乌鲁木齐及周边地区重力场及视密度变化特征  

STUDY ON THE VARIATION CHARACTERISTICS OF GRAVITY FIELD AND APPARENT DENSITY IN URUMQI AND ITS SURROUNDING AREAS

作　　者：孔祥魁 刘代芹[2,3,4] 艾力夏提·玉山 李杰[2,4] 陈丽 李瑞[2,4] 陈荣柳 KONG Xiang-kui;LIU Dai-qin;AILIXIATI·Yushan;LI Jie;CHEN Li;LI Rui;CHEN Rong-liu(Xinjiang University,Urumqi 830046,China;Earthquake Agency of Xinjiang Uygur Autonomous Region,Urumqi 830011,China;School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;Urumqi Institute of Central Asia Earthquake,CEA,Urumqi 830011,China)

机构地区：[1]新疆大学,乌鲁木齐830046 [2]新疆维吾尔自治区地震局,乌鲁木齐830011 [3]中国科学技术大学,地球和空间科学学院,合肥230026 [4]中国地震局乌鲁木齐中亚地震研究所,乌鲁木齐830011

出　　处：《地震地质》2024年第5期1123-1150,共28页Seismology and Geology

基　　金：新疆维吾尔自治区重点研发专项(2020B03006-2);地震科技星火计划项目(XH22007YA);新疆维吾尔自治区自然科学基金(2022D01A106);新疆维吾尔自治区自然科学基金(2023D01A105);国家自然科学基金(42274014);国家重点研发计划项目(2022YFC3003703);国家外国专家局引智项目(G2022045013L);第3次新疆综合科学考察(2022XJKK1305);新疆地震局科技创新团队计划(XJDZCXTD2020-1)。

摘　　要：文中基于2019年4月—2022年4月乌鲁木齐及周边地区流动重力观测资料,采用绝对重力控制进行经典平差计算,获取研究区重力场时空演化特征图像。针对0.5a尺度和1a尺度重力场变化并结合构造地质部位分析重力剖面变化图像,分析了乌鲁木齐及周边地区的重力场变化特征。此外,文中采用小波多尺度分析方法,对乌鲁木齐及周边地区2019—2020年、2020—2021年和2021—2022年3a的重力场动态变化数据进行处理,分解不同场源异常,并对分离出的异常信息进行解释和分析,以此提升地震前兆重力异常的可信度。结果表明,研究区重力场具有明显的分区特征,整体以负值变化为主,正、负重力变化交替出现;小波重力细节反映异常区域与地质构造吻合,功率谱估算的近似场源深度与crust1.0模型相近;此外,基于流动重力观测资料反演得到研究区地壳内部等效视密度变化特征。文中的研究成果将为研判乌鲁木齐及周边地区未来的重力场变化趋势提供初步依据。Using seasonal gravity observation data from Urumqi and its surrounding areas,collected between April 2019 and April 2022,this paper applies absolute gravity control to perform classical adjustment calculations,identifying the spatial-temporal evolution characteristics of the gravity field in the study area.The relationship between seismic activity and gravity change has long been a topic of interest.The time-varying gravity field is a fundamental physical field that reflects the migration of mass and directly represents the internal tectonic movements of the Earth and surface mass redistribution.The link between earthquakes and gravity changes is primarily related to tectonic movement and variations in mass(density)within the Earth’s interior.By examining gravity field changes at half-year and one-year scales and analyzing gravity profile images in relation to geological structures,this paper explores the characteristics of gravity field variations in Urumqi and its surrounding areas.To effectively separate gravity anomalies at different depth levels,wavelet multi-resolution analysis is employed to decompose the gravity field anomalies,distinguishing regional from local anomalies in the study area.Specifically,the wavelet multi-scale analysis method is applied to process gravity field dynamic data from 2019-2020,2020-2021,and 2021-2022.This method helps isolate and interpret abnormal signals in the gravity field,improving the reliability of earthquake precursor gravity anomalies.The gravity source characteristics provide insight into the physical property changes of the crust.In this study,the“equivalent source”inversion model is used to determine the dynamic characteristics of the crust’s apparent density.The multi-period gravity point values obtained through the adjustment method serve as input data for the equivalent source apparent density change model in the study area.The results indicate that the gravity field in the study area exhibits clear zonation,with predominant negative changes and alternat

关 键 词：重力场变化 小波分解 功率谱 视密度反演 地震 

分 类 号：P315.726[天文地球—地震学]