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A volcanic arc (also known as a magmatic arc [1]: 6.2 ) is a belt of volcanoes formed above a subducting oceanic tectonic plate, [2] with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench , with the arc located further from the subducting plate than the trench.
Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of the calc-alkaline magmas. Some Island arcs have distributed volcanic series as can be seen in the Japanese island arc system where the volcanic rocks change from tholeiite—calc-alkaline—alkaline with increasing distance from the trench. [15]
The geology of Antigua and Barbuda is part of the Lesser Antilles volcanic island arc. Both islands are the above water limestone "caps" of now inactive volcanoes. The two islands are the surface features of the undersea Barbuda Bank and have karst limestone landscapes. [1] Barbuda is primarily flat and formed from coral reefs.
Nishinoshima (Japanese: 西之島, "western island") is a volcanic island located around 940 km (584 mi) south-southeast of Tokyo that is part of the Volcano Islands arc. . Nishinoshima is located about 130 km to the west of the nearest inhabited Ogasawara islands, Chichijima Island, hence the name; the other Ogasawara island groups are aligned more to the north–
A volcanic arc is a chain of volcanic islands or mountains located near the edge of continents that are formed as the result of tectonic plate subduction. Subcategories This category has the following 7 subcategories, out of 7 total.
Volcanic islands usually range in size between 1 and 104 square kilometres (0.4 and 40 sq mi). [2] Islands above a certain size usually have fresh groundwater, while low islands often do not, so volcanic islands are more likely to be habitable.
The Tonga–Kermadec Ridge is an oceanic ridge in the south-west Pacific Ocean underlying the Tonga–Kermadec island arc.It is a result of the most linear, fastest converging, and seismically active subduction boundary on Earth, the Kermadec–Tonga subduction zone, and consequently has the highest density of submarine volcanoes.
Ash plume from Ambrym Volcano, October 4, 2004. Ambrym is a large basaltic volcano with a 12-km-wide caldera, and is one of the most active volcanoes of the New Hebrides volcanic arc. The caldera is the result of a huge Plinian eruption, which took place around AD 50.