MOUNT FUJI GEOLOGY
Scientists have
identified four distinct phases of volcanic activity in the formation of
Mt. Fuji. The first phase, called Sen-komitake, is composed of an andesite
core recently discovered deep within the mountain. Sen-komitake was
followed by the "Komitake Fuji," a basalt layer believed to be formed
several hundred thousand years ago. Approximately 100,000 years ago, "Old
Fuji" was formed over the top of Komitake Fuji. The modern, "New Fuji" is
believed to have formed over the top of Old Fuji by around 10,000 years
ago.
The volcano is currently classified as active with a low risk of eruption.
The last recorded eruption occurred in very recent geological time of 1707
during the Edo period. At this time, a new crater, along with a second
peak, named Hōei-zan after the era name, formed halfway down its side.
Mt. Fuji is where the Eurasian Plate (or the Amurian Plate), the Okhotsk
Plate, and the Philippine Plate meet. They form the western part of Japan,
the eastern part of Japan, and the Izu Peninsula respectively.
(Article
based on
Wikipedia article and used under the
GNU Free Documentation License)
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