Ionospheric disturbances around the time of the Ms7.0 Lushan earthquake

Abstract: Variations of Vertical Total Electron Content (VTEC) in the ionosphere are investigated around the time of the Ms 7. 0 Lushan earthquake. A time-series analysis shows an anomalous VTEC increase 15 days before as well as some anomalous VTEC decreases 5 days before and 8 hours after the earthquake. Each of these anomalies lasted more than 4 hours and drifted from east to west. The anomalous increase 15 days before the earthquake is significantly larger than the solar-terrestrial background noise, and is thus considered to be probably related to the earthquake.