Current Issue Contents:
• The Uinta Mountains: A Tale of Two Geographies
• In Memoriam: Lehi F. Hintze
• Students Fill the GIS Gap
• The 2014 Crawford Award
• GeoSights: Roosevelt Hot Springs Geothermal Area, Beaver County
• New Publications
• Teacher’s Corner
• Core Center News
• Glad You Asked: What are keeper potholes & how are they formed?
By: William R. Lund
The Utah Geological Survey has revised and updated the Utah fault database used with the Federal Emergency Management Agency’s Hazus Earthquake Model. The Hazus Earthquake Model loss estimation software is designed to produce loss estimates for use by federal, state, regional, and local governments in planning for earthquake risk mitigation, emergency preparedness, response, and recovery. The model’s loss estimates are based on a scenario earthquake on a fault in an area of interest. This revised Hazus Utah fault database provides parameters for scenario earthquakes on significant Utah Quaternary-active faults statewide and for select faults/fault sections in adjoining states. The previous Utah Hazus fault database contained 27 Quaternary faults/fault sections taken largely from fault sources on the United States National Seismic Hazard Maps. This revised database expands the Utah Hazus fault database to include all known Late Quaternary and younger faults/fault segments capable of generating a ≥M 6.75 earthquake in Utah, and includes 82 Quaternary-active faults/fault segments, and nine credible multisegment rupture scenarios.
By: V.E. Langenheim, R.Q. Oaks, H. Willis, A.I. Hiscock, B.A. Chuchel, J. Rosario, and C.L. Hardwick
A new isostatic residual gravity map of the Tremonton 30′ x 60′ quadrangle of Utah is based on compilation of preexisting data and new data collected by the Utah and U.S. Geological Surveys. Pronounced gravity lows occur over North Bay, northwest of Brigham City, and Malad and Blue Creek Valleys, indicating significant thickness of low-density Tertiary sedimentary rocks and deposits. Gravity highs coincide with exposures of dense pre-Cenozoic rocks in the Promontory, Clarkston, and Wellsville Mountains. The highest gravity values are located in southern Curlew Valley and may be produced in part by deeper crustal density variations or crustal thinning. Steep gradients also coincide with the margins of the Promontory Mountains, Little Mountain, West Hills, and the eastern margin of the North Promontory Mountains and may define concealed basin-bounding faults.
By: Christopher B. DuRoss and Michael D. Hylland
The Salt Lake City segment (SLCS) of the Wasatch fault zone and the West Valley fault zone (WVFZ) are Holocene-active faults that have evidence of large-magnitude (M ~6-7) surface-faulting earthquakes. Paleoseismic research trenches at the Penrose Drive site on the SLCS and Baileys Lake site on the WVFZ provided data that shed light on the faulting behavior and interaction of these graben-forming fault systems. Numerical age control (22 radiocarbon samples 23 optically stimulated luminescence samples) and OxCal modeling of six or seven surface-faulting earthquakes on the SLCS and four earthquakes on the WVFZ helped refine the earthquake chronologies for these faults and allowed a comparison of the chronologies to evaluate fault interaction. The chronologies, as well as vertical displacements, support a model of coseismic fault movement.
By: Hellmut H. Doelling and Paul A. Kuehne
The Klondike Bluffs 7.5′ quadrangle covers a large part of Arches National Park and encompasses colorful bedrock strata ranging in age from Pennsylvania Paradox Formation to Cretaceous Mancos Shale. Salt diapirs are common throughout the area, and the Salt-Cache Valley Salt Structure is the most prominent structure, with several additional salt structures present, including the Salt Wash and Courthouse synclines and the Elephant Butte folds. Scenic resources in the area showcase joints, fins, grabens above salt wells, and the highest concentration of arches in the world.
This CD contains geographic information system (GIS) files in ESRI file geodatabase and shapefile formats. A geologic map at 1:24,000 scale and a 31-page booklet are also included in PDF format. The latest version of Adobe Reader is required to view the PDF files.
By: Hellmut H. Doelling and Paul A. Kuehne
The Mollie Hogans 7.5′ quadrangle covers a large part of Arches National Park and encompasses colorful bedrock strata ranging in age from Pennsylvanian Paradox Formation to Cretaceous Mancos Shale. Salt diapirs are common throughout the area, and the Salt-Cache Valley Salt Structure is the most prominent structure, with several additional salt structures present, including the Salt Wash and Courthouse synclines and the Elephant Butte folds. Scenic resources in the area showcase joints, fins, grabens above salt walls, and the highest concentration of arches in the world.
This CD contains geographic information system (GIS) files in ESRI file geodatabase and shapefile formats. A geologic map at 1:24,000 scale and a 31-page booklet are also included in PDF format. The latest version of Adobe Reader is required to view the PDF files.
By: Hellmut H. Doelling and Paul A. Kuehne
The Windows Section 7.5′ quadrangle covers a large part of Arches National Park and encompasses colorful bedrock strata ranging in age from Pennsylvanian Paradox Formation to Cretaceous Mancos Shale. Salt diapirs are common throughout the area, and the Salt-Cache Valley Salt Structure is the most prominent structure, with several additional salt structures present, including the Salt Wash and Courthouse synclines and the Elephant Butte folds. A one-mile-wide zone of faults is located in the Windows Section northeast of the Moab fault. Scenic resources in the area showcase joints, fins, grabens above salt walls, and the highest concentration of arches in the world.
This CD contains geographic information system (GIS) files in ESRI file geodatabase and shapefile formats. A geologic map at 1:24,000 scale and a 31-page booklet are also included in PDF format. The latest version of Adobe Reader is required to view the PDF files.
Here are several more articles about the UGS rockfall investigation, including our own news release with links to the published report.
By: Charles G. Oviatt
This 20-page report summarizes observations of sediments and shorelines of the Gilbert episode in the Bonneville basin of northwestern Utah. Lake Bonneville dropped to altitudes similar to those of modern Great Salt Lake by 13,000 years ago, remained low for about 1400 years, then rapidly rose about 50 ft (15 m) during the Gilbert episode (about 11,600 years ago). The Gilbert lake was probably less extensive than shown by previous mapping of the Gilbert shoreline. The lake reached altitudes of 4250-4255 ft (1295-1297 m), and its shoreline, which is not well defined anywhere in the basin, was probably not deformed by residual isostatic rebound associated with removal of the Lake Bonneville water load. Holocene Great Salt Lake has not risen as high as the Gilbert-episode lake.
By: Tyler Knudsen, Paul Inkenbrandt, William Lund, Mike Lowe, and Steve Bowman
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.
Although this product represents the work of professional scientists, the Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, expressed or implied, regarding its suitability for a particular use. The Utah department of Natural Resources, Utah Geological Survey, shall not be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to claims by users of this product.
By: Tyler R. Knudsen
The Enoch quadrangle, in eastern Iron County, Utah, includes the northeastern part of Cedar Valley and parts of the adjacent Red Hills. The Red Hills-structurally consisting of an elevated, fault-bounded horst block-expose the upper parts of the Tertiary Claron Formation as well as a chaotic mass of Miocene and Oligocene volcanic rocks that may be part of the Markagunt Megabreccia that is widely exposed on the central and northern Markagunt Plateau to the east. Basaltic andesite flows cover large parts of the North Hills in the northeastern part of the quadrangle. Earth fissures related to groundwater overdraft of the Cedar Valley aquifer and resultant land subsidence have formed along parts of the eastern and western margins of the Enoch graben.
This CD contains two plates-a geologic map at 1:24,000 scale and an explanation plate-and a 12-page booklet, all in PDF Format. The latest version of Adobe Reader is required to view the PDF files.
By: Tyler R. Knudsen and Robert F. Biek
The Cedar City NW quadrangle includes the southwestern part of Cedar Valley and parts of the adjacent Eightmile Hills and Granite Mountain in Iron County, Utah. Exposed strata range from the Jurassic Temple Cap Formation to Oligocene-age quartz monzonite of the Granite Mountain laccolith. Emplacement of the Granite Mountain and Three Peaks laccoliths was controlled by the east-verging Sevier-age Iron Springs Gap thrust fault. Replacement manetite-hematite ore bodies in the Co-op Creek Limestone Member exist locally along the margins of the laccoliths and have made the Iron Springs mining district the largest iron-producing district in the western U.S. In the Eightmile Hills, regional ash-flow tuffs are locally involved in a large gravity slide shed off the Granite Mountain laccolith. Earth fissures related to groundwater overdraft of the Cedar Valley aquifer and resultant land subsidence have formed north and west of Quichapa Lake.
This CD contains two pates-a geologic map at 1:24,000 scale and an explanation plate-and a 18-page booklet, all in PDF format. The latest version of Adobe Reader is required to view the PDF files.
The Utah Geological Survey (UGS) is a division of the Utah Department of Natural Resources. Several specialized programs comprise the UGS: Data Management, Energy & Minerals, Geologic Hazards, Geologic Information & Outreach, Geologic Mapping, Groundwater & Wetlands, and Paleontology.
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