Buried Features Research Articles

This study evaluates the potential of Unmanned Aerial Vehicle-based Ground-Penetrating Radar (UAV-GPR) for identifying buried features related to a suspected World War II (WWII) hiding place near Bornerbroekseweg, the Netherlands. The survey area is an active farmland field with limited surface indicators and partially documented historical significance. A total of six UAV flight lines and four ground-based GPR paths were conducted to cover the site. Subsurface anomalies were identified at depths between approximately 0.2 and 1.5 m. In particular, Flight 6 revealed a near-surface reflection at 0.2–0.4 m, whereas Flight 4 showed a deeper horizontal anomaly at around 1.2–1.5 m. Ground-based Path 3 supported these findings with continuous horizontal reflections distinct from natural stratigraphy. The integration of UAV and ground-based data enabled full-site coverage and localized resolution, supporting the identification of areas warranting further archaeological investigation. The results demonstrate the applicability of UAV-GPR for non-invasive prospection in rural historical sites with uncertain spatial records and suggest its value for informing targeted excavations.

Amino acid sequence-based IDR classification using ensemble machine learning and quantum neural networks.

ABSTRACTKalehisar Archaeological Site, located near Mahmudiye Village in the Alaca district of Çorum, provides important insight into the Anatolian Seljuk period and 13th–14th century settlements in Central Anatolia. The main objective of this study is to determine the location and depth of possible buried archaeological remains within the archaeological site. This approach not only guides future excavations but also contributes to a more comprehensive understanding of settlement patterns and architectural practices during the Seljuk period. To achieve this, a comprehensive geophysical survey was conducted, employing magnetometry, electrical resistivity tomography and ground penetrating radar methods. Spectral analysis was used to interpret magnetic anomalies and identify potential buried features. Ground penetrating radar measurements provided high‐resolution subsurface imaging, allowing for the detection of fine‐scale stratigraphic variations and potential shallow buried remains. Electrical resistivity tomography helped identifying subsurface structures with contrasting resistivity down to 10‐m depth. Integrated geophysical results revealed wall continuations extending from the excavation area, alongside other buried features such as ceramic/pottery kilns and a possible mosque in a few depths from the surface. These findings are consistent with Seljuk‐era settlements and can aid future excavations by optimizing resources and preserving archaeological integrity.

Urban expansion in coastal areas involves infrastructure development, industrial growth, and mining activities. These coastal environments face various environmental and geological hazards that require geo-engineers to devise solutions. An integrated geophysical approach aims to address such complex challenges as sea level rise, sea water intrusion, shoreline erosion, landslides and previous anthropogenic activity in coastal settings. In this study, the proposed methodology involves the systematic application of geophysical methods (FDEM, 3D GPR, 3D ERT, seismic), starting with a broad-scale survey and then proceeding to a localized exploration, in order to identify lithostratigraphy, bedrock depth, sea water intrusion and detect anthropogenic buried features. The critical aspect is to leverage the unique strengths and limitations of each method within the coastal environment, so as to derive valuable insights for survey design (extension and orientation of measurements) and data interpretation. The coastal zone of Throrikos valley, Attica, Greece, serves as the test site of our geophysical investigation methodology. The planning of the geophysical survey included three phases: The application of frequency-domain electromagnetic (FDEM) and 3D ground penetrating radar (GPR) methods followed by a 3D electrical resistivity tomography (ERT) survey and finally, using the seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW). The FDEM method confirmed the geomorphological study findings by revealing the paleo-coastline, superficial layers of coarse material deposits and sea water preferential flow due to the presence of anthropogenic buried features. Subsequently, the 3D GPR survey was able to offer greater detail in detecting the remains of an old marble pier inland and top layer relief of coarse material deposits. The 3D ERT measurements, deployed in a U-shaped grid, successfully identified the anthropogenic feature, mapped sea water intrusion, and revealed possible impermeable formation connected to the bedrock. ERT results cannot clearly discriminate between limestone or deposits, as sea water intrusion lowers resistivity values in both formations. Finally, SRT, in combination with MASW, clearly resolves this dilemma identifying the lithostratigraphy and bedrock top relief. The findings provide critical input for engineering decisions related to foundation planning, construction feasibility, and preservation of coastal infrastructure. The methodology supports risk-informed design and sustainable development in areas with both natural and cultural heritage sensitivity. The applied approach aims to provide a complete information package to the modern engineer when faced with specific challenges in coastal settings.

Abstract With advancements in the semiconductor industry, the complexity of three‐dimensional (3D) nanostructures becomes higher with continuously decreasing feature sizes. In order to monitor the processing steps, it is crucial to accurately determine the critical dimensions and composition of these nanostructures. Early detection of production malfunctions is crucial for reasonable production yields, as even minor imperfections can heavily impede device performance. Grazing X‐ray fluorescence spectroscopy methods are non‐destructive and element‐specific methods with high sensitivity for nanostructured surfaces. They enable the quantification and localization of elements within the sample, with information depths sufficient also for buried features. Such measurements can be utilized to reconstruct the shape and size of nanostructure features, with simulated data based on finite element method (FEM) Maxwell calculations. However, the computation time of FEM calculations poses a challenge (especially in the X‐ray energy regime), prolonging the reconstruction process and making it impractical for the characterization of multiple samples. To address this issue, a neural network‐based approach is adopted to replace the time‐consuming FEM‐based forward calculations. In this study, the feasibility of utilizing neural networks for nanostructure reconstruction is demonstrated on various nanostructures. The discrimination limit for different model parameters is assessed and compared against conventional FEM calculation results.

An integrated geophysical survey, Seismic Refraction Tomography (SRT), Ground Penetrating Radar (GPR), and Electrical Resistivity Tomography (ERT), was carried out at the UNESCO World Heritage site of Saqqara, Giza, Egypt, as part of the Cairo University’s ongoing exploration project (Phase II). The primary objective of this survey was to detect and map any subsurface archeological features, such as tombs, within the study area. These geophysical methods were selected for their rapid, non-invasive nature, offering a cost-effective alternative to conventional excavation and trenching techniques. By providing valuable insights into the subsurface without disturbing the integrity of the site, the survey contributes significantly to archeological research. Each geophysical method provides unique insights: SRT data distinguished a shallow sandstone layer P-wave velocity (Vp = 400–1100 m/s) above a deeper limestone bedrock (Vp: 1200–1900 m/s), with low-velocity anomalies suggesting potential voids or chambers. GPR profiles detected linear features, likely walls or paths, alongside amplitude anomalies and low-amplitude anomalies suggesting chambers or rooms filled with high-conductive materials like clays and mud bricks. ERT data revealed high-resistivity limestone zones and low-resistivity anomalies suggestive of filled with conductive materials like clays or mud bricks. The integrated approach identified three prominent anomalies A-1, A-2, and A-3 with consistent signatures across datasets: A-1 as a probable room filled with conductive material; A-2, a low-resistivity, low-velocity hall surrounded by sediments; and A-3, a subsurface chamber all of them at approximate depth 2 m. Combined 3D visualization of P-wave velocity and resistivity further reinforce these interpretations, validating the efficacy of integrated geophysical surveys in non-invasively mapping buried archeological features at Saqqara. The study emphasizes the importance of combining multiple geophysical methods for archeological exploration, providing a robust framework for future investigations at the study area and other historically significant sites. Moreover, the research supports ongoing preservation efforts, highlighting the role of advanced geophysical techniques in uncovering the hidden legacies of ancient civilizations while ensuring the protection of these cultural treasures.

Lembah Bujang is well-known for its cultural heritage, comprising a vast variety of archaeological structures and artifacts that could potentially offer valuable insights into the area’s historical timeline. However, identifying buried archaeological features via geophysical surveys is a complicated process that necessitates a comprehensive comprehension of both physical properties and archaeological knowledge. To overcome this challenge, a research project was conducted to detect clay brick structures using an integration of geophysical methods such as magnetic and 2-D resistivity at two separate locations within the SB2ZZ and SB2 sites. The research discovered two primary types of archaeological features for these areas, which are mound surfaces and scattered exposed clay bricks. The magnetic data was processed to identify potential clay bricks, which were then confirmed using 2-D resistivity. At the SB2ZZ site, excavations uncovered buried clay brick structures, which reinforced the interpretation of geophysical findings. Both SB2ZZ and SB2 sites demonstrated that clay bricks typically exhibit high magnetic anomalies and resistivity values ranging from 50-140 nT and 400-1000 Ωm, respectively. In conclusion, the combined use of geophysical methods in this study provided detailed subsurface images that were validated by excavation data.

ABSTRACTThe integrated use of remote sensing (RS) techniques, vertical magnetic gradient (VMG) and electrical resistivity tomography (ERT) measurements, and, in particular, combined analysis of 2D and 3D data, can provide a viable option for the identification of targets of interest at complicated archaeological sites. In this regard, a case study is Kom C at the archaeological site of Buto (Tell El Fara'in) in the northern Nile Delta (Egypt), where satellite data (Google Earth, Landsat 8 and OrbView‐3), VMG and ERT measurements were collected prior to site excavation. In this particular case, soil salinity in the buried structures, a lack of contrast in magnetic susceptibility and electrical resistivity, as well as the orientation, complex spatial distribution and overlapping of the architectural elements, all contributed to a number of anomalies that were difficult to interpret using only 2D results. Initially, the archaeological remains were identified as being made of mud‐brick based on land surface temperature (LST) estimated from thermal bands (Bands 10 and 11) in Landsat 8. Then, the high‐resolution satellite data, as well as the VMG and ERT (2D, quasi‐3D and full 3D resistivity models), were integrated to produce a comprehensive map of buried archaeological features. Excavations by Kafrelsheikh University in collaboration with the Ministry of Tourism and Antiquities recovered archaeological remains, including architectural elements that were perhaps used for official or administrative purposes or pottery‐making workshops during the Late Roman period (between the 4th and 7th century ce). The direct comparison of geophysical results to archaeological evidence from the excavation enabled a robust interpretation of geophysical anomalies visible in the horizontal resistivity depth slice and magnetic maps. As a whole, this case study highlights the value of combining satellite data with the analysis of 2D data and 3D views of geophysical surveys to better understand the real distribution of buried archaeological remains at similar complex sites.

ABSTRACTTumuli, ancient burial mounds, stand as intriguing archaeological features, offering valuable insights into past cultures and burial practices. This paper explores the significance of tumuli inspection and utilizes electrical resistivity tomography (ERT) as a noninvasive and powerful tool for inspecting these enigmatic structures, using a nonconventional array. Tumuli, spanning various shapes and sizes, serve as repositories of cultural and funerary traditions, and understanding their internal composition is crucial for unravelling historical narratives. ERT has emerged as a promising geophysical method for investigating subsurface structures, including tumuli. By imaging the electrical resistivity of the ground, ERT enables archaeologists to map variations in soil composition and identify buried features without excavation. This paper reviews the principles of ERT and its application in tumulus studies, showcasing a case study where ERT has successfully revealed internal structures, burial chambers and associated artefacts. The use of 2D ERT is common in tumuli inspection, ignoring accurate 3D effects from the topography. Here we highlight the benefits of the 3D inversion, while we provide a different way to measure which is cost efficient and provides increased spatial resolution to the area of interest. The integration of 3D ERT into archaeological investigations not only enhances our understanding of tumuli construction but also preserves these cultural heritage sites by minimizing the need for invasive excavation. This research contributes to the evolving methodologies in archaeology, emphasizing the synergy between modern technology and traditional archaeological inquiry to uncover the secrets held within tumuli.

For over 50 years, improving the functionality per unit area has been the driving force of the semiconductor industry. Since the advent of fin field effect transistors (FETs), however, this has come at the expense of an increasingly complex device architecture. This is particularly true today as the industry is transitioning from finFETs to nanosheet (NSH) FETs. The integration of the latter devices indeed introduces the use e.g. of a modified substrate with an epitaxial SiGe/Si superlattice, of lateral etching and of size-constrained and buried gate stacks. Novel metrology concepts are therefore required to control all these new processing steps.This presentation will start by reviewing the metrology challenges encountered along the different steps of the gate-all-around (GAA) logic roadmap, from NSH to Complementary FET (CFET) [1-3]. As will be shown, the sought information moves from the surface to increasingly deeper regions of the device. This is leading to the need for so-called 3D metrology techniques focusing on buried features [4]. We will then dive into the 3D metrology solution space and demonstrate the concrete use of some of these techniques for GAA logic metrology. We conclude that, although many capabilities remain to be demonstrated, the solution space is vast such that GAA logic metrology is not expected to suffer from a capability gap. However, we foresee a heavier resort to slower solutions, which is likely to lead to a throughput or capacity gap. Luc van den Hove, The endless progression of Moore's law, Proceeding of SPIE Advanced Lithography + Patterning, PC1205301 (2022) Liao, Complementary Field-Effect Transistor (CFET) Demonstration at 48nm Gate Pitch for Future Logic Technology Scaling, IEDM 2023 M. Radosavljević et al., Demonstration of a Stacked CMOS Inverter at 60nm Gate Pitch with Power Via and Direct Backside Device Contacts, IEDM 2023J. Bogdanowicz et al., Semiconductor metrology for the 3D era, Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 1249617

We report a characterization of the spatial resolution of terahertz (THz) apertureless near-field imaging of metal lines deeply buried beneath a silicon dioxide layer. We find a good resolution for edge contrast, even in the case where the capping layer is considerably thicker than the tip radius. We find that contrast and resolution depend on demodulation frequency, thickness of the capping layer, and radius of the tip. Furthermore, we observe a distinct dependence of the contrast on the direction of the incoming radiation, in both experiments and simulations. Characterization of buried features can be a valuable tool in non-contact failure analysis of semiconductor devices.

The United Arab Emirates holds great historical importance, as evidenced by many archaeological sites, such as the Jebel Hafit Tombs and the Hili Archeological Park in Al Ain. At the western edge of Mutaredh Oasis, a major new archaeological site was discovered in 2023 during a construction project. Several important archeological features have been documented, including an earthen mosque and boundary walls, Iron Age irrigation systems, and a circular stone tomb dating to the Bronze Age. However, the eastern edge of the Mutaredh site has remained unexplored to date. Ground Penetrating Radar (GPR) has been proven to be a successful method in mapping archaeological remains. Accordingly, a high-resolution GPR survey was carried out to identify the continuity of the unearthed archeological elements and delineate new unexplored features. A comprehensive 3D model of buried archaeological features was constructed using the acquired high-resolution GPR data in the eastern part of the Mutaredh site. Several selected anomalies have been observed, similar to the uncovered features in the western part of the Mutaredh site and structures documented in other nearby archaeological sites. The geometry and extension of these anomalies have enabled the possible identification of a further two Bronze Age circular tombs, as well as the delineation of a system of water channels (falaj), and irrigation networks with tree pits from the Iron Age. Moreover, walls probably belonging to the Late Islamic Age are identified. These findings suggest that Mutaredh has been a site of intensive human activity from the Bronze Age through to the Late Islamic period. Given the density of identified anomalies, further significant features are anticipated to lie buried in the immediate surrounding areas, promising continued insights into the area’s rich archaeological heritage. The findings of this study may guide archaeologists to specific locations and assist in selecting the most appropriate excavation techniques for the verification stage.

Abstract In this study, a combined workflow of computational methodologies is introduced to explore the transformative landscape of the ancient city of Savatra (Central Anatolia Region, Türkiye), which faces long‐term risks stemming from natural and anthropogenic threats. Emphasis was placed on regional and local scale landscape analysis, employing aerial and ground‐based remote‐sensing techniques to unravel past settlement patterns and understand the impact of environmental factors, topography and natural resources on both the location of Savatra and spatial organization of its features. On a regional scale, the influence of hydrological conditions, slope and aspect on the landscape was determined through the employment of Geographical Information System (GIS)‐based analysis of digital elevation models (DEMs). At a more local scale, the utilization of the Unmanned Aerial Systems‐derived DEM and geophysical survey helped identify potential archaeological features and also assessed the risk posed to these features. Furthermore, the incorporation of 3D GIS analysis, integrating 3D point cloud representations of the ground‐penetrating radar volume and DEM, provided essential insight into the state of preservation of the buried features. The collaborative application and joint interpretation of these methodologies yielded a wide range of clues and explanations, unravelling the complex palimpsest of past activities. This research not only serves as foundation for future studies specifically for Savatra, but also provides a preliminary remote sensing–based exploration blueprint to other yet to be studied archaeological sites.

The Lower and Middle Benue Trough is an intra-continental rifted basin with most rocks concealed by thick sediments and vegetation. Geological field mapping is very difficult resulting in high uncertainties. Remote sensing and geophysical techniques can assist in refining lithological boundaries and detecting buried geological features such as intrusive bodies, which can be very useful in interpreting the structural history of a basin. The main aim of our study is to re-process and interpret aeromagnetic and multispectral satellite datasets to understand the evolution of the Benue Trough. We used high-resolution aeromagnetic data and, Landsat 8 and ASTER data sets to interpret surface and near-surface lithologies, particularly igneous bodies, within the Benue Trough, Nigeria, with the aim of better constraining the basin evolution in time and space. A matched bandpass filter was applied to the aeromagnetic data to separate shallow/near-surface (residual) anomalies from deep (regional) anomalies. The result of the residual anomaly was further filtered by derivative-based filters to delineate surface/near-surface igneous bodies. The satellite remote sensing datasets were processed and enhanced, and diagnostic mineral spectral signatures related to geology were interpreted. A spectral angle mapping (SAM) supervised classification was used to map various lithologies and their boundaries. The delineated igneous bodies (volcanic rocks, plugs, dykes, bosses, and sills) are concentrated along the SE margin of the Trough where they intruded along a major NE-SW trend; but changes in the intrusion style are interpreted to relate to specific stages in the basin history. We suggest that the initial magma emplacement was controlled by structures mostly along the SE margin of an asymmetric basin, but the rifting locus later migrated towards the centre of the present basin.

Piezoresponse force microscopy (PFM) is one of the most widespread methods for investigating and visualizing ferroelectric domain structures down to the nanometer length scale. PFM makes use of the direct coupling of the piezoelectric response to the crystal lattice, and hence, it is most often applied to spatially map the three-dimensional (3D) near-surface domain distribution of any polar or ferroic sample. Nonetheless, since most samples investigated by PFM are at least semiconducting or fully insulating, the electric ac field emerging from the conductive scanning force microscopy (SFM) tip penetrates the sample and, hence, may also couple to polar features that are deeply buried into the bulk of the sample under investigation. Thus, in the work presented here, we experimentally and theoretically explore the contrast and depth resolution capabilities of PFM, by analyzing the dependence of several key parameters. These key parameters include the depth of the buried feature, i.e., here a domain wall (DW), as well as PFM-relevant technical parameters such as the tip radius, the PFM drive voltage and frequency, and the signal-to-noise ratio. The theoretical predictions are experimentally verified using x-cut periodically poled lithium niobate single crystals that are specially prepared into wedge-shaped samples, in order to allow the buried feature, here the DW, to be “positioned” at any depth into the bulk. This inspection essentially contributes to the fundamental understanding in PFM contrast analysis and to the reconstruction of 3D domain structures down to a 1 μm-penetration depth into the sample.

Holocene records of oyster reefs in a shallow semi-enclosed island embayment of the Aegean Sea

Abstract Debris‐covered glaciers (DCG) and rock glaciers have been increasingly studied in recent years because of the role they play within local watersheds, glacial ablation models due to climate change, and as analogs for buried ice features on planetary bodies such as Mars. Characterizing the supraglacial debris layer is a large part of these efforts. Geophysical exploration of DCG has mostly excluded active seismic methods, with the exception of refraction studies, due to the attenuating properties of the debris cover and field survey efficiency. We evaluate the accuracy, field efficiency, and effectiveness of seismic refraction, reflection, and surface‐wave surveys for determining the elastic properties of the debris layer and any underlying layers on DCG using the Sourdough Rock Glacier in Southcentral Alaska as a test site. We provide evidence for imaging an ultra‐shallow seismic reflection from the bottom of the loose debris layer using ultra‐dense receiver arrays and compare it to ground‐penetrating radar (GPR) images taken along the same profiles. We also detail how reliable dispersion curve images can be extracted from the surface wave package of the seismic data using the multi‐channel analysis of surface waves technique, which allows for the (s)‐wave profile to be inverted for. We find this could be a valuable addition to the toolbox of future geophysical investigations on DCG.

The power conversion efficiency of inverted perovskite solar cells (PSCs) based on p–i–n structure exceeds 25%, largely owning to the persistent improvement on the quality of heterojunction interface. Nickel oxide (NiOx) of low cost and superior chemical stability is one of the most promising candidates as hole‐transport material that is suitable for large‐scale fabrication. Meanwhile, the certified efficiency of inorganic NiOx‐based inverted PSCs surpasses 25% via improving the poor quality of buried interface contact, which is originated from large offset of valence band energy level, as well as high density of interfacial defects between NiOx hole‐transport layer and perovskite film. In this review, the development and progress in buried interface engineering of inorganic NiOx layer are systematically summarized, including strategies on energy level alignment and interfacial defect passivation, which are adopted to promote the better energy level alignment and suppress the defect‐assisted nonradiative recombination at interface. On the basis of deeper understanding of buried interface features, some novel materials and methods for interface modification can be rationally designed. Perspectives on future development of efficient and stable large‐scale perovskite solar modules and tandem cells are also provided.

Ground penetrating radar investigations of buried remnants at ancient capital cities of Panchala and Vatsa kingdoms spread along Ganga-Yamuna doab of India from 600 BCE to 1100 CE

Sparse filtering (SF) has received considerable attentions in the machinery fault diagnosis thanks to its ability to extract the fault-related features using their sparsity. However, the existing SF methods have dilemmas with the empirical selection of model parameters, the loss of fault-related information caused by a screening way for the target mode, and the singularity of results induced by some large-amplitude random impulses (LARIs). Hence, a manifold learning-assisted SF method is proposed for machinery fault-related feature enhancement in this study. First, an improved intrinsic component filtering (ICF) is presented for extracting the multiple modes with feature enhancement, where the parameters of ICF are adaptively determined by using the optimization object to avoid the empirical selection of parameters. Second, the manifold learning is introduced to compress the enhanced multiple modes to overcome the loss of fault-related information; thus the intrinsic manifolds are obtained for disclosing the buried fault-related features and suppressing the band-in noise. Third, an adaptively weighting strategy for these intrinsic manifolds is constructed to obtain a final representative mode for conducting the machinery fault diagnosis. Meanwhile, the LARIs coupled with intrinsic manifolds are calibrated according to their statistical information to resolve the singularity of the representative features. Simulation and experiments show that the proposed method is more effective in extracting fault-related features than some existing methods.