Project Related

Devil’s Slide Tunnel, Project Updates and Geotechnical Info

Devil’s Slide is an infamous landslide along California’s Highway 1 or Pacific Coast Highway near Pacifica, just south of the San Francisco Bay area. Caltrans’ Devil’s Slide Tunnel project is an effort to bypass that slide and make the heavily traveled roadway safe for drivers and to eliminate the maintenance and traffic hassles caused by slope failures blocking the road. We first covered the project back in September of 2007 when the tunnel portion of the project commenced. In that post, you can find a Google Earth KML File showing the location of the tunnels and the new bridges associated with the project. In this post, I’ll provide you with some updated progress information as well as some background on the geotechnical and other aspects of the project. More links and videos are at the end of the post.  (Photo by Kim Komenich, San Francisco Chronicle). […]

Geologic Hazards

Pittsburgh Area Has 49 Active Landslides

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)

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Geologic Hazards

Sichuan Earthquake Update

[Updated May 30, 2008] I forgot to publish this post to the front page, whoops! The two links still have excellent information. In particular, Dave’s Landslide Blog has coverage of the many landslide lakes and the efforts to breach some of them. [/Update]

The latest numbers according to AFP, Worldwide News Agency, is 71,000 dead, missing or buried and over 5 million homeless. There were many victims that were buried by landslides and rockfall. In the past few days 200 rescue workers have been buried by mudslides.

For more coverage on landslides related to the earthquake, I recommend Dave’s Landslide Blog. Geology.com also has very comprehensive coverage as well. (AFP Photo)

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Geologic Hazards

105th Anniversary of Frank Landslide

Fellow geo-blogger David Petley of Durham University posted today about the 105th anniversary of the Frank Landslide in Canada. The slide had an estimated volume of 30 million cubic meters and took all of about […]

Geologic Hazards

Landslide on Arizona SR 87 Closes Highway

On March 21, 2008 a landslide caused the closure of Arizona State Route 87 between Payson and Phoenix near mile post 224. So far there are no official estimates as to the size, but based on aerial photos, it appears to be at least 50,000 sq-ft in plan. The offset at the head scarps was approximately 2-meters (6.6-ft) according to AZGS Geologists on site. It appears to have been a rotational slide as the toe of the landslide heaved the southbound roadway up by as much as 1-meter (3.3 ft). There was an existing soil-nail retaining wall on the slope that was destroyed by the slide as well.  Lateral deformations can be seen in photos of the median barrier and the roadway striping. The deformations extended into the northbound lanes as well. More photos and links after the break. (Photo by ADOT)

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Geologic Hazards

Landslide Blocks Road in LA, Inconveniences UCLA Hoops Fans

Mud and debris from a small landslide closed a portion of Sepulveda Blvrd. In Westwood California on Thursday. The slide took out at  least one local resident’s backyard and was large enough to block several lanes of the roadway with debris up to 6-ft high in addition to knocking out several power poles and disrupting service. The material was cleared up by 10pm but not before it cause some inconvenience to UCLA basketball fans on their way to watch their team beat Stanford. The LA Times reports that there were questions about possible broken water lines, of course it is the old "chicken or the egg" argument that’s been seen before (including on a recent landslide) about whether the broken water lines contributed to the landslide, or the landslide caused the water line breaks. (Photo by Al Seib / Los Angeles Times)

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Available Resources

Geologic Hazard Photos

The National Geodetic Data Center (NGDC) of NOAA has an online collection of photos of various geologic hazards. Many of the photos are from older sets of 35mm slides that have been digitized. They are free to use provided you credit the photographer and the NGDC as the source. The would be really useful for educators and for powerpoint presentations. The only drawback is that they are in TIF format and some of them could use some retouching. (Photo by University of Colorado, made available by NOAA/NGDC)

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No Picture
Geologic Hazards

Teenage Girl Buried Alive in Beach Bluff Landslide

A teenage girl strolling on the beach in Pacifica, California was buried alive by a landslide. She was buried up to her chest, and a passer-by dug her out with his bare hands while more soil and rock fell around them. Story at KTVU San Francisco. See a nice oblique aerial photo of the beach prior to the landslide here. Those slopes don’t look particularly stable to me but what do I know? 

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Geologic Hazards

Allegations: Oregon Not Forthcoming With Landslide Hazard Information

Folks in Oregon are angry about a recent landslide and debris flow that closed Highway 30 and destroyed property in the town of Woodson. (Here is a powerpoint presentation by Bill Burns of the Oregon Department of Geology and Mineral Industries showing how the event happened). Some rather stinging allegations are being made that politicians withdrew a landslide hazard map from general use in 2002 for political reasons. That map or another one had characterized the area effected by the December 2007 debris flow as a "very high" or "extreme" risk of landslides. A very interesting article. 

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Geologic Hazards

More Movement on La Jolla Landslide

For those of you following the landslide in residential La Jolla California known as the Soledad Mountain Road landslide, it made the news again a couple days ago when a section of the slide re-activated and slid 10-ft down the hill. Doesn’t sound like too big of a deal to me, no additional houses damaged. I’m curious how it related to the shear pins they installed a couple of months ago.

Additionally, the San Diego City Attorney has released a report detailing the sequence of events leading up to the landslide. One interesting note is that the Mayor of San Diego is in hot water with the City Attorney’s office for hiring outside legal council to handle the legal aspects of the landslide. According to the City Attorney’s office, he wasn’t allowed to do that, but so far the City Attorney hasn’t stepped in to force the outside attorney(s) to drop the case saying it would open the City up to even more liability.

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