Martijn van den Ende , André Niemeijer

Owing to their destructive potential, earthquakes receive considerable attention from laboratory studies. In friction experiments, stick-slips are studied as the laboratory equivalent of natural earthquakes, and numerous attempts have been made to simulate stick-slips numerically using the Discrete Element Method (DEM). However, while laboratory stick-slips commonly exhibit regular stress drops and recurrence times, stick-slips generated in DEM simulations are highly irregular. This discrepancy highlights a gap in our understanding of stick-slip mechanics, which propagates into our understanding of earthquakes. In this work, we show that regular stick-slips emerge in DEM when time-dependent compaction by pressure solution is considered. We further show that the stress drop and recurrence time of stick-slips is directly controlled by the kinetics of pressure solution. Since compaction is known to operate in faults, this mechanism for frictional instabilities directly relates to natural seismicity.