Stress interaction, rate-state friction, and earthquake triggering

Over the past 10 years it has become very clear that stress changes due to large earthquakes can increase the likelihood of future large earthquakes. For example, the 26 December 2004 earthquake near Sumatra triggered the 28 March 2005 event near Nias Island and the increase in seismic risk in this area was noted in a paper published 11 days before the earthquake. Although such stress changes can be used to delineate areas of greater risk, it is very questionable as to whether we can say anything meaningful about the probability of earthquake occurrence in such regions. The problem is that the one model that relates stress and probability changes relies on a number of assumptions that may not be justified in reality. Testing the model with real earthquakes is difficult due to the small number of large events and issues with data quality in poorly instrumented areas. Hence, we propose to use a sophisticated seismic simulation model to systematically test whether earthquake probability changes can be related to stress changes.