US-France Cooperative Research: Island Fault Blocks in the Northeastern Caribbean

这个为期三年的美法合作研究项目包括德克萨斯大学奥斯汀分校的Paul Mann和法国萨瓦大学的Jean-Claude Hippolyte。他们将进行断层条纹研究，应用于加勒比海东北部的活动构造问题。他们之前对波多黎各西北部和南部的研究发现，在这些人口稠密的沿海地区，断层陡坡有可能发生地震。在这项建议中，他们继续对人口稠密的波多黎各和别克斯岛（美国领土）、圣克罗伊岛、圣约翰岛、圣托马斯岛、美属维尔京群岛、托尔托拉岛和维尔京戈尔达岛（英国领土）进行断层条纹研究。除波多黎各外，这些岛屿形成出露断块，在深水的阿内加达通道下形成一个主要的伸展或斜滑裂陷盆地综合体。他们的具体目标包括：1)确定受断层影响的晚新生代沉积单元（海上活动断层将用于确定这些断层可能延伸到陆上的可能区域）；2)在采石场和道路切割处发现人工露头，暴露出条状断裂面；3)测量条纹状断层面，确定断层存在的类型和方向；4)考察不同年龄地层单元的断层，建立阿内加达通道开通的断层运动史；5)利用海洋数据更好地了解断层的海上延伸。美国调查员为该项目带来了定量板块重建、陆地地质研究和海洋地球物理研究方面的专业知识。法国在阿尔卑斯山脉、喀尔巴阡山脉和加勒比地区等高度弯曲的造山带构造学方面的专业知识对这一研究进行了补充。该项目将促进对这个人口稠密的加勒比地区地震活动性的了解。该项目由美国国家科学基金会（NSF）和法国国家科学研究中心（CNRS）联合支持。NSF将支持美国研究者的费用，CNRS将支付法国研究者的费用。

0340639MannThis three-year U.S.-France cooperative research project involves Paul Mann at the University of Texas at Austin and Jean-Claude Hippolyte at the Universite de Savoie in France. They will perform fault striation studies applied to problems of active tectonics in the northeastern Caribbean. Their previous studies of northwestern and southern Puerto Rico identified fault scarps with earthquake potential in these densely populated coastal regions. In this proposal, they continue fault striation studies on the densely populated islands of Puerto Rico and Vieques (U.S. territory), St. Croix, St. John, St. Thomas, U.S.Virgin Islands, Tortola and Virgin Gorda (British territories). Except for Puerto Rico, these islands form emergent fault blocks framing a major extensional or oblique-slip rifted basin complex underlying the deep-water Anegada Passage.Their specific objectives include: 1) identifying late Cenozoic sedimentary units affected by faulting (offshore, active faults will be used to target likely areas where these faults might extend onshore); 2) finding manmade outcrops in rock quarries and along road cuts that expose striated fault planes; 3) measuring striated fault surfaces to determine the types and orientations of faults present; 4) examining faults in different aged stratigraphic units, establish a fault kinematic history for the opening of the Anegada Passage; and 5) using marine data to better understand the offshore extensions of faults. The U.S. investigator brings to the project expertise in quantitative plate reconstructions, land based geological studies and marine geophysical studies. This is complemented by French expertise on the tectonics of highly curved orogenic belts including the Alps, the Carpathians and the Caribbean. The project will advance understanding of seismicity in this densely populated Caribbean region.The project is jointly supported by the National Science Foundation (NSF) and the Centre National de la Recherche Scientifique (CNRS). NSF will support the expenses of the U.S. investigator and the CNRS covers expenses of the French investigator.