Collaborative Research: A GPS Study of Caribbean Plate Kinematics and Distributed Deformation Between the Caribbeanand North American Plates

[806464]曼：这个项目是由美国国家科学基金会资助的长期努力的延续，旨在测量加勒比板块的现今运动，并确定在伊斯帕尼奥拉岛和波多黎各附近的加勒比-北美板块边界上，刚性板块运动的适应方式。目标包括：(1)利用从横跨加勒比板块的地点获得的gps速度构建加勒比板块运动学模型，并使用相同的速度测试加勒比板块的非刚性；(2)确定在伊斯帕尼奥拉岛和波多黎各附近分离两个板块的断层如何分割加勒比-北美运动，并最终通过模拟弹性应变和从速度场中提取块体旋转来提取该板块边界的动力学信息；(3)测定了伊斯帕尼奥拉北部七层断层的滑动速率和弹性应变积累水平，该断层在过去的几千年里尽管有地质证据表明存在明显的滑动，但在700多年里没有经历过一次大地震。1986年、1994年和1995年跨越加勒比海-北美板块边界的GPS网络的工作为确定应该解决这些问题的地点位移奠定了基础，现在已经过去了足够的时间，因此在现有网络中已经发生了额外的可测量位移（范围从10-100毫米）。拟议的工作将包括重新占用现有场地，以及密集化和适度扩大网络。

9806464MannThis project is a continuation of a long-term NSF-sponsed effort to measure the present-day motion of the Caribbean plate and to determine the manner in which rigid plate motion is accommodated along the Caribbean-North America plate boundary near Hispaniola and Puerto Rico. The objectives include: (1) Construction of a Caribbean plate kinematic model using GPS-derived velocities from sites that span the Caribbean plate and to use the same velocities to test for non-rigidity of the Caribbean plate; (2) determination of how Caribbean-North America motion is partitioned by the faults that separate the two plates in the vicinity of Hispaniola and Puerto Rico, and ultimately, to extract information about the dynamics of this plate boundary by modeling elastic strain and extracting block rotations from the velocity field; (3) determination of the slip rate and level of elastic strain accumulation along the Septentrional fault in northern Hispaniola, which has not experienced a major earthquake in more than 700 years despite geologic evidence for significant slip over the past several thousand years. Occupations in 1986, 1994, and 1995 of a GPS network spanning the Caribbean-North America plate boundary have set the stage for determinations of site displacements that should resolve these questions, and sufficient time has now elapsed so that additional measurable (ranging from 10-100 millimeters) displacements have occurred within the exisiting network. The proposed work will include a reoccupation of the existing sites as well as densification and modest expansion of the network.