UCLA

This project’s objective is to map surface deformation over the Afar Depression since 1997 in real time to characterize fault behavior and contribute to the current repertoire of knowledge surrounding rifting processes. The Afar Depression is a broad extensional region in Eastern Africa, where the diverging boundaries have not yet achieved connection, so extension is distributed across developing arrays of faults and fractures. There has been generally limited attention from previous studies on the amount of divergence accommodated by distributed extension resulting from the transmission of tectonic forces applied to boundaries, in tangent with limited geodetic coverage and observations. To understand the mechanical processes underlying rift evolution, the current strain rate of the crust and its character over time throughout the Afar Depression must be understood in relation with the distribution of Quaternary faulting and rifting. To study the present-day deformation field, we use the technique of Synthetic Aperture Radar Interferometry (InSAR) — a method to measure ground deformation in map — with a dense archive of SAR data from two satellite missions: the Canadian Space Agency's (CSA) C-band RADARSAT-1 and the European Space Agency's (ESA) C-band Sentinel-1 missions. The mm/year resolution of InSAR time series measurements allows us to detect and monitor deformation throughout the Afar Depression in between events as large and fast as significant earthquakes and volcanic eruptions and also as small and slow as small dike intrusions over multiple decades. Using this data, we have modelled multiple discrete faulting events which were not captured before in the geodetic nor seismological record. Finally, to constrain the long-term extension rate and the distribution of extension across the Arabia-Somalian plate boundary, we compiled a detailed estimate of cumulative extension and vertical throw by measuring faults across the plate boundary using a high-resolution German Aerospace Center (DLR) TanDEM-X Digital Elevation Model (DEM).