Earth fissures are long, narrow cracks in the ground that form where the ground is sinking. They can erode very quickly, posing a hazard to nearby infrastructure. In Arizona, land subsidence–the sinking of the earth–is caused by groundwater withdrawal, meaning that earth fissures are a man-made–or anthropogenic–hazard.
This video that I made as part of the Geological Society of America Science Communication Internships explains what earth fissures are, how they form, and the hazards that they pose.
Emily Zawacki, Ph.D. 