Three Dimensional Seismic Velocity Structure of Puerto Rico Virgin Island Microplate

GSTDTAP

项目编号	1722991
	Three Dimensional Seismic Velocity Structure of Puerto Rico Virgin Island Microplate
	Elizabeth Vanacore
主持机构	University of Puerto Rico Mayaguez
项目开始年	2017
	2017-08-15
项目结束日期	2020-07-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	95138(USD)
国家	美国
语种	英语
英文摘要	This project aims to study the structure and tectonics of the Puerto-Rico and Virgin Islands region located at the northeastern border of the Caribbean Plate. In this region, the North American plate is subducting beneath the Caribbean Plate. This interaction between the North American and Caribbean Plates results in significant earthquake activity including the 1918 earthquake and tsunami that devastated western coast of Puerto Rico. Currently, there are multiple tectonic models proposed to describe the interaction between the two plates. However, these models are currently poorly constrained by the available analyzed datasets. The primary goal of this project is to generate high quality seismic velocity images and refined earthquake location data that will provide data based constraints for the regional scientific models and enhance knowledge of the regional earthquake and tsunami hazard. This scientific study will involve two major processes, a relocation of the Puerto Rico Seismic Network earthquake catalog for the years 2015-2017 and a three-dimensional seismic velocity imaging of the region. This time period has been specifically selected to create a synergetic dataset with a current seismic experiment in the Dominican Republic (eastern Hispaniola). The direct data tie between this project and the project in Hispaniola will permit the future combination of the two separate datasets, the creation unified products, and promote scientific partnerships in the region. The first methodology to be applied in this study, earthquake relocation, is the process in which the earthquake locations determined by regional seismic networks and the United States Geological Survey (USGS), which are real-time fast solutions designed to provide information to emergency agencies, are re-examined in detail and refined using more advanced but time consuming computer algorithms as well as additional data that was not available in real-time to generate more accurate locations. The second methodology of this study, travel time tomography, is a method in which a three-dimensional seismic velocity image of the Puerto Rico-Virgin Islands region will be produced in a procedure analogous to how the human body is imaged in a medical CT scan. The imaging to be performed in this study will reveal the regional structure of the Earth's crust and upper mantle. This image combined with the relocated earthquake catalog will provide a robust view of the active tectonic processes that drive the observed regional seismic activity and provide data constraints for future scientific tectonic models. The products generated by this investigation, the relocated earthquake location catalog and seismic velocity imaging, will not only enhance scientific knowledge but also enhance the knowledge of the local earthquake and tsunami hazard. The relocation of local events will permit the identification of the most active faults within the Puerto Rico and Virgin Islands region, especially in Great Southern Puerto Rico Fault Zone and Great Northern Puerto Rico Fault Zone. Consequently, this will aid in the process of updating the Puerto Rico seismic hazard map which has not been revised by the USGS since 2003. The three-dimensional seismic velocity model will be used to determine if the current Puerto Rico Seismic Network one-dimensional velocity model used for earthquake location requires an update. The results of this study will be presented to the general public as short articles in the University of Puerto Rico Mayagüez website and Puerto Rico Seismic Network outreach materials, which impacts hundreds of school children and teachers throughout Puerto Rico every year. This research will also enhance participation of underrepresented students and faculty in the geosciences. The master's student at University of Puerto Rico Mayagüez (a Hispanic Serving Institution) will be funded to conduct the research as part of his/her thesis. The student and principal investigator will also present their research in national meetings and publish in peer-reviewed journals. This study proposes to focus on the seismic structure of the Puerto Rico-Virgin Islands Microplate (PRVIM), one of several proposed microplates in the deformation zone of the northeastern Caribbean margin. Of particular interest is the structure and dynamics of the subducting North American Plate beneath the PRVIM. Multiple tectonic models have been proposed for the dynamics across Hispaniola and the PRVIM. However, these models are currently poorly constrained by the available analyzed datasets. The primary goal of this project is to generate high quality seismic velocity images and refined earthquake location data that will provide data based constraints for the regional scientific models and enhance knowledge of the regional earthquake and tsunami hazard. This scientific study will involve two major processes, a relocation of the Puerto Rico Seismic Network earthquake catalog for the years 2015-2017 and a three-dimensional seismic tomography. This time period has been specifically selected to create a synergetic dataset with a current seismic experiment in the Dominican Republic (eastern Hispaniola). The direct data tie between this project and the project in Hispaniola will permit the future combination of the two separate datasets, the creation unified products, and promote scientific partnerships in the region. This project will generate a relocated event catalog dataset to sharpen the structures that are imaged on the PRVIM via seismicity including the Great Northern Puerto Rico Fault Zone, the subducted North American plate, and possible slab tears in the Mona Passage and Sombrero Seismic Zone. Additionally, a three-dimensional tomography using the FMTOMO program will be performed to image the detailed seismic velocity structure and aid in the identification/corroboration of significant seismic features related to the oblique subduction system. The detailed seismic imaging of this relatively understudied subduction zone will provide insight into the slab structure and dynamics of this oblique margin. The earthquake relocation and tomographic imaging aim to provide a high-resolution picture of the subducting slab structure beneath the PRVIM as well as determine if the two earthquake swarm locations denote slab tears similar to what has been imaged on the south side of the Caribbean Plate by the BOLIVAR project. The high-resolution imaging will also provide seismic constraints for future geodynamic models. In addition to increasing the understanding of the dynamics of oblique subduction zone, the products of this proposal will permit the identification of the most active faults within the PRVIM, especially in Great Southern Puerto Rico Fault Zone and Great Northern Puerto Rico Fault Zone. Consequently, this will aid in the process of updating the Puerto Rico seismic hazard map which has not been revised by the USGS since 2003. The updated three-dimensional seismic velocity model will be used to determine if the current Puerto Rico Seismic Network one-dimensional velocity model used for earthquake requires an update. The results of this study will be presented to the general public as short articles in the University of Puerto Rico Mayagüez website and Puerto Rico Seismic Network outreach materials, which impacts hundreds of school children and teachers throughout Puerto Rico every year. This research will also enhance participation of underrepresented students and faculty in the geosciences. The master's student at University of Puerto Rico Mayagüez (a Hispanic Serving Institution) will be funded to conduct the research as part of his/her thesis. The student and primary investigator will also present their research in national meetings and publish in peer-reviewed journals.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71524
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Elizabeth Vanacore.Three Dimensional Seismic Velocity Structure of Puerto Rico Virgin Island Microplate.2017.