Collaborative Research: Mapping the Rivera Subduction Zone

合作研究：绘制里维拉俯冲带地图

• 批准号: 0335782
• 负责人: Stephen Grand
• 金额: --
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0335782&HistoricalAwards=false
• 关键词: Collaborative; Research; Mapping; Rivera; Subduction

The investigators plan to deploy fifty broadband seismic instruments throughout the Jalisco and Colima provinces in Mexico. This region of Mexico is being underthrust by the Rivera microplate and has witnessed the largest earthquake in Mexican history. The subduction of the Rivera plate has also resulted in the overriding plate, the Jalisco block, separating from the rest of Mexico along two perpendicular grabens. The Jalisco block is also volcanically active with the Colima volcano unusually close to the trench. This region is a type example of the processes that can occur when a ridge meets a subduction zone. The tectonics of the region has been postulated to be due to the interaction of the Rivera plate and the overriding Jalisco block but little geophysical data exist to truly understand the subsurface interactions. In this project researchers will image the geometry of the Rivera plate at depth including a search for tears with the adjacent Cocos plate or evidence of breaking up of the Rivera plate at depth, both of which have been postulated. In this work tomographic imaging tools as well as receiver function analysis will be employed. Careful mapping of the slab surface as well as the locations and mechanisms of earthquakes in the region will provide constraints on the region of coupling between the Jalisco and Rivera plates. This will provide useful information for the ongoing GPS projects funded by NSF in this region that will ultimately help with hazard analysis. The investigators will also attempt to image the mantle wedge to better understand the volcanism in the region. Using shear wave splitting we hope to understand mantle flow beneath the Jalisco block. This study should have broader impact in understanding the evolution of plate boundaries when ridges interact with subduction zones. This has occurred in the geologically recent past off the coast of California and northern Mexico. This research includes a substantial international collaboration with Mexican colleagues from several institutions.This project is co-sponsored by the Americas Program in the Office Of International Science And Engineering.--

研究人员计划在墨西哥哈利斯科州和科利马州部署 50 个宽带地震仪器。墨西哥的这个地区正受到里维拉微板块的逆冲，见证了墨西哥历史上最大的地震。里维拉板块的俯冲也导致了压倒一切的板块——哈利斯科板块，沿着两个垂直的地堑与墨西哥其他地区分开。哈利斯科地区的火山也很活跃，科利马火山异常靠近海沟。该区域是山脊与俯冲带相遇时可能发生的过程的典型示例。该地区的构造被认为是由于里维拉板块和哈利斯科地块的相互作用造成的，但几乎没有地球物理数据来真正了解地下相互作用。在这个项目中，研究人员将对里维拉板块深处的几何形状进行成像，包括寻找邻近科科斯板块的撕裂或里维拉板块在深处破裂的证据，这两者都是假设的。在这项工作中，将使用断层扫描成像工具以及接收器功能分析。仔细绘制板块表面以及该地区地震的位置和机制将为哈利斯科板块和里维拉板块之间的耦合区域提供约束。这将为该地区 NSF 资助的正在进行的 GPS 项目提供有用的信息，最终有助于危害分析。研究人员还将尝试对地幔楔进行成像，以更好地了解该地区的火山活动。我们希望利用剪切波分裂来了解哈利斯科地块下方的地幔流。这项研究应该对理解洋脊与俯冲带相互作用时板块边界的演化产生更广泛的影响。这种情况在地质学上最近发生在加利福尼亚州和墨西哥北部海岸附近。这项研究包括与来自多个机构的墨西哥同事进行的大量国际合作。该项目由国际科学与工程办公室美洲项目共同赞助。