Earthquake Damage Threatens Multiple Caves At Craters Of The Moon National Monument

Sep 7, 2020

The coronavirus pandemic has forced challenges and changes to almost every public-facing entity, including national parks. At Craters of the Moon National Park, tours of the lava caves were stopped in March. But another natural disaster may keep the caves closed even longer.

The beginning of the pandemic was tough enough. Craters of the Moon National Monument stopped tours and closed its lava caves this summer due to staffing and social distancing challenges.

“We decided to constrict our operations and focus on other aspects to enable as much access overall to the park,” said Wade Vagias, superintendent of three national parks in southern Idaho, including Craters of the Moon.

Then came the 6.2 earthquake on March 31.

“We became concerned at that point about the structural stability of the caves,” Vagias said.

Pre- March 31, 2020 earthquake collapses in the high ceilings of Indian Tunnel give this picturesque cave an open and bright appearance.
Credit Craters of the Moon National Monument/National Parks Service

Two forest service cave experts found notable structural concerns in two park caves: Indian Tunnel, with its wide shape and thin roof, and sections of Boyscout Cave.

“The report also identified that there are some areas of loose rock and potentially active rock fall,” Vagias said. “There was one fracture in particular that has, [and] this is a direct quote, the potential to collapse.”

Later this fall Eric Bilderback, a parks service geomorphologist, plans additional evaluations to better understand new risks in the caves caused by recent seismic activity.

“We've done that in Zion and Grand Teton, and Hawaii volcano,” he said, referring to other National Parks. “We put some instrumentation on fractures or cracks in rock to see if there's any movement going on to get a much better idea about the behavior of those features.”

Bilderback says the process is about understanding and then communicating those risks to the public, while balancing the ability to let nature run its course.

Vagias remains optimistic that, given the proper time to evaluate, the caves in Craters of the Moon will again be open to the public.

“[The] National Park Service takes very seriously our cultural and natural resource stewardship responsibilities, as well as balancing those with visitor access,” Vagias said. “I think there's going to be some great conversations ahead of us as we seek to continue to provide as much access as we can in as safe a manner as possible.”

There’s no clear timetable for what’s next. Once it begins, the evaluation process of those caves could take more than a year. Bilderback said a similar evaluation in Kilauea’s lava tube caves took 18 months — but that area is obviously different than Idaho, and visitors here are less likely to show up in flip-flops and T-shirts.

“When you actually start looking at some of these natural things like rockfall or landslides from a risk perspective, it turns out that, societally we have higher risk tolerance for things like driving,” he said.

“And obviously, the last thing we want is anybody to get hurt. But we are talking about natural processes here. And it's not necessarily our job to change those natural processes.”

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