Basement Structures Research Articles

Application of Euler and Werner deconvolution techniques in delineating tin deposit in Okeso area, Southwestern, Nigeria

The Okeso pegmatites field was evaluated using magnetic method within abandoned mining site close to the southeastern region of Ojoku area. The study aims to delineate, identify geological boundaries and determine depth of tin deposits in the area. The acquired magnetic data was enhanced with the combination of 3D Euler and Werner deconvolution methods. Five magnetic profiles were selected and carried out on the residual anomalies around the abandoned mine site at Okeso with three of the profile lines were in the NW-SE direction and two in the NE-SW direction. The residual magnetic anomalies showed the magnetic susceptibilities of ≤ 4.5118 × 10−3 nT in the ore bearing pegmatite within the basement rocks. Results from profiles of Werner deconvolution identified some shallow tectonic structures like fractures, pegmatites and faults which are capable of hosting metallic tin deposits. The depth to the magnetic source varies from a minimum to a maximum of 300 m to 1200 m below the subsurface in all selected profiles, suggesting the shallow nature of the magnetic source in the area. Additionally, the dip angle ranges from 5.60 to 81.20, potentially attributed to Pan-African shallow structures according to the contact model. Solutions obtained from the structural index of contact and dyke reveals the presence of dyke formation and boundaries which separate rocks from one another. The trend of the lineaments/ fractures which were likely established during the Pan-African orogeny is dominant in the NE-SW direction, conforms with the trends obtained for basement structures in previous studies. Depth range produced by 3D Euler deconvolution is from 50 - 1000 m for all the lineaments. This gives an insight of approximate depth range of all the lineaments/ fractures across the whole map in the study area unlike, Werner deconvolution which is profile biased. The identical signature from all profiles implies that the tin deposit is relatively uniform, extending to a great depth in the area. This represents economically viable quantity and makes it a worthy target for investors.

Application of Euler and Werner deconvolution techniques in delineating tin deposit in Okeso area, Southwestern, Nigeria

The Okeso pegmatites field was evaluated using magnetic method within abandoned mining site close to the southeastern region of Ojoku area. The study aims to delineate, identify geological boundaries and determine depth of tin deposits in the area. The acquired magnetic data was enhanced with the combination of 3D Euler and Werner deconvolution methods. Five magnetic profiles were selected and carried out on the residual anomalies around the abandoned mine site at Okeso with three of the profile lines were in the NW-SE direction and two in the NE-SW direction. The residual magnetic anomalies showed the magnetic susceptibilities of ≤ 4.5118 × 10−3 nT in the ore bearing pegmatite within the basement rocks. Results from profiles of Werner deconvolution identified some shallow tectonic structures like fractures, pegmatites and faults which are capable of hosting metallic tin deposits. The depth to the magnetic source varies from a minimum to a maximum of 300 m to 1200 m below the subsurface in all selected profiles, suggesting the shallow nature of the magnetic source in the area. Additionally, the dip angle ranges from 5.60 to 81.20, potentially attributed to Pan-African shallow structures according to the contact model. Solutions obtained from the structural index of contact and dyke reveals the presence of dyke formation and boundaries which separate rocks from one another. The trend of the lineaments/ fractures which were likely established during the Pan-African orogeny is dominant in the NE-SW direction, conforms with the trends obtained for basement structures in previous studies. Depth range produced by 3D Euler deconvolution is from 50 - 1000 m for all the lineaments. This gives an insight of approximate depth range of all the lineaments/ fractures across the whole map in the study area unlike, Werner deconvolution which is profile biased. The identical signature from all profiles implies that the tin deposit is relatively uniform, extending to a great depth in the area. This represents economically viable quantity and makes it a worthy target for investors.

Influence of subtle inherited basement structures on thin-skinned thrust systems: The Caledonian Thrust Front in Lapland (CaTFLap)

Thin-skinned fold-thrust belts are defined by an extensive detachment surface, “the sole thrust’. The sole thrust is typically assumed to be sub-planar beneath the fold-thrust belt. The model of a planar sole thrust and, by inference, planar basement is often applied rather uncritically, whereas experimental and field studies show that basement topography is not only varied but crucial for the geometrical and kinematic evolution of fold-thrust belts. Basement topography controls on the thrust dynamics remains the least well understood parameter in fold-thrust belts, and more case studies are needed to underpin further understanding. We present field evidence from the well-exposed Caledonian Thrust Front in Lapland, showing the influence of inherited, orogen-perpendicular basement structures on the subsequent structural evolution of the Caledonian sole thrust and its underlying sedimentary rocks. Inherited orogen-perpendicular basement structures created open corrugations in the foreland that directed thrust allochthons and controlled the geometry and strain state of the sole thrust and associated rocks. We propose that even relatively small-scale structures can have a significant control on the geometry and strain state of an evolving thrust system, and that variations in thrust geometries are not simply explained by inversion or coincidental heterogeneous internal thickening (imbrication) of thrust-related units.

Tomographic imaging of South Rewa basin, Central India: Implications of Gondwana rifting and Late Cretaceous volcanism

We have imaged thick (3.0–5.0 km) sub-trappean Gondwana sediments deposited in a typical rift-environment of the south Rewa basin in Central India masked by Deccan basalts. The basalts intrude through the basin forming several dykes, sills, and other intrusions along with large-scale undulations of the basement showing complex geology and tectonic settings due to Late Cretaceous volcanism (~65 Ma). To delineate complex subsurface geological structures and understand the tectonic settings, we use long-offset seismic reflection data along the N-S trending 127 km Kuvari-Shahdol profile of the basin. The conventional stack and pre-stack time migration techniques fail to image the complex subsurface structures dominated by steeply dipping faults. The steeply dipping faults with small-scale structures are influenced by strong lateral and vertical velocity variations that cause problems in imaging the basin. Hence, a robust tomographic inversion with pre-stack depth migration technique is adopted to image fine-scale subtle subsurface geological structures with smooth velocity variations. The tomographic velocity model and pre-stack depth migration seismic image could decipher basaltic trap thickness, numerous dyke intrusions, alternate horsts and grabens with deposition of thick hydrocarbon-bearing sub-trappean Gondwana rocks along with the basement configuration. The deep basinal faults with highly distorted basement structures represent the intense tectonic activity of this Gondwana rift-basin. The deep-seated hydrocarbon reservoir is discovered with an excellent trapping mechanism forming both pre-rift and syn-rift settings of the rift-basin. The seismic image is further constrained and corroborated by the inversion of residual Bouguer gravity anomaly data to obtain corresponding density model derived from tomographic velocity model. The large basement faults, horsts and grabens, several intrusives like dyke, sill, laccolith, and thick sub-trappean Gondwana formations with Deccan trap cover indicate complex geology and tectonic settings of south Rewa basin forming the Late Cretaceous Volcanic Province of India.

Reconstructing the Evolution of Foreland Fold‐And‐Thrust Belts Using U‐Pb Calcite Dating: An Integrated Case‐Study From the Easternmost Jura Mountains (Switzerland)

AbstractThis case‐study from the Jura Mountains in the foreland of the European Alps demonstrates how the coupling of subsurface analysis and U‐Pb carbonate dating can provide absolute timing constraints and shortening rate estimates of fold‐and‐thrust belts. It is confirmed that the initial Late Cenozoic foreland deformation driving the formation of the easternmost Jura Mountains in Switzerland was predominately thin‐skinned with contractional deformation largely restricted to the Mesozoic succession above a sub‐horizontal basal décollement. Thereby, the localization and structural style of related deformation structures was strongly guided by the characteristics of underlying Late Paleozoic half grabens. The main thin‐skinned thrust front formed at ∼12 Ma, followed by further deformation in the hinterland and locally continued foreland‐directed thrust propagation. The major deformation zones exposed at surface were established at ∼8 Ma but shortening continued until at least ∼4 Ma. Thick‐skinned contraction associated with the inversion of basement structures only played a subordinate role during the latest deformation phase after 8 Ma. Based on cumulative shortening values derived from balanced cross sections, our U‐Pb ages of syn‐tectonic calcite slickenfibres allow to estimate thin‐skinned deformation rates for the easternmost Jura Mountains between ∼0.9 and ∼0.1 mm/year, decreasing toward the eastern tip of the arcuate belt. Moreover, deformation rates seemingly decreased over time with rates of initial thin‐skinned thrusting being significantly higher than the later deformation north of the main thrust front. These new findings from a classical foreland setting highlight the potential of integrating U‐Pb dating in regional fold‐and‐thrust belt investigations elsewhere.

Human-Altered Water and Carbon Cycles in the Lake Yangzong Basin since the Yuan Dynasty

Due to the dual influence of climate change and human activities, the water cycle patterns in the lakesheds of the Yunnan karst plateau are undergoing significant changes, leading to increasingly prominent ecological issues. In the history of Lake Yangzong, an artificial water-diversion channel was excavated, altering the lake basin structure. Human activities have intensified, posing severe challenges to water resource supply and water security in recent decades. To investigate the significant increase in human activities, the temporal and phase changes, and the resulting transformation of the water and carbon cycles in the Lake Yangzong basin, we applied X-ray fluorescence spectroscopy (XRF) to scan elements continuously in a 10.2 m sediment core from this lake. By combining correlation analysis, principal component analysis (PCA), core chronology, and total organic carbon (TOC) content, we reconstructed the historical sequence of geochemical element contents in the Lake Yangzong catchment over the past 13,000 years. The results show that PC1 and PC2 contribute 78.4% and 10.3%, respectively, suggesting that erosion intensity is the main factor influencing the lake sedimentation process. From 13,400 to 680 cal a BP (calibrated years before the present), the sedimentation process in Lake Yangzong was mainly controlled by climatic conditions, with vegetation degradation during cold periods and relatively high erosion intensity in the watershed. During the Yuan dynasty, a province was established by the central government in Yunnan, promoting settlement and attracting a large number of immigrants from other provinces to Yunnan. Human activities in the Lake Yangzong basin began to intensify, surpassing natural changes and becoming the dominant force influencing the sedimentation process. In the Ming and Qing dynasties, the population and cultivated land area in Yunnan further increased, resulting in the significant exacerbation of erosion and soil loss in the watershed due to vegetation destruction. In the year 1388, the Tangchi Canal was excavated, transforming Lake Yangzong to an outflow lake, causing Ca2+ to be lost through the Tangchi Canal and preventing the formation of precipitation due to oversaturation. The research results indicate that human activities in the Lake Yangzong area have intensified since the Yuan dynasty, leading to increased erosion intensity. The excavation of the outflow canal transformed Lake Yangzong from an inland lake basin into an outflow state, simultaneously generating a significant transformation in the water and carbon cycling patterns in the watershed.

The Impact of Urban Land Use Changes on the Morphology of the New Calabar River Catchment, Port Harcourt Metropolis, Nigeria

The New Calabar River catchment has experienced significant alterations in land use and land cover patterns due to the fast population growth in Port Harcourt. This research investigated the influence of urban land use change on the morphological structure of the New Calabar River basin, which is experiencing rapid urbanization in Rivers State. The research utilized a combination of primary and secondary data sources, specifically satellite imagery and field measurements of the hydro-geomorphic channel's breadth and depth. The findings indicated a significant rise in urbanization, resulting in the encroachment upon various land uses, including water bodies, farmlands, dense forests, and wetlands. Moreover, correlation and regression analysis revealed a significant positive link between channel morphology, discharge, and urbanization index. Therefore, it can be argued that the urbanization index and discharge are crucial in determining the river channel's current channel form and size features. The study also demonstrated a positive correlation between discharge and channel dimensions, including width and depth. The stream channel has experienced an expansion in reaction to the modification of the natural soil caused by urbanization, leading to changes in the stream flow regime. Additionally, it has been observed that the segment of the New Calabar River that encompasses urbanized regions tends to have a comparatively more significant cross-sectional channel. Incorporating urbanization analysis and its impact on morphology has facilitated the implementation of diverse geospatial analyses and sustainable watershed management in the basin.

Geophysical insights into basement faults influencing basin evolution: A case study from Tennant Creek Block, North Australian Craton

Geophysical interpretation and modelling of the poorly exposed Proterozoic basement rocks of the Tennant Creek Block in the North Australian Craton elucidated the distribution, location, connectivity, and overprinting relationships of regional faults. The prominent structural grain within the basement comprises west-northwest-striking faults that commonly bound geophysically defined domains of the Warramunga Formation and felsic plutons of the Tennant Creek Supersuite. Constrained by seismic reflection data, forward models of gravity and magnetic data identified several faults as major structures that link into a shallow south-dipping structure at approximately 20 km depth. The modelling also reveals a 20 km wide and 14 km southward deepening half-graben bounded by a northeast dipping normal fault. The half-graben forms a sub-basin filled with the Ooradidgee Group at the top of the basement stratigraphy. The west-northwest-trending structural grain of the basement is not reflected in the Tomkinson Creek Group in the overlying younger basin. The younger basin has dominant north-oriented faults and basement highs. This suggests basement structures had limited influence in controlling the evolution of younger basins in this region. Our approach has wider relevance, addressing similar challenges encountered in other cratonic areas globally, such as India and Africa, where sedimentary cover obscures critical aspects of basement architecture and tectonic evolution. This underscores the broader significance of our methodology in advancing the understanding of Precambrian terranes.

METHODS FOR 3D INVERSION OF GRAVITY DATA IN INDENTIFYING TECTONIC FACTORS CONTROLLING HYDROCARBON ACCUMULATIONS IN THE EL ZEIT BASIN AREA, SOUTHWESTERN GULF OF SUEZ, EGYPT

The Gebel EL-Zeit area in the southwestern Gulf of Suez, Egypt, is an area with a significant hydrocarbon potential in sedimentary basins, so that the three-stage inversion method was proposed for the Bouguer anomalies observed therein. Salt diapirs obscured the deep structure of the main central El-Zeit basin; hence, this method was implemented to overcome challenges in 3D seismic modeling. Our study included direct and inverse parameterization sequences that involved analyzing the inputs and outputs within trial-and-error initiations and inverse estimations to assess whether and how much the constraining parameters used in the calculations could achieve the intended aim. Data reduction, filtering, optimization, and constraint assumptions were used to determine the minimal set of density model parameters needed to set limits on the acceptable range of density contrasts that are required to study the basement depths, swells, troughs, faulting/folding and intra-sedimentary structures, and for direct modeling aimed at creating a simple model to save time. The thirteen constrained wells with a total depth ranging from shallow to deep were not involved in direct modeling but provided quality control over the graphical display of the inverse results for the entire study area. Moreover, many parameter constraints were inverted to regulate the way the calculated data are related to the model’s solution that allowed us to determine which inversion trial provided the best parameterization sequence and, therefore, yielded the most appropriate solution for the depth-density model which is approximating reality with a minimal computation error in the study area.

The North Sea rift basement records extensional collapse of the Caledonian orogen

Our knowledge of crystalline basement rocks flooring continental rift basins, rifted margin deposits, and foreland basins is poor, yet important for understanding basin evolution, crustal heat production, petroleum maturation, and for offshore mineral exploration. Using the northern North Sea rift as an example, we demonstrate how modern broadband seismic data can be utilized to unravel basement lithology and structure at a previously unprecedented level of detail. In our case study, we have discovered a pre-rift Caledonian basement with a folded structural pattern very similar to Devonian collapse-related structures onshore Western Norway. The data indicate that the collapse-generated Caledonian infrastructure extends >100 km into the northern North Sea, defining a wide zone of Caledonian crust that turned hot and mobilized vertically by upright folding and detachment faulting during the post-collisional stage. This extensive post-orogenic thermally induced collapse makes the south Scandinavian Caledonides unique among Phanerozoic orogens.

Structural Interpretation of the Basement beneath the Southern Desert of Iraq based on Aeromagnetic Data.

The Southern Desert of Iraq is located on the stable part of the Arabian Platform. The area has a considerable thickness of Phanerozoic sediments overlying a basement. The basement has neither been seismically imaged nor drilled. Accordingly, magnetic method can help identify and map deep structure of the basement. The aeromagnetic data are used to determine the structure and approximate depth of the basement. We have used the combined results of the Tilt derivative and Phase Preserving Dynamic Range Compression (PPDRC) methods to qualitatively delineate the main basement structures and then used the Source Parameter Imaging (SPI), Tilt-depth and finite SPI (FSPI) methods to determine basement depths. The qualitative interpretation of the Tilt derivative and PPDRC methods identifies three N-S to NE-SW trending linear negative anomalies that could represent extensional grabens in the basement surface. These grabens divide the basement into three blocks, the NW block, central block, and SE block. The magnetic anomalies over the basement blocks suggest the NW and Central blocks are cut by a set of N-S to NNW-SSE and NE-SW faults. Depth estimation methods over the uplifted blocks have minimum depths of between 4 km to 5 km, while over the graben the depths range from 7 km to in excess of 12 km. The FSPI method, unlike the SPI and TD methods that use an infinite depth source body, gives depths generally deeper by up to 1.1 km if the assumed Curie point depth is at 21 km. A more realistic Curie point depth of 32 km is used in the final interpretation model. These inferred basement blocks, grabens and sub-basin structures agree in a general way with the regional structures associated with the Arabian Peninsula and could provide an important framework for developing future hydrocarbon exploration strategies of the Southern Desert.

Innovative Three-Row Pile Support System of Ultra-Deep Foundation Pit and Cooperative Construction Technology with Basement for High-Rise Tower Structures

This paper proposes the structural design and calculation model of stepped three-row pile and verifies its antioverturning and antisliding stability, based on the Xinghe Yabao deep foundation pit project in Shenzhen, China. The three-row pile model is constructed using finite element software, and the force and deformation of the piles are analyzed. The influence of the direction of the prestressing anchors on the support effect of the three-row pile is investigated by simulating the prestressing anchors in three directions: oblique, horizontal, and vertical. The results show that the combined support effect of the oblique anchor and the three-row pile is the most effective, resulting in the smallest deformation, followed by the horizontal anchor, and the vertical anchor produces the largest deformation. Finally, the innovative construction method of the three-row pile removal and the basement top-down construction method is proposed. The three-dimensional model of the tower building and the basement is established by the finite element software to simulate the structural grading load and the cooperative construction of the supporting structure and the basement structure. The research results have greater engineering application value and significant economic benefits, which could provide reference and guidance for the design and construction of deep foundation pits in similar projects.

An updated chronostratigraphic framework for the Cenozoic sediments of southeast margin of the Tibetan Plateau: Implications for regional tectonics

As one of the most important accommodation zones during the India-Asia collision, the southeast margin of the Tibetan Plateau (SEMTP) is characterized by many large-scale strike-slip faults, a regional low-relief relict that has been deeply incised by several continental scale rivers that originate from central Tibet, and numerous plant and vertebrate fossil biotas residing in Cenozoic sedimentary basins. Therefore, the SEMTP not only provides a meaningful constraint on the geodynamic evolution of the Tibetan Plateau, but also serves as an exemplar to understand the various interactions among surface uplift, drainage network reorganization, climate change, and biodiversity. Precise dating of Cenozoic sediments in the basins of the SEMTP is crucial for understanding these processes. Previously, the geochronologic framework of Cenozoic sediments in the SEMTP largely relied on fossils and regional stratigraphic correlations, which often involved circular reasoning and large uncertainties. In the past two decades, high-resolution magnetostratigraphy, detrital zircon geochronology, and isotopic dating of interbedded tephra layers have been carried out on SEMTP Cenozoic sedimentary basins in Yunnan and eastern Xizang provinces, SW China. Using these new data, we build a revised chronostratigraphic framework for Cenozoic sediments in SEMTP, and use this updated temporal framework to contextualize regional tectonics and climate change. The new chronostratigraphic framework shows that (1) many of the “Neogene” sedimentary basins based on plant fossils and regional lithostratigraphic correlation in the SEMTP were actually formed in the late Eocene and early Oligocene; (2) most of the Paleogene sedimentary successions in the SEMTP ended at the late Eocene-early Oligocene and were unconformably overlaid by Middle-Late Miocene sediments. Oligocene-Early Miocene sediments are often regionally absent. Sedimentary structures within the basin successions show that Paleogene basins were generally formed in compressional settings while the Late Miocene basins were mostly developed in extensional settings. The new chronostratigraphic framework, together with analyses of sedimentary basin structures, suggests that the SEMTP began to experience crustal shortening early in the India-Asia collision (~50 Ma), producing Paleogene sedimentary basins and giving rise to the subsequent widespread surface uplift and regional erosion in the Oligocene-Middle Miocene. Tectonic inversion from compression to extension since the Middle Miocene precludes significant uplift of the SEMTP after this time, which may be related to geodynamic changes in the evolution of the Tibetan Plateau.

Lefkos Shear Zone of Karpathos, Greece (SE Aegean): Pleistocene to recent transtensional forearc basin and paleoseismicity

Pleistocene–recent transtensional forearc basins and associated island uplift could be driven by sinistral–oblique convergence along the eastern Hellenic subduction zone, Greece, or by simultaneous trench retreat attributable to subduction of Permo-Triassic Tethyan lithosphere. Structural mapping and basin analysis of the Lefkos Basin, Karpathos indicate deformation best related to oblique trench retreat in which Karpathos drifts southeastward more slowly than Rhodes. Lefkos Basin, perched on a corner of the offshore Karpathos Basin, comprised two Early Pleistocene marine sub-basins developed under northwest extension. Unusually long-wavelength hummocky cross-stratification (>10 m) and clinoforms (15–20 m high) constitute distinctive marker facies. Facies architecture reflects inter-related fault-controlled subsidence, syn-depositional uplift/tilting, glacioeustacy, and fan-delta-lobe avulsion. A 230U/234Th coral age of ∼600 ka and a deer mandible date a Middle Pleistocene transition to southwestward fan-delta progradation and basin uplift. Following ∼0.5 Ma fan-delta-plain deposition, the Lefkos Slide dropped a ∼3.7 km2 coastal plain. Subsequent steep north–south dextral–normal faults dominate Lefkos Basin, with subordinate steep east–west sinistral–normal and northeast-trending normal–oblique faults. Faults signify wrench domination based on their steepness, rare slip indicators, slip reversals and co-genetic upright isoclinal folds. These structures are integral to a forearc-scale dextral–normal shear zone, the Lefkos Shear Zone, an active crustal discontinuity spanning the southeastern forearc from eastern Crete through Kasos–Karpathos to Rhodes. Vertical coherence exists between upper-crustal dextral–normal shear in the Lefkos Shear Zone, crustal seismic anisotropy and deeper mantle processes. Hydraulic fractures, fluid-expulsion pipes, and ruptured cobbles record intermittent significant seismicity (Mw ≥5–6) that permeated the entire Lefkos basin fill spanning ∼2 million years, ultimately involving Late Roman–Early Byzantine archeological remains through ∼1000 years ago. This study encourages re-evaluation of seismic, landslide and tsunami hazards in the sector of the Hellenic forearc surrounding the Lefkos and Karpathos Basins.

A Unified Approach for the Calculation of Different Sample-Based Measures with the Single Sampling Method

This paper explores two sample-based methods for analysing multistable systems: basin stability and basin entropy. Both methods rely on many numerical integration trials conducted with diverse initial conditions. The collected data is categorised and used to compute metrics that characterise solution stability, phase space structure, and system dynamics predictability. Basin stability assesses the overall likelihood of reaching specific solutions, while the basin entropy measure aims to capture the structure of attraction basins and the complexity of their boundaries. Although these two metrics complement each other effectively, their original procedures for computation differ significantly. This paper introduces a universal approach and algorithm for calculating basin stability and entropy measures. The suitability of these procedures is demonstrated through the analysis of two non-linear systems.

Modeling of kappa factor using multivariate adaptive regression splines: application to the western Türkiye ground motion dataset

AbstractThe recent seismic activity on Türkiye’s west coast, especially in the Aegean Sea region, shows that this region requires further attention. The region has significant seismic hazards because of its location in an active tectonic regime of North–South extension with multiple basin structures on soft soil deposits. Recently, despite being 70 km from the earthquake source, the Samos event (with a moment magnitude of 7.0 on October 30, 2020) caused significant localized damage and collapse in the Izmir city center due to a combination of basin effects and structural susceptibility. Despite this activity, research on site characterization and site response modeling, such as local velocity models and kappa estimates, remains sparse in this region. Kappa values display regional characteristics, necessitating the use of local kappa estimations from previous earthquake data in region–specific applications. Kappa estimates are multivariate and incorporate several characteristics such as magnitude and distance. In this study, we assess and predict the trend in mean kappa values using three–component strong–ground motion data from accelerometer sites with known VS30 values throughout western Türkiye. Multiple linear regression (MLR) and multivariate adaptive regression splines (MARS) were used to build the prediction models. The effects of epicentral distance Repi, magnitude Mw, and site class (VS30) were investigated, and the contributions of each parameter were examined using a large dataset containing recent seismic activity. The models were evaluated using well–known statistical accuracy criteria for kappa assessment. In all performance measures, the MARS model outperforms the MLR model across the selected sites.

Rigid Frame Structure Analysis of Wyndham Hotel Building Palembang

A building that is sturdy, strong, secure, and effective must be designed according to building criteria from all structrural components, starting from columns, beams, floor plates, stairs, foundation, excavations, and basement structures. To build quality that meets the criteria from all aspects. Especially the building under study is a high level building that uses a rigid frame structure where the structure is a rigid connection that connect horizontal beams as well as vertical columns then connected to a plane. And all of this works together so that it is likely that this building meets the criteria for multi-story buildings and guarantees the strength of the building structure to meet its functional aspects.

Collective dynamics of coupled Lorenz oscillators near the Hopf boundary: Intermittency and chimera states.

We study collective dynamics of networks of mutually coupled identical Lorenz oscillators near a subcritical Hopf bifurcation. Such systems exhibit induced multistable behavior with interesting spatiotemporal dynamics including synchronization, desynchronization, and chimera states. For analysis, we first consider a ring topology with nearest-neighbor coupling and find that the system may exhibit intermittent behavior due to the complex basin structures and dynamical frustration, where temporal dynamics of the oscillators in the ensemble switches between different attractors. Consequently, different oscillators may show a dynamics that is intermittently synchronized (or desynchronized), giving rise to intermittent chimera states. The behavior of the intermittent laminar phases is characterized by the characteristic time spent in the synchronization manifold, which decays as a power law. Such intermittent dynamics is quite general and is also observed in an ensemble of a large number of oscillators arranged in variety of network topologies including nonlocal, scale-free, random, and small-world networks.

Structure of the Plio-Quaternary coastal aquifer (Mediterranean Basin, Tunisia): insights from gravity and seismic analysis

This research paper presents an investigation of an aquifer structure using a combination of gravity and seismic analyses, calibrated by hydrogeological data. This work illustrates how crucial it is to study geological structures and fault networks as preliminary work to understand water- and pollutant-flow systems and aquifer vulnerability, especially with the increased frequency of drought events and climate change pressures. A Plio-Quaternary coastal northeastern aquifer in Tunisia was chosen as the study case. First, a hydrogeological approach was performed using water wells, and piezometer data showed an important fluctuation in the piezometric level and a notable depression in the piezometric surface observed in the southern part of the study area. Secondly, gravity data were analysed and calibrated using a seismic profile. The results demonstrated the presence of shallow NE–SW faults less than 300 m below the region's principal wadis, as well as deeper faults of varying depths (from 400 to 2600 m) that influence the basin structure, aquifer geometry and resulting water flow. The combination of these approaches revealed that the variations in the aquifer thickness, piezometric surface depression zones and groundwater flow are mainly controlled by shallow and deep geological structures and their tectonic reactivation.

Land subsidence along the Beijing-Tianjin high-speed railway before and after the South-to-North water diversion project with multi-source monitoring datasets

The development of land subsidence has seriously affected the safe operation of Beijing-Tianjin high-speed railway. The South-to-North Water Diversion Project Central Route (SNWDP-CR) was officially put into operation in December 2014. It has changed the water supply pattern in Beijing and provided conditions for reducing groundwater exploitation and controlling land subsidence. In this paper, the time-series interferometric data, in situ monitoring data of recent 20 years and the basic geological datasets are combined to compare and analyze the changes of groundwater level, land subsidence and the main subsidence layers along the Beijing-Tianjin high-speed railway before and after the SNWDP-CR. The effects of the environment of Quaternary sedimentary, groundwater exploitation and soil deformation of different lithology on land subsidence along the high-speed railway under the background of new water conditions are revealed. The main conclusions are as follows: 1) The serious land subsidence area along the Beijing-Tianjin high-speed railway always concentrated in the section of DK11-DK23. After the operation of SNWDP-CR, the land subsidence along the railway generally showed a slowing trend. The maximum subsidence rate was reduced from 80 mm/yr to 49 mm/yr. The length of subsidence rate that more than 50 mm/yr of the section was reduced from 8.0 km to 0 km. 2) The groundwater level of different aquifer groups along the Beijing-Tianjin high-speed railway rose and declined before and after the SNWDP-CR. in eastern part of the plain, the groundwater level of each aquifer group has changed from a continuous decline (range 0.13–1.82 m) to a gradual rise (range 0.45–1.87 m) since 2017. However, in the southeast of the plain, the groundwater level still showed a continuous decline trend, with an average annual decline of 1.2–1.8 m. 3) From 2006 to 2019, the subsidence of the first, second and third compression layer group along the railway accounted for 2.71%, 28.29% and 69%, respectively. The third compression layer group (monitoring layer 94–182 m) had the largest subsidence proportion and was the main subsidence layer. 4) The land subsidence along the Beijing-Tianjin high-speed railway is controlled by the basement structure. The difference of groundwater exploitation intensity led to differences in the spatial distribution of land subsidence along the railway. The subsidence of the soil layer below the bearing layer (about 50 m) of the high-speed railway pile foundation exhibited the characteristics of viscoplastic or viscoelastic plasticity deformation. This section of strata is a key layer that needs to be considered for land subsidence control along the Beijing-Tianjin high-speed railway in the future.