Earthquake source parameters from GPS-measured static displacements with potential for real-time application

We describe a method for determining an optimal centroid-moment tensor solution of an earthquake from a set of static displacements measured using a network of Global Positioning System receivers. Using static displacements observed after the 4 April 2010, M-W 7.2 El Mayor-Cucapah, Mexico, earthquake, we perform an iterative inversion to obtain the source mechanism and location, which minimize the least-squares difference between data and synthetics. The efficiency of our algorithm for forward modeling static displacements in a layered elastic medium allows the inversion to be performed in real-time on a single processor without the need for precomputed libraries of excitation kernels; we present simulated real-time results for the El Mayor-Cucapah earthquake. The only a priori information that our inversion scheme needs is a crustal model and approximate source location, so the method proposed here may represent an improvement on existing early warning approaches that rely on foreknowledge of fault locations and geometries. Citation: O'Toole, T. B., A. P. Valentine, and J. H. Woodhouse (2013), Earthquake source parameters from GPS-measured static displacements with potential for real-time application, Geophys. Res. Lett., 40, 60-65, doi: 10.1029/2012GL054209.