To the left: Pinal County earth fissure southern tract as it appeared on 19 January 2017. Note the steep sidewalls and variable fissure width that ranges from ~10 feet to less than one foot. Just beyond the drone, the fissure necks down into a deep V-shaped geometry characteristic of young or active earth fissures. The fissure bottom is an uneven and irregular surface that includes a large collapse block, lower center, evincing early sidewall collapse. Brian Gootee (AZGS) is the drone operator. (Photo by B. Conway of the Arizona Dept. of Water Resources.)
To the right: The same section of fissure as it appeared on 9 January 2019. The ground adjacent to the right sidewall shows fissure-parallel fractures and unstable blocks of earth. (Photo by Joe Cook).
Arizona Geology Blog post (27 Jan. 2019). http://blog.azgs.arizona.edu/blog/2019-01/rapid-infilling-fresh-earth-fi...
Cook, J.P., 2017, Discovery of a large earth fissure in the Southern Picacho Basin, Pinal County, Arizona. Arizona Geological Survey Open-File Report, OFR-17- 01, 7 p., 1 appendix.