 Vandalized petroglyphs from Willow Springs, Arizona |
 Panel undermined by fluvial undercutting, Gravevine Canyon, California |
Rock art site - pictographs (or cave paintings) and petroglyphs (rock engravings) - were created by Native American peoples to document their religious beliefs and practices, thereby expressing their artistic talents and interests. Rock art sites thus represent an unusual spiritual and creative record that contributes to our worldwide human heritage. Indeed, many of our US rock art sites represent aesthetic achievements that rival those created by other traditional, non-western peoples worldwide, and even the masterpieces of western European art. Yet Native American rock art sites are also intrinsically fragile and they are threatened, in many cases seriously and imminently, by natural processes and human activities. One rainstorm, or one carelessly positioned campfire, potentially could destroy a masterpiece of Native American art in a just few minutes; a masterpiece that had existed for thousands of years previously, in a near pristine form.
Although rock art sites are not common in any given region, the total number of sites in the wide expanse of our western states is somewhere in the tens of thousands. Yet only a handful of these sites have been examined to determine their condition and potential long-term stability (or lack thereof). While archaeologists know where thousands of rock art sites are located, and they have some idea of the kinds of the art that is present at many of these sites, they have no real knowledge about, let alone a systematic tabulation of, the condition of these sites, and any immediate threats that may confront them. Compounding these problems is another: funds and resources available to preserve and protect these sites are very limited, and difficult to acquire.
The result is an almost impossible circumstance: we know that our rock art sites represent part of the religious heritage of our Native American forebears, and we know that many of these sites include masterpieces of art that are world class in their significance. We also know that these sites are fragile and endangered. Yet we do not know which sites are most imperiled and, having limited resources to conserve these sites, we do not how best to allocate our efforts to maximum effect.
RASI - the Rock Art Stability Index - is a tool that allows for the rapid assessment of the condition of a rock art site. It has been designed for use by college students and archaeologists, and only requires a minimum amount of training to conduct. Its purpose is to provide a replicable system to rank order various aspects of the observable physical condition of rock art sites, and to thereby score a site in terms of its current vulnerability. By integrating RASI results for individual sites in a GISciences data base, it will be possible to determine which sites are in greatest danger in a region or a state. It will enable us to establish rational priorities for site management and more detailed conservation and preservation projects.
RASI in this sense is not intended as a method for conserving individual rock art sites. Site-specific conservation efforts require much more detailed efforts by highly trained experts. RASI instead is a mechanism for identifying and ultimately targeting existing preservation and conservation problems, and determining which are most pressing. It is in this sense an intermediate step that promotes logical planning intended to sustain this important aspect of our global cultural heritage.
After a short (2 day) training session in RASI, individual evaluators are capable of identifying and judging the severity of the physical conditions at a site, aided by the use of a color illustrated condition guide. Issues related to physical condition involve five primary analytical categories: (1) Fundamental weaknesses in the bedrock supporting a rock art site that facilitate erosion; (2) Aspects of the support rock that can result in rock art panel detachment; (3) Incremental erosion; (4) Loss of large blocks of a rock panel; and (5) Natural rock coatings and other deposits that either stabilize or promote instability. A final and flexible sixth category is also incorporated into the index. This allows for the inclusion of region specific concerns (such as human vandalism), and the differential weighting of this or any of the other categories in the calculation of an individual index score for a site. Testing conducted on the groups of trained college students demonstrates that the results for any given site are replicable between evaluators.
RASI will not fix all of the problems that our rock art heritage currently confronts. But it does provide us with a means for attacking these problems in a coordinated and efficient fashion. It is the first logical step in the important task of saving our rock art resources for future generations.