摘要
2020年7月12日唐山古冶发生M_(S)5.1地震,对其发震断层几何形状和滑动性质,以及后续余震的应力触发进行研究,主要得到以下结论:①发震构造:基于收集的古冶震源区地震精定位结果,使用改进的模糊聚类分析方法,计算得到断层的几何形状和断层空间分布,其中断层走向为230.2°,倾角为86.2°;基于震源机制得到该地区构造应力场,并将构造应力场投影到发震断层面上,得到该地震发震断层滑动角,数值为-177.2°。②应力触发:基于经验公式,得到该地震破裂模型,其断层长为3.9 m,宽为4.4 m,断层滑动量为1.9 cm;基于破裂模型和PSGRN/PSCMP软件包,计算该地震对M_(S)4.3余震和其他余震的应力触发,结果显示:不同深度上的主震对余震的应力触发不同,其中,主震在12 km深度上对余震的应力触发比例最高;在计算主震对M_(S)4.3余震的应力触发时,发现其位于主震引起的库仑应力变化为正的区域,表明该地震受到M_(S)5.1地震的触发作用。本研究结果对研究和了解唐山震源区地震断层的发震构造以及地震危险性具有一定意义。
On July 12nd,2020,the M_(S)5.1 earthquake occurred in Guye,Tangshan.This paper primarily investigates the fault geometry and slip properties,as well as the stress triggering of subsequent after shocks.The main conclusions are as follows:①Regarding the seismogenic structure,based on the precise seismic relocation results of the Guye earthquake,the improved fuzzy clustering analysis method was used to calculate the fault geometry and spatial distribution of the fault.The strike of the fault is 230.2°,and the dip angle is 86.2°.Based on the focal mechanism,the tectonic stress field of the region was obtained,and project the tectonic stress field onto the seismogenic fault plane,the slip angle of the fault was-177.2°.②In terms of stress triggering,thepaper derives the earthquake rupture model based on empirical formulas,the fault length is 3.9 m and width is 4.4 m,and a fault slip is 0.02 m;Based on the rupture model and PSGRN/PSCMP software packages,we calculated the earthquake stress triggering on M_(S)4.3 aftershock and other aftershocks.The results shows that the triggering by the main shock on aftershocks varies at different depths,with the highest proportion of stress triggering on aftershocks at the depth of 12 km.When calculating the triggering of the M_(S)5.1 earthquake on the M_(S)4.3 earthquake,we found that the magnitude 4.3 earthquake was located in the area where the Coulomb stress change caused by the M_(S)5.1 earthquake was positive,indicating that the earthquake was triggered by the M_(S)5.1 event.The research results of this paper have certain significance for studying and understanding the seismogenic structure and seismic risk in Tangshan area.
作者
靳志同
周明月
白梓明
刘佳璐
余海琳
JIN Zhitong;ZHOU Mingyue;BAI Ziming;LIU Jialu;YU Hailin(Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,China;Hongshan Seismological Observatory of Hebei Earthquake Agency,Xingtai 054000,China)
出处
《地震地磁观测与研究》
2024年第6期2-13,共12页
Seismological and Geomagnetic Observation and Research
基金
国家自然科学基金(项目编号:42174074,41674055)。
