青藏高原东北缘主要断裂带的库仑应力演化及其强震危险性  

Coulomb stress evolution and seismic hazards along major faults in the northeastern margin of the Tibetan Plateau

作　　者：龚炜程 孙云强 邱鑫鹏 王甘娇 李敏娟 阮云凯 GONG Weicheng;SUN Yunqiang;QIU Xinpeng;WANG Ganjiao;LI Minjuan;RUAN Yunkai(School of Transport and Civil Engineering,Fujian Agriculture and Forestry University,Fuzhou 350002,Fujian,China;Jiangxi Earthquake Agency,Nanchang 330096,Jiangxi,China;Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China;Gansu Earthquake Agency,Lanzhou 730000,Gansu,China)

机构地区：[1]福建农林大学交通与土木工程学院,福建福州350002 [2]江西省地震局,江西南昌330096 [3]河北省地震动力学重点实验室,河北三河065201 [4]甘肃省地震局,甘肃兰州730000

出　　处：《地震工程学报》2023年第3期585-597,共13页China Earthquake Engineering Journal

基　　金：地震数值预测联合实验室开放基金(2021LNEF03);福建省自然科学基金(2022J05039;2021J05026);河北省地震动力学重点实验室开放基金(FZ212202);甘肃省地震局地震科技发展基金项目(2022Q06)。

摘　　要：自1920年海原发生M8.5地震以来,青藏高原东北缘接连发生了1927年古浪M8.0地震、1932年昌马M7.6地震等一系列大地震,使其进入了强震活动的丛集期。为了探究青藏高原东北缘这一系列地震间的相互作用及区域地震危险性,建立青藏高原东北缘的三维Maxwell黏弹性有限元模型,模拟了区域自1920年以来17次M6.7以上地震的同震及震后库仑应力演化。结果显示:研究区自1920年海原M8.5大地震之后,后续的16次地震中,有13次地震发生在库仑应力变化为正的区域,说明了地震间的相互作用可能是导致区域地震丛集的主要原因之一。系列地震发生后,阿尔金断裂、柴达木盆地断裂西段、东昆仑断裂中段、鄂拉山断裂北段、共和盆地断裂南段、日月山断裂南段、庄浪河断裂、礼县—罗家堡断裂、成县盆地断裂西段、文县断裂西段、龙首山断裂南段、六盘山断裂东段、西秦岭北缘断裂东段、海原断裂西段和祁连断裂东段位于库仑应力变化为正的区域,且大部分断裂或断裂段的累积库仑应力变化超过了0.01 MPa,它们未来的地震危险性较高。The northeastern margin of the Tibetan Plateau has been struck by a series of large earthquakes since the Haiyuan M 8.5 earthquake in 1920,including the Gulang M 8.0 earthquake in 1927 and the Changma M 7.6 earthquake in 1932.The region has entered a cluster period of intense seismic activity.A 3D Maxwell viscoelastic finite element model was established to simulate the coseismic and postearthquake Coulomb stress evolution of 17 earthquakes above M 6.7 in the study region since 1920 to investigate the correlation between these earthquakes and the regional seismic hazards in the northeastern margin of the Tibetan Plateau.Results indicate that after the 1920 Haiyuan M 8.5 earthquake,13 of the 16 subsequent earthquakes occurred in regions with positive Coulomb stress change.This finding implies that the interaction between earthquakes may be one of the primary reasons for regional earthquake clustering.After the sequence of 17 earthquakes,the following faults are observed to be located in areas with positive Coulomb stress:Altyn Tagh fault,western Qaidam Basin fault,middle section of east Kunlun fault,northern Elashan fault,southern Gonghe Basin fault,southern Riyueshan fault,Zhuanglanghe fault,Lixian-Luojiapu fault,western Chengxian Basin fault,western Wenxian fault,southern Longhoushan fault,eastern Liupanshan fault,eastern segment of the north margin of western Qinling fault,western Haiyuan fault,and eastern Qilian fault.The cumulative Coulomb stress changes in these faults are greater than 0.01 MPa,indicating a significant risk of future earthquakes.

关 键 词：库仑应力变化 三维黏弹性有限元模型 青藏高原东北缘 地震危险性 

分 类 号：P319[天文地球—固体地球物理学]