Ionospheric variations at the time of the M8.8 Chile earthquake and statistical analysis of plasma parameters recorded by DEMETER - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2010

Ionospheric variations at the time of the M8.8 Chile earthquake and statistical analysis of plasma parameters recorded by DEMETER

Résumé

DEMETER is a low orbiting satellite (650 km) which is operating more than six years to study ionospheric perturbations in relation with the seismic activity. It records wave and plasma parameters all around the Earth (except in the auroral zones) at two different local times (10.30 and 22.30 LT). This paper will present observations performed during the M8.8 Chile earthquake on February 27, 2010. They show a perturbation of the ionospheric density at the satellite altitude a few days before the quake. Publication of these results was not accepted in GRL despite the uniqueness of this observation. To reject the paper, an anonymous referee said that many other parameters can fluctuate before the quake including the stock market. It is true, but our parameter is not the London or the New York stock market; it is a physical parameter which is measured in close proximity to the earthquake. It is a parameter which characterizes the environment above the future epicentre. The physical mechanism which induces these perturbations is not yet known (there are several hypotheses) but it is know that it exists a fair weather electric field between the bottom of the ionosphere and the ground. Whatever is the mechanism, if there is a change on the ground it will be registered in the ionosphere. But it is also known that the ionosphere is highly variable and that perturbations could come from other sources (solar activity, AGW, TID, plasma dynamics, large meteorological phenomena…). Then the paper will show a new statistical analysis performed on the plasma parameters during night time. An algorithm has been implemented to detect crests and troughs in the data before earthquakes. The earthquakes have been classified depending on their magnitude, depth, and location (land, below the sea, close to a coast). Due to the orbit, DEMETER returns above the same area every day (once during day time, once during night time) but not at the same distance of a given epicentre. Then, for each earthquake, data have been checked until 15 days before the shock when the distance between the trace of the orbit and the epicentre is less than 1500 km. The results of the statistical analysis are presented as function of various parameters. A comparison is done with two other data bases where, on one hand, the location of the epicentres has been randomly modified, and on the other hand, the longitude of the epicentres has been shifted.
Fichier non déposé

Dates et versions

hal-03548977 , version 1 (31-01-2022)

Identifiants

Citer

Michel Parrot. Ionospheric variations at the time of the M8.8 Chile earthquake and statistical analysis of plasma parameters recorded by DEMETER. American Geophysical Union, 2010, à renseigner, Unknown Region. pp. 1542-1550. ⟨hal-03548977⟩
28 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More