首页|采用2021年青海玛多地震序列震源机制节面聚类确定发震断裂几何形态

采用2021年青海玛多地震序列震源机制节面聚类确定发震断裂几何形态

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
  • 维普
地震断裂带形状是活动构造和地球动力学的重要资料.2021年发生的玛多地震序列提供了丰富的震源机制资料,为统计震源机制节面并估计玛多地震发震断层面形状提供了很好机会.文章对地震的震源机制资料进行基于密度的聚类来确定断层的几何形态.首先对收集到的玛多地震序列的震源机制解进行中心解求解,从而获得更为精准的数据,然后对其进行DBSCAN方法的聚类分析,得到断层的走向为113.5°,倾角为88.2°,通过震源机制反演应力场,并将应力场投影到断层上,得到断裂带的相对剪应力和相对正应力分别为0.84和-0.79,剪应力强度较大,滑动角为-0.72°.结果表明玛多地震是发震断裂受NE-SW的挤压和NW-SE的拉张,形成了较大的剪切力,从而促使近东西的江错断裂发生左旋走滑错动所致.
Fault geometry determination by clustering nodal planes of focal mechanisms of the 2021 Maduo,Qinghai earthquake sequence
The shape of seismic fault zones is essential for the study of active tectonics and geody-namics.The Maduo earthquake sequence that occurred in 2021 provides rich focal mechanism data and a suitable opportunity for counting the nodal planes of focal mechanisms and estimating the geometry of the seismogenic fault.Herein,the seismogenic fault geometry was determined using a density-based clustering algorithm to analyze the focal mechanism data.First,the central focal mechanism of the Maduo earthquake sequence was solved to obtain accurate data.Then,the re-suits of a strike of 113.5° and a dip of 88.2° were obtained using the DBSCAN method.Finally,by inversion and projection of the stress field on the fault,the relative shear stress and relative nor-mal stress were obtained as 0.84 and-0.79,respectively,and the sliding angle was estimated as-0.72°.The results show that the Maduo earthquake was caused by the stress of northeast-southwest compression and northwest-southeast extension.Then,a large shear stress was gener-ated on the Jiangcuo fault with a nearly east-west orientation,thus causing a left-lateral strike-slip dislocation on the fault.

fault geometryfocal mechanismdensity clustering analysis of noisy data2021 Maduo earthquake sequence

沈千贺、万永革

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防灾科技学院,河北三河 065201

河北省地震动力学重点实验室,河北三河 065201

断层几何特征 震源机制 有噪声数据的密度聚类分析 2021玛多地震序列

国家自然科学基金国家自然科学基金中央高校基本科研业务费专项河北省地震动力学重点实验室开放基金

4217407441674055ZY20215117FZ212105

2024

10.20000/j.1000-0844.20220718001

地震工程学报
中国地震局兰州地震研究所,中国地震学会，清华大学，中国土木工程学会

地震工程学报

CSTPCD北大核心
影响因子：1.191
ISSN：1000-0844
年,卷(期)：2024.46(1)
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