汶川地震前多圈层短—临遥感异常回顾及其时空关联性

地震孕育过程伴随物质迁移、能量释放与信息交换。通过遥感手段获取地表、大气及电离层变化信息,进行地震异常分析与前兆识别,已成为遥感与地震科学交叉研究热点。本文收集整理了2008年汶川大地震以来,国内外发表的该地震潜在遥感异常研究论文;回顾了盖层、大气层、电离层的20个遥感参量异常显现的个体特征,分析了其时空关联性,揭示了总体时空特征。研究表明:(1)汶川地震遥感异常显现是逐渐增多、增强和聚拢的,地震短临前兆突出;(2)震前3个月开始,短—临遥感异常由盖层、大气层往电离层渐次显现,与岩石圈—盖层—大气层—电离层(LCAI)耦合范式吻合;(3)短—临遥感异常显现位置与发震断层相关性较强,主要集中于龙门山断裂带(LMSFs)及其周边区域;(4)多种短—临遥感异常区覆盖震中,且多个条带状异常区与LMSFs走向一致,体现了孕震后期LCAI耦合的局地效应。本研究有益于内陆大地震孕育后期的遥感监测分析,也可为地震预测研究提供参考。

Remote sensing anomalies of multiple geospheres before the Wenchuan earthquake and its spatiotemporal correlations

The preparation for the occurrence of an earthquake is a complicated process.This process is usually accompanied with material migration,energy release,and information exchange,which can disturb the radiation balance in the seismogenic zone.Obtaining the changing information of the coversphere,atmosphere,and ionosphere through satellite remote sensing;analyzing seismic anomalies;and identifying earthquake precursors,have become the interactive hotspots of the remote sensing and seismology fields.As a typical case where numerous anomalies precede the main shock,this study investigated the Ms 8.0 Wenchuan earthquake and its physical mechanism of the relevant seismic anomalies.On the basis of published research results,this study systematically collected and filtered the possible remote sensing anomalies of the Wenchuan earthquake under certain criteria and summarized the abnormal features of 20 remote sensing parameters related to the coversphere(five parameters),atmosphere(eight parameters),and ionosphere(seven parameters).By mapping the anomalies in a unified framework,the spatiotemporal correlations among the anomaly manifestations were analyzed,and the overall spatiotemporal characteristics of the short-term manifestations of multiple anomalies were revealed.The results of this study can be summarized as follows.(1)The manifestations of remote sensing anomalies gradually increased,enhanced,and congested before the Wenchuan earthquake,and prominent impending earthquake precursors were observed.(2)Remote sensing anomalies developed in a bottom–up manner from the coversphere and atmosphere to the ionosphere three months before the shock,which is in accordance with the Lithosphere–Coversphere–Atmosphere–Ionosphere(LCAI)coupling paradigm.(3)Strong spatial correlations were present among the seismic faults and manifestation positions of short-term-to-impending remote sensing anomalies,which congested along the Longmenshan faults and its nearby region.(4)Multiple short-term-to-impending remote sensing and strip-shaped anomalies covered the epicenter of the main shock and developed along the Longmenshan faults,respectively,thereby reflecting the local effect of the LCAI coupling in the late stage of the seismogenous process.The clustering multi-parameter remote sensing anomalies before May 12 can be regarded as Wenchuan earthquake anomalies with precursory significance.At the macroscopic scale,the seismic response driven by the deep part of the Earth can be explained using the knowledge on the multiple geosphere coupling of the entire planet system.The in-depth analysis of the individual characteristics,spatiotemporal correlations,and overall laws of the Wenchuan earthquake remote sensing anomalies during the earthquake preparation process is critical to the investigation of the physical mechanism of seismic anomalies.This retrospective research provides heuristic clues about the energy exchange process of the Wenchuan earthquake and confirms the great potential of multi-parameter earthquake precursor research.Furthermore,this study benefits the satellite monitoring and synergic analysis of strong inland earthquakes during the late stage of earthquake preparation and provides reference for earthquake prediction studies.