Anomalous changes in ionospheric TEC during an earthquake event of 13–14 April 2010 in the Chinese sector

Abstract

The earth’s ionosphere is considered susceptible to the seismic effects and the detection of such ionospheric perturbations associated with the earthquake has become a challenge for the short-term prediction of earthquakes. In this paper, an investigation of the changes in the ionospheric behavior is reported which may be associated with M 6.9 and its aftershock of 6.1 magnitude earthquakes at Qinghai station (geog. 33.19N, 96.75E, geom. 23.90N, 169.98E) which occurred on 13 April (23:49 UT, 06:19 LT on 14 Apr) and 14 April 2010 (01:25 UT, 06:55 LT) respectively. The observations are made using ionospheric total electron content (TEC) obtained from 10 available IGS stations in the Chinese and 2 in the Indian sector to detect seismo-ionospheric anomalies if they exists. We found anomalous depletions in the ionospheric regions 3–4 days (on 10 April 2010) up to 4 TECU before the earthquake over stations close to the epicenter (<1700 km). The anomalous changes in the ionosphere are observed firstly over a distant station (wuhn, 0800–1600 UT) during afternoon to midnight hours and few hours later over the near-by stations to the epicentre in the nighttime (1500–2300 UT, 2100–0500 LT). Our results from the case study suggest that these anomalies in ionospheric TEC may be the possible seismo-ionospheric signatures for the considered earthquake in the Tibetian plateau region. 2015 COS