DENVER — A hidden landscape riddled with landslides is coming into focus in Yellowstone National Park, thanks to a laser-equipped airplane.
Scientists of yore crisscrossed 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’s shedding new light on this nearly 1-million-hectare natural wonderland.
Two researchers have been able to observe Yellowstone from their respective perspectives. Find over 1,000 landslides near and within the parkThe duo presented their findings at the Geological Society of America Connects 2020 meeting on October 9. While most of these landslides probably occurred thousands of year ago, some of them are still moving.
Mapping Yellowstone’s landslides is important because they can cripple infrastructure like roadways and bridges. Only a few roads allow visitors to Yellowstone each year, which is why millions visit the park every year. One of these entrance roads was recently renovated. Following intense flooding, roads were closed for many months.
A small plane flew just a few hundred metres above Yellowstone’s extraordinary landscape in 2020. But it wasn’t ferrying tourists eager for up close views of the park’s Famous wolvesOder Hydrothermal vents (SN: 7/21/20, SN: 1/11/21). Instead, the plane had a downward-pointing light source that sent pulses of infrared radiation at the ground. Researchers were able reconstruct the topography of this landscape by measuring the timing and reflection of the infrared light that hit the ground.
Such “light detection and ranging,” or lidar, data reveal details that often remain hidden to the eye. “We’re able to see the surface of the ground as if there’s no vegetation,” says Kyra Bornong, a geoscientist at Idaho State University in Pocatello. Similar lidar observations have also been used for pinpointing. Pre-Columbian settlements deep in the Amazon jungle (SN: 5/25/22).
The data for the Yellowstone lidar were collected as part 3D Elevation ProgramThe United States Geological Survey has been leading the mapping of the whole country using lidar.
Bornong and geomorphologist Ben Crosby analyzed the Yellowstone data — which resolve details as small as about one meter — to home in on landslides. The team looked for areas where the landscape appeared to have changed from being relatively smooth to becoming jumbled. This was evidence that soils and rocks were once moving. “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.”
Yellowstone was home to more than 1,000 landslides, with most of them located around the park’s perimeter. That makes sense given the geography of Yellowstone’s interior, says Lyman Persico, a geomorphologist at Whitman College in Walla Walla, Wash., who was not involved in the research. The park Sits on top of a supervolcanoThis volcano, whose eruptions have previously lava covered much of the park (SN: 1/2/18). “You’re sitting in the middle of the Yellowstone caldera, where everything is flat,” says Persico.
But steep terrain also abounds in the national park, and there’s infrastructure in many of those landslide-prone areas. The team discovered that roads were built on top of landslide debris in several locations. Highway 191, which runs along the western border of Yellowstone, is one example.
It’s worth keeping an eye on this highway since it funnels significant amounts of traffic through regions apt to experience landslides, Bornong says. “It’s one of the busiest roads in Montana.”
There’s plenty more to learn from this novel look at Yellowstone, Crosby says. Lidar data can help shed light on geologic processes, such as volcanic and tectonic activities, which Yellowstone has abundantly. “It’s a transformative tool,” he says.
