According to USGS, roughly 10 million people felt shaking from a strong earthquake which struck northern California near the Redwood Valley a short time ago. The magnitude 5.6 earthquake struck from a depth of 8.1 km northwest of Sacramento and San Francisco at 8:10 am local time; the National Tsunami Warning Center says there’s no threat of a tsunami from the earthquake along the U.S. and Canada West Coast or Hawaii.

The ShakeAlert Earthquake Early Warning system was activated for this earthquake, with millions receiving earthquake alerts right before it struck.

USGS says some damage is possible but the impact should be relatively localized. In addition to the 10 million people that felt shaking from the earthquake, USGS approximates that 60,000-70,000 felt moderate to very strong shaking from today’s earthquake. As of the publication of this article, more than 4,200 people logged what they felt with the USGS and their “Did you feel it?” website.

Aftershocks are forecast from today’s earthquake. USGS cautions, “If you feel shaking, drop, cover and hold on.” USGS says there’s an 89% chance of a magnitude 3.0 or greater after shock; a 40% chance of a magnitude 4.0 or greater earthquake, and a 7% chance of magnitude 5.0 or greater quake within the next week.

The National Tsunami Warning Center issued a brief Tsunami Information Statement shortly after the earthquake struck simply stating, “An earthquake has occurred; a tsunami is not expected.”

In the last 3 weeks, there were 82 earthquakes within 250 km of today’s earthquake. USGS has identified this event as the mainshock of an earthquake sequence, with 27 specific events tied to today’s earthquake sequence.