权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A Synoptic View of the Formation, Evolution, and Shallow Subduction of the Juan de Fuca and Gorda Plates

胡安德富卡板块和戈尔达板块的形成、演化和浅俯冲概况

基本信息

批准号：
1537868
负责人：
Michael Ritzwoller
金额：
$ 27.45万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2019-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1537868&HistoricalAwards=false
关键词：
Synoptic View Formation Evolution Shallow

项目摘要

The installation of a large array of ocean bottom and land seismometers for the Cascadia Initiative provides unprecedented coverage of the Juan de Fuca and Gorda plates, offshore, and in Cascadia, onshore. The array makes it possible to study the structure and processes of an oceanic plate from its formation at the spreading center, through its evolution, and ultimate subduction beneath the continent. The scientific goals are to image the magma producing regions beneath the Juan de Fuca and Gorda spreading centers, to understand the thermal evolution of an oceanic plates and to determine how the plate deforms over time. In the region where the plate begins to bend downward at the onset of subduction, special attention will devoted to the Locked and Transition Zones of the major fault separating the downgoing plate from the over-riding plate. The new 3-D model that will emerge will encompass much of the locked zone that fails in major earthquakes across Cascadia, which pose perhaps the greatest seismic hazard to the US.This study focuses on the development of a 3D model of the crust and uppermost mantle to a depth of between 60 km and 100 km, depending on the maximum period of observation. The model will encompass isotropic structures as well as the radial (or polarization) and azimuthal anisotropy of shear velocities. The work will be based primarily on Rayleigh and Love wave dispersion data derived from ambient noise and earthquakes, which will be interpreted within the framework of a Bayesian Monte Carlo inversion to generate a distribution of accepted models from which uncertainties will be estimated. Receiver functions and Rayleigh wave horizontal/vertical amplitude ratios will be assimilated in the inversion wherever practical. The seismological models, and the data used to construct them, will be archived and shared with the broader geoscience community. High level data products such as dispersion maps, 3-D models, receiver functions, other surface wave observables like H/V ratios, and research codes are delivered through dynamically updated, internet-accessible databases. The proposal will also support one graduate student.

为卡斯卡迪亚倡议安装了一大批海底和陆地地震仪，使胡安·德富卡和戈尔达板块在海上以及卡斯卡迪亚在陆上的覆盖范围达到前所未有的程度。该阵列使研究海洋板块的结构和过程成为可能，从它在扩张中心的形成，到它的演化，以及最终在大陆之下的俯冲。科学目标是对Juan de Fuca和Gorda扩张中心下方的岩浆生成区域进行成像，以了解海洋板块的热演化，并确定板块如何随时间变形。在板块俯冲开始时开始向下弯曲的区域，将特别注意分离下行板块和上覆板块的主要断层的锁定带和过渡带。新的3-D模型，将出现将包括大部分的锁定区，在整个卡斯卡迪亚，这可能是最大的地震危险，美国的大地震失败。这项研究的重点是地壳和上地幔的3D模型的发展深度之间的60公里和100公里，这取决于观察的最大期限。该模型将包括各向同性结构以及径向（或偏振）和方位角各向异性的剪切速度。这项工作将主要基于从环境噪声和地震中获得的瑞利波和洛夫波频散数据，这些数据将在贝叶斯蒙特卡罗反演的框架内进行解释，以生成可接受的模型分布，并从中估计不确定性。接收器函数和瑞利波水平/垂直振幅比将在可行的情况下在反演中被同化。地震学模型以及用于构建这些模型的数据将被存档，并与更广泛的地球科学界共享。高层次的数据产品，如色散图，三维模型，接收器功能，其他表面波观测值，如H/V比，和研究代码是通过动态更新，互联网访问的数据库提供。该提案还将支持一名研究生。