Hawk Rock Subsidence Feature 2004 - 2008 Interferogram
Geologic Hazards

Arizona Land Subsidence Monitoring Report

The Arizona Department of Water Resources has an excellent program to monitor a somewhat unique geologic hazard – land subsidence. Caused by compaction of valley sediments in areas of declining groundwater table, it can create […]


Crux Subsurface employees drilling geotechnical holes for the US 89 landslide investigation
Geologic Hazards

U.S. 89 Landslide Exploration

Specialty drilling contractor Crux Subsurface recently completed geotechnical drilling for Kleinfelder at the site of a large landslide near Page, Arizona. Crux completed 17 holes to depths up to 250 feet using a combination of […]

US89DrillingYouTubeThumb
Geologic Hazards

US 89 Bitter Springs Landslide Video Updates

US89DrillingYouTubeThumbSince I last posted about this landslide, ADOT has added several videos to their YouTube channel.  It’s clear that this highway is going to be closed for the long term.  ADOT and their on-call geotechnical consultant tasked with this project, Kleinfelder, are currently drilling boreholes to attempt to characterize the failure surface and determine what the geometry of the failure surface is.  They are installing at least 10 inclinometers to try to determine the location of the slip plane or planes at depth and they have two extensometers to measure if any additional movement occurs.  They are also performing LIDAR surveys as well. Check out the videos below.

Initial ADOT Video Describing the Failure

Click through for the videos!

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Arizona Geology Map
Available Resources

Online Geological Map of Arizona

The Arizona Geologic Survey has released an online version of the geologic map of Arizona. It uses a Google Maps interface, and allows you to zoom in on any area in the state to view […]


SR 87 Landslide Between Payson and Phoenix, March 2008
Geologic Hazards

SR 87 Landslide Coverage and Update

SR 87 Landslide Between Payson and Phoenix, March 2008Back 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)

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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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