Graz, June 2007 The DEMETER mission: Objectives and first results M. Parrot LPCE/CNRS 3A, Avenue de la Recherche Orléans cedex 2, France

Graz, June 2007 Outlines The project Case studies Statistic with the ELF/VLF electric field Statistic with the ES turbulence during seismic activities Conclusions

Graz, June 2007 The Project The DEMETER micro-satellite has been launched on June 29, 2004 by a Dnepr rocket from Baïkonour. The plate-form is under the CNES responsibility and the scientific payload was provided by scientific laboratories.

Graz, June 2007 The scientific objectives The scientific objectives of the DEMETER micro-satellite are related to the study of ionospheric perturbations in relation with the seismic and volcanic activities. These perturbations are interesting because they can be considered as short-term precursors (they occur between a few hours and a few days before a quake). The same payload will allow to survey the ionospheric perturbations in relation with man-made activities.

Graz, June 2007 The scientific payload The scientific payload of the DEMETER micro-satellite has several experiments: - A set of electric sensors to measure the 3 components of the electric field from DC to 3.5 MHz (CETP), - A three orthogonal search coil magnetometer to measure the magnetic field from a few Hz up to 20 kHz (LPCE), - Two Langmuir probes to measure the density and the temperature of the electrons (ESTEC), - An ion spectrometer to measure ion composition (CETP), - An energetic particle analyzer (CESR).

Graz, June 2007 The operations The orbit of DEMETER is polar, circular with an altitude of 710 km. DEMETER record data in two modes: a survey mode all around the Earth with low resolution, and a burst mode with high resolution above main seismic zones. The seismic parameters received from IPGP are merged with the orbital parameters in a special file of events.

Graz, June 2007

The wave experiment NEURAL NETWORK –number of whistlers and dispersion. BURST MODE –waveforms of 3 electric components up to 15 Hz, –waveforms of 6 components of the EM field up to 1.25 kHz, –waveforms of 2 components (1B + 1E) up to 20 kHz, –spectra of one electric component up to 3.5 MHz, –spectra of 2 components (1B + 1E) up to 20 kHz, –waveforms of one electric component up to 3.5 MHz (snapshots). SURVEY MODE –waveforms of 3 electric components up to 15 Hz, –spectra of 2 components (1B + 1E) up to 20 kHz, –spectra of one electric component up to 3.5 MHz.

Graz, June 2007

LPCE (IMSC, RNF, BANT) DEMETER DATA ACQUISITION ARCHIVE (Science data L0, QL, L1; Earthquake data; Ancillary data) WEB DATA SERVER (Data L0, QL, L1, L2; Earthquake events; Ancillary data products; Mission information) Science PL TM packets PL TC PLAN SCIENCE PL PROGRAMMATION GENERATION CONTROL CENTER PHYSICAL VALUES PROCESSING [L1] ANCILLARY DATA - Orbit Parameters - TM station Pass-Planning - Events (orbit, satellite) - Attitude - HK OPERATION BOARD OPERATION BOARD DEMETER MISSION GROUP (Experimenters, CNES) DEMETER MISSION GROUP (Experimenters, CNES) Science operation coordination PL and MC events Memory handling BURST zones LPCE (MC) CETP (IAP, ICE) 8 GHz SCIENTIFIC USERS SCIENTIFIC USERS Science PL TM packets « back-up » QUICK-LOOK PROCESSING [L0'] PRE-PROCESSING [L0] (Decommutation, Good Health) TM CESR (IDP) ESTEC (ISL) IPGP SEISMIC DATA Calibration validation Instrument configuration 2 GHz CNES EXCHANGE FILE SERVICE ANCILLARY DATA PROCESSING INSTRUMMENT CALIBRATIONS High resolution display [L2] PL status OPERATION COORDINATION GROUP OPERATION COORDINATION GROUP The DEMETER mission center

Graz, June 2007 One day in the DEMETER life (August 12, 2004) d = 2800 km

Graz, June 2007 Case studies

Graz, June 2007 Sarkar et al., JASTP, submitted, Central Iran 22 Feb :25:26 UT M = 6.4 d = 42.4 km Lat = 30.7°N, Long = 56.8°E The Results: DEMETER data

Graz, June 2007 Sarkar et al., JASTP, in press, days before 4 days before2 days before

Graz, June 2007 Sarkar et al., JASTP, submitted, Electron Density Variation of Ion Density

Graz, June Jan :10:11 UT -1.22°S °E M = 6.2

Graz, June Jan :10:11 UT -1.22°S °E M = days before 140 Hz

Graz, June 2007

Statistical analysis with the ELF/VLF electric field

Graz, June months of data 4385 hours of measurements Electric field data organized by - Frequencies (16) below 10 kHz - Magnetic local time (2) - Geographic positions (bin of 4° in longitude, 2° in latitude) - Kp classes (3) - Seasons (2)

Graz, June 2007 Electric field map

Graz, June 2007 Application of the central limit theoremProbability density function of the wave intensities in a bin

Graz, June earthquakes with M > 4.8 and d < 40 km Distance between epicenter and track of the orbit < 700 km

Graz, June Earthquakes with random position and time

Graz, June earthquakes with M > 4.8 and d < 40 km Aftershocks have been removed and data set extended (Feb.2007) 2111 earthquakes with M > 5.0 and d < 40 km Night time

Graz, June 2007 random Aftershocks have been removed and data set extended (Feb.2007) 2111 earthquakes with M > 5.0 and d < 40 km Night time

Graz, June 2007 Statistical analysis of the electrostatic turbulence

Graz, June Nov :26:25 UT °S °E M = day before

Graz, June 2007 M = days before

Graz, June 2007 Estimation of the power law (f –α ) during a ‘Survey’ mode with ICE

Graz, June 2007 Examples of global maps of the slope

Graz, June 2007 Examples of global maps of the slope

Graz, June 2007 Method of superposed epochs earthquakes of magnitude > 4.8 ; period 2004/08 – 2005/08; - Distance between the projection of the orbit on the Earth’s surface and the epicenter < 2000 km - Data selected in the time interval 3 days before the earthquakes and 1 day after the earthquakes. - Comparison between the current data during the seismic activity and the average background data at the same location during the same condition

Graz, June 2007 Decimal logarithm of the ratio between the current values of the power density and the ‘‘background’’

Graz, June 2007 EQs Random

Graz, June 2007 Ratio between the current values of the slope and the ‘‘background’’

Graz, June 2007 EQs Random

Graz, June 2007 Method of superposed epochs earthquakes of magnitude > 4.8 ; period 2004/08 – 2005/12; aftershocks have been removed. - Distance between the projection of the orbit on the Earth’s surface and the epicenter < 2000 km - Data selected in the time interval 3 days before the earthquakes and 1 day after the earthquakes. - Comparison between the current data during the seismic activity and the average background data at the same location during the same condition

Graz, June 2007 Decimal logarithm of the ratio between the current values of the power density and the ‘‘background’’

Graz, June 2007 EQs Random Average change at maximum equal to 2 ( )

Graz, June 2007 Average Histogram Comparison between two methods

Graz, June 2007 Ratio between the current values of the slope and the ‘‘background’’

Graz, June 2007 Random EQs Average maximum change = 18%

Graz, June 2007 Histogram Average Comparison between two methods

Graz, June 2007 Conclusions (1/3) The main points revealed by the statistical studies are: -The values of the parameters when the satellite is far from the earthquakes are similar to the values obtained when a random data set of events is used. Therefore this study shows that there is an influence of the seismic activity on the ES turbulence at an altitude of 700 km both before and after the earthquakes. -The perturbations are observed until 2 days before the earthquakes. There is a clear change right after the earthquakes. - The perturbations are real but they are weak and only statistically revealed. Up to now nothing can be said about the possibility to predict earthquakes with the analysis of the ES turbulence.

Graz, June 2007 Conclusions (2/3) Statistical analysis are in progress with other parameters: - Electron density and temperature - Whistler dispersion - Energetic particles - VLF Transmitters

Graz, June 2007 Conclusions (3/3) Operations will continue until the end of Altitude was decreased in December 2005 (660 km). The web site of the mission: