Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption
Abstract We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (M s), saturation rema...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-02-01
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| Series: | Earth, Planets and Space |
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| Online Access: | https://doi.org/10.1186/s40623-023-01783-x |
| _version_ | 1797865339455799296 |
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| author | Chisato Anai Takahiro Ohkura Shin Yoshikawa Nobutatsu Mochizuki |
| author_facet | Chisato Anai Takahiro Ohkura Shin Yoshikawa Nobutatsu Mochizuki |
| author_sort | Chisato Anai |
| collection | DOAJ |
| description | Abstract We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (M s), saturation remanent magnetization (M rs), coercivity (B c), and coercivity of remanence (B cr), were obtained. Curie temperature (T c) of the samples was also estimated using thermomagnetic analyses. Titanium-rich and -poor titanomagnetites were the dominant magnetic minerals in the volcanic ash, of which the titanium-rich phase was dominant. Systematic magnetic measurements of the volcanic ash ejected during the 1-year eruption event indicate that temporal changes in the hysteresis parameters occurred throughout the event. These temporal changes suggest that the M rs/M s and B c values of the volcanic ash increased considerably during several periods. The clear increases in M rs/M s and B c, associated with the central peak in FORC diagrams, indicate that non-interacting single-domain grains increased. For these high M rs/M s and B c samples, thermal demagnetizations of 3-axis IRM show that the low unblocking-temperature component up to 250–300 °C has apparently higher coercivity, suggesting that the above-mentioned, non-interacting single-domain grains are Ti-rich titanomagnetite. Interestingly, the high M rs/M s and B c values were synchronous with observations of volcanic glow. These results suggest that changes in the magnetic properties of titanomagnetite grains in volcanic ash reflect changes in physical conditions from the vent to the conduit of the volcano. Graphical Abstract |
| first_indexed | 2024-04-09T23:06:26Z |
| format | Article |
| id | doaj.art-92c2689bd2004616b0ec06211adf44f4 |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-04-09T23:06:26Z |
| publishDate | 2023-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-92c2689bd2004616b0ec06211adf44f42023-03-22T10:40:04ZengSpringerOpenEarth, Planets and Space1880-59812023-02-0175111110.1186/s40623-023-01783-xTemporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruptionChisato Anai0Takahiro Ohkura1Shin Yoshikawa2Nobutatsu Mochizuki3Aso Volcanological Laboratory, Kyoto UniversityAso Volcanological Laboratory, Kyoto UniversityAso Volcanological Laboratory, Kyoto UniversityDepartment of Earth and Environmental Science, Faculty of Advanced Science and Technology, Kumamoto UniversityAbstract We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (M s), saturation remanent magnetization (M rs), coercivity (B c), and coercivity of remanence (B cr), were obtained. Curie temperature (T c) of the samples was also estimated using thermomagnetic analyses. Titanium-rich and -poor titanomagnetites were the dominant magnetic minerals in the volcanic ash, of which the titanium-rich phase was dominant. Systematic magnetic measurements of the volcanic ash ejected during the 1-year eruption event indicate that temporal changes in the hysteresis parameters occurred throughout the event. These temporal changes suggest that the M rs/M s and B c values of the volcanic ash increased considerably during several periods. The clear increases in M rs/M s and B c, associated with the central peak in FORC diagrams, indicate that non-interacting single-domain grains increased. For these high M rs/M s and B c samples, thermal demagnetizations of 3-axis IRM show that the low unblocking-temperature component up to 250–300 °C has apparently higher coercivity, suggesting that the above-mentioned, non-interacting single-domain grains are Ti-rich titanomagnetite. Interestingly, the high M rs/M s and B c values were synchronous with observations of volcanic glow. These results suggest that changes in the magnetic properties of titanomagnetite grains in volcanic ash reflect changes in physical conditions from the vent to the conduit of the volcano. Graphical Abstracthttps://doi.org/10.1186/s40623-023-01783-xCoercivitySaturation magnetizationSaturation remanent magnetizationSingle domainVolcanic ashAso Nakadake volcano |
| spellingShingle | Chisato Anai Takahiro Ohkura Shin Yoshikawa Nobutatsu Mochizuki Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption Earth, Planets and Space Coercivity Saturation magnetization Saturation remanent magnetization Single domain Volcanic ash Aso Nakadake volcano |
| title | Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption |
| title_full | Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption |
| title_fullStr | Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption |
| title_full_unstemmed | Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption |
| title_short | Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019–2020 eruption |
| title_sort | temporal change in rock magnetic properties of volcanic ashes ejected during a 1 year eruption event a case study on the aso nakadake 2019 2020 eruption |
| topic | Coercivity Saturation magnetization Saturation remanent magnetization Single domain Volcanic ash Aso Nakadake volcano |
| url | https://doi.org/10.1186/s40623-023-01783-x |
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