BackgroundThe extensively eroded, elongated Koolau basaltic shield volcano of Pliocene-to-Pleistocene age forms much of the eastern half of Oahu Island. A lengthy NW rift zone is defined by a dike complex that runs the length of the windward coast. The largest documented submarine landslide of the Hawaiian islands produced the Nuuanu debris avalanche, which traveled 230 km NE from its source at the Nuuanu Pali on the NE side of the volcano. After a period of long quiescence activity resumed, forming the Honolulu volcanic series at the SE end of Oahu. The youngest members of the Honolulu Series, which consists of a group of tuff cones, maars, cinder cones, and spatter cones, many with associated lava flows, were considered by Stearns (1946) to be about 5000 years old. The youngest radiometric dates, however, ranged from 31,000 to 43,000 years old (Mullineaux et al., 1987), and more recent work (Ozawa et al., 2005) dated material to about 40,000 years. Sherrod (pers. comm., 2006) noted that earlier estimates of Holocene ages have been shown to be incorrect, and that the Sugarloaf lava flow, thought to be younger than 10,000 years, was dated at 110,000 years.
Source: Smithsonian / GVP volcano information
See also: Sentinel hub | Landsat 8