摘要
室内岩石破裂实验表明,主破裂前声发射事件在时间分布上随着应力增强存在着均匀—非均匀现象,本文据此提出了一个能够有效刻画强震前中小地震活动在时空分布上不均匀性的参量——地震非均匀度(GL值)。据对中国大陆1920年以来43次M_S≥7.0大震震前5年GL值时间变化扫描结果,发现除少数边界附近的大震外,所有7级大震震前1—3年,在震中一定范围内5级以上地震活动均显示出明显的非均匀状态(GL值大于1.0);同时,大震震前GL值空间扫描图象显示出,GL值的高值区(GL>1)与未来大震震中密切相关。GL值的提出为强震中期预报提供了一个行之有效的方法。
The laboratory experiments on rock fracture show that the temporal distribution of the acoustic emmission events before major fracture exhibt a homogenous-inhomo-genuous phenomenon while the stress increases. A highly efficient parameter, the inho-mogenous degree of seismicity (GL value), is put forward in this paper to describe the inhomogeneity of seismicity both in time and space prior to large earthquakes based on the fracture theory.From the temporal scanning of GL value for 43 large earthquakes (Ms≥ 7.0), authors found that there would be remarkeble anomalous changes of GL value within three years except for a few large ones according to the earthquake records (Ms≥5.0) and the authors found that the high value area (GL>1) seemed to be closely related to the later large earthquakes. It is expected that the new method proposed in this paper can play an important role in the middle-term earthquake prediction.
出处
《地震》
CSCD
北大核心
1994年第6期11-18,共8页
Earthquake
关键词
地震
非均匀度
中期预报
强震
acoustic emmission
seismic inhomogenous degree
space-time scanning of GL value
middle-term prediction
