Dynamics, Patterns, and Migration in Earthquake Fault Systems

Space-time patterns of earthquakes have been described for many years. These include migration of major earthquakes along fault systems, precursory quiescence, precursory activation, aftershock diffusion, Mogi donuts, long range triggering as in the Landers earthquake, episodic tremor and slip, and precursory chains. A major goal is to use understanding of space time patterns to inform predictions and forecasts of future activity. Online catalogs of earthquakes combined with new analysis techniques based on statistical mechanics, and newly developed sophisticated numerical simulations of fault systems have led to new approaches for understanding these complex dynamical phenomena. In this talk, we summarize a number of these developments, and show how these new methods can be used to deliver information on earthquake occurrence over the web. Examples of these methods include the Virtual California simulation, and the Natural Time Weibull method for computing earthquake probabilities. In the former, we use information about fault system geometry, slip rates, and historic events to build a topologically realistic model of the fault system dynamics. Models of this type show evidence of many of the types of migration and chain behavior that natural earthquakes demonstrate. In the latter, the Natural Time Weibull model makes use of the fat tailed statistics observed for natural earthquakes to compute earthquake probabilities. Using this method for example, it can be seen that earthquake activity south of the island of Japan may have led to the triggering of the devastating M9.1, March 11, 2011 earthquake and tsunami. We describe prospects for active use of these models and methods of analysis in the future.