Wenchuan M8. 0 earthquake brought large disaster to China on May 12 2008. And earthquake prediction becomes a hot topic again in the world. Due to the impossibility of entering the earth interior and complexity of earthquake preparation mechanism, earthquake prediction is still a worldwide problem. Scientists have to employ limited observing technology to summarize kinds of features shown in the process of earthquake preparation in the hope of accumulating knowledge to seismic mechanism. In recent years, many electromagnetic observing technologies have been developed including those at surface and satellite to detect the changes of underground media or ionospheric variations (Varotsos, et al., 1993; Hayakawa, et al., 1996; Molchanov, et al., 1996; Parrot, et al., 2006). The results reflects that electromagnetic signals may be an useful tool in short-term earthquake prediction because the anomalous electromagnetic signals often occurred just a few days or a few hours before strong earthquakes.
Wenchuan Earthquake Electromagnetic Perturbation DEMETER Satellite Geomagnetic Field Electron Density
Institute of Earthquake Science, CEA, Fuxing Road 63, Haidian district, Beijing 100036, China Institute of Earthquake Science, CEA, Fuxing Road 63, Haidian district, Beijing 100036,China Institute of Earthquake Science, CEA, Fuxing Road 63, Haidian district, Beijing 100036, Chin Institute of Earthquake Science,CEA, Fuxing Road 63, Haidian district, Beijing 100036, China