Abstract
A number of electric and magnetic signals have been observed on La Fournaise volcano, which are attributed to electrokinetic effects induced by the heavy rains which fall in this area. A general modeling of the flow in the unsaturated and saturated zones is proposed for an arbitrary topography, arbitrary spatial distributions of physical properties, and arbitrary rains. This flow generates an electrical field and an associated current which itself induces a variable magnetic field. Variations of water masses inside the volcano are also determined to predict gravity variations. Saturation, electric, magnetic, and gravity fields are given and discussed for various rain distributions including real ones.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Adler P.M.: Macroscopic electroosmotic coupling cœfficient in random porous media. Math. Geol. 33, 63 (2001)
Adler P.M., Le Mouel J.-L., Zlotnicki J.: Electrokinitic and magnetic fields generated by flow through a fractured zone: a sensitivity study or LA Fournaise Volcano. Geophys. Res. Lett. 26, 795–798 (1999)
Bonvalot S., Diament M., Gabalda G.: Continuous gravity recording with Scintrex CG-3M meters: a promising tool for monitoring active zones. Geophys. J. Int. 135, 470 (1998)
Fitterman D.V.: Electrokinetic and magnetic anomalies associated with dilatant regions in a layered earth. J. Geophys. Res. 83, 5923–5928 (1978)
Fitterman D.V.: Calculations of self-potential anomalies near vertical contacts. Geophysics 44, 195–205 (1979)
Ishido T., Pritchett J.W.: Numerical simulation of electrokinetic potentials associated with subsurface fluid flow. J. Geophys. Res. 104, 15247–15259 (1999)
Johnston M.J.S.: Review of electric and magnetic fields accompanying seismic and volcanic activity. Surv. Geophys. 18, 441–475 (1997)
Michel, S., Zlotnicki, J.: Self-potential and magnetic surveying of La Fournaise volcano (Réunion Island): correlations with faulting, fluid circulation, and eruption. J. Geophys. Res. B103, 17,845–17,857 (1998)
Mizutani H., Ishido T.: A new interpretation of magnetic field variation associated with the Matsushiro earthquakes. J. Geomagn. Geoelectr. 28, 179–188 (1976)
van Genuchten M.T.: A closed form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892–898 (1980)
Violette S., Ledoux E., Gablet P., Carbonnel J.-P.: Hydrologic and thermal modeling of an active volcano: the Piton de la Fournaise, Réunion. J. Hydrol. 191, 37–63 (1997)
Zlotnicki J., Le Mouel J.-L.: Possible electrokinetic origin of large magnetic variations at La Fournaise volcano. Nature 343, 633–635 (1990)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Adler, P.M., Thovert, JF. Under the Volcano: Unsaturated Flow and Induced Variations of Electromagnetic and Gravitational Fields. Transp Porous Med 83, 219–232 (2010). https://doi.org/10.1007/s11242-009-9471-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11242-009-9471-5