Photographs from the 1983 Borah Peak, ID Earthquake Earthquakes in the Intermountain West are a mountain-building process as rock moves vertically along a fault.
Earthquakes typically occur repeatedly along the same faults.
The only man-made structure affected was the Doublespring Pass Road. The direction of movement along the fault was predominantly vertical, but the broken drainage ditch shows that some lateral movement also occurred. Rock fall and road damage made driving out impossible. They hiked 5 miles to Heard Lake where a ranger was looking for them. Click here for page 3 of the 1983 Borah Peak, ID earthquake photographs.