Delayed triggering of the 1999 Hector Mine earthquake by viscoelastic stress transfer

摘要: Stress changes in the crust due to an earthquake can hasten failure of neighbouring faults and induce sequences some cases1,2,3,4,5. The 1999 Hector Mine southern California (magnitude 7.1) occurred only 20 km from, 7 years after, 1992 Landers (magnitude 7.3). This suggests that was triggered fashion by earlier event. But uncertainties slip distribution rock friction properties associated with have led widely varying estimates both magnitude sign resulting stress change would be induced at location hypocentre—with from -1.4 bar (ref. 6) +0.5 bar 7). More importantly, coseismic alone cannot satisfactorily explain delay between two events. Here we present results a three-dimensional viscoelastic model simulates transfer ductile lower upper mantle brittle following earthquake. Using parameters reproduce observed horizontal surface deformation earthquake, our calculations suggest lower-crustal or upper-mantle flow lead postseismic increases up 1–2 bar hypocentre during this time period, contributing eventual occurrence These attest importance considering processes assessment seismic hazard8,9,10,11.