Crustal magma pathway beneath Aso caldera inferred from three-dimensional electrical resistivity structure

• Hata, Maki

• Takakura, Shinichi

• Matsushima, Nobuo

• Hashimoto, Takeshi

• Utsugi, Mitsuru

Abstract

At Naka-dake cone, Aso caldera, Japan, volcanic activity is raised cyclically, an example of which was a phreatomagmatic eruption in September 2015. Using a three-dimensional model of electrical resistivity, we identify a magma pathway from a series of northward dipping conductive anomalies in the upper crust beneath the caldera. Our resistivity model was created from magnetotelluric measurements conducted in November–December 2015; thus, it provides the latest information about magma reservoir geometry beneath the caldera. The center of the conductive anomalies shifts from the north of Naka-dake at depths >10 km toward Naka-dake, along with a decrease in anomaly depths. The melt fraction is estimated at 13–15% at ~2 km depth. Moreover, these anomalies are spatially correlated with the locations of earthquake clusters, which are distributed within resistive blocks on the conductive anomalies in the northwest of Naka-dake but distributed at the resistive sides of resistivity boundaries in the northeast.

Journal

• Geophysical Research Letters

  Geophysical Research Letters 43 (20), 10-10, 2016-10-28

  American Geophysical Union

Details

• CRID: 1050564288976224000
• NII Article ID: 120006220018
• HANDLE: 2115/65174
• ISSN: 00948276
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles