It’s not clear what fault the quake occurred on. The San Andreas Fault, which caused the 1989 Loma Prieta earthquake, and the Hayward Fault, which has spurred multiple smaller seismic events over the last year, both run through the area.
As of 8 a.m., no significant aftershocks have been reported. While any earthquake can be a foreshock of a larger one to come, the likelihood is generally quite low.
According to USGS, there’s about a 25% chance of a magnitude 3.0 or greater quake in the next week, but the likelihood of a stronger 4.0 magnitude quake in that time drops to just 3%.
