[SVC47-P24] Vertical ground deformation of Ioyama, Kirishima volcanoes measured by precise leveling survey (during Mar. 2012 - Nov. 2016)
Keywords:Ioyama, precise leveling survey, vertical deformation
From the surveyed leveling data in November 2016, the vertical displacements indicate the ground uplift at all bench marks. In this study, the reference bench mark is BM1120 at the western flank of Ioyama. The amount of maximum uplift is about 17.2 mm near the summit referred to BM1120 in November 2016. We estimated pressure source models based on the vertical deformation. We supposed the presence of an inflation spherical source as Mogi’s model, the depth has been inferred about 700 m. The lower limit of low resistivity layer assumed to be the clay layter is estimated in this depth (Aizawa et al., 2013). Accordingly, the inflation source by using precise leveling survey is located under the impermeable clay layer. In addition, the increase of pressure source volume since June 2015 is detected 4.8× 104 m3 in November 2016.