Detection of a crack-like conduit beneath the active crater at Aso volcano, Japan

Mare Yamamoto, Hitoshi Kawakatsu, Satoshi Kaneshima, Takehiko Mori, Tomoki Tsutsui, Yasuaki Sudo, Yuichi Morita

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62 Citations (Scopus)


To constrain the source of long period tremors (LPTs), we deployed a very dense broadband seismic network consisting of totally twenty-four stations around the active crater of Aso volcano in Kyushu, Japan. The spatial variation of the observed signal amplitudes reveals that the source of LPTs consists of an isotropic expansion (contraction) and an inflation (deflation) of an inclined tensile crack with a strike almost parallel to the chain of craters. The detected crack has a dimension of 1 km and its center is located a few hundred meters southwest of the active crater, at a depth of about 1.8 km. The extension of the crack plane meets the crater chain including the active fumarole at the surface, suggesting that the crack has played an important role in transporting gasses and/or lava to the craters from below. This work also demonstrates a powerful usage of broadband seismometers as geodetic instruments to constrain subsurface structures at active volcanoes.

Original languageEnglish
Pages (from-to)3677-3680
Number of pages4
JournalGeophysical Research Letters
Issue number24
Publication statusPublished - Dec 15 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • General Earth and Planetary Sciences


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