Collaborative Research: Seismic Hazard, Lithosphere Hydration, and Double-Verging Structure of the Puerto Rico Subduction Zone: A Seismic Reflection and Refraction Perspective

合作研究：波多黎各俯冲带的地震灾害、岩石圈水化和双边缘结构：地震反射和折射视角

• 批准号: 2309736
• 负责人: Elizabeth Vanacore
• 金额: $ 8.59万
• 依托单位: University of Puerto Rico Mayaguez
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309736&HistoricalAwards=false
• 关键词: Collaborative; Research; Seismic; Hazard; Lithosphere; Collaborative; Research; Seismic; Hazard; Lithosphere

The Puerto Rico Trench (PRT) poses major earthquake and tsunami hazards. Tsunamis generated at this subduction zone may also impact the U.S. East Coast. This project supports land and sea seismic experiments across the PRT and Puerto Rico. The experiments will define the detailed seismic structure of the PRT, advance our understanding of the PRT, and improve hazard assessment. The project consists of: (1) Three wide-angle seismic reflection/refraction profiles using ocean bottom seismometers (OBS); (2) Seven multichannel seismic (MCS) reflection profiles, two parallel to and inland from the trench, and five across the trench. (3) An array of 100 short-period land nodal seismometers deployed across the Puerto Rico island. The project will provide support for training several graduate students and an early career scientist, as well as research opportunities for faculty and students at a minority serving institution.This project supports an active-source seismic experiment across the Puerto Rico Trench (PRT), its outer rise, and across the Puerto Rico island arc. The PRT is a highly oblique subduction zone, where old Atlantic plate subducts under the Caribbean plate at a slow rate. The PRT is associated with anomalous and unexplained characteristics, such as the widest trench (below 6,000 m), the lowest gravity anomaly on Earth, and anomalous subsidence of the north coast of Puerto Rico. This project will acquire, analyze, and interpret multiple types of data: Three wide-angle seismic reflection/refraction profiles across the PRT with OBSs, with one of the lines extending to south of the Puerto Rico island and including an array of land nodal seismometers deployed across the Puerto Rico island; seven MCS reflection profiles, two parallel and five perpendicular to the PRT axis; and multibeam bathymetry, 3.5 kHz sub-bottom profiler, gravity, and magnetics. The experiments are designed to address three key questions: (1) What is the shallow geometry of the subducting slab and its lateral continuity along the 500-km section of the trench? (2) What are the degree and spatial extent of hydration of the Atlantic lithosphere entering the Puerto Rico Trench? (3) Does oceanic bivergent thrust system represent double-sided subduction or a crustal retro-wedge of one-sided subduction? The integrated seismic experiments, together with the other ancillary geophysical datasets, will produce two-dimensional seismic reflection images, P-wave and S-wave travel-time tomography 2-D models, and gravity-derived density models of the study region. These results are expected to significantly advance our understanding of the above scientific questions and assessment of the PRT seismic and tsunami hazard.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

波多黎各沟渠（PRT）构成了主要地震和海啸危害。在这个俯冲带产生的海啸也可能影响美国东海岸。该项目支持PRT和波多黎各的土地和海震实验。实验将定义PRT的详细地震结构，提高我们对PRT的理解并改善危害评估。该项目由：（1）使用海底地震仪（OBS）的三个广角地震反射/逆转曲线； （2）七个多通道地震（MCS）反射曲线，两个与沟渠平行于内陆，五个在沟槽中。 （3）在波多黎各岛上部署了一组100个短期土地淋巴结地震米。该项目将为培训几名研究生和早期职业科学家提供支持，并为少数服务机构的教职员工和学生提供研究机会。该项目支持波多黎各Rico Trench（PRT）的主动源地震实验（PRT），其外部上升，以及波多黎各Ricco Island Arc。 PRT是一个高度倾斜的俯冲带，在加勒比海板下方的旧大西洋板块以缓慢的速度。 PRT与异常和无法解释的特征有关，例如最宽的沟渠（低于6,000 m），地球上的最低重力异常以及波多黎各北部海岸的异常沉降。该项目将获取，分析和解释多种类型的数据：带有OBS的三个广角地震反射/倒数曲线，其中一条线延伸至波多黎各岛以南，其中包括一系列在波多黎各岛上部署的地面淋巴结震荡者；七个MC反射曲线，两个平行和五个垂直于PRT轴；和多片测深，3.5 kHz的子底剖面，重力和磁化剂。这些实验旨在解决三个关键问题：（1）俯冲板的浅几何形状及其沿沟渠500公里的横向连续性是什么？ （2）进入波多黎各沟渠的大西洋岩石圈水合的程度和空间程度是多少？ （3）海洋双螺旋推力系统是否代表双面俯冲或单侧俯冲的地壳曲折？综合的地震实验以及其他辅助地球物理数据集将产生二维地震反射图像，P-波和S波旅行时间层析成像2-D模型以及研究区域的重力衍生密度模型。这些结果有望大大提高我们对上述科学问题的理解，并评估PRT地震危险和海啸危害。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛影响的评估标准来评估值得支持的。