A Plan To Reduce Losses From Geologic Hazards In Utah

As a result of the landslides of 2005-06, Utah Governor Jon M. Huntsman, Jr., approved establishment of a working group to review the land-use-regulation process in Utah, recommend improvements, and identify how and where the State could assist. The Governor's Geologic Hazards Working Group (GHWG) was established in 2006 and met regularly from September 2006 through June 2007. This report highlights some of the 2005-06 landslides, reviews the establishment and activities of the GHWG, and presents the GHWG?s recommendations for reducing losses from geologic hazards.

Moab Valley and the contiguous Spanish Valley comprise a popular residential and recreational area in east-central Utah. Geologic processes that created the rugged and scenic landscape of Moab-Spanish Valley are still active today and can be hazardous to property and life. To address development in areas with geologic hazards, the Utah Geological Survey (UGS) conducted a geologic-hazards investigation to provide information to Moab City and Grand County to help guide development and reduce losses from geologic hazards. This report includes maps of Moab Valley and the northern and central parts of Spanish Valley that provide information on geologic hazards to assist homeowners, planners, and developers in making informed decisions. The maps show areas where hazards may exist and where site-specific studies are advisable prior to development. The maps are for planning purposes only, and do not preclude the necessity for site investigations. Site-specific studies by qualified professionals (engineering geologists, geotechnical engineers, hydrologists) should evaluate hazards and, if necessary, recommend hazard-reduction measures. Because of the small scale of the maps, some hazard areas are not shown; hazard studies are therefore recommended for all critical facilities (for example, hospitals, schools, fire stations), including those outside the mapped hazard areas.

This report documents how pertinent information about earthquake hazards along the Wasatch Front, Utah, was transferred to researchers, public officials, design professionals, land-use planners, and emergency managers as part of the U.S. Geological Survey's effort to mitigate the effects of earthquake hazards.

This study contains 10 1:24,000 scale GIS based geologic hazard maps that include liquafaction, surface fault rupture, flood hazard, landslides, rock-fall, indoor radon potential, collapsible soils, expanisve soils, shallow bedrock and shallow groundwater potential. Also includes a 73 page accompanying report that describes the hazards and provides background information on data sources, the nature and distribution of hazards, and possible hazard reducation measures.

Geologic hazards are naturally occurring processes that present a risk to life and property. This report provides information for the Monroe City area, in Utah's central Sevier Valley, to reduce losses from geologic hazards. Surficial-geologic mapping provides the basis on which individual geologic hazards are identified and mapped. Alluvial-fan and basin-fill deposits cover most of the map area. Other deposits consist of colluvium, artificial fill, spring travertine, and volcanic bedrock. The geologic hazards maps show where hazards may exist. The maps should be used to inform citizens and developers of potential risks and for local government officials to make prudent land-use planning decisions. The maps are general, and site-specific studies are needed to demonstrate site suitability prior to development. Typical risk-reduction methods for these geologic hazards generally include avoidance or engineering design to reduce the risk to an acceptable level.

The purpose of these guidelines for investigating geologic hazards and preparing engineering-geology reports, is to provide recommendations for appropriate, minimum investigative techniques, standards, and report content to ensure adequate geologic site characterization and geologic-hazard investigations to protect public safety and facilitate risk reduction. Such investigations provide important information on site geologic conditions that may affect or be affected by development, as well as the type and severity of geologic hazards at a site, and recommend solutions to mitigate the effects and the cost of the hazards, both at the time of construction and over the life of the development. The accompanying suggested approach to geologic-hazard ordinances and school-site investigation guidelines are intended as an aid for land-use planning and regulation by local Utah jurisdictions and school districts, respectively. Geologic hazards that are not accounted for in project planning and design often result in additional unforeseen construction and/or future maintenance costs, and possible injury or death.

Large, damaging earthquakes can happen in many parts of Utah. Therefore, when choosing where to live in this state, we should be aware of the earthquake risk. It is important to know what potential earthquake hazards exist in an area, and what action we can take to reduce the earthquake risk to ourselves and our families. This brochure introduces homebuyers and others to earthquake hazards so that informed choices can be made when selecting homes, building sites, or hazard-reduction measures.