A significant earthquake rocked the San Francisco Bay area early Sunday morning.

According to the United States Geological Survey, the 6.0 magnitude earthquake struck 51 miles southwest of Sacramento — close to Napa Valley. The earthquake hit about 6.7 miles deep, which constitutes as a shallow earthquake. According to the USGS, it's the largest earthquake in the area since the Loma Prieta quake in 1989, a 6.9 magnitude quake.

Here's the map of the earthquake's epicenter:

USGS

California Gov. Jerry Brown (D) declared a state of emergency later Sunday morning after the quake and its aftershocks " damaged critical infrastructure, homes and other structures and caused fires and the closure of roads and highways."

Users on Twitter reported power outages in Napa, Sonoma, and other spots throughout the area. The California Highway Patrol in Santa Rosa said there were widespread power outages in the area, including multiple power poles down. The CHP said there was no visible damage on overpasses and bridges in the area.

so scary power out it Sonoma - anyone else?

— Elyssa Toda (@Elyssa) August 24, 2014

Earthquake. Power out, shattered glass everywhere.

— Daniel Wiesenthal (@DanWiesenthal) August 24, 2014

Power out here in Napa. Stuff fell of shelf here. Very big initial jolt. Disorienting.

— Jacob Soboroff (@jacobsoboroff) August 24, 2014

The Los Angeles Times' Ryan Parker tweeted a map in the immediate aftermath of the quake showing the massive extent of power outages in the Bay area:

This map for PG&E shows massive outages in the bay area after the #earthquake pic.twitter.com/GZodsPK2n5

— Ryan Parker (@TheRyanParker) August 24, 2014

There were no immediate reports of critical injuries stemming from the earthquake. Napa police said on Twitter that they were actively working the area for earthquake-related issues. In a statement early Sunday morning, Brown urged residents to stay calm.

"My Office of Emergency Services has been on full activation since early this morning and is working closely with state and local emergency managers, first responders and transportation officials to respond to impacts to residents and critical infrastructure," Brown said.

"These public safety officials are doing all they can to help residents and those living in affected areas should follow their guidance and instruction."

Here are some photos from the Twittersphere:

In napa. biggest ever pic.twitter.com/yLYMnC9Q54

— Tim Gatto (@Tim_Gatto) August 24, 2014

What that looked/felt like for in laws in Napa. #earthquake pic.twitter.com/avTYVedRkn

— Andrew Crookston (@acr) August 24, 2014