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《地震研究》[ISSN:1000-0666/CN:53-1062/P]

卷:

43

期数:

2020年04期

页码:

658-665

栏目:

出版日期:

2020-09-17

文章信息/Info

Title:

Characteristics of Recent Crustal Movement and Seismicity in the Northern Section of the North-South Seismic Belt

作者:

刘 雷; 蒋锋云; 朱良玉

(中国地震局第二监测中心,陕西 西安 710054)

Author(s):

LIU Lei; JIANG Fengyun; ZHU Liangyu

(The Second Monitoring and Application Center,China Earthquake Administration,Xi'an 710054,Shannxi,China)

关键词:

南北地震带北段;  应变率场;  GPS速度场;  地震危险性

Keywords:

the northern section of the North-south Seismic Belt;  strain rate field;  GPS velocity field;  seismic risk

分类号:

P315.725

DOI:

-

摘要:

利用1991—2015年GPS数据,研究南北地震带北段现今地壳水平速度场特征,根据区域地壳主应变率、面膨胀率及最大剪应变率的空间变化以及小震分布特征,对研究区主要断层的活动性及地震危险性进行综合分析。结果表明:①区域主应变率和最大剪应变高值区分布在海原断裂弧形构造带附近,香山—天景山断裂和六盘山断裂中南段应变率较低,结合历史地震及离逝时间,认为其可能处于孕震晚期; ②海原断裂现今左旋走滑速率为(4±0.5)mm/a,香山—天景山断裂、烟筒山断裂和牛首山断裂活动性较弱,总体显示为逆冲兼走滑的性质; ③震源深度剖面显示老虎山断裂、海原断裂南东段小震分布较密集而均匀,海原断裂北西段小震较少,香山—天景山东南段存在一个小震稀疏段,断层可能已经闭锁,未来应重点关注。

Abstract:

Using the GPS velocity field during 1991 and 2015,we describe the characteristics of the current crustal horizontal movement of the northern section of the North-South Seismic Belt.We investigated the tectonic dynamics and seismic hazard in the northern section of the North-South Seismic Belt by analyzing the spatial distribution characteristics of the principal strain rate,surface expansion rate,maximum shear strain rate,and small earthquakes.And we also analyzed the activity and seismic risk of main faults in the northern section of the North-South Seismic Belt.The results show that:①The high main strain rate and the high maximum shear strain rate are distributed near the Haiyuan fault tectonic belt,while the Xiangshan-Tianjingshan fault and the middle-southern segment of the Liupanshan fault have lower strain rate.Combined with the historical earthquake and the elapsed time,we deduced that Xiangshan-Tianjingshan fault and the Liupanshan fault may be in the Late phase of strong earthquake preparation; ②Therecent strike-slip rate of the Haiyuan fault is(4±0.5)mm/a.And the seismic activity of the Xiangshan-Tianjingshan fault,the Yantongshan fault and the Niushoushan fault was weak,these faults are generally characterized by thrust and strike-slip; ③The seismic depth profile shows that the distribution of earthquakes in the Laohushan fault and the south-eastern section of the Haiyuan fault is relatively dense and uniform,while few earthquakes are distributed in the north-western section of the Haiyuan fault.There is a sparse section of earthquakes in the south-eastern section of the Xiangshan-Tianjingshan fault,and the fault may have been locked which should be paid more attention to in the future.

参考文献/References:

-

备注/Memo

备注/Memo:

收稿日期:2019-07-19
基金项目:中国地震局震情跟踪项目(2020010205,2020020203)联合资助.

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更新日期/Last Update: 2020-09-17