CAREER: Active forearc uplift, topographic growth, and permanent deformation above highly coupled subduction interfaces

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

This program will provide key information about the physical properties and conditions that may control the size of earthquakes in subduction zones, regions which are known to host the largest earthquakes globally. This research will be integrated with a series of activities specifically designed to increase the number of successful geoscience and STEM students that identify as an underrepresented minority. This project will support undergraduate research internships for underrepresented minority students at the University of California, Santa Barbara and Santa Barbara City College, and will host workshops and local field trips specifically designed to increase geoscience awareness and broaden student participation in outdoor experiences. The project will also support the training and professional development of two PhD geoscience students, who will also act as mentors to the undergraduate students. Long-term forearc uplift and topographic growth above locked seismogenic zones can segment the megathrust along-strike, which is predicted to restrict the maximum size of large subduction zone earthquakes. However, the conditions and mechanisms that ultimately produce permanent vertical tectonism in these settings remain poorly constrained globally. The program will use a combination of field observations, numerical dating, low-temperature thermochronology and landscape evolution modeling to test between three primary mechanisms of rock uplift and topographic growth in the highly-coupled subduction zone regions of Nicoya Peninsula, Costa Rica, and Kodiak, Alaska, USA. Constraining these conceptual models will have important implications for processes that result in seismic segmentation, such as the physical and rheological conditions between the decollement, lower plate, and overriding plate, and how strain is partitioned between the megathrust and the upper plate. 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.