A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers
<p>One of the key challenges for muographic studies is to reveal the detailed 3D density structure of a volcano by increasing the number of observation directions. 3D density imaging by multi-directional muography requires that the individual differences in the performance of the installed muo...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-03-01
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| Series: | Geoscientific Instrumentation, Methods and Data Systems |
| Online Access: | https://gi.copernicus.org/articles/11/127/2022/gi-11-127-2022.pdf |
| _version_ | 1818774288259350528 |
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| author | S. Miyamoto S. Nagahara S. Nagahara K. Morishima T. Nakano M. Koyama Y. Suzuki |
| author_facet | S. Miyamoto S. Nagahara S. Nagahara K. Morishima T. Nakano M. Koyama Y. Suzuki |
| author_sort | S. Miyamoto |
| collection | DOAJ |
| description | <p>One of the key challenges for muographic studies is to reveal the detailed
3D density structure of a volcano by increasing the number of observation
directions. 3D density imaging by multi-directional muography requires that
the individual differences in the performance of the installed muon
detectors are small and that the results from each detector can be derived
without any bias in the data analysis. Here we describe a pilot muographic
study of the Izu–Omuroyama scoria cone in Shizuoka Prefecture, Japan, from
11 directions, using a new nuclear emulsion detector design optimized for
quick installation in the field. We describe the details of the data
analysis and present a validation of the results.</p>
<p>The Izu–Omuroyama scoria cone is an ideal target for the first
multi-directional muographic study, given its expected internal density
structure and the topography around the cone. We optimized the design of the
nuclear emulsion detector for rapid installation at multiple observation
sites in the field, and installed these at 11 sites around the volcano. The
images in the developed emulsion films were digitized into segmented tracks
with a high-speed automated readout system. The muon tracks in each emulsion
detector were then reconstructed. After the track selection, including
straightness filtering, the detection efficiency of the muons was estimated.
Finally, the density distributions in 2D angular space were derived for each
observation site by using a muon flux and attenuation models.</p>
<p>The observed muon flux was compared with the expected value in the free sky,
and is 88 % <span class="inline-formula">±</span> 4 % in the forward direction and 92 % <span class="inline-formula">±</span> 2 % in the backward direction. The density values were validated by
comparison with the values obtained from gravity measurements, and are
broadly consistent, except for one site. The excess density at this one site
may indicate that the density inside the cone is non-axisymmetric, which is
consistent with a previous geological study.</p> |
| first_indexed | 2024-12-18T10:38:46Z |
| format | Article |
| id | doaj.art-10a0267c13704785bc521a09335b78ed |
| institution | Directory Open Access Journal |
| issn | 2193-0856 2193-0864 |
| language | English |
| last_indexed | 2024-12-18T10:38:46Z |
| publishDate | 2022-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Instrumentation, Methods and Data Systems |
| spelling | doaj.art-10a0267c13704785bc521a09335b78ed2022-12-21T21:10:41ZengCopernicus PublicationsGeoscientific Instrumentation, Methods and Data Systems2193-08562193-08642022-03-011112714710.5194/gi-11-127-2022A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambersS. Miyamoto0S. Nagahara1S. Nagahara2K. Morishima3T. Nakano4M. Koyama5Y. Suzuki6Earthquake Research Institute, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, JapanEarthquake Research Institute, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, JapanGraduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe, Hyogo, 657-8501, JapanFundamental Particle Physics Laboratory, Graduate School of Science of Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi, 464-8602, JapanFundamental Particle Physics Laboratory, Graduate School of Science of Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi, 464-8602, JapanCenter for Integrated Research and Education of Natural Hazards, Shizuoka University, 836 Oya, Suruga-ku, Shizuoka City, Shizuoka, JapanSTORY, Ltd., 2-2-5-2321, Minatomachi, Naniwa-ku, Osaka City, Osaka, Japan<p>One of the key challenges for muographic studies is to reveal the detailed 3D density structure of a volcano by increasing the number of observation directions. 3D density imaging by multi-directional muography requires that the individual differences in the performance of the installed muon detectors are small and that the results from each detector can be derived without any bias in the data analysis. Here we describe a pilot muographic study of the Izu–Omuroyama scoria cone in Shizuoka Prefecture, Japan, from 11 directions, using a new nuclear emulsion detector design optimized for quick installation in the field. We describe the details of the data analysis and present a validation of the results.</p> <p>The Izu–Omuroyama scoria cone is an ideal target for the first multi-directional muographic study, given its expected internal density structure and the topography around the cone. We optimized the design of the nuclear emulsion detector for rapid installation at multiple observation sites in the field, and installed these at 11 sites around the volcano. The images in the developed emulsion films were digitized into segmented tracks with a high-speed automated readout system. The muon tracks in each emulsion detector were then reconstructed. After the track selection, including straightness filtering, the detection efficiency of the muons was estimated. Finally, the density distributions in 2D angular space were derived for each observation site by using a muon flux and attenuation models.</p> <p>The observed muon flux was compared with the expected value in the free sky, and is 88 % <span class="inline-formula">±</span> 4 % in the forward direction and 92 % <span class="inline-formula">±</span> 2 % in the backward direction. The density values were validated by comparison with the values obtained from gravity measurements, and are broadly consistent, except for one site. The excess density at this one site may indicate that the density inside the cone is non-axisymmetric, which is consistent with a previous geological study.</p>https://gi.copernicus.org/articles/11/127/2022/gi-11-127-2022.pdf |
| spellingShingle | S. Miyamoto S. Nagahara S. Nagahara K. Morishima T. Nakano M. Koyama Y. Suzuki A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers Geoscientific Instrumentation, Methods and Data Systems |
| title | A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| title_full | A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| title_fullStr | A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| title_full_unstemmed | A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| title_short | A muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| title_sort | muographic study of a scoria cone from 11 directions using nuclear emulsion cloud chambers |
| url | https://gi.copernicus.org/articles/11/127/2022/gi-11-127-2022.pdf |
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