Posted in Idaho Nature November 21, 2017 by

On This Fateful Day Idaho Was Victim To Its Largest Earthquake Ever

We don’t worry about earthquakes here in Idaho very much. This type of natural disaster just doesn’t occur here very often (besides the bizarre swarm of earthquakes we experienced this summer). However, that doesn’t mean earthquakes never strike in the Gem State. You might remember the day that one of Idaho’s most violent and terrifying earthquakes occurred. This event may have happened 34 years ago, but the memory of it still lingers today.

On the morning of October 28, 1983, Idahoans awoke to a quiet and beautiful fall morning. This peace did not last for long. At 8:06 AM, to much confusion, the earth began to violently shake.
Erin Pass/Flickr
This event was one of the most intense natural disasters to strike Idaho and sadly resulted in two fatalities. The earthquake occurred in the Lost River Range. It began when a fracture 26 miles long and 7 miles deep surfaced along Mount Borah, the highest mountain in Idaho.
The epicenter of the quake was in a remote mountain region between Challis and Mackay. The earthquake was literally devastating during the 30 to 60 seconds that it lasted.
J Stephen Conn/Flickr
In Challis, two children were fatally crushed by falling debris as they walked to school that morning. Overall, it is estimated that the Challis-Mackay region suffered 12.5 million dollars in damage caused by the disaster.
Dozens of businesses and hundreds of homes were damaged during the quake. The town of Mackay, located about 50 miles from Challis, experienced the most damage.
James Holloway/Flickr
The majority of buildings in Mackay's downtown region were damaged and many were ultimately condemned. The fact that many of these buildings were built from materials such as brick, concrete, and stone contributed to this. The region was simply not prepared for an earthquake of such an incredible magnitude.
The earthquake resulted in what is called "surface faulting," which refers to breaks in the ground's surface caused by movement along a fault.
USGS Photo Library/Wikimedia Commons
These breaks made the ground look literally shattered, and some were measured to be up to 330 feet wide.
The quake left many dramatic, physical marks behind. The earthquake caused groundwater to gush up from beneath the earth's surface. The spewing fountains of water formed these crater-like features.
USGS Photo Library/Wikimedia Commons
Overall, the shock measured as a 7.3 magnitude on the Richter scale and was categorized as having a "violent" intensity.
J Stephen Conn/Flickr
Although the effects were most intensely felt in Challis and Mackay, the earthquake was felt over a large portion of the northwestern United States and even in parts of Canada. It's estimated that there were at least 20 aftershocks (all with a magnitude of 4.0 or larger) in the year following the initial shock.
This was by far one of the most devastating events to occur in our state. It happened over three decades ago, but the Borah Peak Earthquake is anything but forgotten.
MotoWebMistress/Flickr

Do you remember this devastating earthquake? It’s crazy to think this occurred in Idaho! Did you know about this Deadly Historical Fire That Turned Idaho Into An Apocalyptic Wasteland?