Small communities that bore the brunt of a strong earthquake on the coast of far Northern California remained without power and under boil-water advisories Wednesday.

Most of the 72,000 Humboldt County customers who lost electricity when the quake struck before dawn Tuesday had power restored by evening, but Pacific Gas & Electric’s website showed about 14,000 still without electricity more than 24 hours later.

Most of the remaining outages were in the communities of Fortuna, Ferndale and Rio Dell. Boil water advisories were issued for Rio Dell and parts of Fortuna because of damaged water systems.

The magnitude 6.4 earthquake occurred at 2:34 a.m. Tuesday near Ferndale, about 210 miles (345 kilometers) northwest of San Francisco and close to the Pacific coast. The epicenter was just offshore at a depth of about 10 miles (16 kilometers). Aftershocks followed.

The quake jolted people awake and shook homes off foundations, injuring at least 12.

Residents in the area known for its redwood forests, scenic mountains and the three county Emerald Triangle’s legendary marijuana crop are accustomed to earthquakes. But many said this was more violent and unnerving than the usual rolling motion they experience.

“You could see the floor and walls shaking,” said Araceli Huerta. “It sounded like a freight train was going through my house.”

Two Humboldt County hospitals lost power and were running on generators, but the scale of the damage appeared to be minimal, considering the strength of the quake, according to Brian Ferguson, a spokesperson for the California Governor’s Office of Emergency Services.

Gov. Gavin Newsom proclaimed a state of emergency for Humboldt County on Tuesday evening.

About 12 people were reported as suffering injuries, including a broken hip and head wound, the Humboldt County Sheriff’s Office said at a news conference interrupted by an aftershock. Two people died — an 83-year-old and a 72-year-old — because they couldn’t get timely care for “medical emergencies” during or just after the quake.

Damage was mostly focused on Rio Dell, Ferndale and Fortuna, Emergency Services Director Mark Ghilarducci said during a news conference in Sacramento.

In Rio Dell, a hamlet of about 3,000 people where destruction was worst, at least 15 homes were severely damaged and deemed uninhabitable and 18 others were moderately damaged, officials said after a partial assessment. They estimated that 30 people were displaced and said that number could rise to 150.

The city’s water system was shut down for repairs because of leaks. Portable toilets were set up at City Hall and water was being handed out at the firehouse.

A bridge over the Eel River built in 1911 that is the main route into Ferndale was damaged and closed to traffic, requiring a longer detour through the mountains to reach the quaint Victorian town, where all of Main Street is on the National Register of Historic Places.

Since a magnitude 7.2 quake in the area in 1992 injured hundreds, sparked fires and destroyed many homes, building codes have required retrofits to make structures much more resilient to the shaking, said Caroline Titus, former owner of the Ferndale Enterprise newspaper.

Humboldt County has about 136,000 residents and is in a part of the state that has a long history of large earthquakes.

The earthquake occurred in an area known as the Mendocino Triple Junction, where three tectonic plates meet.

The quake triggered a massive response by the West Coast’s warning system that detects the start of a quake and sends alerts to cellphones in the affected region that can give people notice to take safety precautions in the seconds before strong shaking reaches them.

The system pushed out alerts to some 3 million people in Northern California early Tuesday, officials said.

(AP)