中国大陆重力潮汐参数及其特征研究

给出了我国某些台站１９８９－１９９３年重力固体潮的观测结果,叙述了进行有关的改正的原理、方法、并给出经过改正后的潮汐参数。     

兰州地区(1959-1989)重力潮汐参数的测量与结果

本文介绍了兰州地区历次重力固体潮测量的概况,给出了不同仪器历次测量所得的重力潮汐参数。对比分析了Geo—765重力仪和改型后的GS11—150重力仪观测资料月调和分析主波潮汐因子的重复精度,评价了改型后的GS11—150重力仪今后对兰州地区地震的监测能力。文中还给出了该仪器改型前在天水观测的部分结果。     

武汉台重力潮汐长期观测结果

采用武汉台超导重力仪(SG C032)14年多的长期连续观测资料,研究了固体地球对二阶和三阶引潮力的响应特征,精密测定了重力潮汐参数,系统研究了最新的固体潮模型和海潮模型在中国大陆的有效性.采用最新的8个全球海潮模型计算了海潮负荷效应,从武汉台SG C032的观测中成功分离出63个2阶潮汐波群和15个3阶潮汐波群信号,3阶潮波涵盖了周日、半日和1/3日三个频段.重力潮汐观测的精度非常高,标准偏差达到1.116 nm·s-2,系统反映了非流体静力平衡、非弹性地球对2阶和3阶引潮力的响应特征.结果表明,现有的武汉国际重力潮汐基准在半日频段非常精确,但在周日频段存在比较明显的偏差,需要进一步精化.对于中国大陆的大地测量观测,固体潮可以采用Dehant等考虑地球内部介质非弹性和非流体静力平衡建立的固体潮理论模型或Xu 等基于全球SG观测建立的重力潮汐全球实验模型作为参考和改正模型,海潮负荷效应应该采用Nao99作为改正模型.     

用重力勘探直接寻找油气藏的可能性

石油工业的迅速发展,要求石油勘探者多快好省地发現和开发祖国的地下油气藏.各种地球物理勘探方法直接寻找油气藏的可能性已引起大家的注意.作者根据有限的苏联文献和国內資料,就重力勘探直接寻找油气藏的可能性提出初步看法,以供探討. 苏联某些地区在短軸背斜构造的頂部往往发現有面积和,隕度不大的重力負异常.引起这些負异常的地貭因素以往大多数人认为是由于比直接复盖在上面密度較小的沉积岩隆起,或是褶皺頂部岩石比較疏松等原因所引起的.經过对岩石密度資料的研究証明以上的因素并不存在.     

用重力勘探直接寻找油气藏的可能性

石油工业的迅速发展,要求石油勘探者多快好省地发現和开发祖国的地下油气藏.各种地球物理勘探方法直接寻找油气藏的可能性已引起大家的注意.作者根据有限的苏联文献和国內資料,就重力勘探直接寻找油气藏的可能性提出初步看法,以供探討. 苏联某些地区在短軸背斜构造的頂部往往发現有面积和,隕度不大的重力負异常.引起这些負异常的地貭因素以往大多数人认为是由于比直接复盖在上面密度較小的沉积岩隆起,或是褶皺頂部岩石比較疏松等原因所引起的.經过对岩石密度資料的研究証明以上的因素并不存在.     

中国大陆精密重力潮汐改正模型

利用理论和实验重力固体潮模型,充分考虑全球海潮和中国近海潮汐的负荷效应,建立了中国大陆的精密重力潮汐改正模型.结果表明,采用不同的固体潮模型会对重力潮汐结果产生相对变化幅度小于0.06％的差异;在沿海地区海潮负荷的影响约为整个潮汐的4％,而中部地区约为1％,其中中国近海潮汐模型的影响约占整个海潮负荷的10%,内插或外推潮波的负荷约占海潮负荷的3％.通过比较实测的重力数据表明,本文给出的重力潮汐改正模型的精度远远优于0.5×10-8 m·s-2,说明了本文构建的模型的实用性,可为中国大陆高精度重力测量提供有效参考和精密的改正模型.     

中国东西重力潮汐剖面

为了检验体潮与海潮的理论模型,分析了中国东西重力潮汐剖面（1981年9月—1985年1月）。同时,为研究LaCoste ET-20和ET-21重力仪的格值系统,建立了一条由17台LaCoste G型和2台LaCoste D型重力仪观测的重力垂直基线。在基线上标定的结果表明,ET-21重力仪的格值大了1％。由标定得到的格值计算剖面上各测站的潮汐因子,经海潮改正后,接近Wahr模型值,振幅因子的残差:O1波小于0.3μGal,M2波小于0.4μGal。但是上海和拉萨的观测经海潮改正后,相位迟后有很大的改善,振幅因子却更偏离于模型值,其潮汐异常主要是近海的海潮模型不完善,以及在海潮计算中,所采用的地球模型未考虑地壳与上地幔的横向不均匀性所引起。     

中国东西重力潮汐剖面

为了检验体潮与海潮的理论模型,分析了中国东西重力潮汐剖面（1981年9月-1985年1月）。同时,为研究LaCoste ET-20和ET-21重力仪的格值系统,建立了一条由17台LaCoste G型和2台LaCoste D型重力仪观测的重力垂直基线。在基线上标定的结果表明,ET-21重力仪的格值大了1％。由标定得到的格值计算剖面上各测站的潮汐因子,经海潮改正后,接近Wahr模型值,振幅因子的残差:O₁波小于0.3μGal,M₂波小于0.4μGal。但是上海和拉萨的观测经海潮改正后,相位迟后有很大的改善,振幅因子却更偏离于模型值,其潮汐异常主要是近海的海潮模型不完善,以及在海潮计算中,所采用的地球模型未考虑地壳与上地幔的横向不均匀性所引起。     

连续重力观测潮汐与非潮汐信号提取与处理平台设计与实现

介绍了连续重力观测潮汐与非潮汐信号提取与处理平台的平台架构、数据库、主要功能模块、技术特点与功能特性等。该平台面向中国地震重力站网的大网运维业务需求和海量数据处理需求,以连续重力数据处理中的潮汐信号处理、非潮汐信号处理、时频变换等科学计算为核心,基于大数据技术实现了中国地震重力站网海量数据的自动清理、数据质量自动评估、数据产品自动产出,产出重力潮汐因子、时频图等24种数据产品,提升了连续重力观测数据的应用效能和地震重力站网的运行、管理和服务水平。     

武昌重力潮汐基准研究

为了检验和完善理论地球模型和海潮模型,必须提高重力潮汐观测的精度。这除了提高仪器的精度以外,关键问题在于仪器的格值的准确性,因为它是衡量潮汐参数的尺度。但是,各种类型重力仪的出厂格值存在着误差,且各成系统,其系统偏差可达1％-2％。需要高精度的潮汐基准与之比较,统一和确定重力仪的格值。根据国际地潮中心的观测结果分析,布鲁塞尔潮汐基准系统可能偏大。因此,建立我国重力潮汐基准,对固体潮观测与研究具有重要意义。     

Analysis of the tidal gravity observations in Three Gorges reservoir area

The comparative observations of the tidal gravity in Three Gorges reservoir area, recorded with the LCR-ET20 gravimeter from Institute of Geodesy and Geophysics, Chinese Academy of Sciences and the DZW-9 gravimeter from Institute of Seismology, China Earthquake Administration, are introduced. High-accuracy tidal gravity pa-rameters in this area are obtained, and the scale factor of the DZW-9 gravimeter is also estimated at a value of ?(756.06±0.05)×10?8 m?s?2V?1. The observed residuals of the corresponding instruments are investigated. Nu-merical results indicate that the long-term drift of the DZW-9 gravimeter appears a linear characteristic, and the observed accuracy is of the same order comparing with that of the LCR-ET20 gravimeter. The results given in the paper can provide with an effective reference model of the tidal gravity correction to the ground based and space geodesy.     

Study on tidal gravity observations obtained at stations Zhongshan and Changcheng, Antarctic

IntroductionThe purpose of the studies on the tidal gravity observations on the Earth(s surface is to investigate the properties of the deformation and the tidal gravity variations of the Earth under the action of the luni-solar tidal force. These variations relate to the internal structure, shape and the medium(s rheology properties of the Earth (Wahr, 1981; Dehant, 1987). The theoretical studies and observations indicated that the amplitudes and the tidal parameters, including the amplitud…     

基于Matlab GUI的全球重力固体潮可视化实现

阐明重力固体潮理论值计算原理,利用改进的计算新方法编写Matlab计算程序,采用Matlab中的GUI平台,对全球重力固体潮进行可视化实现,直观观察固体潮在地面的时空变化规律。通过输入时间和经纬度,确定采样间隔(秒采样、分钟采样、时采样),实现以下功能:(1)以图像和Excel形式,输出某一地区的重力固体潮理论值;(2)仿真未来24小时全球重力固体潮。     

用小波分析提取重力固体潮

地球固体潮观测对验证各种地球模型、研究地球内部构造具有重要意义,可为地震预报提供重要的参考依据.BBVS-120甚宽带地震计具有较低的自噪声水平,在低频端输出信号的频率很低,涵盖固体潮信息频带范围.本文提出:BBVS-120地震计输出信号中存在周日波、半日波和1/3日波的固体潮信号,利用小波分析,提取垂直分量中的重力固体潮信号,并作调和分析.     

Synthetic tidal parameters for gravity over China and its neighbor area

The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are con- structed with Earth’s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravime- ters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravim- etric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric obser- vations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.     

Research on distinguishing method and mechanism of tidal deformation anomalies before large earthquakes

Introduction There are many researches on modulating and triggering seismic activities by tidal force in China and abroad. Heaton (1975) studied the tidal triggering of seismic activity and discovered that the tidal stress did have an obvious triggering action on the dip-slip or oblique slip great earthquakes. Tidal triggering of earthquakes has been studied for a long time in China, especially in recent years. For example, LI et al (2001) provided the relationship between the solar and luna…     

强震前的重力变化特征

地震前,地壳变形引起地球密度重新分布,从而使地球重力场发生某些特征变化。本文对1990年7月菲律宾8级、台湾6.1级两个强震前后的广州重力资料进行了调和分析及高、低频滤波等处理,并对提取出的重力前兆进行了可信度检验。结果表明强震前广州地区的重力变化具有O_1等主波潮汐因子波形畸变,量值下降至最低值然后在回升阶段发震的前兆异常特征。非潮汐重力变化在临震前3天开始出现明显的高频脉冲式异常信息,作者认为这是一种可信的具有清晰物理意义的地震短临前兆。     

International tidal gravity reference values at Wuhan station

The international tidal gravity reference values at Wuhan station are determined accurately based on the comprehensive analysis of the tidal gravity observations obtained from 8 instruments. By comparing these with those in the tidal models given by Dehant (1997) while considering simultaneously (i) the global satellite altimeters tidal data, and (ii) the Schwiderski global tidal data and the local ones along the coast of China, it is found that the average discrepancy of the amplitude factors and of the phase differences for four main waves are given as 5.2% and 3.6% and as 0.16° and 0.08° respectively. They are improved evidently compared to those determined in early stage, indicating the important procedures in improving the Wuhan international tidal gravity reference values when including the long-series observations obtained with a superconducting gravimeter, and when considering the influence of the ocean loading and of the nearly daily free wobble of the Earth’s core.     

preliminary discussion on horizontal gravity gradient and its application to seismic gravity precursor research

In this paper, according to the synthetic gravity anomaly of a horizontally infinite cylindrical geologic body, gravity gradient in horizontal direction was calculated by potential field discrete cosine transformation in frequency domain. In the calculation, the minimum curvature method was used to extend edge lines. We found that the gravity gradient field from the potential field transformation was dependable by comparison with synthetic gravity gradient, except the data in the edges. Then, the accumulative horizontal gravity gradients before Lushan M_S7.0 earthquake were calculated for the accumulative gravity anomaly from September 2010 to October 2012. In the north-south direction, gravity gradient in Daofu-Kangding-Shimian and Markang-Lixian-Lushan exhibited a positive high value, and the strike of the high value zone was in line with the strike of Xianshuihe Faults and Markang Faults. In the east-west direction, high value zone was not as obvious as that in the north-south direction. Gravity gradients in the direction along and vertical to the strike of Longmenshan Faults were calculated by the definition of directional derivative. In the along-strike direction, high gravity gradient values appeared in Markang-Lixian areas along Markang Faults and Daofu-Kangding-Shimian areas along Xianshuihe Faults, and extremum appeared in Kangding-Shimian and the area nearby Lixian. In the direction vertical to the strike of Longmenshan fault zone, high gravity gradient values appeared in Lixian-Lushan-Kangding-Shimian areas, and the extremum appeared in the area nearby Kangding. The results indicate that gravity gradient in the direction along and vertical to the strike of faults can better show the relative gravity change on the two sides of faults. Lushan M_S7.0 earthquake is located at the transition zone between the two high value zones of gravity gradient. The total horizontal gravity gradient shows that the location and strike of the high value zone are basically consistent with regional faults, and the extremums of total horizontal gravity gradient appeared nearby Lixian, Kangding and Shimian.