Radio Direction Finding Method to Mitigate Tsunami Risk in Sierra Leone

Abstract

In this study, the Radio Direction Finding method is proposed for the detection of electromagnetic signals, in the VLF band, to try to anticipate the occurrence of potentially destructive geophysical events. The experimentation concerns the interception of electromagnetic anomalies in Sierra Leone, in the five-day time window, associated with seismic events that could potentially generate tsunamis. The area of investigation is Sierra Leone, whose coastline is subjected to tidal wave hazards triggered by earthquakes generated in the Mid-Atlantic Ridge. Although Sierra Leone is not affected by recurrent earthquakes, there is nevertheless a low probability, estimated at 2 percent, of the occurrence of destructive earthquakes in the next 50 years. Also in estimates, the risk of rogue and potentially damaging waves is estimated to strike the Sierra Leone coast at least once in the next 10 years. The Radio Direction Finding experiment carried out continuously 24/7, has shown a close relationship between increased radio-anomalies, in the frequencies of 6,000 Hz, a time window between electromagnetic anomaly detection and the imminence of an earthquake, and higher frequency times for the risk of earthquake occurrence in the Mid-Atlantic Ridge.