Evaluation of Caldera Hosted Geothermal Potential during Volcanism and Magmatism in Subduction System, NE Japan

Figure 7

Seismic tomography maps showing (a) primary wave (P-wave) velocity perturbation (%), (b) secondary wave (S-wave) velocity perturbation (%), and (c) Poisson’s ratio, modified from Nakajima et al. [42]. A zone of low seismic velocity at depths of 5 and 10 km is observed in the study area (open square), indicated by a lighter shade. This zone is suggested to indicate the vertical extent of the magma chamber, in agreement with our study. The slightly higher Poisson’s ratio observed at a depth of 5 km indicates the existence of melt- or H₂O-filled pores. Black dots show earthquake swarms within ±2.5 km of the corresponding depth.