| 2017年9月2日宁夏固原4.6级地震震例分析 |
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| 引用本文： | 李文君,曾宪伟,卫定军,李国斌,罗国富.2017年9月2日宁夏固原4.6级地震震例分析[J].地震地磁观测与研究,2020(1):40-47. |
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| 作者姓名： | 李文君 曾宪伟 卫定军 李国斌 罗国富 |
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| 作者单位： | 宁夏回族自治区地震局 |
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| 基金项目： | 中国地震局地震科技星火计划(项目编号:XH18053Y);宁夏地震科研基金课题(项目编号:NX201903)。 |
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| 摘 要： | 2017年9月2日宁夏固原市原州区发生4.6级地震.通过对此次地震的回顾和总结,得到以下结论:①固原4.6级地震为孤立型地震;余震主要分布在主震震中西南侧,结合震源机制节面解,初步判定NW向节面应为此次地震的发震断层面,震源错动方式为左旋走滑兼具逆冲;震源机制解最佳拟合深度为9 km;震源机制解参数为节面Ⅰ:走向34°、倾角62°、滑动角174°,节面Ⅱ:走向127°、倾角85°、滑动角28°;②固原4.6级地震前存在前震活动、小震调制异常以及固原地震窗异常;③海原小山钻孔应变异常变化与固原4.6级地震有关,且与该测项预测指标已有的研究结果较吻合,但此次地震震级比预计震级偏大;④固原地震台地电阻率和地磁谐波振幅比异常期间发生了3次中强地震,其中,2017年5月17—20日,固原地震台地电阻率EW向出现快速下降,之后呈低值变化;固原地震台地磁谐波振幅比NS向从2014年开始经历下降—转折—回升过程,具有良好的映震效能.
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| 关 键 词： | 固原地震 震源机制 小震调制比 固原地震窗 钻孔应变 |
Analysis of Guyuan M 4.6 earthquake on September 2,2017 in Ningxia |
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| LI Wenjun,ZENG Xianwei,WEI Dingjun,LI Guobin,LUO Guofu.Analysis of Guyuan M 4.6 earthquake on September 2,2017 in Ningxia[J].Seismological and Geomagnetic Observation and Research,2020(1):40-47. |
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| Authors: | LI Wenjun ZENG Xianwei WEI Dingjun LI Guobin LUO Guofu |
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| Institution: | (Earthquake Agency of Ningxia Hui Autonomous Region,Yinchuan 750001,China) |
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| Abstract: | On September 2,2017,an M 4.6 earthquake occurred in Yuanzhou District,Guyuan City,Ningxia Hui Autonomous Region.Based on the review and summary of the earthquake,the following conclusions can be drawn:①Guyuan M 4.6 earthquake is an isolated earthquake;aftershocks are mainly distributed in the southwest of the epicenter.Combined with the focal mechanism nodal plane solution,it is preliminarily determined that the NW-trending nodal plane should be the fault plane of this earthquake,and the source dislocation mode is both left-lateral strike-slip and reverse.Rush.The optimum fitting depth of focal mechanism solution is 9 km.The focal mechanism solution parameters are nodal I:strike 34°,dip 62°and slip 174°;nodal II:strike 127°,dip 85°and slip 28°.②Before the Guyuan M 4.6 earthquake,there were foreshock activities,small earthquake modulation anomaly and Guyuan earthquake window anomaly.③The variation of borehole strain anomaly in Xiaoshan,Haiyuan is related to Guyuan M 4.6 earthquake,and is in good agreement with the research results of prediction index of this item,but the magnitude of this earthquake is larger than the predicted magnitude.④Three moderate-strong earthquakes occurred during the period of abnormal development of Guyuan geo-resistivity and Guyuan geomagnetic harmonic amplitude ratio.From May 17 to 20,2017,the EW of Guyuan geo-resistivity declined rapidly and then changed to a low value.The curve of Guyuan geomagnetic harmonic amplitude ratio NS to different periods has experienced a decline-turn-rise since 2014.Cheng has good seismic reflection ef ficiency. |
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| Keywords: | Guyuan earthquake focal mechanism small earthquake modulation ratio Guyuan seismic window borehole strain |
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