Combined TEM-MT investigation of shallow-depth resistivity structure of Mt Somma-Vesuvius

Manzella, Adele; Volpi, Gianni; Zaja, A.; Meju, Max A.

doi:10.1016/s0377-0273(03)00313-5

Cited by 39 publications

(58 citation statements)

References 32 publications

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“…Such an anomaly has also been detected by the MT study of Di Maio et al [1998]. However, based on combined time domain electromagnetic and magnetotelluric soundings (TDEM‐MT investigation), Manzella et al [2004] argue that the conductive anomaly detected below Mt. Vesuvius corresponds to a superficial brine layer rather than to the presence of a deep conductive magma body.…”

Section: Introductionmentioning

confidence: 94%

“…A few magnetotelluric studies have been conducted on Mt. Vesuvius [ Di Maio et al , 1998; Müller et al , 1999; Manzella et al , 2004; Troiano et al , 2008]. These investigations have provided MT transfer functions at a series of sites on the volcano (Figure 2) presented in form of apparent resistivity and MT impedance phase as a function of the frequency, or the period.…”

Section: Laboratory and Field Electrical Studies Applied To Mount Vesmentioning

confidence: 99%

“…These data express the complex electromagnetic induced response of the Earth to the fluctuations of the natural electromagnetic field, which is a function of the distribution of electrical resistivity in the substratum [e.g., Simpson and Bahr , 2005]. Apparent resistivities are shown in the studies from Di Maio et al [1998] and Manzella et al [2004]. Only Manzella et al [2004] show phase data.…”

Section: Laboratory and Field Electrical Studies Applied To Mount Vesmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 94%

Section: Laboratory and Field Electrical Studies Applied To Mount Vesmentioning

confidence: 99%

Section: Laboratory and Field Electrical Studies Applied To Mount Vesmentioning

confidence: 99%

See 1 more Smart Citation

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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“…We use natural electromagnetic fields in the frequency range between 10 KHz and 1 Hz. Electromagnetic methods are widely used for the imaging of active volcanoes because the resistivity is sensitive to the fluids and the clay alteration minerals (Ogawa and Takakura, 1990;Ogawa et al, 1992Ogawa et al, , 1998Ogawa et al, , 1999Pellerin et al, 1996;Di Maio et al, 1998;Kagiyama et al, 1999;Fuji-ta et al, 1999;Matsushima et al, 2001;Müller and Haak, 2004;Ç aglar andİşseven, 2004;Manzella et al, 2004;Oskooi et al, 2005;Aizawa et al, 2005). It must be noted, however, that the interpretation of the conductors as either fluids or clay minerals can lead to opposing conclusions on the hydrology because fluids require high permeability whereas clay alterations may imply low permeability.…”

Section: Introductionmentioning

confidence: 99%

Two electrical conductors beneath Kusatsu-Shirane volcano, Japan, imaged by audiomagnetotellurics, and their implications for the hydrothermal system

et al. 2006

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Kusatsu-Shirane volcano, Japan, is known for its active phreatic eruptions. We have investigated its hydrothermal system by conducting audio-magnetotelluric soundings at 22 stations along a profile that extends across the volcano. The final two-dimensional model is characterized by two conductors. One is a 300-to 1000-m-thick conductor of 1-10 m, which is located on the eastern slope and covered with 200-m-thick resistive layers of Kusatsu-Shirane lava and pyroclastics. This conductor indicates the presence of a Montmorillonite-rich layer of Pliocene volcanic rocks that may function both as an impermeable floor for the shallow fluid path from the peak to the hot springs to the east and as an impermeable cap for the deeper fluid path from the summit region to the foot of the volcano. The second conductor is found at a depth of 1-2 km from the surface, at the peak of the volcano, and its resistivity is as low as 1 m or less. This low resistivity can be explained by fluids containing high concentrations of chloride and sulfate which were supplied from the magmatic gases. Micro-earthquakes cluster above this conductor, and the cut-off of the earthquakes corresponds to the top of the conductor. This conductor infers the presence of the fluid reservoir, and the upward release of these fluids from the reservoir through the conduit presumably triggers the micro-earthquakes at the peak area of the volcano. Crustal deformation modeling using GPS and leveling data of the past 10 years revealed that the center of the deflation coincides with the top of the second conductor, indicating that the fluid reservoir itself can be hosting the deformation.

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“…Magnetotelluric (MT) and audio-magnetotelluric (AMT) surveys at volcanoes areas have displayed conductors at different depth associated with hydrothermal fluid circulation, clay and/or with partial melting (Ingham, 1992;Kagiyama et al, 1999;Jones and Dumas, 1993;Schnegg, 1997;Ritter et al, 1998;Matsushima et al, 2001;Harinarayana et al, 2004;Müller and Haak, 2004). Long-offset transient electromagnetic (LOTEM) surveys have been used in deep research (Commer et al, 2005;Müller et al, 2002) while collocated time-domain electromagnetic (TDEM) and MT soundings were used in shallow research (Manzella et al, 2004). The results obtained from an AMT survey carried out in Terceira Island (Azores) are presented and discussed in this paper.…”

Section: Introductionmentioning

confidence: 99%

An audio-magnetotelluric investigation in Terceira Island (Azores)

Santos

Trota

Soares

et al. 2006

Journal of Applied Geophysics

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Combined TEM-MT investigation of shallow-depth resistivity structure of Mt Somma-Vesuvius

Cited by 39 publications

References 32 publications

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

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

Two electrical conductors beneath Kusatsu-Shirane volcano, Japan, imaged by audiomagnetotellurics, and their implications for the hydrothermal system

An audio-magnetotelluric investigation in Terceira Island (Azores)

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