The crustal isostatic anomaly beneath eastern Tibet and western Sichuan and its relationship with the distribution of earthquakes
The crustal isostatic anomaly beneath eastern Tibet and western Sichuan and its relationship with the distribution of earthquakes
复制标题
DOI：
--
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Z. Yong;Wang Qian
中科院分区：
文献类型：
--
作者：
Z. Yong;Wang Qian
川西藏东地区是青藏高原深部物质东移转向东南的通道。由于该区深部物质的强烈分异、调整和运动，强烈的构造活动和地震活动频繁。因此，在沿着北纬30°建立了一条横跨特提斯构造域和扬子克拉通的剖面。根据Airy均衡理论计算了该区地壳均衡理论厚度，并与主动和被动地震测深资料的地壳厚度进行了对比，讨论了该区地壳均衡状态。结果表明，沿该剖面沿着存在两个地壳不均衡区，即与稳定的四川盆地相比，这两个区域的地壳处于相当不均衡的状态。在此基础上，分析讨论了均衡异常与强震分布的关系。结果表明，非均衡区是强震的主要多发地带，非均衡带的陡梯度带是地震预报中值得注意的地方。
The area of west Sichuan and east Tibet is the channel where the deep materials of the Tibetan plateau flow eastward and turn to southeast. Due to the strong differentiation, adjustment and movement of the deep materials in this area, strong tectonic activities and earthquakes occur frequently here. Hence, a profile across the Tethyan tectonic domain and the Yangzi craton has been set along the 30°N latitude. And the theoretical isostatic crustal thickness has been calculated according to the Airy isostatic theory and compared with the crustal thickness obtained from both the active and passive seismic sounding data, so as to discuss the isostatic state of the area. The result reveals that there exist two non-isostatic regions along this profile, that is to say, compared with the stable Sichuan basin, the crusts of these two regions are in quite a non-isostatic state. Based on this result, we have analyzed and discussed the relationship between isostatic anomaly and the distribution of strong earthquakes. Our result suggests that the non-isostatic area is the main zone where strong earthquakes occur frequently, and the steep gradient belt of the non-isostatic zone is the place worth more attention concerning earthquake prediction.