Stress Estimation to Mid-Crustal Depth in the KTB Drillhole and In Situ Stress and Heat Flow Measurements in Eastern Europe

地壳应力大小的知识是岩石圈力学广泛问题的基础。这是一个与卡尔斯鲁厄大学合作，在KTB科学钻孔中进行约10公里深度地应力测量的项目。以前从来没有可能在接近地壳中部的深度测量地应力。如果这种测量成功，它将提供机会来检验诸如脆性地壳中的应力水平与摩擦强度平衡的假设等基本概念，该假设由简单的断层理论和实验室确定的摩擦系数值来定义。在与卡尔斯鲁厄大学(以及德国波茨坦的Geoforschung Zentum(GFZ)和美国地质调查局)的相关合作下，首席调查员将在东欧实施一项新的研究计划，以测量东欧和前苏联钻孔中的地应力方向和热流(以及其他地球物理测量)。这项研究的基本思想是利用GFZ获得的几乎新的(和几乎全装备的)地球物理测井系统用于现有的井眼。地应力方向将通过对钻孔电视测量的详细分析确定。随着时间的推移，这些测量将有助于填补关于应力方向和相对大小的知识的极大空白。美国地质调查局将配合这项工作，来自洞穴所在国家的调查人员也将合作。

Knowledge of the magnitudes of stresses in the earth's crust is fundamental to a broad range of problems of lithospheric mechanics. This is a project to make in situ stress measurements to ~10 km depth in the KTB scientific drillhole in cooperation with the University of Karlsruhe. It has never before been possible to measure in situ stress at nearly mid-crustal depth. If such measurements are successful, it will provide the opportunity to test such fundamental concepts as the hypothesis that stress levels in the brittle crust are in equilibrium with frictional strength as defined by simple faulting theory and laboratory-determined values of the coefficient of friction. In a related collaboration with the University of Karlsruhe (and Geoforschung Zentrum (GFZ), in Potsdam, Germany and the U.S. Geological Survey), the Principal Investigator will implement a new research program in eastern Europe to measure in situ stress orientation and heat flow (as well as other geophysical measurements) in boreholes in eastern Europe and the former Soviet Union. The basic idea of this research is to utilize a nearly- new (and nearly fully-outfitted) geophysical logging system acquired by GFZ for use in existing boreholes. In situ stress orientation will be determined from detailed analysis of borehole televiewer measurements. Over time, these measurements will help fill an extremely large gap in knowledge of stress orientations and relative magnitudes. The U.S. Geological Survey will collaborate in this effort as will investigators from the countries in which the holes are located.