On potential use of natural electromagnetic emissions in ELF, VLF and HF radio bands at active landslide areas: Preliminary results from Vinohrady nad Váhom site (Slovakia)
The use of natural electromagnetic (EM) emissions in extreme low frequency (ELF) and very low frequency (VLF) radio bands for monitoring and predicting landslide activity is examined. The approach is based on measuring EM emissions using radio receivers and subsequent correlation of their intensity with the amount and character of deformation in the landslide. There are several sources of EM emissions in the rock environment, but it is mostly the piezoelectric impulse of quartz grains during the deformation or sliding movements within rock masses. Deformation was observed in the studied landslide body. Deformations were measured using a geodetic band and a network of stakes, which were installed before and re-measured after recording a natural EM signal attributed to the geodynamic activity. A method of direct monitoring of the entire VLF spectrum using sound cards such as AD converters was applied. So far, several candidate signals were captured and two permanent VLF monitoring stations have been built.