A geyser at Yellowstone National Park underwent a violent explosion on July 23, sending mud and debris into the air.
There were no reports of injuries, but an investigation into the incident is ongoing, and the extent of the damage is being assessed.
Biscuit Basin, including the parking lot and boardwalks, is temporarily closed for safety reasons. The Grand Loop Road remains open, according to the statement.
Hydrothermal explosions are common at Yellowstone Park, according to the U.S. Geological Survey (USGS) at the Yellowstone Observatory. Many of these explosions occur in the backcountry, where they go largely unnoticed, however.
The explosions are usually the result of water flashing into steam underground, according to the USGS.
“Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments. The explosions can reach heights of 2 km (1.2 miles) and leave craters that are from a few meters (tens of feet) up to more than 2 km (1.2 mi) in diameter,” according to the USGS.
The explosion might have been caused by an accumulation of minerals that clogged an underground pipe. Yellowstone is located atop a vast network of hydrothermal plumbing, filled with heated water and steam.
The previous explosion at Biscuit Basin was in May 2009.
Generally, these explosions are difficult to predict and can occur at any time, despite the presence of seismic sensors, according to the USGS.
The investigation by the Park Service and USGS aims to reveal whether any changes were caused by the explosion to the underground system.
Before it is determined whether the area can be reopened for visitors, measurements of chemical makeup and temperature will be obtained and tests on residual rumbling will be conducted by earthquake scientists.
“No other monitoring data show changes in the Yellowstone region,“ the NPS said in the statement. ”Today’s explosion does not reflect a change in the volcanic system, which remains at normal background levels of activity.”
The NPS stated that more details about the event will be made public as information becomes available.