Contents lists available at ScienceDirect Journal of Arid Environments journal homepage: www.elsevier.com/locate/jaridenv Land subsidence in Isfahan metropolitan and its relationship with geological and geomorphological settings revealed by Sentinel-1A InSAR observations Abolghasem Goorabi a,∗ , Mostafa Karimi a , Mojtaba Yamani a , Daniele Perissin b,c a FacultyofGeography,DepartmentofPhysicalGeography,UniversityofTehran,Tehran,Iran b PurdueUniversity,LyleSchoolofCivilEngineering,FacultyofGeomatics,WestLafayette,IN,UnitedStates c RadarandSoftwareEngineeringResearchCompany,HongKong,China ARTICLEINFO Keywords: Subsidence Isfahan metropolitan Landforms Geological and geomorphological units PS-InSAR ABSTRACT Recent reports from Isfahan, Iran, have proclaimed cases of land subsidence arising from persistence of drought events and groundwater overexploitation. In this light, the present study attempts to conduct an PS-InSAR analysis of subsidence events using the Sentinel–1A Synthetic Aperture Radar imagery technique, in order to develop a subsidence map of the target study region, covering the period from October 16, 2014 to November 22, 2019 as well as to investigate its relation to geological/geomorphological factors. Toward this end, the methodology proceeds to detect land subsidence phenomenon across the Isfahan Metropolitan area, situated on theZayande-RudRiverTerrace(ZRT)andIsfahanAlluviumPlain(IAP).Atotalof198Sentinelimageswereused to derive deformation specifics observed throughout ZRT & IAP by dint of incorporating ascending and des- cending passes of the InSAR technique. As maintained by spatial and temporal variation maps of surface de- formations in the urban regions of Isfahan, ZRT & IAP have undergone various orders of subsidence throughout the observation period, at an estimated rate of −5 to −100 mm/year. Overall, land subsidence appears to increase from south towards the northern, northeastern, and eastern sectors of Isfahan Metropolitan, while the southernsectorsarenearlyastablearea.Thisstudyindicatesthatthespatialsubsidencepatternduringthestudy period corresponds closely to the spatial distribution of ZRT & IAP in the Isfahan Metropolitan area. 1. Introduction Among various classes of dispositional geomorphic landforms, al- luvium plains and river terraces, have galvanized the attention of a vast body of academic pursuits in various fields of; active tectonics, arche- ological excavations, civil engineering projects, hydro-geology, supply of construction materials, natural hazards, paleo-environmental and climatic evolution, petroleum geology, sedimentology, study of base- level changes, geomorphology and groundwater resource explorations (Blair and McPherson, 1994; Porter and Guccione, 1994; Enzel et al., 2000; Mountney, 2005; Parsons and Abrahams, 2009; Laity, 2009; Santangelo et al., 2012; Goorabi and Yamani, 2012; Fenton and Pelletier, 2013; Vandenberghe, 2015; Welland, 2015; D'Arcy et al., 2015; Popeetal.,2016; Arzhannikova et al., 2018; Jordan et al., 2019). River's terraces are defined as well-developed, flat surfaces close to (former) rivers, representing an erosion-stricken floodplain (Vandenberghe, 2015). River's terrace staircases develop as a joined outgrowth between tectonics and climate change. Tectonic subsidence, otherwise referred to as uplift, entrains certain changes in the base-level and course of rivers; the result of which is the formation of multiple terraces adjacent to (former) rivers. Climate change, on the other hand, may engender alterations in river system energy, sea-level (lake level), vegetation and slope of a river, as well as its catchment, and eventually further transformations in river terraces. In addition to river valleys, terraces may also form around rivers flowing on alluvial fans. Alluvial plains, however, are generally situated at the toe of an alluvial fan, considered the final destination of rivers and alluvial sediments. Alluvium plains and river terraces (current and old) are prominently known as abundant reservoirs of fresh water and fertile soils, engendering suitable conditions for agriculture activities and categorized as preferred sites for human civilization. As a result, many villages and cities around the globe are centralized around such areas (“River Terrace - an River Terrace over- view | ScienceDirect Topics,” n.d.), particularly in arid regions, such as the Isfahan Metropolitan area in Central Iran. Isfahan province, geographically located in the central region of Iran, consists of the Isfahan Metropolitan, which itself is situated on the ZRT and alluvium plain (current and old), primarily comprised of alluvium sedi- ments, silt and clay. These Quaternary sediments originate from the sur- rounding mountains and are periodically deposited as river terraces and https://doi.org/10.1016/j.jaridenv.2020.104238 Received 9 March 2020; Received in revised form 3 May 2020; Accepted 3 June 2020 ∗ Corresponding author. Faculty of Geography, Department of Physical Geography, University of Tehran, Enqlab Avenue, Tehran, Iran. E-mail address: goorabi@ut.ac.ir (A. Goorabi). Journal of Arid Environments 181 (2020) 104238 0140-1963/ © 2020 Elsevier Ltd. All rights reserved. T