Workshop on Earthquakes: Ground-based and Space Observations

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1 Space Research Institute, Austrian Academy of Science, Graz, Austria 2 Institute of Physics, Department of Theoretical Physics, KF University Graz, Austria 3 Centre d'Étude des Environnements Terrestre et Planétaires, Observatoire de Saint-Maur, France 4 Geophysical Institute, Sofia, Bulgaria 5 Institute of Physics, Department of Geophysics, Astrophysics and Meteorology (IGAM), KF University Graz, Austria 6 Communication Networks and Satellite Communications Institute, TU University Graz, Austria

ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

M.Y. Boudjada1, H. Biernat1,2, K. Schwingenschuh1, J.J. Berthelier3,

E. Cristea1, P. Pesec1, P. Nenovski4, M. Horn5, G. Prattes6, M. Stachel1

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

We report on the possible relationship between the seismic event occurrence and the VLF and ELF emissions as recorded by the ‘Instrument Capteur Electrique’ (ICE) experiment onboard the DEMETER micro-satellite. For this we analyze two seismic events which occurred on 24th and 25th Nov., 2004, in the Adriatic region, at the geographic coordinates of (45.66° N; 10.64° E) and (43.24° N; 15.58° E), respectively. The seismic intensity magnitude was of about 5.2, and both events were separated by a distance of 594 km. These earthquake events are combined to ELF/VLF space observations and ground measurements performed by the DEMETER/ICE experiment and GPS permanent stations, respectively. A method is applied and used to find an eventual correlation between these seismic events and the ground-based and space observations. This method is principally based on a statistical approach which lead to: (a) study the temporal variations before and after the earthquakes, (b) classify the observed features, and (c) estimate the measurement accuracy and the corresponding source of errors.

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

ICE experiment on board DEMETER micro-satellite

Selected Adriatic seismic events (24th and 25th Nov., 2004)

Ground-based and Space observations

ULF observations

GPS observations

DEMETER/ICE observations

Spectral method as tool to characterize the ELF/VLF emission activity Classification of ‘well’ known ionospheric emissions

Adriatic seismic events

Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

Cross-correlation: Preliminary results

Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

3 Electric components of the wave field- ULF, DC to 15 Hz, the potential of the 4 sensors- ELF, 10 Hz to 1 kHz, 3 channels- VLF, 10 Hz to 18 kHz, 1 channel- HF, 70 Hz to 3.125 MHz, 1 channel

Berthelier et al., 2006

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

24th Nov.

25th Nov.

IWF

Event of 24th Nov. 2004:

(a) Lat. = 45.66°N,

Long.=10.64°E

(b) Time: 22:59:39

(c) Magnitude: 5.30

Event of 25th Nov. 2004:

(a) Lat. = 43.24°N,

Long.= 15.58°E

(b) Time: 06:21:19

(c) Magnitude: 5.20

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

SEGMA Network (a) Continuous ULF data set(b) Polarization (V/H) studies for the period August until December 2004(c) Lowest noise level for RNC in the Pc4 band found

Schwingenschuh et al. (2005)

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

GPS ground-space

(a) The closest station to event of 24th Nov., 04.

(b) Time series 4 weeks

(c) Daily solutions for: • North component• East component• Up component

(d) Days 32 and 33

(24th/25th,Nov., 2004).

Cristea et al. (2005)

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

DEMETER/ICE observations• Spectrogram of one electric component (E12) • Time resolution: 2.048 sec.• Frequency resolutions: (a) 78 Hz from 10 Hz to 1.7 kHz

(b) 312 Hz between 1.7 kHz and 18 kHz.

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

Whistlersemission

Chorus emissions

Hiss emission

One dynamic spectrum of one half-orbit has 980x1024 measurements ( 106 points)

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

Second period: 23rd, 24th,25th Nov. 2004

First period: 03rd, 04th, 05th Nov. 2004

DEMETER observations:

(a) Coverage in Latitude and Longitude

(b) Two time periods• 23rd, 24th,25th Nov. 2004• 03rd, 04th, 05th Nov.2004

Event of 24th Nov. 2004:

(a) Lat. = 45.66°N,

Long.=10.64°E

(b) Time: 22:59:39

Event of 25th Nov. 2004:

(a) Lat. = 43.24°N,

Long.= 15.58°E

(b) Time: 06:21:19

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

Second period

23rd, 24th,25th Nov. 2004

First period

03rd, 04th,05th Nov. 2004

Frequency occurrence for all observed components

(Hiss, Chorus, Equatorial Noise, Whistlers

Frequency (fmin and fmax) occurrences are identical.

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

Earthquakes recorded in the period 01 Sept. – 31 Dec., 2004 2/3 events per day

Magnitude ~ 5.3

25th Nov. 20004

Selected period of Earthquakes08th Sept. – 23rd Oct., 2004

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

DEMETER/ICE observations 08th Sept. – 23rd Oct., 2004

1 k

Hz

5 k

Hz

10 k

Hz

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

Result of the cross-correlation betweenELF/VLF emissions and Earthquakes magnitudes

Correlation

Coefficient

Frequency

(Hz)

Lag(Day

)

0.58 664.063 5

0.50 683.594 5

0.50 5410.16 5

0.50 5429.69 5

0.50 17070.3 2

Cross-correlation

(a) We consider the cross-correlation equal/bigger than 0.5

(b) ELF Emissions (freq.~ 650 Hz) and VLF (freq. ~ 5.5 kHz and freq. ~17 kHz). ‘seem’ to be correlated to the Earthquakes magnitudes.

(c) The lag-time is about 5 days before the Earthquakes.

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Workshop on Earthquakes: Ground-based and Space Observations

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ICE experiment onboard DEMETER satelliteCase study of two seismic events in the Adriatic

1. ICE experiment DEMETER micro-satellite

2. Selected Adriatic seismic events (24th and 25th

Nov., 2004)

3. Ground-based and Space observations

3.1. ULF ground Network

3.2. GPS ground-space

3.3. DEMETER/ICE

3.3.1. Spectral method as tool to characterize the ELF/VLF emission activity

3.3.2. Classification of ‘well’ known ionospheric emissions

3.3.3. Adriatic seismic events

3.3.4. Statistical studies of ELF/VLF emissions as recorded by DEMETER/ICE

4. Cross-correlation (08th Sept. – 23rd Oct.2004)

4.1. Selected Earthquakes

4.2. Selected DEMETER/ICE

4.3 Cross-correlation

5. Conclusion

Conclusion

(a) DEMETER observations: ELF/VLF occurrences are found to be similar before (few days) and during the two Adriatic seismic events.

(b) DEMETER ELF/VLF emissions versus Earthquakes magnitudes:

• ELF emissions ‘seem’ to be more adapted for earthquakes precursors studies.

• This results could be a simple ‘coincidence’

(c) Define precise methods which lead to combine the ground-based and space observations.