What are Earth Fissures?
Earth fissures are associated with basin subsidence that accompanies extensive ground water mining. In Arizona, fissures were first noted near Eloy in 1929. Their physical appearance varies greatly, but they may be more than a mile in length, up to 15 ft wide, and 100s of feet deep. During torrential rains they erode rapidly presenting a substantial hazard to people and infrastructure. Moreover, fissures provide a ready conduit to deliver runoff and contaminated waters to basin aquifers. Rapid population growth in southern Arizona is increasingly juxtaposing population centers and fissures.
AZGS Maps Earth Fissures
In August 2005, torrential monsoon rains reactivated an earth fissure near Queen Creek, Pinal County, Arizona. Within days the fissure became an open crevasse 10s of feet in length, 5 to 10 ft wide, and up to 25 ft deep. In response to growing public outcry, the Arizona Legislature drafted legislation that Governor Napolitano signed in to law to address earth fissures in Arizona. Effective September 21, 2006, Ariz. Rev. Stat. § 27-152.01(3) charges the Arizona Geological Survey (AZGS) with 1) comprehensive mapping of earth fissures throughout Arizona, and 2) delivering earth fissure map data to the State Land Department to be posted online with other GIS map layers for the public to use to build their own customized maps.
The maps and report included on this page are a compilation of previously or reported earth fissures in Cochise, Maricopa, Pima, and Pinal counties. On these maps we identify 23 discrete study areas hosting one or more earth fissures. For a list of our mapping priorities, please see AZGS Open File Report 07-01.
The AZGS mapping team is currently mapping earth fissures using high resolution meter to sub-meter GPS (global positioning system) receivers. These data will be displayed at 1:12,000 scale on the State's internet map server.
For further information: Please refer to the included earth fissure planning maps for the four counties, OFR-07-01 “Earth Fissure Mapping Program: 2006 Progress Report”, or contact us at 520.770.3500.