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| Titel |
Development of a Joint Inversion Technique using Gravimetric and Muon-radiographic Data for Resolving Three-dimensional Density Structure of a Gigantic Body |
| VerfasserIn |
R. Nishiyama, H. Tanaka, Y. Tanaka, S. Okubo, H. Oshima, T. Maekawa |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063271
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| Zusammenfassung |
| We have developed a method of analyzing gravimetric and muon-radiographic data for
visualizing a three-dimensional density structure of a volcano. The method searches for a
density structure that best explains the muon and gravity data simultaneously. For finding a
solution, techniques in least-squares inversion were employed. According to the model
simulation we have conducted, this new method was proved to have higher potential than
previous gravimetric inversion and previous muon tomography [Taira,2010; Tanaka et
al.,2010].
As a demonstration, we applied this method to Mt. Showa-Shinzan lava dome, Hokkaido,
Japan. At this site, muon observation has already been performed with emulsion cloud
chamber (ECC). The effective area of ECC was 1200 cm2, and the exposure time
was 4 month.Tanaka et al.,[2007] calculated the amount of matter on the muon
trajectories in the unit of gcm-2 (density times length). In addition to the muon data, we
newly collected gravity data at 35 stations on / around the lava dome. The data was
measured by using a LaCoste Romberg Gravimeter (G-875). Position of a gravity
station was determined by GPS interferometry between a reference station and a
moving station. Thereby, we conducted joint inversion of the muon and gravity
data.
The joint inversion yielded us the three-dimensional density profile of Mt.Showa-Shinzan.
The density profile suggested the two features of the dome. Firstly, lava had intruded beneath
the dome in a cylindrical shape whose diameter was 300 meter. This is inferred by the
existence of high density(Ï > 2.4g-cc) region localized at an altitude of 220 ~ 260 meter.
Secondly, we found a ultra high density region which was suspected to be a spine spreading
vertically near the top of the dome.
References
[1]Â Â Â Tanaka et al. (2007),Geophys. Res. Lett., 34, L22311.
[2]Â Â Â Tanaka et al. (2010),J. Geophys. Res., 115, B12332. |
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