Istituto Nazionale di Geofisica e Vulcanologia
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
Istituto Nazionale di Geofisica e Vulcanologia
1. Processes of the seismic cycle. 2. Earthquake interaction.
3. Earthquake preparation processes.
4. Earthquake-induced hazards.
Some challenges in tectonics and earthquake science
Istituto Nazionale di Geofisica e Vulcanologia
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
Istituto Nazionale di Geofisica e Vulcanologia
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
Istituto Nazionale di Geofisica e Vulcanologia
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.
Istituto Nazionale di Geofisica e Vulcanologia
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.
1 23
Istituto Nazionale di Geofisica e Vulcanologia
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.
1 2 3
Atzori et al., 2012
Main requirement: ad hoc acquisitions on post seismic phase
Istituto Nazionale di Geofisica e Vulcanologia
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
Istituto Nazionale di Geofisica e Vulcanologia
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 Radarsat interferogram 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 eventsCSK 2nd event
- =Courtesy of TRE
Istituto Nazionale di Geofisica e Vulcanologia
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
=Pezzo et al., 2012
Main requirement: temporally dense monitoring (days)
Istituto Nazionale di Geofisica e Vulcanologia
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
Istituto Nazionale di Geofisica e Vulcanologia
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.
Istituto Nazionale di Geofisica e Vulcanologia
4 – Earthquake induced hazards
Local gravitational deformation triggered by L’Aquila eq.
~5 cm displacement triggered by the earthquake on ancient slope deformations
AA
BBCC
Major trench zone
A BC
Moro et al., 2011
Main requirement: high spatial resolution data
(and comparable resolution DEM)
Istituto Nazionale di Geofisica e Vulcanologia
1.EO data acquisition
2.EO data access
3.EO data analysis and information retrieval
Some requirements and recommendations for EO data exploitation – Earthquakes and Tectonics
Istituto Nazionale di Geofisica e Vulcanologia
Scientific User’s requirements:
1 - EO data acquisition
1. long term mission continuity2. stable sensor characteristics and acquisition geometries3. community interaction with Agencies for site selection4. flexibility of acquisition geometry for shorter monitoring periods (e.g.
post-seismic phase)5. large swaths and medium resolution (some applications)6. high resolution EO data and DEMs (other applications)
Istituto Nazionale di Geofisica e Vulcanologia
Possible actions:
1 - EO data acquisition
1. Integrated (and cooperative) long term global observation strategy2. Synergetic use of different missions (e.g. to make up for variable
spatial/temporal resolution and coverage gaps)3. Intelligent resource management (different spatial/temporal sampling
can be used on different areas, e.g. InSAR over Emilia vs Dead Sea)
Problems:
1. loss of monitoring continuity (change of sensor/platform)2. conflicting requirements (high/low resolutions)3. conflicting acquisition requests (science/commercial/operation/defense)
Istituto Nazionale di Geofisica e Vulcanologia
Scientific User’s requirements:
2 - EO data access
1. data at no cost2. standard interfaces for data access (across missions)3. standardisation of formats (across missions)4. short access time
Istituto Nazionale di Geofisica e Vulcanologia
Possible actions:
2 - EO data access
1. inter-agency agreements for cost reduction2. direct satellite download3. provide remote processing capability to scientific community (e.g.
GPOD)4. harmonisation of formats and interfaces/procedures for data access
Problems:
1. costly data for some missions2. delays in image availability3. too many different formats4. different data access procedures and interfaces
Istituto Nazionale di Geofisica e Vulcanologia
Scientific User’s requirements:
3 - EO data analysis and information retrieval
1. funding for research projects2. EO results validation3. access to image processing tools4. specific high level knowledge and processing resources
Istituto Nazionale di Geofisica e Vulcanologia
Possible actions:
1. fund permanent training (and mobility) for Earth scientists2. fund high level university education3. provide free knowledge and technical help to the community (remote
processing, help desk on specific applications) 4. issue scientific research calls, also coordinated among different
Agencies5. stimulate community building
Problems:
1. knowledge gap between development of EO technology and Earth scientists (especially in underdeveloped countries)
2. also, shortage of human and technical resources limits the diffusion of EO data use in many disciplines
3. difficult access to validation data for error estimation (either previous EO results or in situ data)
3 - EO data analysis and information retrieval