Mount Aso: the largest active volcano in Japan

Today’s Video of the Day from the European Space Agency features Mount Aso, which is the largest active volcano in Japan.

Mount Aso is located in the Kumamoto Prefecture on Kyushu, Japan’s southernmost major island. The volcano rises to an elevation of 1,592 meters. 

“The caldera was formed during four major explosive eruptions from approximately 90,000 to 270,000 years ago,” reports ESA. “These produced voluminous pyroclastic flows and volcanic ash that covered much of Kyushu region and even extended to the nearby Yamaguchi Prefecture.”

“The caldera is surrounded by five peaks known collectively as Aso Gogaku: Nekodake, Takadake, Nakadake, Eboshidake, Kishimadake. Nakadake is the only active volcano at the centre of Mount Aso and is the main attraction in the region.” 

“The volcano goes through cycles of activity. At its calmest, the crater fills with a lime green lake which gently steams, but as activity increases, the lake boils off and disappears. The volcano has been erupting sporadically for decades, most recently in 2021, which has led to the number of visitors drop in recent years.”

Located near the crater, Kusasenri is a vast grassland inside the mega crater of Eboshidake, which was active just over 20,000 years ago. The land is used for dairy farming and horseback riding. 

Japan has 110 active volcanoes – 47 of are monitored closely as they have erupted recently or shown worrying signs including seismic activity, ground deformation or emissions of large amounts of smoke, according to ESA.

“Satellite data can be used to detect the slight signs of change that may foretell an eruption. Once an eruption begins, optical and radar instruments can capture the various phenomena associated with it, including lava flows, mudslides, ground fissures and earthquakes. Atmospheric sensors on satellites can also identify the gases and aerosols released by the eruption, as well as quantify their wider environmental impact.”

Video Credit: ESA

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By Chrissy Sexton, Earth.com Staff Writer