Arizona State Geologist Lee Allison provides three new updates on the landslide that destroyed a portion of Highway 89 just south of Page, Arizona:
This post provides a look at history of the area. A 1917 USGS Professional Paper 93, “Geology of the Navajo Country” points to landslides at the specific area that recently failed.
“While the Arizona Department of Transportation is still trying to determine what exactly happened to cause the ground to shift beneath US 89 Wednesday, the agency continues to assess the significant damage to the highway. Geotechnical engineers are currently evaluating the stability of the mountain slope, approximately 25 miles south of Page.”
This report, with a new video, shows that cracks are more extensive than initially thought. They extend a couple of hundred feet downslope from the US89 guard rail indicating that the highway repair and remediation actions will have to cover a much larger area than just the immediate roadway.