of the mechanisms of the larger earthquakes in this active period, this activity is a thrust fault type and is different from the 1933 Sanriku earthquake which was a normal fault type and might have broken the entire oceanic lithosphere.
根据验潮仪数据推断 1960 年智利地震的海啸来源
DOI：
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发表时间：
2010
期刊：
影响因子：
--
作者：
Nguyen-T.;H. A.;Matsumoto;J.;and Endo;N.;Yushiro Fujii
通讯作者：
Yushiro Fujii