scholarly journals The 2018 Long Rainy Season in Kenya: Hydrological Changes and Correlated Land Subsidence

2020 ◽  
Vol 12 (9) ◽  
pp. 1390 ◽  
Author(s):  
Ashraf Rateb ◽  
ElSayed Hermas
Keyword(s):  
Land Subsidence ◽  
Rainy Season ◽  
Active Faults ◽  
Wet Season ◽  
Rainfall Events ◽  
Environmental Disasters ◽  
Hydrological Changes ◽  
The Stability ◽  
Sbas Insar ◽  
Scientific Attention

The wettest 2018 long rainy season (March to May (MAM)) resulted in daily intensive rainfall events in East Africa that have seriously affected the environment and economy in many countries. Land subsidence is one of the environmental disasters that has occurred due to the long rainy season in Kenya for many years. However, it has received limited scientific attention. In this paper, we incorporate hydrological (soil moisture active–passive (SMAP) and loading models) and geodetic data (global positioning system (GPS) and interferometric synthetic aperture radar (InSAR)) to study hydrological changes and their associated subsidence potential in Kenya. Results show that widespread subsidence of more than 20 mm was associated with the MAM season in Kenya during 2018, based on SBAS InSAR measurements. The high values of land subsidence were well correlated with the areas of intense flooding during the MAM season. The widespread subsidence during the wet season has implications for the stability of the earth’s surface during the season rather than creating the possibility of potential stresses along active faults. These stresses may trigger seismicity that is expected to pose risks to urban features. The results of the current study can help governmental authorities to adopt proper urban planning that avoids or minimizes the risks of land subsidence in the areas of sinkholes.

scholarly journals Application of Sentinel-1 and-2 Images in Measuring the Deformation of Kuh-e-Namak (Dashti) Namakier, Iran

2021 ◽  
Vol 13 (4) ◽  
pp. 785
Author(s):  
Sen Zhang ◽  
Qigang Jiang ◽  
Chao Shi ◽  
Xitong Xu ◽  
Yundi Gong ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Rock Salt ◽  
Rainy Season ◽  
Surface Deformation ◽  
Meteorological Data ◽  
Dry Season ◽  
Synthetic Aperture ◽  
Advantages And Disadvantages ◽  
Sbas Insar ◽  
Aperture Radar

Kuh-e-Namak (Dashti) namakier is one of the most active salt diapirs along the Zagros fold–thrust belt in Iran. Its surface deformation should be measured to estimate its long-term kinematics. Ten Sentinel-2 optical images acquired between October 2016 and December 2019 were processed by using Co-Registration of Optically Sensed Images and Correlation (COSI-Corr) method. Forty-seven Sentinel-1 ascending Synthetic Aperture Radar (SAR) images acquired between April 2017 and December 2019 were processed by using Small Baseline Subset Synthetic Aperture Radar Interferometry (SBAS-InSAR) method. The deformation of Kuh-e-Namak (Dashti) namakier was measured using both methods. Then, meteorological data were utilized to explore the relationship between the kinematics of the namakier and weather conditions and differences in macrodeformation behavior of various rock salt types. The advantages and disadvantages of COSI-Corr and SBAS-InSAR methods in measuring the deformation of the namakier were compared. The results show that: (1) The flank subsides in the dry season and uplifts in the rainy season, whereas the dome subsides in the rainy season and uplifts in the dry season. Under extreme rainfall conditions, the namakier experiences permanent plastic deformation. (2) The “dirty” rock salt of the namakier is more prone to flow than the “clean” rock salt in terms of macrodeformation behavior. (3) In the exploration of the kinematics of the namakier via the two methods, COSI-Corr is superior to SBAS-InSAR on a spatial scale, but the latter is superior to the former on a time scale.

scholarly journals Status Update on Bioelectrochemical Systems: Prospects for Carbon Electrode Design and Scale-Up

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 278
Author(s):  
Katharina Herkendell
Keyword(s):  
Gradual Increase ◽  
Scale Up ◽  
Value Added ◽  
Biofuel Cells ◽  
Carbon Electrode ◽  
Electrode Design ◽  
Bioelectrochemical Systems ◽  
Electrode Assemblies ◽  
The Stability ◽  
Scientific Attention

Bioelectrochemical systems (BES) employ enzymes, subcellular structures or whole electroactive microorganisms as biocatalysts for energy conversion purposes, such as the electrosynthesis of value-added chemicals and power generation in biofuel cells. From a bioelectrode engineering viewpoint, customizable nanostructured carbonaceous matrices have recently received considerable scientific attention as promising electrode supports due to their unique properties attractive to bioelectronics devices. This review demonstrates the latest advances in the application of nano- and micro-structured carbon electrode assemblies in BES. Specifically, in view of the gradual increase in the commercial applicability of these systems, we aim to address the stability and scalability of different BES designs and to highlight their potential roles in a circular bioeconomy.

scholarly journals Remote Sensing X-Band SAR Data for Land Subsidence and Pavement Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4751 ◽  
Author(s):  
Sadra Karimzadeh ◽  
Masashi Matsuoka
Keyword(s):  
Land Subsidence ◽  
Sar Images ◽  
Nw Iran ◽  
Traffic Jams ◽  
X Band ◽  
Pavement Monitoring ◽  
Negative Impacts ◽  
Small Baseline ◽  
Sbas Insar ◽  
The City

In this study, we monitor pavement and land subsidence in Tabriz city in NW Iran using X-band synthetic aperture radar (SAR) sensor of Cosmo-SkyMed (CSK) satellites (2017–2018). Fifteen CSK images with a revisit interval of ~30 days have been used. Because of traffic jams, usually cars on streets do not allow pure backscattering measurements of pavements. Thus, the major paved areas (e.g., streets, etc.) of the city are extracted from a minimum-based stacking model of high resolution (HR) SAR images. The technique can be used profitably to reduce the negative impacts of the presence of traffic jams and estimate the possible quality of pavement in the HR SAR images in which the results can be compared by in-situ road roughness measurements. In addition, a time series small baseline subset (SBAS) interferometric SAR (InSAR) analysis is applied for the acquired HR CSK images. The SBAS InSAR results show land subsidence in some parts of the city. The mean rate of line-of-sight (LOS) subsidence is 20 mm/year in district two of the city, which was confirmed by field surveying and mean vertical velocity of Sentinel-1 dataset. The SBAS InSAR results also show that 1.4 km2 of buildings and 65 km of pavement are at an immediate risk of land subsidence.

scholarly journals Land deformation associated with exploitation of groundwater in Changzhou City measured by COSMO-SkyMed and Sentinel-1A SAR data

2018 ◽  
Vol 10 (1) ◽  
pp. 678-687 ◽  
Author(s):  
Deliang Chen ◽  
Yanyan Lu ◽  
Dongzhen Jia
Keyword(s):  
Land Subsidence ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
Groundwater Exploration ◽  
River Delta ◽  
Urban Agglomeration ◽  
Land Deformation ◽  
Small Baseline ◽  
Groundwater Rebound ◽  
Sbas Insar

Abstract The Urban Agglomeration in Yangtze River Delta is one of the most important economic and industrial regions in China. The City of Changzhou is one of the most important industrial citys in Yangtze River Delta Urban Agglomeration. Activities here include groundwater exploration. Groundwater overexploitation has contributed to the major land deformation in this city. The severity and magnitude of land deformation over time were investigated in Changzhou City. A Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology, provides a useful tool in measuring urban land deformation. In this study, a time series of COSMO-SkyMed and Sentinel-1A SAR images covering Changzhou City were acquired. SBAS-InSAR imaging technique was used to survey the extent and severity of land deformation associated with the exploitation of groundwater in Changzhou City. Leveling data was used to validate the SBAR-InSAR productions, the error of SBAR-InSAR annual subsidence results was within 2 mm. The results showed that three main land subsidence zones were detected at Xinbei, Tianning and Wujin District. Four subsidence points were selected to analyze the temporal and spatial evolution characteristics of land subsidence. The subsidence rate of P1 to P4 was −2.48 mm/year, −12.78 mm/year, −18.09 mm/year, and −12.69 mm/year respectively. Land subsidence over Changzhou showed a trend of slowing down from 2011 to 2017, especially in Wujin District. SBAR-InSAR derived land deformation that correlates with the water level change in six groundwater stations. Indicated that with groundwater rebound, the land rebound obviously, and the maximum rebound vale reached 9.13 mm.

Temporal partitioning of reproductive activity in a neotropical anuran community

2004 ◽  
Vol 20 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Brigitte Gottsberger ◽  
Edith Gruber
Keyword(s):  
Water Level ◽  
Rainy Season ◽  
Abiotic Factors ◽  
Reproductive Mode ◽  
Reproductive Activity ◽  
Active Species ◽  
South American ◽  
Wet Season ◽  
Breeding Sites ◽  
Calling Activity

The phenology of calling activity and reproduction of a neotropical anuran community in French Guiana was studied during one rainy season. We investigated the correlation between calling activity, rainfall, temperature and water level in two ponds and recorded the occurrence of tadpoles of pond-breeding species. The study site contained 31 calling frog species, which were divided into groups according to reproductive mode. Increased rainfall was associated with increased reproductive activity in all groups, but temporal patterns in calling activity varied significantly between groups. Species with aquatic oviposition exhibited sporadic acoustic activity, aggregating into explosive breeding events following heavy rainfall. Species laying eggs in foam nests had the peak of calling activity at the start of the rainy season. Taxa with embryonic development on vegetation called mainly from middle to late wet season, being the only group which showed a significant correlation of calling with increasing water level. Dendrobatids with terrestrial oviposition and subsequent parental tadpole transportation were continuously active. Species with direct development or with non-feeding larvae were mainly active at the beginning of the rainy season. It is concluded that phenologies of calling activity in South American tropical anuran species are strongly influenced by abiotic factors like rainfall and availability of breeding sites. The temporal limitation of the rainy season forces species to adjust calling and reproductive activity according to their reproductive modes.

scholarly journals Investigation of Sentinel-1 Derived Land Subsidence Using Wavelet Tools And Triple Exponential Smoothing Algorithm In Lagos, Nigeria

2021 ◽  
Author(s):  
Femi Emmanuel Ikuemonisan ◽  
Vitalis Chidi Ozebo ◽  
Olawale Babatunde Olatinsu
Keyword(s):  
Soil Moisture ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Exponential Smoothing ◽  
Future Trend ◽  
Smoothing Algorithm ◽  
Groundwater Abstraction ◽  
Groundwater Level Fluctuations ◽  
History Of ◽  
Sbas Insar

Abstract Lagos has a history of long-term groundwater abstraction that is often compounded by the rising indiscriminate private borehole and water well proliferation. This has resulted in various forms of environmental degradation, including land subsidence. Prediction of the temporal evolution of land subsidence is central to successful land subsidence management. In this study, a triple exponential smoothing algorithm was applied to predict the future trend of land subsidence in Lagos. Land subsidence time series is computed with SBAS-InSAR technique with Sentinel-1 acquisitions from 2015 to 2019. Besides, Matlab wavelet tool was implemented to investigate the periodicity within land displacement signal components and to understand the relationship between the observed land subsidence, and groundwater level change and that of soil moisture. Results show that land subsidence in the LOS direction varied approximately between –94 and 15 mm/year. According to the wavelet-based analysis result, land subsidence in Lagos is partly influenced by both groundwater level fluctuations and soil moisture variability. Evaluation of the proposed model indicates good accuracy, with the highest residual of approximately 8%. We then used the model to predict land subsidence between the years 2020 and 2023. The result showed that by the end of 2023 the maximum subsidence would reach 958 mm which is approximately 23% increase.

scholarly journals Ongoing research on the pumping-induced land deformation in the Aguascalientes Valley: an analysis of the recent data of vertical deformation, groundwater level variations and local seismicity

2020 ◽  
Vol 382 ◽  
pp. 99-102
Author(s):  
Martin Hernandez-Marin ◽  
Ruben Esquivel-Ramirez ◽  
Mario Eduardo Zermeño-De-Leon ◽  
Lilia Guerrero-Martinez ◽  
Jesus Pacheco-Martinez ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Close Association ◽  
Active Faults ◽  
Vertical Deformation ◽  
Ongoing Research ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Critical Information ◽  
Aguascalientes Valley ◽  
Low Magnitude

Abstract. In the Aguascalientes valley, middle Mexico, the demand of groundwater from the local aquifer system was suddenly increased after the late 1970s. Since then, several related problems have been occurring or become critical such as land subsidence, ground fissuring, and low-magnitude earthquakes. The most recent data of vertical deformation from PSInSAR, groundwater levels, and earthquakes, has provided critical information regarding the relationship amongst all these processes. In particular, that related to land subsidence, earth fissuring and seismicity. Regarding this, more satellite imagery and data from GPS stations are being revised as a possibility of a more generalized vertical deformation derived with low-magnitude seismicity. A particular seismic event recorded on 6 April 2019 has revealed critical information on the close association between vertical displacements occurred in active faults and low-magnitude seismic events.

scholarly journals Diurnal, Seasonal and Annual Variation of Microwave Radio Refractivity Gradient over Akure, South West Nigeria

2019 ◽  
pp. 1-11
Author(s):  
Adekunle Titus Adediji ◽  
Joseph Babatunde Dada ◽  
Moses Oludare Ajewole
Keyword(s):  
Rainy Season ◽  
Annual Variation ◽  
Ground Surface ◽  
Local Effect ◽  
Dry Season ◽  
Radio Link ◽  
Wet Season ◽  
Annual Variations ◽  
Microwave Radio

In this study, four years in-situ measurements of atmospheric parameters (pressure, temperature and relative humidity) were carried out. The measurement was by placing an automatic weather station at five different heights: ground surface, 50, 100, 150 and 200 m respectively on a 220 m Nigeria Television Authority TV tower in Akure, South Western Nigeria. The four years Data collected (January 2007 to December 2009 and January to December 2011) were used to compute radio refractivity and its gradient. The local effect of a location/ region cannot but looked into when designing effective radio link, hence the diurnal, seasonal and annual variations of the radio refractivity gradient were studied. Results showed that refractivity gradient steadily increases inthe hour of 8:30 and 9:30 to 18:00 during dry season throughout the years investigated, and decreases two hours in the rainy season than the dry season. The record shows that at 50 m altitude, the maximum and minimum values are 158 N-unit/km around 14:30 and - 286 N-unit/km around 13:30 to 14:00 hrs, LT during the dry and rainy season respectively. Seasonally, refractivity gradient is steeper with greater variability in the dry season months than in the wet season months.

Predictive estimates of subsidence of the earth’s surface during the development of the Yamburgskoye oil and gas condensate field

2021 ◽  
pp. 9-22
Author(s):  
Yu. V. Vasiliev ◽  
M. S. Mimeev ◽  
D. A. Misyurev
Keyword(s):  
Oil And Gas ◽  
Active Faults ◽  
Physical And Mechanical Properties ◽  
Deformation Model ◽  
Reservoir Pressure ◽  
Gas Reservoirs ◽  
Field Development ◽  
Geodynamic Processes ◽  
Deformation Processes ◽  
The Stability

The production of hydrocarbons is associated with a change in the physical and mechanical properties of oil and gas reservoirs under the influence of rock and reservoir pressures. Deformation of the reservoir due to a drop in reservoir pressure leads to the formation of various natural and man-made geodynamic and geomechanical phenomena, one of which is the formation of a subsidence trough of the earth's surface, which leads to a violation of the stability of field technological objects.In order to ensure geodynamic safety, a set of works is used, which includes analysis of geological and field indicators and geological and tectonic models of the field, interpretation of aerospace photographs, identification of active faults, construction of a predictive model of subsidence of the earth's surface of the field with identification of zones of geodynamic risk.This work was carried out to assess the predicted parameters of rock displacement processes during field development; even insignificant disturbances in the operation of technological equipment caused by deformation processes can cause significant damage.Prediction of rock displacements is possible only on the basis of a reservoir deformation model that adequately reflects the geomechanical and geodynamic processes occurring in the subsoil. The article presents a model of reservoir deformation with a drop in reservoir pressure, describes its numerical implementation, and performs calculations of schemes for typical development conditions.

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