TEC response to the 2008 Wenchuan Earthquake in comparison with other strong earthquakes

Abstract

We registered near-field global positioning system (GPS) total electron content (TEC) response to the Wenchuan Earthquake on 12 May 2008. The Wenchuan Earthquake (magnitude 8.0) occurred at 06:28 UT as the result of motion on a northeast striking reverse fault (thrust fault) on the northwestern margin of the Sichuan Basin. The earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against a strong crust underlying the Sichuan Basin and southeastern China. We found that intensive N-shaped shock-acoustic waves with a plane waveform and with a half-period of about 200 s propagated south-eastwards with a velocity 580 m s^− 1 for a distance of about 1000 km from the epicentre. The wavefront of N-shaped disturbance was parallel with the earthquake rupture direction (from southwest to northeast). The main directional lobe of shock-acoustic wave emitter is directed southeastwards, i.e. transversely to the rupture. We speculate that the above properties of TEC response are determined by the geodynamics of the Wenchuan Earthquake. No noticeable TEC response to that earthquake was found in far-field regions in South Korea and Japan. We compared TEC response to the 2008 Wenchuan earthquake with other strong earthquakes.