Supershear earthquakes: what has and what could happen?

Resume: Supershear, or intersonic, earthquakes are those earthquakes where the rupture velocity is higher than the shear wave velocity of the rocks through which they break. Theory has long predicted that earthquake ruptures at this speed are possible, although debate remained as to how earthquake ruptures could accelerate through the shear wave velocity and reach supershear speeds. Potentially the damage pattern associated with a supershear earthquake is very different to a classical sub-shear event, a fact which is not taken into account in current building codes. Within the last 10 years, interest in the subject has intensified, firstly as a result of laboratory experiments showing the sub-supershear transition and then by the occurrence of two large earthquakes in 2001 (Kunlun) and 2002 (Denali) that seem to have ruptured for long distances at supershear velocities. This talk will review the evidence for supershear ruptures, hypothesise on some of the necessary conditions for supershear rupture to occur and apply these conditions to faults around the world to identify those areas where further work should be undertaken to accurately determine the seismic hazard. -------------------------------------------------------------------------------- Séminaires généraux de l'Institut de Physique du Globe de Paris --------------------------------------------------------------------------------