Co-seismic geomagnetic fluctuations and atmospheric disturbances during the 2018 M 6.2 Hualien Earthquake

Chun Rong Chen, Jann Yenq Liu, Chieh Hung Chen, Tsung Yu Wu, Horng Yuan Yen, Strong Wen, Bor Shouh Huang, Cheng Horng Lin, Che Min Lin, Hung Hao Hsieh

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The strong ground motion of 6 February 2018 M 6.2 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 s. 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.

Original languageEnglish
Pages (from-to)449-465
Number of pages17
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume30
Issue number3
DOIs
StatePublished - 2019

Keywords

  • Geomagnetic
  • Infrasound
  • Micro-Barometer
  • QuakeFinder
  • Tiltmeter

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