Groundwater Flow Patterns Research Articles

Assessment of hydraulic connectivity among shallow and deep aquifers and surface water of Central Gujarat: An isotopic approach

The primary objective of this study is to identify the surface water - groundwater interaction and interaction among groundwater at different depths using stable isotopes (δ18O and δ2H). The Fence diagram of the study area describes the subsurface geology where the main aquifer system includes both confined and unconfined in the VRB area and is complex multi-layered with different sources of recharge. The flow pattern of groundwater is generally from the highland of north-east to low-lying south-west of VRB and is indicated by the piezometric surface map of pre-monsoon, and post monsoon, 2016. The δ2H (‰ VSMOW) and δ18O (‰ VSMOW) values do not show any symmetric distribution among them. The values for shallow groundwater ranges between −23.0‰ and 1.9‰, and −3.2‰–2.3‰, respectively with a mean value for δ18O and δ2H are −1.26‰ and −11.194‰ respectively. The depth wise interpretation revealed that the locations Virpur and Nana Pura show connectivity. Therefore, deep and shallow aquifers are contaminated due to this connectivity. The plots of d-excess vs. electrical conductivity, d-excess vs δ18O and electrical conductivity vs. δ18O indicate that most of the groundwaters are primarily influenced by evaporation process, high mineral dissolution and enrichment of δ18O. The plot of δ18O vs. nitrate indicate the anthropogenic influences like agricultural activities in this region. The SI values of calcite and dolomite indicates oversaturated condition along with dissolution of these minerals in the aquifer matrix.

Hydrologic windows into the crystalline basement and their controls on groundwater flow patterns across the Paradox Basin, western USA

Conceptual models of sedimentary basin groundwater flow systems typically assume that the crystalline basement acts as an impermeable boundary and can be neglected. In this study, we use hydrologic models constrained by isotopic and geochemical datasets to argue that the La Sal Mountains, Utah, USA, act as a hydrologic window into the Paradox Basin’s lower aquifer system and underlying crystalline basement. We conducted a sensitivity study in which we varied crystalline basement/laccolith permeability as well as fault zone connectivity along a cross-sectional transect from the La Sal Mountains to Lisbon Valley. When the crystalline basement/laccolith units are set at relatively permeable levels (10−14 m2), simulated tracers that include total dissolved solids, oxygen isotopic composition of pore fluids (δ18O), and groundwater residence times are in closest agreement with field measurements. Model results indicate that pore fluids in the basal aquifer system underlying the Paradox Formation confining unit are a mixture of relatively young meteoric fluids and older Paradox Formation brines. The presence of faults did not significantly modify fluid exchange between the upper and lower aquifer systems. This was due, in part, to underpressuring within the Paradox Formation. Our study concludes that the Paradox Basin represents a regional recharge area for the Colorado Plateau, with groundwater discharge occurring along the Colorado River within the Grand Canyon some 375 km away to the southwest. This is only possible with a permeable crystalline basement. Our findings help explain the genesis of Mississippi Valley-type ore deposits of the US Midcontinent, where the presence of a permeable basement may be useful in addressing issues related to solute mass and energy balance.

Groundwater level response to precipitation at the hydrological observatory of Pinios (central Greece)

To study groundwater dynamics and their response to precipitation in the Pinios river basin (central Greece), the variation trends and seasonal patterns of fourteen monitored groundwater and two precipitation time series were examined using time series decomposition, autocorrelation, and wavelet analysis. The objective is to perform indirect methodologies based on groundwater level and precipitation data to attain a detailed understanding of the hydrogeological mechanisms of the aquifer system and develop an approach that can be easily employed worldwide. The three approaches confirm local groundwater circulation understanding by dividing the aquifer system into three parts characterised by varying transmissivity and storativity properties. The extended memory effect, ranging between 70 and 230 days suggests great inertia and storage capacity of the examined groundwater system. The wavelet analysis proves that the system acts as a filter which absorbs the precipitation frequencies converting them into GWL signals, as demonstrated by the 256 days periodicity shared by groundwater level and precipitation time series. Generally, GWLs present a hysteresis to precipitation due to the geological setup and local flow conditions and are particularly affected by a seasonal component, as also highlighted by time series decomposition. An evident annual periodicity is also observed in hydrological and hydrogeological time series. Results suggest the effectiveness of the proposed combination of methods in developing hydrological understanding and their general applicability to other regions where at least groundwater level and precipitation time series are available. By utilising such data-driven approaches, hydrogeologists and water resource managers can gain valuable insights into the behavior of aquifers, groundwater flow patterns, and the impact of human activities on groundwater quality and quantity.

Hydrogeological and hydrochemical condition in planned tunnel B route of the Yogyakarta-Bawen toll road

The Yogyakarta-Bawen toll road tunnel, located in Magelang Regency, Central Java Province, is a national strategic project that connects Central Java and the Special Region of Yogyakarta. It has geology resulting from volcanic processes, resulting in rocks with moderate aquifer properties and low to moderate permeability. The study covers 24 observation points, with 11 locations sampling groundwater for chemical analysis. The analysis results of hydrochemical facies are Na-K-HCO3. Water table depth varies from 623 m to 704 m above sea level, with the water table along the tunnel route at depths of 13-40 m above mean sea level, generally above the tunnel’s elevation. The groundwater flow pattern tends to move from southeast to northwest, perpendicular to the tunnel’s direction. Groundwater quality testing indicates that water in the research area falls under the category of fresh groundwater, based on electrical conductivity and total dissolved solids values. The overall acidity level is generally acidic, except at specific points. In general, the interaction of groundwater with concrete results in weak erosion. It can be concluded that the groundwater at the research location is shallow, situated above the planned tunnel elevation, exhibits hydrochemical facies variations, and has the potential to weakly erode concrete.

Combining geomechanical and hydrogeological modeling for drainage analysis in Block Caving mine development

Underground caving operations are naturally affected by mud and water inflows. These inflows occur mainly because caving operations are connected to a surface or a previous mining area through a broken subsidence zone where there is potential to accumulate water. Additionally, the surface/groundwater can mix with fine fragments within the broken column, which can generate a sudden mud rush through the drawpoints. A key mitigation measure for this hazard is drainage of the surrounding rock mass. However, an effective mine drainage system can be designed only if the physical behavior of groundwater flow is known. This work proposes a methodology that couples a geomechanical model designed in FLAC3D© with a hydrogeological model developed in FEFLOW©. The geomechanical model determines the spatial and temporal distribution of the stress field and induced strain due to caving. The spatial and temporal distribution of the hydraulic conductivity is analytically defined as a function of the induced strains. Then, the hydrogeological model is linked with the geomechanical model to simulate patterns of groundwater flow through the rock mass during cave propagation. Finally, a drainage chart is presented based on the hydrogeological simulation considering different caving stages and different system recharge due to surface inflows.

Stratigraphic framework and late Holocene history of a lacustrine beach-ridge complex: Paleoclimate archives within migrating strand promontories

This paper focuses on the physiography, stratigraphy, and age composition of a migrating strandplain promontory on Lake Michigan, discussing implied changes in alongshore sediment-transport dynamics within context of regional climate data. The Zion Beach-ridge Plain, a mainland-attached system believed to have migrated by >10 km over the past 4.5 kyrs, is partitioned into distinct physiographic zones. Its structural compartmentalization into distinct ridge sets, recognized in LiDAR-based topographic datasets and subsurface reflection geophysical records, reflects a punctuated morphodynamic development that has implications for understanding groundwater-flow patterns, wetland ecology, and coastal morphodynamic evolution. The most recent physiographic boundary within the strand dates to a high-amplitude lake-level rise event (>3 m in magnitude) that coincided with a regional shift in dominant storm-wind direction. The abrupt juxtaposition of young, high-relief dune-ridge terrain against old, low-relief wetland meadow attests to increased rates of littoral sand transport under conditions of heightened wave and current energies. Ongoing work to refine the geochronology of this and similar events is underway and stands to enhance our understanding of late Holocene coastal evolution. Strandplains are studied globally as important coastal paleoclimate archives, yet in the Great Lakes region the emphasis has been on embayed systems. While sheltered environments (e.g., bedrock-confined strandplains) foster high preservation potentials, optimal for paleohydrographic reconstructions from progradational sequences, the complex depositional architectures of strandplain promontories may provide information on open-water processes not contained within the former.

Transient ground bulge derived from a dense broadband seismic array during an aquifer step-drawdown pumping test

We deployed nine broadband seismometers within 32 m of a well where a four-hour step-drawdown pumping test was conducted at a site near Shuangxi, Taiwan in August 2018. The whole seismic array simultaneously recorded hour-long seismic signals that we interpret as ground tilt evolution during and after the pumping. Here we document data from the six seismic stations within 10 m of the boreholes to show the ground deformation closest to the pump site. Instead of ground subsidence due to groundwater over-draw as documented in many long-term and even short-term GPS and tiltmeter studies, four out of the six seismometers show ground bulge at the pumping site with radial directional tilts up to 1.0 × 10-5 rad for a drawdown of 10 m. We interpret the bulge as the dominant transient crustal response to the unloading of discharged groundwater, outpacing the minor subsidence due to reduced effective stress from reduced pore fluid head. After the pumping stopped, the ground tilt signals started to level back, though not simultaneously: some signals recorded delays up to an hour, possibly related to replenishment of groundwater from far-field or different aquifers and shallow depth hydrological heterogeneity including minor faults and fractures. We conducted seismic reflection surveys and found mostly layered structures without large fault offsets. Using an analytical solution that calculates the ground tilt due to surface load changes, we calculated the effects of unloading on ground deformation. The predicted tilt signals are in the range of 10-5 rad, the same order as the seismically derived tilts from this study. For 10 m of drawdown we estimate 10-5 to10-4 m of vertical ground uplift for this particular site. Our study demonstrates that dense broadband seismic arrays may offer a relatively less expensive and non-invasive tool to study temporal and spatial evolution of ground motions, and thus the ground water flow patterns, during pumping tests.

A simulation of the migration of a cassava contaminant plume from a processing mill into aquifers, Eku, Delta State, Nigeria

Toxic effluents from cassava processing mills through leaching and percolation are transported into groundwater, which may be detrimental to the health of humans when consumed. Our knowledge on how these toxic effluents are transported into groundwater is limited and has not received the needed attention. The objective of the study is to stimulate groundwater flow and migration pattern of cassava effluents, stimulate the impact of recharge and discharge on the fate of cassava plume migration and, lastly to suggest a remediation techniques. Groundwater modelling system (GMS) software was used for the stimulation of migration of cyanide from the surface into groundwater. The results revealed that transport of Cyanide is considerably influenced by the subsurface geology of the unsaturated zone, groundwater recharge, pumping and dispersion rates, respectively. In a well at the source, a cyanide mass of 3.5 × 105 mg was observed under increased recharge conditions for 7300 days and 7.6 × 104 mg when reduced. Increased pumping rate for 7300 days, cyanide mass of 8.8 × 104 mg was detected and it was 2.6 × 105 mg when reduced. Increased dispersion results in 2.3 × 105 mg and 3.1 × 105 mg when reduced. Of these parameters simulated, recharge has the greatest impact on the transport of cyanide. The effectiveness of using MODFLOW and MT3DMS to understand the way cyanide is transported into groundwater is fully demonstrated. The pump-and treat remediation types is recommended for groundwater resource management and planning.

Groundwater occurrence and its physicochemical properties on the northern slope of Mount Lawu, Ngawi, East Java, Indonesia

The exploitation of groundwater on the northern slope of Mount Lawu, Ngawi, East Java, Indonesia is increasing due to agricultural use. To maintain the existence and sustainability of groundwater, the first step is to know the groundwater occurrence in the area. The objective of this study is to analyze the groundwater occurrence in the study area, the groundwater flow pattern, and the physicochemical properties of groundwater such as pH, Temperature, Total Dissolved Solids (TDS), and Electrical Conductivity (EC). The research methodology involved field hydrogeological observation and analysis of data processing using the Geographic Information System (GIS). Hydrogeological observation activities involve direct observation and measurement of 4 springs, 14 deep wells, and 42 dug wells located on the northern slope of Mount Lawu. The result of this research indicates that in both shallow and deep groundwater, the pattern and groundwater flow direction are from south to north and then parallel to the flow of the Bengawan Solo River. The physicochemical characteristics of the deep well water show similarities to those of the dug well water. Based on the findings, the groundwater system in the research area can be presumably developed by only a single groundwater system or two interconnected groundwater systems.

GROUNDWATER FLOW PATTERN AROUND GONOHARJO HOT SPRING, KENDAL REGENCY, CENTRAL JAVA

The Ungaran Mountain is a stratovolcano-type volcano with a geothermal system. On the northern side of Mount Ungaran, there are hot springs located in the Gonoharjo area, Kendal Regency, Central Java, Indonesia. These hot springs appear on the mountain slopes and are very close to the surface water. This research aims in analyzing the pattern of groundwater flow with surface water flow around the springs and identifying the relationship that occurs between the springs and the nearest river flow. Analysis of the groundwater flow pattern can be determined based on groundwater level contour maps and groundwater flow maps. Such mapping can occur by plotting groundwater level data measured from 16 springs scattered on the slopes of Mount Ungaran. As a result of the measurements taken, the groundwater level ranged from 298.02 m above sea level to 818.47 m above sea level. The highest groundwater level is in the Pakis area while the lowest groundwater level is in the Boja area. The groundwater flow pattern at the study site flows from the top of the mountain and spreads to the north, northwest, west, southwest. Based on the 15 cross sections conducted, it can be identified that in general the relationship between groundwater and rivers flow in the study area is that most of the groundwater supplies surface water.

Regional groundwater flow pattern in fractured bedrock with a high-level radioactive waste repository: numerical simulation of the Xinchang site, northwestern China

Regional groundwater flow pattern in fractured bedrock with a high-level radioactive waste repository: numerical simulation of the Xinchang site, northwestern China

Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

In ancient riverbed areas, the hydro-geological conditions are extremely complex because of the cutting of ancient river channels during the sedimentary process. How to lower groundwater level in water-riched gravel-confined aquifer during deep excavation is vital for underground engineering. Groundwater flow patterns had to be understood during foundation pit dewatering. This paper presents a field case study conducted at the deep foundation pit of the Qianjiang Century City station on Hangzhou Metro Line 6, which is notable for its 52 m deep unclosed waterproof curtain. A total of 34 pumping wells were installed within the pit. During the tests, one well was subjected to a pumping well, while the others served as observation wells. The research included two sets of multi-depth pumping tests, which differed in terms of their filter lengths, aimed at investigating the flow pattern around pump wells and the roots of diaphragm walls. The study found that the use of longer filters, higher pump rates, and filters placed nearer to aquifer roofs enhances dewatering efficiency and minimizes impact on the surrounding geological environment. This paper introduces a novel concept known as the diaphragm wall–pumping well effect, which regulates the water head outside the pit and the subsidence, thereby optimizing the drawdown of the deep foundation pit with an unclosed waterproof curtain. The findings were applied in the foundation pit dewatering of Qianjiang Century City station, and the drawdown in and outside the pit was effectively controlled.

Examining the change in groundwater flow patterns: A case study from the plain area of the Baiyangdian Lake Watershed, North China

Examining the evolution of groundwater flow patterns is critical to understanding the hydrological cycle and plays an important role in the sustainable management of water resources and ecosystems. In this study, the plain area of the Baiyangdian Lake Watershed (PBW) was chosen as a typical area for severe water scarcity and ecological crisis in the North China Plain. We investigated the temporal and spatial variability in groundwater flow patterns from a holistic view of the water cycle in the PBW and explored more sustainable water resources management using multiple methods, including field surveys, historical data review, statistical analysis, and numerical groundwater modelling. The results show that the groundwater storage decreased by 494 × 108 m3 across the PBW from 1965 to 2019, while the groundwater level presented a decreasing trend for most of the period, which resulted in changes of Baiyangdian Lake and groundwater interactions. Human factors, such as groundwater extraction and water transfer projects, significantly influenced the evolution of groundwater flow patterns by generating a greater contribution of human factors to groundwater balance (54.23%) than that of climate change (45.77%). The hydrodynamic simulations imply that the interaction between groundwater and Baiyangdian Lake was dominated by groundwater recharging the river under natural conditions, and the influence depth of the interaction zone was within about 80 m underground; however, under anthropogenic disturbance, their interaction was altered to the lake recharging groundwater, with a maximum influence depth up to 135 m. Furthermore, considering the systematicity and zoning of the water cycle, we proposed a combination of different strategies, including restricted groundwater exploitation, increased water diversion and water use efficiency, and managed aquifer recharge, which could restore groundwater levels and groundwater storage over a 20-year period to realize sustainable groundwater development. This study highlights the spatiotemporal groundwater flow patterns in a changing environment and the associated hydrogeological processes and provides insights towards the development of more effective water management strategies.

Scaling of groundwater flow subject to managed aquifer recharge using injection boreholes: Physical experiments and upscaled numerical models

Managed aquifer recharge (MAR) holds great promise for solving the issue of groundwater resource depletion and quality deterioration in urban areas, but the scaling of groundwater flow patterns under MAR influence from controlled laboratory experiments to complex field scale conditions has not been fully resolved. This study applied physical and numerical groundwater flow experiments at the laboratory scale (100 m) along with ten numerical models at increasing spatial scales (100–103 m) for porous media representative of unconsolidated sand aquifers. We considered several spatial and temporal features that characterize groundwater flow patterns, such as the water table elevation, the thickness of the capillary fringe, the MAR lens geometry (defined as formed by the plume of artificially recharged water), the locations of stagnation points (defined as the points of convergence between ambient groundwater flow and injected water flow), and the groundwater travel times, which were examined at relative scales for comparison. The analysis showed that small-scale sandbox experiments overall underestimate the magnitude of the effects of MAR on groundwater flow pathways. The trends with increasing scales for these parameters were non-linear and could be fitted to power law relationships. These trends were more prominent at scales <20 times the size of the laboratory sand tank. Importantly, the heterogeneity of the sand material, as reflected by non-uniform spatial distributions of hydraulic conductivities (K) also had a major effect on the scaling of groundwater flow patterns, even for the relatively low degree of heterogeneity considered. Specifically, an increase in the average K and its standard deviation further exacerbates the scale dependency. This study provides insights into the appropriate scaling techniques to be used when applying small scale experimental results (e.g., from laboratory) to predict MAR-induced groundwater flow dynamics at larger field scales in moderately heterogeneous, unconsolidated sands.

Analisis Pola Aliran Air Tanah Di Sekitar Saluran Pembuang Pada Lahan Gambut Tropis Dengan Fungsi Lahan Pertanian

This study aims to analyze the pattern of groundwater flow around drains on tropical peatlands and to determine the effect of groundwater around drains on tropical peatlands with agricultural land functions. The research data used is primary data, namely water level, distance of each well pipe, coordinate points. In carrying out the analysis process using surfer software.The results showed that the pattern of groundwater flow around the drainage canal on tropical peatlands is that it tends to flow from the land to the drainage canal with the condition that the water level in the channel is lower than the groundwater level on the land.Besides that, from the results of the analysis carried out, it was found that the water level in the drain has an effect on the pattern of groundwater flow in tropical peatlands (agricultural land functions). The greater the difference in the height of the water level in the drainage canal (low water level condition), with the ground water level in the field (high water level condition), the pattern of groundwater flow tends to move towards the canal. However, when the water level in the channel is almost the same as the groundwater level in the field, the pattern of groundwater flow will change.

Laboratory studies of the temporal evolution process of the riparian groundwater flow system related to rainfall

Comprehensive investigations of the riparian groundwater flow system response to rainfall based on laboratory experiments and numerical simulation are presented and discussed. The 1D sand column experiment results showed that the capillary fringe of the sand sample was 25 cm, and the supporting capillary water height was about 65 cm. The 2D sandbox was constructed to investigate the changes of hydraulic heads and groundwater flow system in the hypothetical riparian zone under different initial water tables and rainfall intensities. When the initial water table was shallow, a small amount of rainfall infiltration resulted in a rapid and large rise of the water table due to the effect of capillary fringe. When the initial water table was equal to the riverbed elevation, groundwater flow pattern changed once after the rainfall infiltration. In the early rainfall period, a groundwater divide and two opposite local flow systems occurred; one flowed to the upslope unsaturated zone (counter directional local flow system), the other flowed to the river (codirectional local flow system). As the rain continued, the groundwater divide kept moving to the upslope and finally disappeared by forming a stable codirectional regional flow system. When the initial water table was lower than the riverbed, groundwater flow pattern was more complex and changed twice. At the beginning, all the rainfall infiltration recharged the thick unsaturated zone and there was only a counter directional regional flow system. When the water table rose to the riverbed, a groundwater divide and two opposite local flow systems were formed. The groundwater divide was moving to the upland and finally formed a steady codirectional regional flow system. More fine characterization of hydrological variation in a short-time scale in the riparian zone is necessary in the future.

Integration of Geological, Geochemical Modelling and Hydrodynamic Condition for Understanding the Geometry and Flow Pattern of the Aquifer System, Southern Nyírség–Hajdúság, Hungary

Geological heterogeneity impacts groundwater flow patterns, necessitating a detailed hydrogeological framework for conceptualization process of aquifer systems. This research developed a new conceptual model of detailed geologic geometry by integrating 133 well-logs, 366 hydrodynamic data and 118 water samples. As new results, systematic 3D log correlation detected four distinct hydrostratigraphic units in the Southern Nyírség–Hajdúság Groundwater Body (East Hungary). The primary aquifer was identified as an incised valley 10–13 km wide and a NE–SW strike. Logan’s approach estimated the average hydraulic conductivity of the Incised Valley Unit (IVU) at 11 m/d, higher than the other three aquifers (3.2 m/d to 4.6 m/d). The average specific capacity of wells screening the IVU is 315.6 m3/d/m, in contrast with the remaining aquifers ranging from 31.6 m3/d/m to 92 m3/d/m. Pressure–depth profiles, dynamic pressure increment and hydraulic head maps revealed recharge–discharge zones and hydraulic windows between hydrostratigraphic units. The elongated pattern on the hydraulic head map at the depth of the IVU showed the existence of a preferential path along its axis within the mapped borders of the IVU. Hydrochemical analysis revealed Ca-Mg-HCO3 water type within the primary aquifer and Na-HCO3 water type in the laterally connected aquifer. The saturation index values indicated a transition from undersaturated to supersaturated state inside the main aquifer for calcite and dolomite minerals. The correlation matrix and PCA results demonstrated that the carbonate weathering process is the main factor controlling the groundwater chemistry. This integrated approach holds significance for future applications of the regional conceptual model in water management planning, sustainable aquifer development and contaminant transport modelling. It provides essential contributions to informed decision-making and the formulation of effective strategies, ensuring the long-term availability and utilization of groundwater resources.

The role of thermokarst evolution in debris flow initiation (Hüttekar Rock Glacier, Austrian Alps)

Abstract. A rapid sequence of cascading events involving thermokarst lake outburst, local rock glacier front failure, debris flow development, and river blockage hit Radurschl Valley (Ötztal Alps, Tyrol) on 13 August 2019. Compounding effects from permafrost degradation and drainage network development within the rock glacier initiated the complex process chain. The debris flow dammed the main river of the valley, impounding a water volume of 120 000 m3 that was partly drained by excavation to prevent a potentially catastrophic outburst flood. We present a systematic analysis of destabilizing factors to deduce the failure mechanism. The identification and evaluation of individual factors reveals a critical combination of topographical and sedimentological disposition, climate, and weather patterns driving the evolution of a thermokarst drainage network. Progressively changing groundwater flow and storage patterns within the frozen sediment accumulation governed the slope stability of the rock glacier front. Our results demonstrate the hazard potential of active rock glaciers due to their large amount of mobilizable sediment, dynamically changing internal structure, thermokarst lake development, and substantial water flow along a rapidly evolving channel network.

Spatial-Temporal Patterns of Shallow Groundwater Levels in the Yellow River Delta, China

Analysis of the various hydrologic features responsible for the spatial and temporal variability in large scale subsurface systems is a critical component of water resources engineering and management. Traditionally, modeling large-scale groundwater flow patterns includes simulations with underlying parameter estimations and associated overarching assumptions. More recently, subsurface hydrologists are using empirical orthogonal function analysis to separate and quantify the primary hydrologic components contributing to observed regional and local-scale groundwater hydrodynamics. In this case study, modern spatiotemporal geostatistics plus primary hydrologic component analysis were conducted on spatially and temporally distributed groundwater levels measured in the Yellow River Delta. The results demonstrate the significant interplay between surface water hydrodynamics, overall groundwater quality, and groundwater utilization at the local scale, plus the significant impact of regional-scale aquifer recharge on groundwater level seasonal variation, largely driven by precipitation events. With increased accessibility to remote sensing data, additional research using these or similar statistical approaches to interpolate, compress, and decompose those features driving subsurface fluid-flow variability will prove to be highly beneficial to water resource engineers and managers.

Identification of Sediment Formation Based on Magnetic Content and Element Composition of Mud Volcano in Sangiran Sediment using VSM and X-Ray Fluorescence

Based on trace geological history and several studies, the Sangiran mud volcano provides insight into the geology and hydrology of the region, aquifer system in the basin, groundwater flow patterns and characteristics, rock lithology, hydrogeology condition, and saltwater trap mapping. Related to these conditions, studies were conducted on the magnetic content and composition of the major oxide compounds in the Sangiran sediments. Sample analysis was based on geochemical methods. The methods consist of frequency dependent magnetic susceptibility and vibrating sample magnetometer (VSM) analysis. Geochemical analyses using x-ray fluorescence (XRF) analysis have been conducted and various elemental grades have been determined. VSM results confirm that the magnetic content of Sangiran sediments is partly dominated by Fe (17.66 percent) contained in hematite (Fe2O3). At the same time, the samples of Sangiran sediment were enriched by Si, Fe, Al, Ca, Cl, Ti, and K according to XRF measurements. The samples exhibited the highest Si and Fe concentrations in samples T1 (Si is 29.48 percent and Fe is 13.66 percent) and T7 (Si is 24.95 percent and Fe is 12.01 percent). Meanwhile, in the T4 sample, the highest concentrations were Si and Ca, 23.45 percent and 13.45 percent, respectively. Retrieved from the magnetic susceptibility measurement, this paper confirm that Fe content is one of the components of volcanic ash in the Sangiran sediment.DOI: 10.17977/um024v8i12023p009