Salt Lake City(ABC4) – this Utah Geological Survey (UGS) has completed a project to create new high-resolution maps of active faults throughout central Utah, a geologically critical area that geologists say will provide a clearer picture of the state’s earthquake risk.
According to UGS, previous fault mapping focused on the Wasatch Front. The new project focuses on central Utah, an area described by UGS as “the geologically critical transition zone between the actively extending Basin and Range Province and the stable Colorado Plateau.”
The study covered parts of Garfield, Juab, Millard, Piute, Sanpete and Sevier counties. Additionally, experts say the region is undergoing a transformation as its population grows and infrastructure develops.
This map shows the study area in central Utah, with red lines indicating new fault maps in this study. (Courtesy Utah Geological Survey)
“The region is home to growing communities, vital infrastructure and major transportation routes,” UGS said in a release. “The region has historically experienced strong earthquakes, including the two largest earthquakes in Utah history: the 1901 M6.6 Tushar Mountain Earthquake and the 1921 M6.0 Elsinore Earthquake, both of which caused widespread damage in the Sevier Valley.”
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In its new project, UGS reportedly used federal funds from the U.S. Geological Survey’s Earthquake Hazards Program to remap active faults. They studied faults that have fractured the Earth’s surface over the past 2.6 million years and can produce powerful earthquakes.
UGS said early mapping of these faults relied primarily on aerial photographs and field surveys and lacked “subtle or erosive fault scarps,” the step-like features that large earthquakes create on the landscape. Previous drawings become more difficult when these features are hidden by dense vegetation.
To better map the area, geologists used lidar (light detection and ranging) data to “significantly update the mapping and understanding of these faults,” UGS said. LiDAR reportedly enables geologists to digitally “see” through vegetation, exposing the earth below and revealing small or complex fault scarps that were previously difficult to detect.
“Lidar data is a game-changer in geomorphology and fault mapping because we are able to map features on the Earth’s surface, such as active faults, in greater detail than ever before,” said UGS project geologist Adam Hiscock.
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Using the new maps, geologists will be able to pinpoint areas where detailed, site-specific surveys should be conducted before any new development in the area.
Courtesy: Utah Geohazard Portal
“UGS created these maps to provide critical guidance for the development of safe and smart communities,” the release states. “UGS’s mission is to help our local governments, cities, towns and planning commissions understand the risks beneath their feet as they imagine future development. Local authorities play a vital role in incorporating UGS’s scientific data into public safety and planning policies.”
UGS outlines the following uses for the new mapping:
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Informed planning: Planning boards can use special study areas to direct new development away from high-risk areas, thereby protecting new homes, schools, hospitals, and infrastructure such as water lines and highways.
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Risk Mitigation: By making development decisions based on the most accurate data available, cities and counties can reduce future risks to life and property, ensuring a safer future for all Utahns.
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Guidance to local officials: Special Study Areas are advisory areas where UGS recommends that detailed, site-specific surveys be conducted by a qualified geologist before any new development.
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Enforcement of regulations: Local officials can use these maps to develop and enforce geohazard ordinances and ensure that buildings are not built directly on or too close to known traces of active faults.
You can access all data for this UGS project here. These resources can help homeowners, developers and local officials make informed decisions with the latest information.
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