Induced polarization effects comparison for galvanic and induction installations in transient electromagnetic methods
The purpose of the work is to compare the anomalous responses from the IP-effects in transient electromagnetic methods for galvanic and induction installations. By a galvanic installation is meant one using a horizontal electric line in a "line-line" configuration, and by an induction installation, one using ungrounded contours in a "loop-loop" configuration. Registering the fast decaying induction-induced polarization (IIP) that occurs in the geo-environment in the presence of polarized objects, makes it possible to avoid false electrical resistivity anomalies and to find polarizability anomalies. The comparison is realized using numerical modeling within the one-dimensional model with a frequency dispersion of electrical resistivity (described by the Cole-Cole formula). The modeling has shown that the anomalous IP-effect for the galvanic installation is higher than the IIP effect for the induction installation. The IP effect contribution virtually does not decay with time, as opposed to the IIP effect.