An extract on #maui
Native Hawaiian tradition gives the origin of the island's name in the legend of Hawaiiloa, the navigator credited with discovery of the Hawaiian Islands. According to it, Hawaiiloa named the island after his son, who in turn was named for the demigod Mui. The earlier name of Maui was Ihikapalaumaewa. The Island of Maui is also called the "Valley Isle" for the large isthmus separating its northwestern and southeastern volcanic masses.
Maui's diverse landscapes are the result of a unique combination of geology, topography, and climate. Each volcanic cone in the chain of the Hawaiian Islands is built of dark, iron-rich/quartz-poor rocks, which poured out of thousands of vents as highly fluid lava over a period of millions of years. Several of the volcanoes were close enough to each other that lava flows on their flanks overlapped one another, merging into a single island. Maui is such a "volcanic doublet," formed from two shield volcanoes that overlapped one another to form an isthmus between them.
The older, western volcano has been eroded considerably and is cut by numerous drainages, forming the peaks of the West Maui Mountains (in Hawaiian, Mauna Kahalawai). Puu Kukui is the highest of the peaks at 5,788 feet (1,764 m). The larger, younger volcano to the east, Haleakal, rises to more than 10,000 feet (3,000 m) above sea level, and measures 5 miles (8.0 km) from seafloor to summit.
The eastern flanks of both volcanoes are cut by deeply incised valleys and steep-sided ravines that run downslope to the rocky, windswept shoreline. The valley-like Isthmus of Maui that separates the two volcanic masses was formed by sandy erosional deposits.
Maui's last eruption (originating in Haleakal's Southwest Rift Zone) occurred around 1790; two of the resulting lava flows are located (1) at Cape Knau between hihi Bay and La Perouse Bay on the southwest shore of East Maui, and (2) at Makaluapuna Point on Honokahua Bay on the northwest shore of West Maui. Although considered to be dormant by volcanologists, Haleakal is certainly capable of further eruptions.
Maui is part of a much larger unit, Maui Nui, that includes the islands of Lnai, Kahoolawe, Molokai, and the now submerged Penguin Bank. During periods of reduced sea level, including as recently as 20,000 years ago, they are joined together as a single island due to the shallowness of the channels between them.