Fig. 15
![Fig. 15](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40623-018-0941-2/MediaObjects/40623_2018_941_Fig15_HTML.png)
Two 3-D Vs structures located 6 km beneath Aso caldera. Cross sections provide perspectives from the a south and b north. The black triangle marks the location of the Nakadake crater. Red shapes indicate Vs = 2.0 km/s and blue shapes indicate Vs = 4.0 km/s. H1–H3 and L1–L4 are the same velocity anomalies as displayed in Fig. 14