by Falah Atta Fakhri Supervisors: Dr. Issaak Parcharidis

1. Long and short term monitoring of ground deformation in Thessaly basin using space-based SAR Interferometry Harokopio University of Athens Department of Geography PhD Candidacy Oral Examination by Falah Atta Fakhri Supervisors: Dr. Issaak Parcharidis Dr. George Mighiros Dr. Efthimis Karymbalis Tuesday, June 25, 2013

2. Agenda • Chapter One: Introduction • Chapter Two: Data acquisition and SAR interferometric techniques and processing • Chapter Three: Impact of groundwater on ground deformation. • Chapter Four: Impact of fault movement and earthquakes on ground deformation • Chapter Five: Impact of lithology types on ground deformation • Chapter Six: Impact of soil on ground deformation • Chapter Seven: The conclusions derived from this research study and Discussion.

3. Chapter One: Introduction PREFACE • Natural hazards comprise: • Hydro-meteorological hazards, which include floods and flash floods, droughts, wildfires, tropical cyclones and hurricanes, and severe storms. • Geological hazards, which include tectonic movement, earthquakes, tsunamis, volcanoes and explosive crater lakes, landslides, mudflows, erosion, and siltation. • Human-induced hazards comprise: • which include wars, groundwater and oil withdrawal, mining, and land degradation. • Together, all of these hazards contribute to serious environmental problems which in consequence affect and destroythe economic development of countries and finally, in turn, impact on all walks of life.

4. Study area • The study area is located in the eastern part of the northern Thessaly Plain in central of Greece.

5. Thessaly plain, indicating that the study area exists within the frames of ascending and descending radar image tracks

6. Study area problems and constraints The study area suffers from a ground deformation phenomenon which affects civil construction and agricultural activity. Furthermore it is a very complicated area due to the distribution of human hazards, which include groundwater withdrawal, and due to the presence of natural hazards for instance active tectonics.

7. SAR Interferometry This new geodetic technique calculates the interference pattern caused by the difference in phase between two images acquired by spaceborne SAR at two distinct times.

8. SAR InterferometricTechniques Repeated pass Interferometry (Conventional InSAR) In repeat-pass InSAR, two or more SAR images are acquired at different times with the same or a corresponding sensor from almost identical aspect angles. Interferometric Stacking The basic idea of interferogram stacking is to combine multiple observations into a single result. Persistent Scatterers Interferometry (PSI) This technique exploits temporal and spatial characteristics of interferometric signatures, collected from point targets.

9. Objectives of the Research Study 1- To evaluate the possibility of applying SAR interferometric techniques to monitor and map ground deformation in urban and agricultural lands over the long and short terms. 2- To investigate and identify the causes of ground deformation. 3- To evaluate the possibility of recognizing each individual cause of ground deformation by monitoring the time series behavior of ground deformation using the statistical results of SAR interferometric techniques.

10. 4- To apply spatial and qualitative correlations between ground deformation and parameters (precipitation, groundwater, fault movement, earthquake, lithology, and soil) to reveal the reality of ground deformation within the study area.

11. Flowchart of study research methodology Additional data collection SAR interferometry Geology Soil Hydrology and hydrogeology Meteorology Data acquisition Field- work Thematic maps Preprocessing Persistent scatterer interferometry Repeated pass interferometry Stacking interferometry Data management Development of geographic information system Production and interpretation of deformation maps Create spatial correlation Create statistical correlation Results

12. Chapter Two: Data acquisition and SAR interferometric techniques and processing Data and Methodology SAR Data Selection and Interferometric Processing (Ascending Track 143) • The total dataset consists of 24 Single Look Complex (SLC) SAR C-band images of ERS-1/2, during 1995–2000. Additionally, 15 SLC images of ENVISAT ASAR acquired during 2003–2008 by ESA, which cover the study area, have also been selected along this track.

13. Flowchart of preprocessing ASR images Processing raw data to obtain SLC format images Geometrical correction Add the parameters of orbits Multi-look Estimate perpendicular baselines of all the selected images crop image; Resample images by estimating initial range and azimuth offsets Corregister of SLC images Simulation SLC SAR images with the DEM , 90 (m) (SRTM)

14. Multi-look average image ascending track highlighting the study area and the mountains around the basin and urban area

15. Results and discussion Repeated pass interferometry processing Master image Slave image B┴ (m) Interval Days 19960228 19960403 -66.80 35

16. Coherence map for time interval 19960228_19960403ascending track LARISA

17. Differential interferogram for time interval 19960228–19960403 ascending track LARISA

18. Interferometric stacking processing Average coherence for time interval 1995–2008 ascending track highlighting the coherence of the reference point inside the red circle LARISA

19. Ground deformation rates along LOS direction deduced by interferometric stacking, for the considered time intervals (1995–2008) Ascending track and different acquisition. Background is an average of multi-look SAR intensities. The selected reference point is marked with a green Bp is 0-200 m, 29 interferograms LARISA

20. Persistent (Permanent) Scatterers Interferometric (PSI) Distribution of geo-coded radar targets (persistent scatterers) in Larissa basin before expansion. The average in line of sight (LOS) velocity for the period (1995–2006)number of points are 1866 LARISA

21. Distribution of geo-coded radar targets (persistent scatterers) in Larissa basin after expansion. The average in line of sight (LOS) velocity for the period (1995–2006) number of points are 62551 LARISA

22. SAR Data Selection and Interferometric Processing (Descending Track 279) The total dataset consists of 48 SLC SAR C-band images of ERS-1/2 from 1992 –2000 and additionally, 25 SLC images of ENVISAT ASAR from 2002 – 2010 acquired by ESA,, which cover the study area have been selected along this track

23. Repeated pass interferometry processing Master image Slave image B┴ (m) Days 19980802 19980906 - 1.51 35

24. Coherence map for time interval 19980802–19980906 descending track LARISA

25. Differential interferogram for time interval 19980802–19980906 descending track LARISA

26. Interferometric stacking processing Coherence map for time interval 1992–2010 descending track highlighting the coherence of reference point inside the red circle LARISA

27. Ground deformation rates along LOS direction deduced by interferometric stacking, for the considered time intervals (1992-2010), Bp 0-150, 73 inteferograms LARISA

28. Persistent (Permanent) Scatterers Interferometry (PSI) Distribution of geo-coded radar targets (persistent scatterers) in Larissa basin before expansion. The average in line of sight (LOS) velocity for the period (1992–2010)number of points are 1930 LARISA

29. Distribution of geo-coded radar targets (persistent scatterers) in Larissa basin after expansion. The average in line of sight (LOS) velocity for the period (1992–2010)number of points are 4801 LARISA

30. Chapter Three: Impact of groundwater on ground deformation Location of groundwater monitoring network within study area, superimposed on SLC SAR image

31. Three point candidates of the PSI with different distances from borehole AD6 ASCENDING TRACK 1995 - 2006

32. LOS Displacemnt of point candidates of PSI corresponding to monthly precipitation amount. Displacement time series of point candidates are rescaled to the first acquisition (i.e. 28 June 1995). ASCENDING TRACK 1995 - 2006

33. LOS Displacemnt of point candidates corresponding to the groundwater level of borehole AD6. Displacement time series of point candidates are rescaled to the first acquisition (i.e. 28 June 1995).ASCENDING TRACK 1995 - 2006

34. Conventional SAR Interferometry Seasonal Deformation19960228–19960403ASCENDING TRACK

35. Conventional SAR Interferometry Seasonal Deformation19980802–19980906 DESCENDING TRACK 279

36. Impact and interference type of clay minerals with fluctuation of groundwater level on land deformation Rainfall Groundwater withdrawal Rising groundwater level Decline of groundwater level Presence of clay minerals which have the capability to swell and shrink Water enters between clay layers Water leaves from among mineral layers Activation of swelling operation Activation of shrinking operation Subsidence of the ground Uplift of the ground Compression of materials Maybe are caused microseismic (3–4) magnitude?

37. Chapter Four: Impact of faults movement and earthquakes on ground eformation • In order to examine and investigate the correlation between fault movements and ground deformation by implementing three techniques, conventional SAR interferometric, interferometric stacking and persistent scatterers interferometry (PSI), • Fault traces which are distributed within the study area of the eastern part of northern Thessaly were digitized from the papers by (Caputo, 1993), (Caputo and Pavlides, 1993), (Caputo et al., 1994), (Caputo et al., 2004), (Caputo and Helly, 2005) and (Caputo et al., 2006). • Thereafter these were corrected and rectified depending on 7 geological maps of Thessaly at a scale of 1:50,000 issued by the Greek Institute of Geology and Mineral Exploration, which were used along with field observations. • In addition, by using a seismotectonic map of Greece with seismogeological data at a scale of 1:500,000, a shape file was consequently created and identified utilizing GIS software ArcGIS 9.3.

38. Earthquake events data within the study area were collected by utilizing the earthquake catalogue of the (Institute of Geodynamics), National Observatory of Athens, • An attribute table was then created from this catalogue. • Consequently, a shape file of earthquake events was created utilizing Arc GIS 9.3 for the period 1964 – 2010 with magnitude M >= 3 and depth varying between 0 – 30 km.

39. Distribution of faults and earthquakes within study area

40. The interference effects of fault movement on ground deformation will be discussed and interpreted in a probability approach depending on spatial correlation, for the reason that no statistical correlation or model-building has been done between ground deformation and fault movement.

41. Ascending track 143 Interferometric stacking

42. Total deformation at Larissa estimated with interferometric stacking technique, June 1995-March 2008

43. Descending track 279Interferometric stacking

44. Total deformation at Larissa estimated with interferometric stacking technique, November 1992 – October 2010

45. ASCENDING TRACK 1995 – 2006Persistant Scatterers Interferometric (PSI)

46. Frequency of deformation rate of points targets at LARISA 1995-2006

47. Frequency of deformation rate of points targets at Tyrnavos 1995-2006

49. Location of selected candidate points minimum and maximum deformation rate, ascending track 143, settlement of Larissa

50. Conventional SAR Interferometry ASCENDIGN TRACK SEASNAL DEFORMATION19960228_19960403