Separating fault line prompts closure on Hwy 67 southeast of Granite Falls, MN
The Minnesota Department of Transportation is warning drivers of a fault line that began separating under the road on Highway 67 southeast of Granite Falls, Minnesota.
According to MnDOT, a fault line began separating under the road on Highway 67, which sits between the Yellow Medicine and Minnesota Rivers.
Officials say the fault line has been separating at a rate of about one inch per day. This means visitors heading to the Upper Sioux Agency State Park must come from the north on southbound Hwy 67.
MnDOT returned to the site a month later to find that the road had expanded.
Below is a photo of Hwy 67 taken on May 24, 2019:
In the meantime, a detour has been set up to get to the main entrance of the Yellow Medicine Campground.
According to MnDOT this closure and detour is expected until Fall 2019.
“The prevailing idea is that the movement of the North American plate away from the mid-Atlantic ridge toward the subduction zones on the Pacific Coast set up a subtle, but pervasive stress in the interior of the continent,” Chandler said. “That stress might be sufficient to jostle old faults that formed many millions or billions of years ago in Minnesota’s case, that remain, even though the tectonic forces that built those faults are long since quiet.”
The supposed biggest quake recorded in Minnesota history happened in Long Prairie in the 1860s. Its magnitude was an estimated 5. Estimated, because seismographs weren’t used to measure a significant Minnesota earthquake until later.