Recent Alluvium Research Articles

Investigation of local soil properties of Erzurum province (Eastern Türkiye) by Horizontal/Vertical Spectral ratio method

Erzurum province is a basin developed under the effect of strike-slip faults in the Eastern Anatolia region. Erzurum province is generally influenced by the left strike-slip Erzurum Fault Zone, the left- strike-slip Aşkale fault, and the Başköy-Kandilli reverse fault. It is also located approximately 80 km from the Karlıova joint, which is the intersection of the North Anatolian and East Anatolian Faults. When the earthquakes of the instrumental and historical periods are analyzed, it is seen that many damaging earthquakes of medium to large magnitude have occurred in Erzurum province. Erzurum basin is generally covered with old alluvium at the edges of the plains, while the flat areas in the central parts are covered with new alluvium. Determination of local soil properties in regions with high earthquake hazard plays an important role in reducing earthquake risks. For this purpose, single station microtremor measurements were applied at 25 sites in Palandöken and Yakutiye districts of Erzurum province. The measurements were taken for at least 30 minutes and evaluated according to the Horizontal/Vertical Spectral Ratio method. As a result of the analysis, the dominant period, H/V ratio and vulnerability index (Kg) values of the measurement points were calculated. The period values obtained vary between 0.15 s and 3.7 s, while the H/V ratios vary between 2.2 and 8.5. The Kg value obtained using these parameters is defined as the vulnerability of the soil. It is concluded that high period, high H/V and high Kg values are obtained in areas with recent alluvium and multidisciplinary analyses should be performed in soil investigations in these regions.

Utilizing geophysical methods for assessing groundwater resources in the Dijil River Catchment, Northwestern Ethiopia

This study utilizes geophysical methods to assess groundwater resources in the Dijil River catchment near Debremarkos Town, Northwestern Ethiopia. Recent alluvial deposits and volcanic rocks of varying ages characterize the area. The aim is to map subsurface formations and evaluate groundwater potential. Two hundred twenty-eight magnetic data were collected, mainly oriented in NE-SW, NW-SE, E-W, and N-S directions, and twenty-four Vertical Electrical Sounding data utilizing the Schlumberger configuration. The results of the magnetic data reveal lineaments in different directions in the study area. Most of the Geoelectric sections show three layers, of which the second or the third layers are aquifers having minimum and maximum resistivity of 6 and 155 Ohm.m, respectively, and average resistivity range of 13–50 Ohm.m with a thickness ranging 24–200m. The layers represent alluvial deposits, highly weathered and fractured basalt (major aquifer zone), and moderately to slightly weathered and fractured basalt. Shallow and deeper low resistivity horizons, indicating groundwater saturation zones, are visible. The integrated geophysical survey aligns well with available borehole data.

Late Pleistocene to Holocene alluvial deposits of the Inaouène Valley and their paleoenvironmental significance (north Morocco)

This study investigates the paleoenvironmental changes and fluvial dynamics in the Inaouène River Valley of central northern Morocco over the last 22,000 years. Through comprehensive field study and radiocarbon dating of Upper Pleistocene and Holocene alluvial deposits, the research identifies six main alluvial units reflecting distinct phases of fluvial activity and environmental conditions. These phases include coarse gravel aggradation between ∼22 and 15 cal kaBP, indicating a braided channel system, followed by multiple fine-dominated alluviation phases occurring at ∼13, ∼10, ∼6–5, ∼3, ∼0.7–0.3, and ∼0.1-0 cal kaBP. The trunk channel evolved from a low-sinuosity wandering style in the Early-Middle Holocene to a high-sinuosity pattern in the Late Holocene. Periods of landscape stability, evidenced by soil formation, were dated around 0.3 and 0.8 cal kaBP, with additional episodes estimated just after ∼12 cal kaBP and around 3.8 cal kaBP. Notably, the study also uncovered evidence of significant human intervention during the Middle Holocene.A comparison with other archives enabled us to reconstruct late Pleistocene and Holocene palaeoenvironmental conditions on both regional and supraregional scales, linking specific stages of floodplain development to prevalent influencing factors. Emphasizing the fluvial system response, we present a cause-effect model that focuses on long-lasting climatic phases (e.g., Last Glacial Maximum, MIS2-MIS1 transition, African Humid Period) as well as sub-millennial to centennial Rapid Climate Changes, North Atlantic cooling events, and solar activity minima. Human intervention played a key role in the Inaouène's evolution during the Middle Holocene, as evidenced by clear anthropogenic markers found in the associated deposits. These findings not only contribute to our understanding of the area's geomorphological history but also highlight its significant archaeological potential, opening new avenues for interdisciplinary research in this understudied region.The study offers new insights into central northern Morocco's late Quaternary alluvial geochronology and paleoenvironmental evolution, aligning with regional findings and contributing to a broader understanding of climate-driven landscape changes and human-environment interactions across North Africa and the Mediterranean.

Geochemical distribution of major and trace elements in hydromorphic soil profiles developed on recent alluvium

Geochemical composition and distribution of major elements study is vital in terms of investigating the major soil forming compounds and to know the fate of trace elements in soils. Particle size distribution (PSD), pH, organic carbon (OC), and major and trace elements of hydromorphic soils formed on recent alluvium in Obafemi-Owode Local Government Area of Ogun state, Nigeria were analysed using standard procedures. Three profiles pits were dug based on the mapping units identified, and samples were collected for laboratory analysis. Data were subjected descriptive statistics and Pearson’ correlation coefficients using IBM SPSS version 27. The PSD was dominated by sand content, followed by clay and silt, and soil pH in KCl was strongly acid (3.17–4.30) and pH in H2O was moderately acid (4.74–5.80), while OC contents were low to moderate (1.22–6.69 g/kg). The major elemental results showed higher concentration of SiO2 (>50 %) connotes presence quartz, feldspar, and clay minerals. Manganese, Cu, Ba, Zr, and Zn have higher concentrations among the trace elements. Major elements ratios (SiO2/Al2O3, K2O/Al2O3) showed moderate weathering stage, while trace elements ratios (Ni/Co and Cu/Zn) revealed deposition under humid conditions and anoxic environment. The statistical analysis revealed that most elements have skewness closed to zero except MgO and K2O. Correlation coefficients between the elements are positive and significant (p < 0.05 and p < 0.01) indicating that their presence can be accounted for by similar lithology, though some have negative relationship which could be as a result of anthropogenic activities. The study found that elements were potential tracers for the presence of human activities and environmental changes.

GEOLOGY AND THE STUDY OF HEAVY METAL IMPACTS ON ENVIRONMENTAL QUALITY ASSESSMENT USING ARCGIS FOR INTERPRETATION DISTRIBUTION

The Boto area, Jatiroto District, Wonogiri Regency, Central Java, Indonesia, is a traditional gold mining site with inadequate waste management practices, particularly mercury usage. This study aims to assess mercury contamination and evaluate phytoremediation potential in the area. Geological mapping, petrographic analysis, fossil analysis, stereographic analysis, soil Hg measurement, soil and water chemistry analysis, and XRF analysis were conducted to characterize the geology, geomorphology, and heavy metal distribution. The study area is divided into four geomorphological units: Intrusive Hill Unit (V1), Homoklin Hill Unit (S1), Karst Hill Unit (K1), and Alluvial Plain Unit (F1). Stratigraphically, the area consists of the Nglanggeran Breccia Unit interbedded with early Miocene lava, the early Miocene andesite Intrusion Unit with a terrestrial depositional environment, the Wonosari Limestone Unit of Middle-Late Miocene age, and the Holocene Alluvial Deposit Unit. Geological structures include left-lateral normal faults trending relatively north-south (Sesar Boto), left-lateral normal faults trending southeast-northwest (Sesar Brenggolo), and right-lateral downthrown faults trending southeast-northwest (Sesar Mesu). Fractures and veins are also present. Mercury (Hg), manganese (Mn), arsenic (As), and lead (Pb) distribution mapping was conducted. The contaminated zone falls into TCLP-A, and waste management falls into category 1, located in Boto Village, which is a gold mining and processing area. Phytoremediation is proposed as a remediation strategy. Keywords: gold mining, heavy metals, XRF, phytoremediation, distribution

Geoarchaeology of open-air sites of the Foz do Chapecó area in the upper Uruguay river, southern Brazil

This paper presents the results of the investigations that defined the formation of the sedimentary deposits and the chronological sequence of the Foz do Chapecó archaeological area in the Volta Grande of the Upper Uruguay River, Southern Brazil. This research was undertaken to contribute to the definition of the diachronic, sedimentary and stratigraphic context of the archaeological occupations. To achieve these goals a geoarchaeological prospection by land and water was conducted, focusing on the valley bottoms, in the whole Volta Grande area. It comprehended the characterization of surface sedimentary deposits, the exposure and analysis of stratigraphic profiles, and sedimentological analysis. Four superficially exposed deposits were identified: i.e., fluvial conglomerates, fine sediments with sandy texture, clay colluviums and current and recent alluvial deposits. Six interesting points for the opening of stratigraphic profiles were identified, and subsequently resulted in the identification of sedimentary facies associated with river-bed, colluvial and colluvial-alluvial deposits. Three of these points presented a clear sequence of archaeological levels in the stratigraphic context. The results indicated that the local sediments are predominantly composed of a variable mixture of silt and clay, with sands occurring predominantly in an interdigitated form. The stratigraphic structure of the identified layers led to the establishment of 7 sedimentary facies, associated with colluvium (Cm), colluvium-alluvium (Sm) and alluvium and fluvial channels (Sm, Fl, Gms, Gt, Gp, Gh). The radiocarbon dating gives an age between 12.0 and 0.3 cal kBP, indicating that the filling of the local valley occurred during the end of the Pleistocene and throughout the Holocene by means of both fluvial and colluvial systems. Nine distinct archaeological levels, with a clear stratigraphic, chronological, and technological characterization were identified. The pre-ceramic archaeological sequence shows the following chronology: the oldest occupation occurred between 12.0 and 11.0 cal kBP (Cm facies); this was followed by an occupation between 10.5 and 9.5 cal kBP (Cm, Gt, Gp and Gh facies in three archaeological sites with eleven 14C data), then an occupation between 8.7 and 8.5 cal kBP (Cm facies), another between 5.7 and 5.5 cal kBP, one more between 4.8 and 4.6 cal kBP (Cm facies), and the last between 3.4 and 3.3 cal kBP (Cm and Sm facies). The ceramic phase seems to form a single dense component with the anthropogenic soil formation, and was dated between 0.5 and 0.3 cal kBP (Sm facies). These data present a previously unpublished chronostratigraphic sequence that is unique for the context of open-air sites in inner southern Brazil.

Electrical Resistivity - Tomography Studies In Determining Shallow Aquifer Potential Zones a Case Study in Different Terrains

The study documents the effectiveness of 2 D (Two Dimensional Electrical Resistivity Survey (Tomography) to map shallow subsurface geological formations namely recent Alluvium, Gondwana deposits and hard rock deposits. 2 dimensional Electrical Resistivity Survey (or tomography) was conducted at 2 locations at Valarpuram and one location Madurantakam areas. Gondwana deposits mask Valarpuram Thandalam, villages (at Kancheepuram District, Tamilnadu). To the east of Valarpuram alluvium thickness increases at shallow depths. Weathered and hard granitic gneiss and hard charnockite rocks overlie topsoil in Madurantakam areas (Chengalpettu District, Tamilandu). The survey was conducted to 12 m depth to decipher shallow permeable zones. Gondwana formations consisting of clays, siltstones are predominant in Valarpuram Thandalam and surrounding areas. Hard rock formations are found in Madurantakam areas. 2 Dimensional Resistivity Survey results indicate 2-D sections with very low resistivity values in the range of 2 to 4 ohm-m in Valarpuram Thandalam areas indicating predominant clay deposits with poor ground water potential. To the east of Valarpuram Thandalam resistivity data is of moderately higher value indicating sand deposits at shallow depths. These are ideal locations for dug wells. Low to moderate values at shallow depths indicating weathered thickness up to 12 m are observed at Madurantakam location. From 12m depth steep rise in resistivity values are observed in hard indicating presence of massive rock from 12m depth and below areas. Thus, 2 D Resistivity Imaging Technique are helpful in delineating shallow aquifer potential and this in turn helps in deciding the depth of open wells with high precision.

Influence of the 2020 Seismic Hazard Update on Residential Losses in Greater Montreal, Canada

Greater Montreal is situated in a region with moderate seismic activity and rests on soft ground deposits from the ancient Champlain Sea, as well as more recent alluvial deposits from the Saint Lawrence River. These deposits have the potential to amplify seismic waves, as demonstrated by past strong, and recent weak, earthquakes. Studies based on the 2015 National Seismic Hazard Model (SHM5) had estimated losses to residential buildings at 2% of their value for an event with a return period of 2475 years. In 2020, the seismic hazard model was updated (SHM6), resulting in more severe hazards for eastern Canada. This paper aims to quantify the impact of these changes on losses to residential buildings in Greater Montreal. Our exposure database includes population and buildings at the scale of dissemination areas (500–1000 inhabitants). Buildings are classified by occupancy and construction type and grouped into three building code levels based on year of construction. The value of buildings is obtained from property-valuation rolls and the content value is derived from insurance data. Damage and losses are calculated using Hazus software developed for FEMA. Losses are shown to be 53% higher than the SHM5 estimates.

Factors controlling groundwater Arsenic concentration in the Red River Delta, Vietnam

The Red River Delta (RRD) has a high population density with about 19 million inhabitants. Water supply is from surface water and groundwater resources, in which surface water is from rivers and groundwater is mainly taken from aquifers in Quaternary sediments. Last two-decade research’s results show that groundwater in some areas in the RRD are contaminated with high elevated levels of Arsenic. Many research studies investigating Arsenic pollution have found that concentrations in water samples surveyed in Hung Yen, Hanoi, Ha Nam etc exceed the permissible value for domestic use as WHO guideline and Vietnam standard as well. The key factors controlling the distribution of Arsenic in the groundwater from previous studies are formation environment, sedimentary facies, sedimentary age, salinity of pore water and even neo-tectonic activity. However, which factor is more important for controlling groundwater arsenic distribution in the RRD need to be clarified. Therefore, the objective of this study is to determine the degree of controlling factors on the distribution of Arsenic in groundwater in the RRD. An overview of previous studies on the origin of Arsenic in groundwater is the first step to analyse the factors affecting the distribution of Arsenic in groundwater. A method of superposition of the controlling factors on the basis of ArcGIS was applied. Each controlling factor was classified and assigned a certain value. The weights of the factors were determined based on expert opinions and analytical hierarchical process (AHP) method. The results of model calibration based on the current distribution of Arsenic concentration map of the Holocene and Pleistocene aquifers allow confirming the reliability of the weights of controlling factors. Research results show that the groundwater Arsenic concentration in the RRD depends mainly on the distribution of Holocene alluvium and its age. The remaining factors are very insignificant in this case.

Accumulation Pattern and Risk Assessment of Potentially Toxic Elements in Permafrost-Affected Agricultural Soils in Northeast China.

The accumulation of potentially toxic elements (PTEs) in agricultural soils is of particular concern in China, while its status, ecological risks, and human health hazards have been little studied in the permafrost areas of Northeast China. In this study, 75 agricultural soil samples (0-20 cm) were collected from the Arctic Village, Mo'he City, in the northernmost part of China. The average concentration (mean ± standard deviation) of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were 12.11 ± 3.66 mg/kg, 0.11 ± 0.08 mg/kg, 52.50 ± 8.83 mg/kg, 12.08 ± 5.12 mg/kg, 0.05 ± 0.02 mg/kg, 14.90 ± 5.35 mg/kg, 22.38 ± 3.04 mg/kg, and 68.07 ± 22.71 mg/kg, respectively. Correlation analysis, cluster analysis, and principal component analysis indicated that As, Cu, Ni, and Zn likely originated from geogenic processes, Hg and Pb from long-range atmospheric transport, Cd from planting activities, and Cr from Holocene alluvium. The geo-accumulation index and enrichment factor showed that As, Cd, Hg, and Zn are enriched in soils. The Nemerow pollution index showed that 66.67%, 24%, and 1.33% of soil samples were in slight, moderate, and heavy pollution levels, respectively, with Hg being the most important element affecting the comprehensive pollution index. The potential ecological risk index showed that 48.00% and 1.33% of soil samples were in the moderate ecological risk and high potential ecological risk levels, respectively. The non-carcinogenic and carcinogenic human health risk index for adults and children were both less than 1, which was within the acceptable range. This study revealed the accumulation pattern of PTEs in agricultural soils of permafrost regions and provided a scientific basis for research on ecological security and human health.

Surface rupture and landscape response in the middle of the great Mw 8.3 1934 earthquake mesoseismal area: Khutti Khola site

Large earthquakes breaking the frontal faults of the Himalayan thrust system produce surface ruptures, quickly altered due to the monsoon conditions. Therefore, the location and existence of the Mw8.3 1934 Bihar–Nepal surface ruptures remain vividly disputed. Even though, previous studies revealed remnants of this surface rupture at the western end of the devastated zone, ruptures extent remains undocumented in its central part. Evidence for recent earthquakes is revealed along the frontal thrust in this region. The Khutti Khola river cuts an 8 m-high fault scarp exposing Siwalik siltstone thrusted over recent alluvial deposits, with faults sealed by a colluvial wedge and undeformed alluvial sediments. Detrital charcoals radiocarbon dating reveals that the last event occurred between the seventeenth century and the post-bomb era, advocating for the 1934 earthquake as the most recent event. In the hanging wall, fluvial terraces associated with fault scarps were abandoned after a penultimate event that happened after the tenth century, a rupture we associate with the historic earthquake of 1255CE. Slips of 11–17 m and 14–22 m for the 1934 and 1255 earthquakes, respectively, compare well with the ~ 10–15 m slip deficit accumulated between the two earthquakes, suggesting that most of the deformation along the front is accommodated by surface-rupturing earthquakes.

Basement structure of the Northern Foothills Fold and Thrust Belt and southern Fairbanks and Salcha, Alaska Seismic zones and their relation to large (M ≥ 6) earthquakes

We used seismic, gravity and aeromagnetic information to better define the basement structure of the southern Fairbanks and Salcha seismic zones and the Northern Foothills Fold and Thrust Belt (NFFTB), regions that accommodate deformation in interior Alaska north of the Denali fault. At least five earthquakes of M ≥ 6 occurred within this region between 1929 and 1947. Relocated epicenters of two foreshocks and the October 16, 1947 (Mw 7.2) mainshock suggest they occurred in a topographically low area covered with recent alluvial deposits located ∼20 km north of the northernmost mapped thrusts of the NFFTB, although the largest aftershock of the sequence occurred within the exposed NFFTB. The three largest events of the 1947 sequence had similar waveforms, indicating similar mechanisms. Relocations of the 1929 events, also with waveforms similar to the 1947 sequence, indicate they likely occurred along thrust faults associated with the exposed NFFTB. In contrast, the 1937 sequence (mainshock of Mw 7.3) involved strike-slip rupture along the Salcha seismic zone. We constructed and modeled three gravity/aeromagnetic profiles extending across the NFFTB to the northwestern edge of the Tanana Basin that support the presence of subsurface thrusting north to 64.4°N, coincident with the absence of the Totatlanika schist at this latitude. A third profile extending across the Salcha seismic zone suggests reactivation of high angle faults within the Yukon-Tanana crystalline complex. The extension of thrust faulting ∼20–30 km north of the exposed NFFTB has important implications for the seismic hazards of the Fairbanks region.

Application of Probabilistic Seismic Hazard Assessment to Understand the Earthquake Hazard in Attock City, Pakistan: A Step towards Linking Hazards and Sustainability

Within the last three decades, twelve major earthquakes (Mw &gt; 6.0) have jolted Pakistan and contributed to a heavy death toll and an economic loss of billions of dollars, which is immense for any underdeveloped country. Despite the generalized description of seismic hazards in various regions of Pakistan, densely populated cities still require a detailed and integrated vulnerability analysis to overcome the impact of a significant earthquake. This study aims to integrate seismic hazard assessment schemes to understand the vulnerability of Attock city against an earthquake. It initially evaluates the threat from an earthquake due to tectonic activity in the region, splits the region (about 200 km radius) into six seismic zones and uses area source parameters. The ground motion prediction equations compatible with the study area’s seismotectonic environment are also used in this study. Peak horizontal ground acceleration (PGA) and 5% damped spectral acceleration are critical features of ground motions. The site classification is carried within Attock city, indicating the presence of SB (foundation condition with Vs30 = 760 m/s), SC (foundation condition with Vs30 = 400 m/s) and SD (foundation condition with Vs30 = 300 m/s). The peak ground accelerations for a return period of 475 years at the SB, SC and SD sites are estimated as 0.23 g, 0.28 g and 0.30 g, respectively. Uniform hazard spectra are obtained for each site classification at three return periods (475, 975 and 2475 years). Another possible threat can be the local site conditions of the study area, as Attock city exists on the unlithified sediments of upper Pleistocene to Recent alluvial deposits. That is why microtremor recordings are conducted at 20 sites within Attock city to understand the fundamental frequency (f0), horizontal to vertical spectral amplitude (A0) and Kg parameter, a seismic vulnerability index. The values of f0 are found between 0.6 and 9 Hz and A0 is observed between 2.1 and 5 Hz, whereas the Kg is estimated between 0.24 and 20 Hz. Despite evidence of the seismic vulnerability of Attock city, the current building designs and infrastructure development are not synchronized with the uniform hazard response spectra and the soil amplification, thus enhancing the exposure of the study area to disaster during a major earthquake. This study will be instrumental in pre-disaster mitigation strategies for urban planners and policymakers.

Characterisation Of Complex Ground Conditions For The Rozelle Interchange Project

The Rozelle Interchange Project (RIC) in Sydney is an underground motorway interchange connecting multiple underground and surface arterial roads as well as the future Western Harbour Tunnel and Beaches Link. RIC completes the WestConnex program of works and is a complex array of approximately 22 km of multiple level tunnels, all constructed in an area 2.5 km long and 1.5 km wide. RIC is located within complex ground conditions that include deep soils, regional faults, structural zones and igneous intrusions. Deep natural soils infilling a valley near Rozelle Bay are mostly recent Holocene alluvial, marginal marine and marine deposits. These soils are interlayered, discontinuous, normally to slightly over consolidated and capped by sand and coarse rockfill from 19th century reclamation. There is a strong contrast in the level of detail between borehole and CPT data. Distilling this to provide a geological and geotechnical model for a project wide interpretive report for designers of multiple structures required a hybrid approach to model presentation. This included providing a simplified graphical model and including details from specific investigations and laboratory testing allowing designers flexibility to adopt appropriate parameters for their specific application. Similarly, the rock structural model evolved from development of structural domains to identification and inclusion of regional geological structures overprinting the structural model. Regional scale thrust faults, corridors of structural complexity and igneous intrusions were identified and refined prior to and throughout the design process. These were considered in the design by modification of excavation sequencing and changes to tunnel support. Tunnel excavations encountered these regional features at the locations predicted and with similar character as those described in the model allowing the safe construction of the tunnels.

Geochemical and mineralogical characterization of Ria de Aveiro (Portugal) saltpan sediments for pelotherapy application.

The present study aims to characterize sediments textural, geochemical and mineralogical composition used in a SPA for pelotherapy applications. Six samples were collected in two areas of an open-air saline SPA, a former saltpan in Ria de Aveiro (Portugal). Sampling areas are predominantly composed by recent alluvium that had been affected by chemical industrial effluents for over 50years. Samples < 2000, 63, and 2µm fractions were analyzed by X-ray Diffraction (XRD) and X-ray Fluorescence (XRF), for identification of mineral phases and chemical composition. SEM analysis was used for individual particles morphological characterization and chemical semi-quantification. Texture, mineral phases and chemical composition showed the influence of SPA pond beneficiation works. The two SPA areas revealed distinct mineral phases, one with higher quartz content, and the other with higher halite content, consistent with their environmental conditions. Illite constituted the most abundant mineral phase of the clay fraction. Preliminary results suggested concentrations of potential toxic elements (e.g., As, Cd) above reference values, representing a risk to the ecosystem and humans.

The influence of alluvial stratigraphic architecture on liquefaction phenomena: A case study from the Terre del Reno subsoil (southern Po plain, Italy)

Earthquake-induced liquefaction phenomena are commonly observed at shallow depths or at the ground surface above Holocene alluvial deposits. Nonetheless, a high-resolution examination of the relationship between surface manifestations and alluvial stratigraphy has been rarely attempted. In this study, we provide a detailed subsurface model from a selected sector of the southern Po Plain affected by widespread liquefaction processes triggered by the 2012 Emilia-Romagna seismic crisis. We report a comprehensive sedimentological and CPT-based characterization of the Terre del Reno subsoil and investigate how the stratigraphy controls earthquake-induced liquefaction phenomena. The main facies associations making up the alluvial subsoil constitute the basic elements of the liquefaction system, herein named host, source and sedimentary cap. Their subsurface distribution documents the presence of fluvial bodies prone to liquefaction beneath the earthen levees and across an area dominated by flat muddy floodplain deposits with no physical evidence of paleochannels at the surface. In addition, our observations suggest that vertical and lateral changes in stratigraphy control the mode and location of liquefaction evidence at the surface in both settings. In particular, the relative thickness of fluvial channel bodies vs. channel levee deposits (source–seal couplet) appears to control the severity of sand ejection at the surface. Our findings also suggest that vertical and lateral discontinuities within source layers prevent the occurrence of widespread liquefaction features. Conversely, lateral spreading effects and differential underground hydrostatic pressure at the interface between saturated and less permeable units are accountable for repeated sand ejection along surface fractures. This case study constitutes a unique natural laboratory thanks to the quality and density of available data. However, we emphasize that a similar approach can be useful to promote source-layer identification in areas characterized by poor or sparse data and to mitigate liquefaction hazards in urban areas built on alluvial plains.

Textural and geochemical characteristics of the Yikpata river channel sands, Nigeria

The Yikpata river is one of the major rivers that empty into the River Niger, Nigeria. River Niger cuts across the Bida Basin thereby contributing to the alluvium deposits found within the Bida Basin. The properties and compositions Yikpata river channel sediments input in the River Niger where alluvium deposits are found is yet to be documented. Furthermore, the geology of where the studied river is located is sparse. Therefore, the textural, petrological, and geochemical analyses were used to examine the Yikpata river channel sediments for their compositions and characteristics in other to infer their provenance, tectonic settings and chemical weathering intensity as well as give information about sediments that are been transported as recent alluvium along River Niger in the Bida Basin. This study likewise lays some foundations for the comprehensive assessment of watershed environmental quality. This study revealed that the Yikpata river channel sediments are moderately well to poorly sorted sediments and were classified as sub-arkose based on log Na2O/K2O vs SiO2/Al2O3. Low CIA, PIA, ICV, Rb/Sr values, and ternary plot of A-CN-K demonstrate that the river sands were derived from low to moderately weathered source rocks and the major-element-based discrimination diagrams revealed that sediments were from a rift tectonic setting (passive margin). Additionally, the river sediments are derived from weathered sedimentary rocks that are of the felsic source, based on the major element discriminates functions, TiO2 vs Zr, Al2O3/TiO2, La/Sc, La/Co, Th/Sc, Cr/Th and LREE/HREE. The pollution status of the river from the sediments revealed that the river is currently not polluted and the sediment is not toxic.

Application of Seismic Reflection Survey for Aquifer Layers Characterization at the Felda Lepar Utara Area, Pahang, Malaysia

Precise determination of subsurface structure is crucial in hydrogeological studies to correctly determine the potential of groundwater resources, and the sustainability of those resources. This study used the seismic reflection method to characterize the aquifer layer in Ladang Lepar Utara 8 (Line 1) and Ladang Sungai Rengai (Line 2) in the Felda Lepar Utara area, Pahang, Malaysia, due to its high accuracy, high-resolution and deeper penetration. The field data acquisition survey involved roll-along techniques with shot spacing of 5m along the line using 24-channels ABEM terraloc Mark-6 and CMP (common mid-point) profiling techniques. Seismic interpretation of reflection data and tubewell information from nearby borehole data indicates that the area consists of a single type of rock known as phyllitic meta-sedimentary rocks of the Sri Jaya beds that have been deformed by intense faulting and fracturing (from about 30 to 750 m depth in Line 1 and about 75 m to 500m depth in Line 2). This formation is overlain by recent alluvium that ranges in thickness from 30 to 75 m and is underlain by Lepar Granodiorite. The alluvium is a shallow aquifer system that can be classified as an unconfined aquifer, whereas the phyllitic meta-sedimentary rock of the Srijaya Beds is a deep aquifer system that can be classified as a confined aquifer with an alluvium layer (up to 75 m thick) on top as a confining bed. The occurrence of intense faulting and fracturing increases the porosity and permeability of the rock formation and hence increases its potential as a groundwater prospective/promising zone.

Application of Chemostratigraphic Methods to Floodplain Alluvial Deposits within the Big Harris Creek Basin, North Carolina

Big Harris Creek, North Carolina, possesses a geomorphic history and alluvial stratigraphic record similar to many drainages in southern Appalachian Piedmont. An approximately 1 km reach of Upper Stick Elliott Creek, a tributary to Big Harris Creek, was used herein to (1) explore the use of chemostratigraphic methods to define and correlate late Holocene alluvial deposits along this relatively uncontaminated rural stream containing legacy sediments (historic, anthropogenically derived deposits), and (2) interpret depositional floodplain processes within small (&lt;10 km2), headwater drainages. The lithofacies within four floodplain sections were described in channel banks and sampled at about 5 cm intervals. The 128 collected samples were then analyzed for grain size and the concentration of 22 elements using X-ray fluorescence. Well-defined chemostratigraphic units (facies) were defined on the basis of a multi-elemental fingerprint using a principal component analysis (PCA) and verified using discriminant analysis (DA). Chemostratigraphic units did not reflect grain size at a site (by design) but marginally correlated to lithofacies defined by field descriptions. Of significant importance, chemostratigraphic units could be quantitatively correlated between the four stratigraphic sections at a much higher spatial resolution (~5 cm) than could be performed using other sedimentologic parameters alone. In combination, the lithostratigraphic and chemostratigraphic architecture of the floodplain is consistent with a previously proposed sequence of deposition for the legacy deposits in which extensive land-use change associated with the onset of cotton farming in the 1860s led to upstream incision and gully formation and downstream deposition on the floodplain surface. Deposition appears to have progressed downvalley as incision deepened, probably in the form of crevasse splay deposits or proximal sandsheets that were occasionally interbedded with vertically accreted sediments. The results indicate that chemostratigraphy represents a highly useful approach to the assessment of floodplain depositional processes over (at least) relatively small temporal and spatial scales, even in areas with minimal sediment contamination.

Hydrogeochemical variability and appraisal of water quality of groundwater in Mahoba district, Uttar Pradesh, India

Mahoba district comes under the state of Uttar Pradesh (U.P.), India which is a part of mighty Bundelkhand Granitic Terrain known for its water debt condition. The region is hard rock terrain having recent alluvium cover of variable thickness relating to slope and level of erosion. Secondary porosity i.e. in the fractures and cracks present hosts the groundwater in the study area. The high-water scarcity and poor drinking quality led us to carry out our research work in the study area. The water facies analysed shows Ca–Mg–HCO3 and Na–HCO3 water types which indicated their compositional source from rock and anthropogenic inputs. Majority of the samples showed the dominance of alkaline earths over alkalies and weak acids over stronger counterparts. The correlation coefficients calculated between hydrochemical parameters projects a strong positive correlation of EC and TDS with most of the major ions, including SO42−, NO3−. The hierarchical cluster analysis of all samples was classified into five clusters (C1A, C1B, C2A, C2B1 and C2B2). The sites of cluster C1 water samples were found located closer to drainage streams than C2 cluster water samples. The excessive fertilizers, unplanned municipal wastes and agricultural wastes resulted in high SO42− and NO3−. High F− showed concentration in various samples may have geogenic sources due to flour-apatite in granitic terrain and Fe found in excess gives an unpleasant taste on drinking. The analysed irrigation parameters (%Na, MR, TDS, RSC, SAR, TH, and KI) revealed perfect under permissible quality. Various negative human health issues like indigestion, bone problems, alimentary canal problems have been seen due to excess of SO42−, NO3− and F−). The study reflects the need for immediate preventive measures to improve drinking quality from health alarming ion concentrations and also would help for further management programs.