关键词: 氦氢异常, 时空强特征, 地震关系

Abstract: Based on the measuing data from 9 observation points and the cases of 5 moderate earthquakes in North China during the time period from 1989 to 1991,the relationship between the anomaluos release of subsurface helium and hydrogen gasses and the occurrence time,locality and magnitude of earthquake has been discussed in this paper.An empirical method was proposed for determining the three main elements of earthquake prdeiction.It is proposed that the occurrence time of a possible earthquake can be predicted on basis of synchronus anomaly of helium and hydrogen in various observation points, and specially the dropping and truning of the curves of anomalies.The possible locality of earthquke occurrence can be delineated according to the fact that the starting time of the anomaly becomes later toward the epicentral area,i.e.the closer to the epicentral area,the later the starting time of the anomaly.The magnitude of the predicted earthquake can be estimated through the intensity (a combination of duration time and amplitade )and range of anomaly,as well as the number of the observation points that show anomalous release of helium and hydrogen gasses.

Key words: Gas geochemical surveys, Groundwater anomaly, Earthquake prediction, North China