The primary use of the term Oceania is to describe a continental region (like Europe or Africa) that lies between Asia and the Americas, with Australia as the major land mass. The name Oceania is used, rather than Australasia, because unlike the other continental groupings, it is the ocean rather than the continent that links the nations together. Oceania is the smallest continental grouping in land area and the second smallest, after Antarctica, in population.
It consists of 607 islands extending 1,800 miles across the archipelago of the Caroline Islands. The four constituent island groups are Yap, Chuuk (called Truk until January 1990), Pohnpei (called Ponape until November 1984), and Kosrae. The population is 135,869 (2000) and the capital is Palikir, on Pohnpei.
Lōʻihi began forming around 400,000 years ago and is expected to begin emerging above sea level about 10,000–100,000 years from now. At its summit, Lōʻihi Seamount stands more than 3,000 m (10,000 ft) above the seafloor, making it taller than Mount St. Helens was before its catastrophic 1980 eruption. The summit is currently 975 m (3,000 ft) below sea level. A diverse microbial community resides around Lōʻihi's many hydrothermal vents.