摘要
为研究2024年新疆阿克苏地区乌什县M S7.1大震对周边区域应力的影响,基于美国地质调查局(USGS)给出的主震破裂模型,计算此次地震对周边地区产生的同震位移场及应变场,结果发现:体应变在震源西北侧呈现拉张,东南侧呈现挤压;面应变的分布与体应变的形态基本相似。为研究该地震对余震的触发情况,首先需要确定接收断层的断层面参数,对中国地震台网发布的2024年1月23日到2024年4月10日的余震震源机制节面聚类分析,得到两簇结果,选择标准差较小的二簇节面进行平均,得到走向为243.91°,倾角为64.97°;将乌什地震震源区的构造应力场投影到该发震断层上,得到滑动角为61.02°。将这些参数作为余震接收断层的断层面参数,同样基于USGS给出的主震断层破裂模型,计算主震产生的静态库仑应力,研究发现:区内库仑应力均超过0.01 MPa阈值,且库仑破裂应力最大值达0.3 MPa,大多数余震处于库仑应力变化的高值区;表明主震产生的静态库仑应力促进了余震的发生。为研究该地震发生对周围断层的影响,根据前人给出的周边断层的几何和滑动特性,计算在周边断裂上沿滑动方向上的库仑破裂应力变化,研究发现:本次地震对迈丹—沙依拉姆断裂库仑应力最大增加量达到0.22 MPa,喀拉铁克断裂、衣木干他乌断裂、塔塔埃尔塔格断裂、奥兹格尔他乌断裂、柯坪断裂的库仑应力变化并不明显,迈丹—沙依拉姆断裂库仑应力增加最大,应注意该断层的地震活动性。
To assess the stress impact of the 2024 M S7.1 earthquake in Wushi County,Aksu Prefecture,Xinjiang,on the surrounding areas,this study utilized the mainshock rupture model proposed by the United States Geological Survey(USGS).The coseismic displacement and strain fields generated by the earthquake in the surrounding areas were calculated on this model.The volume strain was found to manifest as tension on the northwest side of the source and compression on the southeast side.The distribution of the areal strain closely mirrored the morphology of the volume strain.To study the triggering of aftershocks by the M S7.1 mainshock,the fault plane parameters of the receiving fault were determined.The focal mechanisms of aftershocks from January 23 to April 10,2024,released by the China Earthquake Networks Center,were analyzed,resulting in two clusters of nodal planes.The second cluster,which had a small standard deviation,was selected,revealing an average strike and dip angle of 243.91°and 64.97°,respectively.The tectonic stress field of the earthquake source area was projected onto the seismogenic fault,resulting in a slip angle of 61.02°.Utilizing the mainshock rupture model proposed by USGS,the static Coulomb failure stress(CFS)generated by the mainshock was calculated using the determined parameters.The CFS in the study region exceeded the threshold of 0.01 MPa,with the maximum value reaching 0.3 MPa.Most aftershocks were located in high-value areas of CFS,indicating that the CFS generated by the mainshock promoted aftershock occurrence.To study the impact of the M S7.1 earthquake on surrounding faults,the CFS changes along the sliding direction of the faults were calculated based on their geometric and sliding characteristics.The results showed a maximum increase in CFS of 0.22 MPa on the Maidan-Shayiram fault,highlighting the need for increased attention to seismic activity in this area in the future.Conversely,the CFS changes on the Karatek fault,Yimugantau fault,Tataertag fault,Ozgeltau fault,and Keping fault were not significant.
作者
宋泽尧
万永革
关兆萱
顾培苑
王润妍
SONG Zeyao;WAN Yongge;GUAN Zhaoxuan;GU Peiyuan;WANG Runyan(Institute of Disaster Prevention,Sanhe 065201,Hebei,China;Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China;Hebei Hongshan Giant Thick Sediments and Earthquake Disasters National Field Scientific Observation and Research Station,Longyao 055350,Hebei,China)
出处
《地震工程学报》
CSCD
北大核心
2024年第4期982-991,共10页
China Earthquake Engineering Journal
基金
国家自然科学基金(42174074,41674055,42364005)
中央高校科研业务费专项(ZY20215117)。
