Fig. 6

Migration of the inflation peak. Spatial distribution of uplift and quasi uplift for a 2014–2016, b 2016–2017, and c 2017–2018 around the eruptive vents formed on April 19, 2018. Line 1 and 2 indicate the meridian running through the inflation peaks during 2014–2016 and 2016–2018. The black arrow indicates migration distance between inflation peaks during 2014–2016 (red points) and 2016–2018 (blue points). The white circles indicate fumarole vents A and H and mud pot F. The black solid and dashed ellipsoids indicate the eruptive vents generated in the 2018 eruption and the 1768 eruption, respectively. The rectangles indicate sill-like crack geometry estimated during 2014–2016