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1.
A Review of the Calculation Formula for the Four-component Borehole Strainmeter and Application to Earthquake Cases 总被引：1，自引：0，他引：1
Based on the principle formula for the four-component strainmeters, we can directly obtain the specific plane strain, shear strain and azimuthal angle of the principal strain, and the maximum and minimum principal strains calculated afterwards are the indirect result. The problems of practicality of the sensitivity coefficients A and B of plane strain and shear strain are then discussed. Based on this idea, we analyzed the observation data of several four-component borehole strainmeters near the epicenter of the Yiliang MS5.7 earthquake in 2012 and the Ludian MS6.5 earthquake in 2014 in the Zhaotong area, Yunnan Province. The results show that the analysis based on the perspective of plane strain and shear strain has an obviously better effect than that based on the component readings, and can directly peel off the respective abnormality of the plane strain and shear strain. In addition, the correlation coefficient curves between measured data of two plane strains show significant anomalies which often occur several days before and during the earthquake. 相似文献
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利用湟源台四分量钻孔应变观测的分钟值、1 sps、10 sps和100 sps四种不同采样率的观测数据,通过自检分析、同震应变阶分析和频谱分析等方法研究青海玛多M7.4地震同震变化特征。研究结果表明,分钟采样记录的地震波信息缺失严重,用分钟采样数据进行地震波初动、同震变化幅度等研究将会得到信度较低的结论;采样率越高,记录应变地震波信息的能力越强,但100 sps采样和10 sps采样结果相差不大,10 sps采样已能记录到比较全面的应变地震波信息;同震应变阶的变化性质和变化幅度与采样率无关;未来布设四分量钻孔应变仪时,建议应将采样率至少提高至1 sps。 相似文献
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选取乾陵地震台2018—2020年钻孔体应变观测资料,进行完整性、年零漂和观测资料精度分析,通过采样调和分析,评价观测数据质量,并对自然环境变化、仪器系统故障和人为干扰对观测数据的影响进行分析,探讨该台钻孔体应变观测映震能力,认为： ①乾陵地震台体应变测项运行良好,观测数据质量较高; ②降雨、气压是影响体应变观测数据的主要干扰因素; ③体应变对全球7级以上、中国6级以上地震同震响应较明显,震级越大,同震响应持续时间越长。 相似文献
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Introduction The Earth′s crust deforms in the regional tectonic stress field. Borehole strain observation isone important means for studies on the crustal deformation and the stress field. QIU and ZHANG(2002) have introduced the current situation of borehole strain observation in China. OutsideChina, early in September of 1968, Sacks of Carnegie Institution of Washington and Evertson ofUniversity of Texas firstly invented a borehole dilatometer in the world (Sacks, Evertson, 197… 相似文献
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依据台站两年来实测的地震震级和江苏省区域测震台网定的震级进行比较,计算出各个地震的偏差值和台站的震级校正值,并获得相应的标准误差,最后对影响震级差值因素进行了探讨。 相似文献
6.
正光纤应变仪是利用特种光纤光栅器件或者光纤干涉技术进行高精度应变传感的仪器。常见特种光纤光栅有相移光栅和光纤光栅谐振腔,线宽均较窄,可达到0.01 pm量级甚至更窄,结合高精度解调方法,可显著提高系统的应变测量精度。传统的光纤光栅准静态解调,主要技术方案有光谱分析法、窄带滤波器法、匹配光栅法等,可满足大多数工程应用需求。但高精度地应变传感需求更高, 相似文献
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By using the digital observations of the pendulum tiltmeter, water tube tiltmeter,extensometer and volumetric strainmeter at Huzhou station and with the power spectrum density estimation method,we acquired the_0S_5-_0S_50 fundamental sphere free oscillations caused by the Japan earthquake on March 11,2011,then compared it with the PREM model. The relative errors are mostly bigger than 1.2‰. The extensometer and volume strainmeter can clearly detect _0S_2,_0S_3and_0S_4,which are closely related to the deep structure and earth's interior. 相似文献
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刘序俨 《大地测量与地球动力学》2013,33(4):151-154
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10.
In 2004,China’s digital seismic observation network project began to deploy 40 sets YRY-4 four-component borehole strainmeters in order to monitor earthquake preparation process.The paper describes observed solid tidal strain discreteness and tidal factor anisotropy,analyzes the reliability of observational data and discusses the cause for this phenomenon.After getting rid of interferences,the network,in two years practice,has observed several pre-seismic strain anomalies at stations close to epicenters esp... 相似文献