VSP and Seismic Reflection Investigation of Fluid Flow and Structural Evolution at the Oregon Margin Accretionary Prism

收敛边缘吸积棱柱是构造复杂的地质特征。这是一项建议，在俄勒冈州边缘地点OM-3进行一项徒步垂直地震剖面实验，以成像垂直于和平行于构造走向的钻孔3公里范围内的构造特征。这将导致更好地定义前缘推力及其相应的幅度异常以及部分原冲断带。由于VSP将使用地面震源在钻孔中获得，因此它们将提供与地面地震数据更好的联系。走走式VSP照亮了钻孔检波器下方的区域，从而成像了钻孔下方和横向远离钻孔的结构。这种横向覆盖将产生振幅与偏移距的信息，这些信息将被用于推断前缘推覆和其他表现出异常振幅的层的流体含量。该合同将支持摩尔博士在俄勒冈州边缘钻探现场3号(OM-3)获得垂直地震剖面(VSP)的努力，该钻探地点将在ODP146段进行钻探。这项实验将提供一个更全面的三维图像的复杂结构特征的吸积棱镜在三公里内的钻孔半径。这将有助于更好地了解棱镜内耦合的结构和水文地质系统。VSP还将允许将地震信息与取心材料和钻井测井数据进行直接比较。

Convergent margin accretionary prisms are structurally complex geological features. This is a proposal to conduct a walkaway Vertical Seismic Profile experiment at Oregon Margin site OM-3 to image the structural features within 3km of the borehole both perpendicular and parallel to structural strike. This should result in better definition of the frontal thrust and its associ- ated amplitude anomalies as well as part of the protothrust zone. Because the VSP's will be acquired in the drill hole using surface seismic sources, they should provide a better tie to surface seismic data. The walkaway VSP illumunates the zone below the borehole geophone, thereby imaging the structure below and laterally away from the drill hole. This lateral coverage will yield amplitude vs offset information, which will be used for inferring fluid contents of the frontal thrust and other layers that exhibit anomalous amplitudes. This award will support Dr. Moore's efforts to obtain Vertical Seismic Profiles (VSP) at the Oregon Margin drill site 3 (OM-3), which will be drilled on ODP Leg 146. This experiment will provide a more comprehensive three dimensional picture of the complex structural features of an accretionary prism within a three kilometer radius of the borehole. This will lead to a better understanding of the coupled structural and hydrogeologic system within the prism. VSP's will also allow direct comparison of seismic information to cored material and borehole logging data.