This white paper has been created by Arizona Land Subsidence Group to help educate stakeholders and decision makers by describing the geological features and processes of land subsidence and earth fissures, and the hazards they create. This paper presents the current and future technical needs that exist in terms of basic knowledge, available data, and the state of professional practice.

In 2006, Arizona enacted legislation that directed the Arizona Geological Survey (AZGS) to map earth fissures in the state, required that the presence of earth fissures be disclosed in real estate transactions, and that the resultant earth fissure maps be made publicly available. In order to meet these statutory requirements, AZGS developed, for the first time, standards, procedures, and criteria for identifying, mapping, and characterizing earth fissures.

AZGS geologists identified earth fissures through a review of publications and reports, air photo analysis, and field reconnaissance. Using GPS, we collected relatively high-precision locations and descriptive data along the length of earth fissure surface exposures, and categorized them as either continuous or discontinuous. If we were not able to find and map previously reported fissures, we used the “reported, unconfirmed” category.