Humboldt Co. earthquake: Here's why Tsunami Warning was issued, then canceled

SAN FRANCISCO (KGO) -- A major 7.0 magnitude earthquake struck off the coast of Humboldt County near the town of Rio Dell on Thursday prompting officials to issue a Tsunami Warning for much of the Northern California coast including the San Francisco Bay Area.

However, just hours after issuing that warning, officials canceled it. But why?

LIVE UPDATES: 7.0 quake felt in Bay Area, Tsunami Warning canceled

Temblor CEO and Stanford Geophysics lecturer Ross Stein joined ABC7 News to detail what caused the U.S. National Tsunami Warning Center to initially issue that warning and why they ultimately decided to cancel it.

"It was a very weird, very shallow earthquake that involved a lot of vertical motion of the seafloor, which tends to produce more tsunamis, and that was the basis for that warning that we all received, but subsequently it turned out to be a larger earthquake, a magnitude 7, but a very typical garden variety event on this northern extension of the San Andreas Fault, which we call the Mendocino Fault Zone. In that respect it doesn't move this effore up and down very much, and it would be very unlikely for this earthquake to produce a large tsunami," said Stein.

As for the possibility of a large quake? Stein says that's always possible due to the location of this earthquake.

"There is a possibility that something larger can occur, and this region is really the hatchery of large earthquakes in California," said Stein. "It's the most active seismic area in the entire state, just off shore Mendocino, and that's because the San Andreas hangs the left, right at Cape Mendocino. There should be a blinking left turn signal there, and when it does so there's kind of a crunch that goes on in the crust that produces lots of earthquakes."

Watch the full interview in the media player above.