Near-field TEC response to the main shock of the 2008 Wenchuan earthquake

We have registered near-field TEC response to the Wenchuan earthquake on 12 May 2008, for the first time. We found that an intensive N-shape shock-acoustic wave with a plane waveform and with half-period of about 200 sec propagated south-eastward with a velocity of 600 m/s for distance about 1000 km. The wavefront of N-shaped disturbance was parallel with the earthquake rupture direction (from SW to NE). The main directional lobe of shock-acoustic wave emitter is directed southeastward, i.e. transversely to the rupture. We suppose that the above properties of TEC response are determined by the geodynamics of the Wenchuan earthquake.