ACTAUNIVERSITATISUPSALIENSISUPPSALA2007

Digital Comprehensive Summaries of Uppsala Dissertationsfrom the Faculty of Science and Technology 318

Ground Movements in the ZagrosFold-Thrust Belt of SW IranMeasured by GPS and InSARCompared to Physical Models

FARAMARZ NILFOUROUSHAN

ISSN 1651-6214ISBN 978-91-554-6918-4urn:nbn:se:uu:diva-7928

Dissertation at Uppsala University to be publicly examined in Axel Hambergsalen,Geocentrum, Villavägen 16, SE-752 36 Uppsala, Friday, June 1, 2007 at 10:00 for the Degreeof Doctor of Philosophy. The examination will be conducted in English.

AbstractNilfouroushan, F. 2007. Ground Movements in the Zagros Fold-Thrust Belt of SW IranMeasured by GPS and InSAR Compared to Physical Models. Acta Universitatis Upsaliensis.Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science andTechnology 318. 38 pp. Uppsala. ISBN 978-91-554-6918-4

This thesis uses geodetic satellite data to measure present-day crustal deformation in the Zagrosfold-thrust belt (SW Iran). Geodetic-type measurements are also used in down-scaled modelsthat simulate the surface deformations seen in convergent settings like the Zagros fold-thrustbelt.

Global Positioning System (GPS) measurements of three surveys between 1998 and 2001indicate 9 ± 3 mm/yr and 5 ± 3 mm/yr shortening across the SE and NW Zagros, respectively.GPS results show that in addition to the different rates and directions of shortening on eitherside of the NS trending Kazerun fault, local along-belt extension occurs to the east.

Differential SAR interferograms of ERS1 & 2 images between 1992 and 1999 detect 8 ± 4mm/yr uplift rate across a newly recognized fault in SW Qeshm Island. This can be attributedto a steep imbricate thrust that may still represent the local Zagros deformation front.

The salt diapirs in the Zagros rise from a source layer that acts as a low-frictional decollementthat decouples the deformation of the cover sediments from their basement in the eastern Zagroswhereas the cover to the west deforms above a high-friction decollement. Physical models wereprepared to simulate cover deformation in the Zagros by shortening a sand pack above adjacenthigh- and low-frictional decollements (represented by a ductile layer). The strain distributionsdiffered above the two types of decollements; it was more heterogeneous above the salt wherelocal extension in the shortening direction was dominant. A separate work also investigatedsystematically the role of basal friction on cover deformation in convergent settings. Accurateheight measurements of the model surface by laser-scanner indicated a deformation front moredistal than usual, particularly in the low-basal frictional models. The volume reduction in ourshortened sand models correlated directly with their basal friction.

Keywords: Zagros fold-thrust belt, deformation, GPS, InSAR, physical modeling, tectonics,convergent settings, basal friction

Faramarz Nilfouroushan, Department of Earth Sciences, Uppsala University, Villavägen 16,SE-752 36 Uppsala, Sweden

c© Faramarz Nilfouroushan 2007

ISSN 1651-6214ISBN 978-91-554-6918-4

urn:nbn:se:uu:diva-7928 (http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7928)

”We are like dwarfs on the shoulders of giants, so that we can see

more than they, and things at a greater distance, not by virtue of

any sharpness of sight on our part, or any physical distinction, but

because we are carried high and raised up by their giant size.”

Bernard of Chartres, 1125

Dedicated to:

My beloved wife and son (Tabsom and Shayan),our families and my teachers

List of Papers

This thesis is based on the following papers, which are referred to in the textby their Roman numerals.

I Khaled Hessami, Faramarz Nilforoushan, Christopher J. Talbot,2006, Active deformation within the Zagros Mountains deducedfrom GPS measurements, Journal of the Geological Society, Lon-don, 163, 143-148.

II Faramarz Nilforoushan, Hemin Koyi, 2007, Displacementfields and finite strains in a sandbox model simulating afold-thrust belt, Geophysical Journal International, doi:10.1111/j.1365-246X.2007.03341.x.

III Faramarz Nilforoushan, Hemin A. Koyi, Jan O. H. Swantesson,Christopher J. Talbot, 2007, Effect of basal friction on surfaceand volumetric strain in models of convergent settings measuredby laser scanner, Journal of Structural Geology, submitted.

IV Faramarz Nilforoushan, Christopher J. Talbot, 2007, SAR inter-ferometry locates and constrains the kinematics of an active faultalong SW Qeshm Island, offshore Zagros, manuscript.

Additional publications (during my stay at Uppsala) which are not includedin this thesis are:

• Nilforoushan F., Masson F., Vernant P., Vigny C., Martinod J., Abbassi M.,Nankali H., Hatzfeld D., Bayer R., Tavakoli F., Ashtiani A., DoerflingerE., Daignieres M., Collard P., Chery J., 2003, GPS network monitors theArabia-Eurasia collision deformation in Iran, Journal of Geodesy, 77, 411-422.

• Vernant P., Nilforoushan F., Chery J. ,Bayer R. , Djamour Y., Masson F.,Nankali H., Ritz J.F., Sedighi M., Tavakoli. F., 2004, Deciphering obliqueshortening of central Alborz in Iran using geodetic data, Earth and Plane-tary Science Letters, 223, 177-185.

• Vernant Ph., Nilforoushan F., Hatzfeld D., Abbassi M.R., Vigny C., Mas-son F., Nankali H., Martinod J., Ashtiani A., Bayer R., Tavakoli F., CheryJ., 2004, Present-day crustal deformation and plate kinematics in the Mid-dle East constrained by GPS measurements in Iran and northern Oman,Geophysical Journal International 157, 381-398.

5

• Bayer R., Chery J., Tatar M., Vernant Ph., Abbassi M., Masson F, Nil-foroushan F., Doerflinger E., Regard V. and Bellier O., 2006, Active de-formation in Zagros-Makran transition zone inferred from GPS measure-ments, Geophysical Journal International, 165, 373-381.

• Walpersdorf A., Hatzfeld D., Nankali H., Tavakoli F., Nilforoushan F.,Tatar M., Vernant P., Chery J., Masson F., 2006, Difference in the GPS de-formation pattern of North and Central Zagros (Iran), Geophysical JournalInternational, 167, 1077-1088.

• Schreurs G, Buiter S.J.HH, Boutelier D., Corti G., Costa E., Cruden A.R.,Daniel J.M., Hoth, S., Koyi H.A., Kukowski N., Lohrmann J., RavagliaA., Schlishe R.W., Withjack M.O., Yamada Y., Cavozzi C., DelventisetteC., Elder Brady J.A., Hoffmann-Rothe A., Mengus J.M., Montanari D.,Nilforoushan F., 2006, Analogue benchmarks of shortening and extensionexperiments, Geological Society Special Publication, Analogue and Nu-merical Modeling of Crustal-Scale Processes, SP253, pp. 1-27.

• Nilfouroushan F., 2006, GPS study of active tectonics in Iran (focusing onthe Zagros fold-thrust-belt, SW Iran), MPhil thesis, Uppsala University.

• Nilforoushan F., Talbot CJ., Fielding EJ., 2006, Preliminary investigationof Zagros thrust-fold-belt deformation using SAR interferometry, Proc.FRINGE 2005 Workshop, Frascati, Italy, 28 November – 2 December 2005(ESA SP-610, February 2006).

Reprints were made with permission from the publishers.

6

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Tectonic deformation measurements using analogue modeling, GPS

and InSAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.1 Analogue Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.2 Global Positioning System (GPS) . . . . . . . . . . . . . . . . . . . . . . 152.3 Synthetic Aperture Radar Interferometry (InSAR) . . . . . . . . . . 17

3 Summary of the Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.1 Paper I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.2 Paper II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223.3 Paper III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.4 Paper IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Summary in Swedish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1. Introduction

The Zagros fold-thrust belt in SW Iran is a zone of active convergence be-tween the Arabian and Eurasian plates and a favorite target for geoscientistsstudying rock and crustal deformation (Fig. 1.1). This belt and its forelandbasin in the Persian Gulf, host a large variety of geological structures and ahuge proportion of the world’s hydrocarbons (oil and gas) and is shaken dailyby moderate, and often hazardous earthquakes. The Hormuz salt layer actsas a weak decollement that decouples the cover sediments from the basementunderlying parts of the Zagros and ensures that much of the deformation isthin-skinned. The low density of the salt helps it to move upward in salt plugsdriven by gravity and the lateral tectonic forces shortening the Zagros. Thesalt plugs add to the attractions of the Zagros as a complex natural tectoniclaboratory.

Since the early 1950s, geoscientists have been trying to estimate rates ofdeformation in the Zagros. Lees & Falcon (1952) showed that a canal bedabout 1700 years old was deepened 12 ft (4 m) to take into account of theslow rise of the Shaur anticline. This situation can be interpreted to imply ananticlinal uplift rate of about 2.3 mm/yr. Falcon (1974) then inferred that theregional uplift represented by ‘geo-flexure’ implied that the Zagros had risenat a minimum rate of 1 mm/yr since the early Pliocene. Some of the first 14Cdates were applied to marine terraces uplifted along the Persian Gulf coast andindicated that the flanks of frontal anticlines in the Zagros rose episodicallyat rates of 0.7 mm/yr for about 7000 years after taken account the eustaticfactor (Vita-Finzi 1979). This was interpreted as implying a long-term averagerate of northeastward frontal shortening of about 6.8 mm/yr (Vita-Finzi 1979),close to the cumulative average propagation rate of about 10 mm/yr of theZagros front since the Eocene (34-55 Ma) (Hessami et al. 2001).

The large-scale folding and thrusting of the cover sequence depositedon the passive margin of Arabian plate indicates thin-skinned Zagrosdeformation whereas the seismic records indicate reverse faulting in theunderlying Panafrican basement implying a component of thick-skinnedshortening (Jackson and Fitch, 1981; Berberian, 1995).

The thesis argued here is that accurate monitoring of the current deforma-tion within the Zagros Mountains will help us understand the processes andmechanisms involved at young convergent plate-margins. The four papers thatsupport this thesis focus on 3 different approaches to monitoring strains in a

9

15

25

35

605040

15

25

35

605040

Arabian Plate

20 mm/yr

Eurasia

15 mm/yr

divergence

Zagros

converging zoneMakran prism

Central Iran

Figure 1.1: The study area (in rectangle) is in the convergence zone between Ara-bia and Eurasia. The Etopo2v2 topographic/bathymetric data (http://www.ngdc.noaa.gov/mgg/fliers/01mgg04.html) was used for this shaded relief map.The vectors show GPS velocities (Reilinger et al. 2006) relative to a Eurasia-fixedframe. Counterclockwise rotation of Arabia is also indicated.

plate convergence zone: GPS and InSAR (satellite geodetic data) and scaled-models simulating fold-thrust belts in the laboratory.

The first paper (I) presents the results of three campaigns of GPS measure-ments for the period February 1998 to June 2001 at 35 stations in and aroundthe Zagros. The main objective of this study is to directly sample horizon-tal movements within the Zagros belt due to continuing convergence betweenArabia and central Iran. My contributions to this paper were to help design,install and measure the GPS network. I carried out all the data processing,helped the data analysis, and wrote about half of the paper.

Paper II is devoted to study of the role of a deep salt decollement on surfacedeformation in a simulated fold-thrust belt (e.g. Zagros) by analysis of digitalimages of the surface of sand models laterally shortened in the laboratory. The

10

displacement fields and finite strain maps are illustrated and discussed. Forthis paper, my co-author schooled me the technique and designed the modelconfiguration which we set up together. I ran the models, made the measure-ments and wrote computer programs to process the data and interpret them. Iwrote most of the paper, and my co-author helped with the interpretation andimproved the manuscript.

Paper III continues the systematic study of the affects of different coeffi-cients of friction along the interface between a cover and basement in a modelfold-thrust belt. The deformations of three identical sandbox models with dif-ferent basal frictions were compared using an accurate laser-scanner. Here Ihelped design and set up the models. I deformed the models, collected andanalyzed the data and wrote most of the paper.

Paper IV investigates the surface deformation in coastal areas of the south-eastern Zagros and the nearby island of Qeshm using SAR interferometry. Alarge proportion of the total shortening across the southeastern Zagros occursclose to the Mountain Frontal Fault and we analyze a fault along SW QeshmIsland that may be a local equivalent. For this paper, I wrote the proposal toESA (European Space Agency) to access the satellite data, ordered all theappropriate SAR images and processed the data. I also helped interpret theresults and write the manuscript.

Two papers (I and IV) directly measure the rate of horizontal and verti-cal movements of rocks in and around the Zagros Mountains using geodeticsatellite data. The other two papers (II and III) use sandbox models to simu-late fold-thrust belts and relate the volumetric and surface strain to the type ofdecollement (viscous and frictional), Our modeling results are compared withpresent-day tectonics studied in the Zagros (the results of paper I) and the to-pography of the Zagros which are all affected by the presence or absence of asalt decollement.

As three different techniques were employed to generate the results dis-cussed in this research, the next section outlines each technique briefly to helpthe understanding of readers from different backgrounds.

11

2. Tectonic deformation measurementsusing analogue modeling, GPS andInSAR

2.1 Analogue ModelingSince the early 1800’s, geoscientists have used different versions of the orig-inal “mountain machine” (Fig. 2.1) (so called by Bailey Willis in 1891) tosimulate the mechanism of formation and evolution of geological processesand structures in analogue (also called physical) models in the laboratory.Analogue models improve our understanding of natural prototypes by usingproperly-scaled materials (brittle, ductile etc.), driving and resisting forces andboundary conditions. The advantage of analogue modeling is that the past,present and future of geological processes which affect strong rocks on largescales over geological times can be better understood and predicted by sys-tematically deforming weaker materials in smaller models over shorter timeintervals in the laboratory. Observing the formation of relevant model struc-tures during model deformation can help the recognition of similar processesforming similar structures in nature. Another advantage of physical modelingis the possibility of varying model parameters systematically and determiningtheir role on the kinematics and dynamics of the simulated processes.

To draw any conclusion from analogue models, there must be similarity be-tween the geometries, kinematics and dynamics of the models and their natu-ral prototypes. If angular relationships in the model are equal to their equiva-lents in nature, and if the lengths in the model are proportional to the naturalprototype, the geometries of the model and its natural target will be similar(Hubert 1937). For kinematic similarity, the geometrically similar model andprototype have to undergo similar changes of shape and/or position, where thetime required for any change in the model is proportional to the correspond-ing change in the prototype (Ramberg, 1967). Finally, for dynamic similaritybetween a model geometrically and kinematically similar with its prototype,the two bodies have to have similar ratios and distributions of different kindsof driving and resisting forces acting on the particles throughout both bodies(Schellart, 2002).

Analogue modeling has been carried out using the centrifuge technique(e.g., Ramberg, 1967; Dixon, 1974; Talbot 1977; Koyi 1988) and pure andsimple shear boxes (Malavielle 1984; Liu et al. 1992) or combinations of bothapproaches (Muluguta, 1988). Recent advances in the techniques used to mea-

13

Figure 2.1: Photograph of Cadell (1888) illustrating his pure-shear box, which he usedto deform layers of clay to study thrusts and folds (from Koyi 1997).

sure strains in analogue models have led to the need for the input parametersto be more accurate because these influence the kinematics and geometry ofthe model deformed in a large range of different machines. Similarly, the out-puts are now measured by such new techniques as Particle Image Velocimetry(PIV) (Wolf et al. 2003; Adam et al. 2005) or photogrammetry (e.g. Don-nadieu et al.2003; Fischer & Keating 2005). Digital images of models, high-precision laser measurements and tomography are also used to accurately mapthe geometry and kinematics of models. More accurate quantification of theinput and output parameters increases the reliability of comparing analoguemodels with numerical models to validate each technique or highlight the dif-ferences and investigate the causes of such differences to improve both tech-niques and, eventually, our simulation of nature.

Like all experimental techniques, analogue models have their restrictionsand simplify natural reality. Such limitations should be taken into accountwhen interpreting the results (Koyi 1997).

Papers II and III, use digital images of model surface and height measure-ments with an accurate laser scanner to monitor the deformations of sand mod-els designed to investigate the role of basal friction on surface and volumetricstrain in convergent settings.

14

2.2 Global Positioning System (GPS)GPS is one of the most popular systems of the GNSS (Global NavigationSatellite System) started in 1978 for military purposes. Soon after, GPS be-came available to civil users and opened an important era of accurate posi-tioning. Nowadays millimeter accuracies are achievable for measuring groundmovements due to such advances as the launching of more GPS satellites, thedevelopment of new algorithms for GPS signal processing in receivers andsoftware, better constraint of the reference frames, by the combination of dif-ferent geodetic techniques (e.g. VLBI, DORIS), better atmospheric modeling,and many other improvements involved in positioning. Such millimeter accu-racy allows geoscientists to study tectonic movements (McClusky et al. 2000;Vigny et al. 2002; Reilinger et al. 2006), postglacial uplifts (Sjöberg et al.2000; Johansson et al. 2002), volcanic-associated deformations (Owen et al.2000), landslides or subsidence (Motagh et al. 20007) and, in general, recog-nize active deforming zones and measure their strain rates.

Rather than explain the GPS system here (see e.g. Hoffman-Wellenhof et al.2001), I only outline the general approach to data gathering and a little moreabout processing.

There are two ways to collect GPS data appropriate for deformation studies.The first and the most accurate way is to use a suite of permanent GPS stationswhich continuously record the data. These precious measurements generatehuge amounts of data (usually 30-second samples) which make it possible toprocess and generate time series of the coordinates of the stations and con-clude the station movements on different time scales (e.g. daily, weekly, etc.)(Fig. 2.2).

The second (more usual) type of GPS deformation measurements capableof the appropriate horizontal accuracy is a campaign- (or survey-) mode. Anetwork of benchmarks is established in the study area and measured in thestatic-mode. This means that all GPS receivers remain stationary and recordthe GPS data simultaneously, usually for between 8 hours to 7 days dependingon many parameters that include the distances between stations. At least twocampaigns (over an appropriate time span chosen using prior knowledge ofdeformation rates in the area) of GPS measurements are carried out to estimatethe rate of movements of benchmarks in this time period. More campaignsover longer time period better constrain the velocity field of the study area(Fig. 2.2).

Establishing and managing networks of permanent GPS stations requireshuge investments and therefore campaign-mode measurements are more prac-tical for tectonic studies.

To achieve the high accuracy needed for deformation studies, collected GPSdata have to be processed to filter out various types of noise. There are twomain categories of software for GPS data processing; Vendor-supplied GPSdata processing software like the SKI, GPSurvey, Trimble Geomatics Office

15

Figure 2.2: Sample times series of a Permanent GPS station (e.g. BAHR, locatedin BAHRAIN, on the southern coast of the Persian Gulf, downloaded from http://sideshow.jpl.nasa.gov/mbh/series.html) which was used for dataprocessing in Paper I. Blue triangles exemplify three campaigns of GPS measure-ments, whereas discrete measurements in time are used to estimate the rate of move-ments (e.g. Paper I). It is obvious that more samples (generated from more GPS cam-paigns) spanning longer time intervals, better constrain rates of station displacement.The red lines are best fit linear trends for estimating rates of movements.

(TGO), etc., and scientific software developed by research organizations likeBernese (developed by AIUB), GIPSY (developed by JPL) and GAMIT (de-veloped by MIT), that provide different levels of accuracy. Examples of thefirst category of software are quick and user-friendly and used for local GPSnetworks. This category can be considered as black-box software where userscannot modify the code. Scientific equivalents of such software are used forlocal, regional and global networks on scales up to thousands of kilometersand include more mathematical models and options to update the time-relatedparameters (like different tides, polar motion/UT1, etc) to correct for differentsources of errors and end up with millimeter accuracies. Many settings andfiles should be prepared to processes GPS data. The initial files for examplefor GAMIT/GLOBK software (King and Bock, 2004) are:

16

• Table of satellite types (due to renumbering of the satellites)• Ephemeredes of Sun and Moon needed for tidal forces on satellites• Nutation tables that give the position of Earth’s body axis in space• Leap second table that allows conversion from GPS time to UTC• Polar motion/UT1 tables needed in the transformation from inertial to Earth

fixed frame• Ocean tide loading model tables• Antenna phase center model tables• GPS receiver and setup information (antenna and receiver type, antenna

height)• A priori coordinates and velocities for sites• Initial orbit information for satellites• Atmospheric and water loading (optional).

Together with these initial files, the collected GPS data are processed byGAMIT to estimate the station positions, satellite orbit parameters, Earth Ori-entation Parameters (EOP), time dependent Zenith delays and gradients, andcarrier phase ambiguities. There seldom enough receivers for measuring thewhole network simultanously, therefore there are usually several setups of re-ceivers, so loose daily solutions (h-files) are generated and finally adjusted inGLOBK (Herring, 2004) (GAMIT complement) to solve the complete set ofparameters for that campaign. To use the coordinates derived from these so-lutions, it is necessary to transform all the loosely constrained solutions intoa consistent reference frame so that rates of deformation can be derived fromthe time series (e.g. Fig. 2.2) of the station coordinates. To do this, campaignsolutions are combined in GLOBK and site velocities are estimated in any de-sired reference frame (defined by the user). Usually the accurate positions andvelocities of the IGS (International Geodynamic Service) of permanent globalGPS stations and their observations (or archived h-files) are used to constrainGLOBK solutions and realize the reference frames.

The formal errors are usually not considered as real uncertainties. Someerror analysis has to be done to assess the reliability of the results. Theseinclude for example, the independent evaluation of coordinate repeatabilities(i.e. the rms of the independent measurements about their mean value) of dailyand campaign solutions for each station and compare the results with othersolutions from other studies.

2.3 Synthetic Aperture Radar Interferometry (InSAR)The potential of Synthetic Aperture Radar interferometry (InSAR) to detectand measure tectonic and non-tectonic deformation of the Earth’s surface hasbeen confirmed by many studies of such phenomena as earthquake deforma-tion (e.g. Massonnet and Feigl 1998, Wright et al. 1999, Wang et al. 2004,

17

Pathier et al. 2006), land subsidence around and above mines and hydrocar-bon fields (Fielding et al. 1998), landslides (Singhroy et al. 1998), and volca-noes (Feigl et al. 2000). Emergent salt diapirs are also good targets for InSARstudies to investigate if they are active and then estimate their rate of rise(Weinberger et al. 2006).

Graham (1974) first outlined the principles of InSAR (from Raucoules et al.2007). An area of the Earth’s surface is scanned by radar (Radio detection andranging) waves transmitted by radar systems in satellites (or aircraft) and thereflected waves that bounce back are recorded. The amplitude and phase ofthe waves reflected from the ground surface (covering approximately 10,000km2) are recorded via satellite antenna and make two-dimensional complexmatrices called SAR images (Fig. 2.3). Having at least two images taken atdifferent times, the phase value in one image can be subtracted from that ofthe other, for the each point on the ground (or pixel in image). This, in effect,generates the interference between the two phase signals and is the basis ofinterferometry.

SAR systems in satellites like ERS1, ERS2, ENVISAT, RADARSAT andALOS mostly operate on wavelengths in the upper L band, C band, or X band(i.e. ranging roughly between 1.2 and 10.9 GHz). The repeat cycle (the tem-poral spacing between successive image acquisitions) is different for differentsatellites i.e. 35 days for ERS1 & 2 and ENVISAT, 24 days for Radarsat1and 46 days for ALOS. Shorter repeat cycles provide more information withthe potential for mapping pre-, co- and post-deformation associated with anyparticular geophysical phenomenon like an earthquake.

Differential interferometry (repeat-pass) is used to map any deformation ofthe ground surface. The repeat-pass interferometry method can involve the 2-pass, 3-pass or 4-pass methods (see Hanssen 2001 for 3- and 4-pass methods).The popular 2-pass method only uses two SAR images and thus producesjust one interferogram. Another interferogram is synthesized from an existingdigital elevation model (DEM) of the area (using orbital state vectors). Thesynthesized interferogram is then subtracted from the original interferogram,and the remaining residuals represent surface displacements (plus noise dueto atmospheric artefacts, residual orbital component and the DEM). The dis-placements are in line of sight (LOS) direction which sub-parallels the verticalmovements.

Geocoding is executed to transform the data for each pixel within an inter-ferogram (raster), to geodetic coordinates, e.g. latitude and longitude or any xand y in any particular map projection system, like UTM.

InSAR has many advantages including:• It generates a deformation map (usually 10000 km2) rather than sampling

a small number of points dispersed on the ground surface as with GPS.• There is no need for direct field measurements, only archived data are used

to investigate the deformation of any deforming phenomena.

18

Figure 2.3: An InSAR image is constructed from two satellite passes, both ofwhich record the phase of a radar wave return for each pixel. For a known radarwavelength, the phase differences reveal the relative displacements during the timeinterval between satellite passes. (Ref: http://edc.usgs.gov/Tectonic/tectonics_main.htm)

• The archived data acquired by the ERS1&2 satellites since 1992 and EN-VISAT, RADARSAT are already available to analyze past phenomena likeearthquakes, land subsidence etc (and the new ALOS will extend futurecoverage). These archived images can also be used to act as reference datato map future deformation of any sudden ground movements attributed to(e.g.) an earthquake.As well as the advantages mentioned above, it is also worth mentioning

that temporal and spatial coverage of SAR images suitable for deformationstudies are limited. Furthermore, changes of atmospheric and ground-coverconditions reduce the correlation (or coherency) between two SAR imagestaken at different times and therefore limit the data appropriate for SAR Inter-feromtery.

This thesis uses SAR interferometry to study recent deformation in the SEZagros and detects differential movements across the southwestern part ofQeshm Island.

19

3. Summary of the Papers

3.1 Paper IPaper I specifically addresses the question of present crustal movementsacross and along the Zagros mountain belt using GPS measurements.Previous GPS studies of Iran covered either a smaller area of the Zagros(Tatar et al. 2002) or the whole country (Nilforoushan et al. 2003; Vernant etal. 2004) but at much lower density than here.

The results of GPS data at 35 stations in and in the vicinity of the Zagrosfold-thrust belt are presented and interpreted for three campaigns in 1998,1999 and 2001. The GPS velocity fields relative to Eurasia and Arabia (Fig.3.1 ) are estimated. These velocities show clearly the change in character ofdeformation along the strike of the belt.

Figure 3.1: GPS horizontal velocities and their 95% confidence ellipses in the Arabia-fixed reference frame for the period 1998–2001. The velocities were estimated usingthe Euler vector calculated by Vernant et al. (2004) to show the present-day short-ening in the Zagros. The very small velocities (at the level of our ±3 mm/yr errorestimates) of the stations close to the Persian Gulf suggest that shortening diminishessouthwestwards in the Zagros fold-thrust belt.

21

Most of the shortening in the NW Zagros seems to occur along the Moun-tain Front Fault with its major earthquakes as well as along the Zagros frontcharacterized by smaller earthquakes. The change in direction and magnitudeof the velocity vectors across the north–south-trending Kazerun and Karebasfaults involves extension of up to 4 mm/yr along the strike of the Zagros belt(Figs. 3.1).

3.2 Paper IIA sandbox model consisting of two adjacent mechanically different decolle-ments (frictional and viscous) loosely simulated the southeastern part of theZagros fold-thrust belt. Digital images of the model surface are used to coor-dinate passive markers on the surface and quantify displacement fields and es-timate 2-D finite strains. These analyses show that, mapped in a fixed coordi-nate system, the deformation front propagates at different rates above the twodecollements. Displacements above a viscous decollement decrease graduallytowards the foreland, whereas they decrease sharply in front of the frontalthrust above the frictional decollement. Strain analyses of the model surfaceat different stages of deformation also show that cumulative strain is moreheterogeneous above the viscous decollement where strain domains are sep-arated by fault zones. Maps of displacement fields, finite strain ellipses (Fig.3.2) and dilatation also differ in character above the two decollements. Posi-tive dilatation (for cells with 12 × 12 mm dimensions) of about 50 ± 5 percent is observed above the proximal and distal ends of the viscous decolle-ment while no positive dilatation is recorded above the frictional decollement.The high surface extension above the viscous decollement is due to the vis-cous layer shortening and thickening beneath the sand overburden. Above thefrictional decollement, 12 × 12 mm cells recorded penetrative strains of up to18 ± 5 per cent due to lateral compaction. Consequently, volume decreasedabove the frictional decollement through porosity reduction. This volume re-duction should be taken into account during analyses of geological balancedSections.

Our analyses also show that the estimated finite strain depends not only onthe density of the marker points chosen for the analysis, but also their ini-tial distribution relative to the structures. This comparison shows that markerdensity limits measuring the actual strains in a heterogeneously deformingfold-thrust belt. The similarity of our model with nature is examined by com-parison with a recent GPS study in the Zagros fold-thrust belt and shows thata weak salt decollement causes divergent movement in the sedimentary coverin SE Zagros, as in the models.

22

x

y

e1=0, e2=-0.3

29.5% b

ulk sh

ort.

Figure 3.2: Finite strain ellipses (of cells with initial dimensions of 12mm x 12mm)superimposed on the last image of model surface after 29.5% bulk shortening. Princi-pal strains are scaled up by 30, and only e2 principal strain axis is shown for simplic-ity. Vacant areas indicate lost markers (e.g. overridden by imbricate thrusts). Ellipseswithout axes are the cells with very low strain (|e1| and |e2| are less than 0.05).

23

3.3 Paper IIIThis paper used sub-millimetric height measurements generated by a laserscanner to systematically study the influence of basal friction on surface andvolumetric strain in models of fold-thrust belts and accretionary prisms. Ourresults indicate that, in addition to influencing the kinematics and geometry ofthe wedge, there are direct correlations between volume reductions and basalfriction. After 16.3% bulk shortening, the volume decreased 5 ± 0.5%, 9.5 ±0.5% and 12.5 ± 0.5 % in the models shortened above low, intermediate andhigh friction decollements, respectively. This means that increasing the basalfriction increases the volume reduction.

Applied to nature, our model results indicate that compaction and penetra-tive strain is expected to be greater in fold-thrust belts shortened above high-friction decollement than in fold-thrust belts shortened above weak decolle-ments.

These model results also show that surface strain is increasingly localizedas friction along the basal decollement increases. Accurate height measure-ments show that the deformation front is much further forward than the frontalthrusts usually considered as the deformation front, especially in our low-frictional models (Fig. 3.3).

Our height measurements (±0.1 mm) reveal that our experimental wedgesdeveloped and maintained double tapers throughout their shortening, partic-ularly in the low-frictional model. Profiles across the Zagros fold-thrust beltshow a similar dependence of topography and taper on basal friction as pro-files along our models.

3.4 Paper IVThis study uses InSAR to look for and study individual structures that ac-commodate the high rate of deformation across the Southeast Zagros. Afteratmospheric effects in the high mountains of the Zagros frustrated our pre-liminary efforts, we refocused our attention on the coastal area with low re-lief where no comparable geodetic work had yet been carried out. We docu-ment the most interesting active structure we encountered: a newly recognizedfault with a trace along the length of Qeshm Island that parallels the strikeof nearby Zagros anticlines and may represent the local Zagros deformationfront (Fig. 3.4). We estimate the differential uplift rate across what we referto as the Qeshm fault as 8 ± 4 mm/yr between 1996 and 1999. The Qeshmfault indicates thick-skinned shortening if the 2005 earthquake occurred in thebasement further east on the same fault. Thick-skinned shortening would alsoexplain the low shortening rate across Qeshm Island indicated by GPS results.

By integrating the InSAR results with the geology of Qeshm we infer thatthe advance of the Zagros deformation front through Qeshm Island has only

24

AB

C

mm

com

pres

sion

4

Figu

re 3

.3:

A-C

are

per

spec

tive

imag

es o

f th

e to

pogr

aphy

of

the

scan

ned

area

(sh

own

in D

) in

mod

els

with

low

, int

erm

edia

te a

nd h

igh

basa

l fri

ctio

n re

spec

tivel

y af

ter

16.3

% (

8 cm

) bu

lk s

hort

enin

g. T

he d

e-fo

rmat

ion

fron

t pro

paga

tes

rapi

dly

in th

e m

odel

s w

ith lo

w b

asal

fric

tion

and

do n

ot fo

rm th

e hi

gh w

edge

of m

odel

s w

ith h

ighe

r bas

al fr

ictio

n. A

xes

in A

, B, a

nd C

are

in m

m.

25

450 m

m

lase

r mon

itorin

g

wed

ge to

p

fixed

wal

l

(mai

n de

form

ing

area

)

490 mm

D

com

pres

sion

P1

hei

gh

t (m

)

P2

P3

P1

P2

P3

up

lift

rate

(mm

/yr)

up

lift

rate

(mm

/yr)

up

lift

rate

(mm

/yr)

hei

gh

t (m

)h

eig

ht

(m)

pixels ( x 41 m)pixels ( x 10 m)

P1

p2

p3

A

B

C

D

E

F

G

-

Figure 3.4: A) DEM (10 m resolution) of the SW end of Qeshm locating the profiles inB-D as NS dashed lines. Curved dashed line indicates trace of the Qeshm fault resultedfrom SAR results. Heights are in meters (±7 m). Bars indicate location of the traceof the Qeshm fault inferred from InSAR results in E-G. E-G: LOS movement rates(in mm/yr) along the same profiles as B-D. Note that topography does not generallycorrelate with uplift rate. Blue dashed lines indicate a smooth topographic surfacethat may have been folded by reactivation of the Qeshm anticline in an unknowntime interval. Open white square represents the reference area used for calibrationof interferograms for comparison.

26

recently resumed after having been interrupted by Pleistocene-Holocene ma-rine erosion.

27

4. Conclusions

This thesis uses state-of-the-art geodetic satellite measurements to improveour knowledge of present-day active tectonics in the Zagros which were pre-viously studied mainly by geological or geophysical measurements. It alsouses sandbox simulations to investigate the affect of the basal friction and thepresence or absence of a salt layer between the cover and basement in thedeformation of fold-thrust belts like the Zagros.

Three campaigns of GPS measurements in 1998, 1999 and 2001 provided avelocity field (accurate to ±3 mm/yr) across and along the Zagros Mountains.These results have improved the constraint on the rate and direction of move-ments and the distribution of deformation in this fold-thrust belt. These GPSvelocities are assumed to be constant inter-seismic displacement rates andundisturbed by instantaneous co-seismic displacements due to nearby earth-quakes during the time intervals covered by the successive surveys. The con-tribution of seismic strains to total strains deduced from GPS measurementsis relatively small.

The dense velocity field obtained from three campaigns of GPS measure-ments within the Zagros Mountains shows clearly for the first time the changein character of deformation across the Kazerun Fault. East of this fault, thevelocity vectors trend approximately north–south, nearly perpendicular to thearcuate trend of the local Zagros folds. However, west of the Kazerun Faultthe velocity vectors are oblique to the linear trend of the mountain belt and itsinternal folds. The current rate of shortening across the SE Zagros is about 9± 3 mm/yr, whereas in the NW Zagros it is about 5 ± 3 mm/yr.

The along-strike extension of the Zagros belt across the Kazerun and Kare-bas faults implies that the deformation in this mountain belt is not accommo-dated by simple across-strike shortening and thickening.

The different strain distributions across and along the Zagros are partly at-tributed to different parts of the contact between the cover and basement hav-ing different coefficients of friction. This concept was tested by laboratoryexperiments.

Two studies systematically investigated the role of basal friction in thin-skinned tectonics. The first used a ductile layer beside a frictional decollementin a shortened sandbox (paper II), and the second study (paper III), simulatedconvergent settings above low, intermediate and high-basal frictional decolle-ments without a ductile layer. Paper II measured significant local extensionparallel to the bulk shortening direction above the anticlines forming above

29

the model “salt” decollement but not above frictional decollement. Similarnorth-south extension may affect the top surfaces of natural anticlines coredby salt.

The penetrative and finite strains and the advance rate of the deformationfront were very different above the two decollements. The approach adoptedfor paper III differed from that in paper II by applying a laser-scanner. The re-sulting accurate height measurements allowed us to monitor the propagationof the deformation front and locate it much further forward than expected inmodels with low-frictional decollements. Double wedges and tapers in thesemodels were recognized for the first time. The geometries of model wedgesand tapers differed significantly and the volume reductions were directly pro-portional to their basal frictions.

Paper IV showed that part of Qeshm Island is uplifting at a rate of 8 ±4 mm/yr despite the available GPS results (observed on Oman and north ofQeshm Island about 150 km away) implying that no significant shortening isoccurring in the sector of the Strait of Hormuz that includes Qeshm Island.We resolve this apparent paradox by arguing that the usual mechanisms bywhich the Zagros deformation front advances were interrupted by Pleistoceneand Holocene marine erosion of the Qeshm thrust anticline.

The results of these four research works can be applied to many other fold-thrust belts to different degrees. Paper I and VI are specifically about the Za-gros fold-thrust belt while the other two are related but more general.

Future more detailed mapping of Zagros deformation will be helpedby such geodetic techniques as precise leveling, SAR Interferometry andmore dense local GPS networks. All the data produced by these approachesshould be integrated with the data generated by permanent GPS stations(http://www.ncc.org.ir/) recently added in and around the belt by NCC.

Linking geodetic studies to other geological and geophysical investigationsshould improve understanding of this complex deforming zone.

30

5. Summary in Swedish

Geodetiska satellitdata har använts för att mäta den pågående deformationeninom Zagrosbergskedjan i sydvästra Iran. En form av geodetiska mätningaranvänds också för att i modellskala studera karaktären av deformationen vidjordytan i den typ av konvergenta plattmiljöer som representeras av Zagros.Global Positioning System (GPS) mätningar i tre omgångar mellan 1998 och2001 indikerar årliga förkortningar på 9 ± 3 mm/år tvärs över sydöstra och5 ± 3 mm/år tvärs över nordvästra delarna av Zagrosbergen. Förutom olikahastigheter och riktningar på var sida om den nord-sydliga Kazerun förkast-ningen, förekommer också lokalt sträckning längs bergskedjan i dess östradel.

Differentiella SAR interferogram baserade på ERS 1 & 2 (satellitdata) in-samlade mellan 1992 och 1999 påvisar en upphöjning på 8 ± 4 mm/år längsen nyupptäckt förkastning på ön Qeshm. Detta orsakas av ett brantståendeimbrikationssystem som möjligen även i dag representerar den lokala defor-mationsfronten för Zagros.

Saltdiapirerna i östra delen av Zagros stiger från ett lager som verkar som endislokationsyta med låg friktion och som därigenom frikopplar deformationeni ovanpåpliggande sedimentbergarterna från deras underlag medan sedimen-bergarterna i den västra delen vilar på och deformeras ovanpå en dislokation-syta med hög friktion. Av den anledningen gjordes fysikaliska, analoga mod-eller av ytbergarternas deformation inom Zagros genom att förkorta sandlagerovanpå dislokationsytor med hög respektive låg friktion där ytorna represen-terades av mjuka lager med olika viskositet. Modellerena visade att strain-fördelningen blir olika ovanpå de olika typerna av dislokationsytor; med salt(låg friktion) blir deformationen mer heterogen och lokal extension i förkort-ningsriktningen blir dominant.

I en separat undersökning studerades också systematiskt hur variationen ifriktion vid basen inverkar på ovanpåliggande deformation inom konvergentamiljöer. Exakta höjmätningar av modellernas yta med laserscanner påvisadeen deformationsfront på större avstånd än väntat, speciellt när när friktionenvid basen var låg. Volymsminskningen i våra sandmodeller visade en direktkorrelation med friktionen i det basala lagret.

31

Acknowledgement

In 1997, I was working at NCC (National Cartographic Center of Iran) whenKhaled Hessami (a previous PhD student at Uppsala) made a great suggestionto me: Establish a GPS network in the Zagros. As my main interest includessuch GPS networks, and as I dreamed of writing a research article in an in-ternational journal, I welcomed his suggestion and worked with him to carryout the job. This established my first connection with Uppsala University andwork indirectly with my future supervisor Prof. Christopher Talbot. This co-operation eventually led to the Swedish Research Council (VR) funding myPhD studies. Therefore, my first great thanks go to Khaled Hessami and mysupervisor, Christopher Talbot and for their help to initiate and improve myPhD proposal. Beside this initial great help, I am also grateful to my super-visor who shared his valuable knowledge, experience and time to teach memany lessons by helpful and constructive discussions, reviews, and commentson my articles. He always encouraged me to think critically. He supported mein many ways including financing me attending international meetings, sum-mer schools and workshops where I had the chance to present my work, and tolisten and learn from others. Chris loves salt tectonics and all my manuscriptsare related somehow to surface deformation above salt. Although I am not ageologist, I am close to falling in love with salt tectonics too! My great thanksalso go to his wife, Rosemary, for her kindness to our family and her suggest-ing that my son, Shayan, attends the International school at Uppsala.

Professor Hemin Koyi, my second advisor, is also greatly acknowledged.His office door was always open to me for helpful discussions. With his greatexperience in the field and laboratory, Hemin taught me analogue modeling.For me, learning this field of science was so different from my geodetic back-ground that it opened a new window to look at the evolving Earth. It helpedme to imagine how different parameters can change the deformation regimesin models and their natural prototypes. Thanks very much Hemin!

Taher Mazloomian is heartily thanked for helping my family from the firsthours of our arrival at Uppsala. He helped in many ways, especially our set-tlement. We had many good times with him and his family over the last 4years.

Abbas Bahroudi and Mohamed Kalefa are warmly thanked for helping withour accommodation at Uppsala in the first year. I thank my colleagues andfriends in Iran: Mohamed Madad, Mohamed Sarpulki, Esmail Emtiaz, FarokhTavkoli, Yahya Djamour, Hamid Nankali, Morteza Sedighi, Mahmood Sar-

33

dari, Khosro Nazari, and many others at NCC who helped with data and othersupport for these studies. Special thanks go to the field workers who collectedthe valuable GPS data in the difficult topography of the Zagros.

I can not possibly compensate my wife (Tabasom) and son (Shayan) forall the time (and love!) which I spent on my thesis but should have sharedwith them. This work could not have been finished without the valuable pa-tience and support provided by Tabasom and Shayan. The continuous supportand encouragement to study at higher levels provided by my Father, Motherand elder brother (Farshid) are greatly appreciated. My mother- and brothers-in-law, especially Mehrdad Javanbakht, are acknowledged for their help andpatience.

My Iranian friends at Uppsala: Nasser Matori, Mehrdad Bastani, BehroozOskooi, Hossein Shomali, Ahmadreza Roozbeh, Afshin Ferdowsi, HesamKazemeini, Alireza Malehmir, Majid Beiki, Saeid Amiri, and their familiesare warmly thanked for help and sharing their time with us.

My former and present friends and colleagues in the Solid Earth Researchgroup, Sadoon Morad, Örjan Amcoff, Hans Annersten, Hans Harryson,Per Nysten, Peter Lazor, Håkan Sjöström, Tore Eriksson, Per Nysten, UlfAndersson, Mohamed El-ghali, Howri Mansurbeg, Zurab Chemia, KhalidAl-Ramadan, Masoumeh Kordi, Erik Ogenhall, Sofia Winell, ZuzanaKonopkova, Kristina Zarins, J.D. Martín-Martín, Sara Carlsson, OsamaHelal, Ashour Abouessa, Lijam Hagos Zemichael, Tuna Eken, are thankedfor creating such a friendly working environment. Special thanks go to KerstiGløersen for her administrative help. I am also very grateful to Taher, Anna,Johan, and Leif for all the help with printing and technical issues. ZurabChemia, my roommate at the department, helped me very much with manythings, especially with his great knowledge of computer, mainly Linux. Healso helped me format my thesis at the final stage.

There are many other friends, colleagues, professors at Uppsala and those,too many to list, that I visited and had discussions with at different meetingsand International conferences. They all participated in my success in reachingthis point and I thank all of them profoundly.

34

Bibliography

J. Adam (2005). ‘Shear localization and strain distribution during tectonic fault-ing, new insights from granular-flow experiments and high-resolution optical imagecorrelation techniques’. Journal of Structural Geology 27:283–301.

M. Berberian (1995). ‘Master blind thrust faults hidden under the Zagros folds:active basement tectonics and surface morphotectonics’. Tectonophysics 241:193–224.

S. Dixon, J.M. & Liu (1974). ‘Centrifuge modeling of the propagation of thrustfaults’. In: McClay, R.R. (Ed.) Thrust Tectonics. Chapman and Hall, Londonpp. 53–69.

F. Donnadieu, et al. (2003). ‘Digital photogrammetry as a tool in analogue modeling:applications to volcano instability’. Journal of Volcanology and GeothermalResearch 123:161–180.

N. Falcon (1974). ‘Southern Iran: Zagros Mountains’. In: A. Spencer (Ed.),Mesozoic-Cenozoic Orogenic Belts, Geological Society of London, SpecialPublication 4:199–211.

K. Feigl, et al. (2000). ‘Crustal deformation near Hengill volcano, Iceland 1993-1998: Coupling between magmatic activity and faulting inferred from elastic mod-eling of satellite radar interferograms’. Journal of Geophysical Research-solidEarth 105:25655–25670.

E. Fielding, et al. (1998). ‘Rapid subsidence over oil fields measured by SARinterferometry’. Geophys. R. L. 25(17):3215–3218.

M. Fischer & D. Keating (2005). ‘Photogrammetric techniques for analyzing dis-placement, strain, and structural geometry in physical models: Application to thegrowth of monoclinal basement uplifts’. Geol. Soc. Am. Bull. 117:369–382.

R. Hanssen (2001). ‘Radar Interferometry: Data Interpretation and Error Analysis’.Kluwer Academic Publishers, Netherlands p. 308.

T. Herring (2004). ‘GLOBK: Global Kalman filter VLBI and GPS analysis pro-gram version 4.1, Mass’. Inst. of Technol. Cambridge .

K. Hessami, et al. (2001). ‘Progressive unconformities within an evolving forelandfold–thrust belt, Zagros Mountains’. Journal of the Geological Society, London158:969–981.

35

B. Hoffman-Wellenhof, et al. (2001). ‘GPS theory and practice’. 5th edn.Springer, Berlin Heidelberg New York 158:67.

M. Hubbert (1937). ‘Theory of scale models as applied to the study of geologicstructures’. Geological Society of America Bulletin 48:1459–1520.

J. Jackson & T. Fitch (1981). ‘Basement faulting and the focal depths of the largerearthquakes in the Zagros Mountains (Iran)’. Geophys. J. R. astr. Soc. London64:561–586.

J. Johansson, et al. (2002). ‘Continuous GPS measurements of postglacial adjust-ments in Fennoscandia–1. Geodetic results’. J. Geophys Res. 107(B8):2157.

R. W. King & Y. Bock (2004). ‘Documentation of the MIT GPS analysis software:GAMIT’. Mass. Inst. of Technol., Cambridge .

H. Koyi (1988). ‘Experimental modeling of role of gravity and lateral shortening inZagros mountain belt’. AAPG Bulleten 72:1381–1394.

H. Koyi (1997). ‘Analogue modelling; From a qualitative to a quantitative technique,a historical outline’. Journal of Petroleum Geology 20:223–238.

G. Lees & N. Falcon (1952). ‘The geographical history of the Mesopotamian Plains’.Geographical Journal 118:24–39.

H. Liu, et al. (1992). ‘Physical models of thrust wedges’. In: McClay, K.R., (Ed.),Thrust Tectonics, Chapman and Hall, London pp. 71–81.

J. Malavieille (1984). ‘Modélisation expérimentale des chevauchements imbriqués:application aux chaînes de montagnes’. Bulletin de la Société Géologique deFrance 7:129–138.

D. Massonnet & K. Feigl (1998). ‘Radar interferometry and its application tochanges in the earth’s surface’. Reviews of Geophysics 36:441–500.

S. McClusky, et al. (2000). ‘Global positioning system constraints on plate kine-matics and dynamics in the eastern Mediterranean and Caucasus’. J. Geophys Res.105:5695–5719.

M. Motagh, et al. (2007). ‘Land Subsidence in Mashhad Valley, northeast Iran:Results from InSAR, Leveling and GPS’. Geophysical Journal International168:518–526.

G. Mulugeta (1988). ‘Modelling the geometry of Coulomb thrust wedges’. Journalof Structural Geology 10:847–859.

F. Nilforoushan, et al. (2003). ‘GPS network monitors the Arabia-Eurasia collisiondeformation in Iran’. Journal of Geodesy 77:411–422.

36

S. Owen, et al. (2000). ‘Rapid deformation of Kilauea Volcano: global positioningsystem measurements between 1990 and 1996’. J. Geophys Res. 105(B8):18983–18998.

E. Pathier, et al. (2006). ‘Displacement field and slip distribution of the 2005 Kash-mir earthquake from SAR imagery’. Geophysical Research Letters , L20310,doi:10.1029/2006GL027193. 33.

H. Ramberg (1967). ‘Model experimentation of the effect of gravity on tectonic pro-cesses’. The Geophysical Journal of the Royal Astronomical Society 14:307–329.

D. Raucoules, et al. (2007). ‘Use of SAR interferometry for detecting and assessingground subsidence’. Geoscience, doi:10.1016/j.crte.2007.02.002. .

R. Reilinger, et al. (2006). ‘GPS Constraints on continental deformation inthe Africa-Arabia-Eurasia continental collision zone and implications for thedynamics of plate interactions’. Journal Geophysical Research letters,(B5),doi:10.1029/2005JB004051. 111.

W. Schellart (2002). ‘Analogue modelling of large-scale tectonic processes: an in-troduction’. In: Schellart , W. P. and Passchier, C. 2002. Analogue modellingof large-scale tectonic processes. Journal of the Virtual Explorer 7:1–6.

V. Singhroy, et al. (1998). ‘Landslide characterisation in Canada using interfero-metric SAR and combined SAR and TM images’. Advances in Space Research21:465–476.

L. Sjöberg, et al. (2000). ‘Glacial rebound near Vatnajokull, Iceland, studied byGPS campaigns in 92 and 96.’. Journal of Geodynamics 29:63–70.

C. Talbot (1997). ‘Centrifuge models of Gulf of Mexico profiles’. Marine andPetroleum Geology 9:412–432.

M. Tatar, et al. (2002). ‘The present-day deformation of the central Zagrosfrom GPS measurements’. Geophysical Research Letters, doi: 10.1029/2002GLO15427 29.

P. Vernant, et al. (2004). ‘Present-day crustal deformation and plate kinematics inthe Middle East constrained by GPS measurements in Iran and northern Oman’.Geophysical Journal International 157:381–398.

C. Vigny, et al. (2002). ‘GPS network monitors the Western Alps over a five yearperiod: 1993–1998’. Journal of Geodesy 76:63–76.

C. Vita-Finzi (1979). ‘Rates of Holocene folding in the coastal Zagros near BandarAbbas Iran’. Nature 278:632–634.

37

R. Wang, et al. (2004). ‘The 2003 Bam (SE Iran) earthquake: precise source pa-rameters from satellite radar interferometry ’. Geophysical Journal International159:917–922.

R. Weinberger, et al. (2006). ‘Mechanical modeling and InSAR measure-ments of Mount Sedom uplift, Dead Sea basin: Implications for effectiveviscosity of rock salt’. Geochemistry Geophysics Geosystems, Q05014,doi:10.1029/2005GC001185. 7.

H. Wolf, et al. (2003). ‘Experimental investigation of shear band patterns in granularmaterial’. Journal of Structural Geology 25:1229–1240.

T. Wright, et al. (1999). ‘Source parameters of the 1 October 1995 Dinar (Turkey)earthquake from SAR interferometry and seismic body wave modelling’. Earthand Planetary Science Letters 172:23–37.

38

Acta Universitatis UpsaliensisDigital Comprehensive Summaries of Uppsala Dissertationsfrom the Faculty of Science and Technology 318

Editor: The Dean of the Faculty of Science and Technology

A doctoral dissertation from the Faculty of Science andTechnology, Uppsala University, is usually a summary of anumber of papers. A few copies of the complete dissertationare kept at major Swedish research libraries, while thesummary alone is distributed internationally through theseries Digital Comprehensive Summaries of UppsalaDissertations from the Faculty of Science and Technology.(Prior to January, 2005, the series was published under thetitle “Comprehensive Summaries of Uppsala Dissertationsfrom the Faculty of Science and Technology”.)

Distribution: publications.uu.seurn:nbn:se:uu:diva-7928

ACTAUNIVERSITATISUPSALIENSISUPPSALA2007