“I’m not an expert on the 1983 Borah Peak earthquake, but I did a bit of searching regarding the question. It appears that the figure of 14 feet comes from the maximum observed slip, not ‘raising’ the mountain,” Mencin said. “In 1983, the geodetic techniques easily available would have been constrained to measurements at and near the visible fault rupture, not in the far field. In the last 20 years space based geodesy has allowed us to make far field measurements, like the height of mountain or change in the height of a mountain, with relative ease.”
“I don’t think anyone knows that question exactly. The methods available at the time would have been quite costly and they would have to have had a precise height before the earthquake. It’s possible someone attempted to measure this but I can’t find any references.”
According to the Idaho Geological Survey, at 5:52 p.m. on March 31, a magnitude 6.5 earthquake occurred about 19 miles northwest of Stanley. Seismic instruments indicate the earthquake originated at a depth of 6.2 miles.
The USGS tectonic summary reports: “…This earthquake occurred within the Intermountain Seismic Belt, a prominent zone of recorded seismicity in the Intermountain West, and is within the western part of the Centennial Tectonic Belt, an area of southwest-northeast extension north of the Snake River Plain. The quake is about 16 km [nearly 10 miles] north-northeast of the Sawtooth fault, a 60-km-long [37 miles] normal fault that extends along the eastern base of the Sawtooth Range.”
