滇西南地区双震序列应力触发及地震活动性研究  

Comparative analysis on stress triggering of double earthquakes sequence and seismicity in southwest part of Yunnan Province

作　　者：刘方斌[1,2] 袁道阳[1,3] 王爱国[1,3] 庞炜[1] 

机构地区：[1]中国地震局兰州地震研究所 [2]山东省地震局,济南市历下区文化东路20号250014 [3]兰州地球物理国家野外科学观测研究站,兰州730000

出　　处：《中国地震》2015年第3期472-480,共9页Earthquake Research in China

基　　金：公益性行业科研专项<中国地震活断层探察-南北地震带中南段>(201108001)资助

摘　　要：利用弹性半空间模型和岩石圈介质波速模型,计算了1976年龙陵7.3、7.4级地震和1988年澜沧-耿马7.6、7.2级地震2次双震间及对后续地震的应力变化影响,同时对该区未来地震活动性进行了研究。得到以下结论:1龙陵双震属共轭型双震活动,前一次地震的发生对后一次地震有抑制作用;而澜沧-耿马地震则属于牵动型双震活动,澜沧7.6级地震对其后的耿马7.2级地震有一定的触发作用,其库仑应力变化值为0.35bar;2绝大多数后续余震受到了主震的应力触发作用,其中龙陵双震触发效果较明显;3根据震后粘弹性松弛应力场变化得出,现阶段NW向的腾冲-龙陵、永德-勐省以及澜沧东南地区,NE向的瑞丽、镇安、大理、上允、永平等地区地震危险性有所增强,这与该区地震活动性增强相吻合。The southwest part of Yunnan Province is located in the northeast of Indian plate and Eurasian plate,southeast edge of the Qinghai-Tibetan Plateau,which is one of the strongest tectonic activity areas in China. The Longling and Lancang-Gengma earthquakes are typical doubleearthquakes in this area. Based on Okada＇s elastic half-space model and medium wave velocity model of lithology,we calculated Coulomb stress changes of two between double earthquakes and aftershocks. Meanwhile,we analyzed the seismicity of this area. The results showed that： （1）The Longling earthquakes were conjugate and Lancang-Gengma earthquakes were opposite ;they were the affecting type. Due to this result,which made the Gengma earthquake in the area with ACFS〉O,and the value is 0.35bar. （2）With double earthquakes triggering subsequent aftershocks,because of the Coulomb stress changes of Longling double earthquakes, which triggered most of all aftershocks. The trigger effect was far greater than Lancang-Gengma earthquakes. （3） Based on the viscoelastic relaxation effects after earthquakes, we concluded that the seismic hazard will be higher in the NW--Tengchong-Longling, Yongde-Mengsheng and the southeast of Lancang, the NE--Ruili, Zhenan, Dali and Yongping areas,which is consistent with the distribution of seismic activity.

关 键 词：滇西南地区 龙陵地震 澜沧．耿马地震 应力触发 地震活动性 

分 类 号：P315[天文地球—地震学]