从龙门山地质地貌分段性探讨芦山地震与汶川地震的关系*

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。

The relationship between Lushan earthquake and Wenchuan earthquake by segmentation of geology and geomorphology of Longmen Shan

After the appearance of Wenchuan M8.0 earthquake in central-northern segment of the Longmen Shan in 5th anniversary,Lushan earthquake in the southern segment of Longmen Shan appeared on April 20, 2013. Based on the basic characteristics ofLushan earthquake and the tectonic，geomorphic，water system，the distribution of the gravity anomaly characteristics of LongmenShan Fault zone to analyze the regional geological background of Lushan earthquake and explore the relationship between the Lushan earthquake and wenchuan earthquake, we draw the following conclusions: ① the Lushan Earthquake is not the aftershocks of Wenchuan Earthquake ,they are two independent earthquake and has some relevance, the appearance of Wenchuan earthquake could promote the Lushan earthquake; ② the obduction of lower crustal flow may be the common genetic mechanism of the Lushan Earthquake and Wenchuan Earthquake, which can well explain the empty area between them; ③ there are many faults and folds in the front of the southern segment of Longmen Shan, to some extent, which can release the stress from the northwest to the southeast in this zone. Therefore, the southern segment of Longmen Shan do not have the tectonic background of the Wenchuan Earthquake.