Forecasting the evolution of seismicity in southern California: Animations built on earthquake stress transfer

We develop a forecast model to reproduce the distribution of main shocks, aftershocks and surrounding seismicity observed during 1986–2003 in a 300 × 310 km area centered on the 1992 M = 7.3 Landers earthquake. To parse the catalog into frames with equal numbers of aftershocks, we animate seismicity in log time increments that lengthen after each main shock; this reveals aftershock zone migration, expansion, and densification. We implement a rate/state algorithm that incorporates the static stress transferred by each M ≥ 6 shock and then evolves. Coulomb stress changes amplify the background seismicity, so small stress changes produce large changes in seismicity rate in areas of high background seismicity.…