试论地质学者的地震理念

DISCUSSION ON SEISMOLOGICAL PRINCIPLE OF GEOLOGIST

地质学者认为断层是震源在地表的表现。在这一理念的基础上,文中讨论了如何通过活断层定量研究开展强震预测。强震地点预测的依据是断层活动性调查。在这方面强调航片判读和野外断层地形学的调查,由此获取断裂带的最新活动时期。对于确认的晚第四纪以来活动的断裂带,认为其将来具有发生强震的潜势。强震的活动强度从调查活断层的长度和同震位移入手。全球大量的历史地震和现今地震表明,断层长度与地震震级之间、以及同震位移与地震震级之间存在正比例关系。有关强震时间的预测,需要获知各条断裂带的强震间隔和最新活动的离逝时间。尽管通过断层的活动速率和同震位移的比值可获取断裂带的强震平均间隔,但通过探槽调查获取古地震活动的年代对分辨各条断裂带强震活动的个性特征仍十分重要。文中多处引用了日本活断层研究的资料和松田?彦教授的认识。最后简要回顾了中国活断层研究过程中的几个重要事件。

Geologist thinks that fault is the surface expression of focus. The paper discusses how to predict strong earthquake by using information of quantitative research on active faults on the basis of the principle. Prediction of places where strong earthquake occurs depends on the investigation of fault activity. Especially, interpretation of air photo and field investigation of faulted landform is emphasized to get the latest active time of fault. The fault which was active during Late Quaternary is recognized to have larger seismic potential in the future. The intensity of strong earthquake has close relations with the length of active fault and the rupture accompanied with earthquake. It is in direct proportion, which was confirmed by a lot of historical earthquakes and recent earthquakes occurring in the whole world. Prediction of time of strong earthquake needs to get the recurrence interval and the elapse time of latest activity on different fault zones. Average interval of strong earthquake may get from the ratio between active rate and the offset accompanied with earthquake on the fault. Besides, trench investigation to get times of paleoearthquakes on different faults is very important for distinguishing individual character of seismic-activity on different fault zones. A lot of information on research of active fault and recognition from Japan and Professor T. Matsuda is quoted in the paper. At last the paper briefly reviews the development of research on active fault in China.