A VLF survey using current gathering phenomena for tracing buried faults of Fethiye–Burdur Fault Zone, Turkey

Two-dimensional resistivity imaging in the Kestelek boron area by VLF and DC resistivity methods

“…The direction of horizontal electric field for used radio station is approximately perpendicular to boron deposits, so the observed VLF responses for this profile are close to the TM mode and strong VLF resistivity and especially phase responses can be expected (Fischer et al, 1983;Gürer et al, 2009). Very high VLF resistivity and phase responses in H-polarization mode also can be enhanced by very high resistivity contrast between resistors and surrounding medium (Fischer et al, 1983;Gürer et al, 2009). Very high phase values (>45°) also may indicate that the thickness of conductive layer is bigger than the penetration depth of the VLF signals.…”

“…Thus, this filter technique provides relative current density (I a ) pseudosections which are derived from the real part of VLF tipper data at consecutive stations (H − 3 , H − 2 , etc.). The filter can be calculated as: where Δz is the assumed thickness of the current sheet, Δx is the distance between the data points and also the depth to the current sheet, location of the calculated current density is beneath the center point of the six data points (Gürer et al, 2009;Karous and Hjelt, 1983). The filtered VLF tipper data can provide the interpreter with a useful standing point for numerical modelling.…”

“…The direction of VLF horizontal electric field (23.4 kHz, Germany) for this profile is approximately perpendicular to the boron deposits describing the H-polarization mode. Fischer et al (1983) and Gürer et al (2009) reported that, VLF resistivity and phase become stronger in H-polarization mode in the presence of high resistivity contrast with the adjacent or lower layers. So we can expect strong VLF resistivity and phase responses in transverse magnetic (TM) mode.…”

Landform characterization using geophysics—Recent advances, applications, and emerging tools

“…Beylich et al (2004) used RMT in combination with water discharge and water chemistry data to characterize regolith thickness in a study of chemical denudation in an arctic-alpine drainage basin. VLF was used to characterize the internal structure of a mud volcano (Lin and Jeng, 2010) and for the study of faults (Gürer et al, 2009). …”

The VLF-EM imaging of potential collapse on the LUSI embankment

“…Thus, VLF-EM was carried out on LUSI embankment. VLF-EM has been used extensively in some cases where horizontal anomaly occurred (Gürer et al, 2009;Jeng et al, 2007;Lin and Jeng, 2010) but this method is very rarely used to identify embankment failures. In addition, VLF-EM instrument is particularly useful for carrying out shallow survey in urban environments and in LUSI embankment due to its nondestructive nature and capability of providing appreciable resolution shallow subsurface profile.…”