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Seismicity of the northern part of Egypt. Earthquakes recorded by the Egyptian National Seismic Network from 1997 to 2008. Different symbols correspond to different rates of magnitude displayed in the legend. The 12th October 1992 earthquake has been recorded before installing the Egyptian National Seismic Network
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Subsidence, earthquakes, landslides represent trigger of many ground motion events biasing also building stability. The related deformation is often caused by human activities such as water and oil pumping, slopes undercut by roads, mining etc. This problem affects largely the built-up Greater Cairo metropolitan area, which, as any part of the worl...
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... third layer is the basalt layer with a thickness ranging from 6 m to 60 m. Seismic hazard in northern Egypt (Figure 2) is primarily caused by the interaction amongst the African, Eurasian and Arabian tectonic plates, as well as the Sinai micro-plate which is partially separated from the African plate by rifting along the Gulf of Suez. In addition, the activity along these plate margins, mega-shear zones running from southern Turkey to Egypt have been defined by a number of studies (e.g., Neev, 1975). ...
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Space borne differential synthetic aperture radar interferometry (DInSAR) has already proven its po-tential for mapping ground deformation phenomena, e.g. earthquakes, volcano dynamics, etc cov-ering in continuity large areas. The innovative Persistent Scatterers Interferometry (PSI) technique, which overcomes several lim-itations of conventional S...
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... Consequently, the major research findings were compared to the previous research in the study area. Two literature research were involved [52,53] because their investigations utilized InSAR data within our study period. Poscolieri et al. [52] detected ground deformation in the Greater Cairo Metropolitan Region from 2003 to 2009 using ASAR Single Look Complex VV-polarization scenes in descending mode. ...
... Two literature research were involved [52,53] because their investigations utilized InSAR data within our study period. Poscolieri et al. [52] detected ground deformation in the Greater Cairo Metropolitan Region from 2003 to 2009 using ASAR Single Look Complex VV-polarization scenes in descending mode. They employed Interferometric Stacking and Persistent Scatterers Interferometry to retrieve the displacement. ...
Ground deformation is one of the crucial issues threatening many cities in both societal and economic aspects. Interferometric synthetic aperture radar (InSAR) has been widely used for deformation monitoring. Recently, there has been an increasing availability of massive archives of SAR images from various satellites or sensors. This paper introduces Multi-Satellite SBAS that exploits complementary information from different SAR data to generate integrated long-term ground displacement time series. The proposed method is employed to create the vertical displacement maps of Almokattam City in Egypt from 2000 to 2020. The experimental results are promising using ERS, ENVISAT ASAR, and Sentinel-1A displacement integration. There is a remarkable deformation in the vertical direction along the west area while the mean deformation velocity is −2.32 mm/year. Cross-validation confirms that the root mean square error (RMSE) did not exceed 2.8 mm/year. In addition, the research findings are comparable to those of the previous research in the study area. Consequently, the proposed integration method has great potential to generate displacement time series based on multi-satellite SAR data; however, it still requires further evaluation using field measurements.
... Ground mass movements cause landslides, subsidence, and earthquakes. Human activities like water and oil pumping, road cutting, mining, and others cause geological disasters (Poscolieri et al., 2011). The Mokattam Plateau area was affected by a number of landslides over the past few years. ...
Landslides occurred in the Ain Moussa area, north of Mokattam, Egypt. The study aims to detect landslide causes in fractured limestone using electrical resistivity tomography. The result of the electrical resistivity tomography profiles showed that there are two main layers: the first is a high-geoelectrical resistivity layer of fractured limestone covered in some places by backfill sediments, and the second is a low-geoelectrical resistivity layer of shale below the limestone. In between the two layers is a zone that is holding the weight of water leaking from the surface; it has a medium resistivity value. These results were compared with available satellite images. Based on the results, it was found that there is a layer of fractured limestone on the surface. The top part of it is dry, but the bottom part has water leaking from the surface, which has the biggest effect on landslides. The shale layer's surface is irregular, as it was discovered that the most influential part is the low part of the shale's surface, as it contains a high-water content and thus is more affected, and it is where the landslide occurred. It is possible to identify the deepest points of the shale layer, on which the water leaking from the surface collects, along the plateau, as these places are more likely to cause landslides.
... What enlarges the damage to the historic structures in Historic Cairo, under the effect of the groundwater increase is the type of the foundation soil. Many studies were carried out for the characterization of the foundation soil of Historic Cairo [3] [10] [11] [12] [13] [14]. The studies included data on the boreholes carried out to different depths from the natural ground level and the soil geological data for large depths. ...
The cemetery of the royal family, who ruled Egypt from 1805 to 1952, is one of the masterpieces of the UNESCO World Heritage Site of Historic Cairo. It is a complex building from massive stone masonry walls supporting hemispherical domes and is very rich with the marble decorative elements. Unfortunately, it suffers nowadays from serious cracking due to on-going structural damage. Almost all the structural elements are cracked. Besides, the continuous rise in the groundwater table affects both its structural stability and aesthetics. A detailed inspection was carried out to identify and explain all the manifested damage by the structural elements of the cemetery. The differential settlement damage was found to be very noticeable in the form of many diagonal cracks that are active and threaten the overall stability of the cemetery. The construction history was investigated and found to have a clear effect on the noticed damage. Examination of the construction materials and deterioration products was carried out by inspecting representative samples of the stone, the marble, the mortar, the plaster and the salt. They were examined using different analysis techniques including the Polarized Microscope, the Stereo Microscope, the X-Ray Diffraction (XRD), and the Scanning Electron Microscope (SEM) provided with Energy-Dispersive X-ray spectroscopy (EDX) unit. This examination helped in identifying the type of the used stone, the mortar components, the types of salts affecting the structure, and the deterioration manifested by the marble. It seems that the cemetery needs an urgent conservation project to stop the deterioration and keep it safe for the next generations.
... Aly et al. (2012) has reported that the rate of vertical movement in Greater Mahala city and Mansoura city was about are 5 mm/year and 9 mm/year downward, respectively. Additionally, Poscolieri et al. (2011) have reported the vertical movements in the Greater Cairo metropolitan region over the period 2003-2009 ranging from 3.8 mm/year upward to 7 mm/year downward. Sneed et al. (2001) have reported similar results of integrated complex land subsidence or uplift in other geographic locations. ...
Nile Delta, one of the most populated deltas around the world, is suffering from subsidence due to the natural compaction of its sediment. Land subsidence has a great impact on the infrastructure, economic, and social. This study investigatesthe evaluation of the land subsidence in Nile Delta using GNSS measurements. Eight stations of GNSS points through period 2013–2015 distributed around Nile Delta and the Northern part of Egypt are utilized using differential GPS with nine IGS stations by GAMIT/GLOBK V. 10.61. The main objective is to monitor the spatiotemporal variations of land surface within the Nile Delta by time series analysis of the ellipsoidal height. The northern part of Egypt can be divided into three major parts; the western part shows subsidence rate of 2 mm/year downward; Nile Deltaof 2.5 to 10 mm/year downward from west to east and the eastern part shows an uplift.
... This situation has become a concern for the area's residents but a better understanding of the processes occurring there can aid in deciding a suitable response. (Poscolieri et al., 2011). (Aly, 2006) has reported that the vertical land motions of about ± 5 mm/year within the central Delta area for the period 1993 -2000. ...
... Additionally, (Aly et al., 2009;Poscolieri et al., 2011) ...
The study of the crustal movements plays a very important role in the geodynamical research. It helps in understanding the properties of the regional and local scales of our Earth’s system. The Nile Delta is home to around 40 % from Egypt’s population and most of Egypt’s farmland and agricultural production. This area is currently threatened by Mediterranean Sea waters due to factors such as sediment starvation, climate change, and sea level fluctuations as well as subsidence. The low elevation and relief of the Nile Delta exposes many coastal communities, including the city of Alexandria, to potential inundation. This situation has become a concern for the area’s residents but a better understanding of the processes occurring there can aid in deciding a suitable response. Recent studies have documented Holocene subsidence rates in the northeast part of the Nile Delta that average up to 8mm/year. In this study, Global Navigation satellite system (GNSS) techniques are used to measure the land subsidence rates on the north-central and north-western Nile Delta.
The GNSS technique has become the geodetic method choice studying a wide range of geophysical phenomena. GNSS measurements are now in use to the recent crustal movements specially land subsidence and its relation to seismicity and tectonics along the north Egypt, Nile Delta and surrounding area. A geodetic network consists of 8 stations was belong to Egyptian Permanent GPS Network (EPGN) demonstrated by NIRAG. 66 day of GNSS measurements collected and combine in 13 campaign mode during the period from 2013 to mid of 2015. The data was processed, adjusted and analyzed using several processing techniques such as Relative positioning (DGNSS) and Precise Point Positioning PPP using Scientific software e.g. Bernese Ver. 5.2, GAMIT/GLOBK Ver. 10.61 and PPP online service to derive velocity vectors in International Terrestrial Reference Frame (ITRF08) and principal components of crustal strains along the northern Egypt and Nile Delta area. The estimated annual horizontal velocity of the selected stations in northern Egypt and Nile Delta region using GAMIT/GLOBK in ITRF 2008 is about 23.6 ± 0.3 mm/yr in the east direction, while 18.5 ± 0.3 mm/yr in the north direction. The average residual velocity rate for all the stations, estimated from the subtraction of annual horizontal velocity in ITRF 2008 from the velocity of each point at the African plate deduced from NUVEL 1A, move in the direction of west to southwest direction, while ALEX stations moves in the direction of east to southeast direction with unlogic value in the horizontal velocity this indicates that it had a lot of noise and a bad installation.
The annual vertical velocity shows that, all station suffer from subsidence rate increase from west to east with average rate of -4.9 ± 0.95 mm/year. while the Saini region shows uplift about 0.04 ± 1.11 mm/year. The values of the vertical movement derived from the suffer indicates that the maximum value of subsidence is located at Damietta Branch and Lake Manzala.
The deformation parameters were computed by dividing the area into five blocks. The horizontal components of the velocity vectors were used to estimate the deformation parameters. Dilatation, maximum shear strains, principal axes of strains and blocks rotation are clear portraying for the crustal deformation of northern Egypt and Nile Delta area. According to the strain fields, which were calculated for the different epochs of measurement, northern Egypt suffers from stress. The distribution of principle strain shows that the extension is prevailing in the area. The maximum extension strain founded at block VI in NE-SW direction, while the minimum extension strain founded at block I in the NE-SW direction. The estimated total amount of average rate of areal compression strains accumulation is concentrated in the southeast of Cairo area during the period from 2013 to 2015. Dilatational strains show patches of high and medial values of the compressional strain. Additionally, there are low compressions in the western parts of the area under study. The total amount of maximum shear strain accumulation during the same interval is relatively small and lies in the lowest class and is prevailed in the middle of the study area between the Nile valley and the Gulf of Suez. Medial shear strain part covers some parts in the area while the low shear strain rate covers the southern parts of the area under study.
... Earlier interferometric applications in the Nile Delta (Aly et al., 2009(Aly et al., , 2012Becker & Sultan, 2009;Poscolieri et al., 2011) had limited spatial coverage and/or used a small number of scenes (5 to 14 scenes; Aly et al., 2012). To the best of our knowledge, this work is the first of its kind in extracting deformational patterns across the entire length and width of a river delta using radar interferometric techniques. ...
Persistent scatterer interferometric analyses were conducted on a stack of 84 Envisat ASAR scenes spanning 7 years (2004 to 2010) over the entire Nile Delta of Egypt and surroundings (area: 40,416 km2) to monitor the ongoing spatial and temporal land deformation, identify the factors controlling the deformation, and model the interplay between sea level rise and land subsidence to identify areas and populations threatened by sea encroachment by the end of the 21st century. Findings include: (1) general patterns of subsidence (average rate: −2.4 mm/yr) in the northern delta, near‐steady to slight subsidence in the southern delta (average rate: 0.4 mm/yr), separated by a previously mapped flexure zone (minimum width: 20–40 km) undergoing uplift (average rate: 2.5 mm/yr); (2) high subsidence rates (up to −8.9 mm/yr) over the north central and northeastern delta (area: ~4815 km2), possibly due to compaction of recent (<3500 years old), thick (>5m) silt and clay‐rich Holocene sediments; (3) high subsidence rates (up to −9.7 mm/yr) in areas where the highest groundwater extraction rates were reported in southern delta (Menoufia governorate) and in reclaimed desert land in the western delta (Beheira governorate); (4) high subsidence rates (up to −9.7 mm/yr) over onshore gas fields, notably the Abu Madi gas field, where high gas extraction rates have been recorded; (5) using extracted deformation rates, high‐resolution TanDEM‐X digital elevation model, a eustatic sea level rise of 0.4 m, and applying a bathtub inundation model, an estimated 2660 km2 in northern delta will be inundated by year 2100.
... PSI has shown its great ability to measure ground deformation in urban areas, independently the cause, for instance water pumping 7,8 , tunneling 9 urban active faults 10 or multi-source causes 11,12,13 . In the case of Rome City (Italy) 14 , in Cairo City (Egypt) 15 and in the Greater Pearl River Delta 16 have shown excellent results over urban centers, concerning ground deformation monitoring induced by rapid urbanization, using multitemporal SAR interferometry. The aim of this study is the surface deformation monitoring within Alexandria City (Egypt) using the PSI approach and correlate its result with different local land cover types mapped by Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image data. ...
... There are different methodologies in differential interferometry (e.g., two-pass, three-pass, and four-pass interferometry) and with relatively new advanced algorithms (e.g., the Permanent Scatterers (PS) and the Small BAseline Subset (SBAS)) [9][10][11]. These techniques enable the mapping of subtle vertical surface movements (e.g., due to subsidence) down to millimeters [12][13][14][15][16][17]. ...
... Numerous studies have recorded the vertical land subsidence velocities of the Nile Delta by using in situ observations [23,26,[28][29][30][31][32] as well as remote sensing techniques [15,19,[33][34][35][36][37][38][39][40]. Across the northern Delta, about 87 continuous sediment drill cores from the National Museum of Natural History (NMNH) of the Smithsonian Institution were used to provide estimates of its subsidence [41]. ...
... In recent years, a number of researchers have been interested in measuring land subsidence rates in the Nile Delta region by using radar interferometric techniques [15,19,31,38,39,43]. However, most The second estimation of the displacement using the Small Baseline Subset (SBAS) technique [11] was performed to recover the final processed displacement time series from the atmospheric artifacts, taking into account a coherence threshold applied to the input stack of the unwrapped phase ( Figure 10). ...
The accurate detection of land subsidence rates in urban areas is important to identify damage-prone areas and provide decision-makers with useful information. Meanwhile, no precise measurements of land subsidence have been undertaken within the coastal Port-Said City in Egypt to evaluate its hazard in relationship to sea-level rise. In order to address this shortcoming, this work introduces and evaluates a methodology that substantially improves small subsidence rate estimations in an urban setting. Eight ALOS/PALSAR-1 scenes were used to estimate the land subsidence rates in Port-Said City, using the Small BAse line Subset (SBAS) DInSAR technique. A stereo pair of ALOS/PRISM was used to generate an accurate DEM to minimize the residual topography effect on the generated interferograms. A total of 347 well distributed ground control points (GCP) were collected in Port-Said City using the leveling instrument to calibrate the generated DEM. Moreover, the eight PALSAR scenes were co-registered using 50 well-distributed GCPs and used to generate 22 interferogram pairs. These PALSAR interferograms were subsequently filtered and used together with the coherence data to calculate the phase unwrapping. The phase-unwrapped interferogram-pairs were then evaluated to discard four interferograms that were affected by phase jumps and phase ramps. Results confirmed that using an accurate DEM (ALOS/PRISM) was essential for accurately detecting small deformations. The vertical displacement rate during the investigated period (2007-2010) was estimated to be -28 mm. The results further indicate that the northern area of Port-Said City has been subjected to higher land subsidence rates compared to the southern area. Such land subsidence rates might induce significant environmental changes with respect to sea-level rise.
... Measuring the subsidence rates within the Nile Delta has also been a major focus throughout the past few decades (Stanley and Wrane, 1993;Ali et al., 2009;Becker and Sultan, 2009;Poscolieri et al., 2011;Marriner et al., 2012). Rates and distribution of subsidence are of high variability, they generally range between 0.1 mm and 15 mm per year (Stanley, 1988;Becker and Sultan, 2009). ...
This paper investigates the relevance of landforms to the subsidence of the Nile Delta using a high resolution topographic digital elevation model (DEM) and sets of multi-temporal Landsat satellite images. 195 topographic map sheets produced in 1946 at 1:25,000 scale were digitized, and the DEM was interpolated. The undertaken processing techniques have distinguished all the natural low-lying closed depressions from the artificial errors induced by the interpolation of the DEM. The local subsidence of these depressions from their surroundings reaches a maximum depth of 2.5 m. The regional subsidence of the Nile Delta has developed inverted topography, where the tracts occupied by the contemporary distributary channels are standing at higher elevations than the areas in between. This inversion could be related to the differences in the hydrological and sedimentological properties of underlying sediments, as the channels are underlain by water-saturated sands while the successions of clay and silt on flood plains are prone to compaction. Furthermore, the analysis of remote sensing and topographic data clearly show significant changes in the land cover and land use, particularly in the northern lagoons and adjacent sabkhas, which are dominated by numerous low subsiding depressions. The areas covered by water logging and ponds are increasing on the expense of agricultural areas, and aquaculture have been practiced instead. The precise estimation of subsidence rates and distribution should be worked out to evaluate probable changes in land cover and land use.
... Earlier interferometric applications in the Nile Delta (Aly et al., 2009(Aly et al., , 2012Becker & Sultan, 2009;Poscolieri et al., 2011) had limited spatial coverage and/or used a small number of scenes (5 to 14 scenes; Aly et al., 2012). To the best of our knowledge, this work is the first of its kind in extracting deformational patterns across the entire length and width of a river delta using radar interferometric techniques. ...
We applied Persistent scatterer interferometry (PSInSAR) to assess land deformation (subsidence and uplift) across the entire Nile delta and its surroundings and to identify possible causes of the observed deformation. For the purpose of the present study, 100 Envisat Advanced Synthetic Aperture Radar (ASAR; level 0) scenes that were acquired along four tracks and covering a time span of seven years (2004 to 2010) were used. The scenes extend from the Mediterranean coast in the north to Cairo city in the south. These scenes were focused using Repeat Orbit Interferometry PACkage (ROI_PAC) software and the subsequent PSI processing was done using the Stanford Method for Persistent Scatterers (StaMPS) method. A low coherence threshold (0.2) was used to decrease the impact of vegetation-related poor coherence and decorrelation of the scenes over the investigated time span. Subsidence was observed over: (1) the Demietta Nile River branch (3 to 14 mm/yr) where it intersects the Mediterranean coastline, (2) thick (~ 40 m) Holocene sediments in lake Manzala (up to 9 mm/yr), (3) reclaimed desert areas (west of Nile Delta; up to 12 mm/yr) of high groundwater extraction, (4) along parts of a previously proposed flexure line (up to 10 mm/yr), and (5) along the eastern sections of the Mediterranean coastline (up to 15.7 mm/yr). The city of Alexandria (underlain by carbonate platform) and the terminus of the Rosetta branch of the Nile River seem to experience almost no ground movement (mean subsidence of 0.28 mm/yr and 0.74 mm/yr respectively) while the cities of Ras Elbar and Port Said (underlain by thick Holocene sediment) exhibit the highest subsidence values (up to 14 mm/yr and 8.5 mm/yr respectively). The city of Cairo has also experienced subsidence in limited areas of up to 7.8 mm/yr. High spatial correlation was also observed between the subsiding areas and the Abu Madi incised valley; the largest gas field in the Nile Delta. Most of the area undergoing subsidence in the Nile Delta is related to sediment compaction and/or groundwater extraction, with other factors such as gas extraction and tectonic drivers correlating with smaller areas.
