摘要
应用“先粗后细”的网格划分方案和CAP方法反演2017年12月19日辽宁海城M4.4地震震源机制解。基于震源—质心(H-C)方法快速测定其发震断层面。利用改进的DBSCAN算法自动识别海城、岫岩地区主要断层的几何参数,并结合该地区构造应力场给出它们的滑动性质。结果表明:海城M4.4地震最优质心位置为(40.4672°N,123.1494°E)。震源机制解走向288°,标准差5.80°,倾角81°,标准差5.69°,滑动角-13°,标准差5.71°,矩震级MW4.34,质心深度11 km,标准差0.38 km。联合P波初动解走向34.10°,倾角67.48°,滑动角-159.64°,及其他学者的资料得到该地震震源机制中心解为走向287.51°,倾角78.66°,滑动角-22.90°。以各机构给出的震源参数和不同震源机制进行的全部25次快速识别检验均显示震源机制解NWW走向的节面II是本次海城M4.4地震的主断层面。自动识别得到3个走滑断层和1个正断层。其中断层A和断层C分别是1975年海城MS7.3地震和1999年岫岩MS5.4地震的发震构造,断层B和断层D的参数特征也与前人的认识相符。
In this study,the focal mechanism solution of Haicheng M4.4 earthquake on December 19,2017,was determined using a“Coarse-to-Fine”meshing scheme and the CAP method.The seismogenic fault plane was rapidly identified by applying the Hypocenter-Centroid(H-C)method.Geometric parameters of major faults in the Haicheng and Xiuyan regions were automatically extracted through an improved DBSCAN algorithm,and their slip characteristics were analyzed in combination with the regional tectonic stress field.The results show that the optimal centroid location of the Haicheng M4.4 earthquake is(40.4672°N,123.1494°E).Its focal mechanism solution yields a strike of 288°(standard deviation is 5.80°),a dip of 81°(standard deviation is 5.69°),a rake of-13°(standard deviation is 5.71°),a moment magnitude MW4.34,and a centroid depth of 11 km(standard deviation is 0.38 km).Integrating the P-wave first-motion solution(strike 34.10°,dip angle 67.48°,rake-159.64°)with previous studies gives a central focal mechanism solution of strike 287.51°,dip angle 78.66°,rake-22.90°.All 25 identification tests—base on focal parameters provided by multiple institutions and diverse focal mechanisms—consistently indicate that nodal planeⅡ(NWW-striking)correspinds to the primary fault plane of the Haicheng M4.4 earthquake.Automated identification revealed three strike-slip faults and one normal fault.Faults A and C were determined as the seismogenic structures of the 1975 Haicheng MS7.3 earthquake and the 1999 Xiuyan MS5.4 earthquake,respectively,while the parametric characteristics of faults B and D align with existing knowledge from prior studies.
作者
戴盈磊
张文静
惠杨
王承伟
程应伟
DAI Yinglei;ZHANG Wenjing;HUI Yang;WANG Chengwei;CHENG Yingwei(Liaoning Earthquake Agency,Shenyang 110034,China)
出处
《华南地震》
2026年第1期33-42,共10页
South China Journal of Seismology
基金
中国地震局地震应急青年重点任务(CEA_EDEM-20250204)
中国地震局地震科技星火计划项目(XH24009YA)联合资助。
