Repeating Earthquakes as Low-Stress-Drop Events at a Border between Locked and Creeping Fault Patches

摘要: The source of repeating earthquakes on creeping faults is modeled as a weak asperity at border between much larger locked and patches the fault plane. x –1/2 decrease in stress concentration with distance from boundary shown to lead directly observed scaling 〈 T 〉∞〈 M 〉1/6 average repeat time scalar moment for sequence. drop such small events depends size large patch. For circular patch radius R representative parameters, Δσ = 7.6( m / )3/5 MPa, which yields drops 0.08 0.5 MPa (0.8–5 bars) 2 km 100 m. These low are consistent estimates based their seismic spectra. However, they orders magnitude smaller than calculated under assumption that sources isolated stuck asperities an otherwise plane, whose slips keep pace surrounding creep rate. Linear streaks microearthquakes planes trivially explained by present model alignments boundaries patches.