The observation and research on pre-earthquake electromagnetic radiation information

By use of the specialized under ground electrodes as the sensor, the Experimental Multi-station Network observed Seismic Electromagnetic radiationsprior to the moderately strong earthquake. From the great number of electromagnetic anomalies recorded by the network continuously for about 10 years, it can be sure that the anomalies are related to earthquakes aboveM _s 5 within 300 km. The stronger the magnitude of the earthquake is, the better the relation is. The abnormal electromagnetic radiation information appears in a short-time before the moderately strong earthquake. The continuous automatic pen recording shows that the electromagnetic information is the waveform of the paroxysmal wave group, and has the features of undulating enhancement, amplitude in inversely proportion to epicentral distance, frequency increase, regional similarity of wave froms and directivity, etc.. It also contains some quantitative elements related to the parameters of the earthquake. The above characteristics and correlative elements can provide important bases for predicting the three elements of the earthquake. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 83–90, 1993. Associate Professor Da-Yuan CHANG and Teacher Feng CHEN have gave us a lot of help during the study.