日本京都大学Bogdan Enescu副教授学术报告会

地球系统科学论坛第548期：Bogdan Enescu副教授学术报告会

   应bwin必赢电子唯一官网王墩教授邀请，日本京都大学Bogdan Enescu副教授来校访问并做学术报告。

   报告时间：2017年9月21日（周四）上午10:00-11:30

   报告地点：主楼412

   报告题目：Remote triggering of earthquakes as a possible stress-meter: the case of the 2016 M7.3 Kumamoto (Japan) mainshock

  报告人简介：Bogdan Enescu博士2004年毕业于日本京都大学理学院地球物理专业。随后在日本防灾科学技术研究所、筑波大学、京都大学工作。主要研究兴趣为地震活动的时空分布及地震灾害研究、触发地震和慢地震、地震高精度定位、同震和震后位移等方向。在国际主流学术刊物发表论文61篇，引用1400余次，H-index为24。

   报告内容简介：

  Activation of seismicity at remote locations due to the passage of seismic waves from large earthquakes is well-documented.  However, distant earthquake triggering is scarce in Japan, with the notable exception of the remote seismicity activated by the 2011 M9.0 Tohoku-oki earthquake. Here we report on a relatively widespread remote triggering of small events following the 2016 M7.3 Kumamoto earthquake and hypothesize on its causes. To perform the analysis, we have processed waveform data recorded by high-sensitivity Hi-net and broadband F-net stations, operated by NIED, as well as JMA stations all over Japan.

  Our results indicate that the activated seismicity correlates well with the passage of surface waves from the Kumamoto earthquake. The furthest triggered event was observed at Akan volcano (Hokkaido) at ~1630 km epicentral distance. Triggering has been also observed at other volcanoes in Tohoku, Chubu and around Izu Peninsula. Some active fault areas like Tottori and Noto Peninsula were also activated. The dynamic stresses at the triggered locations range from several to tens of kPa. Since most of the remotely triggered earthquakes were observed at volcanoes, the excitation of crustal fluids was likely the main triggering mechanism.

  We found that the regions activated this time, in particular some volcanic areas in Tohoku, have been also activated after the 2011 Tohoku-oki earthquake. We hypothesize that mechanical weakening of a pressurized crust in these regions due to the 2011 megathrust might be responsible for an increased trigger-ability. In addition, the activation of some active crustal faults might be related to the levels of tectonic stress along these fault lines. These observations suggest that remote triggering might be used as a stress-meter at volcanoes and active faults.

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2017年9月