Special issue “Advancement of our knowledge on Aso volcano: current activity and background”

Abstract

© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Introduction Aso volcano is one of the most active volcanoes in Japan located in the volcanic front on Kyushu-Ryuku Island arc. Central cones including the active Nakadake cone located inside the caldera which was formed by four pyroclastic flow eruptions. The Nakadake cone hosts a hot and acid crater lake and frequent phreatic-to-magmatic eruptions. From gigantic caldera-forming eruptions to fumarolic activities, Aso volcano provides us with a wide-range of research subjects which improve our understandings of the volcanic system. The most recent magmatic eruptions at Aso volcano characterized by Strombolian explosions and continuous ash venting, began on 25 November 2014, after about 20 years of dormancy. In late 2015 and 2016, violent phreatic and phreatomagmatic explosions occurred repeatedly. This special issue focuses on scientific researches at Aso volcano completed before, during, and after the 2014–2016 eruptive activities. In total, 19 articles were published in the special issue; these are described accordingly with the investigating methods.