【摘要】 根据四分量钻孔应变观测的弹性理论模型,四个分量的观测值S1、S2、S3、S4之间存在"自洽方程":S1+S3=S2+S4。"十五"期间新建的"数字地震观测网络工程"四分量钻孔应变观测系统中已有一批台站,无论是几天的短期数据,还是6年以上的长期数据,两组面应变相关系数k值都超过了0.99。k值不受降雨、河湖水位、机井抽水等外界干扰影响,具有稳定性。但姑咱台和昭通台,分别在汶川8.0级、鲁甸6.5级和康定6.3级地震前,观测到了k值发生明显变化即数据自洽性遭到破坏的现象。导出自洽方程的条件是安装应变仪钻孔附近岩石完整及应力源与观测点间介质的连续性要求,由此,作者认为,姑咱台和昭通台面应变相关系数发生变化可能由于台站附近发生的大地震的地震成核过程中震源区地层介质连续性逐渐受到破坏所致。更多还原

【Abstract】 According to the elastic theory of four component borehole strain observation,there exists a"self-consistent equation":S1+S3=S2+S4for S1,S3,S2,S4.Many four component borehole strain observation stations have correlation coefficient k of two groups of plain strain values more than 0.99 whether it is for short term of several days or for long-term of more than 6years.Coefficient kis not affected by external interference.But at Guzan station and Zhaotong station,before the Wenchuan M8.0,Ludian M6.5and Kangding M6.3earthquakes,we have observed the plain strain correlation coefficient kvaried obviously.The self-consistent equation rely on the medium continuity between strain source and the observation point,therefore,the authors think,this significant strain correlation coefficient changes was due to gradual damage of earthquake source region stratum for the earthquake nucleation process.更多还原