An article by the NZ Herald reports that recommendations for slope monitoring and early warning made by a geotechnical consulting firm in a report 2 years before the initial failure were not adopted by Auckland Transport. The Birkenhead landslide initially took out 25 parking spaces in a retail area in October of 2017, and a larger landslide in November of the same year took out a micropile or other drill rig working to stabilize the site. Local officials defended the decision, indicating that they instead opted for regular site visits and visual observation of cracks noted in the report. The initial recommendations by GHD Engineers included the monitoring as a minimum, and also recommended several stabilization options in the range of $500k. The current estimates to repair the landslide are $14M to $24M.
A massive rockslide closed a busy interstate route last week near the border between Tennessee and North Carolina in Pigeon River Gorge. This area has had landslide problems in the past. In 1997 a rockslide in the same area closed the freeway for approximately 3 months. (Photo from Landslides Under a Microscope Blog, original source not cited)
I have yet to see volume estimates, but The Charlotte Observer quoted a highway patrol officer who was at the scene:
He said the roadway is covered by a gigantic mound of debris, from pebbles up to house-sized boulders. The pile is 40 to 50 feet high, Williamson estimated, and hundreds of feet long.
More info and video after the break. […]
The Pittsburgh area has 49 active landslides or retaining wall failures in 29 neighborhoods according to a Pittsburgh Public Works Department survey. The estimated cost to fix 24 of those issues effecting public land is $7.4 million, which the City doesn’t have. Story source: Pittsburgh Live by way of Geology.com. (Map by BOB NEWELL/TRIBUNE-REVIEW)