Tsunami source of the 2011 off the Pacific coast of Tohoku Earthquake
Tsunami source of the 2011 off the Pacific coast of Tohoku Earthquake
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DOI：
10.5047/eps.2011.06.010
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发表时间：
2011-01-01
影响因子：
3
通讯作者：
Kanazawa, Toshihiko
中科院分区：
文献类型：
--
作者：
Fujii, Yushiro;Satake, Kenji;Kanazawa, Toshihiko
对2011年3月11日日本东北部太平洋沿岸地震（M9.0）的海啸波形反演结果表明，最大海啸的震源位于日本海沟轴线附近。海底压力和GPS波仪记录了两步海啸波形：海平面逐渐上升（约2米），随后是脉冲海啸波（3至5米）。根据33个海岸验潮站、近海GPS测波站和海底压力站的观测资料，计算出的滑移量分布表明，滑移量最大的区域位于沿着槽轴方向，最大滑移量超过40 m。这种离岸滑动，类似但比1896年三陆“海啸地震”大得多，是记录到的大脉冲峰值的原因。在地震中心附近的三陆冲南部（类似于30米）和宫城冲（类似于17米）的板块界面上的大滑动，比869年常根地震的先前提出的断层模型具有更大的滑动，这是最初的水位上升的原因，据推测，仙台平原的大海啸淹没。板间滑动在福岛冲木地区接近10 m，在茨城冲木地区小于3 m。总地震矩估计为3.8 × 10（22）N-m（M-w = 9.0）。
Tsunami waveform inversion for the 11 March, 2011, off the Pacific coast of Tohoku Earthquake (M 9.0) indicates that the source of the largest tsunami was located near the axis of the Japan trench. Ocean-bottom pressure, and GPS wave, gauges recorded two-step tsunami waveforms: a gradual increase of sea level (similar to 2 m) followed by an impulsive tsunami wave (3 to 5 m). The slip distribution estimated from 33 coastal tide gauges, offshore GPS wave gauges and bottom-pressure gauges show that the large slip, more than 40 m, was located along the trench axis. This offshore slip, similar but much larger than the 1896 Sanriku "tsunami earthquake," is responsible for the recorded large impulsive peak. Large slip on the plate interface at southern Sanriku-oki (similar to 30 m) and Miyagi-oki (similar to 17 m) around the epicenter, a similar location with larger slip than the previously proposed fault model of the 869 Jogan earthquake, is responsible for the initial water-level rise and, presumably, the large tsunami inundation in Sendai plain. The interplate slip is similar to 10 m in Fukushima-oki, and less than 3 m in the Ibaraki-oki region. The total seismic moment is estimated as 3.8 x 10(22) N-m (M-w = 9.0).