Preliminary study of the tectonic structure and seismogenic environment of the M4.7 Feidong earthquake sequence on September 18, 2024 in Hefei

作者：NI Hong-yu, Junlun Li, Huajian Yao, Xianliang Huang, Lingli Li, Dongrui Zhou, Xiaoli Wang, Shuyuan Yu, Yajun Lu, J. Yu, Haigang Zheng, Guili Zhou, Hanwen Zou, Wen Yang, Ming Zhang, Guoyi Chen, Ye Lin, Guanling Peng, Zefeng Li, Haipeng Li · 发表于：地震学报：英文版 · 年份：2025 · DOI：10.1016/j.eqs.2024.11.001 · 被引用次数：4 · 研究领域：earthquake and tectonic studies、Earthquake Detection and Analysis、Seismic Waves and Analysis

At 20:08, on September 18, 2024, an M 4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei, Anhui Province. This earthquake is the largest event in the modern history of Hefei, which caused substantial social impact. To reveal the seismogenic structure of the M 4.7 Feidong earthquake sequence and assess seismic risks, we use data from both the permanent seismic network and a temporary dense nodal array deployed in the epicentral region prior to the mainshock for: (1) accurate location of the earthquake sequence and determination of the focal mechanisms; (2) obtaining the spatiotemporal distribution, b -value, and half-day occurrence frequency of the earthquake sequence. The Sentinel-1 satellite data are used to analyze the coseismic displacement. Additionally, velocity models from regional tomography and local high-resolution 2D active- and passive-source surveys across the Tanlu fault zone in the epicentral area are also used to reveal the detailed geometry of the seismogenic fault. The results indicate: (1) the M 4.7 Feidong earthquake sequence is concentrated around 10.5 km in depth along a NW-dipping, subvertical fault which trends NE and is approximately 5 km in length; the focal mechanism solution also reveals that the fault hosting the mainshock is a subvertical strike-slip fault, driven by the regional compressional stress in ENE-WSW; the coseismic horizontal displacement on the surface caused by the M 4.7 mainshock has a maximum value clo...