Electromagnetic radiation anomalies before moderate and strong earthquakes

• DOI: 10.1007/bf02650493
• Publication Date: 2007-08-15T07:36:17Z
• Authors: Hua-Ping Guan; Gui-Ping Liu
• Keywords: 0103 physical sciences; 01 natural sciences; 0105 earth and related environmental sciences

Electromagnetic radiation observations have been developed since the 1976 Tangshan earthquake. Up to now, 130 observatories have been set up in China. The present observation frequency ranges are ultra-low frequency 0.01–20 Hz and point frequency from 103 to 104 Hz. In the past 20 years, more than 40 earthquakes aboveM5.0 were recorded. By analyzing the earthquake examples, it is demonstrated that the distances between the anomalies recorded at observatories and the event were related with earthquake magnitude; the lasting time of anomalies are from several seconds to several ten days; during most of these events no electromagnetic radiation were observed simultaneously. In addition, the detail features of the electromagnetic radiation anomalies were discussed in this paper.