Journal of Applied Geophysics最新文献

Seepage hazards in dams remain a critical issue in flood control engineering. The pseudo-flow field method has shown high efficacy in detecting seepage points within dam structures. This paper delves into the core characteristics of the pseudo-flow field method, aiming to accelerate its detection speed in practical engineering contexts. By employing the Laplace equation for electric current, we established a numerical model to simulate the method's application in real-world scenarios. The simulation reveals the key characteristics of potential and current density distributions along measuring lines within the pseudo-flow field. Both horizontal and vertical measuring lines show a peak distribution of current density and potential near the seepage point, gradually diminishing towards the periphery. Conversely, vertical measuring lines further from the seepage point exhibit minimal changes, presenting a uniform distribution of current density and potential. The results confirm that the pseudo-flow field method can effectively detect seepage locations and that strategic placement of measuring lines can markedly improve detection speed.

The gravity and magnetic anomalies in the Qihe-Yucheng mineral-rich area of Shandong Province, China, lie nearly north–south. However, the anomalies in the Pandian area in the central part of the region are small in scale and weak in intensity, and the geophysical information of deep iron ore bodies is greatly weakened, making it difficult to identify and extract mineral-induced magnetic anomalies. Based on the exploration of gravity and magnetic anomalies in adjacent mining areas, and through plane analysis and quantitative inversion of these anomalies in the Pandian area, the structural framework division, delineation of ore-forming geological bodies, anomaly analysis research, and two-and-a-half dimensional (2.5D) joint inversion in the study area were achieved. Deep information under an ultradeep overburden was obtained, and a new breakthrough in the exploration of skarn-type iron ore was achieved. The results of this study can provide important references for further exploration of deep ore deposits under ultra-deep overburden layers and indicate the potential for the exploration of skarn-type iron deposits in the Qihe-Yucheng mineral-rich area.

Submarine mud diapirs (MDs) and volcanoes, often linked with gas hydrates and hydrocarbons, are prevalent features in the offshore region of SW Taiwan. Despite their significance, the gravity signatures of these MDs have not been investigated except for a few studies. Therefore, our study aims to address this gap by employing a recently proposed optimization algorithm, Hunger Games Search (HGS), to estimate model parameters of an inclined 2D anticlinal structure representative of an active MD. This approach was implemented to gravity anomaly obtained from SW coast of Taiwan. Before its application, we explored the nonlinear and high-dimensional characteristics of the cost function associated with this inverse problem by generating error landscape maps for model parameter pairs. Subsequently, to mitigate the challenges, a parameter tuning procedure was performed. Using the optimal control parameters derived from this procedure, we increased the efficacy of the HGS algorithm for the problem handled. Furthermore, we employed standard Particle Swarm Optimization (PSO), a widely utilized metaheuristic in geophysical inversion studies, for a comparison. The findings showed that the proposed novel algorithm yielded superior accuracy and reliability compared to PSO. Additionally, the inclined anticlinal structure exhibited better agreement with interpretation obtained from available seismic reflection outcomes, in contrast to approximation based on inclined dike-like structure. Besides, comparative analyses between HGS and two well-established techniques, namely correlation imaging and compact inversion algorithms further validated the effectiveness of HGS. Consequently, we assert that the novel HGS optimizer is a robust and appealing tool for inverse gravity problems. Moreover, assuming a 2D inclined anticlinal source type holds promise for extended investigations into other MDs in SW Taiwan's upper slope region. Such efforts can significantly enhance the understanding of regional mud diapirism and volcanism on a broader scale.

The pressure stimulated current (PSC) signal emitted during the deformation and fracture processes of coal and rock materials holds significant importance for monitoring dynamic disasters in coal mines. However, the spatial response characteristics remain inadequately explored, posing significant challenges to the identification of risk-prone areas for underground dynamic disasters. To study the temporal and spatial response characteristics of PSC signal, the PSC response experiment in the failure process of raw coal under load was carried out, PSC signals from various spatial positions of coal were collected throughout the loading process. The results show that the sudden increase of axial PSC and the sudden decrease of transverse PSC appear with the sudden increase of acoustic emission (AE) hit rates, which is the main characteristic of the aggravation of coal internal fracture degree. The PSCs are closely related to the damage characteristics of the sample in terms of its corresponding position and drop time, which can better reflect the fracture concentration location of the coal sample. Building upon this foundation, the paper explained the internal factors contributing to variations in PSC spatial response characteristics of coal samples during load failure and emphasizes the inhibitory effect of crack development on PSC changes.

Recent studies demonstrate the effectiveness of integrated archaeo-geophysical tools in resolving various geological-environmental challenges. This involves combining geophysical methods in archaeological fieldwork or remote sensing methods for preliminary survey and analysis of archaeological sites, potentially enhanced by machine learning techniques to estimate object shapes and characteristics. This study highlights the potential of employing informational and probabilistic approaches as optimal tools for evaluating and integrating critical information for archaeological research. Our proposed procedure for assessing the reliability of tools or toolsets is based on improved methodologies utilizing conditional probability, which were suggested in previous authors' publications. We illustrate examples of combining remote sensing, known for its low cost, portability, and effectiveness in initial archaeological site identification, with machine learning methods to locate and discover new sites in archaeologically well-studied areas in Israel. Subsequently, we conduct an informational assessment of remote sensing data and propose steps to correlate this data with other geophysical information probabilistically.

Parowan Valley, Utah is an agricultural area experiencing significant subsidence in recent decades due to extensive groundwater extraction. The subsidence occurs primarily due to consolidation in fine-grained units as groundwater heads decrease due to pumping. Efforts to predict future subsidence would be facilitated by an accurate understanding of the distribution of fine-grained materials in the subsurface. An analysis of drillers' logs across Parowan Valley from previous research indicates that significant fine-grained units are present, but the variable quality of these logs, as well as the limited spatial distribution of borings, makes the accurate determination of the location and extent of fine-grained units challenging. To overcome the limitations of drillers' logs analysis, ground-based and borehole geophysical data were acquired. The ground-based data were collected over large sections of the valley using a towed Time-Domain Electromagnetic (tTEM) system that measures electrical resistivity over different depth intervals. These data were used to characterize the distribution of fine- and coarse-grained sediments within the tTEM depth of investigation of ∼60 m. Borehole gamma data were acquired in three boreholes near the tTEM traverses to compare with resistivity data and drillers' logs for further validation of tTEM resistivity data. In this study, we developed a methodology for rock physics transforms in regions with sparse geological information and variable saturation, as well as a scheme for using a variety of methods depending on the availability of lithology information, enabling us to produce robust rock physics transforms in an area with complex geological conditions.

The Roman Villa at Piazza Armerina, which has been on the UNESCO list of sites since 1997, is an exceptional example of a prestigious residence from the Late Antiquity period.

Most of the area around the villa has not yet been explored and it is thought there are structures linked to the layout of the villa itself and subsequent modifications from the medieval era.

With these assumptions and to plan an excavations campaign in the area close to the villa's warehouses geophysical surveys were undertaken in the summer of 2022 and 2023.

Ground penetrating radar, magnetometry (in gradiometric configuration), and inductive electromagnetometry geophysical methods were used. These different methods were taken into consideration depending on the more or less conductive subsoil matrix. Results show the presence of several structures of archaeological interest.

Here, we investigate transport behaviour through two types of media, silica sand and zeolite, using tracer column experiments and numerical methods. Tracer experiments with sodium chloride (NaCl) were conducted in saturated packed columns with embedded current and potential electrodes to measure co-located bulk electrical conductivity (${\sigma }_b$) and fluid electrical conductivity (${\sigma }_f$) to characterise dual-domain mass transfer (DDMT). Unexpectedly, the silica sand experiments show a hysteretic relationship between co-located ${\sigma }_f$ and ${\sigma }_b$. Field Emission Scanning Electron Microscopy (FESEM) analysis results showed that the observed hysteresis could be due to the presence of aggregated particles. NaCl tracer experiments in the zeolite column confirmed that the intragranular porosity serves as an immobile domain to store solute, resulting in heavy-tailed breakthrough curves (BTCs) and hysteresis between co-located ${\sigma }_b$ and ${\sigma }_f$. The root mean square error (RMSE) between the experimental and simulated ${\sigma }_f$ revealed that the single-rate dual-domain mass transfer (DDMT) model captures the NaCl BTCs much better than the advection-dispersion equation (ADE). Based on a Monte Carlo analysis, the obtained single-rate DDMT parameters were velocity-dependent in such a way that the estimated first-order mass transfer rate coefficient ($\alpha$) increased with an increase in flow rate. The findings of this research confirm the superiority of the non-Fickian theory over the classical model in understanding solute transport in natural porous media. The results also illustrate that in addition to the physical and chemical characteristics of the soil, which leads to the non-Fickian transport, the flow velocity plays an important role in physical solute transport parameters.

A multi-method geophysical investigation was carried out in the context of a recovery project for the “Annunziata” Garden located in the town of Cammarata (Sicily), near to the homonymous church (Chiesa dell'Annunziata). In this area, according to the scarce historical sources, there was a Benedictine convent, probably demolished in the 18th century, but the area was probably inhabited even in earlier periods. Preliminarily, a series of 2D electrical resistivity tomographies (2D-ERT) were carried out approximately parallel to each other, some of which highlighted resistivity anomalies that could be attributed to buried archaeological structures. Consequently, in a smaller area where these anomalies were evident, a 3D electrical resistivity tomography (3D-ERT) and Ground Penetrating Radar (GPR) parallel profiles were carried out aimed at a detailed 3D reconstruction of the subsoil. Despite the unclear correspondence between the 3D-ERT inverse model and the GPR one, the 3D ERT confirmed the anomalies found with the previous 2D-ERT surveys, better defining its contours and geometries. The geophysical reconstructions served to indicate to the archaeologists the most promising areas for excavation tests that were carried out subsequently and confirmed the presence of archaeological structures, such as defensive walls whose origin and dating are still the subject of further archaeological studies.

This paper presents the integration of advanced 3D digitization and visualization technologies in the study and preservation of prehistoric megalithic heritage sites in the Mediterranean. We focus on the digital documentation and analysis of the Borġ in-Nadur megalithic complex and other notable sites, employing a combination of terrestrial laser scanning, aerial and terrestrial digital photogrammetry. The research highlights how digital tools not only enhance the precision of archaeological documentation but also promote virtual accessibility and offer new insights into the archeoastronomical significance of these structures. We discuss the production of high-resolution digital replicas, their utility in virtual reconstructions, and the role of digital platforms in public engagement and scholarly study. The findings underscore the potential of digital technologies to revolutionize heritage conservation and research, providing a comprehensive digital approach to the safeguarding and understanding of our ancient heritage.