Aogashima Volcano, Japan

Geology

Aogashima is a complex structure Quaternary volcanic island three.5 metric linear unit in length with a most breadth of two.5 km, formed by the overlapping remnants of at least four submarine calderas. The island is surrounded by terribly steep rugged cliffs of superimposed volcanic deposits. The southern coast also rises to a sharp ridge forming one fringe of a crater named Ikenosawa (池之沢?) with a diameter of one.5 km. The caldera dominates the island, with one point on its southern ridge, Otonbu (大凸部?) with a height of 423 metres (1,388 ft), as the island's highest point. The caldera is occupied by a subordinate cone named Maruyama (丸山?).
Still considered a Class-C active volcano by the Japan meteoric Agency, the last volcanic eruption of Aogashima was during a four-year amount from 1781–1785.

History

The history of human settlement on Aogashima is unknown. Most of the people in Aogashima square measure Japanese. The island was mentioned in Edo period records unbroken at Hachijō-jima, which record volcanic activity in 1652, and from 1670–1680. An earthquake flight in July 1780 was followed by condensation rising from the lakes in the Ikenosawa crater. Further earthquakes in might 1781 diode to associate degree eruption. In April 1783, lava run from the Maruyama cone resulted in the evacuation of all sixty three households on the island. During a large volcanic eruption in 1785, some 130–140 of the population of 327 islanders perished.