Lighting darkens fault scarps.
Recent earthquakes have shown that fault interaction can affect rupture sequences. However, few criteria are currently available to determine which fault segments are strongly interacting. Here we develop a simple, elastic-plastic model of fault interaction that can assess degrees of interaction within a population of faults using only map traces or displacement profiles. In this model, faults interact through their stress fields. There is a positive linear relationship between the amount of stress reduction felt at a tip and anomalous displacement accumulation near this tip.