The power-law spatial decay of aftershock density, modified from Mignan (2018) – Spatial linear density distribution of aftershocks for the four largest strike-slip mainshocks in southern California. Only the first generation of aftershocks is considered. Including secondary aftershocks (such as the events triggered by the Big Bear aftershock) adds some spatial heterogeneity on top of the main power-law decay (see dotted curve). The curves roughly follow, at first order, the dashed lines, indicative of a power-law behavior on a log-log plot. Here the power-law behavior starts at a distance greater than one kilometer away from the mainshock trace. Black contours are 10 km from the mainshock rupture on the map for scale.