DENVER — A hidden landscape plagued by landslides is coming into focus in Yellowstone National Park, thanks to a laser-equipped aircraft.
Scientists of yesteryear toured Yellowstone on foot and studied aerial photographs to better understand America’s first national park. But today, researchers have a massive new digital dataset at their fingertips that is shedding new light on this nearly 1 million-hectare natural wonderland.
These Yellowstone observations have allowed a couple of researchers identify more than 1,000 landslides in and near the parkhundreds of which had not been mapped before, the duo reported Oct. 9 at the Geological Society of America Connects 2022 meeting. Most of these landslides likely occurred thousands of years ago, but some are still moving.
Mapping Yellowstone landslides is important because they can cripple infrastructure like roads and bridges. The millions of visitors who explore the park each year access Yellowstone through a handful of driveways, one of which recently closed for months after intense flooding.
In 2020, a small plane flew a few hundred meters over the otherworldly landscape of Yellowstone. But it wasn’t transporting tourists eager to see the sights of the park up close. famous wolves either hydrothermal vents (Serial Number: 7/21/20, Serial Number: 1/11/21). Instead, the plane carried a downward-pointing laser that fired pulses of infrared light at the ground. By timing the pulses that hit the ground and reflect back to the plane, the researchers reconstructed the precise topography of the landscape.
This “light detection and ranging” or lidar data reveals details that often remain hidden from view. “We can see the ground surface as if there is no vegetation,” says Kyra Bornong, a geoscientist at Idaho State University in Pocatello. Similar lidar observations have been used to identify pre-Columbian settlements deep in the Amazon rainforest (Serial number: 05/25/22).
Yellowstone lidar data was collected as part of the 3D elevation programan ongoing project spearheaded by the United States Geological Survey to map the entire United States using lidar.
Bornong and geomorphologist Ben Crosby analyzed Yellowstone data, which resolve details as small as one meter, to detect landslides. The team looked for places where the landscape changed from a relatively smooth look to a messy look, evidence that the soil and rocks were once in motion. “It’s a pattern recognition game,” says Crosby, also of Idaho State University. “You’re looking for this contrast between the lumpy stuff and the smooth stuff.”
The researchers detected more than 1,000 landslides in Yellowstone, most of which were clustered near the park’s periphery. That makes sense given the geography of Yellowstone’s interior, says Lyman Persico, a geomorphologist at Whitman College in Walla Walla, Washington, who was not involved in the research. The park sits on top of a supervolcanowhose previous eruptions covered much of the park with lava (Serial number: 2/1/18). “You’re sitting in the middle of the Yellowstone caldera, where everything is flat,” says Persico.
But rugged terrain also abounds in the national park, and there is infrastructure in many of those landslide-prone areas. In several places, the team found that roads had been built on debris from landslides. An example is Highway 191, which skirts the western edge of Yellowstone.
This highway is worth keeping an eye on, as it funnels significant amounts of traffic through regions prone to experiencing landslides, says Bornong. “It’s one of the busiest highways in Montana.”
There is much more to learn from this new look at Yellowstone, says Crosby. Lidar data can shed light on geological processes like volcanic and tectonic activity, both of which Yellowstone has in abundance. “It’s a transformative tool,” she says.