(CNN) — Authorities are assessing the damage after a strong earthquake shook Northern California on Sunday.
According to the U.S. Geological Survey, the 6.0 magnitude struck six miles southwest of Napa. It damaged several buildings, sparked fires and cut off power to thousands of people.
A Napa hospital reports treating nearly 90 patients for injuries. At least three people are reported to have critical injuries, including young girl struck by a falling fireplace.
Officials say the situation could have been much worse, and credit the quick action of first responders.
“We have relative calm in the community because of the – I think a lot of that had to deal with the overwhelming response that we had from our 9-1-1 staff, our police officers and our firefighters who live here in town, who came in without having to be called in,” said Steve Potter, the Operations Captain at the Napa Police Department.
At least five aftershocks followed the quake, according to the USGS. California Governor Jerry Brown has declared a state of emergency to free up additional resources for clean-up. It is the strongest earthquake to hit the Bay Area since 1989.