基金项目:中国地震局三结合课题(200604)资助.
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宁夏海原台四分量钻孔应变观测的相对标定结果显示,标定后分量1、分量3之和与分量2、分量4之和的资料相关性显著增强,标准差明显减小,更加满足四分量应变仪的校核条件,表明该钻孔应变观测资料是可靠的。将各分量应变资料去趋势,计算出面应变1+3和2+4、差应变1-3和2-4,对面应变、差应变资料和相对标定系数在2008年4月6日固原3.8级、5月12日汶川8.0级、10月3日固原4.0级和11月24日固原3.8级地震前的异常变化进行了分析探讨。结果 显示,钻孔应变观测的相对标定及资料应用有助于地震前兆异常的判定识别。
The relative calibrated result of 4-component borehole strain observation in Haiyuan station indicate the correlation between the sum of the calibrated component 1 and 3 and the one of component 2 and 4 increases significantly with fewer standard error,and it hold goodness of fit with check condition of the 4-component strain meter.The result illustrates the observations data are credible.The strain data are minus trend,and hold the surface strains 1+3 and 2+4 and the differential strains 1-3 and 2-4.The data of the surface strain and differential strain and calibration coefficients display the abnormal changes before the earthquakes,such as MS3.8 in Guyuan June fourth,2008,MS8.0 in Wenchuan May twelveth,2008,MS4.0 in Guyuan Oct.third,2008 and MS3.8 in Guyuan Dec.24th,2008.The result indicates the relative calibration and its application of strain observation will be benefit for distinguishing precursory abnormal before earthquake。