2016年9月23日四川理塘M4.9和M5.1地震发震构造分析

发布时间：2018-01-30 12:48

本文关键词： 理塘M.和M.地震重新定位震源机制发震构造　出处：《地震地质》2017年05期 　论文类型：期刊论文

【摘要】：2016年9月23日,在四川西部理塘县相继发生M4.9和M5.1地震,震中位于青藏高原东缘川滇块体西北部金沙江断裂带与理塘断裂带所夹持的区域。文中基于四川区域地震台网提供的震相报告和波形资料,采用多阶段定位方法,对理塘M4.9和M5.1主震及余震序列进行了重新定位。同时,利用CAP波形反演方法,获得了这2个主震的震源机制解、震源矩心深度与矩震级。根据重定位后的余震空间分布形态、M4.9和M5.1主震的震源机制解,结合等震线形态及震中附近主要构造的展布,分析认为,近EW走向、倾向N的哈嘎拉断裂带为理塘M4.9和M5.1地震的发震构造,与该断裂带走向和倾向一致的节面Ⅰ为同震断层面,断面倾角44°。理塘M4.9和M5.1地震可能是在西侧羌塘块体物质持续E向挤入作用下、位于理塘—巴塘地区上地壳内的近EW向哈嘎拉断裂张性运动所致。
[Abstract]:In September 23rd 2016, M4.9 and M5.1 earthquakes occurred successively in Litang County, western Sichuan. The epicenter is located in the area between the Jinshajiang fault zone and the Litang fault zone in the northwest of Sichuan-Yunnan block on the eastern margin of the Qinghai-Xizang Plateau. This paper is based on the seismic phase report and waveform data provided by the Sichuan regional seismograph network. By using multi-stage localization method, the main shocks and aftershock sequences of M 4.9 and M 5.1 in Litang are relocated. At the same time, the focal mechanism solutions of the two main shocks are obtained by using the CAP waveform inversion method. The focal moment center depth and moment magnitude. Based on the focal mechanism solutions of the aftershock spatial distribution patterns M 4.9 and M 5.1, combined with the isoseismal shape and the distribution of the main structures near the epicenter, it is considered that. Near the EW strike, the Hagala fault zone with a tendency to N is the seismogenic structure of the Litang M 4.9 and M 5.1 earthquakes, and the joint plane I, which is consistent with the strike and tendency of the fault zone, is the co-seismic fault plane. The inclined angle of the section is 44 掳. The earthquakes of Litang M 4.9 and M 5.1 may have been caused by the continuous E entrainment of the Qiangtang block on the west side. The near EW-Hagala fault extensional movement in the upper crust of the Litang-Batang area.
【作者单位】：四川省地震局;四川赛思特科技有限责任公司;
【基金】：国家自然科学基金(41574047) 四川赛思特科技有限责任公司西部大开发优惠政策节税资金投资项目(XDK2015001) 四川省外国专家局引智项目(S201637) 2017年地震监测预报跟踪专项共同资助
【分类号】：P315.2
【正文快照】： 0引言2016年9月23日0时47分,在四川省甘孜藏族自治州理塘县发生M4.9地震,0.5h后,距其震中西北约3km处,于1时23分再次发生M5.1地震。四川省地震局根据震区震害调查和强震动观测记录,给出了本次地震的等震线(烈度)分布,等震线呈不规则椭圆状分布,长轴近EW向,最高烈度Ⅵ度(图1)。

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