From the AZGS Document Repository: These guidelines provide professionals evaluating site-specific conditions in areas known or suspected to be subsiding with a standardized minimum level of investigation for land-subsidence and earth-fissure hazards. The guidelines do […]
Carbon sequestration is a hot topic these days, and the Arizona Geologic Survey (AZGS) is working with a consortium of public and private agencies and non-profits to evaluate the potential of CO2 storage in Cenozoic […]
A new Google Maps based interface for viewing earth fissures in four Arizona counties has been launched by the AZGS. Earth fissures are a serious geologic hazard in Arizona where they have been known to […]
Last week was the annual American Council of Engineering Companies of Arizona Roads and Streets Conference in my home town of Tucson, Arizona. Its a transportation themed conference as you might guess, but there are usually a few geotechnical-type presentations. This year, there was an excellent presentation on the SR 87 Landslide that occurred about 1-year ago on the highway between Phoenix and Payson. The presentation was given by Keith Dhalen, PE with AECOM , Wayne Harrison, RG also with AECOM and Scott Neely, PE with Terracon . Read on for my recap of the presentation. (Photo by ADOT via AZGS)
The East Valley Tribune published an extensive set of news features on earth fissures in their Sunday edition, including timeline, maps, videos, and an animation of how fissures form.
KPHO, CBS channel 5 in Phoenix, also has a nice video segment with great aerial shots of the 2005 fissure in Chandler Heights that triggered the recent interest in this hazard.
Here is the video he was referring to.
Yesterday the Arizona Geologic Survey (AZGS) released the first two of their 1:12,000 series earth fissure maps to the general public. The mapping program, perhaps the first of its kind in the country, came about after an earth fissures opened up in 2005 near Queen Creek, AZ, southeast of metropolitan Phoenix received much media attention. As a result, the Arizona Legislature passed House Bill 2639 of the 2006 Legislative Session that tasked the AZGS with mapping earth fissures and providing the data to the State Land Department for eventual delivery to property owners in Arizona. More after the break. (At left, the Apache Junction study area map, AZGS)
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)
According to Lee Allison’s Blog (Lee is the head of the Arizona Geological Survey and the Arizona State Geologist), the AZGS has released earth fissure maps of 4 Arizona Counties suitable for planning purposes. Read on for more details.