基于有限断层识别方法(FinDer)快速计算断层破裂长度及方向  

Fast estimation of fault rupture length and direction based on FinDer method

作　　者：于伟恒 王士成[1] 周跃勇[1] 周施文 李水龙 Yu Weiheng;Wang Shicheng;Zhou Yueyong;Zhou Shiwen;Li Shuilong(Fujian Earthquake Agency,Fuzhou 350003,China)

机构地区：[1]福建省地震局,福州350003

出　　处：《地震学报》2024年第5期865-876,共12页Acta Seismologica Sinica

基　　金：国家重点研发计划项目(2018YFC1504005);国家自然科学基金(42104062)共同资助.

摘　　要：为了快速计算震后断层的破裂参数、适应场地特征和减少模板匹配的时间,对美国加州ShakeAlert地震预警系统中断层破裂参数实时测定方法FinDer方法中的台站性质判别和模板匹配两个环节进行了改进和优化,并基于我国大陆的六次M4.5—8.0地震对改进后的FinDer方法进行了验证。计算结果表明:对于4.5≤M≤5.5地震,利用FinDer方法能够快速得到断层的破裂方向和长度,但由于断层破裂长度有限,所计算的断层方向准确度不高;对于M>5.5地震,在首台触发后开始使用FinDer方法计算断层的长度和方向,计算过程持续数秒至1分钟左右,断层破裂长度和方向与野外调查结果基本一致;当地震引发多条断层破裂时,该方法只能计算一个综合的断层方向和长度。The distribution direction and rupture length of large earthquake faults will affect the prediction of the city intensity in the earthquake early warning system and the subsequent outputs in the intensity rapid reporting system,such as the intensity of cities and towns,spatial distribution maps of intensity,etc.For large earthquake catastrophes,the accurate fault location will effectively improve the comprehensive processing ability of the earthquake early warning system and the intensity rapid reporting system for major earthquakes.In 2012,Bose proposed the finite fault identification rupture detector(short for FinDer),which used image recognition and template matching techniques to calculate the rupture length and direction of large earthquakes(MW>6.0)in real time.In 2015,the FinDer method was used in the ShakeAlert system in California,USA.In 2018,Bose expanded the warning range of fault parameters and proposed the second-generation algorithm,namely FinDer 2.For earthquakes with M>2.0,the peak ground acceleration(PGA)threshold was set based on the earthquake magnitudes in FinDer 2.When a station data records exceed the set PGA threshold,the station is determined as a near-source station.By identifying the distribution range of near-source stations,the near-field area with strong ground motion is obtained,which is then matched with a pre-made template with fault direction and length.Here,the length and direction of the fault are calculated using the template with the highest matching degree.The FinDer method has been running online in California for nearly ten years,and hence it provides a good demonstration for the discrimination of major earthquake faults in the earthquake early warning system,and provides a foundation for the construction of the large earthquake early warning system in the National Seismic Intensity Rapid Reporting and Early Warning project.What is more,through the construction of the national project,the current monitoring station network provides a favorable data support for the implementa

关 键 词：FinDer方法 大震断层破裂参数 地震预警系统 国家地震烈度速报与预警工程 

分 类 号：P315.2[天文地球—地震学]