Atmospheric and ionospheric disturbances associated with the M > 6 earthquakes in the East Asian sector: A case study of two consecutive earthquakes in Taiwan

Abstract

The phenomenon of Lithosphere-Ionosphere coupling is a popular topic for researchers for the last two decades. This study aims to analyze the seismo-ionospheric anomalies (SIAs) in East Asia induced by the M > 6 earthquakes (EQs) from Total Electron Content (TEC) of permanent IGS stations operating around the vicinity of the corresponding epicenters by considering a case study of two successive EQs from Taiwan. Our results showed remarkable TEC enhancements one day before both impending EQs during quiet geomagnetic activity (Kp less than 3, Dst ≥ −20), where the variations were found one day before each EQ during UT = 02–08 (LT = 10–16) hours in the form of differential TEC (dTEC). On the other hand, V-shaped gradual decreases in temporal atmospheric parameters took place one day before the M 6.1 EQ that gradually decreased till the M 6.4 EQ day before turning back to normal. The anomaly maps of geopotential height and surface air temperature showed intense decreases and the consequent OLR enhancements right along the edge of the Philippine Sea plate in the northwest direction. Furthermore, we observed a distinctive phenomenon of equatorial ionization anomaly (EIA) enhancement in the latitudinal GIM-TEC profiles near the epicentral longitude, where the EIA structure modified the shape as a double crust structure with a trough near to the equator that testifies the generation of the seismogenic electric field. Our multi-precursory study is another contribution in the acknowledgment of LAI coupling (Lithosphere, Atmosphere, Ionosphere) hypothesis in the prediction of the future EQs.