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   

惯性技术视角下动态重力测量技术评述(二):不同的惯性平台          下载免费PDF全文

常国宾  李胜全 《海洋测绘》2014,(4):73-78

动态重力测量技术是惯性技术的一种典型应用。作为动态重力测量系统不可或缺的一部分,稳定平台的功能是提供一种能够隔离载体动态、实时跟踪参考系的物理装置,或提供载体相对于参考系姿态信息的软件算法。当前大多数的稳定平台,都是基于惯性元件构建的,可称之为惯性平台。从稳定平台的角度对几种常见重力仪进行分类,对采用四种类型惯性平台的重力仪进行较详细的分析和评述,即双轴阻尼陀螺稳定平台、捷联方位双轴惯导平台、三轴惯导平台和捷联惯导平台。  相似文献   

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李哲  胡华  伍康  李刚  王力军 《大地测量与地球动力学》2014,34(1):177-179

2011??3??11?????Ms9.0?????T-1???????????????????????????????????9.0????????????????????????????????????656×10^-8 ms^-2???????????????????á??????????????????????????????????????????????????????????  相似文献   

国产零长弹簧原理动态重力仪首次飞行试验及精度评估     

翟振和  范昊鹏  管斌  马健  段渭超 《测绘通报》2021,(2):68-71

CHZ-Ⅱ重力仪是首套完全国产零长弹簧原理航空重力仪,2018年4月在陕西渭南地区进行了首次飞行试验,共完成4个架次24条测线的有效飞行,标志着我国航空重力仪在自主研发的道路上又取得了长足的进步。利用飞行地区地面重力数据对CHZ-Ⅱ重力仪的测线扰动重力和格网扰动重力数据进行精度评估,其中空中测线在10 km分辨率条件下,精度达到1 mGal。采用地形辅助法对测量形成的5'测格网重力数据进行向下延拓,经延拓至地面后精度优于5 mGal,基本满足平原地区的测量需求。  相似文献   

KSS32-M型海洋重力仪动态性能分析     

李秀敏  付永涛  周章国 《海洋科学》2017,41(8):64-69

采用测网交点差、重复测线和与KSS31-M型海洋重力仪重合测线对比的方法,利用近年来KSS32-M海洋重力仪的实测数据对KSS32-M海洋重力仪测量稳定性和数据可靠性进行分析。利用机动转向法验证重力仪阻尼延迟时间为70 s,基于70 s阻尼延迟时间计算的重力测网的测量准确度为0.65 m Gal,与KSS31-M型海洋重力仪采集的重力剖面对比结果看,重合测线相关性为高度相关,4条重合测线网的交点差绝对值最大为1.66 m Gal,准确度为0.59 m Gal,均达到国家标准要求的近海重力测网交点差均方根小于2 m Gal的技术指标。重复测线的幅值接近,相位吻合,匹配测点异常差的平均值小于0.9,均方根均小于0.8,相关性均在0.98以上。本研究表明KSS32-M型海洋重力仪动态测量性能稳定、测量数据可靠。  相似文献   

国家现代测绘基准体系基础设施建设一期工程绝对重力观测     

何志堂  康胜军  贺小明  赵丕  任敏拴 《大地测量与地球动力学》2017,37(7):747-751

介绍了2013~2014年使用A10/028和FG5/214两台绝对重力仪在国家现代测绘基准体系基础设施建设一期工程中绝对重力观测的情况,并对观测结果进行分析。结果显示,两台绝对重力仪观测结果精度及较差都在5 μGal以内,满足高精度重力基准建设的技术要求;A10/028具有一定的野外观测适应性,FG5/214对重力细微变化信号的捕获具有优势,两台绝对重力仪同期观测对于提高观测结果的可靠性和准确度具有积极的作用。  相似文献   

总结大测程重力仪的分段格值整理重力资料的几种情况   总被引：1，自引：0，他引：1  

范祥发  王亮  朱大友 《物探与化探》1999,23(4):301-304

对于大测程重力仪,当分段标定的格值相对变化大于1/1400时,应使用分段格值对重力资料进行整理.文中总结了如何使用重力仪的分段格值计算在不同测程段上观测点重力值可能出现的几种情况.  相似文献