Big Impacts of Small Tremors. The Community Fault Model (CFM) of the Southern California Earthquake Center*: a study of Southern California earthquake history suggests that smaller quakes collectively trigger more aftershocks than do larger ones. Maps of the fault structure there (stripes) may need to account for even the smallest quakes in order to be accurate. (Dots are earthquake centers.) Image Credit: A. Plesch & J. Shaw/ Harvard Univ. for SCEC
Puny tremors may be the real movers and shakers of the seismic world. Recently published research by a geophysicist suggests that small earthquakes collectively trigger more aftershocks than do less frequent, larger temblors, according to earthquake records. She also proposes a new connection between the arrangement of earthquakes around a fault and the number of aftershocks. The findings could change how geoscientists model fault system stresses and estimate earthquake risk.