| 重庆垫江MS4.4地震:一个可能发生在浅地表的地震 |
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| 引用本文： | 黄世源,李翠平,王赞军,高见,郭卫英.重庆垫江MS4.4地震:一个可能发生在浅地表的地震[J].地震学报,2020,42(1):34-43. |
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| 作者姓名： | 黄世源 李翠平 王赞军 高见 郭卫英 |
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| 作者单位： | 中国重庆 401147 重庆市地震局 |
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| 基金项目： | 地震科技星火计划项目（XH18037Y）和重庆市地震局科技创新团队项目共同资助 |
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| 摘 要： | 为更好地认识2016年8月11日重庆垫江MS4.4地震的发震成因，本文首先分析了近场地震台站记录到的该地震产生的短周期面波（Rg）强频散现象，该现象表明本次地震具有明显的浅震特征。然后采用CAP方法反演了该地震的震源机制解和震源深度，结果显示本次地震是走向为近EW向的逆冲型地震，矩震级为MW4.1，最佳震源深度为1—2 km。在此基础上，结合现场震害、烈度等震线长轴方位和地质剖面图等资料，分析认为在区域应力集中加载作用下，震源区沉积盖层内部的软弱地层产生挤压变形，导致地层内斜交的裂隙发生切层失稳滑动，从而诱发了垫江MS4.4地震，同时排除了震源区NE走向的黄钦垭口地表断层为发震构造的可能。
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| 关 键 词： | 重庆垫江MS4.4地震 震源深度 震源机制解 地震成因 |
| 收稿时间： | 2019-05-23 |
Dianjiang，Chongqing，MS4.4 earthquake:A possible shallow surface earthquake |
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| Affiliation: | Chongqing Earthquake Agency，Chongqing 401147，China |
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| Abstract: | In order to better explore the causes of the MS4.4 earthquake occurred on August 11 2016, in Dianjiang, Chongqing, this paper analyzes the strong dispersion of Rayleigh surface wave, and the phenomenon suggests that this earthquake has obvious shallow-source earthquake characteristics. Then, we obtained the focal mechanism and focal depth of the earthquake with CAP method. The results show that the earthquake is a thrust event with strike of nearly EW-trending, the moment magnitude is MW4.1 and the estimated focal depth is 1?2 km. Finally, from the comprehensive research on mechanism solution, earthquake field damages, the isoseismal curve major axis direction and the geological section, we conclude that the Dianjiang MS4.4 earthquake is caused by the slip of oblique fractures in the interlayers resulted from compressive deformations of soft strata in sedimentary covers under the concentrated loading of the regional stress field, excluding the possibility of the NE-trending Huangqinyakou fault as the seismogenic structure of the Dianjiang MS4.4 earthquake. |
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