Remote triggering of seismicity at Japanese volcanoes following the 2016 M7.3 Kumamoto earthquake
Remote triggering of seismicity at Japanese volcanoes following the 2016 M7.3 Kumamoto earthquake
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DOI：
10.1186/s40623-016-0539-5
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发表时间：
2016-10-20
影响因子：
3
通讯作者：
Yagi, Yuji
中科院分区：
文献类型：
--
作者：
Enescu, Bogdan;Shimojo, Kengo;Yagi, Yuji
2016年4月16日，九州西部发生M(JMA)7.3熊本地震，震源深度12公里，位于活动走滑断层上。在这里，我们通过分析日本各地地震台记录的连续波形数据，报告了远至北海道的相对广泛的远程小地震活动。日本以前从未报道过在内陆大地震后发生的这种相对广泛的远程地震活动。我们的分析表明，远程事件是由熊本地震的表面波通过而动态触发的。东北和北海道地区以及伊豆半岛附近的大多数远程触发事件都发生在火山或火山附近，这表明瑞利波通过对地壳流体的激发发挥了重要的触发作用。然而，其他地区（如能登半岛）的远程激活发生在远离火山的地方。熊本地震期间震源方向性效应增强了振幅相对较大的拉夫波，可能引发了当地活动断层的地震活动。观测到远程触发区域的动态应力范围为几kPa到几十kPa，阈值低于日本以往的动态触发案例；这可能与 2011 年 M9.0 东北冲地震后地壳条件的变化有关，特别是日本东北部的火山。
The M(JMA)7.3 Kumamoto earthquake occurred on April 16, 2016, in the western part of Kyushu, at a depth of 12 km, on an active strike-slip fault. Here, we report on a relatively widespread activation of small remote earthquakes, which occurred as far as Hokkaido, detected by analyzing the continuous waveform data recorded at seismic stations all over Japan. Such relatively widespread remote seismicity activation, following a large inland earthquake, has not been reported before for Japan. Our analysis demonstrates that the remote events were triggered dynamically, by the passage of the surface waves from the Kumamoto earthquake. Most of the remotely triggered events in the Tohoku and Hokkaido regions, as well as close to Izu Peninsula, occur at or close to volcanoes, which suggests that the excitation of crustal fluids, by the passage of Rayleigh waves, played an important triggering role. Nevertheless, remote activation in other regions, like Noto Peninsula, occurred away from volcanoes. The relatively large-amplitude Love waves, enhanced by a source directivity effect during the Kumamoto earthquake, may have triggered seismicity on local active faults. The dynamic stresses in the areas where remote activation has been observed range from several kPa to tens of kPa, the thresholds being lower than in previous dynamic triggering cases for Japan; this might relate to a change in the crustal conditions following the 2011 M9.0 Tohoku-oki earthquake, in particular at volcanoes in NE Japan.