The Volcanoes Across Japan

Japan is an arch of mountains and volcanoes. The volcanoes of Japan are much like the volcanoes of Hawaii; many clustered volcanoes make up the little islands on the east side of Japan. This long cluster forms the northeastern part of Japan, while more volcanic arcs create the southeastern parts. History of volcanic movement can be tracked through the ages of the magma, the oldest being in the southwest, the newest south east. With this, like seafloor spreading, we can see the possible movements Japan has made throughout the centuries. Like previously stated, Japan has about one-tenth of the worlds active volcanoes. This does not include the hundreds of inactive volcanoes that litter on the Japanese archipelago; 40 active to the 180 known inactive. The most famous active volcano in Japan is Mt. Fuji.

Scientists have found that around 100,000 years ago the mountain was Komitake Fuji. This volcano erupted and another mountain took its place, "Old Fuji". Approximately 10,000 years ago, "New Fuji" was formed over the top of "Old Fuji" when that volcano erupted. The eruption in the 1700 did not change the volcano like the other eruptions did but the fact that there are at least three volcano in the form of on giant volcano is amazing.
Here in the first few seconds of this movie is an example of an all too frequent happening throughout Japan.



Another example of often occurring volcanoes is the undersea volcanoes off the coast of Japan. These can be seen erupting mostly in the western Pacific. The change in the color of the water is often spotted by fishermen and it isn't too much later that the smoke can be visibly seen, generally over many miles of ocean surface. One notoriously stubborn volcano called Fukutoku Okanoba, continuously rises and falls going from visible to not over long periods of time due to the eruptions and then the erosion that follows. The recorded years of appearance are 1904, 1914, and 1986. Within two years these appearances were completely unapparent. Most impressively, in 1914, Fukutoku Okanoba raised to around 985 feet with a circumference of about 7.5 miles; this with no exception to the general 2 year erosion time.