2014年云南景谷M_S 6.6地震序列双差定位及震源机制解特征研究  

Research on Double-difference Relocations and Focal Mechanism Solutions of the 2014 Yunnan Jinggu M_S6.6 Earthquake Sequence

作　　者：李丹宁[1] 高洋[1] 朱慧宇 秦敏[1] 张会苑 徐彦 LI Danning GAO Yang ZHU Huiyu QIN Min ZHANG Huiyuan XU Yan(Yunnan Earthquake Agency, Kunming 650224, Yunnan, China University of Science and Technology of China, Hefei 230026, Anhui , China School of Resource Environment and Earth Science, Yunnan University, Kunming 650091, Yunnan, China)

机构地区：[1]云南省地震局,云南昆明650224 [2]中国科技大学,安徽合肥230026 [3]云南大学资源环境与地球科学学院,云南昆明650091

出　　处：《地震研究》2017年第3期465-473,共9页Journal of Seismological Research

基　　金：测震台网青年骨干培养专项--2014年以来云南M6以上地震序列特征分析及震区构造活动性研究(20150426);国家自然科学基金--小滇西地区发震断层及应力状态研究(41564003);地震行业科研专项--应用互联网图像搜索引擎技术实现实时地震监测技术的研究(201408018)联合资助

摘　　要：结合波形互相关技术,运用双差定位方法对2014年景谷M_S6.6地震及其强余震序列进行重定位。对序列中2.0≤ML≤5.0共730个事件重定位得到649个重定位结果。定位误差在EW向为18 m,NS向为19 m,深度方向为23 m。结果显示此次景谷地震序列主要沿2个优势方向展布:一个是主震发生后沿NW走向的无量山断裂西支(普文断裂)延长线呈长约20 km的带状分布,一个是12月6日MS5.8和MS5.9两个强余震发生后沿近NS向长度约10 km左右的展布,这可能与西侧的NNE走向的澜沧江断裂及东侧NW走向的无量山断裂西支(普文断裂)共同作用有关,也有可能是发震断层分段破裂或分段活动造成的结果。从深度上看,序列大部分地震集中分布在6~15 km深度范围内,而在12月6日强余震发生几天后,序列地震的深度有一个整体变深的趋势,分布范围主要集中在9~16 km,这与序列位置及走势发生变化有关,也提示了研究区域地质结构的复杂性。我们用全波形模拟法得到了序列中M_S≥3.5地震震源机制解,主震北侧发生的地震,震源机制与主震一致性较好;而主震南侧的地震,其震源机制解主破裂面走向有向NS向偏转的趋势。Using the double - difference method that combined with waveform cross - correlation, we relocated the Jinggu Ms6.6 and its 730 aftershocks with magnitude between 2 and 5 and finally obtained 649 relocated earth- quakes, the statistical location error are 18 m in EW, 19 m in NS and 23 m in depth direction, respective- ly. The aftershock sequence presents a zonal shape with lengths of 20km and along the west branch of Wuliangs- han fault （Puwen fault） . But two strong aftershocks sequence distribution direction has some transformation, mainly along the nearly NS with length of 10 km after the strong aftershocks with Ms5.8 and Ms5.9. This may be associated with fracture on the west side of NNE direction of the Lancang river fault and on the east side of NW direction of the west branch of Wuliangshan fault （Puwen fault）, also may be related to segmental rupture or segmental activity of fault. Most earthquakes are predominately located between 6 km and 15 km. But the depth of the earthquake sequence has the tendency of a whole deeper distribution range are mainly concentrated in 9 km to 16 krn a few days later. This indicates the complexity of the regional geological structure. Using full waveform simulation method to get the focal mechanism solution of Ms 〉 3.5 earthquakes, the focal mechanism of the north earthquakes is consisted with the main shock. The strike of plane I of the south earthquakes have a trend to- wards NS.

关 键 词：景谷MS6.6地震 波形互相关 双差定位 震源机制解 

分 类 号：P315.72[天文地球—地震学]