Natural Hazards Research (Mar 2022)
The electromagnetic anomalies recorded by CSES during Yangbi and Madoi earthquakes occurred in late May 2021 in west China
Abstract
Abstracts: This work analyzed the electromagnetic field (EM) anomalies recorded by the electric field detector (EFD) and the search coil magnetometer (SCM) onboard the China Seismo-Electromagnetic Satellite (CSES) during the two earthquakes (EQ), which are the Yangbi Ms6.4 EQ on May 21 (China Standard Time, CST) and the Madoi Ms7.4 EQ on May 22 (CST), 2021. These two EQs successively occurred in West China. The prevailing frequency band excluding the interferences from the satellite platform was chosen to extract convincible seismic-related EM disturbances. Two criteria were put forward to obtain reliable precursors using the Kp and Dst index and the variation rate of Dst per hour to eliminate the tinier spatial perturbations. We found that the seismic-related EM disturbances mainly appeared 1–10 days before the two earthquakes within the spatial extension of 1000 km above the epicenters.