华南地震2023，Vol.43Issue(4)：107-118,12.DOI:10.13512/j.hndz.2023.04.14
2023年2月5日三水ML4.0级矿山地震震相特征与发震构造
Seismic Phase Characteristics and Seismogenic Structure of the Sanshui ML4.0 Mining-induced Earthquake on February 5th,2023
摘要
Abstract
On February 5th,2023,an ML4.0 earthquake occurred in Sanshui,Guangdong,which was felt in Foshan,Guangzhou,Shenzhen and other areas.The feeling range is wide,and the epicenter is located in the salt mining area,so it attracts significant attention.This article collected and carefully analyzed 342 high-quality seismic records and 410 strong-motion records within a 800 km of the epicenter.Through manual analysis,a total of 967 seismic phases were identified.The statistical analysis reveals that:All station records exhibits substantial high-fre-quency components before the arrival of the Sg wave.After the Sg wave,there are 75 stations recorded short-period surface waves with periodic changes(period between 1.1-1.5 s),less burrs and regular vibration,and their dura-tion is about 5-20 s.Overall amplitude of surface waves decreases with the increase of the epicenter distance,but there is a sudden increase of several times at some stations.The apparent velocity of the maximum peak is about 2.85 km/s,which is more obvious in the vertical direction,and consistent with the characteristics of Rg surface wave.The focal depth determined by the depth phase sPn is about 3.8±0.39 km,and the revised epicentral location is:112.958 3°N,23.271 6°E.The initial motion is distributed in four quadrants,and the determined seismogenic structure is:strike 334.90°,dip angle 54.04°,and a slip angle-18.84°.The dislocation type is mainly left-later-al strike-slip,with a small amount of normal fault.Through comprehensive analysis,it is believed that this earth-quake is induced by long-term brine extraction and salt mining activities.The stress variations within the mined-out area leads to the adjustments in the stress distribution of the ore body.The stress along the F7 fault exceeded its load-bearing capacity,resulting in rupture and sliding of the hanging wall under the predominant control of region-al stress,which leads to the mining-induced earthquake closely related to the mining activity.关键词
三水地区/矿山地震/震相特征/震源定位/发震断裂Key words
Sanshui region/Mining-induced earthquake/Seismic phase characteristics/Source location/Seismogenic fault分类
天文与地球科学引用本文复制引用
杨选,马晓静..2023年2月5日三水ML4.0级矿山地震震相特征与发震构造[J].华南地震,2023,43(4):107-118,12.基金项目
广东省省级科技计划协同创新与平台环境建设重点项目(2019B020208014) （2019B020208014）
