PETROLIA, California. – A series of powerful earthquakes struck Humboldt County in Northern California on Thursday morning, causing chaos, particularly in coastal communities from the Golden State to Oregon.

The initial brightness was measured at 6.6, according to the USGS.

The earthquake has now been upgraded to a magnitude of 7.0. A second earthquake occurred near Ferndale with a magnitude of 5.8.

The first earthquake struck around 10:45 a.m. in the town of Petrolia, about 50 miles from Eureka.

The National Weather Service immediately issued a tsunami warning along the coast of California and Oregon from the Santa Cruz area to Douglas County, Oregon.

As of 11 a.m., Humboldt and Mendocino County officials had not received any reports of damage

Closer to home, Bay Area residents in Dublin, Santa Cruz, Belmont, Cotati, Castro Valley, San Francisco, Napa and Sunnyvale reported feeling the quake.

Tina Killinger works as a medical assistant at Kaiser in Rohnert Park.

When the quake struck, everyone received an alert on their cell phones and headed to the doorways.

She said she saw the lights above them wavering.

“It seemed to take a while,” she said.

But no one was hurt and everyone went back to work.

Efforts to reach local officials in cities like Eureka and Fortuna were not immediately successful.