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Influence of seismic activity on the atmospheric electric field in Lisbon (Port...
Silva, H.G.; Oliveira, M.M.; Serrano, C.; Bezzeghoud, M.; Reis, A.H.; Rosa, R.N.; Biagi, F.In the present study, we considered the influence of seismic activity on the atmospheric electric field recorded at Portela meteorological station (Lisbon, Portugal) for the period from 1955 to 1991. To this end, an exploratory method was developed, which involved the selection of events for which the distance from the atmospheric electrical field sensor to the earthquake epicenter is smaller than the preparati...
Wavelet analysis of the LF radio signals collected by the European VLF/LF netwo...
Righetti, F.; Biagi, F.; Maggipinto, T.; Schiavulli, L.; Ligonzo, T.; Ermini, A.; Moldovan, I.A.; Moldovan, A.S.; Buyuksarac, A.; Silva, H.G.In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz) and LF (150-300 kHz) bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed throughout Europe to establish a ‘European VLF/LF Network’. At pr...
Anomalies Observed in VLF and LF Radio Signals on the Occasion of the Western T...
Biagi, F.; Righetti, F.; Maggipinto, T.; Schiavulli, L.; Ligonzo, T.; Ermini, A.; Moldovan, I.A.; Moldovan, A.S.; Silva, H.G.; Bezzeghoud, M.VLF radio signals lie in the 10 - 60 kHz frequency band. These radio signals are used for worldwide navigation support, time signals and for military purposes. They are propagated in the earth-ionosphere wave-guide mode along great circle propagation paths. So, their propaga-tion is strongly affected by the ionosphere conditions. LF signals lie in 150 - 300 kHz frequency band. They are used for long way broadca...
Influence of seismic activity in the atmospheric electrical field in Lisbon (Po...
Silva, Hugo; Serrano, Cláudia; Reis, Heitor; Bezzeghoud, Mourad; Rosa, Rui; Borges, José; Caldeira, Bento; Tlemçani, M.; Biagi, F.The atmospheric electric field (AEF) can be influenced by different factors like cosmic radiation, radioactivity and aerosols [1]. Two innovative works have shown the possibility of enhanced air ionization, with consequent AEF perturbations, in the preparatory stage of earthquakes (EQ): Freund et al. [2] base their arguments on charge separation generated in the stressed volume followed by positive charges flow...
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