Gravity pattern in southeast margin of Tibetan Plateau and its implications to tectonics and large earthquakes
Gravity pattern in southeast margin of Tibetan Plateau and its implications to tectonics and large earthquakes
复制标题
青藏高原东南缘重力格局及其对构造和大地震的意义
DOI：
10.26464/epp2019044
复制
发表时间：
2019-09
影响因子：
2.9
通讯作者：
Yuan Gao
中科院分区：
文献类型：
--
作者：
Yue Wu;Yuan Gao
青藏高原东南缘活动断裂发育，龙门山、鲜水河、安宁河三条大型活动断裂带汇合成“Y”字形。强烈的地壳形变和复杂的断层分布伴随着强烈的地震活动。本文利用小波变换对青藏高原东南缘的一个多尺度重力异常进行了研究，发现重力场的模式与研究区的断裂系统密切相关。通过对布格重力异常不同阶次特征的分析表明，东喜马拉雅构造结在向北运动的过程中产生了强烈的东推作用，导致地壳自西向东缩短，青藏高原迅速隆升。松潘-甘孜地块和川滇地块被迫向南、向东侧向滑动挤压。1970 - 2018年7次大地震的分布反映了大地震与重力异常特征的关系。对比几次地震的构造背景，发现大地震多发生在重力异常高梯度带，一般与块体边界带相对应。我们推断，大地震主要发生在上地壳的高布格重力异常区，而低布格重力异常则包括下地壳和上地幔。
There are many active faults in the southeast margin of Tibetan Plateau, where three large active faults zones, the Longmenshan, Xianshuihe and Anninghe, merge to form a "Y" shape. Strong crustal deformation and a complicated fault distribution accompany strong earthquake activity in this zone. In this paper, we investigate a multi-scale gravity anomaly in the southeastern margin of the Tibetan Plateau using the wavelet transform; we find that the pattern of the gravity field is closely related to the fault system in the study area. Analyzing the characteristics of this Bouguer gravity anomaly at different orders indicates that the eastern Himalayan syntaxis has produced a strong eastward push during its northward movement, resulting in a shortening of the crust from west to east and a rapid uplift of the Tibetan Plateau. The Songpan–Garze and Sichuan–Yunnan blocks have been forced to slip and extrude southward and eastward laterally. The distributions of seven large earthquakes from 1970 to 2018 reflects the relationship between large earthquakes and characteristics of the gravity anomaly. Comparing the tectonic backgrounds of several earthquakes reveals that the large earthquakes occur usually in the high gravity anomaly gradient zone, which corresponds in general to the boundary zones of the blocks. We infer that large earthquakes occur primarily in high Bouguer gravity anomaly zones in the upper crust, while low Bouguer gravity anomalies encompass the lower crust and the uppermost mantle.
登录
查看更多内容
DOI：
10.1111/j.1755-6724.2009.00093.x
发表时间：
2009-08
期刊：
Acta Geologica Sinica ‐ English Edition
影响因子：
--
作者：
Yueqiao Zhang;S. Dong;Nong Yang
通讯作者：
Yueqiao Zhang;S. Dong;Nong Yang
DOI：
--
发表时间：
2010
期刊：
Chinese Journal of Geophysics
影响因子：
--
作者：
Z. Yong;Wang Qian
通讯作者：
Z. Yong;Wang Qian
基于GPS密集观测数据的川滇地块南部当代地壳构造运动
影响因子：
2.9
作者：
Honglin Jin;Yuan Gao;Xiaoning Su;Guangyu Fu
通讯作者：
Guangyu Fu
DOI：
10.1360/03yd0518
发表时间：
2004-06
期刊：
Science in China Series D: Earth Sciences
影响因子：
--
作者：
Zhongjie Zhang;J. Teng;Yingkang Li;S. Klemperer;Li‐Qiang Yang
通讯作者：
Zhongjie Zhang;J. Teng;Yingkang Li;S. Klemperer;Li‐Qiang Yang
DOI：
10.1130/0-8137-2327-2.1
发表时间：
1998
期刊：
--
影响因子：
--
作者：
E. Wang;B. Burchfiel;L. Royden;Liangzhong. Chen;Jishen Chen;Wenxin Li;Zhiliang Chen
通讯作者：
E. Wang;B. Burchfiel;L. Royden;Liangzhong. Chen;Jishen Chen;Wenxin Li;Zhiliang Chen