Sylvain Michel, Geoazur

How large can an earthquake grow?  Effect of geometrical and  energetical barriers.

For large earthquakes to occur, seismic ruptures need to propagate  long distances along-strike and overcome different types of barriers. Understanding how far an earthquake can propagate includes assessing the effectiveness of these barriers in stopping earthquakes, which  depends on the characteristics of both the rupture and barriers. It  also includes the evaluation of a portion of a fault to be ready to host an earthquake as it will depend, among other factors, on the  energy accumulated since the occurrence of the previous large event. There is thus a time dependency.

In this talk, I will focus on both of these aspects. First, I will  discuss about geometrical barriers, due to geometrical complexities  along a fault (e.g. gaps and steps), within the framework of the  rate-and-state friction law. Next, I will discuss about energetical  barriers based on a recent extension of Linear Elastic Fracture  Mechanics theory to elongated ruptures. The work presented here adopts  a probabilistic approach and aims to integrate certain aspects of the physics of rupture propagation into seismic hazard analysis.