Global Volcanism Program

Volcanoes of the World

Volcanoes of Japan, Taiwan, and the Marianas

	Hokkaido
	Honshu
	Kyushu, Ryukyu Islands, and Taiwan
	Izu, Volcano, and Mariana Islands

Regional Volcanology Highlights from Simkin and Siebert, 1994.

Human settlement of Japan can be traced for tens of thousands of years, and an unbroken line of emperors from 660 BC. Japan's first documented historical eruption was from Aso, its most prolific volcano, in 553 AD, the year after Buddhism was introduced from Korea. A fixed capital was first established in 710. By the time of Japan's largest historical eruption (Towada, 915 AD), 17 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.

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 four times as large, and the Marianas constitute only 0.1% of each.

Japan's long history and careful attention to tephrochronology have produced an unusally 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 (1274) and number of volcanoes with dated eruptions (94).

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 2,000 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, which produced one of the earth's largest Holocene explosive eruptions about 6,300 radiocarbon years ago. No other region has documented more large explosive eruptions (VEI >= 4), or approaches its total of 41 AD eruptions of this magnitude. Pyroclastic flows have accompanied a record 28% of its eruptions, including the current Unzen eruption.

Most volcanoes in this region result from subduction of westward-moving oceanic crust under the Asian Plate. In the Izu-Marianas chain, however, the crust to the west is also oceanic, forming island arcs where volcanoes are largely basaltic but far more explosive than oceanic hotspot volcanoes.

Region 08 has the largest number of submarine volcanoes, mostly extending down the Izu-Marianas arc, and the largest number of reported submarine eruptions. The many reports of water discoloration over submarine vents have also contributed to this region's record number (180) of eruptions preceded by a question mark, indicating uncertainty that the eruption actually took place. In nearly equal proportions, Regions 08, 06, and 04 account for nearly 3/4ths of the eruptions that have built oceanic islands. Region 08 has also recorded the largest number of phreatic eruptions (232), nearly double those of the closest contender.