HR: 13:55h
AN: T52D-02 INVITED     [PDF]
TI: Electron Density Variations in the Ionosphere During the Gujarat Earthquake Event
AU: * Parrot, M
EM: mparrot@cnrs-orleans.fr
AF: LPCE/CNRS, 3A Avenue de la Recherche, Orleans, 45071 France
AU: Trigunait, A
EM: trigunait@cnrs-orleans.fr
AF: LPCE/CNRS, 3A Avenue de la Recherche, Orleans, 45071 France
AU: Pulinets, S
EM: pulse@geofisica.unam.mx
AF: Institute of Geophysics, UNAM, Mexico D.F., 04510 Mexico
AB: Ionospheric perturbations by natural geophysical activity, such as volcanic eruptions and earthquakes, have been studied since the great Alaskan earthquake in 1964. Measurements made from the ground show a variation of the critical frequency of the ionosphere layers before and after the shock. In this paper, we present an experimental investigation of the ionospheric electron density variations around the time of the Bhuj earthquake in Gujarat, India (23.4N, 70.3E, M = 7.6, d = 17 km). Several experiments have been used: the low-altitude satellite TOPEX-POSEIDON which measured fluctuations in the integrated electron density or TEC (Total Electron Content) between the satellite and the ground to correct the altimetry measurement, a GPS experiment which gives another TEC measurement from a fixed ground-based station in Bangalore (13.02N, 77.57E), and a ground-based ionospheric sounder in Ahemadabad (23.0N, 72.4 E). Anomalous electron density variations have been detected both in day and night times before the quake. A possible mechanism which could explain these variations is given.
DE: 2435 Ionospheric disturbances
DE: 2481 Topside ionosphere
DE: 6929 Ionospheric physics (2409)
DE: 6934 Ionospheric propagation (2487)
DE: 7215 Earthquake parameters
SC: Tectonophysics [T]
MN: 2003 Fall Meeting