Numerical Insight Into Energy Partitioning During Stick-Slip Events Based on the Framework of Rate-and-State Friction Law

Abstract

Many attempts have been made to investigate the energy budgets of stick-slip events, however, the strain energy contribution is still poorly understood. We developed a discrete element method (DEM)-based method to mimic stick-slip events and the associated energy partitioning. We found that stress drop Δσ, breakdown energy EG, and strain energy release ΔU scale with slip δc as (Formula presented.), (Formula presented.), and (Formula presented.), respectively, which is quantitatively consistent with data from manmade seismicity and natural earthquakes. We observed two different slip-weakening behavior patterns: one without a postseismic phase (Type I) and one containing a postseismic phase (Type II). We show that ΔU contributes 20%∼90% (63% on average) and 10% ∼ 60% (38% on average) to the total energy budget for Type I and Type II events, respectively. Formations that store higher strain energy play a more vital role in the earthquake energy budget, regardless of the distance to the fault.