95% of the statues on Rapa Nui are made out of volcanic tuff. The statues are examples of monumental carving with 961 maoi at more than 210 sites. The moai are erected on ‘image’ ahu located along the coast. ‘Image’ ahu are monuments that have a platform, a ramp on the inland side leading to a leveled court and in most circumstances wing-like construction extended out laterally from one or both ends of the platform. The moai would be placed on a pedestal on the platform and would face inland. The ahu would have been the center of social and spiritual life for the community. The construction of ahus started as early as AD 1300 to 1400 and construction and remodeling would have gone on until the end of the 17th century. The 2003-2004 UNESCO-JAPON project at the site complex at the ahu Ura Uranga te Mahina. The goal of the research was to establish chronological patterns of use and discard at Ura Uranga, find more evidence on stone working methods and distinct stages of shaping and examine what the statues can tell us about statues uses and attached meanings. Based on the characteristics of the three Ahu at Ura Uranga it was determined that Ahu three was built first, then Ahu five and finally Ahu four. Ahu three shows the most damage of all three from tsunamis as well as being partially buried by the reconstruction of Ahu four. No statues intact or otherwise were found at Ahu three, which suggests that Ahu three may have been built before people in Rapa Nui started erecting statues.
Ahu five was built next. It supported at least four moai, there were parts of several moai found buried at the base of the Ahu and no intact statues were found. There was one moai found buried under the ramp resting on bedrock, suggesting that the statues at Ahu five were being decommissioned. Even though there were no intact statues two torsos were intact enough to give an approximate height of the statues between three and four m. Ahu four is the most recently built of the Ahus. It is located between Ahu three and five and was built partially on top of them and has the highest platform at 9.5 m.
Ahu four supported three large moai that are now lying face down with their bases resting on the platform and one of the statues is still intact. The heights of the statues of Ahu four were between 5.5 and 6.6 m. We know that over time the people on Rapa Nui started making the statues bigger over time. Ahu four has taller statues than Ahu five as well as a higher platform this coupled with the idea that the statues at Ahu five were being decommissioned tells us that Ahu four was built before Ahu five. Evidence demonstrating stone working methods and stages of shaping came from a statue found 46 m Northwest of Ahu 5. This statue was lying face down, semi buried and is intact. This statue was probably meant for Ahu five considering the distance it was found and the height of the statue was 3.25 m similar the other statues found at Ahu five. Excavation around the face showed the head features were finely carved and the face had a smooth surface but the eyes were unopened and the ears were unfinished. The body of the statue was also unfinished, the fingers were not yet carved and the base was proportionally larger than the other already erected statues. Because this statue was incomplete it suggests that it was most likely being transported to an Ahu and would have been finished when it was erected. The people on Rapa Nui probably were waiting to finish the statue when it was erected in case it was damaged in transport. The statues most likely represent the ancestors of important people in the community; chiefs and religious leaders. The increase in size of the statues may have come from the idea that ancestors could become deities and therefore the increase in size would the show the status and significance of the ancestor. The statues still had significance when they fell or were taken down. Many the fallen statues have evidence of being used in rituals. For example the unfinished statue that was left in the court was found with cobblestones, red scoria and coral pieces placed around the head and base. When the statue was excavated human and avian bones were found buried under the stomach. The burying of statues, like the one at ahu five that was buried under the ramp, with bones and red scoria may show a parallel between how humans were buried and how statues were buried i.e. burial at an ahu.