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.

Radio signals originating from natural and artificial (anthropogenic) sources were captured by our stationary and mobile monitoring very low frequency (VLF) radio stations. These signals were classified and divided into groups according to their source. Capturing of natural origin signals and their spectral patterns together with the time of their origin seem to confirm our assumption about the correlation between deformations in the slope and electromagnetic (EM) anomalies in the radio spectrum after further analysis. We conclude that since we always observe them a few days to hours after heavy rainfall and they are not observed at both stations at the same time, it confirms that they represent local phenomena not caused by atmospheric or ionospheric processes or events but deformation in landslide body microfracturation and microdisplacements via piezo-electromagnetic effect. Also, at the time after capture, it is possible to observe changes in the terrain in the form of new cracks of a sub-meter size. The EM field around the VLF band, DC – 30 kHz (up to 24 kHz in our measurement) was recorded using sound cards that served as an AD/DA converter. The VLF monitoring station and mobile measurements were located on the landslide slopes.