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The DEMETER mission: Objectives and first results

The DEMETER mission: Objectives and first results. M. Parrot LPCE/CNRS 3A, Avenue de la Recherche 45071 Orléans cedex 2, France E-mail: mparrot@cnrs-orleans.fr. Outlines The project Case studies Statistic with the ELF/VLF electric field

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The DEMETER mission: Objectives and first results

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  1. The DEMETER mission: Objectives and first results M. Parrot LPCE/CNRS 3A, Avenue de la Recherche 45071 Orléans cedex 2, France E-mail: mparrot@cnrs-orleans.fr Graz, June 2007

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

  3. 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

  4. 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

  5. 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

  6. 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

  7. Graz, June 2007

  8. 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

  9. Graz, June 2007

  10. The DEMETER mission center 8 GHz 2 GHz EXCHANGE FILE SERVICE ANCILLARY DATA PROCESSING PRE-PROCESSING [L0] (Decommutation, Good Health) INSTRUMMENT CALIBRATIONS PHYSICAL VALUES PROCESSING [L1] ARCHIVE (Science data L0, QL, L1; Earthquake data; Ancillary data) High resolution display [L2] WEB DATA SERVER (Data L0, QL, L1, L2; Earthquake events; Ancillary data products; Mission information) CNES ANCILLARY DATA - Orbit Parameters - TM station Pass-Planning - Events (orbit, satellite) - Attitude - HK CONTROL CENTER OPERATION COORDINATION GROUP Science PL TM packets « back-up » Science PL TM packets PL TC PLAN LPCE (MC) SEISMIC DATA DEMETER DATA ACQUISITION IPGP TM SCIENCE PL PROGRAMMATION GENERATION QUICK-LOOK PROCESSING [L0'] Memory handling BURST zones Calibration validation SCIENTIFIC USERS OPERATION BOARD PL status Science operation coordination PL and MC events Instrument configuration LPCE (IMSC, RNF, BANT) CETP (IAP, ICE) DEMETER MISSION GROUP (Experimenters, CNES) CESR (IDP) ESTEC (ISL) Graz, June 2007

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

  12. Case studies Graz, June 2007

  13. The Results: DEMETER data Central Iran 22 Feb. 2005 02:25:26 UT M = 6.4 d = 42.4 km Lat = 30.7°N, Long = 56.8°E Sarkar et al., JASTP, submitted, 2007. Graz, June 2007

  14. 4 days before 2 days before 6 days before Sarkar et al., JASTP, in press, 2007. Graz, June 2007

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

  16. 23 Jan. 2005 20:10:11 UT -1.22°S 119.82°E M = 6.2 Graz, June 2007

  17. 23 Jan. 2005 20:10:11 UT -1.22°S 119.82°E M = 6.2 140 Hz 2.5 days before Graz, June 2007

  18. Graz, June 2007

  19. Graz, June 2007

  20. Statistical analysis with the ELF/VLF electric field Graz, June 2007

  21. 15 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

  22. Electric field map Graz, June 2007

  23. Probability density function of the wave intensities in a bin Application of the central limit theorem Graz, June 2007

  24. Distance between epicenter and track of the orbit < 700 km 2628 earthquakes with M > 4.8 and d < 40 km Graz, June 2007

  25. 2628 Earthquakes with random position and time Graz, June 2007

  26. Aftershocks have been removed and data set extended (Feb.2007) 3346 earthquakes with M > 4.8 and d < 40 km 2111 earthquakes with M > 5.0 and d < 40 km Night time Graz, June 2007

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

  28. Statistical analysis of the electrostatic turbulence Graz, June 2007

  29. 22 Nov. 2004 20:26:25 UT -46.57°S 164.83°E M = 7.3 1 day before Graz, June 2007

  30. M = 5.2 5 days before Graz, June 2007

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

  32. Examples of global maps of the slope Graz, June 2007

  33. Examples of global maps of the slope Graz, June 2007

  34. Method of superposed epochs • 4626 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

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

  36. EQs Random Graz, June 2007

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

  38. EQs Random Graz, June 2007

  39. Method of superposed epochs • 2173 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

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

  41. EQs Average change at maximum equal to 2 (100.8-0.52) Random Graz, June 2007

  42. Comparison between two methods Average Histogram Graz, June 2007

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

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

  45. Comparison between two methods Average Histogram Graz, June 2007

  46. 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

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

  48. Conclusions (3/3) • Operations will continue until the end of 2008. • Altitude was decreased in December 2005 (660 km). • The web site of the mission:http://demeter.cnrs-orleans.fr Graz, June 2007

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