While it was previously thought that Rapa Nui was several million years old, a recent study by Vezzolli & Acocella (2009) showed that extensive volcanism at the Easter Hotspot started some 800,000 years ago, giving birth to the three volcanoes that formed Rapa Nui (Poike, Rano Kau, and Terevaka). Thus, Rapa Nui is geologically very young, and it is assumed that Motu Motiro Hiva is a little bit older than Rapa Nui. To the east of Motu Motiro Hiva are many seamounts that were deposited by the Easter Hotspot on top of the Nazca Plate (Figure 2). At the moment of their formation, some of these seamounts where islands that reached above the sea surface, but as the Nazca Plate moved further eastwards, away from the Easter Hotspot, it cooled and the mountains were slowly sinking down. When they sank below the sea surface, these mountains became “seamounts”, forming the Easter Seamount Chain, which stretches from Rapa Nui almost 2000 km to the east. The oldest seamounts are the ones farthest to the east, and the youngest ones are the ones right above the Easter Hotspot, namely Rapa Nui and Motu Motiro Hiva (Figure 3). As the oceanic plate was formed before the islands and seamounts, these are typically younger than the surrounding plate (compare the age data in Figure 3).