Qualla: 1983 Borah Peak Earthquake

1983 Borah Peak Earthquake: Introduction

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. At 8:06 AM on October 28, 1983, the ground beneath central Idaho broke. A magnitude 6.9 earthquake, the largest in Idaho's recorded history, ripped a 21-mile gash along the western face of the Lost River Range. Two children died in Challis when a storefront collapsed on them. Eight states felt the shaking. And 150 miles east, Old Faithful geyser in Yellowstone began keeping different time, its eruption intervals mysteriously lengthened by forces traveling through the deep rock.

Image: Mikenorton | CC BY-SA 3.0

1983 Borah Peak Earthquake: The Earth Splits

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit Qfl247 (talk), CC BY-SA 3.0. The rupture left its signature visible from the air. A 21-mile zone of fresh fault scarps traced a northwest-trending line along the Lost River Range, some scarps stretching 14 feet wide. Between West Spring and Cedar Creek, the ground had shattered into tilted blocks several met...

Image: Qfl247 (talk) | CC BY-SA 3.0

1983 Borah Peak Earthquake: Fountains of Sand

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit Qfl247 (talk), CC BY-SA 3.0. Near Chilly Buttes in Thousand Springs Valley, something strange erupted from the ground immediately after the main shock. Artesian fountains burst through the surface, gushing groundwater that carried sand and sediment upward in violent plumes. These sand blows formed small crat...

Image: Qfl247 (talk) | CC BY-SA 3.0

1983 Borah Peak Earthquake: Main Street in Ruins

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit Qfl247 (talk), CC BY-SA 3.0. The towns of Mackay and Challis bore the earthquake's fury. Eleven commercial buildings and 39 homes sustained major damage; another 200 houses suffered lesser harm. Mackay, southeast of Challis along the Lost River, experienced the worst destruction. Most of the large buildings ...

Image: Qfl247 (talk) | CC BY-SA 3.0

1983 Borah Peak Earthquake: Old Faithful's New Rhythm

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit Qfl247 (talk), CC BY-SA 3.0. One hundred fifty miles east of the epicenter, in Yellowstone National Park, the earthquake made itself known in an unexpected way. Old Faithful geyser, famous for its predictable eruptions, began keeping different time. The intervals between eruptions lengthened noticeably in th...

Image: Qfl247 (talk) | CC BY-SA 3.0

1983 Borah Peak Earthquake: Aftershocks and Memory

Fri, 23 Jan 2026 00:00:00 GMT

Photo credit SelfCorrection, CC BY-SA 4.0. The shaking did not end on October 28. Aftershocks continued for a full year, keeping residents on edge and reminding them that the earth beneath their feet remained unsettled. Nearly ten months after the main event, a magnitude 5.4 aftershock struck, powerful enough to make news...

Image: SelfCorrection | CC BY-SA 4.0