BREAKING: Earthquake hits coast of northern California, tsunami warning issued

An earthquake struck northern California on Thursday, with the epicenter lying just off the coast of Fortuna, according to the US Geological Survey. 

The earthquake was initially reported as being 6.6 in magnitude, but was upgraded to a 7.0. 

The US National Tsunami Warning Center has issued a tsunami warning spanning from Davenport, California to the Douglas County/Lane County line in Oregon. The warning affects at least 5.3 million California residents, ABC 7 reported. A warning message sent to phones read, "A series of powerful waves and strong currents may impact coasts near you. You are in danger. Get away from coastal waters. Move to high ground or inland now. Keep away from the coast until local officials say it is safe to return."

Included under the warning is the entire San Francisco Bay area. There are major delays with the BART transportation system and the Transbay Tube is closed to train service, which travels underwater. The San Francisco Zoo wrote, "The Zoo has closed due to national weather emergency and tsunami warning. Guests have been evacuated, animals secured and staff have moved to higher ground."

Several aftershocks have hit, including a 5.8-magnitude one near Cobb, California, and others registering between 2.5 to 4.2 in magnitude, per CBS News.

"Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring.  Tsunamis are a series of waves dangerous many hours after initial arrival time. The first wave may not be the largest," the National Weather Service stated. Just before noon Pacific time, the US National Tsunami Warning Center canceled the tsunami warning. 

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