A catastrophic wave
On May 22, 1960, the most powerful earthquake ever recorded struck southern Chile. The magnitude 9.5 Valdivia earthquake generated a massive tsunami that radiated across the Pacific Ocean. On Easter Island (Rapa Nui), the wave struck the southeastern coast with devastating force. At Ahu Tongariki, the largest ceremonial platform on the island, the tsunami was catastrophic. Waves estimated at 10 meters (33 feet) high crashed ashore, sweeping over the monument. The force was immense enough to lift and scatter all 15 of the platform's moai—monolithic human figures carved from volcanic tuff. Statues weighing an average of 40 metric tons, with the largest an estimated 86 tons, were tossed hundreds of feet inland, leaving the sacred site in ruins.
The event completely destroyed the ahu, a stone platform nearly 220 meters (722 feet) long. The tsunami's power churned thousands of cubic meters of rock and debris, burying the site and erasing centuries of cultural history from view. For over 30 years, the largest and most impressive ceremonial center in all of Polynesia lay as a scattered field of stone giants.
The archaeological resurrection
In 1992, a major archaeological restoration began, led by Chilean archaeologist Claudio Cristino of the University of Chile. The ambitious five-year project was made possible through a collaboration with the Chilean government and significant financial and technical support from Japan. The Japanese crane company Tadano provided a large crane essential for lifting the multi-ton statues, which had to be shipped over 8,000 kilometers to the remote island.
The restoration process was a monumental task of forensic archaeology. Before re-erecting the moai, Cristino's team had to excavate and completely reconstruct the destroyed platform. This process yielded new information about its construction. The project revealed that the ahu was not a simple mound but a complex piece of engineering. Excavations uncovered that Rapanui builders had laid a deep foundation of tightly packed basalt boulders over a leveled clay surface. This design created a flexible, earthquake-resistant base capable of supporting the immense weight of the statues.
The team also discovered that the main axis of Ahu Tongariki has a precise astronomical alignment. It is oriented to face the rising sun during the summer solstice. By 1996, after years of meticulous work, all 15 moai were once again standing on their reconstructed platform, restoring the site.