Potency–Magnitude Scaling Relations and a Unified Earthquake Catalog for the Western United States

Abstract

Quantifying the size of earthquakes is a foundational task in seismology, and over the years several magnitude scales have been developed. Of these, only scales based on seismic moment or potency can properly characterize changes in event size without saturation. Here, we develop empirical potency–magnitude scaling relations for earthquakes in the western United States, allowing us to translate instrumental magnitude estimates into uniform measures of earthquake size. We use synthetic waveforms to validate the observed scaling relations and to provide additional insight into the differences between instrumental and physics-based magnitude scales. Each earthquake in our catalog is assigned a clustering designation distinguishing mainshocks from triggered seismicity, along with a potency-based magnitude estimate that is comparable to moment magnitude and that can be easily converted into other magnitude scales as needed. The developed catalog and associated scaling relations have broad applications for fundamental and applied studies of earthquake processes and hazards.