Fig. 1From: Estimating the ashfall volume for a small eruption using ellipse-approximated isopach analysis: how many seeking points are required to determine a suitable axis?Location index map of the Kirishima Volcano Group. a Index map of western Japan. VF: volcanic front. MTL: median tectonic line fault zone. b Shading relief map of the Kirishima Volcano Group obtained using the website of the Geospatial Information Authority of JapanBack to article page