Advanced interpretation of
PSI time series for mapping and
characterization of geological hazards:
Naro (Italy) case study
C
IGNA
F.
, D
EL
V
ENTISETTE
C., L
IGUORI
V., C
ASAGLI
N.
Terrafirma Workshop
Università degli Studi di Firenze
Department of Civil and Environmental Engineering
Department of Earth Sciences
CENTRE OF COMPETENCE OF THE CIVIL PROTECTION DEPARTMENT
PRESIDENCY OF THE COUNCIL OF MINISTERS
Outline
•
Persistent Scatterer Interferometry
•
Test area: Naro (Italy)
–
Geomorphologic and historical background
–
PSI time series analysis
–
Final results
Persistent Scatterer Interferometry
Multi-image
processing
TI
ME
n
SAR
images
Average LOS deformation rate
(precision ~ 0.1-1 mm/yr)
Displacement time-series
(precision ~ 1-3 mm on single measure)
Identification of potential
anomalies and/or accelerations
d
t
d
t
d
t
Persistent Scatterer Interferometry
Test area: Naro (Italy)
Geomorphologic & historical background
Vanelle St.
Gesù Maria St.
February 4
th
, 2005 event
• Severe ground deformations
• Opening of fractures (aperture up
to 5-10 cm) in buildings and road
infrastructure
• Last documented reactivations:
1997, 1942, 1940, 1934, 1908
Test area: Naro (Italy)
Geomorphologic & historical background
NW view
SE view
Morphologic scarps
Morphologic scarps
W view
First hypotheses
• landslide or tectonics?
Field observations
• NNW-SSE stress distribution
(same as regional tectonics)
• well-marked scarps of probable
Test area: Naro (Italy)
PSI time-series analysis
Vanelle St.
Gesù Maria St.
larger extension of
affected area
rapid displacements
detected in 2005
N. acquisitions
54
RSAT
Processed area
35
km
2Identified PS
2587
Mean PS density
74
PS/km
2Max PS density
1471
PS/km
2 -30 -20 -10 0 10 20 30 M a r-03 O ct -03 A p r-04 N o v -04 M a y -05 D e c -05 Ju l-06 Ja n -07 D isp la ce m e n t [ m m ] Time A1JZ8LOS
displ
acemen
t
[mm]
Time
4
thFebruary 2005
Test area: Naro (Italy)
PSI time-series analysis
-20 -15 -10 -5 0 5 10 15 20
M
ar
-03
Ju
l-03
N
o
v-03
M
ar
-04
Ju
l-04
N
o
v-04
M
ar
-05
Ju
l-05
N
o
v-05
L
O
S
d
is
p
la
c
e
m
e
n
t
[m
m
]
TimePS Code: A04YZ Vel: 0.0 mm/yr Coher: 0.94
-20 -15 -10 -5 0 5 10 15 20
M
ar
-03
Ju
l-03
N
o
v-03
M
ar
-04
Ju
l-04
N
o
v-04
M
ar
-05
Ju
l-05
N
o
v-05
L
O
S
d
is
p
la
c
e
m
e
n
t
[m
m
]
TimePS Code: A05SQ Vel: -11.6 mm/yr Coher: 0.93
-20 -15 -10 -5 0 5 10 15 20
M
ar
-03
Ju
l-03
N
o
v-03
M
ar
-04
Ju
l-04
N
o
v-04
M
ar
-05
Ju
l-05
N
o
v-05
L
O
S
d
is
p
la
c
e
m
e
n
t
[m
m
]
TimePS Code: A05NX Vel: -5.6 mm/yr Coher: 0.78
-20 -15 -10 -5 0 5 10 15 20
M
ar
-03
Ju
l-03
N
o
v-03
M
ar
-04
Ju
l-04
N
o
v-04
M
ar
-05
Ju
l-05
N
o
v-05
L
O
S
d
is
p
la
c
e
m
e
n
t
[m
m
]
TimePS Code: A05AB Vel: -4.6 mm/yr Coher: 0.79