"Real time analysis" of the ion density measured by the satellite DEMETER in relation with the seismic activity
- 1Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, Université d'Orléans, UMR7328, CNRS, 3A Avenue de la Recherche Scientifique, 45071 Orléans cedex 2, France
- 2China Earthquake Networks Center, China Earthquake Administration, No. 5, Sanlihe Nanhengjie, Xicheng District, 100045 Beijing, China
- 3China University of Geosciences, No. 29, Xueyuan Road, Haidian District, 100083 Beijing, China
Abstract. This paper is related to the study of the ion density recorded by the low altitude satellite DEMETER. In a first time there is an automatic search for ionospheric perturbations in the complete satellite data set of ion densities. Then perturbations due to known ionospheric phenomena (for example, solar activity) are eliminated as well as perturbations not above a seismic zone. In a second time, there is a search to know if each selected perturbation corresponds to a future earthquake. The earthquakes have been classified depending on their magnitude and depth. This attempt to predict earthquakes of course generates false alarms and wrong detections. The results of this statistical analysis are presented as function of various parameters. It is shown that the number of false alarms is very important, because the ionosphere has variations not only linked to the seismic activity. The number of wrong detections is also important and can be explained by the fact that the satellite is above a seismic area only a few minutes per day and we do not expect continuous perturbations from a given earthquake. The more important results of this study is that the ratio between detected earthquakes and earthquakes to be detected increases with the magnitude of the earthquakes which intuitively makes sense.