Electric effects induced by artificial seismic sources at Somma-Vesuvius volcano

Rosa Di Maio Rosa Di Maio,Gianpaolo Cecere Gianpaolo Cecere,Ester Piegari Ester Piegari,Prospero De Martino Prospero De Martino

doi:10.4401/ag-6451

Rosa Di Maio Rosa Di Maio, Gianpaolo Cecere Gianpaolo Cecere + Show 2 more

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https://doi.org/10.4401/ag-6451

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Abstract

<p>In this paper, we present a series of self-potential measurements at Somma-Vesuvius volcanic area acquired in conjunction with an active seismic tomography survey. The aim of our study is both to provide further confirmation to the occurrence of seismo-electric coupling and to identify sites suitable for self-potential signal monitoring at Somma-Vesuvius district. The data, which were collected along two perpendicular dipoles, show significant changes on the natural electric field pattern. These variations, attributable to electrokinetic processes triggered by the artificial seismic waves, were observed after explosions occurred at a distance less than 5 km from the SP dipole arrays. In particular, we found that the NW-SE component of the natural electric field was more sensible to the shots than the NE-SW one, and the major effects did not correspond to the nearest shots. Such evidences were interpreted considering the underground electrical properties as deduced by previous detailed resistivity and self-potential surveys performed in the study area.</p>

Highlights

The self-potential (SP) geophysical method consists on measurement at the ground surface of anomalous potential drops at the ends of a passive line in which impolarizable electrodes are grounded
Many theoretical and experimental studies on physical mechanisms responsible for seismo- or volcano-electromagnetic effects have been presented [e.g., Nur 1972, Mizutani et al 1976, Sill 1983, Varotsos and Alexopoulos 1984a,b, Johnston 1989, Fujinawa and Takahashi 1990, Di Maio and Patella 1991, Fujinawa and Takahashi 1992, Di Maio and Patella 1994, Pride 1994, Patella et al 1997, Revil et al 1999a,b, Uyeda et al 2000, Garambois and Dietrich 2001, Garambois and Dietrich 2002, Garambois et al 2002, Varotsos 2005], most authors agree that the electrokinetic phenomenon, called streaming potential, is the most likely source for the ultra-long period seismo-electric signals considered in this paper
We present a series of self-potential measurements at Somma-Vesuvius volcanic area (Campania Region, Italy) performed in conjunction with artificial shots fired for active seismic experiments in the framework of the Mt

Summary

Introduction

The self-potential (SP) geophysical method consists on measurement at the ground surface of anomalous potential drops at the ends of a passive line in which impolarizable electrodes are grounded. Many theoretical and experimental studies on physical mechanisms responsible for seismo- or volcano-electromagnetic effects have been presented [e.g., Nur 1972, Mizutani et al 1976, Sill 1983, Varotsos and Alexopoulos 1984a,b, Johnston 1989, Fujinawa and Takahashi 1990, Di Maio and Patella 1991, Fujinawa and Takahashi 1992, Di Maio and Patella 1994, Pride 1994, Patella et al 1997, Revil et al 1999a,b, Uyeda et al 2000, Garambois and Dietrich 2001, Garambois and Dietrich 2002, Garambois et al 2002, Varotsos 2005], most authors agree that the electrokinetic phenomenon, called streaming potential, is the most likely source for the ultra-long period seismo-electric signals considered in this paper Such a phenomenon is substantially caused by the electric double layer on the interface between solid and fluid in a fluid-saturated porous rock [e.g., Overbeek 1952, Keller and Frisch-knecht 1966, Mizutani et al 1976, Morgan et al 1989, Pride 1994]. This relative movement of cations with respect to the firmly attached anions generates an electric current and the socalled streaming potential

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