中国青藏高原M≥6.0地震的辐射能量测定  

Determination of the radiated seismic energy for M≥6.0 earthquakes in the Qinghai-Xizang Plateau

作　　者：孔韩东 刘瑞丰[1] 边银菊[1] 刘伟 Kong Handong;Liu Ruifeng;Bian Yinju;Liu Wei(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;The Second Monitoring and Application Center,China Earthquake Administration,Xi’an 710054,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国地震局第二监测中心,西安710054

出　　处：《地震学报》2024年第3期442-457,共16页Acta Seismologica Sinica

基　　金：中国地震局地球物理研究所基本科研业务费专项(DQJB22B18)资助。

摘　　要：地震辐射能量主要由高频体波携带,与震源动态特征直接相关,能够有效地弥补地震矩和矩震级对震源动态过程和高频成分描述的不足,为地震应急和灾害评估提供更为全面的参考。本文使用自主研发的地震辐射能量测定软件测定了中国青藏高原自1990年以来M≥6.0浅源地震的地震辐射能量,并初步分析了中国青藏高原地区浅源地震的能量释放规律。研究结果表明:(1)利用该软件测定的中国青藏高原地区的34例浅源地震所得的测定结果稳定可靠。在一般情况下,地震的矩震级M_(W)与能量震级M_(e)并不相等,为了更全面地评估地震动效应,不仅需要考虑地震断层错动的静态特征,还需要考虑震源的动态特性。因此,在表示震源特性时,矩震级M_(W)和能量震级M_(e)各有特点,优势互补。(2)改则地震和尼玛地震的能量震级分别为6.47和6.00,地震辐射能量分别为1.26×10^(14) J和0.25×10^(14) J。两次震源位置相近、矩震级相同的地震,所释放的能量相差5倍之多。为了探究改则地震与尼玛地震能量释放差异的原因,我们通过S变换对两次地震的波形进行了时频分析。结果表明,震源动态过程的不同导致了地震辐射能量释放过程的差异。因此能量震级和地震辐射能量等动态震源参数比矩震级更适合描述震源的动态过程和地震的潜在破坏性。(3)结合地震矩资料得到中国青藏高原地区浅源地震的平均能矩比为1.9×10^(-5),是全球浅源地震平均能矩比的1.6倍。能矩比的大小与震源机制有关,走滑型地震的平均能矩比高于倾滑型地震。(4)中国青藏高原浅源地震的能矩比分布存在区域特征,东部和西部平均能矩比分别为2.25×10^(-5)和1.62×10^(-5),东部明显高于西部。能矩比的区域性差异与地质构造背景有关,地震辐射能量能够反映该地区的地质构造状态。同一区域内地震的能矩比也存在差别,中国青�This study focuses on the radiated seismic energy of earthquakes with a magnitude of 6.0 or greater in Qinghai-Xizang Plateau of China,a region known for its seismic activity due to its unique tectonic setting.Radiated seismic energy,predominantly carried by high-frequency body waves,is a critical parameter that reflects the dynamic rupture process of an earthquake and complements the static characteristics described by seismic moment and moment magnitude.The accurate measurement of the radiated seismic energy is essential for a comprehensive understanding of earthquake dynamics,emergency response,and disaster assessment.The research utilized self-developed software to measure the radiated seismic energy of shallow earthquakes with a moment magnitude(M_W) above 6.0 that occurred in Qinghai-Xizang Plateau since 1990.The study involved 34 earthquakes and aimed to analyze the energy release patterns in the region.It will help us to enhance our understanding of energy release patterns and their implications for seismic hazard assessment.Introduction The Qinghai-Xizang Plateau,often referred to as the “Roof of the World”,is not only a significant geographical feature but also a critical area for the study of seismic activity due to its location at the convergence of multiple tectonic plates.The region's seismicity is influenced by the ongoing collision and compression of the Indian Plate with the Eurasian Plate,leading to a high potentiality for earthquake occurrences.The accurate measurement and analysis of radiated seismic energy are crucial for the potential hazards assessment posed by earthquakes,emergency response strategies forewarning,and guidance on the development of resilient infrastructure.Methodology The study employed a self-developed software to measure the radiated seismic energy of shallow earthquakes with a moment magnitude(M_(W)) above 6.0.The software operates on the principles of point-source modeling and integrates the seismic moment rate spectrum over a specific frequency range to calculate t

关 键 词：中国青藏高原 地震辐射能量 能量震级 能矩比 矩震级 动态震源参数 

分 类 号：P315.63[天文地球—地震学]