Protecting stone heritage in the painted desert: Employing the rock art stability index in the petrified forest national park, Arizona

Located in northeastern Arizona (USA), Petrified Forest National Park (PEFO) presents a unique story of both geologic and human history. Though perhaps most well-known for its abundant petrified wood and being part of the Painted Desert, visitors are often surprised when they discover PEFO hosts many ancient petroglyph sites. Over the years, many attempts have been made to record the petroglyph sites, but nothing has been done to assess their geomorphic stability. To address this shortcoming, we employed the Rock Art Stability Index (RASI) to assess geologic stability and (potential) deterioration of rock art sites in PEFO. Used for more than a decade as a triage for researchers assessing which rock art panels/sites are in the most danger of eroding, RASI uses a rank-based system to assess over three-dozen rock decay parameters, resulting in an overall condition analysis of a rock art panel. The findings can then be grouped together by site location to gain a clearer understanding of overall decay processes responsible for (potential) erosion. This study highlights RASI, its use as a low-cost, non-invasive, rapid field assessment technique, and assesses the geomorphic stability of five major petroglyph sites in the Petrified Forest National Park.