Collaborative Research: Active, Upper Plate Deformation in Response to Migration of the Panama Triple Junction, Pacific Coast, Panama and Costa Rica

合作研究：巴拿马三重交界处、太平洋沿岸、巴拿马和哥斯达黎加迁移引起的活跃上部板块变形

• 批准号: 0737943
• 负责人: Thomas Gardner
• 金额: $ 9.73万
• 依托单位: Trinity University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0737943&HistoricalAwards=false
• 关键词: Collaborative; Research; Active; Upper; Plate

This multidisciplinary study of forearc evolution examines the short term (years) and long term (thousands to millions of years) patterns of strain in the upper plate of a subduction zone that straddles the subducting Panama Fracture Zone, an active transform fault. The project goals are to test several hypotheses, including: 1) upper plate deformation is primarily a consequence of indentation tectonics related to Cocos Ridge collision; 2) the Fila Costena thrust belt is propagating laterally into Panama with the migration of the Panama Triple Junction; 3) the velocity field in the upper plate reflects Cocos Ridge collision, including shortening across the Fila Costena, shear/uplift across the onshore projection of the Panama Fracture Zone, and the elastic strain associated with the earthquake cycle. The research team is using structural analyses, Quaternary geologic mapping and dating, and geodetic GPS and modeling studies in an effort to integrate a long-term record of deformation with short-term indicators of kinematics to allow for assessment of rates and styles of deformation of the upper plate. Intersection of the leading edge of the Fila Costena thrust belt with a volcanic debris fan provides excellent timelines to constrain deformation. Radiocarbon and Optically Stimulated Luminescence dating of a superb flight of marine terraces on the Burica Peninsula yield an excellent record of late Quaternary deformation of the peninsula. Geodetic research of strain partitioning will determine the spatial and temporal patterns of short-term elastic strain.Subduction zones are sites of the largest earthquakes on earth, with buildup of elastic strain along the plate boundary until release of this stored energy during earthquakes. By combining short-term and long-term indicators of deformation in the upper plate of the Middle America plate boundary, the elastic or recoverable strain that leads to earthquakes as well as the permanent strain that averages the effects of many earthquakes can be evaluated. This project specifically addresses the coupling attributes of the plate boundary in southern Costa Rica and southwestern Panama, with an assessment of the earthquake hazard of these regions. The project, under the direction of principal investigators from Pennsylvania State University and Trinity University, involves graduate and undergraduate students and scientific collaborations with Costa Rican and Panamanian researchers. The project is supported by the NSF Earth Sciences Division Tectonics Program and the NSF Office of International Science and Engineering.

这种弧前演化的多学科研究探讨了短期（年）和长期（数千至数百万年）的俯冲带，横跨俯冲巴拿马断裂带，一个活跃的转换断层的上板的应变模式。该项目的目标是检验几个假设，包括：1）上板块变形主要是与科科斯海岭碰撞有关的压痕构造的结果; 2）Fila Costena冲断带随着巴拿马三联点的迁移横向扩展到巴拿马; 3）板块上部的速度场反映了科科斯海岭的碰撞，包括穿过Fila Costena的缩短，剪切/隆起横跨巴拿马断裂带的陆上投影，以及与地震周期相关的弹性应变。研究小组正在利用结构分析、第四纪地质测绘和测年、大地测量全球定位系统和建模研究，努力将长期变形记录与短期运动学指标结合起来，以便评估上板块的变形速率和类型。Fila Costena冲断带前缘与火山碎屑扇的交叉点为约束变形提供了极好的时间线。对布里卡半岛上的一片极好的海洋阶地进行放射性碳和光释光测年，获得了半岛晚第四纪变形的极好记录。应变分解的大地测量学研究将确定短期弹性应变的空间和时间模式。俯冲带是地球上最大地震的发生地，弹性应变沿着板块边界积累，直到地震时释放这种储存的能量。通过结合中美洲板块边界上板块的短期和长期变形指标，可以评估导致地震的弹性或可恢复应变以及平均许多地震影响的永久应变。该项目具体涉及哥斯达黎加南部和巴拿马西南部板块边界的耦合属性，并对这些地区的地震危险性进行评估。该项目由宾夕法尼亚州立大学和Trinity大学的主要研究人员指导，涉及研究生和本科生以及与哥斯达黎加和巴拿马研究人员的科学合作。该项目由NSF地球科学部构造计划和NSF国际科学与工程办公室支持。