Numerical modelling and geodetic observations improving our understanding about seismic barriers

by Diego Molina (ISTerre, Grenoble, France)

Understanding what controls the maximum size of an earthquake is essential to estimate seismic hazard. Typically, zones promoting seismic rupture arrest along subduction megathrusts have been correlated with the subduction of bathymetric anomalies. They are often characterised by intermediate-low coupling, however the mechanisms producing such feature are poorly understood. To better understand potential frictional regime governing barrier behaviour, we perform numerical modelling simulations of the seismic cycle. We also recur to geodetic data to constrain how seismic barrier behaves in nature. Our results suggest that seismic barriers can display both Velocity weakening or Velocity strengthening regime. Posible mechanisms controlling the different frictional behaviour might be associated to subducting topography which provoke fault heterogeneities.
Finally, our study supports that geological characteristics of subducting and overriding plates can impact fault behaviour.

Mis à jour le 24 octobre 2024