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

提案摘要0107138(PH#12x)标题：卡斯卡迪亚地壳和俯冲板块的三维结构和构造解释来自船舶和地震数据的PI：罗伯特·S·克罗森，肯尼斯·克里格大学华盛顿分校在太平洋西北部，胡安德·富卡板块在北美边缘(卡斯卡迪亚俯冲带)之下俯冲，在板块边界以及大陆地壳和俯冲板块(板块)内引起地震。由于人口和地震集中在华盛顿州西部地区，地震灾害尤其令人担忧。最近2001年2月在普吉特湾南部地区发生的6.8级地震突显了俯冲的胡安德富卡板块地震造成的危险。为了在理解该地区引发地震的构造过程方面取得进展，有必要更好地了解地壳和上地幔的结构。幸运的是，最近利用受控能源进行的地震实验，例如普吉特湾的地震灾害实验，提供了大量的数据，可以用来获得地壳中地震波速的高分辨率图像，以及从反射中获得俯冲板块的图像。在这个项目中，我们将把最近几次“活动震源”地震实验的数据与太平洋西北地震台网(PNSN)的广泛地震观测相结合，以制作一个高质量但大规模的地壳和上地幔P波速度模型，深度为50-60公里。这个模型将用于提高我们对PNSN记录的地震位置的了解，还将用于准确模拟俯冲板块的反射波，以便更好地了解板块地震的起源。我们计划为我们的模型和这个项目的解释提供一个互联网分发网站。

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.