Comparative analysis of detected ionospheric anomalies with earthquake magnitudes: A case study of the earthquakes of March 4, 2021.

Abstract

Comparative analysis of detected ionospheric anomalies with earthquake magnitudes was carried out on two seismic events of March 4, 2021, ( M7.3 Gisborne and M8.1 Kermadec Earthquakes) to establish the link between observed perturbations and event size. GPS-TEC data were downloaded 20 days pro and 5 days post the events from stations within the epicenter of respective earthquakes. The data were statistically analyzed to detect unusual variations within the investigative window. The investigation revealed that the M7.3 Gisborne EQ recorded two variations on -19 and -4 days; both being positive perturbations. However, five anomalies were detected for the M8.1 Kermadec EQ on -15, -11, -5, -3 and -2 days. With exception of the irregularities on -3 days, all others were positive anomalies. The observed anomalies were subjected to further scrutiny using the geomagnetic indices of Kernnifzer digit (kp) and disturbance storm time (Dst.) for geomagnetically induced perturbations while sunspot number and F10.7cm were to monitor solar activities within this same period. Gisborne EQ measured 100% seismo-induced variations while Kermadec EQ had 80% seismogenic anomalies. The study clearly showed an increased in detected anomalies with earthquake magnitudes.