Showing 4 results for Insar
Mohammadreza Goodarzi, Maryam Sabaghzadeh, Amirreza Rajabpour Niknam,
Volume 0, Issue 0 (3-1921)
Abstract
In arid and semi-arid, groundwater is more important for humans and ecosystems than surface water. Land subsidence is caused by the pumping and uncontrolled use of groundwater in an area. When harvested quantities aren’t compensated by rainfall, it causes damages such as road failures, destruction of residential areas, railways, and water and gas pipelines. Yazd-Ardakan plain is one of the important plains of Yazd province, which has 75% of the population density of the province and the most industrial centers. In addition, this plain has been banned by the Ministry of Energy due to a sharp drop in groundwater levels. In this study, the amount of subsidence was obtained and compared using 4 SLC images of the C-band of the Sentinel-1 satellite and the radar differential interferometry method from 2017 to 2021. The maximum amount of subsidence in 2017 was 13 cm and in 2020 and 2021, 9 cm, which is related to the Shamsi region in the area between Meybod and Ardakan. Also, to ensure the results of satellite images, they were compared with the results of the accurate leveling method performed by the Iran National Cartographic Center. It was observed that sentinel images have a good ability to estimate the amount of subsidence. According to the study of groundwater consumption and depletion statistics in recent years, possible reasons for the reduction of subsidence in the study area can be management measures such as water transfer to this basin, change in agricultural practices and reduction of groundwater depletion compared to years ago in this area.
Abolghasem Goorabi,
Volume 21, Issue 60 (3-2021)
Abstract
Radar sensors obtain regular and frequent radar images from which ground motion can be precisely detected using a variety of different techniques. The interferometric synthetic aperture radar (InSAR) is utilized to retrieve the spatial characteristics of the largest coseismic landslide Maleh-Kabood, induced by the Ms 7.3 Azgleh earthquake in Kermanshah Province, Iran. The available seven interferometric pairs with good coherence selected from the Sentinel 1, 2 imagery data covering the NW-Zagros mountainous area are used in the study. The post-seismic topographic change relative to the pre-seismic over the landslide area is spatially mapped from the persistent scatterer network adjustment solution. The quantitative estimation of local elevation change, mass sliding volume and deposit thickness associated with the landslide is conducted. The spatial pattern of mass movement suggests that the giant landslide is characterized by a major sliding length of 3570 m along the NW–SE directions with an extension width of 1500-2300 m along the Maleh-Kabood and Ghoch-Bashi gully respectively, and a peak height change of 20 m in the vertical direction neat mountain ridge. The affected area of landslide mass movement reaches 6.0 km2 (577 Hectares) with the volume up to 500 million m3. Comparative studies indicated that the Maleh-Kabood landslide is the largest landslide in Iran over the past few centuries. The study also demonstrates the potential of InSAR technique as an alternative to allow the quantitative measurement of mass wasting volume associated with earthquake-induced giant landslides.
Roghayeh Delaram, Samad Fotohi, Mohsen Hamidianpoor, Morteza Salari,
Volume 24, Issue 72 (6-2024)
Abstract
The subsidence phenomenon is considered one of the most frequent hazards occurring worldwide and imposing irreparable damages every year. This phenomenon affects the ground’s surface and its layers and causes the ground deformation. It can be referred to as a morphological phenomenon that is associated with the gradual sinking of the ground and the vertical movement of materials. Among the various methods used to study the land subsidence pattern, the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique has provided more accurate results. Therefore, this technique was used to investigate the subsidence rate in Mashhad plain from 2003 to 2010 and the Envisat ASAR (C-band) and Sentinel-1 ASAR (C-band) satellite images were employed during the year 2019. The results show that the highest subsidence rate of about 44 cm occurred in Qasem Abad and Kalateh-ye Barfi lands from 2008 to 2010. A subsidence rate of about 37 cm was also observed in the same area from 2007 to 2009. The interpolation results using piezometer well statistics show a decrease in groundwater levels in this area and confirm the accuracy of the results.
Sayyd Morovat Eftekhari,
Volume 24, Issue 74 (12-2024)
Abstract
One of the consequences of the earthquake can be changes in the elevation levels of the unevenness in the area of occurrence. These changes at the level of the region will not be the same and the amount will be different under the influence of several factors such as: earthquake intensity, landforms, geo-material, and structure geological... The purpose of this research is to measure the geomorphometric changes caused by the earthquake of 17th February 2021 at the level of Dana County using the radar technique differential SAR Interferometry. To achieve this goal, taking into account the appropriate coverage and measurement accuracy of the Sentinel 1 radar satellite images from two image scenes related to the earthquake area for the dates before (2021.02.08) and after the earthquake (2021.02.20) from the organization's website. European Space Agency (ESA) was received, after performing the process and data analysis Differential Synthetic Aperture Radar Interferometry (D-InSAR), it was found that after the earthquake dated 2021,02,17, a part of the studied area was affected by positive elevation changes with a rise of 0.11 cm and Negative changes of -0.6 cm subsidence have been encountered. These positive changes (uplift) are more noticeable near the epicenter of the earthquake in the east of Dena, and the negative changes (subsidence) are quite evident with the Syncline Valley on which Khorasan Rivers is located. And in dealing with the faults, changing the geological structure, geo-material of the region, it has a special irregularity.
