Thousands of customers are still without power following a large earthquake in Northern California.

A magnitude 6.4 earthquake struck northern California on Tuesday, according to the U.S. Geological Survey.

Very strong shaking was reported from the quake, which struck in Ferndale roughly 200 miles north of San Francisco in the vicinity of the Mendocino triple junction where the Pacific, North America and Juan de Fuca plates meet, according to the USGS.

Pacific Gas & Electric power lines sparked last summer’s Dixie Fire in Northern California that swept through five counties and burned more than 1,300 homes and other buildings, state fire officials said Tuesday.

The blaze was caused by a tree hitting electrical distribution lines west of a dam in the Sierra Nevada, where the blaze began on July 13, according to investigators with the California Department of Forestry and Fire Protection.

Pacific Gas & Electric reported to California utility regulators that its equipment may have been involved in the start of a fire burning in the Sierra Nevada that is threatening hundreds of homes.

PG&E said in a report Sunday to the California Public Utilities Commission that a repairman responding to a circuit outage on July 13 spotted blown fuses in a conductor atop a pole, a tree leaning into the conductor and fire at the base of the tree.

The utility said its system showed around 7 a.m. that the Cresta Dam off Highway 70 had lost power but because of the steep, rough terrain, the worker sent to check it couldn’t reach the area until nearly 5 p.m.

A federal judge is weighing whether Pacific Gas & Electric violated its criminal probation by sparking a wildfire north of San Francisco that destroyed more than 100 homes and injured six firefighters in October 2019.

Prosecutors and attorneys for PG&E appeared at a hearing Tuesday before U.S. District Judge William Alsup, a month after the Sonoma County district attorney charged the company with five felony and 28 misdemeanor counts for a fire that destroyed 374 buildings and launched the largest evacuation in the county’s history, with nearly 100,000 people forced to flee.

A federal judge overseeing Pacific Gas & Electric’s criminal probation said Tuesday that he is considering requiring the utility to be more aggressive about turning off its electricity lines near tall trees, a plan that could double the number of power outages for some Northern California counties over the next decade.

The proposal outlined during a two-hour court hearing is the latest effort to prevent the utility’s equipment from sparking more deadly wildfires by reducing the likelihood that trees could fall into the utility’s long-neglected electrical equipment. U.S. District Judge William Alsup is overseeing PG&E’s safety precautions as part of the utility’s criminal probation after its natural gas lines blew up a suburban neighborhood south of San Francisco in 2010.