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在龙门山中、北段发生汶川Ms8.0级特大地震5年之后,2013年4月20日在龙门山南段发生了芦山Ms7.0级地震。基于芦山地震基本特征及其所处的龙门山断裂带的构造特征、地貌水系特征、重力异常分布特征,分析芦山地震发生的区域地质背景,并探讨2013年芦山地震与2008年汶川地震之间的关系。初步获得以下认识:①芦山地震并不是汶川地震的余震,它们是两次独立的地震,芦山地震与汶川地震具有一定的关联性,汶川地震可能促进了芦山地震的发生;②下地壳流向上仰冲可能是芦山地震和汶川地震共同的成因机制,这一成因机制可以很好地解释汶川地震与芦山地震之间的空区;③龙门山南段在山前发育多条断裂和褶皱带,使得这一地区由北西向南东的应力在山前多个断裂和褶皱带得到一定的释放,因此不具备发生类似汶川地震这样特大地震的构造条件。
In Longmenshan, after a Wenchuan earthquake of magnitude Ms8.0 occurred in the northern section, a Ms7.0 Lushan earthquake occurred on the southern segment of Longmen Shan on April 20, 2013. Based on the basic characteristics of Lushan earthquake, the structural features of Longmen Shan fault zone, the features of geomorphic water system and the distribution of gravity anomalies, the regional geological background of Lushan earthquake is analyzed and the relationship between the Lushan earthquake in 2013 and the Wenchuan earthquake in 2008 relationship. The following acquaintances are obtained: (1) The Lushan earthquake is not an aftershock of the Wenchuan earthquake. They are two independent earthquakes. The Lushan earthquake has some correlation with the Wenchuan earthquake. The Wenchuan earthquake may have contributed to the Lushan earthquake. (2) The red may be the common genetic mechanism of the Lushan and Wenchuan earthquakes. This genetic mechanism can well explain the vacant space between the Wenchuan and Lushan earthquakes. In this area, the stress from northwest to southeast reaches some faults in the front of the piedmont and the fold belt is released to a certain extent. Therefore, it does not have the tectonic conditions of such a big earthquake like the Wenchuan earthquake.