An earthquake struck just outside of Malmstrom Air Force Base in Montana, which oversees a large network of intercontinental ballistic missile (ICBM) silos spread across the state.
The US Geological Survey (USGS) recorded a 4.2 magnitude quake at 12:41pm MT (2:41pm ET), just seven miles outside of the center of the base located in Great Falls.
More than 200 people in the area reported shaking, with one saying on X: ‘We just had an earthquake, holy cow, our building shook, looks like we were very close.’
Another resident shared: ‘Just had a big earthquake here in Montana. Holy s***, that was scary.’
The USGS warned there is a 27 percent chance of a magnitude 3 or greater aftershock striking in the same area in the next week. There is also a six percent chance of another 4 magnitude or higher tremor hitting in the same timeframe.
While Montana is not a major earthquake hotspot, the region lies along the Intermountain Seismic Belt, a zone of faults capable of producing moderate quakes.
The quake occurred near areas that house hardened missile silos and launch control facilities. There are approximately 150 active ICBM silos throughout Montana.
Military officials have not issued a statement about the earthquake or whether any damage has occurred to the silos.
‘Damaging earthquakes can occur in the future, so remember to: Drop, Cover, and Hold on,’ the USGS said in an alert.
‘No one can predict the exact time or place of any earthquake, including aftershocks. Our aftershock forecasts give us an understanding of the chances of having more earthquakes within a given time period in the affected area.’
The earthquake hit just six miles below the surface. Shallow earthquakes tend to be more destructive because their energy reaches the surface with little loss, producing stronger shaking.
In contrast, deeper quakes spread their energy over a wider area, often lessening the impact on buildings and people.
Susan Hough, a US Geological Survey seismologist, previously told AP that shallow quakes can feel like ‘a bomb directly under a city.’
Montana residents reported feeling light tremors as far north as Shelby, about 85 miles from Great Falls.
Weak shaking was also felt in Helena, the state capital. Officials have not yet confirmed whether the quake caused any damage.
Malmstrom Air Force Base maintains a vast number of silos across 13,800 square miles of central Montana, making it the largest complex of nuclear arms in the western hemisphere.
It is one of three bases that together house the country’s arsenal of 400 Minuteman III missiles.
The silos in Montana are run by the 341st Missile Wing, whose mission is to provide ‘lethal combat capability by delivering long-range precision nuclear strikes within a moment’s notice.’
The closest it has come to doing that was during the Cuban Missile Crisis.
Each missile is 60 feet in length and weighs almost 80,000 pounds, with a range of 8700 miles.
If the launch order comes, it would race into the air from the silo in less than four seconds, climbing 70 miles above Earth before reaching its target on the side of the planet in 25 minutes, before unleashing twenty times the explosive power of the bomb that killed 140,000 people in Hiroshima.
