Radiographic imaging below a volcanic crater floor with cosmic-ray muons

Hiroyuki K.M. Tanaka, Toshiyuki Nakano, Satoshi Takahashi, Junnya Yoshida, Minoru Takeo, Jun Oikawa, Takao Ohminato, Yosuke Aoki, Etsuro Koyama, Hiroshi Tsuji, Hiromitsu Ohshima, Tokumitsu Maekawa, Hidefumi Watanabe, Kimio Niwa

研究成果: Article査読

32 被引用数 (Scopus)


We present a novel application of cosmic-ray muon radiography to image the shallow density structure beneath Asama Volcano, Japan. We use a single detector (emulsion cloud chamber) set up in an underground vault at an elevation of 2250 m on the eastern flank of Asama, 310 m below the summit of the edifice and 1 km away from the crater. The results point to two high-density anomalies located between the original pre-2004 eruption crater floor and post-2004 eruption crater profile. A third low-density anomaly is imaged immediately below the pre-2004 eruption crater floor. The spatial extent of each density anomaly is about 100 to 200 m. To know if this method, applied to other volcanoes, would produce contrasting results, we performed the measurement in 1944 Usu lava dome. We confirmed a bulbous shape measuring approximately 300 m in diameter and narrowing downwards. The diameter of the uppermost part of the conduit is estimated at 100 ± 15 m at an elevation of 260 m a.s.l. and 50 ± 15 m at an elevation of 217 m a.s.l., demonstrating a resolution that is significantly better than that typically achieved with seismic tomography based on picks of first arrival times from earthquakes or artificial sources.

ジャーナルAmerican Journal of Science
出版ステータスPublished - 2008 9月

ASJC Scopus subject areas

  • 地球惑星科学(全般)


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