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Building a continent: Integration of surface geology, rock physics, and seismic observations to investigate the tectonic history of the contiguous United States

构建大陆：整合地表地质学、岩石物理学和地震观测来研究美国本土的构造历史

基本信息

批准号：
1735890
负责人：
Vera Schulte-Pelkum
金额：
$ 28.42万
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：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1735890&HistoricalAwards=false
关键词：
Building continent Integration surface geology

项目摘要

The North American continent formed over billions of years via the collision of continental fragments and the rifting apart of larger continents. Geologists can read some of this history by looking at rocks exposed at the Earth's surface that were deformed in the past. The aim of this project is to extend this ability below the Earth's surface. While buried rocks cannot be seen and mapped directly, they are constantly traversed by seismic waves from earthquakes around the world. These waves are imprinted with information on the rocks they travel through before reaching the Earth's surface. We combine mapped rock deformation at the surface with seismic information from the subsurface in order to find out how to extract the imprinted information from the seismic data. The information can then be used to map how the Earth's crust was deformed. The project advances knowledge of Earth science by allowing us to read the record of past geological processes beneath the surface. Because current geological processes also deform rocks, the method can also be used to map the roots of earthquake-generating faults, which is useful for estimates of seismic hazard. The rock characteristics investigated in this process are also relevant to mapping geological resources. Additionally, accurate knowledge of the imprint of rock fabrics on the seismic signal enables us to avoid biases in other uses of the seismic data, such as for location and characterization of natural and human-made seismic sources.A stated goal of the EarthScope program is to derive constraints on the deformation history of the continent. This project aims to bridge the scales from microstructural rock fabrics measured in the laboratory, to deformation structures mapped on outcrop exposures, and to rock fabrics causing seismic anisotropy at km-scale seismic wavelengths. Project components are 1) integration of seismic anisotropy observations from multiple techniques and seismic networks, 2) contribution of existing digital structural data sets containing foliations, lineations, and mapped major ductile and brittle faults to existing EarthCube-funded and U. S. Geological Survey-held databases as well as calculation of bulk elasticity tensors from ~1:100,000 scale maps to hand samples and 3) synthesis and joint interpretation of seismic observations and structural data extracted from EarthCube-funded databases using straightforward correlations as well as an explicit scaling from elastic tensors representative of rock types to geological foliation maps to seismic wavelength-scale anisotropy.The ability to relate crustal seismic anisotropy to the strain history of the crust requires 1) a representative catalog of elastic properties of crustal rocks and how they average at scales of seismic wavelengths and 2) a compilation of major structural parameters such as orientations of dominant rock fabrics (foliation and lineation) in metamorphic and igneous rocks and their internal coherence in unique domains, as well as orientations of more discrete features such as fault zones, in order to enable quantitative comparisons to anisotropy measured seismically. The proposed work will centralize existing compilations and make them widely available online.

北美大陆是在数十亿年的时间里，通过大陆碎片的碰撞和较大大陆的断裂而形成的。地质学家可以通过观察暴露在地球表面的岩石来了解一些历史，这些岩石在过去发生了变形。该项目的目的是将这种能力扩展到地球表面以下。虽然埋藏的岩石无法直接看到和绘制地图，但它们不断被世界各地地震的地震波穿过。这些波在到达地球表面之前，在它们所穿过的岩石上留下了信息。我们将联合收割机映射的地表岩石变形与来自地下的地震信息相结合，以便找出如何从地震数据中提取印记信息。这些信息可以用来绘制地壳是如何变形的。该项目通过让我们阅读地表下过去地质过程的记录来推进地球科学的知识。由于目前的地质过程也使岩石变形，因此该方法也可用于绘制地震发生断层的根源，这对估计地震危险性很有用。在这一过程中调查的岩石特征也与地质资源测绘有关。此外，准确了解岩石组构对地震信号的影响，使我们能够避免在地震数据的其他用途中出现偏差，例如用于天然和人为地震源的定位和表征。EarthScope计划的一个既定目标是获得对大陆变形历史的约束。该项目旨在将实验室测量的微结构岩石组构与露头暴露上绘制的变形结构以及在千米级地震波长下引起地震各向异性的岩石组构的尺度联系起来。项目的组成部分是：1）整合来自多种技术和地震网络的地震各向异性观测，2）将现有的数字结构数据集（包含叶理、线理和绘制的主要韧性和脆性断层）贡献给现有的EarthCube资助和U. S.地质调查局拥有的数据库以及从~1：100,将地壳地震各向异性与地壳应变历史联系起来的能力需要：1）一个地壳岩石弹性性质的代表性目录，以及它们在地震波长尺度上的平均值; 2）主要结构参数的汇编，如变质岩和火成岩中主要岩石组构（叶理和线理）的取向及其在独特域中的内部一致性，以及断层带等更离散特征的取向，以便能够与地震测量的各向异性进行定量比较。拟议的工作将集中现有的汇编，并在网上广泛提供。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Imaging the Tectonic Grain of the Northern Cordillera Orogen Using Transportable Array Receiver Functions

DOI：
10.1785/0220200182
发表时间：
2020-11
期刊：
Seismological Research Letters
影响因子：
3.3
作者：
V. Schulte‐Pelkum;J. Caine;James V. Jones;T. Becker
通讯作者：
V. Schulte‐Pelkum;J. Caine;James V. Jones;T. Becker

Tectonic Inheritance During Plate Boundary Evolution in Southern California Constrained From Seismic Anisotropy

DOI：
10.1029/2021gc010099
发表时间：
2021-08
期刊：
Geochemistry
影响因子：
3.7
作者：
V. Schulte‐Pelkum;T. Becker;W. Behr;M. Miller
通讯作者：
V. Schulte‐Pelkum;T. Becker;W. Behr;M. Miller

Confronting Solid‐State Shear Bias: Magmatic Fabric Contribution to Crustal Seismic Anisotropy

面对固态剪切偏差：岩浆组构对地壳地震各向异性的贡献

DOI：
10.1029/2022gl102399
发表时间：
2023
期刊：
Geophysical Research Letters
影响因子：
5.2
作者：
Frothingham, Michael G.;Mahan, Kevin H.;Schulte‐Pelkum, Vera;Goncalves, Philippe;Zucali, Michele
通讯作者：
Zucali, Michele

Don't judge an orogen by its cover: Kinematics of the Appalachian décollement from seismic anisotropy

不要以地貌来判断造山带：地震各向异性的阿巴拉契亚山脉运动学

DOI：
10.1130/g50323.1
发表时间：
2022
期刊：
Geology
影响因子：
5.8
作者：
Frothingham, Michael G.;Schulte-Pelkum, Vera;Mahan, Kevin H.;Merschat, Arthur J.;Mather, Makayla;Gomez, Zulliet Cabrera
通讯作者：
Gomez, Zulliet Cabrera

Tectonic Inheritance With Dipping Faults and Deformation Fabric in the Brittle and Ductile Southern California Crust