四川长宁MS6.0地震区域构造应力场特征分析

Characteristics of the Regional Tectonic Stress Field of the Changning MS6.0 Earthquake, Sichuan Province

摘要:

2019年6月17日在四川宜宾市长宁县（28.34°N，104.90°E）发生M_S6.0地震，余震发育。本文利用区域测震台网的地震观测数据基于CAP方法计算了28°~29°N，104°~105°E范围内的14个M_S>3.0以上地震的震源机制解，结合全球矩心矩张量目录和部分前人研究结果中该区域的共27个震源机制解数据，应用MSATSI软件反演了研究区域的应力场。将研究区域按0.1°×0.1°划分成25个应力网格，最终得到9个网格的应力分布结果，大多数应力场方向稳定，根据主震所在应力网格点得到主震的断层类型为主逆冲型。本文研究成果为四川长宁地区的孕震机理、活动构造以及地震趋势判定提供了可靠的参考依据。

Abstract:

On June 17, 2019, an M_S6.0 earthquake occurred in Changning County, Yibin City, Sichuan Province (28.34°N, 104.90°E), China, followed by aftershocks.Seismic observation data from the regional seismic network were used to calculate the focal mechanism solutions of 14 M_S>3.0 earthquakes in the range of 28°-29°N, 104°-105°E, based on the CAP method.Combined with data from 27 focal mechanism solutions of the study area from previous research results, the stress field of the study area was inverted using MSATSI software.After gridding the study area as 0.1°×0.1°, the distribution of 25 stress fields was obtained.Most of the stress fields were stable.The fault type of the mainshock was mainly a thrust earthquake according to the stress grid where the mainshock was located.Results of this paper can provide a reliable reference for seismogenic mechanisms, active structure, and the determination of seismic tendencies in the Changning area of Sichuan Province.