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

会聚边缘增生棱柱是结构复杂的地质特征。 建议在俄勒冈边缘 OM-3 站点进行无人垂直地震剖面实验，以对钻孔 3 公里内垂直和平行于构造走向的结构特征进行成像。 这应该可以更好地定义锋面推力及其相关的振幅异常以及部分原推力带。 由于 VSP 将使用地面地震源在钻孔中采集，因此它们应该能够更好地与地面地震数据联系起来。 无人值守 VSP 照亮钻孔地震检波器下方的区域，从而对钻孔下方和横向远离钻孔的结构进行成像。 这种横向覆盖将产生振幅与偏移信息，该信息将用于推断正面推力和表现出异常振幅的其他层的流体含量。 该奖项将支持 Moore 博士在俄勒冈边缘钻探点 3 (OM-3) 获取垂直地震剖面 (VSP) 的工作，该钻探点将在 ODP 146 段钻探。该实验将提供更全面的三维图像，显示钻孔半径三公里内的增生棱柱的复杂结构特征。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 还可以将地震信息与岩心材料和钻孔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.