Study of the Gravity Changes before and after the Jingtai Ms 5.9 Earthquake

By systematically analyzing the data of gravity reiteration in the Hexi region and taking a dynamic viewpoint.we have studied the evolution characters of gravity field during the preparation-occurrence of the Jingtai Ms5.9 earthquake of June 6,2000,The patterns of dynamic change of the gravity field clearly reflected how the gravity field evolved from the quasi-homogeneous state to non-homogeneous state for earthquake preparation and then the earthquake occurred.Besides,we have also studied the relation between the characteristic gravity change and strong earthquake activity.     

The Role of Gravity, Magnetic and Electric Prospecting Techniques in the Geological Survey of the Qiangtang Basin

The Qiangtang basin is one of the large-scale basins in China, which is located in the high-altitude and cold area. In 1994 the preliminary gravity, magnetic and electric prospecting work was undertaken in this area. Over three years the gravity, magnetic and electric reconnaissance work had been completed. The integrated interpretation of complex gravity, magnetic and electric data had identified the boundary of the basin. The relationship between the basin and mountains is a south-north ramp structure. The basin structure consisted of one uplift and two sags, five depressions and two arches. The complex evaluation showed that the regions of Baitanhu and Youyiquan in the Qiangtang basin were considered to be the most perspective ones in sense of oil-gas bearing.     

Geological structure of the yellow sea area from regional gravity and magnetic interpretation

Regional gravity and aeromagnetic data covering the area of 32°- 38° N, 118°-127° E at the scale of 1：1,000,000 are coordinated and integrated in a synthetic study of the South China Yellow Sea and adjacent areas. Depth to magnetic crystalline basement and its structure are determined by magnetic anomaly inversion. Depth to and thickness of the Paleozoic rock are also revealed by gravity anomaly inversion with constrains of the basement and known seismic information from several profiles. Structure units, main faults, basin boundaries, and sub-suppressions are outlined on the basis of gravity data interpretation.     

Gravity change and its mechanism after the first water impoundment in Three Gorges Project

Introduction During and before the construction of the Three Gorges Project, the annual observation was continuously undertaken by the Three Gorges gravity observation network established around the head area of the reservoir (the section between Sandouping and Badong). This network has pro-vided substantial high precise data related to seismic activity. However, the annual gravity survey together monitoring of the existed observation stations can hardly effective monitor some potential sei…     

Modeling the Dynamic Gravity Variations of Northeastern Margin of Qinghai-Xizang （Tibet） Plateau by Using Bicubic Spline Interpolation Function

INTRODUCTIONThe study of earthquakeforecast based on gravity measurement has been carried out for almost30yearsin China,and remarkable progress has been made(Jia Minyu,et al.,2000;Zhu Yiqing,etal.,2001).However,constrained byobservationtechniques and moni…     

Inversion of gravity and topography data for the crust thickness of China and its adjacent region

Introduction Since the middle of the century, gravitational isostasy has been a fundamental hypothesis for inverting the gravity data to find the crust thickness. Geophysicists have done a lot of researches on using gravity data to investigate the depth of Moho discontinuity. Since 1980, the International Lithosphere Program emphasized the importance of investigating the Moho depth variation. Thereafter a lot of results have been published in the world (Braitenberg et al, 2000; Kaban et al,…     

我国绝对重力观测结果和重力测量精度

文内给出全国３６个点绝对重力观测结果。观测结果表明，在国家重力基本网的一些点上，其重力值新测绝对重力值之间存在明显偏差。     

Application of Integrated Geophysical technology and Its Effects in the Qaidam Basin

Experience gained in many years proved that oil explorations were very difficult to complete with seismic methods only in seismic-unfeasible areas. The expected results in these places could only be obtained with the integrated geophysical surveys, the combination of gravity, electric, magnetic,geochemistry and seismic methods. The high-precision gravity,magnetic and electric techniques used in seismic-unfeasible areas in Qaidam Basin had achieved many astonishing results,which demonstrated a feasible way for oil exploration in Qaidam Basin and offered a basis for data interpretation in complex areas where seismic data was not able to acquire.     

广西北流—广东化州5.2级地震前粤桂琼地区重力变化特征

收集了粤桂琼地区4个台站的连续重力观测资料和雷琼地区的流动重力观测资料,研究了广西北流—广东化州5.2级地震前粤桂琼地区重力变化特征。其中连续重力观测资料的分析从重力扰动和重力M2波潮汐因子变化两个方面进行;流动重力观测资料的分析从重力场差分动态和累积动态变化两个方面进行。连续重力观测资料的研究表明震前粤桂琼地区连续重力观测资料无异常现象;雷琼地区流动重力观测资料的研究结果表明,广西北流—广东化州5.2级地震前,震中附近地区存在重力场变化异常,异常持续时间约2年,异常范围约100 km,异常量级约50x10~(-8)m·s~(-2),地震发生于重力场变化的高梯度带上。     

重力测井技术若干进展

重力测井是一种常规的地球物理方法,具有较大探测深度,对以生物礁及溶孔溶洞为储层的密度异常体的探测具有重要的意义。本文论述了重力测井的研究进展,分析了重力测井的基本原理以及面临的问题和急需解决的科学问题,讨论了今后需要研究的方向及基本课题.认为重力测井在解决复杂储层勘探难题和油气藏动态监测方面具有其它常规测井所不具有的优势,重力测井技术在理论和实践两方面都是可行的,具有广阔的发展前景.     

西藏高原地区重力测量与研究

对实测的西藏高原布格重力异常和自由空间异常的分析发现,青藏高原四周为重力异常梯级带、地壳厚度陡变带和一系列深大断裂带,从而推断青藏高原可能为一断块高原;现代欧亚板块和印度板块碰撞挤压带不是雅鲁藏布江断裂带,而是在喜马拉雅山和雅鲁藏布江的中间地带。对重力复测资料分析的结果表明,西藏地区重力场变化之敏感点在雅鲁藏布江与其稍偏南一带以及该区北东向的深大断裂带上。西藏地区的地壳运动尤其是新生代以来的地壳活动也集中表现在深大断裂带及其附近。     

地质矿产部区域重力调查成果与展望

区域重力调查是一项基础地球物理调查工作。它的成果可用于研究地质构造、资源勘探、环境调查，地震灾害、地球形状、地球物理理论等方面。它象征着一个国家科学技术发展水平，特别是地学方面的水平。地矿部研究了国内外重力勘查情况，于１９７８年提出并组织、实施了全国范围的区域重力调查。通过十多年的工作，取得了丰硕成果。本文就地矿部区域重力调查成果与展望，予以论述。     

绝对与相对重力同步比测中的拉科斯特重力仪标定

采用害虫级数和三角多项式模拟ＬＣＲ－Ｇ型重力仪格值函数,利用绝以与相对重力比测数据进行标定。     

离散时变重力数据的可视化、指标量定义与解释

针对流动重力观测获得的数据成果特点,提出一种基于流动重力段差变化的时变重力数据可视化方法,并定义了两个指标量G值和C值,用以评价区域性重力场变化的显著性程度.在此基础上,应用该方法处理和分析了首都圈地区的流动重力数据.结果表明:与传统采用等值线方式来刻画时变重力场特征不同,该方法更能突出发生变化的重力测点位置、测量误差及其变化的显著性程度,可为研究与地震孕育、发生过程有关的重力场变化提供更多的定量依据.      

北京站重力潮汐分析及海潮负荷效应

采用引潮势和海潮潮族作为输入函数,对北京实测的重力潮汐进行了响应分析,将频率相同的引潮力产生的重力天文(引力)潮和海洋潮汐负荷效应产生的重力负荷潮分离开.再对重力天文潮和负荷潮进行调和分析,得到北京重力天文潮和负荷潮的平均变幅分别为121.5和7.5微伽.海洋潮汐的负荷影响为北京重力天文潮的6.2%.     

安庆5.2级地震震前区域重力场动态变化特征

根据安徽省及周边区域地震动态重力监测网2009-2010年期间的3期绝对重力和相对重力观测成果,给出了监测区域重力场动态变化图像,并以此为基础从场变化的角度分析了安庆地震震前区域重力场的动态变化特征.     

陆地高精度重力观测数据的应用研究进展

陆地重力观测相较于航空和卫星重力观测,距离场源更近,观测精度相对较高,其静态异常和时变数据已广泛应用于研究多种地球动力学问题.21世纪以来,绝对重力观测技术发展迅速,陆地观测网络日益完善,高精度陆地重力观测数据产品逐渐丰富,基于这些产品的大地测量和地球物理研究不断取得新进展.本文总结了近十几年来高精度陆地重力观测数据在大地测量和地球物理领域的应用进展情况,包括基于重力异常数据构建重力场和大地水准面模型、建立地壳物性结构模型、反演Moho界面形态和估计岩石圈有效弹性厚度,以及利用时变重力数据构建时变重力场模型、探测微弱动力学信号、估计地壳构造变形速率和分析与火山、地震过程的可能关联,最后探讨分析了陆地重力测量的未来发展趋势,可为中国大陆重力观测系统建设与发展规划提供参考.