Monitoring Aseismic Forcing in Fault Zones Using Earthquake Time Series

The dynamics of earthquake occurrences is controlled both by fault in- teraction processes and by long-term, tectonic loading of the faults. In addition, tran- sient loading can be caused by aseismic deformation episodes, for example during crustal fluid migration or slow slip events. These forcing transients are best revealed by geodetic measurements. However, this type of instrumentation is not always avail- able, or is not always sensitive enough to detect significant anomalies. In such cases, one is better off exploiting the seismicity signature of these transients in order to char- acterize them. We here explore different ways to do so. Interearthquake time statistics are found to be prone to damping out fluctuations in forcing rate. A more accurate method is developed by comparing the data with a triggering model that accounts for earthquake interactions. The changes in fault loading rates are then well recovered, both in duration and in intensity.