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

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).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.