AIC's 44th Annual Meeting

The Maya site of Copan is Honduras’s only cultural heritage site protected by UNESCO. Its Acropolis exemplifies some of the most magnificent constructions of the Classic Maya civilization, consisting of several joined courtyards and temples, and featuring the Hieroglyphic Stairway, the longest hieroglyphic text in the New World. Four kilometers of excavation tunnels beneath the Acropolis have confirmed that the construction of this monument took place over 400 years, encompassing the reigns of 16 named Maya kings. The architecture in the tunnels contains original sculptured, plastered, and painted surfaces that represent the dynastic monuments of the earliest rulers of Copan.   The vast majority of the tunnels remain unfilled, despite the fact that their investigation has been concluded. Some have been made available for tourism, and the Honduran Institute of Anthropology seeks to open more, but many are no longer in use and threaten the integrity of the Acropolis should they collapse. In 1997, Hurricane Mitch brought record-breaking rains through the mountainous regions of Honduras, swelling the Copan River nearby and causing water levels to rise up to 73 centimeters in the lowest tunnel levels. The uppermost, final phase East Court, the raised courtyard on the eastern side of the Acropolis, became a watershed with its recently installed waterproof membrane. The concentrated runoff from this membrane caused a four-meter-wide crack to open along the eastern cut of the Acropolis. Following Mitch, minor tunnel collapses occurred in areas associated with runoff patterns from the East Court as well.   Copan’s current Site Management plan advises against tunnel backfill. It does not include plans for disaster preparation or outline explicit conservation policies. The site also lacks a comprehensive three-dimensional map of the entire tunnel system. As the Honduran Institute of Anthropology queues up more tunnels to be opened to tourists, it becomes necessary to consider the pending risks as erratic weather patterns continue. Heavy rains and flooding along the alluvial fan of the Copan River Valley could cause further collapse and shifting throughout the Acropolis. The site is also located near an active seismic fault.   This fall, a small team will construct a digital three-dimensional model of the tunnel system in order to triage the areas that are the most at risk of collapse, to quantify the areas still in need of stabilization, and to determine the effectiveness of the waterproof membrane below the East Court.  This paper will investigate solutions such as backfill and stabilization methods to prepare for future storms or earthquakes, and methods such as air extraction devices and alternative barrier systems as potential mitigations for tourism. It will discuss the importance of monitoring to establish environmental control parameters for cave-like systems, and the difficulties of using data loggers in high-humidity environments. Finally, studying the conditions present in areas currently open to tourists will inform whether a decision to continue opening new tunnels to tourists is, in fact, wise—or whether it is just one more disaster to brace against.