Resolving Differences in the Rupture Properties of M5 Earthquakes in California Using Bayesian Source Spectral Analysis

The spectra of earthquake waveforms can provide important insight into rupture processes, but the analysis and interpretation these is rarely straightforward. Here we develop a Bayesian framework that embraces inherent data modeling uncertainties spectral to infer key source properties. method uses ratio approach correct observed S-wave nearby earthquakes for path site attenuation. objective then solve joint posterior probability distribution three parameters—seismic moment, corner frequency, high-frequency falloff rate—for each in sequence, as well measure directivity select target events with good azimuthal station coverage. While computationally intensive, this technique provides quantitative understanding parameter tradeoffs allows one impose physical constraints through prior distributions on all parameters, which guide inversion when limited. We demonstrate by analyzing detail properties 14 different magnitude M5 southern California span wide range tectonic regimes fault systems. These prominent earthquakes, while comparable size, exhibit marked diversity their directivity, clear spatial patterns, depth-dependent trends, preference unilateral directivity. coherent variations suggest regional differences setting, hypocentral depth or zone characteristics may drive variability implications our physics its relation hazard.