USGS: 11% chance of a magnitude 5 earthquake or larger in next week after 6.4 Humboldt Co. quake

ByLena Howland KGO logo
Tuesday, December 20, 2022
USGS: 11% chance NorCal quake followed by another 5 or larger
A USGS physicist explains the Humboldt County 6.4 magnitude earthquake and our chances of seeing more in the next week.

SAN FRANCISCO (KGO) -- Tuesday morning, while most people were still sleeping, things started crashing down from shelves in homes, cabinets and drawers pushed open, the Fernbridge cracking, leaving more than 70% of people (around 72,000 people) across Humboldt County in the dark, without any power.

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To the west of Ferndale, California, a 6.4 magnitude earthquake hit around 2:30 a.m.

While we don't know the full scope of the damage yet, scientists at the United States Geological Survey say there was nothing particularly unusual about this quake, as this is the sort of thing they expect to see in this area where multiple faults are all coming together at the same time.

"And because of that, it's a very seismically-active region, and there was a lot going on because all of these major plates are going in different directions which in turn is making a lot of secondary faults that are accommodating all sorts of motion to help the plates change direction," Sarah Minson, a research physicist for USGS said.

VIDEO: Humboldt Co. sheriff gives update on 6.4 earthquake, at least dozen injured

Humboldt County Sheriff William Honsal gives update on 6.4 earthquake, he says at least dozen people are injured.

Even causing multiple aftershocks right after the first earthquake.

According to the USGS forecast, there's a 50% chance of a magnitude 4 or larger earthquake happening and an 11% chance of a magnitude 5 or larger in the next week.

"Earthquakes always follow this pattern of every particular magnitude of an earthquake, there are 10 times as many of the next magnitude or smaller and 100 times as many the next magnitude or smaller," Minson said. "What happens is that the rate of earthquakes goes up and down, so when you have a significant earthquake, it kicks up the earthquake rate."

But they want to remind everyone to protect what's important to them in the event of an earthquake and know what to do if you feel any shaking.

"So the important thing to remember is to protect yourself. If you feel shaking, you should drop, cover and hold on until the shaking passes," she said.

The USGS added that there is only a 1% chance of a magnitude 6 or greater earthquake from happening in the next week.

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If you haven't put together an earthquake kit for your house yet, it's time to get going.


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