Impacts on People, Property, and Infrastructure

Geoscience at Work for Arizona – Landslide Database

In 2014, on the heels of deadly landslides in Washington and Colorado, the AZGS initiated its first landslide hazard program. Working hand-in-hand with the Arizona Division of Emergency and Military Affairs (DEMA), we landed a grant of ~$170,000 from the Federal Emergency Management Agency (FEMA) Pre-Disaster Mitigation program to build Arizona’s first statewide landslide inventory database (AzSLID) documenting historic, Holocene and Pleistocene landslide events.

Why AzSLID? A 250-foot section of US 89 near Page, Arizona, was swept away by a landslide in Feb. 2013. No one was killed or injured, but Page, principally accessible via US 89 saw its tourism industry sink beneath the waves of nearby Lake Powell. Two years later in March 2015, US 89 was returned to service – at a cost approaching $50+ million.

AzSLID provides county, tribal, and city planners, land management agencies, and the emergency management community with a powerful tool for reconnoitering existing landslide features with an eye towards managing development to mitigate the impact of landslide-prone slopes on the people, property and infrastructure of Arizona. AzSLID could well save lives and millions of dollars in damaged or destroyed buildings and infrastructure.

Building AzSLID. From 2014 to 2017, AZGS’ Ann Youberg and Joe Cook combed through geologic maps, reports, dissertations and theses to identify all previously documented landslides. At the same, we examined aerial photographs and imagery served by Google Earth to reconnssainase mountain slopes, canyons, and the perimeters of plateaus, mesas and buttes to explore for heretofore undiscovered landslide features.

Parameters of each landslide feature – landslide type, location, footprint, age, volume, and notes among other things – were compiled in the AzSLID database, which now includes more than 6,300 landslide features and 1,400 debris flow points. The database and a graphical representation of the entire data suite are available at the Natural Hazards in Arizona Viewer.