Fabio Iván Zyserman is an Independent Researcher at CONICET (the National Scientific and Technical Research Council of Argentina) and an Associate Professor at the Facultad de Ciencias Astronómicas y Geofísicas of the Universidad Nacional de La Plata (UNLP). His core research interests lie at the intersection of numerical modeling, wave propagation, and electromagnetic methods in geophysics. Over the years, his work has focused on developing and applying computational tools to better understand subsurface processes. A significant part of his career has been dedicated to the theoretical and numerical study of coupled phenomena, particularly seismoelectric and electroseismic methods. With colleagues they have worked extensively on extending and applying Pride’s theory to model the conversion between seismic and electromagnetic energy in fluid-saturated porous media. This includes exploring its sensitivity to fluid properties like salinity, viscosity, and saturation, with applications ranging from hydrocarbon and gas hydrate exploration to groundwater and environmental contamination studies. Beyond seismoelectrics, the reasearch group he leads has also been actively involved in magnetotelluric modeling and inversion, as well as more recent applications such as muon radiography for volcano characterization and hydrological studies. A common thread throughout his work is the development of advanced numerical techniques—particularly finite element methods—to solve complex direct and inverse problems in geophysics.
In this talk I present an overview of our research in the geophysical methods based on the coupling between seismic waves and electromagnetic fields, a field known as seismoelectrics and its reciprocal phenomenon, electroseismics. The fundamental physical mechanism enabling this coupling is the so called electric double layer (EDL) that forms at the interface between a mineral grain (the solid matrix of a porous rock) and the electrolyte (the fluid saturating the pores). When a seismic wave propagates through a saturated porous medium, it induces a relative motion between the solid matrix and the pore fluid. This movement displaces the mobile ions in the diffuse layer, generating an electrical streaming current, phenomenon known as electrofiltration. The reverse process, where an applied external electric field causes the mobile ions to move, dragging the pore fluid and inducing a mechanical wave in the rock matrix, is termed electro-osmosis.
I’ll show the different type of signals appearing in this context, namely the one known as coseismic fields, and a second one, more significant for exploration, the interface response, which is an electromagnetic signal generated at a boundary where there is a contrast in physical or electrochemical properties (e.g., between different rock layers or between a saturated and an unsaturated zone). Unlike coseismic fields, the interface response is created at the interface and propagates away from it at the speed of light, arriving at surface detectors almost instantaneously and well before the slower seismic waves. This allows for the detection of subsurface interfaces with the temporal resolution of seismic methods but sensitive to contrasts in fluid properties. Beyond these two well-known signals, a third type of conversion is mentioned: the evanescent electromagnetic wave. This field is generated at interfaces and is characterized by an amplitude that decays rapidly with distance from the interface. Building upon these concepts, I’ll describe the behavior of these signals, and the information that can be extracted from them, when studying different geophysical targets, such as a glacial environment, gas hydrates reservoirs and partially saturated media employing both analytic and numerical methodologies. Further, I’ll present an extension of Pride’s theory, one of the presently prevalent ones, to partially saturated media. In this extension, a second EDL at the air/water interface is taken into account. This allows to explain laboratory measurements of non-monotonous streaming potential coefficients, something that has up to now been partially accomplished by adjusting empirical laws.
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