Easter Island is famous for its giant monumental statues, called moai, built around 800 years ago. The volcanic rock used for the moai came from a quarry called Rano Raraku. Archaeologists created a high-resolution interactive 3D model of the quarry site to learn more about the processes used to create the moai. (You can explore the full interactive model here.) According to a paper published in the journal PLoS ONE, the model shows that there were many independent groups, likely family clans, that created the moai, rather than a centralized management system.
“You can see things that you couldn’t actually see on the ground. You can see peaks and sides and all kinds of areas that would be impossible to get to on foot,” said co-author Carl Lipo of Binghamton University. “We can say, ‘Here, go see.’ If you want to see the different types of sculptures, fly around and see things there. We’re documenting something that really needed to be documented, but in a really comprehensive and shareable way.
Lipo is one of Easter Island’s foremost moai experts. In October, we reported Lipo’s experimental confirmation – based on 3D physics modeling and new field tests to recreate this movement – that Easter Island residents transported the statues in an upright position, with workers using ropes to essentially “walk” the moai onto their platforms. To explain the presence of so many moai, it has been assumed that the island was once home to tens of thousands of people..
Lipo’s latest field trials have shown that the “walking” method can be achieved with far fewer workers: 18 people, four on each side rope and 10 on a back rope, to achieve the side-stepping movement. They were efficient enough to coordinate their efforts to move the statue 100 meters in just 40 minutes. In fact, the method works on the base dynamics of the pendulum, which minimizes the friction between the base and the ground. It is also a technique that exploits the gradual build-up of amplitude, suggesting a sophisticated understanding of the principles of resonance.
