A recent study revealed that the famous Zion National Park in Utah, USA, was formed as a result of an enormous landslide that significantly altered the topography of the area, and still continues to do so.
The study, conducted by a team of scientists at the University of Utah, was reported in the June 2016 issue of GSA Today, the journal published by the Geological Society of America. According to the study, the landslide that transformed the canyon consisted 286 million cubic meters of rocks that came rushing down from the neighboring Sentinel Mountain around 4,800 years ago.
In a University of Utah news release, the lead author of the study and Assistant Professor of Geology and Geophysics at the University, Jeff Moore, stated that the rocks from the avalanche moved at an average speed of 112 meters per hour, and it had taken only a minute for the devastation to occur.
According to GSA Today, the debris blocked the path of the Virgin River that flows through the National Park, creating a dam and, consequently, a lake. The Sentinel Lake is estimated to have been spread over approximately 2.4 square kilometers in what is now the valley floor of Zion canyon. It was stable for around 700 years, after which it was overrun by the sediments accumulated in it by the Virgin River. The former site of the lake is now smooth and flat, a major attraction to tourists at the Zion National Park.
According to the University news report, Moore calculated that the river has eroded away almost half of the debris deposited by the landslide 4,800 years ago. He speculated that if this continued, then in another several thousand years, the area would revert again to being a steep, narrow and rocky canyon. He went on to describe the rock avalanche as a minute with up to 10,000 years of consequences.