云南地区近期强震重复发生时地震学的动态演化特征  

CHARACTERISTICS OF SEISMOLOGICAL DYNAMIC EVOLUTION IN THE RECENT RECURRENCE OF STRONG EARTHQUAKES IN YUNNAN AREA

作　　者：蔡静观[1] 张喜玲[1] 李永莉[1] 王兴辉[1] 雷素华[1] 

机构地区：[1]云南省地震局

出　　处：《地震研究》1997年第4期357-364,共8页Journal of Seismological Research

摘　　要：通过对强震重复发生的滇西北、滇东北、滇西南澜沧江以西３个地震区多项地震活动性和地震波参数的动态追踪，发现在同一地震区重复发生的强震，震前的异常形态可以具有相似性，也可以出现反向变化的特征。如滇东北地震区中小地震在１９８５年禄劝强震前的活跃和１９９５年武定强震前的平静；澜沧地震台单台波速比月均值在１９８８年澜沧—耿马大震前的低值异常和１９９５年孟连西中缅边境大震前的高值异常。本文同时以ｂ值和波速比为例，讨论了强震成组发生时强震所在的地震区和未发生强震的地震区各自不同的变化特征。结果表明：发生了强震的地震区，在强震前２—８年，ｂ值均出现高达１．８０的突变异常，而未发生强震的滇西地震区ｂ值最大值为１．５０，从而提出了中长期源兆的问题；同样，单台波速比在强震震中附近的台站，其高值突变的幅度要比远离强震震中的台站大２０—６０％。Through dynamic tracing of multi-seismic activities and seismic wave parameters in the three areas of north-west Yunnan, north-east Yunnan and west of Lancang River of south-west Yunnan where strong earthquakes occurred, it is found out that the anomalous forms could be similar, or opposite before the strong earthquakes reoccurred in the same seismic area. For instance, small earthquakes in north-east Yunnan area were active before Luquan earthquake in 1985 and quiescent before Wuding earthquake in 1995; the monthly mean values of ratio of velocity at Lancang station anomaly appeared anomalies with low values before Lancang-Gengma earthquake in 1988, and anomalies with high values before Menglian earthquake in 1995. Taking b value and ratio of velocity as examples, different variation features, such as seismic area where strong earthquake occurred and where without strong earthquake, have been discussed in this paper. The results show that in the seismic area where strong earthquake had occurred, mutation anomaly of b value as high as 1.80 appeared 2-8 years before strong earthquake; and it the area of west Yunnan where without strong earthquake, the maximum value of b was 1.50, which has put forward a problem of source precursors with long-medium term. Similarly, mutation amplitude of high value for ratio of velocity at single station near the epicenter of strong earthquake is 20-60% bigger than that where far away from the epicenter.

关 键 词：地震复发 地震活动性 地震波 地震学 动态演化 

分 类 号：P315[天文地球—地震学] P315.3[天文地球—固体地球物理学]