Japan Geoscience Union Meeting 2019

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[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS04] Interdisciplinary studies on pre-earthquake processes

Thu. May 30, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Katsumi Hattori(Department of Earth Sciences, Graduate School of Science, Chiba University), JANN-YENQ Liu(Institute of Space Science, National Central University, Taiwan), Dimitar Ouzounov(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA), Qinghua Huang(Peking University)

[MIS04-P05] Co-seismic geomagnetic fluctuations and atmospheric disturbances during the 2018 M6.2 Hualien Earthquake

*Chun-Rong Chen1, JANN-YENQ Liu1 (1.Graduate Institute of Space Science, National Central University)

Keywords:Geomagnetic, QuakeFinder, Infrasound, micro-Barometer, Tiltmeter

The strong ground motion of 6 February 2018 M6.2 Hualien Earthquake triggered a series of co-seismic geomagnetic fluctuations and seismo-traveling atmospheric disturbances (STADs) signatures in infrasonic waves and micro-pressures upon the seismic wave arrival. Networks of 9 QuakeFinder systems, 3 infrasound systems, 2 tiltmeters, 2 micro-barometers, and 11 co-located seismometers are used in this study. Each QuakeFinder system consists of a 3-axes induction magnetometer, an air conductivity sensor, a geophone, and temperature/relative humidity sensors. Co-seismic signatures clearly appear in the induction magnetometers, infrasound systems, and micro-barometers data. The magnetometers register both high- and low-frequency pulsations. Geomagnetic fluctuations occur upon the seismic wave arrival but last a longer duration, while the STADs lag their co-located seismic waves by about 15-45 seconds. The long-lasting fluctuations recorded by both induction and fluxgate magnetometers suggest that the ground/underground water motion play an important role, which is further conformed by low-frequency fluctuations in the tiltmeter data. In general, the amplitude of geomagnetic fluctuations decays as away from the epicenter. However, unusual large co-seismic geomagnetic fluctuations are detected over areas of the abnormal seismic intensity level and/or the magnetic underground structure with anomalously high susceptibilities.