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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy (S) - IASPEI - International Association of Seismology and Physics of the Earth's Interior JSS010 Poster presentation 2089 Analysis of ionospheric electrostatic turbulence over seismic regions using DEMETER plasma and wave measurements Dr. Tatsuo Onishi Jean-Jacques Berthelier Several recent results have pointed out the existence of ionospheric disturbances associated with seismic activity. Of great interest, in particular, is the possible occurrence of disturbances prior to the main shock that can be thought as ionospheric precursors of earthquakes. One of the goals of the DEMETER mission is to perform an in-situ study of the ionospheric plasma and waves in order to search for events associated to seismic activity and to characterize pre- and post-seismic effects. Using measurements of the electric components of plasma waves in the ULF/ELF/VLF ranges provided by the ICE instrument and thermal plasma measurements from the IAP instrument, we have studied the natural emissions that are observed over seismically active regions with an initial focus on the low frequency electrostatic turbulence and plasma irregularities. The electromagnetic interferences onboard DEMETER have been maintained to a low level. However, it is expected that events associated with seismic activity have a weak intensity, and we have paid a careful attention to detect the occurrence of electromagnetic interferences, understand their origin and estimate their effect on power spectra. Similarly we have tried to recognize as far as possible natural emissions that arise from space weather effects and are not linked with seismic activity in order to minimize their impact on the statistical distribution of low level signals. In order to distinguish the true pre-seismic events from post-seismic disturbances, a number of earthquakes were carefully selected from the earthquake database so as not to include other seismic events of significant importance during the 5 preceding days within the same seismic region. In this talk we shall present the most important aspects of the methodology that have been followed to analyze the data and discuss current results from this on-going study. Keywords: demeter, vlf, electrostatic

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy (S) - IASPEI - International Association of Seismology and Physics of the Earth's Interior JSS010 Poster presentation 2090 Statistical study of anomalous fluctuations of whistler data recorded by DEMETER Dr. Aurora Buzzi Physics Roma Tre University IASPEI Livio Conti, Michel Parrot, Jean-Louis Pincon, Vittorio Sgrigna, David Zilpimiani It has been carried out a statistical analysis on the spatial and temporal distributions of whistlers detected by the RNF experiment on board the micro-satellite DEMETER. Several cuts and constrains (on the geomagnetic conditions, whistler propagation modes, etc.) have been applied to data in order to discriminate possible whistler anomalous fluctuations with respect to the mean monthly and geographical background values. Assuming a ducted propagation of whistler-waves along the magnetic field line, a few mathematical estimators of the signal-to-noise ratio have been introduced to estimate the statistical significance of anomalous signals. Aim of the study is to search whistler fluctuations possibly associated with earthquakes. Keywords: whistler, earthquake, demeter

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