基于P波位移增长特征的矩震级时域估算方法  

Time-domain moment magnitude estimation based on P wave displacement growth characteristics

作　　者：王江[1,2] 马强 陶冬旺[1,2] 解全才 薛韬 WANG Jiang;MA Qiang;TAO Dongwang;XIE Quancai;XUE Tao(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)

机构地区：[1]中国地震局工程力学研究所地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [2]地震灾害防治应急管理部重点实验室,黑龙江哈尔滨150080

出　　处：《自然灾害学报》2023年第5期21-32,共12页Journal of Natural Disasters

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(2021B08);黑龙江省自然科学基金资助项目(LH2022E119)。

摘　　要：震时震级估计是地震预警(EEW)系统的关键环节之一,通过有限记录的幅值和频率成分与震级的统计关系实现震源规模快速估计。然而统计方法未采用客观表征地震能量的物理量,对震源破裂传播过程考虑不足,不能直接量化地震矩。在地震场景应用中,EEW系统存在震级估算结果离散,大震震级低估等问题。为实时量化地震破裂能量,推导了中、小地震P波位移波形参数(位移峰值P_(d)和峰值时刻t_(pd))与地震矩的理论关系,并通过日本地震的震源时间函数库验证。采用日本K-net台网记录,分析近场强震动记录P波位移增长特征,尝试从P_(d)曲线中提取特征参数P_(d)和t_(pd),构建预测矩震级的新参数Pdt。离线数据的矩震级估算结果表明,构造参数Pdt能够可靠地预测地震的矩震级,优于经典预警震级参数P_(d)。该时域矩震级估算方法为EEW系统的地震能量评估提供了新的思路。Real-time magnitude estimation is one of the key aspects of the earthquake early warning(EEW)systems,which achieves the rapid estimation of the earthquake source size through the statistical relationship between the amplitude and frequency components of the limited waveforms and earthquake magnitude.However,the statistical methods do not adopt the physical quantity that objectively characterize the earthquake energy and does not sufficiently consider the source rupture propagation process,so it can not directly quantify the earthquake moments.In seismic scenario applications,the EEW system suffers from discrete magnitude estimation results and underestimation of the magnitude of large earthquakes.In order to quantify the earthquake rupture energy in real time,the paper derives the theoretical relationship between the P-wave displacement waveform parameters(peak displacement P_(d)and peak time t_(pd))of small and moderate earthquakes and seismic moments,and verifies it by the library of source time functions for Japanese earthquakes.Using the records of the K-net network in Japan,we analyze the P-wave displacement growth characteristics of the near-field strong motion records,and try to extract the characteristic parameters P_(d)and t_(pd)from the P_(d)curves to construct a new parameter Pdt for predicting the moment magnitude.The results of the moment magnitude estimation from off-line data show that the constructed parameter Pdt can reliably predict the moment magnitude of an earthquake,which is better than the classical parameter P_(d).This real-time moment magnitude estimation method provides a new idea for the seismic energy evaluation of EEW system.

关 键 词：地震预警 矩震级估计 P波位移 时域方法 震源时间函数 

分 类 号：P315.9[天文地球—地震学]