Ground Deformation and Its Causes in Abbottabad City, Pakistan from Sentinel-1A Data and MT-InSAR

Land subsidence, as one of the engineering geological problems in the world, is generally caused by compression of unconsolidated strata due to natural or anthropogenic activities. We employed interferometric point target analysis (IPTA) as a multi-temporal interferometric synthetic aperture radar (MT-InSAR) technique on ascending and descending Sentinel-1A the terrain observation with progressive scans SAR (TOPSAR) images acquired between January 2015 and December 2018 to analyze the spatio-temporal distribution and cause of subsidence in Abbottabad City of Pakistan. The line of sight (LOS) average deformation velocities along ascending and descending orbits were decomposed into vertical velocity fields and compared with geological data, ground water pumping schemes, and precipitation data. The decomposed and averaged vertical velocity results showed significant subsidence in most of the urban areas in the city. The most severe subsidence was observed close to old Karakorum highway, where the subsidence rate varied up to −6.5 cm/year. The subsidence bowl profiles along W–E and S–N transects showed a relationship with the locations of some water pumping stations. The monitored LOS time series histories along an ascending orbit showed a close correlation with the rainfall during the investigation period. Comparative analysis of this uneven prominent subsidence with geological and precipitation data reflected that the subsidence in the Abbottabad city was mainly related to anthropogenic activities, overexploitation of water, and consolidation of soil layer. The study represents the first ever evidence of land subsidence and its causes in the region that will support the local government as well as decision and policy makers for better planning to overcome problems of overflowing drains, sewage system, littered roads/streets, and sinking land in the city.

Download Full-text

Simulation of the Cooking Organic Aerosol Concentration Variability in an Urban Area

10.5194/egusphere-egu21-10090 ◽

2021 ◽

Author(s):

Evangelia Siouti ◽

Ksakousti Skyllakou ◽

Ioannis Kioutsioukis ◽

Giancarlo Ciarelli ◽

Spyros N. Pandis

Keyword(s):

Urban Area ◽

Urban Areas ◽

Temporal Distribution ◽

Late Summer ◽

Field Studies ◽

Organic Aerosol ◽

Basis Set ◽

Cooking Times ◽

The City ◽

Lunch Time

Cooking operations can be an important fine PM source for urban areas. Cooking emissions are a source of pollution that has been often ignored and are not included or are seriously underestimated in urban emission inventories. However, several field studies in cities all over Europe suggest that cooking organic aerosol (COA) can be an important component of the total organic PM. In this study we propose and evaluate a methodology for the simulation of the COA concentration and its variability in space and time in an urban area. The city of Patras, the third biggest in Greece is used for this first application for a typical late summer period. The spatial distribution of COA emissions is based on the exact location of restaurants and grills, while the emissions on the meat consumption in Greece. We estimated COA emissions of 150 kg d-1 that corresponds to 0.6 g d-1 per person. The temporal distribution of COA was based on the known cooking times and the results of the past field studies in the area. Half of the daily COA is emitted during dinner time (21:00-0:00 LT), while approximately 25% during lunch time (13:00-16:00 LT). The COA is simulated using the Volatility Basis Set with a volatility distribution measured in the laboratory and is treated as semivolatile and reactive. The maximum average COA concentration during the simulation period is predicted to be 1.3 &#956;g m-3 in a mainly pedestrian area with a high density of restaurants. Peak hourly COA concentrations in this area exceed 10 &#956;g m-3 during several nights. The local production of secondary COA is predicted to be slow and it represents just a few percent of the total COA.&#160;

Download Full-text

Tracking Lead in Environmental Media in the City of Onitsha, Southeast Nigeria

Journal of Health and Pollution ◽

10.5696/2156-9614-9.24.191202 ◽

2019 ◽

Vol 9 (24) ◽

pp. 191202

Author(s):

Timothy Iyobosa Asowata ◽

Akinade Shadrach Olatunji

Keyword(s):

Land Use ◽

Urban Areas ◽

Anthropogenic Activities ◽

Emission Spectrometry ◽

Pb Isotope ◽

Land Use Patterns ◽

Environmental Media ◽

Waste Dumps ◽

Soils And Sediments ◽

The City

Background. The enrichment of lead (Pb) in a rapidly expanding urban environment is largely caused by industrial and anthropogenic activities. However, very few studies have come from sub-Sahara Africa as a whole, in spite of the increased rate of population, industrialization and urbanization in this region. The city of Onitsha is the commercial heartland of southeast Nigeria. Objectives. To determine the concentration of Pb in soils and sediments in Onitsha and the surrounding area and to identify the possible sources of Pb content in the environmental media. Methods. One hundred and sixty-two (162) samples (120 top and subsoils, and 42 stream and side drain sediments) were collected from the city of Onitsha, Nigeria to determine Pb concentrations, identify the main sources of Pb in this region, and determine its fate in soil and sediments using Pb isotopes. Thirty (30) 15 g clay fractions of soil and sediment samples, and a sample each of galena (from the Lower Benue Trough), coal and soot from vehicle exhaust and battery cells were collected from the city and analyzed for lead isotopes (Pb204, Pb206, Pb207 and Pb208) using ultra-trace inductively coupled plasma emission spectrometry. Results. The distribution and concentration of Pb in the soil of Onitsha was observed to be influenced by land use patterns with very elevated concentrations of Pb observed for mechanic and metal workshop samples (1444.3, 1067.5, 1048.1, 1730.5 and 580.5 ppm); active waste dump samples (448.4 and 311.9 ppm); and farmland and garden samples (366.2 ppm). The concentration of Pb in the sediments also showed varying elevated concentrations across locations, ranging from 45.7–540.1 ppm. A comparison with the control samples revealed that the Pb concentrations measured in the environmental media were several folds higher than that of the control. The Pb isotope analysis indicated that most of the Pb in environmental media was anthropogenic in origin and had been predominantly contributed by unsustainable environmental practices such as indiscriminate waste dumps, hydrocarbonbased products emissions, by-products from mechanical workshops that have been haphazardly constructed in the city, and industrial plants located within urban areas. Conclusions. The relatively higher concentrations of Pb in soils and sediments were found to be influenced by land use, as also observed in the Pb isotope readings, which will, over time, adversely affect environmental media and biota. Competing Interests. The authors declare no competing financial interests.

Download Full-text

Spatial and temporal distributions of total and methyl mercury in precipitation in core urban areas, Chongqing, China

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-9417-2012 ◽

2012 ◽

Vol 12 (20) ◽

pp. 9417-9426 ◽

Cited By ~ 27

Author(s):

Y. M. Wang ◽

D. Y. Wang ◽

B. Meng ◽

Y. L. Peng ◽

L. Zhao ◽

...

Keyword(s):

Urban Areas ◽

Methyl Mercury ◽

Total Mercury ◽

Temporal Distribution ◽

Distribution Patterns ◽

Mean Value ◽

Motor Vehicles ◽

Volume Weight ◽

Spatial And Temporal Distributions ◽

The City

Abstract. The spatial and temporal distribution patterns of mercury (Hg) in precipitation were investigated in the core urban areas of Chongqing, China. During the period from July 2010 to June 2011, total mercury (THg) and methyl mercury (MeHg) concentrations in precipitation were analysed from three sampling sites. Our results suggested that the volume-weight mean THg and MeHg concentrations in precipitation were 30.67 ng l−1 and 0.31 ng l−1, respectively. The proportion of MeHg in THg ranged from 0.1% to 7.6% with a mean value of 1.3%. THg and MeHg concentrations showed seasonal variations, while the highest THg value was measured in winter. Contrarily, the highest MeHg concentration was observed in autumn. Additionally, a geographically gradual decline of THg concentration in precipitation was observed from the downtown to the suburb, then to the controlled site in the city. 5 mm rainfall might be a threshold for the full wash-out capability. Rainfall above 5 mm may have a diluting effect for the concentrations of THg. Moreover, the current research implies that the coal combustion and motor vehicles could be the dominant sources for Hg in the precipitation.

Download Full-text

Analysis of Clay-Induced Land Subsidence in Uppsala City Using Sentinel-1 SAR Data and Precise Leveling

Remote Sensing ◽

10.3390/rs11232764 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2764 ◽

Cited By ~ 2

Author(s):

Jonas Fryksten ◽

Faramarz Nilfouroushan

Keyword(s):

Land Subsidence ◽

Ground Deformation ◽

Ground Surface ◽

Urban Infrastructure ◽

Data Sets ◽

Interferometric Synthetic Aperture Radar ◽

Persistent Scatterer Interferometry ◽

New Methods ◽

Persistent Scatterer ◽

The City

Land subsidence and its subsequent hazardous effects on buildings and urban infrastructure are important issues in many cities around the world. The city of Uppsala in Sweden is undergoing significant subsidence in areas that are located on clay. Underlying clay units in parts of Uppsala act as mechanically weak layers, which for instance, cause sinking of the ground surface and tilting buildings. Interferometric Synthetic Aperture Radar (InSAR) has given rise to new methods of measuring movements on earth surface with a precision of a few mm. In this study, a Persistent Scatterer Interferometry (PSI) analysis was performed to map the ongoing ground deformation in Uppsala. The subsidence rate measured with PSI was validated with precise leveling data at different locations. Two ascending and descending data sets were analyzed using SARPROZ software, with Sentinel-1 data from the period March 2015 to April 2019. After the PSI analyses, comparative Permanent Scatterer (PS) points and metal pegs (measured with precise leveling) were identified creating validation pairs. According to the PSI analyses, Uppsala was undergoing significant subsidence in some areas, with an annual rate of about 6 mm/year in the line-of-sight direction. Interestingly, the areas of great deformation were exclusively found on postglacial clay.

Download Full-text

A decade-long silent ground subsidence hazard culminating in a metropolitan disaster in Maceió, Brazil

Scientific Reports ◽

10.1038/s41598-021-87033-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Magdalena Vassileva ◽

Djamil Al-Halbouni ◽

Mahdi Motagh ◽

Thomas R. Walter ◽

Torsten Dahm ◽

...

Keyword(s):

Urban Areas ◽

Ground Deformation ◽

Anthropogenic Activities ◽

Surface Displacement ◽

Ground Subsidence ◽

Anthropogenic Processes ◽

Precipitation Events

AbstractGround subsidence caused by natural or anthropogenic processes affects major urban areas worldwide. Sinkhole formation and infrastructure fractures have intensified in the federal capital of Maceió (Alagoas, Brazil) since early 2018, forcing authorities to relocate affected residents and place buildings under demolition. In this study, we present a 16-year history (2004–2020) of surface displacement, which shows precursory deformations in 2004–2005, reaching a maximum cumulative subsidence of approximately 200 cm near the Mundaú Lagoon coast in November 2020. By integrating the displacement observations with numerical source modelling, we suggest that extensive subsidence can be primarily associated with the removal of localized, deep-seated material at the location and depth where salt is mined. We discuss the accelerating subsidence rates, influence of severe precipitation events on the aforementioned geological instability, and related hazards. This study suggests that feedback destabilization mechanisms may arise in evaporite systems due to anthropogenic activities, fostering enhanced and complex superficial ground deformation.

Download Full-text

Land subsidence caused by groundwater exploitation in Quetta and surrounding region, Pakistan

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-382-595-2020 ◽

2020 ◽

Vol 382 ◽

pp. 595-607 ◽

Cited By ~ 1

Author(s):

Najeebullah Kakar ◽

Din Muhammad Kakar ◽

Sadia Barrech

Keyword(s):

Ground Water ◽

Land Subsidence ◽

Urban Areas ◽

Anthropogenic Activities ◽

Developed Countries ◽

Water Shortages ◽

Groundwater Exploitation ◽

Surrounding Areas ◽

Quetta Valley ◽

Water Quality And Quantity

Abstract. Land subsidence is effecting several metropolis in the developing as well as developed countries around the world such as Nagoya (Japan), Shanghai (China), Venice (Italy) and San Joaquin valley (United States). This phenomenon is attributed to natural as well as anthropogenic activities that include extensive groundwater withdrawals. Quetta which is facing similar subsidence phenomenon is the largest city of Balochistan province in Pakistan. This valley is mostly dry and ground water is the major source for domestic and agricultural consumption. The unplanned use of ground water resources has led to the deterioration of water quality and quantity in the Quetta valley. Water shortages in the region was further aggravated by the drought during (1998–2004) that affected the area forcing people to migrate from rural to urban areas. Refugees from the war torn neighboring Afghanistan also contributed to rapid increase in population of Quetta valley that has increased from 0.26 million in 1975 to 3.0 million in 2016. The objective of this study was to measure the land subsidence in Quetta valley and identify the effects of groundwater withdrawals on land subsidence. To achieve this goal, data from five Global Positioning System (GPS) stations in Quetta were acquired and processed. Furthermore the groundwater decline data from 41 observation wells during 2010 to 2015 were calculated and compared with the land deformation. The results of the GPS readings revealed that the land of Quetta valley is subsiding from 30 mm yr−1 on the flanks to 120 mm yr−1 in the central part. 1.5–5.0 m yr−1 of groundwater level drop was recorded in the area where the rate of subsidence is highest. Whereas 9–10 cm of subsidence was recorded in the surrounding areas of Quetta where agriculture and settlements are high. The surrounding areas include Kuchlak, Mastung, Pishin, Gulistan and Hurumzai districts. These results were acquired using InSAR imagery collected from October 2014 to march 2019. So the extensive groundwater withdrawals in Quetta valley and surrounding areas is considered to be the driving force behind land subsidence.

Download Full-text

Analysis of Clay-Induced Land Subsidence in Uppsala City Using Sentinel-1 SAR Data and Precise Leveling

10.5194/egusphere-egu2020-7322 ◽

2020 ◽

Author(s):

Faramarz Nilfouroushan ◽

Jonas Fryksten

Keyword(s):

Land Subsidence ◽

Ground Deformation ◽

Ground Surface ◽

Urban Infrastructure ◽

Annual Rate ◽

Line Of Sight ◽

Data Sets ◽

Persistent Scatterer ◽

The World ◽

The City

Land subsidence and its subsequent hazardous effects on buildings and urban infrastructure are important issues in many cities around the world. The city of Uppsala in Sweden is undergoing significant subsidence in areas that are located on clay. Underlying clay units in parts of Uppsala act as mechanically weak layers, which for instance, cause sinking of the ground surface and tilting buildings. In this study, a Persistent Scatterer InSAR (PSI) analysis was performed to map the ongoing ground deformation in Uppsala. The subsidence rate measured with PSI was validated with precise leveling data at different locations. Two ascending and descending data sets were analyzed using SARPROZ software, with Sentinel-1 data from the period March 2015 to April 2019. After the PSI analyses, comparative permanent scatterer (PS) points and metal pegs (measured with precise leveling) were identified creating validation pairs. According to the PSI analyses, Uppsala was undergoing significant subsidence in some areas, with an annual rate of about 6 mm/year in the line-of-sight direction. Interestingly, the areas of great deformation were exclusively found on postglacial clay.

Download Full-text

Multi-Frequency and Multi-Temporal InSAR Analysis for Monitoring Land Subsidence, Aswan City, Egypt

10.5194/egusphere-egu21-292 ◽

2021 ◽

Author(s):

Noha Medhat ◽

Masa-yuki Yamamoto ◽

Gad El-Qady

Keyword(s):

Land Subsidence ◽

Urban Areas ◽

Ground Deformation ◽

Anthropogenic Impacts ◽

Ground Truth ◽

Subsurface Water ◽

Ground Truth Data ◽

Time Period ◽

Management Plans ◽

Multi Temporal

Land deformation due to natural and anthropogenic impacts considered to be one of the challenging environmental problems in the Aswan area located in the southern part of Egypt. Specifically, we applied multi-sensor analysis in order to record the slow rate of subsidence with a high spatial resolution of COSMO-SkyMed (X-band) and Sentinel-1 TOPSAR (C-band) scenes. We proposed multi-temporal DInSAR data analysis by means of ascending and descending orbit tracks during the recent time period of 2012-2017. The stacked DInSAR results reported the occurrence of land subsidence of active urban areas. A strong correlation between the ground truth data, ground leveling, and the estimated Line of Sight (LOS) displacement time series values are reached, assuming the ground deformation controlled by seasonal surface water loading, lithological units, and subsurface water activity. The detection of short-term displacement highlights the priority of groundwater management plans in the affected urban areas.

Download Full-text

Ground deformation detection of the greater area of Thessaloniki (Northern Greece) using radar interferometry techniques

Natural Hazards and Earth System Science ◽

10.5194/nhess-8-779-2008 ◽

2008 ◽

Vol 8 (4) ◽

pp. 779-788 ◽

Cited By ~ 30

Author(s):

D. Raucoules ◽

I. Parcharidis ◽

D. Feurer ◽

F. Novalli ◽

A. Ferretti ◽

...

Keyword(s):

Surface Deformation ◽

Ground Deformation ◽

Anthropogenic Activities ◽

Ground Surface ◽

Underground Water ◽

Radar Interferometry ◽

Northern Greece ◽

Ground Conditions ◽

Permanent Scatterers ◽

The City

Abstract. In the present study SAR interferometric techniques (stacking of conventional interferograms and Permanent Scatterers), using images from satellites ERS-1 and 2, have been applied to the region of Thessaloniki (northern Greece). The period covered by the images is 1992–2000. Both techniques gave good quantitative and qualitative results. The interferometric products were used to study ground surface deformation phenomena that could be related to the local tectonic context, the exploitation of underground water and sediments compaction. The city of Thessaloniki shows relatively stable ground conditions. Subsidence in four locations, mainly in the area surrounding the city of Thessaloniki, has been detected and assessed. Two of the sites (Sindos-Kalochori and Langadhas) were already known from previous studies as subsiding areas, using ground base measurements. On the contrary the other two sites in the northern suburbs of Thessaloniki (Oreokastro) and in the south-east (airport area) were unknown as areas of subsidence. A further investigation based on fieldwork is needed in these two areas. Finally, an attempt to interpret the observed deformation, according to the geological regime of the area and its anthropogenic activities, has been carried out.

Download Full-text

Numerical modelling of land subsidence related to groundwater withdrawal in the Firenze-Prato-Pistoia basin (central Italy)

Hydrogeology Journal ◽

10.1007/s10040-020-02255-2 ◽

2020 ◽

Author(s):

Mattia Ceccatelli ◽

Matteo Del Soldato ◽

Lorenzo Solari ◽

Riccardo Fanti ◽

Gaddo Mannori ◽

...

Keyword(s):

Land Subsidence ◽

Climate Model ◽

Ground Deformation ◽

Global Climate Model ◽

Central Italy ◽

Groundwater Withdrawal ◽

Integrated Modelling ◽

Groundwater Extraction ◽

Ground Displacement ◽

The City

Abstract The Tuscany region of Italy is widely affected by subsidence, landslides and floods, which severely impact buildings and infrastructure. In particular, Firenze-Prato-Pistoia basin has a long experience of ground deformation related to groundwater withdrawal. European remote-sensing satellite (ERS) data collected since 1992 have revealed the presence of several subsiding areas in the basin such as the south-eastern portion of the city of Pistoia. Sentinel-1 persistent scatterer interferometry (PSI) measurements for 2015–2018 confirmed the long-term subsidence of this area, associated with intense horticulture (plant nurseries). At the same time, Sentinel-1 data revealed the unexpected movement of Pistoia historic center, which has always been considered stable in the past. To identify the complex relationship between aquifer conditions and ground displacement, a hydrogeologic model of the Pistoia aquifers was developed, applying an integrated modelling procedure. Hydrodynamic-parameter distributions, calibrated and validated by means of Sentinel-1 PSI measurements, suggest that subsidence in Pistoia area is probably related with the combined impacts of groundwater extraction and highly compressible aquitards. To evaluate the potential evolution of ground displacement, numerical simulations were extended until 2050, using regional and global climate model data, analyzing three different pumping-rate scenarios. This led to the development of several subsidence hazard maps of the city of Pistoia that display the influence of groundwater extraction in controlling land subsidence in the area. This study emphasizes the importance of developing proper groundwater management policies, especially in alluvial aquifers made of fine compressible sediments, in order to sustainably utilize underground freshwater resources and to avoid related side effects.

Download Full-text