Spatiotemporal Characteristics of Tectonic Tremors in California

Abstract California, as a transform plate boundary, provides a distinctive tectonic setting and an ideal natural laboratory for investigating tectonic tremors and the slow deformation associated with plate motion. By analyzing continuous seismic records across multiple stations with an envelope correlation method, we identified ∼83,000 tremor events from 2000 to 2025. These events exhibit waveform characteristics consistent with tectonic tremors observed elsewhere. Beyond the previously documented central section of the San Andreas fault, we identify several new tremor clusters, primarily concentrated near the Mendocino Triple Junction and within the Big Bend segment. Our results suggest that tremor events near the Mendocino Triple Junction may mark the southern edge of the Cascadia subduction zone, while tremor events in the Big Bend region, located within the rupture zone of the 1857 M7.9 Fort Tejon earthquake, could have implications for regional seismic hazard.