Aftershock observation of the 2011 off the Pacific coast of Tohoku Earthquake by using ocean bottom seismometer network
Aftershock observation of the 2011 off the Pacific coast of Tohoku Earthquake by using ocean bottom seismometer network
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DOI：
10.5047/eps.2011.05.020
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发表时间：
2011-09
期刊：
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通讯作者：
M. Shinohara;Tomoaki Yamada;K. Nakahigashi;S. Sakai;K. Mochizuki;K. Uehira;Y. Ito;R. Azuma;Y. Kaiho;T. No;H. Shiobara;R. Hino;Y. Murai;H. Yakiwara;Toshinori Sato;Y. Machida;T. Shinbo;T. Isse;H. Miyamachi;K. Obana;N. Takahashi;S. Kodaira;Y. Kaneda;K. Hirata;S. Yoshikawa;K. Obara;T. Iwasaki;N. Hirata
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文献类型：
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作者：
M. Shinohara;Tomoaki Yamada;K. Nakahigashi;S. Sakai;K. Mochizuki;K. Uehira;Y. Ito;R. Azuma;Y. Kaiho;T. No;H. Shiobara;R. Hino;Y. Murai;H. Yakiwara;Toshinori Sato;Y. Machida;T. Shinbo;T. Isse;H. Miyamachi;K. Obana;N. Takahashi;S. Kodaira;Y. Kaneda;K. Hirata;S. Yoshikawa;K. Obara;T. Iwasaki;N. Hirata
2011年3月11日，日本东北部近海发生了2011年东北部太平洋沿岸大地震。为了研究这次地震的余震活动，我们在主震发生四天后开始部署72个海底地震仪（OBSs）。在震源区南部，34个长期OBBS（LT-OBBS）已部署在主震发生前，我们恢复了3个LT-OBBS，以澄清余震的深度分布。使用OBSs的数据，确定了99次余震的位置。大部分余震位于5-30 km的深度范围内，并集中在板块边界区。此外，余震发生在俯冲洋壳和向陆板块的6.2公里/秒层内。在俯冲板块的地幔中没有发现余震。根据以前使用OBS和受控震源进行地震调查的结果，俯冲的菲律宾海板块估计与俯冲的太平洋板块接触。余震活动区的南端对应于两个俯冲板块的接触区。我们推断主震序列的破裂终止于大洋板块接触区。
The 2011 off the Pacific coast of Tohoku Earthquake occurred offshore of northeast Japan region on March 11th, 2011. In order to study the aftershock activity of this event, we started deployment of seventy-two ocean bottom seismometers (OBSs) four days after the mainshock. In the south of the source region, thirty-four longterm OBSs (LT-OBSs) had been deployed before the occurrence of the mainshock, and we recovered three LT-OBSs to clarify the depth distribution of aftershocks. Using the data of OBSs, ninety-nine aftershocks were located. Most of the aftershocks were located in a depth range of 5–30 km and concentrate in the plate boundary region. In addition, aftershocks occurred within the subducting oceanic crust and the 6.2-km/s layer of the landward plate. No aftershocks were found in the mantle of the subducting plate. From the results of a previous seismic survey using OBSs and controlled sources, the subducting Philippine Sea plate is estimated to be in contact with the subducting Pacific plate. The southern end of the seismic activity region of the aftershocks corresponds to the contact region of two subducting plates. We infer that the rupture of the mainshock sequence was terminated at the oceanic plate contact region.