Over 56,000 moderate to large earthquakes have occurred around the world since 1976, and a global earthquake catalog contains data on the fault geometry and kinematics of each of those earthquakes. A Global Block Model, constrained by GPS measurements, divides the Earth into fault blocks with kinematic data showing the movements of the blocks. Because earthquakes relieve the elastic strain that accumulates at fault boundaries, earthquake slip directions typically correspond to the direction of crustal movement at a particular fault. The goal of this project is to compare the global earthquake data to the block model in order to determine what percentage of earthquakes match the direction of fault slip predicted by the model. These comparisons can be made efficiently in MATLAB by matching the fault on which each earthquake occurred to nearby fault segments with the same geometry and kinematics. Although it is expected that the vast majority of earthquake slip directions will align with the modeled fault slip directions, some smaller earthquakes may be anomalous due to local stresses in the Earth, and even large subduction zone earthquakes may not match the model if strain is partitioned onto multiple faults. Discrepancies between the model and the earthquake catalog could be used to refine the Global Block Model.
A poster deriving from Special studies with Jack Loveless, Associate Professor of Geosciences.