4.6 Magnitude Earthquake in Santa Cruz Mountains Shakes Bay Area Awake

Bay Area residents were jolted awake by a magnitude 4.6 earthquake early Thursday morning.

The U.S. Geological Survey reported the quake, which was centered about a mile from Boulder Creek in the Santa Cruz Mountains, around 1:40 a.m.

South Bay residents reported feeling the strongest tremors, with some saying they felt a sharp jolt followed by about 30 seconds of rolling and shaking. Across the Bay Area, the quake’s impacts were felt in San Francisco and Oakland, and as far north as Santa Rosa.

It was originally recorded as a magnitude of 5.1, but was downgraded to 4.6 by the USGS.

Early reports indicated little damage and no injuries as a result.

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%.