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Eruptive cycles inferred from ground deformation at Piton de La Fournaise - A case study for the GlobVolcano project -. A. Peltier 1 , E. Kaminski 2 , JC. Komorowski 1. with contributions from T. Staudacher, M. Bianchi. - PowerPoint PPT Presentation
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Eruptive cycles inferred from ground
deformation at Piton de La Fournaise
- A case study for the GlobVolcano project -
A. Peltier1, E. Kaminski2, JC. Komorowski1
with contributions from T. Staudacher, M. Bianchi
1. Equipe de Géologie des systèmes volcaniques, Institut de Physique du Globe de Paris (IPGP), France2. Equipe de Dynamique des fluides géologiques, IPGP
Indian Ocean
130 150 170
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190
Geological Setting
(Gauss Laborde Réunion Coordinates, km)
Piton de La Fournaise
Introduction - GPS data - PSInSAR - Conclusion
Since 1998 : 26 eruptions
2 eruptions per year
rest
rest
Number of eruptions per year
130 150 170
(Gauss Laborde Réunion Coordinates, km)
20
40
60
30
50
70
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Rest Periods : 1966-1972, 1992-1998
Eruptive Activity
Piton de La Fournaise
Introduction - GPS data - PSInSAR - Conclusion
Distal eruptions
Proximal eruptions
Summit eruptions
Eruptive fissures : 1998-2007
Introduction - GPS data - PSInSAR - Conclusion
Proximal eruption
Distal eruption
Summit eruption
1000
2000
Elevation (m)
01-jan-00 01-jan-02 01-jan-04 01-jan-06
Eruptive cycles
Elevation of eruptive fissures
(Peltier et al., in press, JVGR)
176000 178000 180000 182000
34000
36000
38000
40000
Extensometer network
Tiltmeter network
Continuous GPS network
(since 2004)
Deformation network
DolomieuBory
Introduction - GPS data - PSInSAR - Conclusion
Projet GlobVolcanoPiton Bien car bcp d’éruption et permetDe valider les données avec les field data
Good case study for the GlobVolcano project
Piton de La Fournaise:
• High eruptive activity
• Well monitored with ground deformation network
Introduction - GPS data - PSInSAR - Conclusion
Projet GlobVolcanoPiton Bien car bcp d’éruption et permetDe valider les données avec les field data
Introduction - GPS data - PSInSAR - Conclusion
Validation of deformation mapping products
Piton de La Fournaise:
• High eruptive activity
• Well monitored with ground deformation network
(Peltier, 2007)
GPS data (2004-2007)
Introduction - GPS data - PSInSAR - Conclusion
NS component
EW component
Introduction - GPS data - PSInSAR - Conclusion
Short-term eruptive displacements(up to 20×103 mm d-1)
(Peltier, 2007)
GPS data (2004-2007)
NS component
EW component
Introduction - GPS data - PSInSAR - Conclusion
Short-term eruptive displacements(up to 20×103 mm d-1)
Horizontal displacements Vertical displacements
Horizontal displacements Vertical displacements
(1)
(2)
(1) (2)
(Peltier, 2007)
GPS data (2004-2007)
NS component
EW component
Introduction - GPS data - PSInSAR - Conclusion
Short-term eruptive displacements(up to 20×103 mm d-1)
(1)
ΔP = 2.2 MPa Explained data: 89% (1)
(Peltier et al. 2008, EPSL)
GPS data (2004-2007)
NS component
EW component
Introduction - GPS data - PSInSAR - Conclusion
Short-term eruptive displacements(up to 20×103 mm d-1)
(1)
GPS data (2004-2007)
(Peltier et al. in press, JVGR)
NS component
EW component
GPS data (2004-2007)
Pre-eruptive long term inflation (0.4-0.7 mm d-1)
Introduction - GPS data - PSInSAR - Conclusion
NS component
EW component
(Peltier et al. in press, JVGR)
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
GPS ↔ available data for the PSInSAR product validation.
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
GPS ↔ available data for the PSInSAR product validation.
1st stage: identify time periods with a continuous GPS record.
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
BORg
SNEg
DSRg
Introduction - GPS data - PSInSAR - Conclusion
GPS ↔ available data for the PSInSAR product validation.
1st stage: identify time periods with a continuous GPS record.
5 GPS stations with a continuous record between April 2004 and March 2007: - 3 at the summit BORg, DSRg, SNEg - 2 reference stations, outside of the summit cone.
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
GPS ↔ available data for the PSInSAR product validation.
1st stage: identify time periods with a continuous GPS record.
5 GPS stations with a continuous record between April 2004 and March 2007: - 3 at the summit BORg, DSRg, SNEg - 2 reference stations, outside of the summit cone.
GPS positions over S2 PS results (2004-2007)
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
GPS ↔ available data for the PSInSAR product validation.
1st stage: identify time periods with a continuous GPS record.
5 GPS stations with a continuous record between April 2004 and March 2007: - 3 at the summit BORg, DSRg, SNEg - 2 reference stations, outside of the summit cone.
(M. Bianchi)
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
January 2004 distal
eruption
BORg station
PS time series, DSRg station
Introduction - GPS data - PSInSAR - Conclusion
2nd stage : find the longest time period with no eruption disturbing both the GPS and the PSInSAR records.
the selected period ranges between March and October 2005. Two distinct deformation phases can be identified : (1) from March to July
(2) from July to October
Validation of deformation mapping products (PSInSAR)
Introduction - GPS data - PSInSAR - Conclusion
To avoid the lack of coherency between images used to compute the interferograms, we focused on the pre-eruptive unrest periods.
Validation of deformation mapping products (PSInSAR)
2nd stage : find the longest time period with no eruption disturbing both the GPS and the PSInSAR records.
the selected period ranges between March and October 2005. Two distinct deformation phases can be identified : (1) from March to July
(2) from July to October
Estimates of displacement rates in the line of sight of the satellite as inferred from the PSInSAR time series.
Estimates of GPS displacement rates in the line of sight of the satellite as inferred from the PSInSAR time series.
Introduction - GPS data - PSInSAR - Conclusion
To avoid the lack of coherency between images used to compute the interferograms, we focused on the pre-eruptive unrest periods.
Good agreement between the two methods, within their associated error bars
Introduction - GPS data - PSInSAR - Conclusion
Comparison between PSInSAR and GPS data
Good agreement between the two methods, within their associated error bars
Introduction - GPS data - PSInSAR - Conclusion
Comparison between PSInSAR and GPS data
For the pre-eruptive unrest periods :
Good agreement between the PSInSAR and GPS data : PSInSAR data provide global
inference of the ground deformation field
PSInSAR data : useful complementary information for accurate ground displacement mapping
GPS data : Two time scales of ground deformation
(1) Large short-term ground displacements (up to 20×103 mm d-1), a few min to hours
prior each eruption
(2) Small long-term ground displacements during pre-eruptive unrest (0.4-0.7 mm d-1
of summit inflation)
Introduction - GPS data - PSInSAR - Conclusion
Conclusion – Ground deformation mapping product
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36000
38000
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DolomieuBory
Perspectives
PSInSAR at Piton de La Fournaise
• Complementary to GPS data
GPS data: dynamics of the ground deformation in real-time
PSInSAR data: cover a larger area
Introduction - GPS data - PSInSAR - Conclusion
Introduction - GPS data - PSInSAR - Conclusion
176000 178000 180000 182000
34000
36000
38000
40000
DolomieuBory
Distal eruptions
Perspectives
PSInSAR at Piton de La Fournaise
• Complementary to GPS data
Notably for the distal eruptions
located outside of the summit cone
where no field monitored networks are
implemented
Introduction - GPS data - PSInSAR - Conclusion
176000 178000 180000 182000
34000
36000
38000
40000
DolomieuBory
Distal eruptions
Perspectives
PSInSAR at Piton de La Fournaise
• Support to early stage warning of
volcanic risk especially during distal
eruptions.
Introduction - GPS data - PSInSAR - Conclusion
Product Validation at Piton de La Fournaise
Ground deformation mapping
Surface thermal anomalies
Introduction - GPS data - PSInSAR - Conclusion
Other product validation : Surface thermal anomalies (ASTER-SPOT-MODIS)
Results of the validation
September 2006 - January 2007 eruption
GlobVolcano mass flux is about 30% larger than the volumetric flux measured by the observatory.
This implies an average porosity of about 30% for the lava flow, which agrees with both literature reference and some measurements made by the observatory.
MODIS MIR- saturationMODIS MIR- saturation
(B. Hirn)
Introduction - GPS data - PSInSAR - Conclusion
Other product validation : Surface thermal anomalies (ASTER-SPOT-MODIS)
Increase of surface activity linked with the summit crater collapse: flux estimated at > 50m3/s on the field
Introduction - GPS data - PSInSAR - Conclusion
Other product validation : Surface thermal anomalies (ASTER-SPOT-MODIS)
Projet GlobVolcanoPiton Bien car bcp d’éruption et permetDe valider les données avec les field data
Product validation at Piton de La Fournaise:
Introduction - GPS data - PSInSAR - Conclusion
• Ground deformation mapping
• Surface thermal anomalies
- Remarkable agreement found between ground data and GlobVolcano product.
- Both the location of the eruptive center, the emplacement of active lava flow, the
ground displacements and the eruptive mass flux appear as robust and as accurate as
the observatory record.
THANKS for your attention !!!
