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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS009 Poster presentation 2050
Study of ground data VLF radio anomaly related to seismicity revealed by
DEMETER satellite on 2004: phase analysis
Dr. Tommaso Maggipinto
Department of Physics University of Bari
P.F. Biagi, L. Castellana, R. Piccolo, A. Minafra, A. Ermini, V. Capozzi, M. Solovieva,
O. Molchanov, M. Hayakawa
The studies on VLF signals collected by ground receivers continue to reveal the existence of
disturbances related to the seismicity. Recent papers report anomalies in VLF data collected from
satellite too. In particular, the analysis of the VLF signals received on board of the French DEMETER
satellite, revealed a drop of the signals (scattering spot) in the time interval November 23 December 12,
2004, probably connected with the occurrence of large earthquakes (M = 5.4-5.5) in Europe. The
lithosphere-atmosphere coupling model provides the theoretical explanation of the very complex
relations linking earthquakes and precursors. In this framework, we have analysed the phase of the
VLF/LF radio signals radiated by GB (f = 16 kHz, United Kingdom), FR (f = 20.9 kHz, France), GE (f =
23.4 kHz, Germany), IC (f = 37.5 kHz, Island) and IT (f = 54 kHz, Sicily, Italy) and received at Bari
(Italy), during October-December 2004. At first the wavelet analysis was applied on the phase data and
clear anomalies were revealed on the FR and IC signals at the end of November. So, an agreement with
the results obtained by the DEMETER seems to appear. Then the standard deviation of the phase data
sets was investigated and a clear short drop was revealed on the GE signal on 26-27 November. This
anomaly could be a precursor of one of the previous earthquakes and this result goes beyond the ones
obtained by satellite analysis.
Keywords: earthquakes, vlf radiosignals, statistical analysis