Project Abstract
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Faults undergo stick-slip cycles that lock, accumulate stress and release that stress in an earthquake. However, in most earthquakes only part of the fault slips and in between the earthquakes only part of the fault is locked. When and where the locking happens is a critical part of the earthquake cycle that is difficult to observe in nature. In particular, we would like to know how the strength, location and timing of the locking is related to the strength, location and timing of the eventual earthquakes. We use a fault made of transparent rubber that captures many of the important behaviors of faults in nature including having confined events that do not start or end at the system’s edge. Thus, the stresses on the fault are not reset with every slip event, but instead reflect the complex slip history. We directly image the entire movement history for more than 18000 distinct events. We see that there is a characteristic locking phase where the velocity on the slip patch increases in the direction of loading over a fixed locking distance, and that this locking is predictive of the size, timing, and location of the ensuing slip events. In this work, we will investigate the controls on the locking distance. This advance will allow generalization of the results and inform future theoretical models. This work will help achieve SCEC milestone D2-2. |
