The collapse of a famous arch in Utah raises the question of whether other famous arches are also at risk.

SALT LAKE CITY (AP) — A common set of questions has surfaced in the week since the collapse of an iconic rock arch at Lake Powell, known as the “Toilet bowl” collapsed.

Are these arches also in danger of collapsing soon? What are you doing to prevent such a collapse?

The answers: “Maybe” and “nothing,” said Karen Garthwait, spokeswoman for Arches and Canyonlands National Parks.

“Our mission is not to stop time and preserve these structures exactly as they are,” she said. “Our mission is to preserve the natural processes that create these structures, and that is, of course, the same process that will ultimately destroy them.”

When the geological formation officially named “Double Arch” collapsed last Thursday in Glen Canyon National Recreation Area, it was a sad reminder to many that arches don't last forever. All arches have a lifespan that scientists don't want to shorten – or extend.

Experts say human activity has accelerated erosion over the past hundred years, meaning the arches could collapse at any time. But it's difficult to predict exactly when they might collapse.

A bow's external appearance provides little indication of its strength. The sturdiest bows may have internal cracks, while others that appear to defy gravity stand up better to the elements.

According to the Utah Geological Survey, the sandstone rock in southern Utah is strong enough to support the weight of large arches – one of the most stable forms found in nature – but soft enough to be shaped over time by wind, water and gravity. The region's semi-arid climate also plays a major role in the formation and preservation of the sandstone wonders.

While the National Park Service does not physically reinforce the arches (a plan to cover one of them with plastic was abandoned in the 1940s), but has enacted strict guidelines to limit human impact on the natural structures.

Only two decades ago, park visitors could be seen walking on some of the arches and holding on to them for photos. A climber scaled Delicate Archthe most famous of Utah's more than 6,000 arches, left rope grooves in the sandstone that Garthwait said can still be seen today. The climb prompted park officials to rewrite regulations in 2006 to clarify that arch climbing is prohibited.

At Lake Powell, a large reservoir on the Utah-Arizona border, families often climbed the now-collapsed arch and jumped into a swimming hole below, even though cliff jumping is prohibited in the recreation area. Park rangers and geologists suspect that frequent foot traffic and fluctuating water levels contributed to the arch's collapse. The reservoir's water level was Decline due to drought and climate change since 2001, according to the National Park Service.

“Some people believe that rock is strong and unaffected by humans,” says Jeff Moore, a professor of geology and geophysics at the University of Utah. “When collapses like this happen, it reminds us how fragile rock arches are. Small changes can make a difference.”

Moore has led research projects that measure seismic activity beneath Utah's mountain arches and apply civil engineering principles to assess their structural health. The rock formations vibrate constantly, he said, and man-made energy sources such as trains, trucks and helicopters amplify those vibrations, stressing the mountain arches and accelerating crack growth.

The Federal Aviation Administration Last year, as a result of Moore's research, flight restrictions were imposed on helicopters flying near Rainbow Bridge National Monument in Utah – one of the largest known natural bridges in the world – to prevent vibration-related damage.

Humans have dramatically changed the vibrational landscape over the last century, he said, and as a result, more arches could soon collapse.

“That's a really rapid change in the lifespan of an arch,” Moore said. “Geology moves slowly. Humans have arrived quickly and are dramatically changing the environment in some places.”

A US Bureau of Reclamation facility in western Colorado that collects salt water from the The Colorado River system and injects it deep into the ground. It has also been linked to earthquakes near national parks in Utah. The site was temporarily closed after a magnitude 4.5 earthquake was recorded there in 2019, but has since resumed operations at a reduced rate.

For Richard Beckman, president of the Natural Arch and Bridge Society, it is an urgent concern to see the world's most famous arches before they are destroyed because he knows they could collapse in his lifetime.

“It's like losing an old friend,” Beckman said. “I'm sad to see them go, but I'm even more sad to see the arches collapse, which I never saw in person. We don't know how long they'll last, so you have to cherish them.”