Decadal Seismicity before Great Earthquakes—Strike-Slip Faults and Plate Interiors: Major Asperities and Low-Coupling Zones

Decadal forerunning seismic activity is examined for very large, shallow earthquakes along strike-slip and intraplate faults of the world. It includes forerunning shocks of magnitude Mw ≥ 5.0 21 mainshocks 7.5 to 8.6 from 1989 2020. Much occurred at what are interpreted be smaller asperities along peripheries rupture zones great at transform subduction zones. Several asperities as ascertained from agree with areas high seismic slip determined by others using geodetic, mapping surface faulting, finite-source modeling. The zones in many were nearly quiescent beforehand and identified sites asperities. Asperities strong, well-coupled portions plate interfaces. Different patterns forerunning activity on time scales up 45 years attributed sizes and spacing (or lack of). This permits least some asperities along transform mapped decades before they great shocks. Rupture are bordered either strike, depth or regionally lower plate coupling including fault creep  forerunning activity, aftershocks and/or slow-slip events. Forerunning transforms in continental more widespread spatially than that adjacent oceanic transforms. The parts San Andreas themselves ruptured in great California during 1812, 1857 1906 have been quiet since 1920; moderate large shocks concentrated their peripheries. studied, however, exhibited few if any forerunning events, which short period studied compared their repeat times. detection precursory activities various should sought great asperities not just major themselves. paper compliments decadal giant earthquakes along