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12/01/12 04:26 AM [email protected]

Geological Applications and Mineral Resources Division (GAMRD)

Ashraf Mohamed RatebResearcher Assistant (Geophysist)

National Authority for Remote Sensing and Space Sciences (NARSS)[email protected]



1.0.Infusion of Space TechnologyIn Solid Earth Geophysics



A possible vision of Space Technology Future fusions in Solid Earth Science



2.0. SAR Interferometry

Interferogram of Chile earthquake 2010

Massonnet et al. (1993)

Interferogram of landers earthquake 1992



3.1.SAR = Synthetic Aperture RADAR (Radio Detection And Ranging). SAR is a sensor able to generate high resolution images

Allows the observation of the Earth surface in 2D

It is an active system (illuminate the area of interest with microwaves) independant of solar illumination

Allows measurement in day and night.

High penetration of Cloud cover

Extensive geogpraphic coverag

Rapid detailed accurately georeferenced and mapping of large zones

3.2.Main characteristics of SAR images



S

P

P’

M

MΦ

SΦ

Figure 1.3SAR Interferometry principles

3.3. Theory

The differential interferometric phase is a sum of several components

NoiseAtmMovTopoInt Φ+Φ+Φ+Φ=∆Φ

ΦTopo topographic phaseΦMov movementΦAtm atmosphereΦNoise noise of instruments



3.4.Satellite InSAR ~ Conditions for Measuring Motion ~

To measure motion, the following must apply:• The time delay must be appropriate to the scale of motion to be measured (i.e., the motion must obey the Nyquist sampling theorem), and

• The motion must have enough spatial cohesiveness that the coherence is high enough.

• Plus one of the three conditions needed to remove the topographic component of the phase:

• The baseline must be small enough that the topography component can be neglected.

• An accurate DEM must be used to remove the topographic component, orThree passes must be used to remove the topographic component



3.5.History of SAR Sensors



4.1.InSAR techniques4.1.2-Differential InSAR (DifSAR):-

Differential InSAR (DifSAR) maps subtle topographic change (surface motion) that has occurred during the period spanned by two satellite Synthetic Aperture Radar (SAR) data acquisitions.

Key features:•Continuous field of motion across coherent areas•Detect moton ranging from centimetres-to-metres•Centimetric accuracy•Map and monitor large areas (1000s of km2)•Map historical events using archive SAR data (as far back as 1992)•Monitor sites at regular intervals by programming new SAR data acquisitionsDifSAR is widely applied within the following markets sectors: Oil & gas, mining, buildings & infrastructure, water & environment, sustinable energy and geohazards & risk.

Oilfield Compaction



4.1.2.-Persistant Scatterer InSAR (PSI)Persistent Scatterer Interferometry (PSI) is an advanced differential interferometric technique which involves the processing large volumes of multi-temporal Synthetic Aperture Radar (SAR) data to identify networks of persistently reflecting surface feature (e.g. buildings, bridges, infrastructure and rocky outcrops), against which precise (millimetric) measurements of motion can be made.Fugro NPA's PSI processing and products have been validated and certified by the European Space Agency.

Key features:100s to 1000s of Persistent Scatterer (PS) measurement points per km2A 'virtual GPS' network with individual PS motion time seriesMap subtle change; detect motion rates of millimetres to decimetres per yearMillimetric accuracyMap and monitor specific sites and large areas (1000s of km2)Map historical events using archive SAR data (as far back as 1992)Monitor sites at regular intervals by programming new SAR data acquisitionsPSI is widely applied within the following markets sectors: Oil & gas, mining, buildings & infrastructure, water & environment, sustinable energy, utilities and geohazards & risk.

Flood Risk



4.1.3-Corner Reflector InSAR (CRInSAR)Networks of Corner Reflectors (CRs) are deployed in regions of low natural radar response (e.g. rural environments) and across specific features (e.g. landslides, dams, embankments, underground water reservoirs), to provide a persistent response to incoming radar signals from overpassing Synthetic Aperture Radar (SAR) satellites.Key features:•Point specific motion measurement network•Detect motion ranging from millimetres to decimetres•Map and monitor specific structures or areas characterised by low natural radar response•Supplement and/or expand existing Persistent Scatterer (PS) networks

Corner Reflector



Assuming a supply of data, the ideal strategy might be as follows: Continuous acquisition of data over the area at every opportunity to enable PSInSAR as soon as possible. Installation of CRs around sensitive developments or faults. Measurements against these can be made after only two post installation acquisitions. The acquisition strategy allows for the generation of a conventional interferogram should an earthquake of large magnitude strike.

If we assume an existing 30-scene + archive of SAR data, and a promised continuity of repeat acquisitions, then the InSAR technique to apply is determined by a) area to be monitored,b) ground velocity, andc) distribution of existing scatterers. Consider the table below.



5.0.Software'sAn interferogram can be computed with both free InSAR software packages and A commercial packSages.

5.1.Commercial packages include:1) DIAPASON originally developed by the French Space Agency (CNES), now

maintained by Altamira Information for both UNIX and Windows platforms (http://www.altamira- information.com/html/index.php);

2. GAMMA SAR developed by Gamma Remote Sensing for Solaris, Linux, OSX, and Windows platforms http://www.gamma-rs.ch/

3) IMAGINE InSAR Embedded in ERDAS IMAGINE remote sensing software suite developed by Leica

Geosystems Geospatial Imaging (http://gi.leica-geosystems.com/default.aspx); 4) Pulsar, developed by Phoenix Systems for UNIX based platforms (http://

www.phoenixsystems.co.uk/);

5) SARscape, that was developed by sarmap s.a.; a Swiss company (http://www.sarmap.ch/). SARscape is interfaced with ENVI and can be run on Windows or Linux based personal computers.



7) SOCET GXP®Company: BAE Systems

Software for geospatial analysis and photogrammetryAutomatic measurement and storage of properties such as scale, elevation, latitude and longitude in a series of images in order to expedite geospatial production, image analysis, and map creation Data then can be used to perform before-and-after site comparisons, coordinate operational missions, assess navigation safety and monitor changes over timePowerful functionality for triangulation, DEM extraction, orthorectification and feature collection

: 8) PCI Geomatics

6) DELTA SARStand-alone software tool that automatically generates coherent change detection

(CCD) imagery and amplitude change detection imagery (ACD) Runs on a wide range of computer configurations including LINUX, Windows (XP and Vista) as well as Macintosh OSX, 64-bit operating systems are not required, but are highly recommended; Perl and Java Runtime Environment (JRE) 1.5+ must be installed

http://www.gamma-rs.ch/



10) IMAGINE Radar Mapping Suite Company: GEOSYSTEMS GmbH

Extensive set of radar mapping tools including advanced interferometric SAR processing techniquesSoftware modules support transformation of source data into orthos, terrain, features, maps, 3D data, land cover data and processing models Fully integrated into ERDAS IMAGINE 2010, supports TerraSAR-X data formats & products: SSC, MGD, GEC and EEC products for High-resolution SpotLight, SpotLight, StripMap and ScanSAR acquisition modes Developed in co-operation between ERDAS and the German Aerospace Centre (DLR) and GEOSYSTEMS

9) Definiens DeveloperCompany: Definiens AG

Definiens Developer is a completely integrated environment designed for image analysis specialists to develop, test and package new image analysis applications Can be used as a standalone tool or in combination with the Definiens eCognition® Server to provide a processing environment for the batch execution of image analysis using a high-performance grid computing Environment Solutions created in Definiens Developer can also be packaged within Definiens Architect, a simple end user tool enabling users to calibrate and run image analysis applications

http://www.baesystems.com/



2) The Repeat Orbit Interferometry Package (ROI_PAC) developed at the Jet Propulsion Laboratory and the California Institute of Technology (JPL/Caltech), available at: http://www.openchannelfoundation.com/ projects/ROI_PAC/index.html;

3) Doris (Delft object-oriented radar interferometric software) developed by the Delft Institute of Earth Observation and Space Systems of Delft University of Technology downloadable from http://enterprise.lr.tudelft.nl/doris/;

4) Interferometric Processing System (IPS) developed by the Alaska Satellite Facility (ASF). http://www.asf.alaska.edu/~rgens/software/interferometric_processing_system.html

Free Software's1) RAT (Radar Tools)Open-source software tool for advanced processing of SAR remote sensing dataOriginally started as a student’s project and currently under further development at the Department of Computer Vision and Remote Sensing of the Technical University of Berlin Programmed in IDL (Interactive Data Language) and uses IDL widgets as graphical user interfaceb Current features include speckle filters, polarimetric basis transforms and decompositions, as well as an interferometric processing chain

5.2.Free Software's



6.0 SAR Processing

Figure (3.5. )Flow chart of InSAR Processing .



• Crop classification• Forestry• Oceanography• Sea ice• De-mining• Cartography• Topography• Geology• Hydrology• Meteorology• Water equivalent ice thickness• Snow monitoring• Tree species• Vegetation heights• Vegetation biomass• Soil moisture• Surface slopes• Surface roughness

7.0.Applications



Interferograms

volcanoes.usgs.gov/About/What/Monitor/Deformation/Westdahl.html

Observed interferogram

1993 - 1998

Modelled interferogram

For 0.5 km3 magma intrusion

Westdahl Peak Volcano, Alaska



Figure 1: Major seismic zones of Egypt (Abou Elenean 1997).

Figure 2.5 Spatial distributions of earthquakes epicenters in the Gulf of Aqaba (1970-2003) (USGS, NRIAG AND

IGI Catalogs) (Rateb.M.A., 2010)



Figure 2.6 A. The frequency of the recorded earthquake events through the time period 1970-2009.note the swarms of 1983, 1990, 1993, 1995,2003 and 2008. (USGS, NRIAG AND IGI Catalogs) (Rateb.M.A., 2010)

Figure 2.1 General map of the study area (1)Landsat TM of the study area (2) bathematery of the Gulf of Aqaba with main active faults (3) Location of 1995 main shock



Figure 5.1. Co-seismic interferogram of frame 585 for the period 29/03/95–29/11/95. Each fringe cycle corresponds to 26.8mm satellite-to-ground line of sight displacement (Rateb.M.A., 2010)

A

B

Figure 5.3. The displacement map of the co-seismic period (-8 months + 1 week) (Rateb.M.A., 2010)

Conventional InSAR (Rateb.M.A., 2010)



29/11/95-03/04/97

B

Figure 5.6. Post-seismic interferograms (B) for the period (29/11/95-03/14/97) (Rateb.M.A., 2010)

Figure 5.7. Post-seismic interferograms for the period

(29/11/95-29/01/2000). (Rateb.M.A., 2010)



Figure 3.6. Mean LOS surface displacement in the 1993-2000 period, superimposed on the average amplitude image of greater Cairo (After .,2006)

PSI Technique( Aly., 2006)



Fig. 4: Comparison of common subsidence areas for ERS, ENVISAT and ALOS studies. Red polygons delimit the affected zones. Only the area marked as “B” presents a subsidence behavior in ERS and ENVISAT maps, but it is stable in ALOS study

CR technique (Altamire ., 2010)



Fig. 83: ENVISAT InSAR result showing the ground subsidence and soil uplift in urban and rural area of Alexandria (Egypt) (Altamira Production, 2010)



ThanksQ&A

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