5.1 quake hit Northern California before 6 a.m. followed by 4.5 less than a half hour later

A magnitude-4.8 quake struck the North Coast about 15 minutes before 6 a.m., according to USGS on Wednesday morning. A ShakeAlert message was received in the Eureka area before 6 a.m. noting that “if shaking intesifies: Drop, cover and hold on.”

Later, the quake was upgraded to a magnitude-5.1.

The 5.1 earthquake was 40 miles off the coast of Petrolia, according to information posted by USGS on Wednesday morning.

Early Did You Feel It responses on the USGS website were from Arcata and Ferndale. Later, the felt reports ranged from Westport in Mendocino County to Blue Lake.

Additionally, there was a 4.5 shaker at 6:11 a.m. off the coast of Ferndale, the USGS reported, and a 3.8 around 8:50 a.m.

It was a busy morning for North Coast earthquakes, according to a post by the Redwood Coast Tsunami Work Group on Facebook. Folks in Del Norte received an earthquake notification before 4 a.m.

“Some of you may have gotten ShakeAlert messages early this morning,” the post stated. ” A few people on the Del Norte and Curry County coast were notified of a M 5.7 offshore of the CA-OR border at 3:53 AM PDT centered 104 miles WNW of Crescent City. It was reported felt by a few from Scotia to Reedsport. ShakeAlerts were also issued after a M5.2 earthquake occurred on the Mendocino fault at 5:53 AM PDT 40 miles W of Petrolia. That earthquake was felt lightly from Westport to Brookings and was followed by a M4.5 26 minutes later that was also felt lightly by some in Humboldt County.”

The three quakes are not necessarily related, the post notes.

“These earthquakes were not directly related, the first was in the Gorda plate near an area where a number of earthquake in the M5 range have occurred in the past year and the second was on the Mendocino fault and arguably an aftershock of the December 5, 2024 M7,” the post stated.