EARTHSCOPE IN 4D: VISUALIZING EARTHQUAKE CYCLE STRESS EVOLUTION AT DEPTH ALONG THE SAN ANDREAS FAULT SYSTEM (Invited Presentation)

EarthScope geodetic and seismic observations, combined with sophisticated computational models and powerful visualization tools, are now providing a critical ensemble of information about stressing rates along the San Andreas Fault System (SAFS). When combined with paleoseismic chronologies of earthquake ruptures spanning the last several hundreds of years, four-dimensional (4D) simulations of stress evolution spanning multiple earthquake cycles are now possible. To investigate stress variations at depth along the SAFS over multiple earthquake cycles, we use a 4D semi-analytic model that simulates interseismic strain accumulation, coseismic displacement, and post-seismic viscoelastic relaxation of the mantle. The model utilizes geologic estimates of fault locations and geologic slip rates, as well as paleoseismic earthquake rupture histories spanning the last 1000 years. Using EarthScope Plate Boundary Observatory data, we tune the model locking depths to compute the 4D stress accumulation within the seismogenic crust. We use ParaView 3.10, an open-source multi-platform visualization package, for manipulation and visualization of 4D stress variations spanning a ~1000 x 1500 x 50 km volume of the SAFS. We present a snapshot of earthquake cycle stress behavior of the SAFS spanning the past 250 years, illustrating how stress accumulation and stress drop are a complex function of space and time. These visualizations lay the groundwork for the next generation of earthquake cycle models that will focus on the implications of stress concentrations at depth due to the interaction of neighboring fault segments and branching junctions.