Earth

Mapping landslide risk across Indiana

The Indiana Geological and Water Survey conducts landslide risk assessments and creates landslide inventories across southcentral Indiana according to the schedule shown in the map above. The points represent the locations of previously recorded landslides. Work that began in 2023 targeted Hoosier National Forest properties (the darkest shade of gray). Construction began in 2024 and covered all of Bedford, Jasper, and Tell City. Credit: Casey Jones, Indiana Geological and Water Survey.

The Indiana Geological and Water Survey at Indiana University has published important research addressing landslide risk across the Hoosier State. New high-resolution imagery and digital elevation measurements being collected by the Indiana Geographical Information Service will help in this effort.

States with more rugged terrain than Indiana, such as Washington, Oregon and Kentucky, have long used light detection and ranging, said Victoria Leffel, the project’s principal investigator at the Indiana Geological and Water Survey. In other words, they have been using lidar to create maps of landslides.

The release of the Indiana Statewide LIDAR Image Set in 2020 marked a turning point for the state. The data was collected over four years and at a more detailed scale than previous sets released in the early 2010s, allowing researchers to develop three-dimensional models that more clearly reveal landslide sites. It’s done. A new third dataset, collected at even higher resolution over the next three years, will add even more depth to the data.

“We may be able to see potential landslide movement over time, which is very interesting,” Leffel said.

Since joining the study in 2022, Leffel has been working on using this LIDAR data to create Indiana’s first statewide landslide hazard map. Her previous research is outlined in the reports “Indiana Highway Landslide Hazards – Landslide Inventory Construction and Analysis” and “Landslide Hazard Mapping and Inventory in the Hoosier National Forest Using LiDAR Data” Published in the Indiana Journal of Earth. Science. Further research from her will be published over the next two years.

Lidar uses laser scanners and GPS to measure distance by sending short pulses of light to the ground. The data is used to create a 3D model of the surface. Geological mappers, hydrologists, and other scientists can use LIDAR and associated data to track changes over time along coastlines and riverbanks. In an abandoned mine. Or they may be caused by natural disasters such as karst (caves and sinkholes), landslides, volcanoes, and earthquakes.

Although Indiana has a lower risk of landslides and rockfalls than other parts of the country, some parts of the state are more susceptible than others due to topography, precipitation, and underlying geology. is. Southern Indiana includes several of these high-risk areas.

In February 2024, Leffel was called to Clifty Falls State Park in Madison after a 7- to 8-foot-tall chunk of limestone fell near a popular trail and tunnel. The Indiana Department of Natural Resources kept the tunnel closed after a report provided by Leffel warned of the risk of further rockfall due to weathering of the underground shale.

In late spring, while looking first-hand at what they were seeing on Lidar, Leffel and his field team discovered dozens of areas where landslides had occurred on public forest land in southern Indiana, including some near trails and dams. encountered.

Leffel’s original research showed that bedrock geology and lack of glaciers are closely related to landslide occurrence, with shale bedrock, changing topography, and groundwater fluctuations contributing primarily to landslide development and incidence. It was concluded that

Understanding the factors that lead to landslide risk can help builders, public emergency managers, and residents make better informed decisions.

“It’s difficult,” Leffel said. “The New Albany Shale is less susceptible to landslides, but the Cope Formation is more susceptible to landslides, so we can’t say ‘you can’t build on shale.’ Understanding how it works is an important consideration in road construction.”

Her current project, funded by a $45,439 grant, focuses on discovering and mapping landslide risk in a 15-county, 4,200-square-mile region of southeast central Indiana. I’m guessing. In addition to the regional landslide inventory, one of the expected outcomes this fall is to create landslide maps for state parks in these counties to aid in land management and education assistance.

An additional grant application currently under consideration would fund the creation of a comprehensive, publicly accessible landslide inventory for southcentral Indiana, covering portions of 13 counties. That inventory will incorporate not only LIDAR data, but also records related to Indiana’s transportation infrastructure dating back to the 1940s and Indiana Geological and Water Survey data from past bedrock mapping projects.

“Although the proposed project boundaries and future project boundaries are subject to change, our current goal is to ultimately be south of the Wisconsin Glacier Boundary and close to Interstate 70. “Mapping the landslide risk across the state roughly south of Highway 74,” Leffel said.

“Landslides in Indiana involve more than simple erosion, they involve large-scale soil and rock movement,” she says. “Although most events are slow-moving and do not have the dramatic impact of the rapidly progressing landslides often seen in news stories, these gradual events still pose significant maintenance challenges. Masu.”

Further information: Victoria Leffel, “Indiana Highway Landslide Hazard—Landslide Inventory Construction and Analysis,” Indiana Earth Science Journal (2024). DOI: 10.14434/ijes.v6i1.35484

Victoria Leffel et al, Hoosier National Forest Landslide Hazard Mapping and Inventory Using LiDAR Data, Indiana Earth Science Journal (2024). DOI: 10.14434/ijes.v6i1.39997

Provided by Indiana University

Citation: Mapping landslide hazards across Indiana (January 13, 2025), retrieved January 13, 2025, from https://phys.org/news/2025-01-landslide-hazards-indiana.html

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