solaro_igarss_2011.ppt

2011 IEEE International Geoscience and Remote Sensing Symposium- 24-29 July,Vancouver, Canada2011 IEEE International Geoscience and Remote Sensing Symposium- 24-29 July,Vancouver, Canada

SBAS-DInSAR time series in the last eighteen years at Mt. Etna volcano (Italy)

G. SOLAROG. SOLARO11, , F. CASUF. CASU11, , L. PAGLIA11, A. PEPE1 , S. PEPE11, E. SANSOSTIE. SANSOSTI11, , P. TIZZANI11, R. LANARI11

1. IREA – CNR, Naples (Italy)


SummarySummary

We investigate deformation phenomena affecting We investigate deformation phenomena affecting Mt. Etna Mt. Etna by by exploiting the exploiting the Small BAseline Subset (SBAS)Small BAseline Subset (SBAS) technique that technique that permits permits to produce mean deformation maps and time series to produce mean deformation maps and time series relevant to large areas obtained by using relatively relevant to large areas obtained by using relatively low resolution low resolution DInSAR interferogramsDInSAR interferograms..

We present first preliminary We present first preliminary COSMO-SkyMed results (2009-2010 time interval) in term of spatial and temporal deformation..

We benefit from the availability of ERS-ENVISAT multi-orbit (ascending and descending) data in order to discriminate the vertical and East-West components of the volcano edifice displacements and generate the relevant time series.


SBAS-DInSAR algorithm: key aspects

To produce deformation times-series from a SAR dataset, the SBAS approach:

properly “links” the interferometric SAR data subset (if present) separated by large baselines (the SVD method is applied).

exploits interferograms characterized by a “small baseline” in order to mitigate decorrelation phenomena;

“merging” SAR data acquired by different sensors with the same illumination geometry, as for the case of ERS-1/2 and ENVISAT IS2.

Achieved accuracies:• ≈ 1 - 2 mm/year on the mean deformation velocity• ≈ 5 - 10 mm on the single displacement

ERSERS

ERSERS

ERSERS

ERSERS

ERSERS

ENVISAENVISATT

ENVISAENVISATT


Multi-sensor SBAS analysisMulti-sensor SBAS analysis

Subset 2Subset 2(ENVISAT)(ENVISAT)

TimeTime

Per

pen

dic

ula

r P

erp

end

icu

lar

Bas

elin

eB

asel

ine

Subset 1Subset 1(ERS)(ERS)

The SBAS approach : The SBAS approach :

allows usallows us to exploit SAR data acquired by different sensors with to exploit SAR data acquired by different sensors with the the same illumination geometry, same illumination geometry, as for the case of ERS-1/2 and as for the case of ERS-1/2 and ENVISAT IS2;ENVISAT IS2;

avoids the use of avoids the use of cross-sensor interferogramscross-sensor interferograms;;

combines the ERS-ERS and ENVISAT-ENVISAT interferograms combines the ERS-ERS and ENVISAT-ENVISAT interferograms by applying the by applying the basic rationale of the techniquebasic rationale of the technique..


3 radialRift zones

STRUCTURE OF ETNA

Pernicana + Ragalna:boundaries of

collapsing sector


ERS - ENVISAT data set

Sensors: ERS - ENVISAT

•120 descending orbit88 ERS, 37 ENV347 Interferograms

•139 ascending orbit94 ERS, 53 ENV372 Interferograms

Time span: 1994-2008


We use two different strategies analysis

Cumulative displacements and deformation time series analysis

2000-2003 time interval = non-linear deformation

1994-2000 and 2003-2008 time interval = linear trend of deformation

deformation velocity analysis

Our goal is to provide an interplay between surface volcano deformation and volcanic activity


Etna SAR Velocity maps

We analysed the 1994-2000 and 2003-2008 time interval because

of their linear behaviour of

deformation trend


Eastern flank velocity profiles analysis

There is a general correspondence between the discontinuities in velocity and active faults confirming that the known faults are active during 1994-2008


Eastern flank histograms velocity analysis

Sectors 2,6,7 and 8 show narrower histograms with a clear peak indicating a homogeneous ew velocity and a rigid behaviour of that block


Weastern flank velocity profiles analysis

This flank conists of three main blocks


Weastern flank histograms velocity analysis

Sectors 9 and 10 are in part kinematically distinct both moving toward west


Deformation between 2000-2003 (1)


Deformation between 2000-2003 (2)


Three main processes affecting the observed volcano deformation

Solaro et al. (2010) Journal of Geophysical Research vol. 115, B10405, 2010.


COSMO-SkyMed resultsM

ean

velo

city

[cm

/yr]

> 5

<-5

Mean deformation velocity map

Orbit:descending

Band X ( = 3.1 cm)

Resolution: 25x25m

Time interval: July 2009 – December 2010

COSMO-SkyMed: 8 days

ENVISAT: 35 days


Mea

n ve

loci

ty [

cm/y

r]

> 5

<-5

Pernicana Fault

COSMO-SkyMed results

Mean deformation velocity map

Orbit:descending

Band X ( = 3.1 cm)

Resolution: 25x25m

Time interval: July 2009 – December 2010


Direzione di vista

Direzione di volo

Atmosphericnoise

30/03/2010 - 07/04/2010; spatial baseline : 133 m

M=3.6 eqk occurred on April

3rd 2010


COSMO-SkyMed – ENVISAT comparisonM

ean

velo

city

[cm

/yr]

> 5

<-5


COSMO-SkyMed – ENVISAT comparisonM

ean

velo

city

[cm

/yr]

> 1.5

<-1.5


COSMO-SkyMed – ENVISAT comparison

COSMO-SkyMed ENVISAT

Revisiting time: 8 days

Period: July 2009 – December 2010

Band X ( = 3.1 cm)

Resolution: 25 x 25 meters

Revisiting time : 35 days

Period: 1992 – 2010

Band C ( = 5.6 cm)




Period: 1992 – 2010

Band C ( = 5.6 cm)


Confronto COSMO-SkyMed - ENVISAT: Etna

COSMO-SkyMed ENVISAT


Period: July 2009 – December 2010

Band X ( = 3.1 cm)

Resolution: 25 x 25 metri


COSMO-SkyMed – ENVISAT comparison

COSMO-SkyMed

ENVISAT

M=3.6 eqk occurred on April

3rd 2010


CSK notesCSK notes

It is clearly visible how the 8 (and 4)-days COSMO-SkyMed repeat pass permits to better detect and model the ongoing deformation with respect to the 35-days ENVISAT data. Indeed, for instance, we can appreciate the jump due to the M=3.6 April 3rd, 2010 earthquake

It is evident the increased spatial density of the COSMO-SkyMed measurements with respect to the ENVISAT ones

Using of X-band data sensor for volcano monitoring and Civil Protection purposes


THANKS!!

solaro_igarss_2011.ppt

Technology

case of ers

envisatenvisat interferograms

sbasdinsar time series

theground deformation

deformation timesseries

temporal deformation

time series relevant

relevant time series