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Shallow structure of Los Humeros (LH) caldera and geothermal reservoir from magnetotellurics and potential field data
- Source :
- Geophysical journal international, 223 (2020): 666–675. doi:10.1093/gji/ggaa338, info:cnr-pdr/source/autori:Corbo-Camargo, Fernando; Arzate, Jorge; Fregoso, Emilia; Norini, Gianluca; Carrasco-Núñez, Gerardo; Yutsis, Vsevolod; Herrera, Juan; Hernández, Javier/titolo:Shallow structure of Los Humeros (LH) caldera and geothermal reservoir from magnetotellurics and potential field data/doi:10.1093%2Fgji%2Fggaa338/rivista:Geophysical journal international (Print)/anno:2020/pagina_da:666/pagina_a:675/intervallo_pagine:666–675/volume:223
- Publication Year :
- 2020
- Publisher :
- Oxford University Press (OUP), 2020.
-
Abstract
- SUMMARYThis study focuses in the analysis of the internal structure of the upper 3 km of Los Humeros (LH) caldera and the relation of electrical and hydrothermal anomalies. For this purpose, we measured, processed and interpreted 78 broad-band magnetotelluric (MT) soundings. We performed a 3-D inversion of the data set (ModEM) using all MT soundings, although only half of the available frequencies per sounding due to limited computed power. We also carried out the 2-D inversions (NLCG) of the invariant determinant along two orthogonal profiles (EW and NS) crossing the caldera structure; their comparison yields similar resistivity and structural models results. The resistivity modelling is complemented with the results of a joint 3-D inversion of an accurate gravity database of 720 stations, and total field aeromagnetic data (SGM) from the caldera crater. The combined results provide novel details about the structure of the shallow geothermal reservoir of the resurgence caldera complex hosting the active hydrothermal system. Density and resistivity models show the existence of a composed crater basin structure separated by an EW high-density structure; the northern basin is associated to the LH crater, whereas the southern basin associates to the emergent Los Potreros (LP) caldera basin. The magnetization model indicates that there is a common source for the magnetic volcanic products observed at the caldera surface, and that the LP fault is the more magnetized fault of the geothermal system. The propylic zoning under the geothermal field, which according to the MT model results has resistivities above ∼100 Ω-m, was extrapolated using this and additional criteria to obtain the distribution of other hypothetical propylitic zones of hydrothermal potential.
- Subjects :
- Gravity anomalies and Earth structure
Magnetic anomalies: modelling and interpretation
010504 meteorology & atmospheric sciences
Joint inversion
Calderas
Geothermal reservoir
Potential field
010502 geochemistry & geophysics
01 natural sciences
Hydrothermal systems
Geophysics
Magnetotellurics
Geochemistry and Petrology
Caldera
Petrology
Geology
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 1365246X and 0956540X
- Volume :
- 223
- Database :
- OpenAIRE
- Journal :
- Geophysical Journal International
- Accession number :
- edsair.doi.dedup.....c6bcc1232215a04b97d0a81492d318aa