SCIENTIFIC EXPLOITATION OF EO DATA FOR EARTHQUAKES AND TECTONICS

1. SCIENTIFIC EXPLOITATION OF EO DATA FOR EARTHQUAKES AND TECTONICS Stefano Salvi National Earthquake CenterIstituto Nazionale di Geofisica e Vulcanologia - Roma Models for scientific exploitation of EO Data – ESA-ESRIN 11-12 Oct. 2012

2. Processes of the seismic cycle. Earthquake interaction. Earthquake preparation processes. Earthquake-induced hazards. Some challenges in tectonics and earthquake science

3. 1 – Processes of the seismic cycle Long term monitoring of crustal strain before and after an earthquake is necessary to understand the large scale processes that bring tectonic stresses to rupture the crust and cause earthquakes, and to understand the rheology of the lower crust and upper mantle. EO contributing data: SAR , CGPS. Main requirement: long term monitoring continuity

4. 2 - Earthquake interaction Temporally dense geodetic time series are needed to investigate the effects of stress redistribution after large earthquakes, and the possible implications for the triggering of large earthquakes on nearby faults. EO contributing data: SAR, CGPS

5. 2 - Earthquake interaction The 2010-2011 New Zealand seismic sequence The Mw 7.1 Darfield mainshock was followed by 5 more Mw > 6 events, occurring during 1.5 years, along an E-W alignment.

6. 2 - Earthquake interaction The 2010-2011 New Zealand seismic sequence Using ENVISAT, ALOS, and COSMO-SkyMed data, and InSAR, and offset tracking techniques, the ground deformation of three of the seismic sources was measured and then modeled. 2 1 3

7. 2 - Earthquake interaction The 2010-2011 New Zealand seismic sequence The earthquakes had a clear interaction: the first earthquake increased the stress level on the faults of the second earthquake, and together they increased the stress level on the fault of the third event. Main requirement: ad hoc acquisitions on post seismic phase 2 3 1 Atzori et al., 2012

8. Monitoring geophysical and geochemical parameters over tectonically active areas in many different geological environments, with high spatial and temporal resolution and accuracy, might unveil important phenomena which are thought to occur during the earthquake preparation phases, at medium to short timescales. EO contributing data: SAR , CGPS, thermal IR, electromagnetic. 3 - Earthquake preparation processes

9. During the Emilia seismic sequence, the M 5.9 mainshock was followed, 9 days later, by an M 5.8 aftershock. We subtracted from a Radarsatinterferogram containing the total ground deformation of the two events, a COSMO-SkyMed interferogram containing the deformation due to the second event only. They have the same LoS. 3 - Earthquake preparation processes Deformation transient before the M 5.8 Emilia earthquake Rsat all events CSK 2nd event - = Courtesy of TRE

10. We thus obtain the ground deformation occurred just before the second earthquake. Besides the clear co-seismic pattern of the mainshock, a further deformation pattern become evident (black circle). There is apparently no comparable size aftershock connected to such signal, which in fact is well explained by foreslip on the same fault plane which later originated the M 5.8 aftershock. 3 - Earthquake preparation processes Deformation transient before the M 5.8 Emilia earthquake Main requirement: temporally dense monitoring (days) = Pezzo et al., 2012

11. Earthquake ground shaking and stress transfer may trigger a number of geological effects which increase the co-seismic and post-seismic hazard, e.g. Volcanic eruptions, tsunamis, gravitational sliding, surface faulting and collapse, soil liquefaction, soil gas release, etc. EO sensors can provide important information to understand the details of some of these effects and their driving processes. EO contributing data: SAR , CGPS, optical, thermal, electromagnetic. 4 – Earthquake induced hazards

12. Several such effects are well mapped by the 5 m resolution COSMO interferogram 4 – Earthquake induced hazards Local gravitational deformation triggered by L’Aquila eq.

13. 4 – Earthquake induced hazards Local gravitational deformation triggered by L’Aquila eq. ~5 cm displacement triggered by the earthquake on ancient slope deformations Major trench zone A Main requirement: high spatial resolution data (and comparable resolution DEM) B C B A C Moro et al., 2011

14. EO data acquisition EO data access EO data analysis and information retrieval Some requirements and recommendations for EO data exploitation – Earthquakes and Tectonics

15. Scientific User’s requirements: 1 - EO data acquisition • long term mission continuity • stable sensor characteristics and acquisition geometries • community interaction with Agencies for site selection • flexibility of acquisition geometry for shorter monitoring periods (e.g. post-seismic phase) • large swaths and medium resolution (some applications) • high resolution EO data and DEMs (other applications)

16. Possible actions: 1 - EO data acquisition Problems: • loss of monitoring continuity (change of sensor/platform) • conflicting requirements (high/low resolutions) • conflicting acquisition requests (science/commercial/operation/defense) • Integrated (and cooperative) long term global observation strategy • Synergetic use of different missions (e.g. to make up for variable spatial/temporal resolution and coverage gaps) • Intelligent resource management (different spatial/temporal sampling can be used on different areas, e.g. InSAR over Emilia vs Dead Sea)

17. Scientific User’s requirements: 2 - EO data access • data at no cost • standard interfaces for data access (across missions) • standardisation of formats (across missions) • short access time

18. Possible actions: 2 - EO data access Problems: • costly data for some missions • delays in image availability • too many different formats • different data access procedures and interfaces • inter-agency agreements for cost reduction • direct satellite download • provide remote processing capability to scientific community (e.g. GPOD) • harmonisation of formats and interfaces/procedures for data access

19. Scientific User’s requirements: 3 - EO data analysis and information retrieval • funding for research projects • EO results validation • access to image processing tools • specific high level knowledge and processing resources

20. Possible actions: 3 - EO data analysis and information retrieval Problems: • knowledge gap between development of EO technology and Earth scientists (especially in underdeveloped countries) • also, shortage of human and technical resources limits the diffusion of EO data use in many disciplines • difficult access to validation data for error estimation (either previous EO results or in situ data) • fund permanent training (and mobility) for Earth scientists • fund high level university education • provide free knowledge and technical help to the community (remote processing, help desk on specific applications) • issue scientific research calls, also coordinated among different Agencies • stimulate community building

21. Thank you for your attention and a special thank to Gemma Manoni – ASI for the fruitful discussions