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News Release:  Release of new Maricopa County Earth Fissure Map ( Download this Press Release)
Date:  01.12.2009

Release of New Maricopa County Earth Fissure Map

Download Maricopa Map

Rodgers Fissure of west-central Maricopa County circa 2007.

Reopening of Y-Crack fissure - 23 July 2007 - near Maricopa-Pinal County line.

CONTACT:  Michael Conway ( 520.209.4146;

Tucson.   Arizona Geological Survey (AZGS) geologists have completed mapping the earth fissures of Maricopa County.   They identified and mapped more than seven miles of fissures in 8 separate study areas that are compiled together on this new county-wide map.  The finished Maricopa County Earth Fissure Map (map scale 1:250,000) is available online as a PDF download at AZGS’s Earth Fissure Center

The map shows an additional 17-miles of previously reported fissures whose existence could not be confirmed because they are located in active farm fields or in rapidly urbanizing areas where the ground is disturbed and the fissure masked. 

The largest fissure in Maricopa County is the Rodgers fissure in the Harquahala Plain near the Maricopa-La Paz county line; it is nearly 1-mile long, up to 9-feet wide, and in several places more than 45-feet deep. “Owls have been spotted nesting in the fissure and on one occasion the carcass of a cow was discovered” said AZGS geologist Joe Cook, who heads the fissure map program. For Cook’s pictures of the Rodgers Fissure click here.

The historically prominent “Y crack” fissure, which crops out near Chandler Heights on the Maricopa – Pinal County border, is the most extensive fissure network in the county.   During monsoon rains in July 2007, the fissure reopened forming a crevasse 40-feet deep and 15-feet wide that damaged San Tan Blvd and Happy Road near 195th St, while engulfing and killing a horse in a corral.  The fissure network, which includes segments in both Maricopa and Pinal County, is about a mile in length. 

Besides posing a threat to infrastructure and livestock, fissures are a dumping ground for tires, appliances, construction debris, manure and other sundry items. Because the fissures are believed to extend down to the water table, earth fissures represent a potential threat to the groundwater that sustains growth in Maricopa County.

AZGS Contact Information

Michael Conway:
520.209.4146; 520.971.3688 cell;
Joe Cook:

Related Downloads

Maricopa County Earth Fissure Map (DM-EF-17)

Download this Press Release

Related links

AZGS Earth Fissure Center

Earth Fissure Viewer

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