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通过对Pion Flat观测点的Gladwin钻孔张量应变仪(BTSM)进行固体潮标定得到的应变数据,我们对地应变进行了估算并分析。小尺度地质上的不均匀性是通过远场面应变/剪应变的交互耦合方法考察面应变/剪应变时所要考虑的因素之一。一种将交互耦合引入应变仪标定的方法由此而生。以同一位置激光应变仪(LSM)观测的固体潮应变为参考,我们发现用交互耦合方法对BTSM标定消除了钻孔固体潮观测值应变中近30%的系统误差。这种标定将钻孔应变和激光应变的测量精度(大约1km)准确地联系在一起了。这种标定技术为短基线应变测量中面临的主要问题(构造应变不能表征小尺度的非均匀性)提供了解决方法。这种方法在断层滑移的残余应变测量中可能减少50%甚至更高的误差,并允许增加滑移机制的约束条件。我们发现就目前仪器而得出的固体潮应变的理论估计值来进行交互耦合标定还不够精确。将理论固体潮与激光应变仪(LSM)观测的固体潮进行比照发现,至少有一半的误差产生于对海洋负荷潮的估计。
We measured and analyzed the geostationary strain by strain data obtained from the calibration of the solid tide at the Gladwin Drill Tensile Strain Gauge (BTSM) at the Pion Flat observation site. Small-scale geologic heterogeneity is one of the factors to be considered in the case of surface strain / shear strain through the cross-coupling method of far-field strain / shear strain. A method of introducing cross-coupling into strain gauge calibration was born. Using the solid tide strain observed by the LSM at the same location as a reference, we found that cross-coupling the BTSM calibration eliminates nearly 30% of the system error in borehole solids tide observed strain. This calibration accurately correlates borehole strain and laser strain measurement accuracy (about 1km). This calibration technique provides a solution to the major problems encountered in short baseline strain measurements (tectonic strain can not characterize small-scale inhomogeneities). This method may reduce the error of 50% or more in residual strain measurement of fault slip and allow to increase the constraint of slip mechanism. We found that the theoretical coupling of the theoretical estimates of solid tide strain derived from current instruments for cross-coupling calibration is not accurate enough. Comparing the theoretical solid tide with the solid tide observed with the LSM, it is found that at least half of the error is due to the estimation of ocean load tide.