Study of VLF emissions apparently associated with earthquakes from ground-based and GEOS satellites data

VLF emissions, apparently associated with earthquakes, have been independently observed at the Kerguelen station(49 deg 26'S,70 deg 25'E) and on the GEOS-1 and GEOS-2 satellites, at frequencies under 10 kHz. The observations at Kerguelen have been made on magnetic antennas, on April 24 and 25 1980, in a period when three earthquakes of moderate intensity (M ≅ 4.7) took place near the station. The observations on the GEOS satellites have been made from magnetic and electric antennas during the period 1977-1981. The analysis has been performed selecting the cases for which, on the one hand, intense earthquakes (M>5) occurred in regions close to the satellite longitude (GEOS-2 is geostationary and its geographical longitude is ≅ 22 deg E) and, on the other hand, the satellite is operating in a VLF mode. Methods of distinction between correlations and coincidences are discussed