Magnitude 5.6 quake northwest of Skwentna felt across Anchorage and Mat-Su

A magnitude 5.6 earthquake struck 43 miles northwest of Skwentna at 8:50 p.m. Saturday, and residents across Anchorage and the Mat-Su Valley reported feeling it, the Alaska Earthquake Center said after reviewing the event. The center listed the quake as a significant event. For residents, what matters about a widely felt quake is less the magnitude at the epicenter than whether shaking reached populated areas and whether any damage or continuing hazard follows.

The quake struck at a depth of 6 miles, according to the center's event page. "Residents throughout Anchorage & Mat-Su reported feeling this earthquake," the center said in its review posted Saturday. The center's listing carries no report of damage so far.

One Anchorage resident posted on Reddit that the shaking amounted to a "little wiggle giggle of the earth," adding, "Had a nice wobble in Anchorage."

Smaller quakes were logged in the same ground the same day. At least four were recorded west-northwest of Skwentna, ranging from magnitude 1.3 to magnitude 2.4, all within a few miles of the larger quake's location. A magnitude 1.3 event was also logged just north of Big Lake.

Alaska sees frequent seismic activity. The Alaska Seismic Hazards Safety Commission reports the state accounts for 11 percent of the world's recorded earthquakes, averages about 1,000 located quakes a month, and sees a magnitude 8 or larger roughly every 13 years. FEMA estimates Alaska has the second-highest average annualized earthquake-loss ratio in the country. Alaska News previously covered a similar cluster southwest of Anchorage and the Kenai Peninsula Borough, when the center confirmed a magnitude 4.2 near Hope and a separate magnitude 5.1 south of Kalifornsky.

The center is also developing a system to give Alaskans seconds of warning before major shaking arrives.

People who felt Saturday's quake can submit a felt report through the center's event page at earthquake.alaska.edu. Those reports help the center collect impact information from the public and refine maps of where shaking was strongest.