Prithvi Thakur , Yihe Huang

We study the mechanical response of two-dimensional vertical strike-slip fault to coseismic damage evolution and interseismic healing of fault damage zones by simulating fully dynamic earthquake cycles. Our models show that fault damage zone structure evolution during the seismic cycle can have pronounced effects on the mechanical behavior of locked and creeping fault segments. Immature fault damage zones promote small and moderate subsurface earthquakes with irregular recurrence intervals and abundance of slow-slip events during the interseismic period. In contrast, mature fault damage zones host pulse-like earthquake ruptures that can propagate to the surface and extend throughout the seismogenic zone, resulting in large stress drop, characteristic rupture extents, and regular recurrence intervals. Our results suggest that interseismic healing and coseismic damage accumulation in fault zones can explain the observed differences of earthquake behaviors between mature and immature fault zones and indicate a link between regional seismic hazard and fault structural maturity.