Earthquake shakes Boise on Saturday night. Here’s how it compares to our recent quakes
Central Idaho’s strongest earthquake of the year shook the Boise area on Saturday night — nearly simultaneous with the end of the Boise State football team’s loss to Oklahoma State at Albertsons Stadium.
The 4.0-magnitude earthquake was reported at 10:18 p.m. by the U.S. Geological Survey.
A second, smaller quake happened 20 minutes later — recorded at 2.6 magnitude. A third, at 3.5, was recorded at 11:06 p.m. and a fourth, at 3.4, at 11:18 p.m. There were two more quakes shortly before midnight, recorded at 3.0 and 3.4.
Saturday’s first quake was the strongest centered near Stanley since November 2020, according to the USGS. There have been more than 1,000 earthquakes of 2.5 magnitude or higher in that area in the past year and a half.
A 6.5-magnitude earthquake struck Idaho on March 31, 2020 — the second-strongest quake ever recorded in Idaho. The state has been shaking off and on ever since, with quite a few that have been felt in the Boise area. The first one Saturday was among the strongest shakes in Boise since the the day of the original quake.
The last one larger than Saturday’s quake was a 4.1 on Nov. 25, 2020. Only 21 of the aftershocks have reached 4.0.
Saturday’s first quake was centered about 11 miles northwest of Stanley. That’s the same general area that has been producing earthquakes for nearly 18 months now. The magnitude was originally set at 3.9 but was increased to 4.0 shortly after.
Scientists have pointed to the Sawtooth Fault — a 40-mile long fault discovered about a decade ago — as the likely origin of the earthquakes. Geologists say Idaho is a very seismically active state, but it hasn’t been the subject of much study until recently. Last year, experts said Idahoans can expect aftershocks to continue for years.
Central Idaho’s 4.0 or larger quakes since March 31, 2020
4.0, Sept. 18, 2021
4.1, Nov. 25, 2020
4.1, Nov. 15, 2020
4.1, Nov. 13, 2020
4.0, Nov. 6, 2020
4.4, Sept. 8, 2020
4.0, Sept. 8, 2020
4.2, Aug. 7, 2020
4.1, July 10, 2020
4.6, June 24, 2020
4.2, June 14, 2020
4.2, June 9, 2020
4.4, May 21, 2020
4.4, May 13, 2020
4.1, April 20, 2020
4.1, April 11, 2020
4.0, April 3, 2020
4.0, March 31, 2020
4.4, March 31, 2020
4.8, March 31, 2020
6.5, March 31, 2020
