Seismo-ionosphere detection by underground SQUID in low-noise environment in LSBB-Rustrel, France

¹ Université de Nice Sophia-Antipolis, Observatoire de la Côte d'Azur, Laboratoire Souterrain Bas Bruit de Rustrel-Pays d'Apt (LSBB), La Grande Combe, 84400 Rustrel, France
² Université Paris XIII, LPMTM, Institut Galilée, 93430 Villetaneuse, France
³ Université d'Avignon et des Pays de Vaucluse, Département de Physique, Rue Louis Pasteur, 84000 Avignon, France
⁴ Université de Nice Sophia-Antipolis, GéoSciences-Azur, 250 rue Albert Einstein, 06500 Sophia-Antipolis, France
⁵ Université Paris7-Denis Diderot, 2 Place Jussieu, 75005 Paris, France
⁶ Université Aix-Marseille IM2NP, UMR 6242 CNRS, Faculté des Sciences et Techniques, Avenue Normandie Niemen, 13397 Marseille Cedex 20, France
⁷ Université d'Orléans, LPCE CNRS, 3A av. de la Recherche Scientifique, 45071 Orléans, France

Corresponding author: georges.waysand@oca.eu

Received: 30 May 2008
Revised: 4 July 2008
Accepted: 14 October 2008
Published online: 17 February 2009

Abstract

The permanent operation of a 3 axes SQUID magnetometer in the LSBB below 550 m of calcite rock is a unique system of magnetic observation: a rejection rate better than 3 fT/Hz over 40 Hz. The observation of magneto-ionosphere responses to P wave emissions both at the epicentre and at their arrival at LSBB for earthquakes of magnitude larger than 3 is reported. A simple model predicts the starting time of these events. These results are compared with those provided by Doppler sounders for ionosphere responses to Rayleigh waves.