Fault Interactions Enhance High‐Frequency Earthquake Radiation

Abstract

Abstract Fault complexity has been linked to high‐frequency earthquake radiation, although the underlying physical mechanisms are not well understood. Fault complexity is commonly modeled with rough single faults; however, real‐world faults are additionally complex, existing within networks of other faults. In this study, we introduce two new ways of defining fault complexity using mapped fault traces, characterizing fault networks in terms of their degree of alignment and density. We find that both misalignment and density correlate with enhanced high‐frequency seismic radiation across Southern California, with misalignment showing a stronger correlation. This robust correlation suggests that high‐frequency radiation may arise in part from fault‐fault interactions within networks of misaligned faults. Fault‐fault interactions may therefore have important consequences for earthquake rupture dynamics, energetics and earthquake hazards and should not be overlooked.