Dynamic Response of Bottom Water Pressure due to the 2011 Tohoku Earthquake
Dynamic Response of Bottom Water Pressure due to the 2011 Tohoku Earthquake
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DOI：
10.20965/jdr.2012.p0468
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发表时间：
2012-08-01
影响因子：
0.8
通讯作者：
Ohmachi, Tatsuo
中科院分区：
文献类型：
--
作者：
Matsumoto, Hiroyuki;Inoue, Shusaku;Ohmachi, Tatsuo
在2011年东北地震（Mw9.0）期间，位于海啸源以北约400公里处的JAMSTEC电缆观测站的两个海底压力计记录了水压变化。在本研究中，观测到的水压波动已被解释的时间-频率处理分析，然后与海底地震仪的波动进行比较。由于地震波的存在，即使在中间场也会产生声共振。本研究表明，在2011年东北地震期间的水压波动的海底加速度和速度的中频范围和高频范围，分别占主导地位，其阈值大致与基本的声学共振频率一致。相比之下，水压振幅与低频范围内的底部振荡无关，其阈值与中间波而不是浅水波有关。
Water pressure changes have been recorded during the 2011 Tohoku earthquake (Mw9.0) by two ocean-bottom pressure gauges of the JAMSTEC cabled observatory located approximately 400 km north of the tsunami source. In the present study, observed water pressure fluctuations have been interpreted by time-frequency processing analysis, followed by a comparison with those fluctuations of ocean-bottom seismometers. Acoustic resonance has been involved due to seismic waves even in the intermediate-field. The present study suggests that water pressure fluctuations during the 2011 Tohoku earthquake are dominated by ocean-bottom acceleration and velocity for the intermediate frequency range and the high-frequency range, respectively, and its threshold roughly coincides with the fundamental acoustic resonant frequency. Water pressure amplitude is independent, in contrast, on bottom oscillations in the low-frequency range, for which the threshold is related to intermediate waves rather than shallow water waves.