An aeromagnetic survey using an unmanned aerial vehicle over Azuma Volcano, NE Japan
| Autor: | Yonekura, Hikari, Ichiki, Masahiro, Okuma, Shigeo, Miyakawa, Ayumu, Tanaka, Ryo, Kaidao, Toshiki, Ayuta, Tsuge, Ohta, Toyonobu, Hashimoto, Takeshi |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| Popis: | The volcanic alteration zone at a depth of several hundred meters below the surface is a key feature to assess the degree of the imminence of phreatic eruption; Recent magnetotelluric images indicate that the conductive alteration zone prevents hypocenters of volcanic earthquakes from reaching the surface（Tsukamoto et al., 2018; Tseng et al., 2020; Gresse et al., 2021). A phreatic eruption could occur, when the hypocenters pass through the conducting layer. To approach the surface alteration zone and demagnetized area in the active volcanic edifice, a total intensity aeromagnetic survey using an unmanned aerial vehicle was carried out in 1×2.5 km over Oana Crater, with now on active fumaroles inside, of Mt. Azuma, NE Japan.The original magnetic anomaly distribution was obtained using Nakatsuka and Okuma (2006) with correcting the main field (IGRF-13) and the diurnal variations. The average magnetization intensity (AMI) was 2.06 A/m estimated by a statistical correlation method (Grauch 1987). After subtracting the contribution of the average magnetization from the original magnetic anomaly, the resultant magnetic anomaly data were inverted into a three-dimensional subsurface magnetization perturbation from AMI using the effective source volume minimization method (Nakatsuka and Okuma, 2014).The result shows a weakly magnetized region below the Tsubakurozawa Crater, where the past eruption occurred in 1893, 1896, juxtaposed with Oana Crater. The weakly magnetized location coincides with the demagnetization source location modeled by using the repeating total magnetic intensity observations (Japan Meteorological Agency, 2020). The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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