CAREER: Convergence of Space Geodesy in Plate Boundary Research and Geoscience Education

本项目研究了斜辐合和应变划分的运动学和力学，以及脊碰撞对上板块变形俯冲带的地球动力学影响，以更好地了解弧前地体的形成。本研究将新的和现有的GPS数据、地震数据（地震位置和质心矩张量解）和地质观测数据与数值模型相结合，旨在：1)估算板间逆冲和弧前走滑断层耦合的震级和空间变异性；2)确定弧前运动速率；3)对应变分配和脊碰撞的相关力进行分析。这项研究的重点是两个辐合边缘，中美洲南部（科科斯-纳斯卡-加勒比板块：巴拿马）和南美洲北部（纳斯卡-南美板块：厄瓜多尔）。在中美洲南部，科科斯板块辐合是正交的，科科斯脊与边缘碰撞。这里没有发育良好的边缘平行弧前走滑断层，认为弧前向西北和东南方向的运动是由脊碰撞驱动的。在南美洲北部，纳斯卡板块辐合是倾斜的，卡内基山脊与边缘碰撞。边缘平行弧前走滑断层容纳了北安第斯地块的东北运动。将在巴拿马和厄瓜多尔建立GPS网络，以更好地约束科科斯和纳斯卡板块与中美洲地峡（加勒比板块）和南美洲板块相互作用引起的地表变形的运动学。该职业奖的教育部分：1)通过开发六个板块构造电子表格模块（其有效性将被评估）来提高地球科学的定量素养；2)通过UNAVCO学生固体地球科学研究经验和宾夕法尼亚州立大学高级本科研究中心经验项目，为本科生提供国际研究和教育经验；3)为研究生提供国际研究和教育经验；4)在板块边界上形成新课程的基础。俯冲带板块边界释放出最大的弹性能量，产生大地震和毁灭性的海啸。在俯冲带，板块之间的收敛与板块边缘不是正交的，以及海底脊碰撞的地方，板块之间的相互作用可能是复杂的。在这种情况下，上覆板块的运动可以分为大逆冲运动和走滑运动。本研究旨在通过结合使用GPS数据确定巴拿马和厄瓜多尔两个例子中控制这种行为的力量，这将改进运动矢量，并建模以约束发挥作用的力量。学生将通过使用数据的课堂活动和国际研究经验参与该项目。这项研究的结果将有助于了解中美洲的地震灾害。该研究项目由地球科学部的构造与教育与人力资源项目和国际科学与工程办公室美洲项目支持。

This project investigates the kinematics and mechanics of oblique convergence and strain partitioning and the geodynamic affects of ridge collision on upper plate deformation subduction zones to gain a better understanding of the formation of fore-arc terranes. This study integrates new and existing GPS data, seismic data (earthquake locations and centroid moment tensor solutions), and geologic observations with numerical models to: 1) estimate the magnitude and spatial variability of coupling on interplate thrust and fore-arc strike-slip faults; 2) determine the rate of fore arc motion; and 3) conduct an analysis of the forces associated with strain partitioning and ridge collision. The study focuses on two convergent margins, southern Central America (Cocos-Nazca-Caribbean plates: Panama) and northern South America (Nazca-South America plates: Ecuador). In southern Central America, Cocos plate convergence is orthogonal and the Cocos Ridge collides with the margin. There is no well-developed margin parallel fore-arc strike-slip fault here and it has been suggested that fore-arc motion to the northwest and southeast is driven by ridge collision. In northern South America, Nazca plate convergence is oblique and the Carnegie Ridge collides with the margin. Margin parallel fore-arc strike-slip faults accommodate northeast motion of the North Andean block. GPS networks will be established in Panama and Ecuador to better constrain the kinematics of surface deformation caused by the interaction of the Cocos and Nazca plates with the Central American isthmus (Caribbean plate) and South American plate. The educational component of this CAREER award : 1) enhances quantitative literacy in the geosciences through the development of six plate tectonics spreadsheet modules whose effectiveness will be assessed; 2) provides international research and education experiences for undergraduate students through the UNAVCO Research Experience in Solid Earth Science for Students and the Penn State University Center for Advanced Undergraduate Studies Experience programs; and 3) provides international research and education experiences for graduate students; 4) forms the basis for new courses on plate boundaries.Subduction zone plate boundaries release the greatest amount of elastic energy producing great earthquakes and devastating tsunamis. The interaction of plates at subduction zones can be complex where convergence between plates is not orthogonal to the plate margin and where submarine ridges collide. In these cases, motion in the overriding plate can be partitioned between megathrust and strike-slip motion. This study aims determine the forces that control this behavior in two examples in Panama and Ecuador through a combined use of GPS data, which will refine the motion vectors, and modeling to constrain the forces at play. Students will be engaged in the project through classroom activities using the data and through international research experiences. The results of this study will assist in understanding earthquake hazards in Central America.This research project is supported by the Earth Sciences Division's Tectonics and Education & Human Resources Programs and the Office of International Science and Engineering Americas Program.