摘要
本文研究了云南三次７ 级以上强震前的小震活动， 前兆异常总台项频数变化， 地下水时空特征。得出在大震前３ ～６ 个月前兆异常台项总频数的升高现象与３０ ～３９ 级小震向震中区收缩的时间大致同步， 可能是大震前的异常从短期向短期临震过渡的时间标志。震前１ ～３ 个月出现的前兆台项总频数异常峰值和水位、水氡的场兆现象则是异常进入短期临震的时间； 峰值回落是震源区进入临震状态的时间。
Small earthquake activity before the three strong earthquakes with over M 7, variation in total frequency numbers of precursor terms and the stations with the precursors and time space characteristics of qroundwater are studied in this paper. It is obtained that rising of the total frequency numbers of the precursor terms and the stations with precursors synchronized rougnly with drawing back of small events with M 3.0～3.9 into the epicentral regions three to six months before the large earthquakes, which might be the time symbol of transition from short term anomalies to short impending anomalies before the large earthquakes. The field precursor phenomenon of the peak anomalies of the total frequency numbers of the precursor terms and the stations with the precursors and water level and radon in groundwater occurred one to three months before the earthquakes indicated that the anomalies had entered short impending earthquake stage, and a fall in the peak meant the focal regions had entered impending earthquake stage.
出处
《地震研究》
CSCD
北大核心
1999年第3期221-227,共7页
Journal of Seismological Research
基金
95 - 04 - 03 - 01 - 04 子课题
关键词
前兆异常
台项总频次
地震预报
强震
时空点
Toatl frequency of precursor terms and stations with precursors, epicentral location, error, variation relation between field and source, frequency in a month, relation between time and distance
