摘要
采用"虚拟断层法"给出了地震动衰减关系中震中距和断层源距转换关系。首先,根据已有资料利用经验公式确定虚拟有限断层破裂参数(L,W,Ф,δ,Z_(TOR),hypX,hypY),针对断层走向Ф没有经验公式可用的情况,给出了不同时间尺度下的断层走向确定方案。然后,利用上述7个破裂参数,联合震中距R_(EPI)和场点震中方位角θ,或者震中经纬度LL_(EPI)和场点经纬度LL_(SITE),计算4个断层源距(R_(JB),R_(RUP),R_X,R_(Y0)),无需获取有限断层模型端点经纬度。在此基础上,初步对比了震中距R_(EPI)和断层源距(R_(JB),R_(RUP))的差异及其对PGA的影响,总体上存在R_(EPI)≥R_(JB)和R_(EPI)≤R_(RUP),R_(EPI)产生的PGA介于R_(RUP)和R_(JB)之间,距离差异和PGA差异都随震级增加而增大,随距离增加而缩小最后趋于一致。本文方案可以较好的处理震中距和断层源距引起的地震动差异问题,在地震动预测图ShakeMap制作、核电等重大工程地震安全性评价和新的水工建筑设定地震反应谱确定方面具有一定应用价值。
In this paper,conversion equations of point-source epicentral distance and fault-source distances in seismic attenuation relation are derived using "Virtual Fault Method". First of all,virtual finite fault rupture parameters( L,W,Ф,δ,ZTOR,hypX,hypY) are determinated according to the available data using the empirical formulae. In view of the fact that no empirical formula is available for the fault strike direction Ф,this paper presents a scheme for determining the fault strike direction in different time scales. Then,four source-to-site distance measrues( RJB,RRUP,RX,RY0) were calculated by using the above seven rupture parameters,combined with epicentral distance REPI and epicenter-to-site azimuth θ,or epicentral latitude and longitude LLEPIand site latitude and longitude LLSITE,without obtaining the latitude and longitude of finite fault endpoint. Based on the above formulae,the differences between the point-source epicentral distance( REPI) and the fault-source distances( RJB,RRUP) and its effect on the PGA are compared. In general,there are REPI≥RJBand REPI≤RRUP. The PGA generated by REPIis between RRUPand RJB. The difference of distance and PGA gradually increase with the increase of magnitude,and decrease with the increase of distance. To some extent,the problem of ground motion caused by epicentral distance and fault source distance can be solved. It has a certain application in ShakeMap production,seismic safety evaluation of major projects such as nuclear power and the determination of design response spectrum of hydraulic struc-tures based on scenario earthquake.
作者
张效亮
张郁山
吴昊
ZHANG Xiaoliang;ZHANG Yushan;WU Hao(China Earthquake Disaster Prevention Center, Beijing 100029, China)
出处
《地震工程与工程振动》
CSCD
北大核心
2018年第1期178-189,共12页
Earthquake Engineering and Engineering Dynamics
基金
地震行业专项(201408020)
中国地震灾害防御中心主任基金项目(201704)
地震科技星火计划项目(XH17052)~~
关键词
衰减关系
距离转换
断层投影距
震中距
断层距
NGA GMPE
distance conversion
epicentral distance R EPI
Joyner-Boore distance R JB
source-to-site distance
