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4 weeks ago
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A small town in Idaho has experienced 12 earthquakes in the last 24 hours.
The US Geological Survey (USGS) detected the seismic activity near Stanley, a town that played a key role in the gold rush during the late 1860s and 1870s.
The first earthquake struck at 4:33pm ET on Sunday, with the most recent recorded at 2:17pm today, ranging in magnitude from 2.5 to 3.4.
According to Michigan Tech University, quakes between 2.5 and 5.4 are typically felt by people and may cause minor damage. No damage has been reported from this swarm.
Stanley sits near the Sawtooth Fault, a 40-mile-long fault line running through central Idaho.
While geologically ancient, the Sawtooth Fault was only clearly identified in 2010.
It drew national attention after a magnitude 6.5 earthquake in 2020, one of the largest in Idaho in recent history, which was felt across several states.
Scientists estimate the fault could produce magnitude 7.0 or greater earthquakes, strong enough to cause serious shaking and damage hundreds of miles away.
Experts have called the Sawtooth Fault a 'sleeping giant' as it is dormant for long periods but capable of triggering a devastating earthquake when it awakens.
The US Geological Survey (USGS) detected the seismic activity near Stanley, a town that played a key role in the gold rush during the late 1860s and 1870s
The vast majority of earthquakes result from the constant movement of tectonic plates, which are massive, solid slabs of rock that make up the planetary surface and shift around on top of Earth's mantle — the inner layer between the crust and core.
As the tectonic plates slowly move against each other, their edges can get stuck due to friction and stress will build along the edges.
When that stress overcomes the friction, the plates slip, causing a release of energy that travels in waves through the Earth's crust and generates the shaking we feel at the surface.
The Sawtooth Fault is believed to be millions of years old and is part of the larger tectonic process that shaped the Basin and Range Province in the western US.
That region has been stretching and pulling apart for at least 17 million years, creating many north-south faults like the Sawtooth.
The last major earthquake to hit, a 6.5 magnitude, hit on March 31, 2020, but the area experienced aftershocks for at least three more months.
This was the second largest to hit the states, followed by a 6.9 magnitude in 1983.
Officials found that two months later, Stanley Lake's beach - a popular fishing and swimming spot - had collapsed due to the powerful tremor.
'One of the most dramatic effects of the earthquake was liquefaction at Stanley Lake. Ground shaking can weaken loose, water-saturated sediments, causing them to behave almost like a liquid,' the USGS said.
The first earthquake struck at 4:33pm ET on Sunday, with the most recent recorded at 2:17om today, ranging in magnitude from 2.5 to 3.4
At Stanley Lake, the sandy area near the inlet stream sank dramatically due to liquefaction.
'A popular beach at the inlet stream delta completely disappeared, and large cracks and sand boils formed along the shore.'
The event also triggered snow avalanches, debris slides and rock falls.
More than 47,000 people reported feeling shaking from at least six surrounding states.
Those included Montana, Washington, Utah, Nevada, Oregon and in parts of southern Canada.
After the earthquake, scientists used new lidar data to create a detailed map of the Sawtooth Fault.
Instead of one long crack, the map revealed that the fault is actually made up of several broken sections.
Using this map, researchers chose spots to dig trenches across the fault to study past earthquakes.
These trenches let scientists examine layers of soil that shifted during old quakes.
In one trench, geologists found signs of an earthquake that happened about 9,000 years ago.
More trenches are planned to help better understand the fault’s full earthquake history.
