Integration between spaceand ground-based data sets: application on ground deformations measurements

Integration between

space-and ground-based data sets:

application on ground deformations

measurements

Giuseppe Puglisi

Istituto Nazionale di Geofisica e Vulcanologia

Sezione di Catania – Osservatorio Etneo

This work has been carried out in cooperation with:

F. Guglielmino (INGV, Sezione di Catania – Osservatorio Etneo) G. Nunnari (Dip. IEES; Univ. di Catania)

Outline

>

Rationale

>

Methodology

>

Synthetic test

>

Applications: Test Cases

•

Etna

–

volcanic sources

–

earthquakes

•

L’Aquila: earthquake

GEO 2012-2015 WORK PLAN

>

Task DI-01: Informing Risk Management and Disaster

Reduction

•

Component C2: Geohazards Monitoring, Alert, and Risk Assessment.

–

Priority Actions

….

Apply a fully integrated approach to geohazards monitoring, based on

collaboration among existing networks and international initiatives, using

new instrumentation such as in-situ sensors, and

aggregating space

(radar, optical imagery) and ground-based (subsurface) observations

.

Develop open comprehensive natural-hazards datasets, initially focusing on

selected targets (e.g. Supersites)

Integration between Space- and

Ground-based deformation measurements

Geodetic Techniques

(GPS, levelling, tilt)

Time

Space

Low temporal resolution

From Low to High

temporal resolution

Point-wise measurements

Spatial distributed

Type

From 1D to 3D

1D (LOS)

DInSAR

Goal:

To take advantage of their complementary nature to obtain:

- a continuous 3D deformation map

- the complete strain tensor information

Guglielmino, Nunnari, Puglisi, Spata (2011).

GPS data DInSAR Data

Modified Weighted Least Squares

3D Deform. & Strain

Samsonov, Tiampo et al. (2006)

GPS data Kriging Interpolation DInSAR Data Analytical Optimization 3D Deform. No strain Gudmundsson et al. (2002) GPS data Kriging Interpolation DInSAR Data

Random Markow Field Theory Simulated Annealing Optimization

3D Deform. No strain

SISTEM

Small Deformation Theory

Let x

_o

(x

₁₀

, x

₂₀

, x

₃₀

)

the position of an arbitrary point P

surrounded by N

points whose position

and displacements are respectively x

_(n)

=(x

_1(n)

, x

_2(n)

, x

_3(n)

)

and u

_(n)

=(u

_1(n)

,u

_2(n)

, u

_3(n)

)

.

In a linear approach the small motions around a point P

can be modelled by the N

equations:

)

3

..

1

,

(

) ( ) (

=

H

∆

x

+

U

i

j

=

u

_{i n ij j n i}           = ⊗ + = = 33 23 13 23 22 12 13 12 11 ) ( 2 1

ε

ε

ε

ε

ε

ε

ε

ε

ε

ε

ij Hij Hji ei ej E

Strain tensor

          − − − = ⊗ − = = Ω 0 0 0 ) ( 2 1 1 2 1 3 2 3

ω

ω

ω

ω

ω

ω

ω

_ij H_ij H _ji e_i e_j

Rigid body rotation tensor

ij ij j i i j ij

E

u

u

H

=

+

Ω

∂

∂

=

Displacement gradient

0 ) ( ) (n j n j j

x

x

x

=

−

∆

Relative position

We assume the Small Deformation Theory, as the mathematical model, and use of the WLS

algorithm for searching the parameters of the model

. It allows:

- To simultaneously define the whole set of parameters

- To estimate the internal accuracy of parameters (Variance-Covariance Matrix)

- To estimate the whole information about the strain (Strain & Rigid Body Rotation Tensors)

The synthetic test

Pressure point source (Mogi source)

Topography of a synthetic volcano

2 / 3 2 2 3 ) ( 4 3 d f d P a x + = ∆ µ 2 2 3/2 3 ) ( 4 3 d f f P a z + = ∆ µ Experimental conditions µ=30 GPa ; d=5000m ; a3_P=1017_Pa*m3

Volcano & pressure source

(

)

(

(

x y

)

w

)

e

z

y

x

z

,

=

₀ − 2+ 2 /

Synthetic deformations

maps and

Experimental Points (EP)

Integrated

displacements

components

(SISTEM)

Residuals

(l), (m), (n): normalized histograms of the corresponding residuals

errors, the mean value and standard deviation.

50 100 150 200 250 300 350 400 50 100 150 200 250 300 350 400 450

East

North

Up

DInSAR

Errors as a function of the number of EP (Experimental Points)

• The accuracy decrease, as the

number of GPS points increase

(negligible when EP > 50-70)

• Vertical accuracy is better than

the Horizontal accuracy.

Dilatation

differential rotation magnitude

maximum shear strain

Test Case: Mt. Etna

Monday, 16 September 2013

Etna 2008-2009 eruption

GPS data

DInSAR Data

SISTEM

3D Surface

Motion Map

Type of Geohazard: eruption

Source of deformations: magmatic intrusion (dyke)

Date of the event: 13 May 2008

Data set: - ~ 60 GPS benchmarks and permanent stations

- 1 DInSAR deformation map (ENVISAT)

- from June 2007 to May 2008

+

Results of the integration

North

East

Up

d

is

p

la

c

e

m

e

n

ts

(

c

m

)

E

rr

o

rs

(

c

m

)

Results of the Integration

Maximum shear

Volumetric Dilatation

… but SISTEM allows investigating also the strain tensor; two invariants:

These results, which provide both accurate and fine spatial characterization of ground deformation, are hence promising for future studies aimed at improving the knowledge of the dynamic of the Mt. Etna .

Test Case: L’Aquila Earthquake

Monday, 16 September 2013

L’Aquila Earthquake

GPS data

SISTEM

3D Surface

Motion Map

Type of Geohazard: earthquake

Source of deformations: fault/s

Date of the event: 6 April 2009

Data set: - 75 GPS benchmarks and permanent stations

- 3 DInSAR deformation maps (ENVISAT, ALOS)

- from April 2008 to May 2009

+

=

ENVISAT Descending Interferogram

ENVISAT Ascending Interferogram

ALOS Ascending Interferogram

+

+

Results of the integration

F. D i P_ag an_ica F. D i B az za_n o _{F. D} i M_o n t.-F o_s sa F. R_o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P_ag an_ica F. D i B az za_n o _{F. D} i M_o n t.-F o_s sa F. R_o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P_ag an_ica F. D i B az za_n o _{F. D} i M_o n t.-F o_s sa F. R_o io_-C a_n et_ra F. C olle P_ratic ciolo

F. del Pettino

3D displacement

components.

max lowering 250 mm

F. D i P ag an_ica F. D i B az za_n o _{F. D} i M o_n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P ag an_ica F. D i B az za_n o _{F. D} i M o_n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P ag an_ica F. D i B az za_n o _{F. D} i M o_n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo

F. del Pettino

Associated standard error.

Horizontal error < 15 mm

Vertical error < 2.5 mm.

F. D i P ag_an ica F. D i B az za_n o _{F. D} i M_o n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P ag_an ica F. D i B az za_n o _{F. D} i M_o n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino F. D i P ag_an ica F. D i B az za_n o _{F. D} i M_o n t.-F_o s sa F. R o io_-C a_n et_ra F. C olle P_ratic ciolo F. del Pettino

3D strain invariants.

SISTEM results

3D components analysis

F. D i P ag an ica F. D i B az za_n o _{F. D} i M o n t.-_F o_s sa F. R o io -C a_n et_ra F. C olle P ratic_ciolo F. del Pettino F. D i P ag an ica F. D i B az za_n o _{F. D} i M o n t.-_F o_s sa F. R o io -C a_n et_ra F. C olle P ratic_ciolo F. del Pettino F. D i P ag an ica F. D i B az za_n o _{F. D} i M o n t.-_F o_s sa F. R o io -C a_n et_ra F. C olle P ratic_ciolo F. del Pettino -300 -250 -200 -150 -100 -50 0 50 100 150 200 62 112 162 212 262 est nord up PAGANICA FAULT MONTICCHIO-FOSSA FAULT ROIO CANETRA FAULT

MT. OCRE FAULT _{The cross section show a complex}

kinematics whit a main displacements of of the Paganica fault, and involvement of several structure.

On the north-east area is evident an increase of the northward motion

F. D i P ag an ica F. D i B az zan o F. D i M o n t.-F os sa F. R o io -C an etra F. C olle P raticciolo F. del Pettino F. D i P ag an ica F. D i B az zan o F. D i M o n t.-F os sa F. R o io -C an etra F. C olle P raticciolo F. del Pettino F. D i P ag an ica F. D i B az zan o F. D i M o n t.-F os sa F. R o io -C an etra F. C olle P raticciolo F. del Pettino

SISTEM results

3D strain analysis

-100 -50 0 50 100 150 200 250 300 350 400 450 62 112 162 212 262 Dilatation Diff_rotation Max Shear PAGANICA FAULT MONTICCHIO-FOSSA FAULT ROIO CANETRA FAULT MT. OCRE FAULT

The 3D strain analysis evidence a

strong dilatation between the

Paganica and Roio Canetra Fault

associated whit a Max Shear Strain

located along the Monticchio-Fossa

fault.

It is noteworthy a compression

corresponding to the Paganica fault

trace.

Test Case: Etna Earthquake

Etna Earthquake

GPS data

SISTEM

3D Surface

Motion Map

Type of Geohazard: earthquake

Source of deformations: fault/s

Date of the event: 3 April 2010

Data set: 35 GPS benchmarks and permanent stations

- 4 DInSAR deformation maps (ENVISAT, ALOS)

- 1 levelling line (20 benchmarks)

- from October 2009 to May 2010

+

=

2 ALOS Ascending Interferograms

ENVISAT Descending Interferogram

ENVISAT Ascending Interferogram

+

+

Levelling data

DInSAR Satellite Data

ENVISAT data

We analyzed :

the ascending pair related to 07/10/2009 – 05/05/2010 and the descending pair related to 18/11/2009 – 07/04/2010 time interval

The ENVISAT images show the general seaward movement of the eastern flank of Mt. Etna well. They also show very intense but local LOS

displacements on the ENVISAT ascending interferogram and a lower variation for the

descending geometry

The differences in the LOS displacements between ascending and descending geometry, are probably due to the oblique normal/left-lateral kinematics of the PFS (as deduced also by GPS and leveling data

Indeed, both vertical (lowering) and horizontal (eastwards) components of motion on the southern side of the fault, produce a strong lengthening of the LOS distance for ascending geometry, while the two components act in opposite ways for the descending geometry, resulting in lower LOS distance variations compared to the ascending data set

DInSAR Satellite Data

ALOS data

We analyzed two frames covering two adjacent tracks (track 637 and 638), both along ascending path, referring to 21/02/2010-08/04/2010 (track 637) and 22/03/2010-07/05/2010 (track 638). It is worth noting that the deformation patterns, are the same for the two tracks.

In particular, a deformation of about 23 cm in the LOS of PALSAR has been measured.

The ALOS images confirmed a strong ground deformation in the near field of the fault, rapidly decreasing on moving away from it. This pattern is not imaged by ENVISAT ascending data because it exceeds the ASAR maximum detectable deformation gradient for C-band frequency, which is 1.4 cm per pixel.

LOS deformation of about 23 cm, detected by ALOS, is due mainly to the horizontal component because the maximum vertical displacement measured by leveling data is only of 7cm.

Comparison Levelling & LOS ENVISAT

In order to compare the SAR data with the in situ measurements, we extracted LOS displacements of those pixels closest to the leveling benchmarks; in Figure the vertical displacements measured by leveling are plotted together with the ascending LOS displacements of their nearest pixels. The plot shows a very good agreement between the two datasets, and as expected the magnitude of the LOS displacements is higher due to the contribution of the eastward motion of the southern side of the fault. Finally, both leveling and DInSAR data confirm that an intense local deformation episode occurred very close to the PFS, affecting a narrow strip ( 500 m) along the southern side of the fault.

SISTEM Results

The 3D components

analysis shows a maximum eastward movement (370 mm) associated with maximum relative vertical displacements (70 mm) in a narrow area along the PFS. The cross sections indicate the strong displacements occurring very close to the PFS and, on its southern side, the widespread ESE-ward motion of the eastern flank of Mt. Etna.

Furthermore, the three cross sections highlight the

opposite movement of the fault hanging wall (generally trending south) with respect to the footwall, due to the “elastic rebound” of the PFS involved by earthquakes.

Conclusive remarks - 1

Geodetic and DInSAR integration based on small deformation theory

The SISTEM method was applied effectively on areas where the geodetic

networks (GPS, leveling) well cover the area and frequent SAR passes are

available.

•

Geodetic and DInSAR data are simultaneous integrated

without the preliminary step of the Kriging interpolation

• Deformation field and relevant standard errors

• Strain tensor and relevant standard errors

• Rigid body rotation tensor and relevant standard errors

Conclusive remarks - 2

• To include different kind of geodetic data, such as EDM, Tilt

• To apply the algorithm to the time series (both GPS and

DInSAR)

• To use the SISTEM to optimize the configuration of the

ground-based networks and/or for the tasking of future EO

missions

• To optimize the algorithm for a semi-automatic processing

(from supervised to nearly-unsupervised processing)

References

Bonforte A., Guglielmino F. and Puglisi G., Interaction between magma intrusion and flank dynamics at Mt.

Etna in 2008, imaged by integrated dense GPS and DInSAR data. Bull. Volcanol., in print.

Guglielmino F., Anzidei M., Briole P., Elias P. and Puglisi G. (2012). 3D displacement maps of the 2009

L’Aquila earthquake (Italy) by applying the SISTEM method to GPS and DInSAR data. Terra

Nova, Vol 00, No. 0, 1–7. doi: 10.1111/ter.12008.

Guglielmino F., Bignami C., Bonforte A., Briole P., Obrizzo F., Puglisi G., Stramondo S. and Wegmuller U. (2011). Analysis of satellite and in situ ground deformation data integrated by the SISTEM

approach: The 3 April 2010 earthquake along the Pernicana fault (Mt. Etna - Italy) case study.

Earth Planet. Sci. Lett., 312, 327–336.

Guglielmino F., Nunnari G., Puglisi G. and Spata A. (2011). Simultaneous and integrated strain tensor estimation from geodetic and satellite deformation measurements to obtain three-dimensional

displacement maps. IEEE Trans. Geosci. Remote Sens., 49, 1815–1826.