Fig. 1
From: Magmatic–hydrothermal system of Aso Volcano, Japan, inferred from electrical resistivity structures
a Location of Aso Volcano (blue star) and nearby plate boundaries (black lines). b Topographic map of Aso Volcano. Blue crosses depict magnetotelluric (MT) sites used in the three-dimensional (3D) inversion. The number 022 refers to the site selected for the sensitivity tests. Open circles indicate hydrothermal manifestations (TAR: Tarutama hot spring, YUN: Yunotani fumarole, HON: Honzuka spring, UCH: Uchinomaki hot spring), and open squares indicate locations of wells (W1–W6) referred to in the text. The red star indicates the position of the source of deformation at 5 km BSL detected by Ohkura and Oikawa (2012). Open triangles show the five main post-caldera cones. The black line in the main panel indicates the caldera boundary. c A close-up view of the area indicated by the red square in the main panel. Blue crosses show the locations of the nine new sites for which data were used in this study. The black line indicates the perimeter of Naka-dake crater