Fundamental and Applied Investigations in Rock Physics and Mechanics

实验地球物理小组（EGG）研究控制地球物质物理性质的因素，并将这些知识应用于下一代地球物理观测的解释。调查既在受控的实验室条件下进行，也在现场进行地面和钻孔测量。主要的兴趣集中在测量地球上的应力，包括它们的方向和强度。在EGG工作的学生有机会参加越来越少的实地活动。这一建议寻求支持，使我们能够继续在科学钻探项目中进行合作，并开展新的岩石物理实验室实验。*我们是两个即将到来的科学钻探项目的科学小组的成员。首先，将在新西兰南岛的阿尔卑斯断层上钻一个1.5公里深的钻孔。阿尔卑斯断层连接太平洋和澳大利亚板块，是一个重要的地壳特征，被显著的隆起所容纳，人们担心这个断层会产生毁灭性的大地震。该钻孔预计将于2014年底开始钻探，预计将在约1公里的深度与断层相交。EGG将在测井程序中承担重要责任，该程序将提供沿井眼的基线物理属性数据，整个科学团队将使用这些数据来关联岩心并协助了解原位条件。这项工作将对理解导致大地震的板块边界断层运动产生影响。*我们也是考尔曼高地（Coulman High）钻探的科学团队的一员，这是一个海底区域，在新生代的大部分时间里，这里收集了来自南极洲的沉积物。同样，我们的任务是记录操作，我们希望派遣一名训练有素的博士生来完成这项工作。在这种情况下，测井数据将是确定岩心材料在适当深度的关键。这些日志将寻找从开阔海洋到冰雪覆盖的沉积模式；这些信息揭示了过去气候变化的模式，因为世界这一地区开放海洋的指标强烈表明，当沉积物沉积时，地球各地普遍较暖。然而，我们的主要兴趣将集中在井眼应力状态的确定上。我们的实验室研究将集中在两个主题上。第一种方法检查各向异性层的地震反射。虽然这项工作具有更基本的性质，但对反射如何随入射角和方位角变化有一个很好的理解，对于正确解释工业地震勘探是必要的，因为工业地震勘探试图表明原位压裂的模式。这些知识对于规划低渗透地层的碳氢化合物钻井和长期注入地质隔离的温室气体至关重要。我们将使用一种叫做声波测角仪的专门仪器来测量各向异性材料块反射的超声波脉冲振幅的变化，以模拟现场条件。*最后，我们将继续进行地震频散的实验室研究，即地震波速度和衰减随频率的变化。目的是确定如何调和在1兆赫的非常高频率下进行的实验室测量与在100赫兹频率下获得的现场地震观测。我们目前正在开发新的仪器来直接测量低频下的体积模量。这与其他的测量方法不同，因此新的仪器应该为研究频散提供一个新的工具。

The Experimental Geophysics Group (EGG) investigates the factors that control the physical properties of earth materials and applies this knowledge in next generation interpretation of geophysical observations. Investigations are carried out both in controlled laboratory conditions and in the field with surface and borehole measurements. A major interest focusses on measurement of the stresses in the earth, both their directions and their strength. The students working with EGG have the opportunity to participate in the field activities that are increasingly rare. This proposal seeks support to allow us to continue collaboration in scientific drilling programs and to carry out novel rock physics laboratory experiments. *We are part of the science team for two upcoming scientific drilling programs. In the first, a 1.5 km deep borehole will be drilled through the Alpine Fault on the South Island in New Zealand. The Alpine Fault bounds the Pacific and the Australian plates and is a significant crustal feature accommodated by significant uplift, it is feared that this fault can produce a major earthquake with devastating. The borehole, with drilling expected to begin in late 2014, is slated to intersect the fault at a depth of about 1 km. EGG will take significant responsibilities for the logging program that provides baseline physical property data along the borehole that will be used by the entire science team to correlate core and to assist in understanding in situ conditions. This work will have implications for the understanding of plate boundary fault motions leading to large earthquakes.*We are also in the science team for drilling at Coulman High, a seafloor area that has collected sediments from Antarctica for much of the Cenozoic. Again, we are tasked with logging operations and we expect to send a trained Ph.d. student to carry out this work. In this case, the logging data will be key to locating in proper depth the core materials. The logs will look for patterns in sedimentation that switch from open ocean to ice covered; this information reveals patterns of past climate changes as indicators of open ocean in this part of the world strongly suggest that when the sediment was deposited the planet was generally warmer everywhere. Our primary interest, however, will focus on determination of stress states in the borehole. *Our laboratory studies will concentrate on two topics. The first examines seismic reflections from anisotropic layers. While this work is of a more fundamental nature, having a good understanding of how the reflections change with both angle of incidence and azimuth is necessary for the proper interpretation of industrial seismic surveys that seek to indicate the patterns of in situ fracturing. Such knowledge is key to the planning of drilling for hydrocarbons in low permeability formations and for long term injection of geologically sequestered greenhouse gases. We will use a specialized instrument called an acoustic goniometer to measure the variations in the amplitudes of ultrasonic pulses reflected from anisotropic blocks of materials in order to simulate in situ conditions. *Finally, we will continue laboratory research on seismic dispersion, i.e. the changes in the seismic wave speeds and attenuation with frequency. The purpose is to determine how to reconcile laboratory measurements taken at very high frequencies of 1 MHz with field seismic observations acquired at frequencies of 100 Hz. We are currently developing new instrumentation to measure directly the bulk modulus at low frequencies. This differs from all other measurements in the and as such the new instrumentation should provide a new tool for studying frequency dispersion.