This preprint is under consideration at Earth, Planets and Space. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Full paper
Magma Reservoir Beneath Azumayama Volcano, NE Japan as Inferred from Three-dimensional Electrical Resistivity Image by Magnetotellurics
Masahiro Ichiki
Graduate School of Science, Tohoku University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0814-1265
License:
This work is licensed under a CC BY 4.0 License. Read Full License
An electrical resistivity image beneath Azumayama Volcano, NE Japan is modeled using magnetotellurics to probe the magma/hydrothermal fluid distribution. The 3-D inversion modeling images the conductive magma reservoir beneath Oana crater at depths of 3–15 km. The resolution scale for the conductor is 5 km by checkerboard resolution tests and the 67 % and 90 % confidential intervals of resistivity are 0.2–5 Ωm and 0.02–70 Ωm, respectively, for the region of less than 3 Ωm resistivity. The shallower part of the conductor is not explained by a water-saturated (5.5 wt %) dacitic melt, and the more probable interpretation is that it consists of a water-saturated, dacitic melt-silicic rock-hydrothermal fluid complex. The deeper part of the conductor is interpreted as a water-saturated (8 wt %) andesitic melt-mafic rock complex. The Mogi inflation source determined from GNSS and tilt data is located near the top boundary of the conductor at a depth of 2.7–3.7 km, which suggests that the ascent of hydrothermal fluids exsolved from the dacitic melt is interrupted by the impermeable wall and conduit. Assuming two phases of hydrothermal fluid and silicic rock, the resistivity at the inflation source, regarded as the upper bound resistivity of the conductor, is realized by the hydrothermal fluid fraction below the percolation threshold porosity in an effusive eruption. This indicates that the percolation threshold porosity in an effusive eruption characterizes the impermeable wall and conduit associated with the Mogi inflation source.
Keywords
magnetotellurics, electrical resistivity, electrical conductivity, magma reservoir, melt fraction, permeability, percolation threshold, change point, hydrothermal fluid, Mogi source
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the latest manuscript can be downloaded and accessed as a PDF.
This is a list of supplementary files associated with this preprint. Click to download.
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 07 Jan, 2021
No community comments so far
Reviewer #2 agreed
On 03 Jan, 2021
Review #1 received
Received 02 Jan, 2021
Reviewer #1 agreed
On 01 Jan, 2021
Editor assigned
On 30 Dec, 2020
Reviewers invited
Invitations sent on 30 Dec, 2020
Submission checks complete
On 30 Dec, 2020
Editor invited
On 30 Dec, 2020
First submitted
On 28 Dec, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Learn more about our company.
This preprint is under consideration at Earth, Planets and Space. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Full paper
Magma Reservoir Beneath Azumayama Volcano, NE Japan as Inferred from Three-dimensional Electrical Resistivity Image by Magnetotellurics
Masahiro Ichiki
Graduate School of Science, Tohoku University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0814-1265
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 07 Jan, 2021
No community comments so far
Reviewer #2 agreed
On 03 Jan, 2021
Review #1 received
Received 02 Jan, 2021
Reviewer #1 agreed
On 01 Jan, 2021
Editor assigned
On 30 Dec, 2020
Reviewers invited
Invitations sent on 30 Dec, 2020
Submission checks complete
On 30 Dec, 2020
Editor invited
On 30 Dec, 2020
First submitted
On 28 Dec, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
An electrical resistivity image beneath Azumayama Volcano, NE Japan is modeled using magnetotellurics to probe the magma/hydrothermal fluid distribution. The 3-D inversion modeling images the conductive magma reservoir beneath Oana crater at depths of 3–15 km. The resolution scale for the conductor is 5 km by checkerboard resolution tests and the 67 % and 90 % confidential intervals of resistivity are 0.2–5 Ωm and 0.02–70 Ωm, respectively, for the region of less than 3 Ωm resistivity. The shallower part of the conductor is not explained by a water-saturated (5.5 wt %) dacitic melt, and the more probable interpretation is that it consists of a water-saturated, dacitic melt-silicic rock-hydrothermal fluid complex. The deeper part of the conductor is interpreted as a water-saturated (8 wt %) andesitic melt-mafic rock complex. The Mogi inflation source determined from GNSS and tilt data is located near the top boundary of the conductor at a depth of 2.7–3.7 km, which suggests that the ascent of hydrothermal fluids exsolved from the dacitic melt is interrupted by the impermeable wall and conduit. Assuming two phases of hydrothermal fluid and silicic rock, the resistivity at the inflation source, regarded as the upper bound resistivity of the conductor, is realized by the hydrothermal fluid fraction below the percolation threshold porosity in an effusive eruption. This indicates that the percolation threshold porosity in an effusive eruption characterizes the impermeable wall and conduit associated with the Mogi inflation source.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the latest manuscript can be downloaded and accessed as a PDF.