A large landslide has closed SR 14 east of Cedar City, Utah. UDOT expects that the road will be closed for up to 2 weeks for cleanup and to ensure that the slope is safe. Boulders up to an estimated 20 tons are now blocking the road and will likely need to be blasted down to a smaller size. A UDOT spokesman interviewed on the video shown after the break estimate the size of the slide at 700 to 800-ft long and 10 to 12-ft thick.
This is definitely the season for landslides, mudslides, debris flows and other mayhem in Oregon and elsewhere in the pacific northwest. It seems like every time I turn around there is another Google Alert in my inbox about a landslide related issue in that area. Having a hard time keeping up with it all, I decided to try something new. Click through to see a map of automatically updated landslide news in Oregon. Lets call it a Beta…so we’ll see if it works out. If it does, maybe I’ll try something similar for other areas or other items that tend to make it into the news. (Photo by Ross William Hamilton/The Oregonian)
Back in March of 2008 there was a landslide that closed SR 87 in between Phoenix, Arizona and Payson. It’s been of great interest to me since it is in my state and affected a highway. I was hoping my firm (NCS Consultants, LLC) might be asked to work on the remediation through our on-call contract but it didn’t happen. Its probably for the best, it sounds like it’s been a troublesome geotechnical engineering problem. Fast forward to last week, and the slide area was in the news again because the slope is still moving and apparently causing some additional deformation of the roadway. (Photo by ADOT)
I had heard about this a while ago through our ADOT contacts, but I make it a policy not to take advantage of my contacts through my day job for GeoPrac.net content (not without permission anyway). So I didn’t want to blog about it until it hit the mainstream media. Last week, the Arizona State Geologist blogged about the SR 87 slide moving again, as did Ken through his AEG Arizona Section blog. It was even covered on one of my favorite blogs, Dave’s Landslide Blog. I finally have a chance to wade through these blog posts and some of the reports and videos to present a summary of the situation, available information and offer my own perspective. (More after the break)
Dr. Dave has posted links to a few scary landslide videos from the recent heavy rains affecting the Santa Catarina province of Brazil. This latest one shows an ambulance being swept off a road by a “small” landslide. The ease with which the vehicle is moved is quite impressive. It didn’t appear that anyone was injured in this particular landslide but I’m sure there might have been some underwear changing involved. Elsewhere in the region people have not been so lucky and there is a heavy death toll. Click through for two videos.
From the USGS Newsroom:
USGS scientist Ken Hudnut fills us in on how science created the theoretical magnitude 7.8 earthquake behind the Great Southern California ShakeOut—the largest earthquake preparedness drill in U.S. history, coming Nov. 13—and what such an earthquake would do to downtown Los Angeles.
Seems like they did it right wiith this study. They had multiple teams independenlty come up with the ground shaking model, then had different structural engineers who are experts in seismic design of large buildings review the tall buildings in the L.A. area for the design earthquake. They say that buildings would likely come down in the 7.8 magnitude event. Click through to watch the video interview from the USGS.
A report has been released by the NYSDOT on the Scoby Hill Landslide which has impacted a 4.2-mi improvement project of Route 219. The report, dated May 20, 2008 was headed to an FHWA peer review panel.
The Feds were call in to help because of the unusual nature of the landslide. The slip surface is very deep, approximately 30-m (100-ft) below the surface and below all of the design phase investigations. And the remolded shear strength of the silty clay forming the slip surface was only 12-14 degrees.
Read on for more details of the slide. (Photo by NYSDOT)
That is the title of a Seattle Post-Intelligencer article on post-Katrina levee issues in New Orleans (by way of ASCE Smart Brief). I think the article is somewhat sensationalized, but they do cite some interesting parallels between the levee reconstruction efforts made after Katrina and the levee construction/reconstruction that occurred after Hurricane Betsy in 1965.
The article also discusses a recent US Army audit with some disturbing although not unexpected findings:
An initial September 2010 target to complete the $14.8 billion in post-Katrina work has slipped to mid-2011. Then last September, an Army audit found 84 percent of work behind schedule because of engineering complexities, environmental provisos and real estate transactions. The report added that costs would likely soar.
A more recent analysis shows the start of 84 of 156 projects was delayed – 15 of them by six months or more. Meanwhile, a critical analysis of what it would take to build even stronger protection – 500-year-type levees – was supposed to be done last December but remains unfinished.
Earlier this month, there was a massive slope failure on the "Sea to Sky" highway in British Columbia. It is interesting to note that this same area had a large rockslide in 1965, and a photo of this failure is featured on the cover of the classic text, Rock Slope Engineering by Hoek and Bray. The media played up the aspect that this highway is one of the only ways to access the site of the 2010 Winter Olympic games hosted by Vancouver.
The composite image above shows the book cover and the recent rockslide event (Photo credit: Erik Eberhardt of the University of British Columbia by way of Dave’s Landslide Blog). Dave has done a fabulous job collecting photos, facts and links from around the web. In a follow up post, he added some additional photos and discussion. I recently came across an article that described how the highway originally was slated to have a tunnel bypassing the slide, but that the price tag of $200 million (CAN?) for a 1-km stretch killed the project.
There have been a number of reports on the flooding in Supai Canyon, near the Grand Canyon this past weekend. I think the best description of the event and the subsequent rescues was from the AZ211 website which I found by way of the Arizona Geology Blog (quoted after the break). The flood was impressive. I hope the areas near Havassu Falls and Mooney Falls were not too heavily damaged. I was fortunate enough to hike and camp that location back in College, the travertine is just amazing and makes the water so green. Mooney Falls and the area downstream are particularly breathtaking. [Photo credit: National Parks Service]
Many reports I’ve seen attribute the flood the result of the failure of the Redlands Dam. But again, the Arizona Geology Blog quotes the National Park Service as saying that the dam is a minor one meant to create a pond for livestock and wasn’t a significant factor in the flooding. The latest reports I saw was that 11 hikers who were missing were located today (by way of Geology.com)
Geology.com pointed out a very nice PDF version of a Power Point presentation by the North Carolina Geologic Survey on their landslide hazard mapping efforts in western North Carolina. The presentation was dated August 1 of last year. The NCGS also has their landslide mapping products available for download, and those so inclined can download the GIS data sets as well. (Photo by NCGS)
Copyright © 2007-2020 by Randy Post