Uncovering deformation processes from space
Stramondo S.1, Albano M.1, Bignami C.1, Cannelli V.1, Moro M.1, Melini D.1,
Polcari M.1, Saroli M.1,2, Trasatti E.1
1 Istituto nazionale di Geofisica e Vulcanologia, Italy
2 University of Cassino and Southern Lazio, Dept. of Civil and Mechanical Eng., Italy
Outline
- Surface movements: Natural and/or Man Made
- Measure surface movements from Space: How?
When? Where?
- InSAR: improvements on Science and Technology
- The way forward
Surface movements: Natural and/or
Man Made
•
Seismology
- Seismic cycle (co-seismic, post-seismic, interseismic
displacements)
- Aseismic
•
Volcanology
- unrest, pre-eruptive and eruptive volcano dynamics
•
Subsidence
- fluid extraction (agriculture, industry, gas storage, …)
- soil compaction due to urban expansion
- mining activities, nuclear tests
Measure surface movements from
Space: How? When? Where?
- Satellite Synthetic Aperture Radar (SAR) is a “remote” tool for
measuring parameters at Earth surface
- SAR is weather and time indipendent
4
Measure surface movements from
Space: How? When? Where?
-Interferometric SAR (InSAR) technique measures the pixel to
pixel phase difference between two SAR images of the same
scene viewed from comparable geometries.
S1  A1e
 j1
S 2  A2e
 j 2
 A1e
j
 A2e
4

j
r1
4

Antenna 2
r2
Antenna 1
Bp
Bn
r2
Interferogram

S1S 2  A1 A2e
j
4

h
( r1  r2 )
r1
Measure surface movements from
Space: How? When? Where?
Gabriel, A.K., Goldstein, R.M., Zebker, H.A., 1989. Mapping small elevation changes over large areas: differential
radar interferometry. J. Geophys. Res., 94 (B7), pp. 9183-9191.
6
Measure surface movements from
Space: How? When? Where?
Massonnet
Massonnetetetal.,
al.,1993
1995
Measure surface movements from
Space: How? When? Where?
from B. Parsons, Santorini Forum, May 2012
1992-2013 about 100 earthquakes studied with InSAR
Measure surface movements from
Space: How? When? Where?
from G. Puglisi, Santorini Forum, May 2012
Measure surface movements from
Space: How? When? Where?
from G. Puglisi, Santorini Forum, May 2012
1992-2012 active volcanoes surveyed ERS, Envisat, JERS, ALOS
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
- SAR satellite sensors: from medium to VH resolution
- SAR satellite missions: from single satellite toward constellations
- SAR satellite wavelenght: from C-, to C-L-, to X-C-L-Band
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
-SBAS-Small Baseline Subsets [Berardino et al., 2002]; [R Lanari et al., 2004])
- CPT-Coherent Point Targets [Mora et al., 2003]
- WabInSAR [Shirzaei, 2012]
- StaMPS [Hooper et al., 2004]
- PS-Permanent Scatterer [A Ferretti et al., 2000]
- IPTA-Interferometric Point Target Analysis [Werner et al., 2003]
- SPN-Stable Point Network [Crosetto et al., 2005]
- pi-rate [Biggs et al., 2007]
InSAR: improvements on Science
and Technology
SBAS - Small BAseline Subsets
PS Permanent scatterers
InSAR: improvements on Science
and Technology
IPTA – interferometric Point Target Analysis
STAMPS – Stanford Method for
Persistent Scatterers
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
From Analytical
models:
Mogi, Okada,
Yang,…
Bignami et al., 2012
InSAR: improvements on Science
and Technology
… toward FEM: geometry
(Pinned Mesh
Perturbation; PMP;
Okmok volcano; 1997
eruption) or the
dynamic parameters Etna
volcano
2002 eruption, 2011
Tohoku-Oki earthquake) of
FEM
models.
Kyriakopoulos et al., 2013
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release,...)
- global surveys
InSAR: improvements on Science
and Technology
- Mw 7.1 Darfield (Canterbury) and Mw 6.3 Christchurch
earthquake (New Zealand, September 2010 and February 2011).
- Complex geometry of Greendale fault retrieved by ALOS
PALSAR; blind thrust fault identified 6 km south-east of
Christchurch centre.
- Non-linear inversion of fault geometry; variable slip
distribution over the fault planes from linear inversion of InSAR.
- Coulomb Failure Function (CFF). The Darfield earthquake
contributed to promote the rupture of the Christchurch fault.
22
InSAR: improvements on Science
and Technology
Stramondo
al., 2011
Elliott et al.,et2012
23
InSAR: improvements on Science
and Technology
Stramondo et al., 2011
24
InSAR: improvements on Science
and Technology
- October 23, 2011 (Mw=7.2), 30 km N of Van city, November
9, 2011 (Mw=5.6) few kilometers to the South, in the Edremit
subprovince.
-Complex geometry of main buried fault. Two subfaults
diverging at depth (dip change) or a single plan with shallower
high dip?
25
InSAR: improvements on Science
and Technology
26
InSAR: improvements on Science
and Technology
27
InSAR: improvements on Science
and Technology
from B. Parsons, Santorini Forum, May 2012
28
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
- Afterslip occurs on the same fault or faults that ruptured during
the earthquake, usually immediately surrounding the rupture
(afterslip usually involve aseismic fault creep).
- Poroelastic rebound is the process of fluid (mostly water) moving
through the pores of rocks due to earthquake pressure changes.
- Viscoelastic relaxation occurs in the upper mantle or lower crust
where the rocks respond to stress changes by viscous flow that
relaxes the applied stress and thus reflects the rheology of rocks at
high temperatures and pressures.
InSAR: improvements on Science
and Technology
Mw 7.6 Manyi earthquake (November 8, 1997)
Ryder et al., 2007
InSAR: improvements on Science
and Technology
Poroelastic rebound model for Track 305.
Evident time series/models discrepancy.
InSAR: improvements on Science
and Technology
Viscoelastic and afterslip models vs time
series Track 305
Maxwell and SLS (Standard Linear Solid)
reology, and afterslip, both can explain the
post-seismic deformation
InSAR: improvements on Science
and Technology
Bam 2003: 3.5 years postseismic observation
Fielding et al., 2009
A1-A2 afterslip
B poroelastic subsidence
C dilatancy recovery
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
- Surface creep in the Parkfield
and Cholame sections. Interseismic
displacement indicates that
tectonic strain was not uniformly
distributed in 1993-2004.
- Creep rate decreases from the
Parkfield section to south (1.4±0.3
cm/yr to 0.6±0.3 cm/yr), a creeprate increase in the Cholame
section (0.2±0.1 cm/yr).
De Michele et al., 2011
The Parkfield section of the
San Andreas Fault (SAF) is
defined as a transitional
portion of the fault between
slip-release behavior types
in the creeping section of
the SAF to the northwest
and the apparently locked
section to the southeast.
InSAR: improvements on Science
and Technology
The InSAR technology:
- Improved performances of satellite missions
- Multitemporal InSAR and Time series
- Modeling algorithms
The knowledge of tectonic processes
- coseismic studies (displacement vs seismic source)
- post-seismic studies (afterslip, poroelastic rebound, ...)
- interseismic studies (low strain release, )
- global surveys
InSAR: improvements on Science
and Technology
Wide Area Processing
Terrafirma ESA Project
InSAR: improvements on Science
and Technology
The knowledge of volcanic processes
- unrest, pre-eruptive and eruptive dynamic studies
- dynamic of tectonic features
- global surveys
InSAR: improvements on Science
and Technology
The knowledge of volcanic processes
- unrest, pre-eruptive and eruptive dynamic studies
- dynamic of tectonic features
- global surveys
InSAR: improvements on Science
and Technology
-Santorini volcano (Greece)
remained dormant since 1950.
- 1992-2010 deflation of Nea
Kameni from SAR time series
(5–6mm/yr) and GPS
-ALOS PALSAR shows the
onset of the phenomenon in
early 2010 (aseismic preunrest, subsidence,1–3 cm,
preceded the uplift)
-2011 March–2012 March
microseismicity and uplift (14
cm/yr according to SAR ts)
Foumelis et al., 2013
InSAR: improvements on Science
and Technology
-Santorini volcano (Greece)
remained dormant since 1950.
- 1992-2010 deflation of Nea
Kameni from SAR time series
(5–6mm/yr) and GPS
-ALOS PALSAR shows the
onset of the phenomenon in
early 2010 (aseismic preunrest, subsidence,1–3 cm,
preceded the uplift)
-2011 March–2012 March
microseismicity and uplift (14
cm/yr according to SAR ts)
InSAR: improvements on Science
and Technology
-Santorini volcano (Greece)
remained dormant since 1950.
- 1992-2010 deflation of Nea
Kameni from SAR time series
(5–6mm/yr) and GPS
-ALOS PALSAR shows the
onset of the phenomenon in
early 2010 (aseismic preunrest, subsidence,1–3 cm,
preceded the uplift
-2011 March–2012 March
microseismicity and uplift (14
cm/yr according to SAR ts)
InSAR: improvements on Science
and Technology
-Santorini volcano (Greece)
remained dormant since 1950.
- 1992-2010 deflation of Nea
Kameni from SAR time series
(5–6mm/yr) and GPS
-ALOS PALSAR shows the
onset of the phenomenon in
early 2010 (aseismic preunrest, subsidence,1–3 cm,
preceded the uplift
-2011 March–2012 March
microseismicity and uplift (14
cm/yr according to SAR ts)
InSAR: improvements on Science
and Technology
Inflation data modelled
by pressurized sources 
of different shapes
•
•
•
•
Results:
Volume variation 7-11 106 m3
Sources located at 3.5 km depth
Sphere and Spheroid show
similar data fit
Differences with observed data
lower than few cm
Sphere
Spheroid
InSAR: improvements on Science
and Technology
- Fast uplift signal stopped before
mid 2012
- Radarsat-2 data covering June 226 2012 measures residual slow
movements
InSAR: improvements on Science
and Technology
In the last years (2011-2013) it has been registered a ground uplift of about 12 cm
We studied this phenomenon using a dataset from Cosmo-SkyMed mission
composed of 40 SAR images spanning May 2011 to March 2013
DATA DESCRIPTION:

Number of interferograms: 28

Maximum perpendicular baseline: 250 meters

Maximum time interval: 80 days

Incidence angle: 27°

Acquisition mode: Stripmap

Multilook factors: 10 x 10

Orbit: Descending
InSAR: improvements on Science
and Technology
The obtained mean
displacement velocity
shows a semicircular
pattern, centered around
the Solfatara area,
characterised by an uplift
peak of about 12 cm/year
in Line of Sight
InSAR: improvements on Science
and Technology
The estimated trend is confirmed by temporal time
series analysis and comparison with GPS data.
For some points located where the uplift peaks
(yellow zone) a significant increase from about mid2012 to March 2013 (last processed image date) can
be noted.
InSAR: improvements on Science
and Technology
Mt. Etna in Sicily, southern Italy, is the largest active volcano in Europe.
It is characterised by several eruptions that continuosly modify the surrounding
area. It undergoes a large deformation during 1993-97, detected by GPS and
DInSAR time series
Trasatti et al., 2009
InSAR: improvements on Science
and Technology
The SE sector of Mt. Etna slides toward the sea and the city of
Catania
Catania
InSAR: improvements on Science
and Technology
Such behavior was also
observed by applying IPTA
processing to L-Band ALOS
PALSAR images spanning
2007-2010
DATA
InSAR: improvements on Science
and Technology
Data modelled by Finite elements with 3D
Topography and elastic heterogeneities
and a pressurized ellipsoid
SAR data helped to constrain
the flank dynamics:
If the sliding of the SE sector
is considered, SAR data are
better reproduced
The ellipsoid is
vertically elongated,
dipping toward
South and Est.
InSAR: improvements on Science
and Technology
The knowledge of volcanic processes
- unrest, pre-eruptive and eruptive dynamic studies
- dynamic of tectonic features
- global surveys
InSAR: improvements on Science
and Technology
Guglielmino et al., 2012
InSAR: improvements on Science
and Technology
The knowledge of volcanic processes
- unrest, pre-eruptive and eruptive dynamic studies
- dynamic of tectonic features
- global surveys
InSAR: improvements on Science
and Technology
> 900 volcanoes surveyed, 4 of which show volcanic
deformations (Pritchard & Simons, 2002, 2004)
The way forward
- Satellite Earth observation (EO) is playing a major role in Earth
Sciences, contributing to the understanding of geophysical phenomena.
- The need to fully exploit EO data lead to develop new algorithms for
data processing and for modeling, and to increase computing capacities
(cloud computing).
- Availability of satellite data with increased spatial (metric or better)
and temporal resolution (constellations? “geostationary SAR”?),
multifrequency systems (X-, C-, L-band).
- Several efforts to coordinate space and in-situ data providers for
selected sites (i.e. Geohazard Supersites) and regions (natural
laboratories for geohazards) in order to make available to the Earth
Science Community.