Dominated by the fluid lavas of Hawaii, this region leads the world in eruptions producing lava flows, lava lakes, and radial fissure eruptions (in percentages of both its own total eruptions and those of each characteristic). The region is unusually homogeneous in its products, with virtually all eruptions consisting of basalt, from hotspot (Hawaii, Tahiti, Macdonald, Easter), ocean ridge crest, or fracture zone settings.
Only Regions 02, 03, and 19 have produced fewer large explosive eruptions (VEI >= 4). This region has the highest proportion of both shields (33) and submarine volcanoes (58), and these would be higher if island groups like the Galapagos and Revillagigedos had been placed here rather than with their nearest mainland neighbors in the Catalog of Active Volcanoes of the World. Because of the careful work on Hawaiian eruptive pre-histories, this region has the second highest number of eruptions dated by radiocarbon: 113, or 43% of its total eruption dates.
Region 13 was designated simply "Hawaii" upon publication of the 1955 Catalog of Active Volcanoes of the World (third in the 22-volume series and—at nine pages per volcano—the most detailed). It later became clear that there was Holocene activity elsewhere in the Pacific and, in keeping with the original Catalog of Active Volcanoes of the World designations for both Atlantic and Indian oceans, GVP expanded this region to cover the full ocean basin not already covered by other catalogs (e.g. Galapagos, Chilean, and Mexican islands). The result is the largest region, but the smallest total land area.
Easter Island was first discovered in 1722, and Tahiti in 1767, 11 years before Captain Cook first sighted Hawaii, the most visibly volcanic part of the region. American missionaries arrived in Honolulu in 1820, and the Wilkes Expedition, with 27-yr-old J.D. Dana, arrived in Hawaii in 1840. In 1874, US troops landed in the islands, and in 1893 the Kingdom of Hawaii was overthrown by US Marines. Hawaii was annexed in 1898, ceded itself to the US as the Republic of Hawaii two years later, and became the 50th US state in 1959. In 1911, American volcanologists Perret & Shepherd reached Kilauea, starting the first continuous monitoring, and the Hawaii Volcano Observatory (HVO) was founded in the next year.
In 1925 the Observatory came under the administration of the US Geological Survey, and the same year marked the first issue of Volcano Letter, an irregular periodical that carried news and volcano commentary from around the world until publication ceased in 1955. HVO has pioneered many approaches to monitoring of active volcanoes, and been instrumental in advancing understanding of ocean island volcanism.