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  • 1. Buiter, S.
    et al.
    Schreurs, G.
    Albertz, M.
    Beaumont, C.
    Burberry, C.
    Callot, Jean-Paul
    Cavozzi, C.
    Cerca, M.
    Chen, J. H.
    Cristallini, E.
    Cruden, A.
    Cruz, L.
    Cooke, M.
    Daniel, J. M.
    Egholm, D.
    Ellis, S.
    Gerya, T.
    Hodkinson, L.
    Hofmann, F.
    Garcia, V. H.
    Gomes, C.
    Grall, C.
    Guillou, H.
    Guzmán, C.
    Nur Hidayah, T.
    Hilley, G.
    Kaus, B.
    Klinkmüller, M.
    Koyi, H.
    Uppsala universitet, Berggrundsgeologi.
    Lazor, Peter
    Uppsala universitet, Berggrundsgeologi.
    Lu, C. Y.
    Macauley, J.
    Maillot, B.
    Meriaux, C.
    Mishin, Y.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Pan, C. C.
    Pascal, C.
    Pillot, D.
    Portillo, R.
    Rosenau, R.
    Schellart, W. P.
    Schlische, R.
    Soulomiac, P.
    Take, A.
    Vendeville, B.
    Vettori, M.
    Vergnaud, M.
    Wang, S. H.
    Withjack, M.
    Yagupsky, D.
    Yamada, Y.
    Benchmarking the Sandbox: Quantitative Comparisons of Numerical and Analogue Models of Brittle Wedge Dynamics2010Konferansepaper (Fagfellevurdert)
  • 2.
    Carrillo, Emilio
    et al.
    Departament de Geoquímica, Petrologia i Prospecció Geològica, Universitat de Barcelona, Barcelona, Spain; School of Geological Sciences and Engineering, Yachay Tech University, San Miguel de Urcuquí, Ecuador.
    Koyi, Hemin
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Lantmäteriet, Gävle, Sweden.
    Structural significance of an evaporite formation with lateral stratigraphic heterogeneities (Southeastern Pyrenean Basin, NE Spain)2017Inngår i: Marine and Petroleum Geology, ISSN 0264-8172, E-ISSN 1873-4073, Vol. 86, s. 1310-1326Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We run a series of analogue models to study the effect of stratigraphic heterogeneities of an evaporite formation on thin-skinned deformation of the Southeastern Pyrenean Basin (SPB; NE Spain). This basin is characterized by the existence of evaporites, deposited during the Early-Middle Eocene with lateral variations in thickness and lithological composition. These evaporites are distributed in three lithostratigraphic units, known as Serrat Evaporites, Vallfogona and Beuda Gypsum formations and acted as décollement levels, during compressional deformation in the Lutetian. In addition to analogue modeling, we have used field data, detailed geological mapping and key cross-sections supported by seismic and well data to build a new structural interpretation for the SPB. In this interpretation, it is recognized that the basal and upper parts of the Serrat Evaporites acted as the main décollement levels of the so-called Cadí thrust sheet and Serrat unit. A balanced restoration of the basin indicates that thrust faults nucleated at the stratigraphic transition of the Serrat Evaporites (zone with lateral variations of thickness and lithological composition), characterized by a wedge of anhydrite and shale. The analogue models were setup based on information extracted from cross-sections, built in two sectors with different lithology and stratigraphy of the evaporites, and the restored section of the SPB. In these models, deformation preferentially concentrated in areas where thickness change, defined by wedges of the ductile materials, was inbuilt. Based on the structural interpretation and model results, a kinematic evolution of the SPB is proposed. The kinematic model is characterized by the generation of out-of-sequence structures developed due to lateral stratigraphic variations of the Serrat Evaporites. The present work shows a good example of the role of stratigraphic heterogeneities of an evaporite formation which acts as décollement level on structural deformation in a fold-thrust belt. The results of this work have implications for hydrocarbon exploration and are relevant for studying structural geometry and mechanics in shortened evaporite basins.

  • 3.
    Deng, Hongling
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Koyi, Hemin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Superimposed folding and thrusting by two phases of mutually orthogonal or oblique shortening in analogue models2016Inngår i: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 83, s. 28-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Orogens may suffer more than one phase shortening resulting in superposition of structures of different generations. Superimposition of orthogonal or oblique shortening is studied using sandbox and centrifuge modelling. Results of sand models show that in orthogonal superimposition, the two resulting structural trends are approximately orthogonal to each other. In oblique superimposition, structures trend obliquely to each other in the relatively thin areas of the model (foreland), and mutually orthogonal in areas where the model is thickened during the first phase of shortening (i.e. the hinterland). Thrusts formed during the first shortening phase may be reactivated during the later shortening phase. Spacing of the later phase structures is not as wide as expected, considering they across the pre-existing thickened wedge. Superposition of structures results in formation of type 1 fold interference pattern. Bedding is curved outwards both in the dome and basin structures. Folded layers are dipping and plunging outwards in a dome, while they are dipping and plunging inwards in a basin. In the areas between two adjacent domes or basins (i.e. where an anticline is superimposed by a syncline or a syncline is superimposed by an anticline), bedding is curved inwards, and the anticlines plunge inwards and the synclines outwards. The latter feature could be helpful to determine the age relationship for type 2 fold interference pattern. In tectonic regions where multiple phases of shortening have occurred, the orogenic-scale dome-and-basin and arrowhead-shaped interference patterns are commonly formed, as in the models. However, in some areas, the fold interference pattern might be modified by a later phase of thrusting. Similar to models results, superimposition of two and/or even more deformation phases may not be recorded by structures all over the tectonic area.

  • 4.
    Farzipour-Saein, Ali
    et al.
    Department of Geology, University of Isfahan, Iran.
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Koyi, Hemin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    The effect of basement step/topography on the geometry of the Zagros fold and thrust belt (SW Iran): an analogue modeling approach2013Inngår i: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 102, nr 8, s. 2117-2135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Systematic analogue models are run to study the variation in deformation across basement steps in the Zagros Fold-Thrust Belt. Our model results demonstrate that basement configuration/topography influences the sedimentation thickness and, hence, the kinematics and geometric evolution of the fold and thrust belt. The greater the difference in thickness between the adjacent cover units across a basement step, the sharper and clearer will be the offset the deformation front. Based on model results, we conclude that in a fold-thrust belt, where basement step/topography is covered by a layer of ductile salt acting as a decollement, the effect of the salt decollement on the evolution of the belt is far greater than the effect of thickness variation of the cover units.

  • 5.
    Ganas, Athanassios
    et al.
    National Observatory of Athens, Greece.
    Kapetanidis, Vasilis
    University of Athens, Greece.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Steffen, Holger
    Högskolan i Gävle.
    Lidberg, Martin
    Högskolan i Gävle.
    Deprez, Aline
    CNRS-UGA, France.
    Socquet, Anne
    CNRS-UGA, France.
    Walpersdorf, Andrea
    University of Grenoble, France.
    D'Agostino, Nicola
    INGV, France.
    Avallone, Antonio
    INGV, France.
    Legrand, Juliette
    ROB.
    Fernandes, Rui
    UBI-C4G.
    Nastase, Eduard Ilie
    National Institute for Earth Physics.
    Bos, Machiel
    UBI-C4G.
    Kenyeres, Ambrus
    BFKH Budapest, Bulgaria.
    Developments on the EPOS-IP pan-european strain rate product2018Inngår i: Book of Abstracts of the 36th General Assembly of the European Seismological Commission / [ed] D'Amico S., Galea P., Bozionelos G., Colica E., Farrugia D., Agius M.R., 2018, artikkel-id ESC2018-S2-749Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Strain rates are of great importance for Solid Earth Sciences. Within the EU Horizon 2020 project EPOS-IP WP10 (Global Navigation Satellite System - GNSS thematic core services) a series of products focused on strain rates derived from GNSS data is envisaged. In this contribution, we present preliminary results from 452 permanent European GNSS stations, operating until 2017 and processed at UGA-CNRS (Université Grenoble Alpes, Centre National de la Recherche Scientifique). We calculate the strain-rate field using two open-source algorithms recommended by EPOS-IP, namely the VISR (Velocity Interpolation for Strain Rate) algorithm (Shen et al., 2015) and STIB (Strain Tensor from Inversion of Baselines), developed by Masson et al., (2014) as well as the SSPX software suite (Cardozo and Allmendinger, 2009). The vertical velocity component is ignored in this stage and other sources of deformation (GIA, hydrological, anthropogenic et al.) are not considered in the interpretation. We compare the results derived from different methods and discuss the similarities and differences. Overall, our first results reproduce the gross features of tectonic deformation in both Italy and Greece, such as NE-SW extension across the Apennines and N-S extension in Central Greece. It is anticipated that the significant increase of GNSS data amount associated with the operational phase of EPOS project in the forthcoming years will be of great value to perform an unprecedented, reliable strain rate computation over the western Eurasian plate.

  • 6.
    Jivall, Lotti
    et al.
    Lantmäteriet.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Mast-based versus Pillar-based Networks for Coordinate Estimation of SWEREF points: – using the Bernese and GAMIT-GLOBK Software Packages2015Rapport (Annet vitenskapelig)
    Abstract [en]

    For about 20 years, the fundamental pillar stations in SWEPOS network (the Swedish Permanent GNSS network) have been used as the carrier of the Swedish national reference frame, SWEREF 99, and used as control points for several geodetic and geodynamic studies. Today, each pillar station has a close-by truss mast station, mostly in 10 meters distance. Switching from pillar-based network to mast-based network (with stations equipped with more modern receivers and calibrated antennas), as reference network,need careful analysis, for example, comparing solutions from these networks. In this study, we use both the Bernese GNSS Software (BSW) and GAMIT-GLOBK softwareand process the same data set with almost the same processing strategy and compare the results. Our solutions and their comparisons show that BSWhas slightly lower rate of resolved integer ambiguities for the mast-basednetwork compared to the pillar-basednetwork (3-4percentage pointsfor the selected 14 SWEREF points and 1-2percentage pointsfor all SWEREFpoints (50) processed in this study).For GAMIT-GLOBK, we don’tsee any significant difference in the rate of resolved integer ambiguities between the network types.Furthermore, the comparison of resulting coordinates between the two software, show avery good compliancefor the pillar-based network (on average at the 1 mm level for the horizontal components and 2 mm for the height component), but for the mast-based network there is 3-4 mm systematic difference in the height component.The good compliance between the GAMIT-GLOBK and BSW solutions for the pillar network,makes it possible to use results also from GAMIT-GLOBK for coordinate determination of SWEREF points. The systematic height difference between the two software solutions for the mast-based network,as well as slightly degraded quality measures mainlyfor BSW,indicate that there are some problems with the mast stations that need further investigation.

  • 7.
    Jivall, Lotti
    et al.
    Geodata Division, Lantmäteriet, Gävle, Sweden.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för datavetenskap och samhällsbyggnad, Samhällsbyggnad. Geodata Division, Lantmäteriet, Gävle, Sweden.
    Al Munaizel, Naim
    Geodata Division, Lantmäteriet, Gävle, Sweden.
    Lilje, Christina
    Geodata Division, Lantmäteriet, Gävle, Sweden.
    Kempe, Christina
    Geodata Division, Lantmäteriet, Gävle, Sweden.
    Maintenance of the National Realization of ETRS89 in Sweden : re-analysis of 20 years’ GPS data for SWEREF stations2019Inngår i: EUREF 2019 Symposium: Abstracts, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The national geodetic reference frame of Sweden called SWEREF 99, was adopted in 2000 by EUREF as the realisation of ETRS89 in Sweden and was officially introduced in 2001 as a national reference frame, that eventually in 2007 replaced the former reference frame. The SWEREF 99 reference frame is defined by an active approach through the 21 fundamental SWEPOS permanent GNSS stations, hence relying on positioning services such as the network real time kinematic (NRTK) and post processing service. The SWEREF 99 coordinates are assumed to be fixed in time and no temporal variations are expected. However, the stability of the stations and their coordinates can be altered due to equipment change or software as well as local movements at the reference stations.

    To be able to check all alterations mentioned above and having a backup national network of GNSS stations, approximately 300 passive so-called consolidation stations are used. The consolidation stations are a subset (main part) of the so-called SWEREF stations established from 1996 and onwards. All 300 stations are remeasured with static GNSS for 2x24 hours using choke ring antennas on a yearly basis with 50 stations each year. The original processing was done with the Bernese GNSS software (here called Bernese original) and the reprocessing was carried out with both the Bernese and the GAMIT-GLOBK software packages during 2017-2018.

    The resulting coordinates in SWEREF 99 from GAMIT and Bernese processing are equal at 1.2 mm level for horizontal and 4 mm for vertical components (1 sigma) when using the same models and processing strategy. The original processing, which partly is based on other models and parameters, differs slightly more (rms 2.4mm) for the north component. Our analysis both from Bernese and GAMIT shows that the standard uncertainties for a single SWEREF 99 determination (2x24 hrs) is 2 mm for the horizontal components and 6-7 mm in height. However, since some stations are slowly moving they have slightly increased the estimated uncertainties. It is interesting to note that the repeatability is on the same level also for the original processing, where we have differences in models and parameters used during the years. This indicates that the SWEREF-concept of determining SWEREF 99 coordinates has worked well on the mentioned uncertainty level.

    We performed trend analysis and statistical tests to investigate the stability of the estimated SWEREF 99 coordinates. The analysed station time series (minimum three observations) showed that about 14% of the stations had significant trends at the 95%-level. The possible explanation for those trends can be either local deformation and/or residuals of uplift model and/or computational effects such as lack of good or enough close-by stations for Helmert transformations from ITRF to SWEREF 99.

    The outcomes of the new processing and analysis reported here, are used to analyse the stability of SWEREF99 after two decades. The results have also been used to define the SWEREF 99 component in the fit of theSWEN17_RH2000 new geoid model to SWEREF 99 and RH 2000 (Swedish realisation of EVRS).

  • 8.
    Joudaki, Masoud
    et al.
    Univ Isfahan, Dept Geol, Esfahan, Iran.
    Farzipour-Saein, Ali
    Univ Isfahan, Dept Geol, Esfahan, Iran.
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Kinematics and surface fracture pattern of the Anaran basement fault zone in NW of the Zagros Fold-Thrust Belt2016Inngår i: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 105, nr 3, s. 869-883Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The preexisting north-south trending basement faults and their reactivation played an important role during the evolution of the Zagros fold-thrust belt. The Anaran basement fault in the Lurestan region, NW of the Zagros, has been considered as a N-S trending basement lineament, although its surface structural expression is still debated. In this study, we use satellite images and field observations to identify and analyze the fractures in the sedimentary cover above the Anaran basement fault. Fracture analysis demonstrates that approaching the Anaran basement fault, the fracture pattern changes. The fractures association with reactivation of the deep-seated preexisting Anaran basement fault can be categorized in 4 sets based on their directions. The mean direction for maximum compressional stress is different between the fault- and fold-related fractures within and around the ABF shear zone. We estimated an orientation of N30±5° for the fault-related fractures and N45±5° for the fold-related fracture sets outside of the ABF shear zone. This difference suggests that the fold-related and fault-related fracture sets have been formed in different two stages of deformation throughout the area. The axial traces of some folds, especially the Anaran anticline, demonstrate a right-lateral offset along the ABF, such that, in central part of the Anaran anticline, the fold axis of this anticline is changed from its original NW–SE trend to approximately north-south trend of the ABF.

  • 9. Kaviani, A.
    et al.
    Mahmoodabadi, M.
    Rümpker, G.
    Yamini-Fard, F.
    Tatar, M.
    Motavalli-Anbaran, J.
    Rahimzadeh, S.
    Moradi, A.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Complex pattern of seismic anisotropy beneath the Iranian plateau and Zagros2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We performed shear wave splitting analyses on core-refracted teleseismic shear waveforms from 150 broad-bandstations across the Iranian plateau and Zagros to investigate seismic anisotropy in the region. Seismic anisotropyis quantified by shear-wave splitting parameters, i.e. fast polarization direction and split delay time.Our measurements revealed a complex pattern of splitting parameters with variations in the trend and strength ofanisotropy across the tectonic boundaries. This complex pattern implies that a system of simple asthenosphericflow related to the absolute plate motion cannot alone explain our observations and that the lithosphere also hasa significant contribution in many parts. We compare our results to the surface deformation and velocity fieldsinferred from geodetic measurements to assess the role of the mantle in continental deformation. The rotationalpattern of the fast directions around the collision zone in Central Zagros may indicate the presence of a mantleflow around a continental keel beneath the Zagros. The agreement between the crustal and mantle deformationfield in Central Iran implies a vertically coherent deformation in this region, whereas the azimuthal variations insplitting parameters in the collision zone may suggest multi-layered anisotropy with different contributions fromthe crust and mantle.

  • 10.
    Khorrami, F.
    et al.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Vernant, P.
    Géosciences Montpellier- CNRS, Geosciences, Montpeliier, France.
    Masson, F.
    IPGS/EOST CNRS/University Strasbourg, Earth Sciences, Strasbourg, France.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för datavetenskap och samhällsbyggnad, Samhällsbyggnad. Lantmäteriet, Gävle, Sweden.
    Mousavi, Z.
    Institute for Advanced Studies in Basic Sciences IASBS.
    Nankali, H.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Saadat, S.A.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Walpersdorf, A.
    University Grenoble Alpes- CNRS, ISTerre, Grenoble, France.
    Hosseini, S.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Tavakoli, P.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Aghamohammadi, A.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    Alijanzade, M.
    National Cartographic Center, Geodesy and Land Surveying, Tehran, Iran (Islamic Republic of).
    An up-to-date block model and strain rate map of Iran using integrated campaign-mode and permanent GPS velocities2019Inngår i: 27th IUGG General Assembly: G06 - Posters - Monitoring and Understanding the Dynamic Earth With Geodetic Observations, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Iran accommodates a large part of the ongoing Arabia-Eurasia collision deformation. Because of such active tectonics, the country suffers from intensive seismicity and frequent destructive earthquakes in different locations.To study further the crustal deformation in Iran, we processed the data collected during 10 years (2006-2015) from the Iranian Permanent GNSS Network and combined them with previously published velocity solutions from GPS survey measurements during 1997–2013. We analysed this velocity field using a continuum approach to compute a new strain rate map for this region and we designed a block model based on the main geological, morphological, and seismic structures. Comparison between both approaches suggests similar results and allow us to present the first comprehensive first order fault slip rate estimates for the whole of Iran. Our results confirm most of the results from previous geodetic studies. Moreover, we also show a trade-off between the coupling ratio of the Iranian Makran subduction interface and the kinematic of the faults north of the Makran in the Jazmurian depression. Although too scarce to accurately estimate a coupling ratio, we show that coupling higher than 0.4 on the plate interface down to a depth of 25 km will induce extension on the E-W faults in the Jazmurian region. However, the sites close to the shoreline suggest a low coupling ratio, hence the coupling on this plate interface is probably more complicated than previously described and the Iranian Makran subduction interface mechanical behaviour might be similar to that on the Hellenic subduction zone.

  • 11. Khorrami, Fateme
    et al.
    Masson, Frederic
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Vernant, Philippe
    Saadat, Seyed Abdoreza
    Nankali, Hamidreza
    Hosseini, Sedigheh
    Aghamohamadi, Azadeh
    An up-to-date GPS velocity field of Iran2017Inngår i: Geophysical Research Abstracts, 2017, Vol. 19, artikkel-id EGU2017-7268Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study we present an up-to-date velocity field of Iran, including the largest number of data ever presentedon this region. It includes both a synthesis of all previously published campaign data (Raeesi et al., 2016) andall data from the Iranian Permanent GNSS Network (IPGN). The IPGN data cover some parts of Iran whichwere previously scarcely documented. These stations have been measured for 7 years. In total, more than 400instrumented sites are presented. From this velocity field, we calculated the strain rate.In this paper, we will show the contribution of this very dense velocity field to the detailed understanding of theactive tectonics of the various regions of Iran (Makran, Zagros, Alborz, ...).

  • 12.
    Khorrami, Fatemeh
    et al.
    National Cartographic Center, Tehran, Iran.
    Vernant, Philippe
    Géosciences Montpellier, CNRS/University Montpellier, Montpellier, France.
    Masson, Frederic
    IPGS/EOST CNRS/University Strasbourg, Strasbourg Cedex, France.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för datavetenskap och samhällsbyggnad, Samhällsbyggnad. Lantmäteriet, Gävle, Sweden.
    Mousavi, Zahra
    Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran.
    Nankali, Hamidreza
    National Cartographic Center, Tehran, Iran.
    Saadat, Seyed Abdolreza
    National Cartographic Center, Tehran, Iran.
    Walpersdorf, Andrea
    University Grenoble Alpes, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, France.
    Hosseini, Sedighe
    National Cartographic Center, Tehran, Iran.
    Tavakoli, Parastoo
    National Cartographic Center, Tehran, Iran.
    Aghamohammadi, Azade
    National Cartographic Center, Tehran, Iran.
    Alijanzade, Mahnaz
    National Cartographic Center, Tehran, Iran.
    An up-to-date crustal deformation map of Iran using integrated campaign-mode and permanent GPS velocities2019Inngår i: Geophysical Journal International, ISSN 0956-540X, E-ISSN 1365-246X, Vol. 217, nr 2, s. 832-843Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the most extensive and up-to-date unified GPS velocity field for Iran. We processed the data collected during 10 years (2006–2015) from the Iranian Permanent GNSS Network (IPGN) and combined them with previously published velocity solutions from GPS survey measurements during 1997–2013. We analysed this velocity field using a continuum approach to compute a new strain rate map for this region and we designed a block model based on the main geological, morphological, and seismic structures. Comparison between both approaches suggests similar results and allow us to present the first comprehensive first order fault slip rate estimates for the whole of Iran. Our results confirm most of the results from previous geodetic studies. But we also show a trade-off between the coupling ratio of the Iranian Makran subduction interface and the kinematic of the faults north of the Makran in the Jazmurian depression. Indeed, although too scarce to accurately estimate a coupling ratio, we show that coupling higher than 0.4 on the plate interface down to a depth of 25 km will induce extension on the E-W faults in the Jazmurian region. However, the sites close to the shoreline suggest a low coupling ratio, hence the coupling on this plate interface is probably more complicated than previously described and the Iranian Makran subduction interface mechanical behaviour might be similar to that on the Hellenic subduction zone.

  • 13.
    Koyi, Hemin
    et al.
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Hans Ramberg Tectonic Laboratory, Deptartment of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Hessami, Khaled
    International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran.
    Modelling role of basement block rotation and strike-slip faulting on structural pattern in cover units of fold-and-thrust belts2016Inngår i: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 153, nr 5-6, s. 827-844Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of scaled analogue models are used to study (de)coupling between basement and cover deformation. Rigid basal blocks were rotated about a vertical axis in a 'bookshelf'€™ fashion, which caused strike-slip faulting along the blocks and in the overlying cover units of loose sand. Three different combinations of cover–basement deformations are modelled: (i) cover shortening before basement fault movement; (ii) basement fault movement before cover shortening; and (iii) simultaneous cover shortening with basement fault movement. Results show that the effect of the basement faults depends on the timing of their reactivation. Pre- and syn-orogenic basement fault movements have a significant impact on the structural pattern of the cover units, whereas post-orogenic basement fault movement has less influence on the thickened hinterland of the overlying belt. The interaction of basement faulting and cover shortening results in the formation of rhombic structures. In models with pre- and syn-orogenic basement strike-slip faults, rhombic blocks develop as a result of shortening of the overlying cover during basement faulting. These rhombic blocks are similar in appearance to flower structures, but are different in kinematics, genesis and structural extent. We compare these model results to both the Zagros fold-and-thrust belt in southwestern Iran and the Alborz Mountains in northern Iran. Based on the model results, we conclude that the traces of basement faults in cover units rotate and migrate towards the foreland during regional shortening. As such, these traces do not necessarily indicate the actual location or orientation of the basement faults which created them.

  • 14.
    Lacombe, Olivier
    et al.
    Institut des Sciences de la Terre de Paris (iSTeP), Sorbonne Universités, Paris, France.
    Ruh, Jonas
    Institut des Sciences de la Terre de Paris (iSTeP), Sorbonne Universités, Paris, France; Instituto de Ciencias de la Tierra “Jaume Almera”, CSIC, Barcelona, Spain.
    Brown, Dennis
    Instituto de Ciencias de la Tierra “Jaume Almera”, CSIC, Barcelona, Spain.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Geodetic infrastructure Department, Lantmäteriet, Gävle, Sweden.
    Introduction: tectonic evolution and mechanics of basement-involved fold-and-thrust belts2016Inngår i: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 153, nr 5-6, s. 759-762Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Defining the structural style of fold-and-thrust belts is an important step for understanding the factors that control their long- and short-term dynamics, for comprehending seismic hazard associated with them, and for assessing their economic potential. While the thin-skinned model (no basement involvement) has long been the driving methodology for cross section construction and restoration of foreland fold-and-thrustbelts, a wealth of new geological and geophysical studies have shown that they are often thick-skinned, that is, basement-involved.

  • 15.
    Liu, Zhina
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Koyi, Hemin
    Uppsala universitet, Berggrundsgeologi.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Kinematics and internal deformation within 3-D granular slopes: insights from analogue mdoels and natural slopes2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study uses results of a series of analogue models, scanned data of natural landslides, and sections of natural failed slopes to investigate the kinematics and internal deformation during the failure of an unstable slope. The models simulate collapse of granular slopes by focusing on the spatial and temporal distribution of their internal structures. Model results show that the collapse of granular slopes resulted in different-generation extensional normal faults at the back of the slope, and contractional structures such as overturned folds, shealth folds and thrusts at the toe of the slope. The failure surfaces and the volume of the failure mass changed both spatially and temporally. Our model results show also that the nature of runout base has a significant influence on the kinematics and internal deformational structures. The runout distance increased with decreasing basal friction of a rigid runout base, and the topography at the slope toe was much gentler in the model with lower basal friction along the rigid runout base. The runout distance was shortest in the granular slope with deformable runout base. More extensional normal faults occurred in the model with low-friction runout base, whereas more shortening structures formed in the model with high-friction runout base. Similar tomodel results, our field observations indicate the presence of at least two generations of failure surfaces where the older ones are steeper.

  • 16.
    Liu, Zhina
    et al.
    Uppsala universitet, Institutionen för geovetenskaper.
    Koyi, Hemin
    Uppsala universitet, Institutionen för geovetenskaper.
    Nilfouroushan, Faramarz
    Uppsala universitet, Institutionen för geovetenskaper.
    Swantesson, Jan
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper, Avdelningen för hälsa och miljö.
    Reshetyuk, Yuriy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad/GIS-Institutet.
    Internal deformation within an unstable granular slope: insights from physical modeling2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The collapses of granular materials frequently occur in nature in the form of, for example, rock avalanches, debrisavalanches and debris flow. In previous studies of collapses of a granular material, most of the focus has been onthe effect of initial geometry and mechanical properties of the granular materials, the run-out distance, and thetopography of final deposit. In this study, results of analogue models and scanned natural failed slopes are usedto outline the mode of failure of an unstable slope. Model results and field observations are used to argue that agranular mass moves downslope in a wavy pattern resulting in its intensive deformation.In the models, we mainly investigated the internal deformation of collapses of granular slopes in terms of theirinternal structures and the spatial and temporal distribution of the latter. Model results showed that a displacedmass of the granular slope has the following two features: (1) Initial collapse resulted in a series of normal faults,where hanging-wall blocks were slightly deformed, like the slump-shear structures in nature; (2) With furthercollapse, a set of secondary structures, such as deformed/folded fault surfaces, faulted folds, displaced inclinedfolds, and overturned folds formed near the slope surface. The occurrence of these structures reflects the failureprocess of the granular mass in space and time. In addition, our model results show that the nature of basal frictionhas a significant influence on the geometry and kinematics of these structures at the slope toe. Model results showalso that the mass does not glide downslope along only one surface, but includes several gliding surfaces each ofwhich take part of the sliding. These gliding surfaces become steeper deeper in the sliding mass. Some of thesefeatures observed in the models are also detected in the field. Scanned failed slope surfaces show a wavy patternsimilar to that in the models, reflecting the presence of normal faults at the head of the slope and folding at theslope toe.

  • 17.
    Liu, Zhina
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Koyi, Hemin
    Uppsala universitet, Berggrundsgeologi.
    Swantesson, Jan
    Karlstad University.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Reshetyuk, Yuriy
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad/GIS-Institutet.
    Kinematics and 3-D internal deformation of granular slopes: analogue models and natural landslides2013Inngår i: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 53, s. 27-42Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study uses results from a series of analogue models, and field observations, scanned data and sections of natural landslides to investigate the kinematics and internal deformation during the failure of an unstable slope. The models simulate collapse of granular slopes and focus on the spatial and temporal distribution of their internal structures. Using a series of systematically designed models, we have studied the effect of friction and deformability of the runout base on internal deformation within a granular slope. The results of these different models show that the collapse of granular slopes resulted in different-generation extensional faults at the back of the slope, and contractional structures (overturned folds, sheath folds and thrusts) at the toe of the slope. The failure surfaces and the volume of the failure mass changed both spatially and temporally. Younger failure surfaces formed in the back of the older ones by incorporating additional new material from the head of the slope. Our model results also show that the nature of the runout base has a significant influence on the runout distance, topography and internal deformation of a granular slope. Model results are compared with natural landslides where local profiles were dug in order to decipher the internal structures of the failure mass. The natural cases show similar structural distribution at the head and toe of the failure mass. As in model results, our field observations indicate the presence of at least two generations of failure surfaces where the older ones are steeper.

  • 18.
    Mousavi, Z.
    et al.
    ISTerre, Université Joseph Fourier, Grenoble, France; National Cartographic Center, Geodetic Department, Tehran, Iran.
    Walpersdorf, A.
    ISTerre, Université Joseph Fourier, Grenoble, France.
    Walker, R.T.
    Department of Earth Sciences, University of Oxford, Oxford, UK.
    Tavakoli, F.
    National Cartographic Center, Geodetic Department, Tehran, Iran.
    Pathier, E.
    ISTerre, Université Joseph Fourier, Grenoble, France.
    Nankali, H.
    National Cartographic Center, Geodetic Department, Tehran, Iran.
    Nilfouroushan, Faramarz
    Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Djamour, Y.
    National Cartographic Center, Geodetic Department, Tehran, Iran.
    Global Positioning System constraints on the active tectonics of NE Iran and the South Caspian region2013Inngår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 377-378, s. 287-298Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a velocity field compiled from a network of 27 permanent and 20 campaign GPS stations  across NE Iran. This new GPS velocity field helps to investigate how Arabia-Eurasia collision deformation is accommodated at the northern boundary of the deforming zone. The present-day northward motion decreases eastward from 11 mm/yr at Tehran (~52°E) to 1.5 mm/yr at Mashhad  (~60°E). N-S shortening across the Kopeh Dagh, Binalud and Kuh-e-Surkh ranges sums to 4.5±0.5 mm/yr at longitude 59°E. The available GPS velocities allow us to describe the rigid-body rotation of the South Caspian about an Euler pole that is located further away than previously thought. We suggest that two new stations (MAVT and MAR2), which are sited far from the block boundaries, are most  likely to indicate the full motion of the South Caspian basin. These stations suggest that NW motion is accommodated by right-lateral slip on the Ashkabad fault (at a rate of up to 7 mm/yr) and by up to 4-6 mm/yr of summed left-lateral slip across the Shahroud left-lateral strike-slip system. Our new GPS results are important for assessing seismic hazard in NE Iran, which contains numerous large population centers and possesses an abundant historical earthquake record. Our results suggest that the fault zones along the eastern Alborz and western Kopeh Dagh may accommodate slip at much faster rates than previously thought. Fully assessing the role of these faults, and the hazard that they represent, requires independent verification of their slip-rates through additional GPS measurements and geological fieldwork.

  • 19.
    Nilfouroushan, Faramarz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Geodetic infrastructure Department, Lantmäteriet, Gävle, Sweden.
    Bagherbandi, Mohammad
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Gido, Nureldin
    Ground Subsidence And Groundwater Depletion In Iran: Integrated approach Using InSAR and Satellite Gravimetry2017Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Long-term monitoring of temporal gravity field and ground water level changes in Iran and its associated ground subsidence seen by geodetic methods are important for water source and hazard management.The high-rate (cm to dm/year) ground subsidence in Iran has been widely investigated by using different geodetic techniques such as precise leveling, GPS and interferometric synthetic aperture radar (InSAR). The previous individual SAR sensors (e.g. ERS, ENVISAT and ALOS) or multi-sensors approach have successfully shown localized subsidence in different parts of Iran. Now, thanks to freely available new SAR sensor Sentinel-1A data, we aim at investigate further the subsidence problem in this region.

    In this ongoing research, firstly, we use a series of Sentinel-1A SAR Images, acquired between 2014 to 2017 to generate subsidence-rate maps in different parts of the country. Then, we correlate the InSAR results with the monthly observations of the Gravity Recovery and Climate Experiment (GRACE) satellite mission in this region. The monthly GRACE data computed at CNES from 2002 to 2017 are used to compute the time series for total water storage changes. The Global Land Data Assimilation System( GLDAS) hydrological model (i.e. soil moisture, snow water equivalent and surface water) is used to estimate Groundwater changes from total water storage changes obtiaend from GRACE data.

    So far, we have generated a few interferograms, using Sentinel-1A data and SNAP software, which shows a few cm subsidence in western Tehran in last 2 years. We will try more Sentinel images for this area to better constrain the rate and extent of deformation and will continue InSAR processing for the rest of the country to localize the deformation zones and their rates. We will finally comapre the rates of subsidence obtained from InSAR and the rate of groundwater changes estimated from GRACE data.

  • 20.
    Nilfouroushan, Faramarz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Lantmäteriet.
    Jivall, Lotti
    Lantmäteriet.
    Al Munaizel, Naim
    Reprocessing and analysis of 20-years SWEREF stations GPS data using BERNESE and GAMIT software2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    SWEREF 99 has been used as the national geodetic reference frame in Sweden since 2007 and is adopted by EUREF as an ETRS89 realization. It is defined by an active approach through the 21 original SWEPOS stations, hence relying on positioning services like the network RTK service and the post processing service. All alterations of equipment and software as well as movements at the reference stations will in the end affect the coordinates. For checking the effect of all alterations mentioned above and having a backup network of GNSS stations, approximately 300 nationally distributed passive so-called consolidation points are used. The main part of the consolidation points consists of so-called SWEREF points established already with the beginning in the mid-1990s. All stations are remeasured with static GNSS for 2x24 hours using choke ring antennas in a 6 years base with 50 points each year. The original processing was done with the Bernese GNSS software and the reprocessing was carried out with both the Bernese GNSS software and the GAMIT software in 2017-18 covering so far 20 years of data. The station coordinates were first estimated in ITRF2008 and then transformed to SWEREF 99 using the new land uplift model NKG2016LU and close by reference stations. The outcome will be used to analyse the stability of SWEREF 99 after two decades and has been used to define the SWEREF 99 component in the fit of the SWEN17_RH2000 geoid model to SWEREF 99 and RH 2000. Our analysis show a very good agreement between repeated measurements. The mean RMS of the SWEREF 99 coordinates which have had 3-times measurements (every ~6 years) is 2 mm for the horizontal components and 5-6 mm for height. Moreover, we did trend analysis to investigate the stability of the stations and check if any systematic trend exists in the transformed SWEREF99 coordinates. In general, no significant trend was observed. However, at some stations trends were observed due to local ground movements.

  • 21.
    Nilfouroushan, Faramarz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Lantmäteriet, Geodetic infrastructure, Gävle, Sweden.
    Jivall, Lotti
    Lantmäteriet, Geodetic infrastructure, Gävle, Sweden.
    Al Munaizel, Naim
    Lantmäteriet, Geodetic infrastructure, Gävle, Sweden.
    Lilje, Christina
    Lantmäteriet, Geodetic infrastructure, Gävle, Sweden.
    Kempe, Christina
    Lantmäteriet, Geodetic infrastructure, Gävle, Sweden.
    Maintenance of the National Realisation of ETRS89 in Sweden: re-analysis of 20-years GPS data for SWEREF stations2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The national geodetic reference frame of Sweden called SWEREF 99, was adopted in 2000 by EUREF as therealization of ETRS89 in Sweden and was officially introduced in 2001 as a national reference frame, thateventually in 2007 replaced the former reference frame. The SWEREF 99 reference frame is defined by an activeapproach through the 21 fundamental SWEPOS permanent GNSS stations, hence relying on positioning servicessuch as the network real time kinematic (NRTK) and post processing service. The SWEREF 99 coordinates areassumed to be fixed in time and no temporal variations are expected. However, the stability of the stations andtheir coordinates can be altered due to equipment change or software as well as local movements at the referencestations.To be able to check all alterations mentioned above and having a backup national network of GNSS stations,approximately 300 passive so-called consolidation stations are used. The consolidation stations are a subset (mainpart) of the so-called SWEREF stations established from 1996 and onwards. All 300 stations are remeasured withstatic GNSS for 2x24 hours using choke ring antennas on a yearly basis with 50 stations each year. The originalprocessing was done with the Bernese GNSS software (here called Bernese original) and the reprocessing wascarried out with both the Bernese and the GAMIT-GLOBK software packages during 2017-2018.The resulting coordinates in SWEREF 99 from GAMIT and Bernese processing are equal at 1.2 mm level forhorizontal and 4 mm for vertical components (1 sigma) when using the same models and processing strategy.The original processing, which partly is based on other models and parameters, differs slightly more (rms 2.4mm) for the north component. Our analysis both from Bernese and GAMIT shows that the standard uncertaintiesfor a single SWEREF 99 determination (2x24 hrs) is 2 mm for the horizontal components and 6-7 mm inheight. However, since some stations are slowly moving they have slightly increased the estimated uncertainties.It is interesting to note that the repeatability is on the same level also for the original processing, where wehave differences in models and parameters used during the years. This indicates that the SWEREF-concept ofdetermining SWEREF99 coordinates has worked well on the mentioned uncertainty level.We performed trend analysis and statistical tests to investigate the stability of the estimated SWEREF 99coordinates. The analysed station time series (minimum three observations) showed that about 14% of the stationshad significant trends at the 95%-level. The possible explanation for those trends can be either local deformationand/or residuals of uplift model and/or computational effects such as lack of good or enough close-by stations forHelmert transformations from ITRF to SWEREF 99.The outcomes of the new processing and analysis reported here, are used to analyse the stability of SWEREF99 after two decades. The results have also been used to define the SWEREF 99 component in the fit of theSWEN17_RH2000 new geoid model to SWEREF 99 and RH 2000 (Swedish realization of EVRS).

  • 22.
    Nilfouroushan, Faramarz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Lantmäteriet.
    Jivall, Lotti
    Lantmäteriet.
    Lilje, Christina
    Lantmäteriet.
    Steffen, Holger
    Lantmäteriet.
    Lidberg, Martin
    Lantmäteriet.
    Johansson, Jan
    Chalmers University of Technology.
    Jarlemark, Per
    SP Technical Research Institute of Sweden.
    Evaluation of newly installed SWEPOS mast stations, individual vs. type PCV antenna models and comparison with pillar stations2016Inngår i: Geophysical Research Abstracts, Vienna: European Geosciences Union , 2016, Vol. 18, artikkel-id EGU2016-4265-1Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For about two decades, SWEPOS (the Swedish Permanent GNSS network) pillar stations have been used indifferent geodetic and geodynamic studies. To keep continuous measurements of these long lived pillar stationsand at the same time modernizing the SWEPOS network, it has been decided to install new truss mast stations,equipped with modern and individually calibrated antennas and radomes, capable of tracking all new GNSSsatellites. Installation of mast stations started in 2011. Today, each pillar station in the SWEPOS permanent GNSSnetwork has a close-by truss mast station, mostly in 10 meters distance with individual calibrated Leica chokering antenna and its attachment (LEIAR25.R3, LEIT). Due to their closeness to pillars, the modern mast stationsmay provide additional information for the analysis of ground movements in Sweden e.g. to distinguish betweentectonic and geodynamic processes (e.g. land uplift in Sweden).In this study, we have used two datasets from two different seasons for 21 pillars and 21 mast stations andformed different networks. The mast network has been processed using both IGS standard (type) and individuallycalibrated PCV (Phase Center Variation) models and therefore the effect of these two different PCV models onheight components has been investigated. In a combined network, we processed all 42 stations (21 pillars+21mast) to see how this multi-baseline network (861 baselines) combination differs from independent mast or pillarnetworks with much less baselines (210 baselines). For our analysis, we used the GAMIT-GLOBK softwareand compared different networks. Ambiguity resolutions, daily coordinate repeatability and differences betweenheight components in different solutions are presented. Moreover, the GAMIT and BERNESE solutions forcombined mast and pillar networks are compared.Our results suggest that the SWEPOS truss mast stations can reliably be used for crustal deformation studies.The comparison between pillar and mast stations shows similar time series for different horizontal and verticalcomponents and their Normalized rms (nrms) and weighted rms (wmrs) are almost equal.Comparison of standard and calibrated PCV models for mast stations show notable differences in height compo-nents and reach up to14 mm. These differences are antenna-dependent and are not systematic offsets. Therefore,whenever available, individual calibrated antenna models have to be used instead of standard (type) calibratedmodels.This study is part of the Swedish CLOSE III research project between Lantmäteriet, SP, and Chalmers Universityof Technology.

  • 23.
    Nilfouroushan, Faramarz
    et al.
    Uppsala universitet; Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap.
    Koyi, Hemin
    Uppsala Universitet.
    Swantesson, Jan O. H.
    Ekofilosofi.
    Talbot, Christoffer
    Uppsala Universitet.
    Effect of basal friction and volumetric strain in models of convergent settings measured by laser scanner2008Inngår i: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 30, s. 366-379Artikkel i tidsskrift (Fagfellevurdert)
  • 24.
    Nilfouroushan, Faramarz
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Pysklywec, Russell
    Cruden, A. R.
    Koyi, H.
    Uppsala universitet, Berggrundsgeologi.
    Role of Basement Faults on the Crustal Wedge Deformation of the Zagros fold-thrust belt, New Insights from 2-D Thermo-mechanical Numerical Models2010Konferansepaper (Fagfellevurdert)
  • 25.
    Nilfouroushan, Faramarz
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Pysklywec, Russell
    Cruden, Alexander
    Comparison of analogue and numerical models: Sensitivity of numerical "sandbox" models of fold-thrust belts to material cohesion2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Scaled analogue and numerical brittle-viscous shortening models are conducted and the effects of uncertainties of the cohesion of brittle materials in the numerical modeling results are investigated. We demonstrate that the numerical models are very sensitive to small cohesion changes; specifically the geometry and number of structures are variable, especially in models with two weak viscous layers.  The results of some of the scaled numerical models can be very similar to analogue models in the usual range of cohesion values (here 0-100 Pa) of brittle materials.

  • 26.
    Nilfouroushan, Faramarz
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Pysklywec, Russell
    Department of Geology, University of Toronto, Canada .
    Cruden, Alexander
    Department of Geology, University of Toronto, Canada M5S 3B1 c School of Geosciences, Monash University, Melbourne, Australia.
    Sensitivity analysis of numerical scaled models of fold-and-thrust belts to granular material cohesion variation and comparison with analogue experiments2012Inngår i: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 526-529, s. 196-206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Scaled analog and numerical brittle–viscous shortening models are employed to evaluate how fold–thrust structures evolve with changes in the cohesion of brittle materials, a rather poorly constrained physical parameter at this scale of experiment. The shortening models are characterized by various styles of shear zones and features resembling pop-up structures. The kinematics, geometry, and number of these structures are controlled by the viscous detachment layers in the models; the finite deformation of the model wedges is fundamentally different in model sets with one or two viscous layers. We demonstrate that the structural evolution of the numerical models is very sensitive to small changes in cohesion value. This is especially pronounced in the experiments that incorporate two weak viscous layers. The overall deformation of the numerical models is most similar to analog models when cohesion values are 70–80 Pa.

  • 27.
    Nilfouroushan, Faramarz
    et al.
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden; Department of Earth Sciences, University of Toronto, Toronto, ON, Canada.
    Pysklywec, Russell
    Department of Earth Sciences, University of Toronto, Toronto, ON, Canada.
    Cruden, Alexander
    School of Geosciences, Monash University Victoria, Melbourne, Australia.
    Koyi, Hemin
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Thermal-mechanical modeling of salt-based mountain belts with pre-existing basement faults: application to the Zagros fold and thrust belt, southwest Iran2013Inngår i: Tectonics, ISSN 0278-7407, E-ISSN 1944-9194, Vol. 32, nr 5, s. 1212-1226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two-dimensional thermal-mechanical models of thick-skinned, salt-based fold and thrust belts,  such as the Zagros, SW Iran, are used to address: 1) the degree of deformation and decoupling between cover and basement rocks due to the presence of a weak salt detachment; 2) the reactivation potential of pre-existing basement normal faults due to brittle or ductile behavior of the lower crust (as related to cold or hot geothermal gradients); and 3) variations in deformation style and strain distribution. The geometry and kinematics of the orogenic wedge and the activity of pre-existing basement faults are strongly influenced by the geothermal gradient (defined by the Moho temperature, MT) and basement rheology. We infer that the MT plays a major role in how the lower and upper crust transfer deformation towards the foreland. In relatively hot geotherm models (MT = 600°C at 36 km depth), the lowermost basement deforms in a ductile fashion while the uppermost basement underlying the sedimentary cover deforms by folding, thrusting, and displacements along pre-existing basement faults. In these models, cover units above the salt detachment occur within a less deformed, wide plateau in the hinterland. In relatively cold geotherm models (MT = 400°C at 36 km depth), deformation is mainly restricted to basement imbricate thrusts that form within the orogenic hinterland. Detachment folding, thrusting and gravity gliding occur within cover sediments above uplifted basement blocks. Gravity gliding contributes to a larger amount of shortening in the cover compared to the basement.

  • 28.
    Nilfouroushan, Faramarz
    et al.
    Uppsala universitet, Berggrundsgeologi.
    Talbot, C. J.Uppsala universitet, Berggrundsgeologi.Hodacs, PeterUppsala universitet, Berggrundsgeologi.Koyi, HeminUppsala universitet, Berggrundsgeologi.Sjöberg, LarsRoyal Institute of Technology (KTH), Stockholm, Sweden.
    Geodetic horizontal velocity and strain rate fields around Lake Vänern (SW Sweden) derived from GPS measurements between 1997 and 20112012Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    In 1989, the Värmland GPS network consisting of 8 stations spaced an average of 60 km apart was setup to monitor the ongoing deformation in and around Lake Vänern due to tectonic and mainly Glacial Isostatic Adjustment (GIA) processes in Fennoscandia. This network covers an area of about 10000 km2, straddles the Protogine and the Mylonite zones and includes one of the most active seismic zones of Sweden. We use GAMIT-GLOBK software to process the past GPS data, collected in October 1997, the only campaign that was measured with choke ring antenna, and the new GPS measurements in October 2010 and 2011 to estimate station velocities. We also integrate our local network with the SWEPOS (Swedish Permanent GPS network) and IGS (International GNSS Service) stations to better constrain the velocity fields in ITRF2008 and Eurasia-fixed reference frames. Since the rates of horizontal movements are very slow (less than 1 mm/year), our measurements in longer time spans (at least in 13 years, between 1997 to 2010, 2011 and planned 2012) better resolve the tectonic signal from the noise. Preliminary results obtained from campaign-mode measurements in 1997, 2010 and 2011 agree well with those reported in the latest study by Lidberg et al. (2010) who used the data from permanent GPS stations of the BIFROST (Baseline Inferences for Fennoscandian Rebound Observations Sea Level and Tectonics) project. Strain-rate analysis resulting from the obtained velocities illustrates the overall extensional component trending NW-SE with local variations. Adding more campaigns in 2012 and 2013 will surely increase the reliability of our analysis. The velocity field obtained from this research will add more details to the tectonic picture generated by BIFROST. The results are also relevant to GIA modeling, geodetic vs. seismic strain accumulation, waste isolation and seismic hazards.

  • 29. Pease, Victoria
    et al.
    Koyi, Hemin
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Development of the Amerasia Basin: Insights from analogue modeling2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The tectonic development of the Amerasia Basin and its sub‐domains (the Canada Basin, the Makarov‐Povodnikov basins, the Alpha‐Mendeleev Ridges, and the Chukchi Plateau) has long been debated.  Recent studies confirm the conjugate relationship between the Alaskan and Canadian Arctic margins, in which counterclockwise rotation of Arctic Alaska from Arctic Canada resulted in the opening of the Canada Basin; although the northward extent of this spreading is debated, the tectonic development of the Canada Basin is ‘broadly’ understood.  The precise timing and the role of the Chukchi Plateau is also problematic.  In a series of two‐plate analogue models with properties homologous of homogeneous continental crust, we were able to model the development of the Amerasia basin and its sub‐domains (those not related to the HALIP).  In all models, a triangular (ocean) basin forms between the two ‘diverging’ plates, however, depending on the mode of opening and initial plate configuration transpressive, transtensive, and ‘pure’ strike‐slip structures are generated and account for the following first order observations: i) transcurrent margins of opposite motion, ii) curvature in the fossil ridge, and ii) asymmetry of the basin.  In addition, extension and clockwise rotation of the Chukchi Plateau (without compression) is achieved as part of the upper‐plate of a detachment system in which lower‐plate motion exceeds upper‐plate motion. Our results elucidate the development of sea‐floor spreading in the Amerasia Basin and are consistent with a rotational opening scenario.

  • 30. Pease, Victoria
    et al.
    Koyi, Hemin
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Development of the Amerasia Basin: Where are we now?2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This contribution reviews our current understanding of the tectonic development of the Amerasia Basin and presents new analogue modelling results relating to its formation. The Amerasia Basin is separated into the Canada Basin and the Makarov-Povodnikov basins by the Alpha-Mendeleev Ridges. Published data supports a conjugate relationship between the Alaskan and Canadian Arctic margins, in which counterclockwise rotation of Arctic Alaska from Arctic Canada resulted in the opening of the Canada Basin. Thus the tectonic development of the Canada Basin is ‘broadly’ understood, although its precise timing and the role of the Chukchi Plateau remain disputed. This leaves the Amerasia Basin and we identify two significant barriers to understanding its tectonic development: i) The northward extent of the Canada Basin fossil spreading ridge, and ii) the role of LIP magmatism. In assessing the former, we constructed a series of two-plate analogue models with properties homologous of homogeneous continental crust and simulated extension between the plates around a common rotation axis. In all models, a triangular (ocean) basin forms between the two ‘diverging’ plates, however, depending on the mode of opening and initial plate configuration transpressive, transtensive, and ‘pure’ strike-slip structures can be generated. Plates with a fixed pole of rotation that move at the same rate produce a basin that widens away from the pole along a straight ridge, whereas models with a migrating pole of rotation produce a bend in the spreading ridge and this may explain the curved ridge observed in the Canada Basin. Both models produce strike-slip faults of reversed polarity in the region opposite the pole. If the spreading ridge extended to the Lomonosov Ridge (LR), a strike-slip fault boundary is generated ± associated transtensive/transpressive features. Two plates with different spreading rates generate asymmetric basins, which is also a component of the Amerasia Basin. These results elucidate the consequences of sea-floor spreading in the Amerasia Basin and constrain opening scenarios.

  • 31.
    Pease, Victoria
    et al.
    Stockholm University, Stockholm, Sweden.
    Koyi, Hemin
    Uppsala University, Uppsala, Sweden.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Development of the Amerasia Basin: Where are we now?2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This contribution reviews our current understanding of the tectonic development of the Amerasia Basin and presents new analogue modelling results relating to its formation. The Amerasia Basin is separated into the Canada Basin and the Makarov-Povodnikov basins by the Alpha-Mendeleev Ridges. Published data supports a conjugate relationship between the Alaskan and Canadian Arctic margins, in which counterclockwise rotation of Arctic Alaska from Arctic Canada resulted in the opening of the Canada Basin. Thus the tectonic development of the Canada Basin is ‘broadly’ understood, although its precise timing and the role of the Chukchi Plateau remain disputed. This leaves the Amerasia Basin and we identify two significant barriers to understanding its tectonic development: i) The northward extent of the Canada Basin fossil spreading ridge, and ii) the role of LIP magmatism. In assessing the former, we constructed a series of two-plate analogue models with properties homologous of homogeneous continental crust and simulated extension between the plates around a common rotation axis. In all models, a triangular (ocean) basin forms between the two ‘diverging’ plates, however, depending on the mode of opening and initial plate configuration transpressive, transtensive, and ‘pure’ strike-slip structures can be generated. Plates with a fixed pole of rotation that move at the same rate produce a basin that widens away from the pole along a straight ridge, whereas models with a migrating pole of rotation produce a bend in the spreading ridge and this may explain the curved ridge observed in the Canada Basin. Both models produce strike-slip faults of reversed polarity in the region opposite the pole. If the spreading ridge extended to the Lomonosov Ridge (LR), a strike-slip fault boundary is generated ± associated transtensive/transpressive features. Two plates with different spreading rates generate asymmetric basins, which is also a component of the Amerasia Basin. These results elucidate the consequences of sea-floor spreading in the Amerasia Basin and constrain opening scenarios.

  • 32.
    Raeesi, Mohammad
    et al.
    Bergen, Norway.
    Zarifi, Zoya
    Department of Earth Sciences, University of Western Ontario, London, Canada.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Lantmäteriet, Gävle, Sweden.
    Boroujeni, Samar
    Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Tiampo, Kristy
    CIRES; Department of Geological Sciences, University of Colorado at Boulder, Boulder, CO, USA.
    Quantitative Analysis of Seismicity in Iran2017Inngår i: Pure and Applied Geophysics, ISSN 0033-4553, E-ISSN 1420-9136, Vol. 174, nr 3, s. 793-833Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We use historical and recent major earthquakes and GPS geodetic data to compute seismic strain rate, geodetic slip deficit, static stress drop, the parameters of the magnitude–frequency distribution and geodetic strain rate in the Iranian Plateau to identify seismically mature fault segments and regions. Our analysis suggests that 11 fault segments are in the mature stage of the earthquake cycle, with the possibility of generating major earthquakes. These faults primarily are located in the north and the east of Iran. Four seismically mature regions in southern Iran with the potential for damaging strong earthquakes are also identified. We also delineate four additional fault segments in Iran that can generate major earthquakes without robust clues to their maturity.The most important fault segment in this study is the strike-slip system near the capital city of Tehran, with the potential to cause more than one million fatalities.

  • 33.
    Rashidi, Ahmad
    et al.
    International Institute of Earthquake Engineering and Seismology, Tehran, Iran.
    Khatib, Mohamad Mahdi
    Department of Geology, University of Birjand, Birjand, Iran.
    Nilfouroushan, Faramarz
    Lantmäteriet, Gävle, Sweden.
    Derakhshani, Reza
    Department of Geology, Shahid Bahonar University of Kerman, Kerman, Iran; Department of Earth Sciences, Utrecht University, Utrecht, the Netherlands.
    Mousavi, Seyed Morteza
    Department of Geology, University of Birjand, Birjand, Iran.
    Kianimehr, Hossein
    International Institute of Earthquake Engineering and Seismology, Tehran, Iran; Iranian Seismological Center, Institute of Geophysics, University of Tehran, Tehran, Iran.
    Djamour, Yahya
    Geomatics College, National Cartographic Center of I.R., Tehran, Iran.
    Strain rate and stress fields in the West and South Lut block, Iran: Insights from the inversion of focal mechanism and geodetic data2019Inngår i: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 766, s. 94-114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The active tectonic deformation and hazardous earthquakes in the south and west of the Lut block have been investigated for a long time. In this study, we compute the geodetic and seismic strain rates using focal mechanism data from the Harvard CMT catalogue and various other sources including the published GPS velocities. Moreover, we also perform Focal Mechanism Stress Inversion (FMSI) to deduce a stress model for the region. Our study shows an expected correlation between the stress orientations, seismic and geodetic strain rates. Our results show that the south and west of the Lut block is generally exposed as a compressional strike-slip tectonic regime. The tectonic convergence in this area is taken up not only by motions along and across the faults but also by the rotation of those blocks which bounded by these faults. The maximum amount of rotation rate is observed where there are the main right lateral strike slip fault systems such as Sabzevaran, Gowk, Nayband, Bam, Kuhbanan, and Kahurak. The orientation of the mean stress direction, obtained from the FMSI results in the west and south of the Lut block, is approximated ~N19 E. In this area, faults are almost oblique relative to the tectonic motion direction. Moreover, there are right-lateral and left-lateral shears, in addition to the dip movements in different parts of the south and west of the Lut block. Our analyses show three main categories of the stress regimes including strike-slip faulting (43.2%), thrust faulting (38.6%), and unknown or oblique faulting (18.2%).

    We also calculated seismic and geodetic moment rates for this area, which indicate the seismic moment rate is relatively high between Bam and Shahdad where there are some segments of the Gowk fault.

  • 34. Schreurs, G.
    et al.
    Buiter, S.
    Burberry, C.
    Callot, Jean-Paul
    Cavozzi, C.
    Cerca, M.
    Cristallini, E.
    Cruden, A.
    Chen, J. H.
    Cruz, L.
    Daniel, J.M.
    Garcia, V. H.
    Gomes, C.
    Grall, C.
    Guzmán, C.
    Nur Hidayah, T.
    Hilley, G.
    Lu, C.Y.
    Klinkmüller, M.
    Koyi, H.
    Uppsala universitet, Berggrundsgeologi.
    Macauley, J.
    Maillot, B.
    Meriaux, C.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Pan, C. C.
    Pillot, D.
    Portillo, R.
    Rosenau, M.
    Schellart, W. P.
    Schlische, R.
    Take, A.
    Vendeville, B.
    Vettori, M.
    Vergnaud, M.
    Wang, S. H.
    Withjack, M.
    Yagupsky, D.
    Yamada, Y.
    Quantitative comparisons of analogue models of brittle wedge2010Konferansepaper (Fagfellevurdert)
  • 35.
    Schreurs, Guido
    et al.
    Institute of Geological Sciences, University of Bern, Bern, Switzerland.
    Buiter, Susanne J. H.
    Geodynamics Team, Geological Survey of Norway, Trondheim, Norway; The Centre for Earth Evolution and Dynamics, University of Oslo, Blindern, Oslo, Norway.
    Boutelier, Jennifer
    Department of Geology, University of Toronto, Toronto, Ontario, Canada.
    Burberry, Caroline
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Callot, Jean-Paul
    IFP Energies Nouvelles, Rueil Malmaison, Cedex, France.
    Cavozzi, Cristian
    NEXT – Natural and Experimental Tectonics Research Group, Department of Physics and Earth Sciences, “Macedonio Melloni”, University of Parma, Parma, Italy .
    Cerca, Mariano
    Universidad Nacional Autonoma de Mexico, Centro de Geociencias, Juriquilla, Queretaro, Mexico.
    Chen, Jian-Hong
    Department of Geosciences, National Taiwan University, Taipei, Taiwan.
    Cristallini, Ernesto
    Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
    Cruden, Alexander R.
    Department of Geology, University of Toronto, Toronto, Ontario, Canada.
    Cruz, Leonardo
    Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, USA.
    Daniel, Jean-Marc
    IFP Energies Nouvelles, Rueil Malmaison, Cedex, France.
    Da Poian, Gabriela
    Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
    Garcia, Victor H.
    Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
    Gomes, Caroline J. S.
    Departamento de Geologia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
    Grall, Céline
    IFP Energies Nouvelles, Rueil Malmaison, Cedex, France.
    Guillot, Yannick
    Université Lille-Nord de France, Laboratoire Géosystèmes, Villeneuve d’Ascq, Cedex, France.
    Guzmán, Cecilia
    Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
    Nur Hidayah, Triyani
    Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA.
    Hilley, George
    Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, USA.
    Klinkmüller, Matthias
    Institute of Geological Sciences, University of Bern, Bern, Switzerland.
    Koyi, Hemin A.
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Lu, Chia-Yu
    Department of Geosciences, National Taiwan University, Taipei, Taiwan.
    Maillot, Bertrand
    Laboratoire Géosciences et Environnement Cergy, Université de Cergy-Pontoise, Neuville-sur-Oise, Cergy-Pontoise, Cedex, France.
    Meriaux, Catherine
    School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria, Australia.
    Nilfouroushan, Faramarz
    Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Pan, Chang-Chih
    Department of Geosciences, National Taiwan University, Taipei, Taiwan.
    Pillot, Daniel
    IFP Energies Nouvelles, Rueil Malmaison, Cedex, France.
    Portillo, Rodrigo
    Universidad Nacional Autonoma de Mexico, Centro de Geociencias, Juriquilla, Queretaro, Mexico.
    Rosenau, Matthias
    Helmholtz-Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany.
    Schellart, Wouter P.
    School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria, Australia.
    Schlische, Roy W.
    Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA.
    Take, Andy
    Department of Civil Engineering, Queen's University, Kingston, Ontario, Canada.
    Vendeville, Bruno
    Université Lille, Laboratoire d’Océanologie et de Géosciences, Lille, France.
    Vergnaud, Marine
    IFP Energies Nouvelles, Rueil Malmaison, Cedex, France.
    Vettori, Matteo
    NEXT – Natural and Experimental Tectonics Research Group, Department of Physics and Earth Sciences “Macedonio Melloni”, University of Parma, Parma, Italy.
    Wang, Shih-Hsien
    Department of Geosciences, National Taiwan University, Taipei, Taiwan.
    Withjack, Martha O.
    Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA.
    Yagupsky, Daniel
    Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
    Yamada, Yasuhiro
    Department of Civil and Earth Resources Engineering, Kyoto University, Kyoto, Japan.
    Benchmarking analogue models of brittle thrust wedges2016Inngår i: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 92, s. 116-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We performed a quantitative comparison of brittle thrust wedge experiments to evaluate the variabilityamong analogue models and to appraise the reproducibility and limits of model interpretation. Fifteenanalogue modeling laboratories participated in this benchmark initiative. Each laboratory received ashipment of the same type of quartz and corundum sand and all laboratories adhered to a stringentmodel building protocol and used the same type of foil to cover base and sidewalls of the sandbox. Sievestructure, sifting height,filling rate, and details on off-scraping of excess sand followed prescribedprocedures.Our analogue benchmark shows that even for simple plane-strain experiments with prescribedstringent model construction techniques, quantitative model results show variability, most notably forsurface slope, thrust spacing and number of forward and backthrusts. One of the sources of the variabilityin model results is related to slight variations in how sand is deposited in the sandbox. Small changes insifting height, sifting rate, and scraping will result in slightly heterogeneous material bulk densities,which will affect the mechanical properties of the sand, and will result in lateral and vertical differencesin peak and boundary friction angles, as well as cohesion values once the model is constructed. Initialvariations in basal friction are inferred to play the most important role in causing model variability.Our comparison shows that the human factor plays a decisive role, and even when one modeler re-peats the same experiment, quantitative model results still show variability. Our observations highlightthe limits of up-scaling quantitative analogue model results to nature or for making comparisons withnumerical models. The frictional behavior of sand is highly sensitive to small variations in material stateor experimental set-up, and hence, it will remain difficult to scale quantitative results such as number ofthrusts, thrust spacing, and pop-up width from model to nature.

  • 36. Shahpasandzadeh, M.
    et al.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Koyi, H.
    Uppsala universitet, Berggrundsgeologi.
    Kinematics of structures and active tectonics of an active orogenic belt, Alborz Mountains, northern Iran: New insights from scaled analogue modeling2010Konferansepaper (Fagfellevurdert)
  • 37.
    Shahpasand-zadeh, Majid
    et al.
    Department of Earth Sciences, Kerman Graduate University of Technology, Kerman, Iran.
    Koyi, Hemin
    Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    The significance of switch in convergence direction in the Alborz Mountains, northern Iran: insights from scaled analogue modelling2017Inngår i: Interpretation, ISSN 2324-8858, E-ISSN 2324-8866, Vol. 5, nr 1, s. SD81-SD98Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The switch in direction of convergence between Central Iran and the Eurasian plate isbelieved to have a significant impact on the structural style in the Alborz Mountains, in northof Iran. To understand the deformation pattern and investigate the influence of the SouthCaspian Basin (SCB) kinematics since the middle Miocene on the structural styles and activetectonics of the Alborz Mountains, a series of scaled analogue models were prepared, wherepassively layered loose sand simulating the sedimentary units were subjected toorthogonal and subsequently oblique shortening by a rigid indenter. Model resultsshow that during the shortening an arcuate-shape foreland-vergent imbricate stack forms infront of the indenter. The orthogonal shortening is characterized by a prevailing right-lateraland left-lateral oblique-slip motion in the east and west of the model, respectively. This shiftin kinematics contradicts the proposed pre-neotectonic (orthogonal) model of the Alborz.However, during oblique shortening, model results show that deformation is mainlyaccommodated by left-lateral transpression within the sand wedge and by its internaldeformation. Oblique shortening is consistently accommodated by continued left-lateralmotion on the WNW-trending oblique thrusts, whereas the east-west trending thrusts and thepre-existing ENE-trending right-lateral oblique thrusts reactivate as left-lateral oblique faults.Precise monitoring of the model surface also illustrates partitioning of shortening into theforeland-vergent left-lateral thrusting in the south and hinterland-vergent back thrusting in thenorth. These model results are generally consistent with field observations and GPS data ofstructure and kinematics of the Alborz Mountains.

  • 38. Sorbi, Mohammad Reza
    et al.
    Nilfouroushan, Faramarz
    Uppsala universitet, Berggrundsgeologi.
    Zamani, Ahmad
    Seismicity patterns associated with the September 10th, 2008 Qeshm earthquake, South Iran2012Inngår i: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 101, nr 8, s. 2215-2223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The b value of the Gutenberg-Richter relation and the standard deviate, Z, were calculated to investigate the temporal and spatial variations in seismicity patterns associated with the September 10th, 2008 (Mw=6.1) Qeshm earthquake. The temporal variations of b value illustrate a distinct dramatic drop preceding the Qeshm earthquake and the spatial changes in b value highlight a zone with an abnormally low b value around the epicenter of this event. The Cumulative number and Z value as a function of time shows a precursory seismic quiescence preceding the 2008 Qeshm earthquake that observed for one year in a circle with R=50 km around its epicenter. The spatial distribution map of the standard deviate, Z, also exhibits an obvious precursory seismic quiescence region before the 2008 Qeshm event around the epicenter of this event. Interestingly, the precursory seismic quiescence region is approximately consistent with low b value anomaly region and both have E-W to NE-SW trend. These two precursory anomalies took place in relatively large regions, which were possibly relevant to the preparation zone of the 2008 Qeshm event.

  • 39. Steffen, Holger
    et al.
    Ganas, Athanassios
    Kapetanidis, Vasilis
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Lidberg, Martin
    Lantmäteriet, Gävle, Sweden.
    WP10 Members, EPOS
    The EPOS GNSS strain rate product (Y2018) – status and open questions2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Geodetic strain rate as derived from Global Navigation Satellite System (GNSS) station velocities is the rate of deformation in the crust (distance change combined with rotations and elevation changes) within a corresponding time. GNSS-derived strain rates are of great importance for Solid Earth Sciences, for example, in seismotectonic and geodynamic studies for comparison to stress fields and rates of earthquake occurrence or interpretation of plate motion characteristics, i.e. in plate boundary areas. Within the EU Horizon 2020 project EPOS-IP (European Plate Observing System-Implementation Phase) WP10 (GNSS thematic core services) a series of GNSS-derived strain rates products for Europe is envisaged. The project is currently in the last steps of the Implementation Phase before reaching the Operational Phase in 2020. We will present the status of the planned strain-rate product. This includes an overview of anticipated data input and output, methods for strain rate calculation and suggestions for the strain rate data portal. We will also raise a few open questions that we would like to discuss and for which we anticipate fruitful feedback from the EUREF community.

  • 40. Tavakoli, F.
    et al.
    Walpersdorf, A.
    Authemayou, C.
    Nankali, H. R.
    Hatzfeld, D.
    Tatar, M.
    Djamour, Y.
    Nilfouroushan, Faramarz
    solid earth Geology.
    Cotte, N.
    Distribution of the right-lateral strike-slip motion from the Main Recent Fault to the Kazerun Fault System (Zagros, Iran): Evidence from present-day GPS velocities2008Inngår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 275, s. 342-375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    GPS measurements across the Kazerun Fault System in the Zagros mountain belt provide first instantaneous velocities on the different segments. These results are closely consistent with the geological fault slip rates (over 150 ka), implying stable velocities over a longer period. The present-day strike–slip motion is distributed from the Main Recent Fault to the N-trending Kazerun Fault System along a preferential en-echelon fault zone included in a more distributed fan-shape fault pattern. The Hormuz salt decoupling layer cannot be the only cause of a sedimentary spreading because seismicity attests these faults are rooted in the basement. The Dena fault (3.7 mm/yr) transfers the MRF fault slip mainly to the Kazerun (3.6 mm/yr) and slightly to the High Zagros and Sabz Pushan faults (1.5 mm/yr), and the Kazerun fault further to the Kareh Bas fault (3.4 mm/yr). Total geological horizontal offsets associated with GPS slip rates help inferring precise fault slip onset ages. The successive onsets deduced by this approach imply that the right-lateral strike-slip activity of the MRF has propagated in time southeastward to the Dena segment, and then to the Kazerun segment and to the Kareh Bas fault.

  • 41. Taymaz, Tuncay
    et al.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Yolsal-Çevikbilen, Seda
    Eken, Tuna
    Co-seismic Crustal Deformation of the 12 November 2017 Mw 7.4Sar-Pol-Zahab (Iran) Earthquake: integration of analysis based on DInSAR and seismological observations2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The November 12, 2017 Mw 7.4 earthquake that trembled near the border region between Halabjah (Iraq) andSarpol-e Zahab (Iran) is the largest ever-recorded earthquake in the Zagros Mountains since 1900. The epicenterlocation of the event suggests that the NNW trending Mountain Front Fault (MFF) has been responsible for theearthquake though it was not associated with surface faulting. Analysis of teleseismic P- and SH- body-waveformsdata indicate a well-constrained rupture propagated along the dip direction of the fault plane with an effectiverupture area of 80km long, 70km wide and focal depth of 192 km ENE dipping low-angle thrust faulting with asmall strike-slip component that produced little uplift in the region (Strike: 358o; Dip: 16o, Rake: 149o and SeismicMoment (Mo): 1.828x1020 N.m. with maximum displacement (Dmax) of 6.9m at hypocenter, and rupture velocity(Vr) of 3.2 km/s). The source rupture duration is about 45s, but the main moment release is observed in the first10s. Focal mechanism solution of the event indicates a NNW trending plane dipping 16 degrees ENE. This isin agreement with the dip direction of the MFF and the distribution of aftershocks covering an area some 50-70km wide. We explore its details in astonishment, if it is proved, that the Zagros Mountain Front fault (MFF) wasresponsible then it might have become curved at depth (?)To measure the co-seismic crustal deformation around the epicenter, we processed the ascending and descendingSentinel-1 SAR images, collected before and after the earthquake, by SNAP software and generated the interferogramsof surface deformation. The Differential InSAR (DInSAR) results show an upward and downward displacementsof 90 cm and 30 cm around the epicenter respectively. Furthermore, we investigate the differencebetween strike derived from seismological and that inferred from DInSAR satellite observations, and its possiblecauses.We do not have “best” or “right” rupture model yet, but just models satisfying for specific data sets. The aftermathof earthquakes like the 2017 Halabjah (Irak)-Sarpol-e Zahab (˙Iran) provides excellent opportunity to evaluate ourunderstanding of earthquakes and their hazards in the earthquake prone regions.

  • 42. Vajedian, Sanaz
    et al.
    Motagh, Mahdi
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Response to Sowter, A.; Cigna, F. On the Use of the ISBAS Acronym in InSAR Applications. Comment on Vajedian, S.; Motagh, M.; Nilfouroushan, F. StaMPS Improvement for Deformation Analysis in Mountainous Regions: Implications for the Damavand Volcano and Mosha Fault in Alborz. Remote Sens. 2015, 7, 8323–83472015Inngår i: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 7, nr 9, s. 11324-11325Artikkel i tidsskrift (Fagfellevurdert)
  • 43.
    Vajedian, Sanaz
    et al.
    Department of Surveying and Geomatics Engineering, University of Tehran, Tehran, Iran.
    Motagh, Mahdi
    GFZ German Research Center for Geosciences, Potsdam, Germany; Department of Surveying and Geomatics Engineering, University of Tehran, Tehran, Iran.
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    STaMPS improvement for deformation analysis in mountainous regions: Implications for Damavand volcano and Mosha fault in Alborz2015Inngår i: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 7, nr 7, s. 8323-8347Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interferometric Synthetic Aperture Radar (InSAR) capability to detect slow deformation over terrain areas is limited by temporal decorrelation, geometric decorrelation and atmospheric artefacts. Multitemporal InSAR methods such as Persistent Scatterer (PS-InSAR) and Small Baseline Subset (SBAS) have been developed to deal with various aspects of decorrelation and atmospheric problems affecting InSAR observations. Nevertheless, the applicability of both PS-InSAR and SBAS in mountainous regions is still challenging. Correct phase unwrapping in both methods is hampered due to geometric decorrelation in particular when using C-band SAR data for deformation analysis. In this paper, we build upon the SBAS method implemented in StaMPS software and improved the technique, here called ISBAS, to assess tectonic and volcanic deformation in the center of the Alborz Mountains in Iran using both Envisat and ALOS SAR data. We modify several aspects within the chain of the processing including: filtering prior to phase unwrapping, topographic correction within three-dimensional phase unwrapping, reducing the atmospheric noise with the help of additional GPS data, and removing the ramp caused by ionosphere turbulence and/or orbit errors to better estimate crustal deformation in this tectonically active region. Topographic correction is done within the three-dimensional unwrapping in order to improve the phase unwrapping process, which is in contrast to previous methods in which DEM error is estimated before/after phase unwrapping. Our experiments show that our improved SBAS approach is able to better characterize the tectonic and volcanic deformation in the center of the Alborz region than the classical SBAS. In particular, Damavand volcano shows an average uplift rate of about 3 mm/year in the year 2003–2010. The Mosha fault illustrates left-lateral motion that could be explained with a fault that is locked up to 17–18 km depths and slips with 2–4 mm/year below that depth.

  • 44.
    Yazdanfar, Camellia
    et al.
    Department of Geology, University of Golestan, Iran; Department of Geology, University of Uroumieh, Iran.
    Nemati, Majid
    Department of Geology, Faculty of Science and Earthquake Research Center of Shahid Bahonar University of Kerman, Iran.
    Agh Ataby, Maryam
    Department of Geology, University of Golestan, Iran.
    Roustaei, Mahasa
    Geological Survey of Iran, Iran.
    Nilfouroushan, Faramarz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS. Geodata Division, Lantmäteriet, Gävle, Sweden.
    Stress transfer, aftershocks distribution and InSAR analysis of the 2005 Dahuieh earthquake, SE Iran2018Inngår i: Journal of African Earth Sciences, ISSN 0899-5362, Vol. 147, nr 86, s. 211-219Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, the authors studied the 2005 Dahuieh Zarand earthquake in SE Iran by combining Coulomb stress changes, InSAR study, locally recorded aftershocks and their spatial correlations, co-seismic slip distributions, Iso-seismal curves, and strong ground motion data. The event (MW 6.4) occurred in Kerman province, SE Iran, on February 22, 2005. The locally recorded aftershocks were used to calculate the Coulomb stress changes and the decay time based on Omori’s law. The decay time of aftershocks calculated by Omori’s law was about 500 days. A great correlation was particularly deduced from the spatial distribution of the aftershocks and areas of increased Coulomb stress for optimal strike slip faults. Moreover, using SAR Interferograms, we determined the postseismic surface deformations. Also, the majority of the coseismic slips occurred in the eastern part, where there was sparsely distributed aftershocks. The deformation maps showed active uplift for at least 300 days after the main shock. We reconciled time decays of the aftershocks with the postseismic uplifts, calculated from InSAR. In our model, which is based on after slip evolution, for one of the postseismic relaxation mechanisms, we found a proper correlation between the aftershock decay time and InSAR displacement maps to define postseismic motions. There is also a reasonable correspondence between the mainshock intensity, the acceleration map, and postseismic ground uplift, estimated by InSAR.

  • 45.
    Zarifi, Zoya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Geofysik..
    Nilfouroushan, Faramarz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Raeesi, Mohammad
    Department of Earth Science, University of Bergen, Bergen, Norway.
    Crustal stress Map of Iran: Insight from seismic and geodetic computations2014Inngår i: Pure and Applied Geophysics, ISSN 0033-4553, E-ISSN 1420-9136, Vol. 171, nr 17, s. 1219-1236Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We used the focal mechanisms of crustal earthquakes (depth <40 km) in the period 1909-2012 and the available GPS velocities, estimated from the data collected between 1999 to 2011, to estimate the magnitude and directions of maximum principal stress and strain rates in Iran. The Pearson product moment correlation was used to find the correlation between the stress field obtained from the focal mechanism stress inversion and that obtained using the seismic and geodetic strain rates. Our assumption is that stresses in a continuum are produced by tectonic forces and the consequent deformation on the crustal scale. Therefore, the direction of the stress and strain (or strain rate) are ideally be the same. Our results show a strong correlation between the directions of the principal components of stress and strain (rate) obtained using the different data/methods.  Using  weighted average analysis, we present a new stress map for Iran.

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