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Arizona Geological Survey assessing landslide sites

Staff ~ 4/1/2015

NORTH VALLEY –   Over the past decade, landslides in Arizona have damaged roadways and buildings, costing millions of dollars in repairs and adjustments.

In February 2013, a landslide along the Echo Cliffs south of Page sliced through several hundred feet of US Route 89. No one was injured, but the Arizona Dept. of Transportation closed the 23-mile section of road between Bitter Springs and Page. Two years and $25 million in repairs later, the highway has just reopened.

The Arizona Geological Survey is beginning a two-year project to inventory landslide sites throughout Arizona. According to AZGS research geologist, Dr. Ann Youberg, the project manager, “Our current understanding of the nature and extent of landslide activity in Arizona is rudimentary, and thus it is very difficult to assess the hazards associated with landslides.”

As part of this program, AZGS will inventory historic and prehistoric landslides, focusing initially on highly populated areas and transportation corridors where hazards and risks are greatest. But landslide hazards are on the increase as development expands into mountainous terrain and as record wildfires and monsoon rains fuel dangerous, fast moving debris flows, a type of landslide activity.

The Arizona Department of Emergency and Military Affairs is awarding $150,656 through the federal Pre-Disaster Mitigation program, to the AZGS to start compiling data on landslides, while AZGS provides a $50,219 match of non-federal funds.

“The landslide database will be a useful tool for emergency managers throughout the state,” said Wendy Smith-Reeve, DEMA Deputy Director. “By understanding which communities are at risk, we can take steps to mitigate the threat.”

This program will create an online interactive Arizona Statewide Landslide Inventory Database (AzSLID) of known and newly identified landslides, and an outreach and education program to inform local, tribal, county, state and federal stakeholders and the general public regarding the distribution, nature, and scope of landslides and landslide hazards in Arizona. 

According to Phil Pearthree, Chief of the Environmental Geology section of the AZGS, “For the first time, AZGS will begin to systematically assess the distribution of landslides in Arizona. With this catalog in hand, we will be able to identify existing and potential landslides that may impact infrastructure and pose a threat/risk to people and property.”

The data will be available in a variety of formats, including GIS formats, and freely accessible to land management authorities, policy makers and the public, online at the interactive Natural Hazards in Arizona site. 

Inventorying landslides and developing hazard and risk map assessments now will make Arizonans, their property, and infrastructure safer in the years ahead.