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

9805234DeMets该项目是美国国家科学基金会支持的一项长期努力的延续，目的是测量加勒比海板块的现今运动，并确定沿着伊斯帕尼奥拉和波多黎各附近的加勒比-北美板块边界容纳刚性板块运动的方式。目标包括：(1)利用横跨加勒比海板块的地点的GPS获得的速度建立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)确定加勒比-北美运动如何被分隔伊斯帕尼奥拉和波多黎各附近的两个板块的断层分割，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关于该板块边界的动力学信息；(3)确定西斯帕尼奥拉北部七边形断裂的滑动速率和弹性应变积累水平，该断裂700多年来没有经历过一次大地震，尽管过去几千年来有重大滑动的地质证据。1986年、1994年和1995年跨越加勒比-北美板块边界的GPS网的占领为确定应该解决这些问题的站点位移奠定了基础，现在已经过去了足够的时间，使得现有网络内发生了额外的可测量的位移(范围从10-100毫米不等)。拟议的工作将包括重新占用现有场地以及网络的密集和适度扩展。

9805234DeMetsThis 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.