جستجوی مقالات مرتبط با کلیدواژه « land subsidence » در نشریات گروه « عمران »

Land subsidence can be counted as a vital concern for human beings due to its harmful effects. The impacts of land subsidence can be seen in several forms, such as cracks in buildings, damage of infrastructures (roads and bridges), tilting and damaged houses, and increases in flooding inundation areas (Gumilar et al., 2015). Overusing of water and soil resources, which can threaten nature and human life, is considered as one of the main reasons for some natural hazards like land subsidence.

The subsidence caused by the increase in the exploitation of groundwater resources has a long history compared to its restoration potential in some internal regions of Iran. In recent years, land subsidence has caused serious environmental hazards in various plains and regions of Iran. Land subsidence is one of the environmental hazards that humans have faced in recent decades due to uncontrolled extraction of groundwater resources. This phenomenon, like other hazards such as earthquakes, droughts, floods, storms, landslides, etc., is one of the obstacles to socio-economic and development. The subsidence phenomenon is usually associated with many risks. This phenomenon can cause infrastructural, natural and ultimately damage to society and the economy. In recent years in Iran, with the increase in subsidence, buildings, airports, bridges, tunnels, streets, rail and road lines have been severely damaged. For this purpose, in this study, the amount of land subsidence in Kerman airport was analyzed using Sentinel-1 satellite radar images from 2014 to 2020 in Snap software using radar interference measurement technique. The subsidence rate of this range from 2014 to 2017 is at least 3.3 cm and maximum 6 cm, from 2017 to 2020 at least 3.6 cm and maximum 2.13 cm and from January 2020 to April was a minimum of 0.03 cm and a maximum of 13.2 cm, which shows a significant increase. Increased utilization of groundwater resources, compaction due to land drainage and compression due to the imposition of heavy loads (aircraft, structural loads, etc.) can be mentioned as main factors of subsidence in this area.

Land subsidence due to groundwater over-exploitation is a man-made hazard, and identifying those areas vulnerable to subsidence is of undeniable significance. The present study applies the ALPRIFT method to assess the vulnerability of land subsidence in the Marand plain located in East Azerbaijan province in Iran, which has been at the risk of subsidence in recent years. In the framework of this method that has been developed recently, seven incorporated data layers comprise aquifer media, land use, groundwater pumping, net recharge, aquifer thickness, distance from fault, and water table decline. The data layers were prepared by GIS processing, and the prescribed rates were assigned to the data layers. Then, the data layers were prioritized based on the recommended weights, and the vulnerability map of the region was delineated. In this paper, with respect to the significance of water table decline, two strategies were used in the process of preparing this data layer. In the first strategy, the difference in water levels was used in the first and the last months of a specific year. Based on this strategy, the decline of water table was prepared during 2011-2018. In the second strategy, the trend or slope of water table decline during the same period was used to prepare this data layer. The goodness-of-fit for the vulnerability map and InSAR processing were evaluated by ROC curve. The comparison of the results showed that the estimation of subsidence vulnerability by the first strategy varied for different years; however, the second strategy provided the vulnerability to subsidence regardless of seasonal and temporal fluctuations. Moreover, the result revealed that the southeast and southwest parts of the plain, the Marand city and the Yamchi and Kushksaray residential areas were located in the vulnerable area to subsidence. Moreover, the average subsidence in this plain is 2 cm based on the results of InSAR processing during 2017-2018. The results of this research can be utilized in the planning and management of groundwater abstraction to control subsidence.

Monitor and detection of displacement field due to changes in land surface are one of the practical and important studies in different topics of the Geodesy, Geological and geophysical which have a significant role in trends and preventing natural disasters such as earthquake, subsidence and landslide. In the meantime, there are different methods for detection this displacement and geodetic measurement, that among them, Interferometric Synthetic Aperture Radar (InSAR) with a feature wide spatial coverage, fine spatial and time resolution and high accuracy has become one of the important and significant techniques. Land subsidence due to groundwater extraction has been a common geohazards in many arid countries and districts of the world. In Iran, this is a serious challenge for many regions, particularly in the plains with arid and semi-arid climate, for example, Mashhad valley, Hashtgerd, Yazd and Golpayegan plains. Gazvin plain is one of these regions where the land subsidence has seriously developed. This region is located in the north-central Iran, with an area size of about 4430 km2. Gazvin plain in terms of industrial, agriculture and population point is one of the important plain in Iran. In recent years, high rate of extracting water from underground source due to agricultural activity, industrial and population development caused decreasing the groundwater level, so because of the groundwater level downfall, subsidence occurs and it’s trace is seen as cracks and fractures in the ground surface. Studies show that a large area in Qazvin plain is subject to the land subsidence induced by overexploitation of groundwater for the purposes of agricultural, industrial and population development. Therefore, this research study on the pattern and rate of subsidence occurred in Qazvin plain between 2003 and 2010, using radar is Interferometric synthetic aperture radar (InSAR) techniques. The data set consists of 20 and 18 images of descending tracks D192 and D421 during 2003 to 2010. We processed radar data with the open source software StaMPS/MTI (Stanford Method of PS/Multi-Temporal InSAR). The interferograms are corrected for the phase signature due to orbital separation using precise doris orbital data for ENVISAT satellite which is provided by DEOS are stored in a binary format (ODR) that believed to have a radial precision of 5-6 cm. then the 90 m SRTM DEM has been used to estimate the topographic phase contribution. The atmospheric phase delay in each individual interferograms corrected using the retrieved water vapors from MERIS data. We also improve signal to noise ratio of each differential interferogram using a Goldstein filter. The time series analysis of permanent scatterer (PS) and small baseline subset (SBAS) algorithms are used for deformation time series analysis. The time series results show that a considerable and continuously land subsidence in the study area. Results show a good agreement between the PS and SBAS time series, both of two approaches identify peak amplitude of ~ 30-35 mm/year for the 2003-2010 times period. With comparison width and extent of subsidence of InSAR results and plain wells density map of Qazvin plain determines the subsidence occurred in the area with the density of deep wells to extract groundwater and subsequent subsidence occurred in this area.

Land subsidence phenomenon caused by natural factors and human activities in different parts of the world. This phenomenon in recent years is appeared in Iran, especially in Fars province due to indiscriminate withdrawal of groundwater, drought and other factors. Land subsidence caused lots of damages to agricultural lands, residential buildings, roads, and other structures and generally created environmental, social and economicAL problems. In this research a case study was performed on the villages of Marvdasht plain in order to study the effective factors and parameters and evaluate the influence of each one on land subsidence. And also was examined how to determine and evaluate the main effective parameters such as water levels falling, material and thickness of soil layers especially fine-grained, geotechnical properties of soil layers. Results showed to perform of subsidence calculations the data and requirement information should be prepared accurate and complete as much as possible. It should be noted that the characteristics and different statues of each parameter must be considered. For example, the amount of settlement is different in Various depth due to same water falling or same thickness of layers.