地质构造研究和地震测深剖面的构造解析显示,龙门山碰撞造山带岩石圈存在既有显著差异又有密切联系的两套断裂系统:一是以地壳表层脆性剪切带为主的浅层断裂系统;另一是以切割莫霍界面或壳幔过渡带的壳幔韧性剪切带为主的深部断裂系统。根据地质构造和地震测深成果的综合研究,在建立起龙门山造山带及邻区岩石圈地壳结构模型的基础上,论述了两套断裂系统的特征与相互关系,提出岩石圈壳幔韧性剪切带可能是四川汶川8.0级强烈地震的发震构造之一,以及强烈地震形成的动力学模式等。
Based on a structural analysis of many seismic sounding profiles,there are two fault systems in Longmen collisional orogenic belt,Sichuan,China.They are both different obviously and correlative closely.One is shallow fault system composed mainly of brittle shear zones in surface crust,and the other is deep fault system composed mainly of crust-mantle ductile shear zones cutting Moho discontinuity.Based on the result of researching geological structure and seismic sounding profiles,the authors give a lithospheric crustal structure model of the Longmen orogenic belt and its adjacent areas besides generalizing the feature and relationship of the two fault systems.The authors think that the lithospheric crust-mantle ductile shear zone is one of the seismogenic structures and put forward the geodynamic model of a major earthquake.