Electrical-resistivity survey is a widely employed invasive method in groundwater exploration studies, especially in hard rock terrain. Hence, this method is adopted in this study to identify suitable sites for groundwater exploration through hydro-geological characteristics. A total of 120 vertical electrical soundings (VES) were conceded by applying Schlumberger arrangement and analyzed within IPI2win software version 2008. From the interpretation, the majority of the combinations of curve types are obtained as follows: HA>H>KH>QH>A>AA>AK=HKA=QQ. Three to four layers were found, such as recent deposits (clay), weathered zone, semi-weathered zone/fractured, and basement rock which were identified. In addition, the Dar-Zarrouk (D-Z) parameters, namely, longitudinal conductance as “S”, total transverse unit resistance as “T,” longitudinal resistivity as “ρl,” transverse resistivity as “ρt,” and coefficient of anisotropy as “λ,” were performed to know resistivity regime of the aquifers. These parameters play an important role in knowing the occurrence and distribution of aquifers. The “S” and “T” parameters of D-Z and their distinctiveness offer information about the presence of groundwater in large granitic aquifer systems. Decision-makers, government agencies, and farmers could find these findings to be useful.

Relative permeability is one of the dynamic properties in reservoir fluid flow that is essential in characterizing the simultaneous flow of fluids in the reservoir and plays a vital role in reservoir production studies and EOR processes. The relative permeability ratio is used to describe better and employ relative permeability data presented in individual curves. The simultaneous flow of reservoir fluids is well described by the coefficients a and b, which are obtained from the linear part of the ratio curve. These coefficients, considered critical parameters of the relative permeability curve, are complex. Factors and concepts affecting the a and b coeffecients are not well defined. The corresponding values of a and b were obtained from the experimental relative permeability data for carbonate rocks. Factors affecting these coefficients were studied and evaluated in this paper. The results indicate that coefficient b is mainly affected by the pore size heterogeneity and fluid saturation distribution. In contrast, the coefficient a is influenced by residual water saturation and fine pores. Another notable result of this study was using experimental relationships to determine the relative permeability parameters, including coefficients a and b and residual saturation values using mercury injection data.

In order to determine the thickness of the crust, this study offers the coherently stacked P-wave receiver functions and Bouguer anomaly mapping of the Western Himalayas (longitude 71–74E and latitude 31–34N). Gravity data is taken from Topex, which is in the public domain and is open for research, whereas the information utilized for the P-wave receiver function is taken from the local seismic network of Pakistan. By coherently stacking the Ps, PpPs, PpSs + PsPs phases of 15 seismic stations, it is possible to determine the crust thickness and average crust Vp/Vs ratio at each station in the network. The events selected for this study were those with magnitudes ≥ 6 and epicentral distances of 300 to 950. Data were gathered from 2012 to 2019. The Moho depth beneath the broadband seismic stations employed for the study varies significantly. Moho depths range from 36 km in the south to an average of 46 km in the middle and 52 km in the study area’s northernmost seismic station. In the research area, the crust generally dips from south to north. Residual calculation of Bouguer anomaly data was also performed in order to validate this inferred argument of moho-depth variation from the P-Wave receiver function. These gravity residuals from the investigated area’s anomalous data ranging from − 89 to 193 mGal have shown a promising association and supported the theory of crustal dipping put forth by the P-wave function from the seismic network. The tendency supports the theory that the collision of the Indian and Asian plates is what is causing the thickening and shortening of the crust.

An evaluation was done to better understand the utilization of empirical formulas and discrimination diagrams in the determination of sediment origin, frequently in Central Africa. For this purpose, a database was established for geochemical data (major and trace elements) collected from present-day environments or Mesozoic deposits with variable environments and source geologies from two countries of Central Africa (Cameroon and Nigeria). The plotting of modern sediments and ancient rocks in the same diagrams has revealed the low impact of diagenetic processes on the chemical compositions. The results suggest that the proximal provenance proposed by several authors that used empirical formulas and discriminant diagrams to infer the origin of sediments are not always appropriate for all types of sediments. This study shows that chemical index of weathering (CIW) and plagioclase index of alteration (PIA) derive from chemical index of alteration (CIA). It is therefore recommended that they should be used with caution while taking into account the regional geological settings, the location of source area, the paleoweathering of source rocks, and hydraulic-sorting effects. In addition, it is also recommended to use other diagrams such mobile alkaline earth metals versus chemical index of alteration (CIA).

This work delivers comprehensive information on the statistical metrics of sea level in Port Said Harbor, which can be used for the mitigation plans and protection measures in its vicinity. The study used hourly sea level data extended over 10 years from January 2002 to December 2011. A comprehensive descriptive statistical analysis of sea level monthly variations was introduced. The T_Tide package was used to obtain the astronomical constituents, which are in turn used to calculate the form factor to specify the tidal cycle in the Harbor, and to obtain the main water level characteristics. The meteorological factor was calculated by subtracting the tidal elevation from the recorded sea level. The impact of the meteorological factors on the observed sea level fluctuations was more obvious in winter than in summer. The effect of the meteorological conditions on the observed possible largest sea level range was \({~}^{1}\!\left/ \!{~}_{3}\right.\) that of the tidal impact. No extreme sea level year, considered when the annual mean deviates from the regression line by more than twice the standard deviation, appeared during the decade of investigation. The return periods and the design lifetime risk were calculated. The highest probabilities of occurrence were concentrated in the levels between 70 and 80 cm, while the lowest were below 5 cm and above 110 cm. The return periods for all water levels ranged between 0.4 and 4.5 years. The coastal structures in the vicinity of the Harbor may have a short lifetime of only 50 years for its most pronounced level (75 cm). It is recommended to consider the present results upon designing mitigation plans and constructions within Port Said Harbor territory.

The levelling network is arranged in separate lines that together form levelling polygons. When determining the vertical movements of the Earth’s surface based on the results of levelling measurements, the results are obtained only at the location of the geodetic network. During the compilation of the vertical movements of the Earth’s surface, a significant part of the studied area lacks measurement-based results, and the movement values are obtained by interpolation. Therefore, measurements of movement obtained inside levelling polygons are relatively inaccurate, and active centres of movement are concentrated only on the levelling lines. The present article introduces a methodology that allows determining the vertical surface movements in the entire area. The methodology holistically employs statistical methods, geoindexes, and levelling measurement data. Movement values are calculated for points evenly spaced throughout the entire area. The vertical movement map compiled based on this methodology is not subject to such significant influence by the interpretations of the interpolation algorithm, moreover, it avoids the concentration of movements in the levelling lines. During the study, three maps of vertical movements of the Earth’s surface are compiled: one is created on the basis of the levelling results, and two other maps — using the proposed methodology. The comparison of the maps reveals that the main rising/sinking tendencies of the Earth’s surface match, and simultaneously the concentration of movements in geodetic points is avoided.

Groundwater is an important source of drinking water and irrigation. However, due to increased anthropogenic activities, its quantity and quality are gradually deteriorating over time. The current paper focuses on the evaluation of groundwater quality and its variability for drinking purpose in Gurugram district of Haryana. Geographical Information System based groundwater quality index (GWQI) is a cost-effective tool for the assessment of groundwater quality and its variability. Nine water quality parameters, i.e., sodium, potassium, magnesium, calcium, chloride, sulfate, nitrate, fluoride, and total dissolved solvent have been considered for quality assessment of pre-monsoonal season. Two GIS-based groundwater quality index maps GWQI-9 (for all the above mentioned parameters) and GWQI-4 (for the critical parameters whose concentrations exceeded the permissible limit) were produced. Subsequently, correlation analysis and factor analysis were performed to determine the degree of correlation and to identify the principal factor of contamination among all nine water quality parameters, respectively. Interpolated maps, concentration maps, and rank maps were developed for each parameter. Furthermore, the rank map was used to assign weight to each parameter. Based on rank and weight, the final GIS-based GWQI-9 and GWQI-4 were developed. Higher GWQI values reflect higher water quality. Overall, the north-eastern parts of the district have high water quality, while the western and northwestern periphery of Gurugram has low water quality. Except northern and north western region, most of region of Gurugram have poor water quality in terms of GWQI-4. It is possible to conclude that GIS-based GWQI could become a comprehensive approach for assessing surface or groundwater quality.

The empirical GIN (grouting intensity number) method is one of the most popular methods for structural stabilization and is increasingly used in many projects. The concept of this method is to limit the combination of pressure and volume injected to a specific grouting intensity number in order to control the energy induced in the rock fractures and to avoid heaving. In order to ensure the water tightness of the foundation of the Memve’ele hydroelectric dam, the treatment by the GIN method was implemented. The protocol implemented consisted to carry out a veil of injection drilling, consolidation, and control of effective treatment on each geotechnical hazard zone. Thus, 1240 injection boreholes were opened over a total length of 1600 m, i.e.: 613 pre-treatment boreholes and 627 consolidation boreholes. The results of the monitoring tests show that the 0.7 cement grouting treatment contributed to a reduction in crack permeability to less than 5 Lu (Lugeon units), a reduction of over 94%. This confinement of the rock was confirmed by geophysical imagery whose signature at the fractured interval varied after treatment. Geophysical and geohydrological characterization through permeability testing and electrical tomography revealed the existence of highly permeable discontinuity zones (over 90 Lu) below the bedrock surface, up to 15 m wide. Notwithstanding the volume of drilling carried out, the results obtained support the use of the GIN method in the stabilization of foundations of structures in the granite-gneissic basement zone.

To explain the origin of the Carlin-type gold deposit, it is vital to understand their ore-forming chronology. However, the metallogenic age of the deposit remains controversial because of its inadequate traditional dating minerals. Backscattered electron imaging and X-ray elemental mapping of monazite in the Au-rich ore samples obtained from the Laozhaiwan gold deposit in the Golden Triangle region revealed the presence of distinct high-Th cores surrounded by low-Th inclusion-rich rims. The rim of a monazite grain is considered to be formed because of fluid-aided coupled dissolution–reprecipitation via metamorphic reactions during gold mineralization. In this study, hydrothermal monazite formed during the hydrothermal activity of the gold ore was selected as the object of dating, and the metallogenic age of the Carlin-type gold deposit in Laozhaiwan was determined to be 218–230 Ma, indicating Indosinian mineralization. This age was interpreted as the gold mineralization age and correlated with the Re–Os age of arsenopyrite in the Jinya gold deposit, the U–Pb age of rutile, and the 40Ar–39Ar age of sericite in the Zhesang gold deposit. The obtained age data demonstrated that the Indosinian (Triassic) gold mineralization in the Golden Triangle region was related to the progressive closure of the Paleo-Tethys Ocean and the subsequent collision between the South China Craton and Indochina block. The findings show that the metallogenic setting of the Golden Triangle is similar to that of Northeast Vietnam, where mineralization was also related to the closure of the Paleo-Tethys Ocean.

Scientific prediction of TBM tunneling efficiency has important guiding value and significance for long-distance tunnel construction risk and project cost control. A TBM tunneling speed prediction model based on the least squares support vector machine algorithm optimized by the improved particle swarm optimization algorithm is proposed. The standard particle swarm optimization algorithm is improved by using adaptive inertia weight, and the regularization parameters and kernel parameters of LSSVM are optimized based on the improved PSO algorithm. The tunneling speed prediction of TBM is trained by using the tunnel data of No.3 tunnel in Queens, New York and Karagyi-Tehran diversion tunnel in Iran. After the training reaches a certain accuracy, the actual engineering data of TBM construction of long tunnel in Xinjiang are predicted. The results show that the proposed IPSO-LSSVM model has a prediction fitting degree of 0.9776 for TBM tunneling speed and an average absolute error of 1.0771%, which is more accurate than the prediction results of SVR, LSSVM and PSO-LSSVM models. The prediction error does not exceed 1.5% in practical engineering.

Assessment of environmental flow, that has to be maintained along a waterway to keep up health of riverine biological systems, is a key challenge in alleviating impact of establishing hydropower projects especially in mountainous ungauged catchment under limited data conditions. This study addresses the data scarcity issue by prediction of runoff from a Himalayan catchment, India, using HEC-HMS model and then estimating environmental flow based on daily rainfall data of 39 years (1980–2018). The soil conservation service–curve number method is employed for surface runoff estimation that utilizes spatially distributed maps of soil types, drainage, stream order, 4-year land use/land cover (1990, 2000, 2010, and 2020), and hydrologic soil group (HSG). Steep slopes (more than 60%), high annual rainfall (1377 mm), large area under C class of HSG (477.94 km2), and moderate values of curve number (70.51, 70.36, 70.16, and 70.54) revealed high potential for surface runoff generation in the catchment. Predicted runoff depicted a gradually increasing trend during 1980–1995 and decreasing trend during 1995–2008 and 2011–2017. In addition, an abrupt change was observed in annual runoff values in years 1992, 1998, and 2018 when the peak rate of runoff crossed the value of 2000 m3 s−1. The HEC-HMS model is validated by close agreement between peaks and troughs of runoff and rainfall values, and with reasonable values of correlation coefficient (0.57) and coefficient of determination (0.33). The annual values of environmental flow is obtained as 75 and 55 m3 s−1 from the flow duration curves at 70th and 90th percentiles, respectively. Findings of this study are useful for management of flood water in other ungauged mountainous catchment of Himalayan region as well as in other parts of the world under data scarcity conditions.

Ozone and nitrogen pollution of the urban outdoor air in Tehran, a megacity of 10 million inhabitants with heavy urban traffic, strongly affects the health of its citizens. Therefore, monitoring of ozone (O3) and nitrogen (NO2) pollutants is crucial. The aim of this study is to investigate the seasonality of ground-level and the total column O3, the ground-level NO2, and their interactions. For this purpose, in 14 air quality measurement stations of Tehran Air Quality Control Company (AQCC), the OMI/MODIS Aqua products were used for a period of 10 years (2010–2019) as well as the TROPOspheric Monitoring Instrument (TROPOMI) data (2019–2022). The results of the stations analysis show that the monthly mean surface O3 concentration presents a maximum level in June and a minimum in December. The maximum amount of shortwave radiation flux and UV index was also in June and July. The minimum and maximum of the total O3 concentration column are located north of Tehran and southwest of the province, respectively, with a difference of 9DU between the two. Comparison of the total column and surface ozone data shows high concentration during the spring months. It was not possible to determine the overall relationship between nitrogen and ozone at the station scale. However, the total vertical column of the atmosphere and the tropopause height are mainly negatively correlated based on IMO/MODIS Aqua products. Finally, the analysis of TROPOMI data (2019–2022) confirmed the seasonal variability of NO2 and O3 over Iran while identifying correlation areas of O3 and NO2 over Iran, suggesting potential areas of O3 generation such as urban areas, oil/gas refineries, and natural barrier for pollutant dispersion such as mountains.

This work aims to study the tide gauges of the west coast of Africa, from Gibraltar to the Cape of Good Hope. The relative rate of rise (RoR) of the sea levels is computed in every tide gauge satisfying minimum length and quality requirements. This information is supplemented by the satellite global positioning system (GPS) measurement of the subsidence of the land nearby the tide gauge to compute the subsidence rate. On average, the relative sea levels are rising along the west coast of Africa at a rate of less than +1 mm·year−1, with an overwhelming subsidence component, and negligible acceleration.

In arid regions, such as the Souf Valley in southeastern Algeria, agriculture is the main contributor to economic development. Groundwater irrigation is essential for agriculture, and if excessive or poorly planned, is a major cause of soil salinization. Despite the importance of this, soil salinization risk and groundwater quality here are little known. Therefore, in this study, we evaluated 41 wells in the Souf Valley region to investigate the quality and suitability of the groundwater for irrigation and associated soil salinization risks. Specifically, we performed water sample analysis across these wells, measuring the levels of physicochemical parameters (pH and electrical conductivity) and the concentrations of Ca2+, Mg2+, Na+, K+, SO42−, Cl−, HCO3−, and NO3−. In addition, geographic Information System (GIS) was used to assess and map both water quality and arable land loss due to salinization. The results of this study revealed the predominance of chloride, magnesium sulfate, and chloride-calcium facies. The groundwater nitrate concentrations reached 97.47 mg. L−1 and 92.5 mg. L−1 on the agricultural perimeters of Hassani Abdelkrim and Ourmes, respectively. This water is non-potable as it is too saline, making it unsuitable for irrigation purposes. Our study shows that groundwater pollution and soil salinization in the Souf Valley greatly threaten the future sustainability of agriculture here.

The traditionally used stabilizers like hydrated lime, Portland cement, and bitumen are becoming costly and can produce shrinkage and cracking in treated soil. An alternative, enzyme-based stabilizer can be used in clayey soil where shrinkage and cracking would be an issue. Enzyme-treated soil is more hydrophobic, resulting in the reduction of pore voids and increases in the amount of free water. The enzyme-treated soil is very much case sensitive and depends on types of clay minerals. In this research, a laboratory investigation and a numerical simulation are carried out on enzyme-treated fine-grained soil. The primary objective of this research is to study the effectiveness of an enzyme-treated soil as a compacted subgrade. Geotechnical properties of treated and untreated soil were determined at a curing period of 7 days, 28 days, and 60 days at varying enzyme dosages. The microstructure and elemental composition of soils and bio enzyme-treated soils were studied using energy dispersive X-ray spectroscopy (EDAX) and scanning electron microscopy (SEM). It is observed that the agglomeration and bonding between the particles in enzyme-treated soil are less effective at higher confining pressure. A mathematical expression has been proposed to predict the peak deviator stress of an enzyme-treated soil at various confining pressure. Numerical analysis was carried out using commercial software ANSYS. A five-layer pavement section was modeled as a 3D axisymmetric finite element section to determine the vertical permanent deformation and rebound (recoverable deformation) at different pavement layers under cyclic loading. Due to the enzyme treatment, the stabilized subgrade layer observed about a 33% reduction in permanent deformation.

To reconstruct the paleoclimate in North Africa during the Paleocene, the calcareous nannofossils were quantitatively analyzed at higher resolution from the stratigraphic succession of Gebel Nezzazat (west central Sinai, Egypt). The studied interval extends from NP4 to NP8. Zone NP4 can be subdivided into four subzones from base to top: NTp7B, NTp8A, NTp8B, and NTp8C. The base of the Selandian age is located at the base of NTp8B (Second Radiation of Fasciculithus). The Selandian/Thanetian boundary (S/T) is tentatively placed at the base of Zone NP7/8. The identified nannofossil zones were compared with that of the Tethyan region for the Danian/Selandian boundary. The calcareous nannofossil assemblages were used as indicators for medium-term climatic fluctuations. The pre-Danian (LDE) is dominated by the cool-water Zeugrhabdotus sigmoides and Neochiastozygus modestus, while the post-Danian interval is dominated by Coccolithus pelagicus and Ericsonia subpertusa. Before the onset of the Selandian-Thanetian boundary, a marked shift in the nannofossil species was observed, where Fasciculithus increased significantly, while marker Danian-Selandian genera (e.g., Lithoptychius Neochiastozygus, Chiasmolithus, and Cruciplacolithus) decreased dramatically. Non-Metric Multidimensional Scaling (nMDS) and permutational analysis of variance (PERMANOVA) in addition to the Temperature and Nutrient indices (TI and NI) indicated a marked difference between the warm eutrophic nannofossil assemblages at the Danian/Selandian (D/S) and the Selandian/Thanetian (S/T) transitions and the eutrophic cold-water assemblages during the background sedimentation. A sharp increase in sea surface temperature and decrease in nutrients was observed at D/S and represents the Latest Danian Event (LDE), while the second warming event was started prior to the Selandian and may represent the Early Late Paleocene Event “ELPE.” The sea-level lowstand may have limited water circulation, where surface water fertility decreased significantly. Consequently, nannofossil diversity decreased. The rapid recovery after the LDE was attributed to the radiation of warm-water taxa.

Rapid urbanization has led to the construction of important structures like bridges, flyovers and high rise buildings, mostly supported by pile foundations. In view of recent scarcity of land avoiding a particular construction site with poor soil deposit may not be a viable option. Hence, ground improvement has become an important remedial solution in the field of geotechnical engineering. Optimum depth of ground improvement required to achieve maximum lateral capacity of pile under seismic conditions is very much needed for practicing engineers. In the present study, Finite Element (FE) approach has been utilized to propose a simplified method to study the lateral response of pile under combined vertical and lateral load, installed in virgin as well as improved clayey deposit subjected to seismic motion. Nonlinear behavior of clay has been simulated using cyclic p-y curves. The number of equivalent uniform cycle for soil stiffness degradation has been considered based on earthquake magnitude. Stochastic simulation has been used to generate site specific earthquake accelerograms, considering different source to site distances. Comparison of pile behavior under different seismic motions of varying PBRA (Peak Bedrock Acceleration) have been done considering two different types of soil profile. The study reveals that with increased source to site distance, PBRA reduces whereas, PBRA increases with increased magnitude of earthquake. Maximum horizontal acceleration of soil (MHA) increases with increased earthquake magnitude and reduces with increased depth of ground treatment. Lateral pile head stiffness reduces with increased PBRA and increases with increased pile slenderness ratio up to L/D \(\le 20\), beyond which further increase of slenderness ratio reduces lateral pile capacity. Optimum depth of ground improvement for pile under seismic motion may be taken as about 6D to 8D for free head pile and 8D to 10D for fixed head pile.

This study was performed in major habitats of Gundelia tournefortii L. in the Central Zagros region, Iran, to pursue the two following objectives: (a) analyzing the percentage of canopy cover and density per unit area (m2) of the plant in controlling runoff and reducing the soil loss amount and (b) investigating some soil physicochemical properties and their impact on reducing the amount of runoff generation and sediment yield. The vegetation parameters of G. tournefortii L. were measured by completely randomized design using transect quadrat sampling method. It used a portable rainfall simulator apparatus. The highest amount of efficacy of the vegetation parameters of G. tournefortii L. in controlling runoff generation and sediment yield occurred during the first fifteen minutes of the rainfall continuity times in comparison to the second fifteen minutes of ones. As a result, in relation to runoff generation, the study sites No. 5 (1.73), No. 4 (1.85), No. 8 (1.90), and No. 1 (1.96) mm were allocated the largest contribution, respectively. Meanwhile, in relation to sediment yield, the following results were obtained. The study sites No. 5 (10.87), No. 4 (10.55), No. 8 (11.23), and No. 1 (11.35) g had the largest contribution, respectively. The findings showed that G. tournefortii L. has a prominent role in controlling runoff generation and sediment yield, and because of its high compatibility and deployment, it can be introduced as a suitable cover plant for soil conservation in natural fields.

Geothermal energy is one of the solutions for energy issues in sub-Saharan countries such as Cameroon, while addressing the environmental issues of the Paris Agreement. This study provides a new database on heat flow, radiogenic heat production, and geothermal gradient for the Adamawa region in Central Cameroon, which suffers from energy issues. This database serves as a framework for future research on geothermal energy for this region. Specifically, the study uses spectral analysis of Grid Earth Magnetic Anomaly (EMAG2) to present an overview of the thermal structure anomaly from surface events related to the volcanic activity of the Adamawa region. This spectral method has been applied to the magnetic data from the equator. The magnetic map was obtained from the correction of the reduction at the equator divided into 17 overlapping blocks of 100 × 100 km in order to estimate the Curie point depth (CPD), which allowed us to obtain the values for the heat flow, radiogenic estimate, and P-wave velocity (Vp). The depths vary from 16 and 41 km, while the heat flow varies from 91 to 98 mW m-2. The Adamawa region is characterized by low Curie point depth values due to the identified geothermal gradient regime that reveal the influence of near-surface mantle convection. In this region, the radiogenic heat production ranges from 0.024 to 0.303 μW m-3, with the low radiogenic heat values being related to heat flow. The seismo-tectonic activity in the region only involves high-intensity earthquakes produced along the Cameroon Volcanic Line as a subduction zone more precisely in the locality of Woulndé. The heat flow observed from the data may suggest the existence of an anomalous heat source in the crust due to radiogenic heat results.

Finite element analyses were conducted on two prominent cases of large-scale deep excavation in Central Jakarta, Indonesia. Large lateral wall deflections were observed during the final excavation stage, presumably due to clay’s time-dependent behaviour, for example, creep and consolidation (i.e., the excess pore water pressure being dissipated). Three-dimensional numerical analyses were executed using the soft-soil and soft-soil-creep models, which are advanced soil models, under the consideration of time-dependent effects. This study discovered that the time-dependent characteristics of clay in Central Jakarta contributed 23%–26% of the total wall deflection. Both soil creep and consolidation played a role in the major wall deformation in the final stage, and consolidation caused by the excavation had a stronger impact on wall deformation than did soil creep, with the impact being affected by the excavation area size, soft clay layer thickness, and presence of permeable materials (such as sand lenses).