Keywords:Aso Volcano, Eruption in 2014
Aso Volcano is located in the central part of the Beppu-Shimabara graben and consists of an elliptical caldera measuring 18 km (E-W) by 25 km (N-S), and of central cones with more than 10 volcanoes aligned in the E-W direction. Among central cones, Nakadake volcano is the only active one. The Nakadake is composed of seven craters, which are aligned in a N-S direction. Only the northernmost crater (1st crater) has been active during the past 80 years, and its recent activities are characterized by ash and strombolian eruptions and phreatic or phreatomagmatic explosions. The last strombolian eruptions ended in the middle of the 1990s and after that, surface activities have been restricted to the fumarolic gas and ash emission from the northernmost crater of the volcano accompanying activity of long period tremors (LPT).
Aso Volcanological Laboratory (AVL) has conducted geophysical studies of Aso volcano since 1928, through seismic, geodetic, geomagnetic and geothermal methods.
After 21 year's dormancy, magmatic eruptions were resumed from the 1st crater in November, 2014. In this presentation, summaries of the observation results before and during the 2014-2015 eruptive activities will be introduced.