摘要
根据重力、航磁及地震波传播速度等地球物理资料，研究了天山地区的深部构造特征。发现天山两缘是地壳物质组成变化较大的场所，也是介质结构最不稳定的区域。地震的发生不仅涉及到地表断裂构造的分布和活动方式，而且与深部物质的非均匀程度有一定的联系。大部分中强地震都发生在地壳中部附近不同速度体之间的梯度带附近，那里是深部介质分布最不均匀的构造层位。它的存在与中强地震的孕育场所密切相关，在构造应力的作用下很容易发生形变甚至破裂引发地震。
The deep structure in Tianshan area are studied on the basis of data of gravity,aeromagnetism and P wave propagating velocity.It is found that both the flanks of Tisnshan have some locations with large variations of materisl composition and unstable crustal structure. Earthquakes occurred in this area are not only related to the active pattern and distribution of surfsce faults,but to the inhomogeneous level of deep material in crust. Most moderate and strong earthquakes occurred in the gradient belt between different velocity blocks around middle crust,with strong inhomogeneity. Its existance is closely related to the development of the moderate and strong earthquakes and crustal medium will be deformed or fractured easily under the force of teCtonic stress.
出处
《内陆地震》
1995年第3期242-249,共8页
Inland Earthquake
关键词
天山
地壳结构
非均匀介质
上地幔
地震
分布
Tianshan
Crustal structure
Inhomogeneous medium
Upper mantle Velocity distribution
Earthquake distribution
Gravity field Geomagnetic field
