The Japan Meteorological Agency has issued a warning for people to keep away from the Mount Zaō volcanic complex, which straddles the border between Yamagata and Miyagi prefectures on Honshū Island, Japan, after a series of small seismic tremors were detected beneath the area on Tuesday 30 January 2018, as well as a slight swelling of the ground. The tremors are thought to have been caused by the movement of hot water and volcanic gas, which could indicate that the volcano is about to erupt.
The Mount Zaō volcanic complex on Honshū Island, Japan. Kyodo News Agency.
Japan has a complex tectonic situation, with parts of the country on four different tectonic plates. Kyushu Island lies at the northeast end of the Ryukyu Island Arc, which sits on top of the boundary between the Eurasian and Philippine Plates. The Philippine Plate is being subducted beneath the Eurasian Plate, in the Ryukyo Trench, to the Southeast of the Islands. As it is drawn into the interior of the Earth, the tectonic plate is partially melted by the heat of the Earth's interior, and liquid magma rises up through the overlying Eurasian Plate to form the volcanoes of the Ryukyu Islands and Kyushu.
The movement of the Pacific and Philippine Plates beneath eastern Honshu. Laurent Jolivet/Institut des Sciences de la Terre d'Orléans/Sciences de la Terre et de l'Environnement.
Follow Sciency Thoughts on Facebook.