1 SPACE BORNE RADAR INTERFEROMETRIC MAPPING OF PRECURSORY DEFORMATIONS OF A DYKE COLLAPSE, DEAD SEA, JORDAN Closson, Abou Karaki, al-Fugha

2 The case study : the collapse of the salt evaporation pond 19 of the Arab poatsh Company 1650m Ikonos :

3 The SEP costed 32 M Jordan Dinar It collapsed on March 22, M m3 brine to the Dead Sea in less than one our

4 After the mid sixties The Dead Sea Decrease from -392m To -418m

5 ERS Radar Images Lisan Coastline May, June,

6 SAR-based remote sensing technique

7 Remote sensing SAR SAR = Synthetic Aperture RADAR (RAdio Detection And Ranging) SAR is a sensor able to generate high resolution images imaging sensor:  Allows the observation of the Earth surface in 2D exemple of another sensor : Radar altimetre: provide data in one dimension. Allow generation of topographic maps

8 main characteristics of SAR images: 1. It is an active system (illuminate the area of interest with microwaves)   independant of solar illumination  allows measurement in day and night conditions 2. use micro-waves to penetrate through cloud cover   allows observations in cloud cover areas remark: it alters the accuracy of measurements 3. Its a coherent system by opposition to visible remote sensing wich use the incoherent light of the sun  allows the use of interferometry technic SAR remote sensing - properties

9 4. SAR allows the observation of Earth surface properties that are not accessible to visible sensors - rugosity, dielectric properties (through coherence images) - possibilities to penetrate - the vegetation (L band) - ultra dry soil - snow cap 5. The Sar resolution is independant of the distance between the sensor and the objective 6. – Allows the utilisation of different polarization in transmission as well as in reception : HH, HV, VV, VH - Allows the utilization of different frequencies SAR remote sensing - properties

10 SAR applications 1. Geometric applications, based on the interferometric phase: - Generation of digital terrain model (DTM)  Technic: SAR interferometry (InSAR) - Control the deformations fields over the Earth surface  Technic : differential SAR interferometry (DInSAR) 2. Thematic application - Change detection from coherence variation through time (soil erosion, flood)

11 Deformation fields : principle S P P’ M

12 DInSAR The differential interferometric phase is a sum of several components  Topo topographic phase  Mov movement  Atm atmosphere  Noise noise of instruments

13

14

15 Subidence from

16

17

18

19