中国及邻区现代构造形变特征

CHARACTERISTICS OF THE RECENT TECTONIC DEFORMATIONS OF CHINA AND ITS VICINITY

  • 摘要: 本文根据大量浅源地震机制解, 地面地震地质调查、资源卫星影像判读和其它地球物理资料、讨论了我国及其邻区现代构造形变的区域特征.它具体反映在我国东部地区, 现代构造形变是以剪切破裂为主, 断层活动多为北北东—北东向的右旋走滑性质, 也有与之共轭的北西西—北西向的左旋走滑性质的断层活动.西部地区则以压缩形变为特征, 主要表现在以青藏高原为主体的凸向东北的四重弧形构造带上, 在第一和第四弧形带的东北部以挤压引起的逆断层活动为主, 第二和第三弧形带是在挤压作用下, 由于物质的横向推移而引起的走滑断层活动.此外现代构造形变的区域特征还反映在地壳厚度的分布轮廓上.造成我国及邻区这样一种现代构造形变特征的原因是与周围几个板块运动有密切关系的.

     

    Abstract: In this paper, regional characteristics of recent tectonic deformations in China and its vicinity are discussed. The work is based on a great amount of data of the fault plane solutions of shallow earthquakes, field seismo-geological surveys and of the Landsat imageries and some other geophysical observations. The results of the analysis, show that in eastern China, a predominat feature of recent tectonic deformation appears to be shear fractures, consisting of dextral strike-slip faulting with directions from NNE to NE. There are also a few conjugating strike-slip sinistral faults with directions from NWW to NW. In western China, recent tectonic deformations are characterized by compressions of which the most outstanding features are the four successive arcuated tectonic belts convex to the northeast of the Qinghai-Xizang (Tibet) Plateau. The first arcuated tectonic belt and the northeastern part of the fourth belt are mainly thrusting due to compression. The second and third arcuated tectonic belts are dominated by strike-slip faults due to lateral compression. Regional characteristics of the recent tectonic deformations are also reflected by the regional distributions of crustal thickness. Recent tectonic deformations of China and its vicinity are closely related to the movements of the surrounding tectonic plates.

     

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