BackgroundUdonejima, though techincally part of the Izu Volcanic Arc, is actually considered to be situated just behind the true volcanic front, along a line of volcanoes that is oblique to the Izu Trench. The volcanic rocks of this lineament are characterized by high-alumina basalts, calc-alkaline basalts, andesites, and rhyolites (Onuma et al., 1983). The andesites are rich in pyroxene, and the rhyolites often contain hypersthene, hornblende, and biotite (Onuma et al., 1983).
Source: Smithsonian / GVP volcano information
See also: Sentinel hub | Landsat 8