Significant tsunami observed at ocean-bottom pressure gauges during the 2011 off the Pacific coast of Tohoku Earthquake
Significant tsunami observed at ocean-bottom pressure gauges during the 2011 off the Pacific coast of Tohoku Earthquake
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DOI：
10.5047/eps.2011.06.005
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发表时间：
2011-01-01
影响因子：
3
通讯作者：
Shinohara, Masanao
中科院分区：
文献类型：
--
作者：
Maeda, Takuto;Furumura, Takashi;Shinohara, Masanao
2011年东北大地震造成了一场毁灭性的海啸，沿着从东北到关东地区的海岸线。虽然东北沿海沿着的许多验潮站都因海啸而饱和或受损，但在釜石附近安装的两个海底电缆海啸传感器成功记录了震源破裂区上方的海啸波形。记录表明，一个典型的两阶段的海啸发展序列：一个平稳增加的海啸振幅从0到2米，在第一个800 s的地震起源时间，和一个短周期的脉冲海啸的峰值超过5米，在随后的200 s。这些观测结果强烈表明，地震期间各观测站没有发生任何海底隆起，而太平洋板块俯冲带的浅部在海沟轴线附近发生了极大的滑动。根据近海海啸记录得出的震源模型表明，1896年明治三陆海啸地震破裂区以南，宫城附近海沟轴线处发生了57 m的巨大滑移，这是随后发生的高破坏性海啸的主要震源。
The 2011 Tohoku Earthquake caused a devastating tsunami along the shoreline from the Tohoku to Kanto districts. Although many of the tide gauge stations along the Tohoku coast were saturated or damaged due to the tsunami, two cabled ocean-bottom tsunami sensors installed off Kamaishi successfully recorded the tsunami waveform just above the source rupture area. The records indicated a characteristic two-stage tsunami development sequence: a smoothly increasing tsunami amplitude from 0 to 2 m during the first 800 s from the earthquake origin time, and a short-period impulsive tsunami with a peak of more than 5 m in the following 200 s. Such observations strongly suggest the lack of any sea floor upheaval at the stations during the earthquake, and the occurrence of an extremely large slip in the shallow portion of the subducting Pacific Plate near the trench axis. The source model derived from the offshore tsunami records indicates that a very large slip of 57 m occurred off Miyagi near the trench axis, south of the rupture area of the 1896 Meiji Sanriku tsunami earthquake, and was the major source of the highly destructive tsunami that subsequently developed.