Three-dimensional electrical resistivity model of the hydrothermal system in Long Valley Caldera, California, from magnetotellurics

2016 ◽  
Vol 43 (15) ◽  
pp. 7953-7962 ◽  
Author(s):  
J. R. Peacock ◽  
M. T. Mangan ◽  
D. McPhee ◽  
P. E. Wannamaker
Keyword(s):  
Electrical Resistivity ◽  
Hydrothermal System ◽  
Three Dimensional ◽  
Long Valley Caldera ◽  
Long Valley ◽  
Resistivity Model

scholarly journals Mapping Water and Heat Deep Under Long Valley Caldera

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Leah Crane
Keyword(s):  
Electrical Resistivity ◽  
Heat Source ◽  
Hydrothermal System ◽  
Long Valley Caldera ◽  
Long Valley

Researchers use electrical resistivity to find the heat source and reservoir feeding Long Valley Caldera's labyrinthine hydrothermal system.

scholarly journals Magma reservoir beneath Azumayama Volcano, NE Japan, as inferred from a three-dimensional electrical resistivity model explored by means of magnetotelluric method

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Masahiro Ichiki ◽  
Toshiki Kaida ◽  
Takashi Nakayama ◽  
Satoshi Miura ◽  
Mare Yamamoto ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Confidence Interval ◽  
Hydrothermal Fluid ◽  
Volume Fraction ◽  
Source Region ◽  
Three Dimensional ◽  
Magma Reservoir ◽  
Resistivity Model ◽  
Magnetotelluric Method ◽  
Ne Japan

AbstractAn electrical resistivity model beneath Azumayama Volcano, NE Japan, is explored using magnetotelluric method to probe the magma/hydrothermal fluid distribution. Azumayama is one of the most concerning active volcanoes capable of producing a potential eruption triggered by the 2011 Tohoku-Oki Earthquake. The three-dimensional resistivity model reveals a conductive magma reservoir (< 3 Ωm) at depths of 3–15 km below sea level (bsl). The 67% and 90% confidence intervals of resistivity are 0.2–5 Ωm and 0.02–70 Ωm, respectively, for the magma reservoir. We assumed dacitic melt + rock at a shallow depth of 4 km bsl and andesitic melt + rock at a greater depth of 9 km bsl. The confidence interval of resistivity cannot be explained by using dacitic melt + rock condition at a depth of 4 km bsl. This suggests that very conductive hydrothermal fluids coexist with dacitic melt and rock in the shallow part of the magma reservoir. For the depth of 9 km bsl, the 67% confidence interval of resistivity is interpreted as water-saturated (8.0 weight %) andesitic melt–mafic rock complex with melt volume fractions greater than 4 volume %, while the shear wave velocity requires the fluid and/or melt volume fraction of 6–7 volume % at that depth. Considering the fluid and/or melt volume fraction of 6–7 volume %, the conductive hydrous phase is likewise required to explain the wide range of the 67% confidence interval of resistivity. The Mogi inflation source determined from geodetic data lies on the resistive side near the top boundary of the conductive magma reservoir at a depth of 2.7 or 3.7 km bsl. Assuming that the resistivity of the inflation source region is above the upper bound of the confidence interval of resistivity for the conductive magma reservoir and that the source region is composed of hydrothermal fluid + rock, the resistivity of the source region is explained by a hydrothermal fluid volume fraction below 5 volume %, which is the percolation threshold porosity in an effusive eruption. This indicates that the percolation threshold characterizes the inflation source region.

scholarly journals Deep Electrical Resistivity Tomography for a 3D picture of the most active sector of Campi Flegrei caldera

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. Troiano ◽  
R. Isaia ◽  
M. G. Di Giuseppe ◽  
F. D. A. Tramparulo ◽  
S. Vitale
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Three Dimensional ◽  
Campi Flegrei ◽  
Gaseous Emissions ◽  
Resistivity Tomography ◽  
Tectonic Reconstruction ◽  
Resistivity Model ◽  
Fumarole Field ◽  
First Time

Abstract The central sector of the Campi Flegrei volcano, including the Solfatara maar and Pisciarelli fumarole field, is currently the most active area of the caldera as regards seismicity and gaseous emissions and it plays a significant role in the ongoing unrest. However, a general volcano-tectonic reconstruction of the entire sector is still missing. This work aims to depict, for the first time, the architecture of the area through the application of deep Electrical Resistivity Tomography. We reconstructed a three-dimensional resistivity model for the entire sector. Results provide useful elements to understand the present state of the system and the possible evolution of the volcanic activity and shed solid bases for any attempt to develop physical-mathematical models investigating the ongoing phenomena.

scholarly journals The hydrothermal system of Long Valley Caldera, California

1977 ◽  
Author(s):  
M.L. Sorey ◽  
Robert Edward Lewis ◽  
F.H. Olmsted
Keyword(s):  
Hydrothermal System ◽  
Long Valley Caldera ◽  
Long Valley
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