Feature of cascading rupture frequently observed in Northern California

Understanding if earthquakes of different sizes start in the same way and whether the growth process of the rupture of large earthquakes is predictable are fundamental questions in earthquake physics. Recent studies indicate the onsets of seismic waves from small and large earthquakes exhibit similar characteristics, suggesting that an earthquake’s onset does not dictate its final size. However, the factors controlling this process remain unclear. A systematic comparison of 24 years of high-sensitivity seismograph records using cross-correlation for ~75,000 events reveals 125 extremely similar and 1939 similar pairs of co-located large and small earthquakes. An extremely high similarity is observed for pairs of earthquakes occurring on simple faults (44 of 55 large events), whereas large earthquakes occurring on complex faults have a low probability of cascading rupture. Estimating the probability of cascading rupture based primarily on fault geometry can improve the predictability of future earthquakes with a more quantitative size estimation. Pairs of co-located large and small earthquakes that share almost identical seismic wave onsets more frequently occur on simple fault than complex fault systems, according to an analysis of 24 years of seismic records from Northern California