Japan, Toyama: 1967-2024

The Toyama cluster is named for Toyama Prefecture on the northwest coast of Honshu, Japan. It is based on a 7.5 Mw earthquake on January 1, 2024. The cluster includes a foreshock and 32 aftershocks of the first 36 hours. The area has been seismically active for many years and the cluster includes many earlier earthquakes that provide the data coverage necessary for location calibration. Fluid flow driven by magmatic activity has been identified as a likely cause of seismicity in the area by Keisuke Yoshida and colleagues. Nearly all events in the cluster are observed to teleseismic distances. Most events have depth control from near-source and local-distance arrivals, but a few are set to the default depth of 15.0 km with 7.2 km uncertainty [...]