WSGS discusses Wyoming landslides, work, challenges and case studies
The U.S. Geological Survey (USGS) hosted Wyoming State Geological Survey (WSGS) Geologist James Mauch on Nov. 16, 2022 to cover past and ongoing work by the WSGS to map, characterize and assess the hazard of landslides within the state of Wyoming.
Additionally, he talked about some of the hurdles associated with this work and presented several case studies of prominent landslides in Wyoming.
Survey background
“WSGS is an independent state agency,” said Mauch. “Our mission is two pronged – we’re tasked with promoting the beneficial and responsible development of Wyoming’s mineral and energy resources, as well as understanding, characterizing and informing the public about geologic hazards.”
As a nonregulatory agency, WSGS primarily works to study and disseminate information about Wyoming’s geology for the benefit of Wyoming citizens, he noted.
The WSGS website shares, since 1933, WSGS has performed important and critical functions of interpreting Wyoming’s complex geology. WSGS scientists work to gain a better understanding of Earth’s history, geologic wonders, hazards and natural resources such as water, minerals and energy.
Additionally, scientists gather information, provide technical analyses, perform scientific investigations and generate maps using geographic information systems (GIS).
The team covers three core subject areas. They include energy and mineral resources; hazards, groundwater and GIS and administration, outreach and publications.
Projects background
One of WSGS’s projects is their statewide landslide inventory. From the late 1980s to the 2000s, Jim Case, WSGS geologic hazards division manager, led the project.
“This was an enormous event,” shared Mauch. “It was a statewide inventory and was completed through geologic mapping.”
WSGS’s geologic mapping program provides information on geologic structures and stratigraphy of a study area. WSGS geologists use a multi-disciplinary approach to geologic mapping, including remote sensing, structural geology, stratigraphy and geochronology to name a few.
Geologists and GIS specialists at WSGS use a variety of GIS software programs to publish digital geologic map products.
WSGS mapping is conducted at 1:100,000 and 1:24,000 scales. The agency is working toward mapping the entire state at the 1:100,000 scale. Areas of special interest are commonly mapped at 1:24,000.
Since 1994, WSGS has been an annual participant in the National Cooperative Geologic Mapping Program (NCGMP) – State Geologic Survey Mapping Component (STATEMAP).
2022 projects
Geologists at WSGS worked on a pair of 1:100,000-scale geologic maps through the STATEMAP managed by USGS.
Fiscal Year 2022 projects included a 1:100,000-scale surficial geologic map of the west half of the Ramshorn 30 feet by 60 feet quadrangle in Fremont and Park counties and a 1:100,000-scale bedrock geologic map of the Firehole Canyon 30 feet by 60 feet quadrangle in Sweetwater County, Daggett County, Utah and Moffat County, Colo.
The Ramshorn quadrangle encompasses portions of the northern Wind River Range, northwestern Wind River Basin and southern Absaroka Range. Generating data about landslides is one goal of the project.
The quadrangle is in one of the most landslide-prone regions in the state. U.S. Highway 26/287 runs through the quadrangle and has been damaged by unstable slopes in recent times. The project provides detailed mapping of glacial, alluvial and other surficial deposits contributing to understanding the regional quaternary geologic history.
The Firehole Canyon map compiles quadrangle’s bedrock geology. The map provides geologic data relevant to the economic resources within the southern Greater Green River Basin.
In addition, WSGS is looking to work on several other projects. They include three surficial maps of quads in central Wyoming for Riverton, Thermopolis and Carter Mountain quadrangles in Central Wyoming; an online map on mineral resources in the state under development; a pair of projects focusing on heavy-mineral sands and helium resources in Wyoming.
Mauch added another ongoing project will include updating their statewide landslide database with landslide mapping that’s informed by light detection and ranging data.
Challenges
“One of the unique factors in Wyoming is we have a very low population density and most of the population centers in the state are in the basins,” said Mauch. “There’s not a lot of intersection of where the landslides are and where people live, so, most of these landslides are occurring in remote mountainous areas in the western part of the state.”
He explained from a societal perspective, this is a great thing, but from a scientific perspective, it’s a challenge because it makes it difficult to study and track landslides. It also causes public awareness for landslide hazard to be fairly low in Wyoming.
“Another challenge we face, which is certainly not unique to Wyoming – it’s likely present in all Western states and throughout most of the country – is the fact that when landslides do occur in the front country, the assets typically damaged are transportation corridors and infrastructure,” said Mauch.
He noted in Wyoming, the Wind River Canyon is one transportation corridor particularly problematic when it comes to slope stability issues.
Another problematic area is the Togwotee Mountain Pass between Dubois and Moran.
Notable landslides
During his presentation, Mauch highlighted several notable landslides in Wyoming. He shared one of the most notable landslides occurred in 1925 – the Gros Ventre landslide – one of the largest, fast-moving landslides occurring near the town of Kelly.
The Crystal Creek landslide of 2007-12, Double Draw landslide of 2011 and Budge Drive landslide of 2014 were other notable landslides in the state.
“In Wyoming, we have a wide spectrum of landslide hazard and landslide severity,” said Mauch “And this is because within our state, we have diverse topography, geologic structures and climates that really control the landslide hazard.”
“In the immediate future, our work here is going to focus on producing some larger scale landslide susceptibility maps by county or 30 feet by 60 feet minute quadrangle,” he concluded.
He shared he is always eager to visit with folks who are tackling similar projects in other regions. He can be reached by e-mailing james.mauch@wyo.gov.
Brittany Gunn is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
