摘要
对2015年3月1日沧源5.5级地震的震源机制解、余震区走向综合分析认为南汀河断裂西支为此次地震的发震构造;通过对前震活动时空动态演变的研究进行分析,震前震中150 km左右范围,小震活动在主震8个月前开始出现增频现象,震前3个月地震活动积累频度进一步加速发展,震前13天达到最大值,随后进入震前临震的高度平静阶段;墨江作为滇西南显著的地震窗口,曾在沧源5.5级地震前8天发生4.4级地震;震前存在可识别的孕震区,并根据该孕震区的最大尺度和最大前震对未来主震震级作定量计算,所预测震级与实际发生震级基本符合;在前兆观测项目上,耿马、云县洞体应变北东向和水管倾斜北东向均出现破年变异常。通过该次地震孕震过程分析认为:沧源5.5级地震孕震过程的中、短、临前兆阶段是可跟踪、可计算的,研究分析结果可为今后本区内破坏性地震的监测提供参考。
Based on a comprehensive analysis of the focal mechanism solution, isoseismal line distribution of intensity and the trend of aftershock zones of Cangyuan M 5.5 earthquake on March 1st, 2015, it is believed that the west branch of Nanting River fault is the seismogenic structure of this earthquake. The study of spatiotemporal dynamics evolution of foreshock activities before earthquake shows that before earthquake the epicenter＇s range is about 150 km, small earthquake activities begin to increase and appear abnormal phenomena eight months before the principal earthquake, and the accumulative frequency of earthquake activities further accelerates development 3 months before earthquake, and reaches its maximum 13 days before earthquake, then enters the highly calm phase of the imminent earthquake before earthquake. There existed an identifiableseismogenic zones before earthquake, and according to the largest scale and the largest foreshock of this seismogenic zone, the future main shock magnitude can be quantitatively calculated. At the same time, the north east eomponent of cave strain and water pipe tilted in Gengma county and Yun county appeared the annual variation; through the seismogenie process analysis of this earthquake, it is considered that the middle phase, short phase and temporary phase of the preparation of Cangyuan M 5.5 earthquake, are all trackable and computable, which provides a reference for the monitoring of destructive earthquakes in this area in the future.
出处
《华南地震》
2017年第2期39-47,共9页
South China Journal of Seismology
关键词
沧源Ms
5.5地震
前兆异常
异常特征
南汀河断裂
Cangyuan Ms 5.5 earthquake
Precursory anomaly
Anomaly characteristie
Nantinghe fault zone
