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Effects of gas escape and crystallization on the complexity of conduit flow dynamics during lava dome eruptions
https://nied-repo.bosai.go.jp/records/4563
https://nied-repo.bosai.go.jp/records/4563e19843ad-bdac-4c23-9c6e-39f8adfe7e61
| Item type | researchmap(1) | |||||||||||||
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| 公開日 | 2023-04-27 | |||||||||||||
| タイトル | ||||||||||||||
| 言語 | ja | |||||||||||||
| タイトル | Effects of gas escape and crystallization on the complexity of conduit flow dynamics during lava dome eruptions | |||||||||||||
| タイトル | ||||||||||||||
| 言語 | en | |||||||||||||
| タイトル | Effects of gas escape and crystallization on the complexity of conduit flow dynamics during lava dome eruptions | |||||||||||||
| 言語 | ||||||||||||||
| 言語 | eng | |||||||||||||
| 著者 |
T. Kozono
× T. Kozono
× T. Koyaguchi
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| 抄録 | ||||||||||||||
| 内容記述タイプ | Other | |||||||||||||
| 内容記述 | We investigated the coupled effects of gas escape and crystallization on the dynamics of lava dome eruptions using a one-dimensional conduit flow model. The relationship between chamber pressure p(ch) and mass flow rate q for steady conduit flow commonly has a regime of negative differential resistance (i.e., dp(ch)/d(q) < 0), which causes a transition from lava dome to explosive eruption. Two positive-feedback mechanisms that result in negative differential resistance have been identified. First, effective magma viscosity decreases with increasing q because of a delay of crystallization, leading to reduced viscous wall friction (feedback 1). Second, magma porosity increases with increasing q because of less efficient gas escape, leading to reduced gravitational load (feedback 2). For high-phenocryst-content magma (volume fraction >0.5), feedback 1 is the main mechanism that forms negative differential resistance. In this case, the transition from lava dome to explosive eruption occurs when the magma supply rate exceeds a fixed critical value. For low-phenocryst-content magma (volume fraction <0.5), feedback 2 plays a key role so that the transition is controlled by the permeability of the surrounding rocks; the critical magma supply rate remarkably decreases with decreasing permeability. Transition due to feedback 2 is associated with a change in the chemical composition of volcanic gas, a drastic increase in magma porosity from nearly 0 to greater than 0.8, and overpressure at a shallower level, which can be detected from geochemical and geophysical field observations. | |||||||||||||
| 言語 | en | |||||||||||||
| 書誌情報 |
en : Journal of Geophysical Research: Solid Earth 巻 117, p. B08204, 発行日 2012-08 |
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| 言語 | en | |||||||||||||
| 出版者 | AMER GEOPHYSICAL UNION | |||||||||||||
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| 収録物識別子タイプ | EISSN | |||||||||||||
| 収録物識別子 | 2169-9356 | |||||||||||||
| DOI | ||||||||||||||
| 関連識別子 | 10.1029/2012JB009343 | |||||||||||||
