The DEMETER satellite: Payload, Operations and Data M. Parrot LPC2E/CNRS 3A, Avenue de la Recherche 45071 Orléans cedex 2, France E-mail: [email protected]

Tunis, Awesome June 2009

Outlines

The Project The hypotheses about the seismo EM effect Observations during seismic activities Statistical analysis Conclusions

Tunis, Awesome June 2009

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. Tunis, Awesome June 2009

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. Tunis, Awesome June 2009

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). Tunis, Awesome June 2009

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Measured Parameters • • • • • • • • • •

Frequency range, B Frequency range, E Sensibility B : Sensibility E : Particles: electrons Ionic density: Ionic temperature: Ionic composition: Electron density: Electron temperature:

10 Hz - 20 kHz DC – 3.5 MHz 1. 10-5 nT Hz-1/2 at 1 kHz 0.2 µV Hz-1/2 at 500 kHz 60 keV – 600 keV 5 102 - 5 106 ions/cm3 1000 K - 5000 K H+, He+, O+ 102 - 5 106 cm-3 500 K - 3000 K Tunis, Awesome June 2009

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. Tunis, Awesome June 2009

DEMETER orbit

DEMETER orbit

North conjugate point of the epicenter at the satellite altitude

Earthquake epicenter

d1

d2

dmcN

North conjugate point of the epicenter at the satellite altitude

d3 dm

d4 dmc

Conjugate point of the epicenter

dmcS

South conjugate point of the epicenter at the satellite altitude

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South conjugate point of the epicenter at the satellite altitude

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. Tunis, Awesome June 2009

Tunis, Awesome June 2009

The DEMETER mission center CNES ANCILLARY DATA - Orbit Parameters - TM station Pass-Planning

CONTROL CENTER OPERATION OPERATION COORDINATION COORDINATION GROUP GROUP

PL TC PLAN

2 GHz

8 GHz

- Events (orbit, satellite) - Attitude - HK

Science PL TM packets « back-up »

Science PL TM packets

EXCHANGE FILE SERVICE

LPCE

SEISMIC DATA

DEMETER DATA ACQUISITION

(MC)

IPGP TM

SCIENCE PL PROGRAMMATION GENERATION

PRE-PROCESSING [L0] (Decommutation, Good Health)

ANCILLARY DATA PROCESSING

INSTRUMMENT CALIBRATIONS PHYSICAL VALUES PROCESSING [L1]

QUICK-LOOK PROCESSING [L0']

Memory handling BURST zones Calibration validation

OPERATION OPERATION BOARD BOARD

Science operation coordination

ARCHIVE (Science data L0, QL, L1; Earthquake data; Ancillary data)

High resolution display [L2]

PL and MC events

WEB DATA SERVER (Data L0, QL, L1, L2; Earthquake events; Ancillary data products; Mission information)

Instrument configuration

LPCE (IMSC, RNF, BANT)

DEMETER DEMETER MISSION GROUP MISSION GROUP (Experimenters, (Experimenters, CNES) CNES)

SCIENTIFIC SCIENTIFIC USERS USERS

PL status

CETP (IAP, ICE)

CESR (IDP)

ESTEC (ISL)

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One day in the DEMETER life (August 12, 2004)

d = 2800 km 10 LT 22 LT

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Outlines

The Project The hypotheses about the seismo EM effect Observations during seismic activities Statistical analysis Conclusions

Tunis, Awesome June 2009

Hypotheses on the generation mechanism of these seismoelectromagnetic perturbations: •Propagation of EM waves from the ground. –Only ULF waves can appear at the Earth’s surface, –Propagation in a wave guide (the fault) or change in the ground resistivity? –Wave-wave interaction in the ionosphere. •Propagation of Acoustic-Gravity Waves. –As far as they propagate, the AGW amplitude increases due the decrease of the atmospheric density

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•The piezo-electric and tribo-electric effects. –Apparition of electric charges at the Earth’s surface, –Change of the atmospheric conductivity, –Change of the atmosphere-ionosphere coupling currents

from Markson, 1978

•The emissions of aerosols (radioactive gas or metallic ions). Transportation to ionospheric layers due to: –atmospheric turbulence and thermospheric winds, –increase of the atmosphere conductivity, penetration of electric fields and ion acceleration

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First paper on the seismo-electromagnetic effects by Milne in 1890

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Gokhberg et al. (1982)

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Observations of Seismo-Electromagnetic effects Laboratory experiment (Cress et al., GRL, 1987)

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Observations of Seismo-Electromagnetic effects Radon concentration data in a well close to Kobe

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(courtesy of P.F. Biagi)

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Outlines

The Project The hypotheses about the seismo EM effect Observations during seismic activities Statistical analysis Conclusions

Tunis, Awesome June 2009

Examples of ionospheric perturbations in possible correlation with seismic activity

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Altitude of DEMETER

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13 Juin 2008 23:43:46 UT Lat 39.103° Long 140.668° d = 10 km M = 6.8

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2,5 days before

DEMETER orbit North conjugate point of the epicenter at the satellite altitude

Earthquake epicenter

d1

d2

d3

d4

Conjugate point of the epicenter

South conjugate point of the epicenter at the satellite altitude

200 km

Tunis, Awesome June 2009

from K. Hattori

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Outlines

The Project The hypotheses about the seismo EM effect Observations during seismic activities Statistical analysis Conclusions

Tunis, Awesome June 2009

Statistical analysis with the electric field data

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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)

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Electric field map

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Probability density of the intensity of the waves in a cell

Application of the central limit therorem

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de Braile, AGU, 2004

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Superposed epoch method Time of EQ 26 June 2007 00:30:00 UT

x x x x x x x x x x x x

x x x x x x x x x x x x x x x x x x x x

►

►

10 Hours before

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14 Hours 30 after

Night time VLF Electric field between 1055 – 2383 Hz

Distance (km)

-4σ -2σ 0σ 2σ 4σ Normalized Probabilistic Intensity

600 400 200 0 -40

-20 0 Time (Hours)

2111 EQs with M > 5.0 and d < 40 km Tunis, Awesome June 2009

20

-4σ -2σ 0σ 2σ 4σ Normalized Probabilistic Intensity

8

8

Frequency (kHz)

Frequency (kHz)

-4σ -2σ 0σ 2σ 4σ Normalized Probabilistic Intensity

6 4 2 0

6 4 2 0

-40

-20 0 Time (Hours)

20

3346 earthquakes with M > 4.8 and d < 40 km Night time

-40

-20 0 Time (Hours)

20

2111 earthquakes with M > 5.0 and d < 40 km

Tunis, Awesome June 2009

-4σ -2σ 0σ 2σ 4σ Normalized Probabilistic Intensity

8

8

Frequency (kHz)

Frequency (kHz)

-4σ -2σ 0σ 2σ 4σ Normalized Probabilistic Intensity

6 4 2 0

6 4 2 0

-40

-20 0 Time (Hours)

random Night time

20

-40

-20 0 Time (Hours)

20

2111 earthquakes with M > 5.0 and d < 40 km Tunis, Awesome June 2009

We observe a decrease of the electric field at ~ 1.7 kHz during night time This is the frequency cutoff of the Earth-ionosphere waveguide (h= 90 km)

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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 ionospheric parameters at an altitude of 700 km before the earthquakes. -The perturbations are observed a few hours before 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 ionospheric parameters.

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Conclusions (2/3) Statistical analysis are in progress with other parameters: - Electron density - Electrostatic turbulence - Whistler dispersion - Energetic particles - VLF Transmitters

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Conclusions (3/3) 72 publications (end of May) The website of the mission: http://demeter.cnrs-orleans.fr Operations will continue at least until the beginning of 2010.

Tunis, Awesome June 2009