IGARSS 2011 – July, Vancouver, Canada 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

IGARSS 2011 – July, Vancouver, Canada Outline 1.The SIGRIS Project (funded by Italian Space Agency): exploiting Earth Observation data for seismic risk management 2.SAR data processed and DInSAR techniques used 3.The Straits of Messina and the L’Aquila cases 4.Conclusions Further information:

IGARSS 2011 – July, Vancouver, Canada Two operations mode To generate EO-based, value-added products for the operational use by the National Civil Protection Service in two risk management phases: 1.Knowledge & Prevention, i.e. support to the Seismic Hazard assessment 2.Warning & Crisis, i.e. support to the Emergency management 1.During normal routine operations, the products for the Knowledge & Prevention (i.e. support to Seismic Hazard Assessment), are generated 2.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 To identify factors limiting the EO data exploitation

IGARSS 2011 – July, Vancouver, Canada 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.

IGARSS 2011 – July, Vancouver, Canada What data we use SAR data Same viewing geometry (interferometric acquisitions) From ascending and descending passes Consistent datasets (15-20 images minimum) 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) CGPS data Site displacement time series for the 3 cartesian components Minimum 3 stations per SAR coverage for a correct SAR-GPS integration To estimate and remove possible ramps  X-Band: Cosmo-SkyMed (April, >), asc-desc  C-Band: ERS1/2 ( ), asc-desc ENVISAT ( ), asc-desc  L-Band: ALOS (2007->), asc

IGARSS 2011 – July, Vancouver, Canada DInSAR techniques We use multitemporal InSAR techniques:  SBAS-Small BAseline Subset (IREA-CNR), SARscape (Sarmap);  Permanent Scatterers (T.R.E.,Milano). We validate the result using:  CGPS  levelling lines  Geological and seismological data. 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. Ferretti, A., C. Prati, and F. Rocca (2001), Permanent scatterers in SAR interferometry, IEEE Trans. Geosci. Remote Sens., 39(1), 8– 20.

IGARSS 2011 – July, Vancouver, Canada 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.

IGARSS 2011 – July, Vancouver, Canada 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

IGARSS 2011 – July, Vancouver, Canada Ground deformation using time-series DInSAR SAR Data: ERS ( ) 71 images (D), 37 (A) ENVISAT ( ) 34 images (A) ALOS ( ) 22 images (A) COSMO-Skymed ( ) 17 images (D)

IGARSS 2011 – July, Vancouver, Canada Mean Ground Velocity Maps (LoS) Ascending Orbit Descending orbit ERS+ENVISAT

IGARSS 2011 – July, Vancouver, Canada Time Series examples

IGARSS 2011 – July, Vancouver, Canada Up & East Velocity Maps Up Component East Component look angle = variable along the swath We constrained the SAR North component based on the CGPS one.

IGARSS 2011 – July, Vancouver, Canada Up Component _ + 2 mm/yr 0 mm/yr -2 mm/yr 3 mm/yr 1.5 mm/yr -0.5 mm/yr Legend Up Velocity (mm/yr)

IGARSS 2011 – July, Vancouver, Canada 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)

IGARSS 2011 – July, Vancouver, Canada Temporal span: 10/01/07- 05/06/10 22 images ALOS Mean Ground Velocity Map (LoS) Processed with SARscape

IGARSS 2011 – July, Vancouver, Canada What ALOS can detect N S S W E

IGARSS 2011 – July, Vancouver, Canada COSMO-SkyMed Ground Velocity map (LoS) Ascending orbit Area 1 1st of October, 2009: Mud landslide, 30 casualties

IGARSS 2011 – July, Vancouver, Canada The April 6, 2009 L’Aquila earthquake Co-seismic & post-seismic phase

IGARSS 2011 – July, Vancouver, Canada Co-seismic deformation maps: first clear SAR interferogram (ENVISAT desc) -27 cm LoS displacement

IGARSS 2011 – July, Vancouver, Canada Co-seismic deformation maps: second clear SAR interferogram (COSMO asc) -25 cm LoS displacement

IGARSS 2011 – July, Vancouver, Canada Co-seismic deformation maps: vertical ground displacement

IGARSS 2011 – July, Vancouver, Canada Co-seismic deformation maps: East ground displacement

IGARSS 2011 – July, Vancouver, Canada The L’Aquila case Descending Orbit 52 images (Envisat) From February,2003 to July, interferograms Ascending Orbit 34 images (Envisat) From September, 2003 to June, interferograms

IGARSS 2011 – July, Vancouver, Canada Descending Pass Ascending Pass 26/02/ /07/ /09/ /06/2010 ASAR Mean Velocity Map (LoS) earthquake

IGARSS 2011 – July, Vancouver, Canada ALOS Mean Velocity Map (LoS) Track 639 Frame 830 Temporal span: 15/01/ /07/2010 Processed with SARscape 16 images

IGARSS 2011 – July, Vancouver, Canada Temporal span: 29/04/ /10/ slc used Ascending Orbit COSMO-SkyMed Mean Ground Velocity Map (LoS) Processed with SARscape earthquake

IGARSS 2011 – July, Vancouver, Canada COSMO-SkyMed Displacement Map (LoS)

IGARSS 2011 – July, Vancouver, Canada Conclusions  Multitemporal InSAR techniques are able to measure the ground deformation related to the seismic cycle, down to 1 mm/yr (inter-seismic phase);  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;  The post-seismic trends are best measured using X band data (higher resolution);  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;  Continuity of data acquisition and archival is needed to effectively measure the long-term deformation associated to the seismic cycle;  Using images from different sensors (C, L, X band) in a synergistic way, allows cross-validation and more significant results. Acknowledgements: Dr. Paolo Riccardi, Dr. Alessio Cantone (SARMAP); Dr. Simona Zoffoli, Italian Space Agency.

IGARSS 2011 – July, Vancouver, Canada Thank you for your attention!