JACKSON, Wyo. — Last month’s 5.0-magnitude earthquake near Jackson raised worries of another natural disaster and caused the West Broadway Landslide to lurch forward 1 millimeter.
Normally the slide moves half a millimeter each week.
Former Wyoming state geologist Wally Ulrich says that that had the quake occurred closer to town, or during a time of year with wetter conditions, the slide’s movement could have been far more substantial.
“The town needs to move forward and take care of stabilizing that zone,” Ulrich said, “because further earthquakes at different times and locations, or when it’s slightly more wet, could cause greater slope instability and create much larger problems.
“Conditions change,” he said. “We could have four or five days of rain saturate that area and have a quake like this that could cause the hillside to destabilize.”
With the world’s largest volcanic caldera in Yellowstone and hundreds of faults throughout the valley, Jackson Hole is fairly active geologically.
The Jackson Hole News and Guide (http://bit.ly/2bYOmRS ) that the town is in the process of completing designs to stabilize the portion of the landslide on town-owned property, but work is not expected to begin until next spring.
“Phase two of the mitigation work is slated to begin in mid-March, early April 2017,” Carl Pelletier, the town’s public information officer, wrote in a press release after the town was notified of the slide’s movement. “These operations will only mitigate the town’s public right of way and protect public infrastructure, including the town’s main water line, a sewage main line and West Broadway. It is projected that this stabilization project will be completed by December of 2017.”
In preparation of construction, the town of Jackson purchased the land above the slide, and the house that was located on the property was demolished.
Information from: Jackson Hole (Wyo.) News And Guide, http://www.jhnewsandguide.com