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.

Federal officials have initiated a criminal investigation into PG&E Corp.’s potential role in starting California’s largest wildfire of the year.

On Sept. 24, the US Forest Service removed one of the utility’s transmission poles from the site in Placer County where the Mosquito fire started, PG&E said Monday in a filing. USFS didn’t immediately respond to inquiries about the probe.

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.

California power company Pacific Gas and Electric said on Wednesday it would bury 10,000 miles of power lines in high-risk fire zones as a safety measure after its equipment caused multiple destructive wildfires over several years.

The utility, which called the project a multi-year initiative, maintains more than 25,000 miles of overhead distribution power lines in the highest fire-risk zones, or more than 30% of its total distribution overhead system, according to the company.

The move by PG&E comes days after it said its equipment may have been involved in the start of a recent wildfire in Sierra Nevada, according to a filing by PG&E to regulators published on the internet by a San Francisco Chronicle journalist.

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.

The nation’s largest utility has long vowed to change its reckless ways, but year after year there’s more death and destruction from Northern California wildfires sparked by Pacific Gas & Electric’s equipment.

CEO Patricia “Patti” Poppe, who took over in January as the company’s fifth leader in less than three years, has pledged to shareholders that the future will get “easier” and “brighter.” That vow will be put to the test as California sinks deeper into drought and fire danger increases.

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.

California officials on Thursday voted to toughen oversight of Pacific Gas & Electric, saying the utility had largely failed to perform required tree-trimming work near power lines in areas with the highest risk of wildfires.

The unanimous vote by the California Public Utilities Commission comes as the fire-prone state has stepped up scrutiny of utility efforts to mitigate wildfire risk. Climate change is fueling increasingly frequent and intense blazes in the state that are often ignited by power infrastructure.

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.

Large swaths of California had no electricity Monday as utilities tried to prevent the chance of their equipment sparking wildfires while the fire-weary state was buffeted by powerful winds and dangerously dry weather conditions.

About 300,000 power customers, more than 1 million people, were in the dark as officials issued warnings for what could be the strongest winds for California this year.

North of San Francisco, a Mount St. Helena weather station recorded a hurricane-force gust of 89 mph late Sunday and sustained winds of 76 mph.