Investigating the seismic cycle in Italy by multitemporal analysis of ALOS, COSMO-SkyMed and ERS/Envisat DInSAR data sets ...
Outline <ul><li>The  SIGRIS  Project (funded by Italian Space Agency): exploiting Earth Observation data for seismic risk ...
Two operations mode <ul><li>To generate EO-based, value-added products for the operational use by the National Civil Prote...
What we produce Ground velocity maps at the fault scale The SIGRIS PR1 products are maps showing the small (mm/yr) progres...
What data we use <ul><li>SAR data </li></ul><ul><li>Same viewing geometry (interferometric acquisitions) </li></ul><ul><li...
DInSAR techniques <ul><li>We use multitemporal InSAR techniques: </li></ul><ul><li>SBAS - S mall  BA seline  S ubset (IREA...
SIGRIS Test Sites The SIGRIS Project considers 4 test areas in Italy. We processed over  1100  SAR images from ERS, ENVISA...
The Straits of Messina The largest earthquake of the XX century in Italy Mw = 7.1, in 1908 Debated earthquake source (at l...
Ground deformation using time-series DInSAR SAR Data: ERS   (1992-2001) 71 images (D), 37 (A) ENVISAT   (2003-2008) 34 ima...
Mean Ground Velocity Maps (LoS) Ascending Orbit  Descending orbit ERS+ENVISAT
Time Series examples
Up & East Velocity Maps Up Component East Component <ul><li>look angle = variable along the swath </li></ul><ul><li>We con...
Up Component Legend Up Velocity (mm/yr) _ +
East Component 4 mm/yr 0 mm/yr -5 mm/yr -1 mm/yr -4 mm/yr -9 mm/yr Legend East Velocity (mm/yr)
Temporal span: 10/01/07- 05/06/10 22 images ALOS Mean Ground Velocity Map (LoS) Processed with SARscape
What ALOS can detect 2 1 2007-2010 1992-2010 1 N S S W E 2
COSMO-SkyMed Ground Velocity map (LoS) Ascending orbit 1 2 Area 1 1st of October, 2009: Mud landslide, 30 casualties 1 1 2 2
The April 6, 2009 L’Aquila earthquake Co-seismic & post-seismic phase
Co-seismic deformation maps:  first clear SAR interferogram (ENVISAT desc) -27 cm LoS  displacement
Co-seismic deformation maps:  second clear SAR interferogram (COSMO asc) -25 cm LoS  displacement
Co-seismic deformation maps:  vertical ground displacement
Co-seismic deformation maps:  East ground displacement
The L’Aquila case <ul><li>Descending Orbit  </li></ul><ul><li>52 images ( Envisat ) </li></ul><ul><li>From February,2003 t...
Descending Pass Ascending Pass 26/02/2003- 14/07/2010 02/09/2003- 22/06/2010 ASAR Mean Velocity Map  (LoS) earthquake
ALOS Mean Velocity Map  (LoS) Track 639 Frame 830 Temporal span: 15/01/2007-26/07/2010 Processed with SARscape 16 images
Temporal span: 29/04/2009-13/10/2009 23 slc used Ascending Orbit COSMO-SkyMed Mean Ground Velocity Map  (LoS) Processed wi...
COSMO-SkyMed Displacement Map  (LoS)
Conclusions <ul><li>Multitemporal InSAR techniques are able to measure the ground deformation related to the seismic cycle...
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IGARSS_2011_final.ppt

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IGARSS_2011_final.ppt

  1. 1. Investigating the seismic cycle in Italy by multitemporal analysis of ALOS, COSMO-SkyMed and ERS/Envisat DInSAR data sets C.Tolomei , S. Atzori, J. P.Merryman, G. Pezzo, S. Salvi (1) (1) Istituto Nazionale di Geofisica e Vulcanologia - Rome, italy
  2. 2. Outline <ul><li>The SIGRIS Project (funded by Italian Space Agency): exploiting Earth Observation data for seismic risk management </li></ul><ul><li>SAR data processed and DInSAR techniques used </li></ul><ul><li>The Straits of Messina and the L’Aquila cases </li></ul><ul><li>Conclusions </li></ul>Further information: www.sigris.it
  3. 3. Two operations mode <ul><li>To generate EO-based, value-added products for the operational use by the National Civil Protection Service in two risk management phases: </li></ul><ul><li>Knowledge & Prevention, i.e. support to the Seismic Hazard assessment </li></ul><ul><li>Warning & Crisis, i.e. support to the Emergency management </li></ul><ul><li>During normal routine operations, the products for the Knowledge & Prevention (i.e. support to Seismic Hazard Assessment ), are generated </li></ul><ul><li>During a seismic Crisis , activated by the INGV surveillance system (SISMAP) for earthquakes > M5.5, products are generated in near-real time, in incremental versions </li></ul><ul><li>To identify factors limiting the EO data exploitation </li></ul>
  4. 4. What we produce Ground velocity maps at the fault scale The SIGRIS PR1 products are maps showing the small (mm/yr) progressive movements of the Earth’s surface occurred over a period of years. We use them to quantify the crustal deformation associated to the seismic cycle , in particular in the inter-seismic and post-seismic phases. The amount and patterns of crustal deformation are related to the tectonic stress accumulated and then released during the earthquakes .
  5. 5. What data we use <ul><li>SAR data </li></ul><ul><li>Same viewing geometry (interferometric acquisitions) </li></ul><ul><li>From ascending and descending passes </li></ul><ul><li>Consistent datasets (15-20 images minimum) </li></ul><ul><li>Minimum acquisition frequency: 2 months for L-band, 1 month for C-band, 10 days for X-band (note: some images can be discarded during processing) </li></ul><ul><li>CGPS data </li></ul><ul><li>Site displacement time series for the 3 cartesian components </li></ul><ul><li>Minimum 3 stations per SAR coverage for a correct SAR-GPS integration </li></ul><ul><li>To estimate and remove possible ramps </li></ul><ul><li>X-Band: Cosmo-SkyMed (April, 2009 ->), asc-desc </li></ul><ul><li>C-Band: ERS1/2 (1992-2001), asc-desc </li></ul><ul><li>ENVISAT (2003-2010), asc-desc </li></ul><ul><li>L-Band: ALOS (2007->), asc </li></ul>
  6. 6. DInSAR techniques <ul><li>We use multitemporal InSAR techniques: </li></ul><ul><li>SBAS - S mall BA seline S ubset (IREA-CNR), SARscape (Sarmap); </li></ul><ul><li>P ermanent S catterers (T.R.E.,Milano). </li></ul><ul><li>We validate the result using: </li></ul><ul><li>CGPS </li></ul><ul><li>levelling lines </li></ul><ul><li>Geological and seismological data. </li></ul><ul><li>Bernardino P. et al., 2002, A new algorithm for surface deformation monitoring based on Small Baseline Differential SAR Interferograms . IEEE Trans on Geosci. and Remote Sensing, 40. </li></ul><ul><li>Ferretti, A., C. Prati, and F. Rocca (2001), Permanent scatterers in SAR interferometry, IEEE Trans. Geosci. Remote Sens., 39(1), 8– 20. </li></ul>
  7. 7. SIGRIS Test Sites The SIGRIS Project considers 4 test areas in Italy. We processed over 1100 SAR images from ERS, ENVISAT, ALOS, and COSMO-SkyMed satellites. We generated, validated, and delivered to the Italian Civil Protection over 100 PR1 product items.
  8. 8. The Straits of Messina The largest earthquake of the XX century in Italy Mw = 7.1, in 1908 Debated earthquake source (at least 5 different fault models) To be crossed by a 4-km long suspended bridge From Amoruso et al, 2002, JGR Inter-seismic phase
  9. 9. Ground deformation using time-series DInSAR SAR Data: ERS (1992-2001) 71 images (D), 37 (A) ENVISAT (2003-2008) 34 images (A) ALOS (2007-2010) 22 images (A) COSMO-Skymed (2009-2010) 17 images (D)
  10. 10. Mean Ground Velocity Maps (LoS) Ascending Orbit Descending orbit ERS+ENVISAT
  11. 11. Time Series examples
  12. 12. Up & East Velocity Maps Up Component East Component <ul><li>look angle = variable along the swath </li></ul><ul><li>We constrained the SAR North component based on the CGPS one. </li></ul>
  13. 13. Up Component Legend Up Velocity (mm/yr) _ +
  14. 14. East Component 4 mm/yr 0 mm/yr -5 mm/yr -1 mm/yr -4 mm/yr -9 mm/yr Legend East Velocity (mm/yr)
  15. 15. Temporal span: 10/01/07- 05/06/10 22 images ALOS Mean Ground Velocity Map (LoS) Processed with SARscape
  16. 16. What ALOS can detect 2 1 2007-2010 1992-2010 1 N S S W E 2
  17. 17. COSMO-SkyMed Ground Velocity map (LoS) Ascending orbit 1 2 Area 1 1st of October, 2009: Mud landslide, 30 casualties 1 1 2 2
  18. 18. The April 6, 2009 L’Aquila earthquake Co-seismic & post-seismic phase
  19. 19. Co-seismic deformation maps: first clear SAR interferogram (ENVISAT desc) -27 cm LoS displacement
  20. 20. Co-seismic deformation maps: second clear SAR interferogram (COSMO asc) -25 cm LoS displacement
  21. 21. Co-seismic deformation maps: vertical ground displacement
  22. 22. Co-seismic deformation maps: East ground displacement
  23. 23. The L’Aquila case <ul><li>Descending Orbit </li></ul><ul><li>52 images ( Envisat ) </li></ul><ul><li>From February,2003 to July, 2010 </li></ul><ul><li>135 interferograms </li></ul><ul><li>Ascending Orbit </li></ul><ul><li>34 images ( Envisat ) </li></ul><ul><li>From September, 2003 to June, 2010 </li></ul><ul><li>91 interferograms </li></ul>
  24. 24. Descending Pass Ascending Pass 26/02/2003- 14/07/2010 02/09/2003- 22/06/2010 ASAR Mean Velocity Map (LoS) earthquake
  25. 25. ALOS Mean Velocity Map (LoS) Track 639 Frame 830 Temporal span: 15/01/2007-26/07/2010 Processed with SARscape 16 images
  26. 26. Temporal span: 29/04/2009-13/10/2009 23 slc used Ascending Orbit COSMO-SkyMed Mean Ground Velocity Map (LoS) Processed with SARscape earthquake earthquake
  27. 27. COSMO-SkyMed Displacement Map (LoS)
  28. 28. Conclusions <ul><li>Multitemporal InSAR techniques are able to measure the ground deformation related to the seismic cycle, down to 1 mm/yr (inter-seismic phase); </li></ul><ul><li>In our setting we find that, for the measurements of low-level inter-seismic deformation, the C Band is the best suited, while the X Band is too subject to temporal decorrelation, and the L band lacks sensitivity; </li></ul><ul><li>The post-seismic trends are best measured using X band data (higher resolution); </li></ul><ul><li>All SAR systems used are well suited for co-seismic deformation mapping, although shorter revisit intervals (2-3 days) are needed for fully operational applications; </li></ul><ul><li>Continuity of data acquisition and archival is needed to effectively measure the long-term deformation associated to the seismic cycle; </li></ul><ul><li>Using images from different sensors (C, L, X band) in a synergistic way, allows cross-validation and more significant results. </li></ul>Acknowledgements: Dr. Paolo Riccardi, Dr. Alessio Cantone (SARMAP); Dr. Simona Zoffoli, Italian Space Agency.
  29. 29. Thank you for your attention!

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