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The Japan, Taiwan, Marianas Region
Human settlement of Japan can be traced for tens of thousands of years and through an unbroken line of emperors from 660 BC. In 552 AD, Buddhism was introduced from Korea, and Japan's first confirmed historical eruption was in 664 AD at Oshima. A fixed capital at the present location of Nara was first established in 710. By the time of Japan's largest historical eruption (Towada, 915 AD), 19 Japanese volcanoes had been documented in eruption, more than the rest of the world combined (including 10 in Europe). It was not until 1626, however, that history recorded an eruption from Japan's northern island of Hokkaido, and it was not formally made part of Japan until 1868. A feudal system had dominated all of Japan from 1192, but in 1868, 14 years after the nation was first opened to western trade, the Emperor Meiji overcame shogun power, and Edo (renamed Tokyo, or Eastern Capital) became Japan's capital city.
To the south, the Mariana Islands were populated from 1500 BC and explored by Spaniards in the 15th century AD, but the islands did not come under Spanish colonial rule until 1668. The first historical eruption was documented the following year. The northern volcanic islands were sold to Germany in 1898, occupied by Japan between the two World Wars, and named a Trust Territory by the UN in 1947 administered by the US. The islands became a self-governing US commonwealth in 1975. Region 08's total land area approximates California's, but its population is 4 times as large, and the Marianas constitute only 0.1% of each.
Most volcanoes in this region result from subduction of westward-moving oceanic crust under the Asian Plate. In the Izu-Mariana chain, however, the crust to the west is also oceanic, forming more basaltic island arcs (but with volcanoes that are far more explosive than oceanic hotspot volcanoes).
Japan's long history and careful attention to tephrochronology have produced an unusually detailed and balanced record of Holocene volcanism. One result of this work is that this region now leads all others in the total number of dated eruptions (1465) and number of volcanoes with dated eruptions (106). Several regions in which tephrochronology is emphasized, such as New Zealand and the Mediterranean, show a high proportion of their large eruptions (VEI ?4) more than 2000 years ago. In contrast, regions such as Latin America, Indonesia, and the Philippines, show them concentrated in the last 200 years of historical records. Japan, however, (along with Kamchatka, Iceland, and Alaska) shows a balanced temporal distribution of large eruptions, reflecting both tephrochronology emphasis and vigorous explosive volcanism during recent centuries.
The volcanoes of this region are unusually explosive, and include Kikai in the Ryukyu Islands immediately south of Kyushu, which produced one of the earth's largest Holocene explosive eruptions about 6300 radiocarbon years ago. Lake-filled Towada volcano in northern Honshu has an average VEI of 4.42, the world's highest of those with 5 or more VEI assignments. Mashu, another caldera volcano in Hokkaido, is another of only 8 volcanoes globally with an average VEI of 4 or higher. Japan leads the world in volcanoes with average VEIs of 3 or larger, and no other region has documented more large (VEI ?4) explosive eruptions (114), or approaches its total of 58 eruptions of this magnitude in the past 2000 years.
Region 08 has the largest number of submarine volcanoes, mostly extending down the Izu-Marianas arc, contributing the many submarine eruptions around the Pacific's 'Ring of Fire.' The many reports of water discoloration over submarine vents have also contributed to this region's record number (292) of eruptions preceded by a question mark, indicating uncertainty that the eruption actually took place. Recent bathymetric expeditions have uncovered evidence for young submarine volcanism in the Marianas arc, including first-hand observations of active explosive and effusive eruptions from NW Rota-I volcano beginning in 2004. Vigorous submarine activity in this region, in combination with that at Melanesia and the New Zealand to Fiji regions, accounts for more than half of the world's 100 documented eruptions that have built oceanic islands.
List of Holocene volcanoes in the Japan, Taiwan, Marianas region.