2025年西藏定日6.8级地震本地次声波观测与特征分析  

Observation and features of local infrasonic waves associated with 2025 Dingri 6.8-magnitude earthquake in Xizang

作　　者：郭泉 杨选辉 木英 GUO Quan;YANG Xuanhui;MU Ying(National Institute of Natural Hazards,Ministry of Emergency Management,Beijing 100085,China;Lijiang Earthquake Agency,Lijiang 674199,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,北京100085 [2]丽江市地震局,云南丽江674199

出　　处：《安全与环境工程》2025年第2期14-19,30,共7页Safety and Environmental Engineering

基　　金：国家自然科学基金青年科学基金项目(11704346);中央级公益性科研院所基本科研业务专项项目(ZDJ2019-23)。

摘　　要：2025年西藏定日6.8级地震触发的本地次声波信号被滇西北丽江和宁蒗次声台阵(震中距分别为1271 km和1303 km)同步观测。通过对比2地本地次声波信号特征差异,结合浅层钻孔地质剖面与断裂带分布,揭示浅表地层结构对地震能量耦合机制的影响,并为区域地质结构分析提供新方法。结果显示:2地本地次声信号特征存在显著的差异,丽江台阵信号传播时间(440 s)较宁蒗台阵(494 s)缩短54 s,声压幅度(2.1 Pa)为宁蒗台阵(0.7 Pa)的3倍;丽江台阵信号中心频率范围(0.5~2.0 Hz)宽于宁蒗台阵(0.4~1.2 Hz),且1~3 Hz频段能量占比更高;结合地质剖面与Wigner-Ville分布分析,丽江盆地浅表松散地层通过共振效应放大了地震瑞利波1~3 Hz频段成分,增强了本地次声波耦合效率;宁蒗台阵附近高刚度地表介质及丽江-小金河断裂带的散射作用导致高频衰减和波速降低。该研究显示了地震本地次声波信号特征可反映浅表地层地质属性,通过建立地震危险区域次声观测网络,能够为地震波能量耦合机制和区域地质结构探测提供新的技术手段。The local infrasound signals generated by 20256.8-magnitude Dingri earthquake in Xizang were synchronously monitored by infrasound arrays in Lijiang and Ninglang,northwestern Yunnan,with epicentral distances of 1271 km and 1303 km,respectively.This study aims to reveal the influence of shallow subsurface geological structures on seismic energy coupling mechanisms by comparing the differences in local infrasound signal features between two sites,combined with shallow geological profiles and fault zone distribution,thereby providing a novel method for regional geological structure analysis.Significant differences of signal features were found:the propagation time of signals of the Lijiang array(440 s)is 54 s shorter than that of Ninglang(494 s),with a sound pressure amplitude of 2.1 Pa,three times higher than Ninglang’s 0.7 Pa;the central frequency range of Lijiang signals(0.5-2.0 Hz)is broader than that of Ninglang(0.4-1.2 Hz),and the specturm energy in the 1-3 Hz band is higher in Lijiang;geological profiles and Wigner-Ville distribution indicate that loose surface layers in the Lijiang Basin amplify the 1-3 Hz components of seismic Rayleigh waves through resonance effects,enhancing local infrasound coupling efficiency;in contrast,the higher stiffness of near-surface and scattering effects from the Lijiang-Xiaojinhe fault zone near the Ninglang array attenuate high-frequency components and reduce wave velocity.This study suggests that local infrasound signal characteristics can effectively reflect shallow subsurface geological properties.The deployment of infrasound observation in seismic hazard zones offers a new technical approach for investigating seismic energy coupling mechanisms and probing regional geological structures.

关 键 词：定日6.8级地震 本地次声波 浅表地层 信号特征 瑞利波耦合 

分 类 号：X43[环境科学与工程—灾害防治] P315.7[天文地球—地震学]