基于时序SAR数据的长白山天池火山活动研究  

Analysis on the volcanic activity of Changbaishan Tianchi volcano with time series SAR data

作　　者：魏恋欢 张嘉祺 孙颖 刘国明[2] 敖萌 刘善军[1] WEI LianHuan;ZHANG JiaQi;SUN Ying;LIU GuoMing;AO Meng;LIU ShanJun(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China;National Observation and Research Station of Changbaishan Volcano,Jilin Earthquake Agency,Changchun 130022,China)

机构地区：[1]东北大学资源与土木工程学院,沈阳110819 [2]吉林长白山火山国家野外科学观测研究站,吉林省地震局,长春130022

出　　处：《地球物理学报》2023年第10期4057-4073,共17页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42071453);中央高校基本科研业务费青年教师创新基金(N2201020);中欧合作龙计划五期项目(58029);中欧合作龙计划四期项目(32365_4)资助。

摘　　要：本文面向长白山天池火山活动分析需求,对现有的时序合成孔径雷达干涉测量(Interferometry Synthetic Aperture Radar,InSAR)形变监测方法及火山点源模型进行了改进,提出了一套适合长白山的火山监测方案.首先,针对植被覆盖度高、形变监测受植被失相干影响大的问题,提出了基于归一化植被指数(Normalized Difference Vegetation Index,NDVI)约束的时序InSAR形变监测方法,并利用2004—2010年间的33幅Envisat ASAR影像,提取了长白山天池火山口及周边区域的精确地表形变参数.其次,系统分析了火山地表形变场与雷达视线向(Line of Sight,LOS)之间的立体几何关系,建立了具有普适性的由火山水平形变和垂直形变到LOS向的投影转换关系式,基于LOS向形变的点源模型,反演了长白山天池火山扰动期结束前后的各时段的岩浆房参数.最后,基于改进后的点源模型反演结果,正演了天池火山地表形变场,并将正演结果与地震监测、流体地球化学监测资料进行对比分析,精确评估了长白山天池火山扰动期结束前后岩浆房的变化情况,探讨了长白山天池火山活动由强转弱的过程.本文的研究结果表明,2004—2010年间天池火山岩浆房先经历了短暂的膨胀,以2004年9月8日的ML3.7地震为转折点,地震后开始进入逐步收缩状态,直至2008年趋于稳定.In order to conduct volcanic activity analysis on the Changbaishan Tianchi volcano,a modified time series Synthetic Aperture Radar(InSAR)approach and volcanic point source model is proposed in this paper,which puts forward a set of volcano monitoring scheme suitable for Changbaishan Tianchi volcano.Firstly,in view of the signigicant volume decorrelation problem induced by dense vegetation coverage in the study area,a time-series InSAR deformation monitoring scheme involving point selection based on Normalized Difference Vegetation Index(NDVI)is adopted.Using 33 Envisat ASAR images acquired from 2004 to 2010,the accurate surface deformation parameters of Changbaishan Tianchi volcano are extracted.Secondly,three-dimensional geometric relationship between the volcanic surface deformation field and the radar Line of Sight(LOS)is analyzed,and the original Mogi point source model based on horizontal and vertical deformation is modified to a model based on LOS deformation.Based on the modified point source model,the depths and volume changes of the magma chamber are inverted.Finally,based on the inversion results,surface deformation field of Tianchi volcano is forward modeled and compared with seismic records and fluid geochemical monitoring data,for the purpose of accurately evaluating the volcanic activities of Changbaishan Tianchi volcano.The results of this paper show that from 2004 to 2010,the magma chamber of Changbaishan Tianchi volcano first experienced a short period of expansion,with the ML3.7 earthquake on September 8,2004 as a turning point.After the earthquake,a gradually shrinking state lasted for about four years,and stabilized in 2008.

关 键 词：天池火山 小基线子集干涉测量 形变监测 Mogi模型 岩浆房 

分 类 号：P228[天文地球—大地测量学与测量工程]