Calculation and Spectra Analysis of Horizontal Acceleration Correction （HACC） for Airborne Gravimetry     

SHIPan SUNZhongmiao XIAOYun 《地球空间信息科学学报》2004,7(3):204-209

On the basis of a sinusoidal model of the disturbed horizontal acceleration, the spectrum characteristics of misaligned angle and horizontal acceleration correction are analyzed. In an airborne gravimetry test,the misaligned angle of platform and horizontal acceleration correction are calculated. They are 5‘ and 3 mGal,respectively, when the flight is stable.  相似文献   

Burris重力仪性能测试     

张锐  何志堂  郭树松  李辉  郝兴华 《大地测量与地球动力学》2011,31(6):155-158

在武汉重力基准点和庐山短基线场对5台Burris重力仪进行了静、动态测试,数据处理结果表明,Burris重力仪的动态观测精度优于15.0×10 ^-8 ms ^-2,静、动态零漂率很小且均呈线性,重复性标准差优于5.0×10 ^-8 ms ^-2。  相似文献   

宽带地震仪资料证实汶川大地震“震前重力扰动”   总被引：16，自引：6，他引：10       下载免费PDF全文

郝晓光  胡小刚 《地球物理学进展》2008,23(4):1332-1335

在武汉大地测量国家野外科学观测站LacosteET重力仪资料中发现汶川大地震"震前扰动"现象之后,又在全国数十个台站宽带地震仪资料中发现了汶川大地震的"震前扰动".和LacosteET重力仪观测到的"震前扰动"一样,宽带地震仪资料的"震前扰动"也是在震前两天开始并逐渐增大,一直持续到汶川大地震发生,信号周期也是4～8 s.  相似文献   

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张为民  王晓兵  叶文蔚  申建华  郝晓光  钟敏 《大地测量与地球动力学》2012,32(1):149-151

????????????A032??ET??????С???????????????У?????FG5??112?е??????????????SR620??????????????????????????????????????????????????????洢????????????????????????  相似文献   

绝对重力仪测量有效高度确定     

杨萌  钟敏  张为民 《大地测量与地球动力学》2015,35(4):715-717

在重力梯度已知的情况下,认为按照四阶模型得到的重力值为起始高度z=0处的重力值。在被测点重力梯度未知的情况下,推导了一组简单公式用于计算绝对重力仪测量有效高度,该公式适用于初始位置以及初始速度均不为0的情况。用该方法得到的有效高度将计算的100个重力值归算到起始点,精度在1 μGal以内。  相似文献   

Constraining the focal mechanism of the Lushan earthquake with observations of the Earth’s free oscillations   总被引：1，自引：0，他引：1  

Ying Jiang  XiaoGang Hu  ChengLi Liu  HePing Sun 《中国科学:地球科学(英文版)》2014,57(9):2064-2070

The amplitudes of the Earth's free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a superconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3–5 mHz frequency band. The scalar seismic moment M0 has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have minor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inversion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data.  相似文献   

CONSTRAINING THE FOCAL MECHANISM OF THE 2015 NEPAL EARTHQUAKE WITH OBSERVATIONS OF THE CONTINUOUS GRAVITY STATIONS          下载免费PDF全文

JIANG ying  LIU Zi-wei  LI Hui  ZHANG Xiao-tong  WEI-Jin  SHEN Chong-yang 《地震地质》2016,38(3):660-669

On 25 April 2015, a magnitude M_S8.1 interplate thrust earthquake ruptured a densely instrumented region of Nepal. After earthquake, the focal mechanism solutions of Nepal earthquake were provided by well-respected international earthquake research institutions based on different data and methods, which were different. We compared free oscillations observed by 18 spring gravimeters of continuous gravity stations with synthetic normal modes corresponding to 3 different focal mechanisms for the Nepal earthquake, and the focal mechanisms solutions of Nepal earthquake were analyzed and constrained by spherical normal modes in a 2 to 5mHz frequency band. Based on the optimal focal mechanism, the accurate magnitude was searched. The results show that the focal mechanism of Nepal earthquake can be estimated by spherical modes in the 2 to 5mHz frequency band. The synthetic modes corresponding to the focal mechanism determined by the GCMT Moment Tensor Solution showed agreement to the observed modes, the average of misfit factors F was 0.03, and the average of scaling factors was 1.04, which was closest to 1, suggesting that earthquake magnitudes predicted in this way can reflect the total energy released by the earthquake. Based on the focal mechanism solutions provided by GCMT, keeping the strike, dip, slip, depth constant, adjusting the scalar moment, the real scalar moment was searched. When the average of scaling factors was 1, the average of misfit factors F was only 0.03. After calculation, the scalar moment of Nepal earthquake was 8.09×10²⁰ Nm, and the corresponding magnitude was M_W7.91.  相似文献   

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刘冬至  邢乐林  徐如刚  申重阳  李辉 《大地测量与地球动力学》2007,27(2):114-118

??????????????FG5/232????????????????????????????????????????????FG5/232???????????????????????С???2??10 ^-8 ms ^-2????????????????????????????????????????о??????????????????????????13??15???????????????????????????????100??????  相似文献   

L＆R航空重力仪的水平加速度改正     

孙中苗  夏哲仁  李迎春  王兴涛 《测绘科学技术学报》2007,24(4):259-262,266

L&R(LaCoste&Romberg)航空重力仪是我国首套航空重力测量系统的核心,主要由高精度的垂直加速度计和稳定平台组成.前者用于测量总加速度,后者使加速度计保持精确的垂直指向.飞行测量时,由于水平加速度的存在,稳定平台难以精确维持水平从而使加速度计偏离正确指向,由此产生了水平加速度改正.介绍了水平加速度计算的两种基本方法,即两步法与一步法,从理论上导出了其在平台倾角较小情况下的等价性.为有效地减弱因水平加速度改正不完善产生的系统性误差,提出了水平加速度改正的预滤波方法.通过平台倾角的谱分析,确定了预滤波尺度,即采用与平台稳定周期相当的低通滤波器进行预滤波.最后利用实测数据对此进行了验证和分析.结果表明, 利用预滤波尺度, 航空重力测量值与地面向上延拓参考值的系统差由5×10-5 m·s-2减小至0.5×10-5 m·s-2.  相似文献   

Is the instrumental drift of superconducting gravimeters a linear or exponential function of time?     

Michel Van Camp  Olivier Francis 《Journal of Geodesy》2007,81(5):337-344

The instrumental drift of the superconducting gravimeter in Membach, Belgium, is estimated using 9 years of co-located and episodic absolute gravity measurements. We show that the best model of the long-term drift of the SG-C021 is an exponential. The thermal levelers used to compensate tilts are unlikely to induce the observed drift. Rather, the capacitance bridge, magnetic variations, gas adsorption on the levitating sphere, or helium gas pressure variations around it are most likely the possible combined causes of the observed instrumental drift. In practice, either linear or exponential drift models are equivalent as long as the record duration does not exceed 10 years. For longer records, this study demonstrates that an exponential models the drift better than a simple linear trend.  相似文献