Imaging the Eastern Trans-Mexican Volcanic Belt

跨墨西哥东部火山带成像

• 批准号: 1645063
• 负责人: Robert Clayton
• 金额: $ 17.86万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-01 至 2020-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1645063&HistoricalAwards=false
• 关键词: Imaging; Eastern; Trans; Mexican; Volcanic

The abrupt end of the Trans-Mexican Volcanic Belt (TMVB) in central Mexico marks a dramatic change in the subduction system that defines the western margin of North America. To the west, the subducted slab is horizontal at 45 km depth until it reaches the TMVB (at the latitude Mexico City) where it plunges into the mantle to a depth of 500 km. To the east the slab descends with a dip of 30-degrees to a depth of 150 km where it is cut off by an unexplained structure. The goal of this study is to understand why these systems are different and how they function together. The larger goal is to find a unified model for the subduction system from the western coast of the United States to Central America. Determining the tectonic structure in this region is important, because it is a transition point in that model. The study will also continue cooperative studies with Mexican scientists that have been ongoing for the past decade.We propose to make a detailed image the structure beneath the eastern end of the TMVB, using receiver functions to map subsurface interfaces in the structure. This method uses the conversion of P-waves to S-waves to determine the location and contrast of the interfaces. To determine the velocity structure of the region we will use surface waves from earthquakes and ambient noise correlations. Both of these techniques can also be used to estimate the anisotropic behavior of the subsurface, which can be used to determine the present and past flow of material. The goal is to integrate the structure and flow into models that can be used to explain the tectonic evolution of this area. The study will exploit several existing seismic datasets in the region, plus a current Mexican project (GECO) that is operating a dozen seismic stations in the region that we plan to image.

墨西哥中部跨墨西哥火山带（TMVB）的突然结束标志着定义北美西缘的俯冲系统发生了巨大变化。向西，俯冲板片在 45 公里深度处呈水平状态，直至到达 TMVB（位于墨西哥城纬度），并在此深入地幔 500 公里深度。在东边，板块以 30 度的倾角下降到 150 公里的深度，并被一个无法解释的结构切断。本研究的目的是了解这些系统为何不同以及它们如何协同运作。更大的目标是找到从美国西海岸到中美洲的俯冲系统的统一模型。确定该地区的构造结构很重要，因为它是该模型的过渡点。该研究还将继续与墨西哥科学家在过去十年中进行的合作研究。我们建议对 TMVB 东端下方的结构进行详细成像，使用接收器函数来绘制结构中的地下界面。该方法使用 P 波到 S 波的转换来确定界面的位置和对比度。为了确定该区域的速度结构，我们将使用地震表面波和环境噪声相关性。这两种技术也可用于估计地下的各向异性行为，从而可用于确定当前和过去的材料流动。目标是将结构和流量整合到可用于解释该地区构造演化的模型中。该研究将利用该地区现有的几个地震数据集，以及当前的墨西哥项目 (GECO)，该项目正在我们计划成像的地区运行十几个地震站。

项目成果

Imaging the Eastern Trans-Mexican Volcanic Belt With Ambient Seismic Noise: Evidence for a Slab Tear

用环境地震噪声对跨墨西哥东部火山带进行成像：板片撕裂的证据

• DOI: 10.1029/2018jb015783
• 发表时间: 2018-09
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Castellanos, Jorge C.;Clayton, Robert W.;Pérez
• 通讯作者: Pérez

Crustal structure variations in south-central Mexico from receiver functions

接收函数显示墨西哥中南部地壳结构的变化

• DOI: 10.1093/gji/ggz434
• 发表时间: 2019-10
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Rodríguez;Pérez;Montealegre;Clayton, Robert W.;Cabral
• 通讯作者: Cabral