摘要
震源特征可通过震源参数量化,震后快速测定震源参数,对于研究区域构造特征、地震的震源性质和孕育演化过程、开展震害评估和地震应急响应都具有重要意义.本研究采用区域地震台网和全球地震台网提供的宽频带波形资料,使用近震全波形反演方法得到了2022年1月8日青海门源M_(S)6.9地震的地震矩、矩震级和震源机制解等静态震源参数,并测定了地震辐射能量、能量震级和破裂持续时间等动态震源参数.结果显示:(1)本次地震为一次高倾角的走滑型地震,震源机制解节面I走向194°、倾角87°、滑动角175°,节面II走向285°、倾角85°、滑动角3°,地震矩为8.5×10^(18)N·m,转化成矩震级为6.6,矩心深度为3 km.结合动态震源参数,可确定节面II为地震断层面;(2)地震辐射能量为4.3×10^(14)J,转化成能量震级为6.8,高于矩震级;(3)地震呈现双侧破裂特征,破裂持续时间为11 s;(4)能矩比为5.1×10^(-5),视应力为1.53 MPa,应力降为6.58 MPa,描述断层破裂复杂度的辐射能量增强因子为34;(5)综合本文结果,可认为门源地震属于一次断层倾角较高、能量释放效率偏高的走滑型地震.与同样震级的地震相比,这样的地震一般会造成比较严重的灾害.
The characteristics of an earthquake can be quantified by source parameters.After an earthquake,it is important to determine the source parameters quickly to study regional tectonic characteristics,the nature of earthquake sources,and the process of earthquake incubation and evolution,and to assess earthquake damage and respond to earthquake emergencies.In this study,the seismic moment and focal mechanism of M_(S)6.9 Qinghai Menyuan earthquake are inverted using the time-domain full moment tensor inversion method,and the corrected radiated seismic energy,energy magnitude,and rupture duration are determined according to the waveforms recorded at the regional and global seismic stations.The results show that(1)The Menyuan earthquake is a strike-slip earthquake with its strike/dip/rake 194°/87/175°and 285°/85°/3°for nodal planes I and II,respectively.The moment magnitude M_(W)is 6.6with an optimal source depth of 3km.A combination of the dynamic parameters of the earthquake source indicates that nodal plane II is the fault plane of the earthquake;(2)The radiated seismic energy E_(R)is computed to be 4.3×10^(14) J,the corresponding Meis 6.8,which is significantly greater than MW;(3)The earthquake shows bilateral rupture characteristics,and the rupture duration is 11s;(4)Considering all above parameters together,we can obtain values of the energy-to-moment ratio E_(R)/M_(0)is 5.1×10^(-5),the apparent stress,stress drop and the radiated seismic energy enhancement factor that describes the rupture complexity is 1.53MPa,6.58MPa and 34,respectively;(5)Combining the static and dynamic source parameters of this earthquake,it can be concluded that the Menyuan earthquake is a strike-slip type earthquake with a large dip of the fault plane and high energy release efficiency.In general,such earthquakes cause more damage than earthquakes of the same magnitude.
作者
王子博
刘瑞丰
李赞
胡岩松
孔韩东
WANG ZiBo;LIU RuiFeng;LI Zan;HU YanSong;KONG HanDong(Institute of Geophysics,China Earthquake Administration,Beijing100081,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第6期2420-2430,共11页
Chinese Journal of Geophysics
基金
中国地震局地球物理研究所基本科研业务专项(DQJB22B18,DQJB21X28)资助。
关键词
门源MS6.9地震
震源参数
震源机制
震源特征
Menyuan M_(S)6.9 earthquake
Seismic parameter
Focal mechanism
Seismic characteristic
