Magnetotelluric imaging of crustal magma storage beneath the Mesozoic crystalline mountains in a nonvolcanic region, northeast Japan

Umeda, Koji; Asamori, Koichi; Negi, Tateyuki; Ogawa, Yasuo

doi:10.1029/2006gc001247

Cited by 9 publications

(12 citation statements)

References 27 publications

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“…The distribution of conductor C6 and its resistivity (1 to 10 Ωm) are also consistent with the results of previous studies (Ogawa et al 1986;Ogawa 1987b). Recent wideband magnetotelluric profile measurements with site spacings of several kilometers have yielded more detailed images of the locations and depths of these conductors, although those images were limited to two-dimensions (Mitsuhata et al 2001;Ogawa et al 2001;Umeda et al 2006;Mishina 2009;Asamori et al 2010;Ichihara et al 2011).…”

Section: Resultssupporting

confidence: 78%

Three-dimensional electromagnetic imaging of fluids and melts beneath the NE Japan arc revisited by using geomagnetic transfer function data

Kanda

Ogawa

2014

Earth Planet Sp

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The three-dimensional distribution of fluids and melts under the NE Japan arc was imaged using its resistivity structure, modeled with geomagnetic transfer functions. The data were collected at 37 stations located on a 20-km grid, at periods ranging from 16 to 256 s. In spite of the narrow period band nature, these periods turn out to be sensitive to conductors in the deep crust and upper mantle. The geomagnetic transfer functions represent lateral resistivity variations, which yield inherently nonunique model results when using the geomagnetic transfer functions alone. However, by fixing the resistivity structure of the surrounding seawater distribution, the intrinsic nonuniqueness is alleviated. In this study, we show an inversion result using a 100-Ωm uniform Earth with fixed resistivity of surrounding oceans. As a result, it was found that the features of the short period transfer function require shallow conductors in the upper crust, which is suggested to represent the northern Tohoku conducting belt of a previous study. The final model is characterized by a highly conductive zone along the quaternary volcanic arc in the depth range of the lower crust to the upper mantle. The conductor, which is obtained mainly from the features of longer-period data, is particularly clear beneath the Sengan geothermal area. The deep crustal conductor implies the existence of partial melt and/or high-salinity fluids.

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Section: Resultssupporting

confidence: 78%

Three-dimensional electromagnetic imaging of fluids and melts beneath the NE Japan arc revisited by using geomagnetic transfer function data

Kanda

Ogawa

2014

Earth Planet Sp

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“…As underlined in Figure 7, the presence at shallow depths of the high conductive brine is probably responsible for a screen effect that makes detection of deeper conductive bodies difficult. Deep anomalies below a superficial conductive layer are detectable by the MT method in volcanic contexts [e.g., Whaler and Hautot , 2006; Umeda et al , 2006]. However, their detectability requires a large volume (several tens of km 3 ) of very conductive magma ( ρ < 10 ohm.m).…”

Section: Discussionmentioning

confidence: 99%

“…Deep anomalies below a superficial conductive layer are detectable by the MT method in volcanic contexts [e.g., Whaler and Hautot, 2006;Umeda et al, 2006]. However, their detectability requires a large volume (several tens of km 3 ) of very conductive magma (r < 10 ohm.m).…”

Section: Possible Deep (>3-4 Km) Magmamentioning

confidence: 99%

A new petrological and geophysical investigation of the present‐day plumbing system of Mount Vesuvius

Pommier¹,

Tarits

Hautot

et al. 2010

Geochem Geophys Geosyst

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[1] A model of the electrical resistivity of Mt. Vesuvius has been elaborated to investigate the present structure of the volcanic edifice. The model is based on electrical conductivity measurements in the laboratory, on geophysical information, in particular, magnetotelluric (MT) data, and on petrological and geochemical constraints. Both 1-D and 3-D simulations explored the effect of depth, volume and resistivity of either one or two reservoirs in the structure. For each configuration tested, modeled MT transfer functions were compared to field transfer functions from field magnetotelluric studies. The field electrical data are reproduced with a shallow and very conductive layer (∼0.5 km depth, 1.2 km thick, 5 ohm.m resistive) that most likely corresponds to a saline brine present beneath the volcano. Our results are also compatible with the presence of cooling magma batches at shallow depths (<3-4 km depth). The presence of a deeper body at ∼8 km depth, as suggested by seismic studies, is consistent with the observed field transfer functions if such a body has an electrical resistivity > ∼100 ohm.m. According to a petro-physical conductivity model, such a resistivity value is in agreement either with a low-temperature, crystal-rich magma chamber or with a small quantity of hotter magma interconnected in the resistive surrounding carbonates. However, the low quality of MT field data at long periods prevent from placing strong constraints on a potential deep magma reservoir. A comparison with seismic velocity values tends to support the second hypothesis. Our findings would be consistent with a deep structure (8-10 km depth) made of a tephriphonolitic magma at 1000°C, containing 3.5 wt%H 2 O, 30 vol.% crystals, and interconnected in carbonates in proportions ∼45% melt −55% carbonates.

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“…Another approach could be the combined use of geophysical (magnetotelluric and seismic interpretations) and petrologic (geothermobarometric constrains on the depth and nature of the magma chamber) methods (Pommier et al, 2010b). The perspective of the magnetotelluric studies was underlined by Umeda et al (2006) who indicated a crustal magma storage beneath the Iide Mts, Japan that was previously considered as a non-volcanic region.…”

Section: Introductionmentioning

confidence: 99%

Combined magnetotelluric and petrologic constrains for the nature of the magma storage system beneath the Late Pleistocene Ciomadul volcano (SE Carpathians)

Harangi

Novák

Kiss

et al. 2015

Journal of Volcanology and Geothermal Research

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Magnetotelluric imaging of crustal magma storage beneath the Mesozoic crystalline mountains in a nonvolcanic region, northeast Japan

Cited by 9 publications

References 27 publications

Three-dimensional electromagnetic imaging of fluids and melts beneath the NE Japan arc revisited by using geomagnetic transfer function data

Three-dimensional electromagnetic imaging of fluids and melts beneath the NE Japan arc revisited by using geomagnetic transfer function data

A new petrological and geophysical investigation of the present‐day plumbing system of Mount Vesuvius

Combined magnetotelluric and petrologic constrains for the nature of the magma storage system beneath the Late Pleistocene Ciomadul volcano (SE Carpathians)

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