3-D Structure and Tectonic Interpretation of the Cascadia Crust and Subducting Slab from SHIPS and Earthquake Data

题目：基于SHIPS和地震数据的卡斯卡迪亚地壳和俯冲板的三维结构和构造解释[作者：Robert S. Crosson, Kenneth Creager，华盛顿大学]在太平洋西北地区，北美边缘（卡斯卡迪亚俯冲带）下的Juan de Fuca板块的俯冲引起板块边界以及大陆地壳和俯冲板（板）内部的地震。由于人口和地震集中在华盛顿州西部，地震灾害特别令人担忧。2001年2月在普吉特海湾南部地区发生的6.8级地震凸显了胡安·德富卡俯冲板块地震造成的危害。为了进一步了解引起该地区地震的构造过程，有必要对地壳和上地幔的结构都有更好的了解。幸运的是，最近使用可控能量源的地震实验，如SHIPS（普吉特海湾地震灾害）实验，提供了广泛的数据，可用于获得地壳中地震波速度的高分辨率图像，以及俯冲板的反射图像。在本项目中，我们将结合最近几次“活源”地震实验数据和太平洋西北地震仪网络（PNSN）的大量地震观测数据，生成50-60公里深度地壳和上地幔P波速度的高质量大尺度模型。该模型将用于提高我们对PNSN记录的地震位置的认识，并准确地模拟来自俯冲板块的反射波，以便更好地了解板块地震的起源。我们计划为这个项目的模型和解释提供一个互联网分发站点。

Abstract for proposal EAR 0107138 (PH # 12x)Title: 3-D structure and tectonic interpretation of the Cascadia crust and subducting slab from SHIPS and earthquake dataPI's: Robert S. Crosson, Kenneth Creager University of WashingtonIn the Pacific Northwest, subduction of the Juan de Fuca plate beneath the margin of North America (Cascadia subduction zone) causes earthquakes on the plate boundary, as well as within both the continental crust and the subducting plate (slab). Seismic hazards are of particular concern in western Washington State owing to the concentration of population and earthquakes in this region. The hazard due to earthquakes in the subducting Juan de Fuca slab was underscored by the recent magnitude 6.8 earthquake of February 2001 in the southern Puget Sound region. To make progress in understanding the tectonic processes giving rise to earthquakes in this region, it is necessary to gain a better understanding of the structure of both the crust and upper mantle. Fortunately, recent seismic experiments using controlled sources of energy, such as the SHIPS (Seismic Hazards in Puget Sound) experiment, have provided extensive data which can be used to obtain high resolution images of seismic wave speed in the crust, as well as images of the subducting slab from reflections. In this project, we will combine data from several recent "active source" seismic experiments with extensive earthquake observations from the Pacific Northwest seismograph network (PNSN) to produce a high quality but large-scale model of P wave speed of the crust and upper mantle to a depth of 50-60 km. This model will be used to improve our knowledge of the locations of earthquake recorded by the PNSN, and also to accurately model reflected waves from the subducted slab in order to better understand the origin of slab earthquakes. We plan to provide an internet distribution site for our models and interpretations from this project.