Document Type : Research Paper


1 Ph.D. candidate in geomorphology Dep. of geography, Ferdowsi University of Mashhad

2 Associate Prof., Dep. of geography, Ferdowsi University of Mashhad

3 Associate professor on geomorphology, Faculty of geological sciences, Complutense University of Madrid

4 Professor, Department of geology, Faculty of sciences, Ferdowsi University Of Mashhad

5 Department of geology, Payame Noor University of Mashhad, Mashhad, Iran

6 Radar system and services, Chandigarh, India


Extended Abstract
Mining (especially surface) is one of the major causes of land and environmental degradation globally. Environmental impacts such as deforestation, landscape degradation, alteration of stream and river morphology, widespread environmental pollution, siltation of water bodies, biodiversity loss, etc., have been noted to be associated with mining. Surface deformation is the biggest problem in open cast mines and their surrounding areas due to mining activities.  Surveying engineers study the amount of displacement in open pit mines by using leveling to calculate the amount of displacement and determine it. These methods are expensive and time consuming. Satellite images are considered as an important tool for land resource management due to the wide view that provide of an area and also due to its regular repetitive coverage. Interferometric Synthetic Aperture Radar (InSAR) is a useful tool in the study of surface displacements. The SAR interferometry concept has been introduced in the last 1980s.The objective of this study as an academic research is monitoring deformation using Persistent Scatterer Interferometry Synthetic Aperture Radar (PS-InSAR) method for managing a very rich iron ore resource in the eastern part of Iran named Sangan, near the Afghanistan boundary.
In this paper, surface deformation calculation based on the processing of PS-InSAR technique (Persistent Scatterers SAR Interferometry) have been carried out. For this study, according to the availability of data for study area 47 SLC images of Sentinel-1A covering the study area during the period of October 7, 2014 –July 7, 2020 are downloaded from European Space Agency website. Sentinel-1A acquired images with a swath width of 250 by 180, with revisiting time 12 days within the IW data acquisition mode, it is reduced to six days if the images acquired by the Sentinel-1B satellite are available. Sentinel-1 has launched on 4th April 2014 by ESA.
PS includes following steps:

Master image selection,
Co-registration data,
Reflectivity map generation
Amplitude stability index,
Persistent Scatterers Candidate selection (PSC),
PS point selection,
Multi-image sparse grid phase unwrapping,
Atmospheric phase screen estimation
Removal and PS phased reading
Displacement estimation.

Study area
Sangan Iron Ore Complex (SIOC) is located at latitude N 34°24’ to 34°55’   longitude E 60°16’ to 60°55’ in the Khorasan-e-Razavi Province, North-Eastern Iran. The iron ore deposit is about 20 km Northeast of Sangan town at about 1650 meters above sea level. Sangan Iron Ore Mines (SIOM) is one of the largest mineral areas in Iran, and also considered to be one of the Middle East’s richest deposits which are located in a rectangular area with 26km length and 8km width.
Results and Discussion
In this paper, the 47 scenes of IW SLC Sentinel-1A images, spanning the period from October 7, 2014–July 7, 2020 are accumulated displacement map and the time series of the deformation derived. The PS were selected on the basis of the ASI threshold value of 0.7, which signifies the stability of target points. The LOS displacement was improved by using APS and atmospheric phase delay correction. Later, the LOS displacement velocity on PS locations was estimated. The temporal coherence of all the selected PS was also tested. The PS points having ASI value of 0.7 and above, and temporal coherence of 0.9 and above, gave a relatively stable estimation of LOS velocity. We have identified 215377 Scatterers points. By imposing the standard threshold of 0.7 on ensemble coherence value, this amount decreased dramatically to 52449 PS points.  These factors make the chosen technique suitable for studies of surface deformations. The results showed that the deformation velocity in this area is -4.8 mm/yrs and maximum displacement-30mm. In order to verify the results, we collected the Total Station data and PS data for analysis and comparison. Due to the lack of data in the plain, the Total Station data is related to downslope areas and as a result, uplift of area has been used to validation the results. It has been observed that for the same area the Total Station value shows good agreement with the PS- InSAR result. However, there may be some errors due to the fact that the data are not synchronous and that the nature of the impression is different.
In the present study, PS-InSAR technique and C-band sentinel-1 data have been used for surface deformation monitoring in open cast mines of Sangan-Khaf, Khorasan Razavi. It can be concluded that monitoring the deformation of mined surfaces using traditional monitoring techniques such as field surveys and using Total Station, especially in large study areas, is time consuming. Since in using the interferometry methods in the study of open pit mines, the area covered by SAR images is much larger, so the use of this method will reduce costs. The results were assessed and validated using leavening data has been observed that, for the same area, the levelling value shows good agreement with the PS- InSAR result.


1-شامی، مشهدی، بابایی؛ سیاوش، حسینعلی، ساسان.(1398). آنالیز جابه‌جایی‌های بزرگ مقیاس با استفاده از فناوری تداخل‌سنجی راداری در معادن روباز (مطالعه‌موردی: معدن گل‌گهر سیرجان). نشریه علمی ترویجی مهندسی نقشه‌برداری و اطلاعات مکانی، 10(3)، صص41-51.
2-عابد، رحیم‌زادگان؛ فاطمه، مجید.(1397)، بررسی فرونشست زمین با استفاده از تصاویر ماهواره Sentinel به روش‌های جدید (PS-InSAR ) نرم‌افزار (SARPIROZ)، هفتمین کنفرانس ملی مدیریت منابع آب ایران، یزد.
3- Aydöner, C., Maktav, D., & Alparslana, E. (2004). Ground deformation mapping using InSAR. In Proceedings, ISPRS congress, Istanbul, Turkey.pp.161-168.
4- Bonì, R., Meisina, C., Cigna, F., Herrera, G., Notti, D., Bricker, S., ... & Ezquerro, P. (2017). Exploitation of satellite A-DInSAR time series for detection, characterization and modelling of land subsidence. Geosciences, 7(2), 25.pp.1-23.
5- Castello, L., & Macedo, M. N. (2016). Large‐scale degradation of Amazonian freshwater ecosystems. Global change biology, 22(3), pp.990-1007.
6- Devanthéry, N., Crosetto, M., Monserrat, O., Cuevas-González, M., & Crippa, B. (2014). An approach to persistent scatterer interferometry. Remote Sensing, 6(7), pp.6662-6679.
7- Ferretti, A., Prati, C. and Rocca, F., (2001). Permanent scatters in SAR interferometry. -IEEE Transactions on Geoscience and Remote Sensing, 39(1), pp. 8-20.
8-Geymen, Abdurrahman. (2014). “Digital Elevation Model (DEM) Generation Using the SAR Interferometry Technique.” Arabian Journal of Geosciences 7(2):pp.827–37
9- Goldstein, R. M., & Werner, C. L. (1998). Radar interferogram filtering for geophysical applications. Geophysical research letters, 25(21), pp4035-4038.
10- Govil, H., Chatterjee, R. S., Malik, K., Diwan, P., Tripathi, M. K., & Guha, S. (2018). IDENTIFICATION AND MEASUREMENT OF DEFORMATION USING SENTINEL DATA AND PSINSAR TECHNIQUE IN COALMINES OF KORBA. International Archives of the Photogrammetry, Remote Sensing & Spatial Information Sciences, pp. 427-431.
11- Huang, C., Xia, H., & Hu, J. (2019). Surface deformation monitoring in coal mine area based on PSI. IEEE Access, 7, pp.29672-29678.
12- Ishwar, S. G., & Kumar, D. (2017). Application of DInSAR in mine surface subsidence monitoring and prediction. Current Science,pp. 46-51.
13- Jiang, L., Lin, H., Ma, J., Kong, B., & Wang, Y. (2011). Potential of small-baseline SAR interferometry for monitoring land subsidence related to underground coal fires: Wuda (Northern China) case study. Remote Sensing of Environment, 115(2), pp.257-268.
14- Kumar, S., Kumar, D., Chaudhary, S. K., Singh, N., & Malik, K. K. (2020). Land subsidence mapping and monitoring using modified persistent scatterer interferometric synthetic aperture radar in Jharia Coalfield, India. Journal of Earth System Science, 129(1), pp.1-10.
15- Ng, A. H. M., Ge, L., Zhang, K., & Li, X. (2011). Application of persistent scatterer interferometry for land subsidence monitoring in Sydney, Australia using ENVISAT ASAR data. In 34th International Symposium on Remote Sensing of Environment.pp1-4
16- Olfindo Jr, N., Manalili, M. A., Quides, R. R., Aranda, J. O., & Corpuz, G(2018).OPEN-PIT MINING MONITORING USING C-BAND INTERFEROMETRIC SAR.pp1-7
17- Paradella, W. R., Ferretti, A., Mura, J. C., Colombo, D., Gama, F. F., Tamburini, A., & Silva, A. Q. (2015). Mapping surface deformation in open pit iron mines of Carajás Province (Amazon Region) using an integrated SAR analysis. Engineering Geology, pp.193, 61-78
18- Pawluszek-Filipiak, K., & Borkowski, A. (2020). Integration of DInSAR and SBAS Techniques to determine mining-related deformations using sentinel-1 data: The case study of Rydułtowy mine in Poland. Remote Sensing, 12(2), pp.242-265
19- Prati, C. L. A. U. D. I. O., Ferretti, A., & Perissin, D. (2010). Recent advances on surface ground deformation measurement by means of repeated space-borne SAR observations. Journal of Geodynamics, 49(3-4), pp.161-170.
20- Sahu, P., Pradhan, M., Jade, R. K., & Lokhande, R. D. (2016). Study the variations of sinkhole depth with respect to working height in underground coal mines. Recent Adv. Rock Eng, 91, 547-551.
21- Strozzi, T., Wegmuller, U., Tosi, L., Bitelli, G., & Spreckels, V. (2001). Land subsidence monitoring with differential SAR interferometry. Photogrammetric engineering and remote sensing, 67(11), pp.1261-1270.
22- Tomiyasu, K. (1978). Tutorial review of synthetic-aperture radar (SAR) with applications to imaging of the ocean surface. Proceedings of the IEEE, 66(5), pp.563-583.
23- Zhang, L., Ge, D., Guo, X., Liu, B., Li, M., & Wang, Y. (2020). InSAR monitoring surface deformation induced by underground mining using Sentinel-1 images. Proceedings of the International Association of Hydrological Sciences, 382, pp.237-240.
24-Zhu, Y., Ding, X., Li, Z., & Luo, Y. (2014). Monitoring of Surface Subsidence of the Mining Area Based on SBAS. JCP, 9(5), pp.1177-1184.