Nimiya Hiro, Ikeda Tatsunori, Tsuji Takeshi
Department of Earth Resources Engineering, Kyushu University, Fukuoka, Japan.
International Institute for Carbon-Neutral Energy Research, Kyushu University, Fukuoka, Japan.
Sci Adv. 2017 Nov 24;3(11):e1700813. doi: 10.1126/sciadv.1700813. eCollection 2017 Nov.
Monitoring of earthquake faults and volcanoes contributes to our understanding of their dynamic mechanisms and to our ability to predict future earthquakes and volcanic activity. We report here on spatial and temporal variations of seismic velocity around the seismogenic fault of the 2016 Kumamoto earthquake [moment magnitude () 7.0] based on ambient seismic noise. Seismic velocity near the rupture faults and Aso volcano decreased during the earthquake. The velocity reduction near the faults may have been due to formation damage, a change in stress state, and an increase in pore pressure. Further, we mapped the post-earthquake fault-healing process. The largest seismic velocity reduction observed at Aso volcano during the earthquake was likely caused by pressurized volcanic fluids, and the large increase in seismic velocity at the volcano's magma body observed ~3 months after the earthquake may have been a response to depressurization caused by the eruption. This study demonstrates the usefulness of continuous monitoring of faults and volcanoes.
对地震断层和火山的监测有助于我们理解它们的动力学机制，并提高我们预测未来地震和火山活动的能力。在此，我们基于背景地震噪声，报告了2016年熊本地震（矩震级7.0）发震断层周围地震波速度的时空变化。地震期间，破裂断层和阿苏火山附近的地震波速度降低。断层附近的速度降低可能是由于地层损伤、应力状态变化和孔隙压力增加所致。此外，我们绘制了地震后断层愈合过程图。地震期间在阿苏火山观测到的最大地震波速度降低可能是由受压的火山流体引起的，而在地震约3个月后在火山岩浆体观测到的地震波速度大幅增加可能是对火山喷发导致的减压的一种响应。这项研究证明了对断层和火山进行连续监测的有用性。
