Collaborative Research: Unraveling distributed deformation during early-stage rifting in the Western and Southwestern African Rifts

裂谷作用是板块构造的基本过程之一，它导致大陆的解体和新洋盆的形成。东非是当今大陆裂谷的主要例子。虽然一些研究已经对东非北部更古老、更发达的裂谷产生了重要的见解，但由于较年轻的西部和西南裂谷系统的数据稀少，我们对裂谷如何开始和发展的认识存在重大差距。特别是，与早期裂谷有关的地面变形在整个区域延伸到多大程度，以及在没有地震的情况下可能发生多大程度的变形，都存在很大的不确定性。该项目将结合来自全球导航卫星系统/全球定位系统数据的地面变形数据、合成孔径雷达干涉测量(InSAR)和永久性地震仪来测量和调查跨越西部和西南裂谷的早期裂谷运动学。这些结果将提高我们对该地区基本构造过程和地震危险性估计的理解。该项目将为学生提供本科生和研究生的研究机会，发展国际研究合作，并通过在美国和非洲的中学开展外联活动，以及通过国内研讨会和访问美国研究机构提供数据处理和分析方面的培训机会，为科学和技术能力建设做出贡献。该项目的总体目标是测试现有的裂谷如何分布在中非东非裂谷西段和西南段周围隆起和断层地区的模型，并确定活跃裂谷的哪一部分是无地震的。为实现这一目标，将在这一正在研究的地区增加大地测量，包括动态和连续的全球导航卫星系统和干涉合成孔径雷达。这将改善对多个时间和空间尺度上的构造应变场的约束。目录和区域震源数据将结合起来，然后将对整个区域的地震和大地测量观测进行Kostrov总和比较，以评估无地震形变的数量和空间变化，并限制岩石圈的性质。新的大地测量和地震结果将用于生成该地区变形运动学的改进模型，该模型与其他地质和地球物理数据一致，并可用于评估当前寒冷、强烈岩石圈的应变局部化模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Rifting, which leads to the breakup of continents and the formation of new ocean basins, is one of the fundamental processes in plate tectonics. East Africa is the prime example of present-day continental rifting. While a number of studies have yielded important insights in the older, more developed rifts in northern East Africa, there are major gaps in our knowledge of how rifting begins and develops due to sparse data in the younger Western and Southwestern rift systems. In particular, there is significant uncertainty about how far ground deformation related to early-stage rifting extends across the region and to what extent deformation may occur without earthquakes. This project will use a combination of ground deformation data from GNSS/GPS data, Synthetic Aperture Radar Interferometry (InSAR), and permanent seismometers to measure and investigate the kinematics of early-stage rifting across the Western and Southwestern rifts. Results will improve our understanding of fundamental tectonic processes and earthquake hazard estimates in the region. The project will provide student research opportunities at both the undergraduate and graduate levels, develop international research collaborations, and contribute to capacity building in science and technology through outreach in secondary schools in the USA and Africa and providing opportunities in training in data processing and analysis through in-country workshops and visits to US research institutions.The overall goal of this project is to test existing models of how rifting is distributed across uplifted and faulted areas of Central Africa surrounding the Western and Southwestern segments of the East African Rift and determine what component of the active rifting is aseismic. To achieve this goal, geodetic measurements, including campaign and continuous GNSS and InSAR, in this under-studied area will be increased. This will provide improved constraints on the tectonic strain field across multiple temporal and spatial scales. Catalogue and regional seismic source data will be combined and then Kostrov summation comparisons of seismic and geodetic observations across the region will be performed in order to evaluate the amount and spatial variation in aseismic deformation and to constrain lithospheric properties. The new geodetic and seismic results will be used to generate an improved model of the kinematics of deformation in the region that is consistent with other geological and geophysical data and can be used to evaluate current models of strain localization in cold, strong lithosphere.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.