On the afternoon of December 12, 2013, a large, joint-controlled block of the Shinarump Conglomerate Member of the Chinle Formation, with an estimated volume of almost 1400 cubic yards and weighing about 2700 tons, detached from the cliff face at the top of the Rockville Bench in Rockville, Utah. The block fell on to the steep Moenkopi Formation slope below the cliff, and shattered into numerous cobble- to very large boulder-sized fragments. The fragments moved rapidly downslope before striking and destroying a house, detached garage, and car at 368 West Main Street in Rockville. The two occupants in the house were killed. The purpose of this 20-page investigation wast to document the characteristics of the fatal rock fall; evaluate future rock-fall hazard at and near the site; and provide recommendations for homeowners, the Town of Rockville, and other officials to consider in managing rock-fall risk. Although the first fatal event, this rock fall is the sixth large rock fall within the Town of Rockville in the 35 years prior to December 12, 2013. Five of those events occurred within the past nine years, and at least three of those struck and damaged structures at the base of the Rockville Bench.
This 116-page report presents the results of an investigation by the Utah Geological Survey of land subsidence and earth fissures in Cedar Valley, Iron County, Utah. Basin-fill sediments of the Cedar Valley Aquifer contain a high percentage of fine-grained material susceptible to compaction upon dewatering. Groundwater discharge in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley as much as 114 feet since 1939. Groundwater mining has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer, which has caused the land surface to subside, and a minimum of 8.3 miles of earth fissures to form. Recently acquired interferometric synthetic aperture radar imagery shows that land subsidence has affected approximately 100 mi² in Cedar Valley, but a lack of accurate historical benchmark elevation data over much of the valley prevents its detailed quantification. Continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form which may eventually impact developed areas in Cedar Valley. This report also includes possible aquifer management options to help mitigate subsidence and fissure formation, and recommended guidelines for conducting subsidence-related hazard investigations prior to development.
This will help us customize your experience to showcase the most relevant content to your age group
Please select from below
Login
Not registered?
Sign up
Already registered?
Success – Your message will goes here
We'd love to hear from you!
Thank you for visiting our website. Would you like to provide feedback on how we could improve your experience?
This site does not use any third party cookies with one exception — it uses cookies from Google to deliver its services and to analyze traffic.Learn More.