[SEM21-P01] 3-D resistivity models beneath two active volcano groups in a graben by Network-MT data of reticular arrangements (2)
In and around Aso caldera and Unzen volcano, network-MT surveys for measuring the electric potential difference (the electric field) were carried out during 1993–1998 by using long metallic wires/dipoles of the commercial telephone company's networks [e.g., Uyeshima et al., 1995; Tanaka et al., 1998; Hashimoto et al., 1999; Hata et al., 2015]. We determined two components of network-MT response functions between the potential differences for respective dipoles and the two horizontal components of the magnetic field at the Kanoya Geomagnetic Observatory. Three-dimensional (3-D) inversion analyses were performed for obtaining each electrical resistivity model beneath Aso caldera and Unzen volcano. In the inversion analyses, we used a data-space inversion code, which can be taken into account the length and direction of respective dipoles [e.g., Siripunvaraporn et al., 2004]. Moreover, two data sets in a period range from 480 to 20,480 s, which are distributed as to respectively cover the two target regions (Aso caldera and Unzen volcano) with reticular dipole arrangement, were used for obtaining well-resolved 3-D models. In this presentation, we show magma supply systems inferred from the 3-D resistivity models beneath Aso caldera and Unzen volcano.