Subsurface Channels Research Articles

Microgravity Survey to Evaluate Earthquake Effects on the Derbendikhan Dam Site, Iraq

ABSTRACT A microgravity investigation was conducted along the axis of the Derbendikhan rockfill dam in Iraq. The dam lies in an earthquake-prone area within the High Folded Zone of the Western Zagros Fold–Thrust Belt. The goal of the survey was to evaluate the expected subsurface damage that could threaten the stability of the dam due to the effects of a 7.3 magnitude earthquake and future earthquakes that cause foundation cracking and landslides. The survey consists of 324 microgravity stations distributed on four profiles. Residual gravity anomalies were obtained by removing the regional effect of a 5-m upward continuation filter. Several negative and positive anomalies are distinguishable in a residual anomalies map that reflects the subsurface heterogeneity within the clay material that makes up the dam. The results reveal that there are no recognizable indications regarding the evolution of subsurface channels after the earthquake was given. Furthermore, two prominent anomalies appear close to the right bank at roughly 21 m in depth. These positive and negative anomalies suggest that high- and low-density zones coincide with different degrees of compressional stresses caused by the earthquake. Two-dimensional modeling indicates several low (less compacted) and high (more compacted) density areas that warrant further investigation in terms of material strength. The results can be used as a guide for a drilling program to examine the sources of the anomalies.

Subsurface acoustic ducts in the Northern California current system.

This study investigates the subsurface sound channel or acoustic duct that appears seasonally along the U.S. Pacific Northwest coast below the surface mixed layer. The duct has a significant impact on sound propagation at mid-frequencies by trapping sound energy and reducing transmission loss within the channel. A survey of the sound-speed profiles obtained from archived mooring and glider observations reveals that the duct is more prevalent in summer to fall than in winter to spring and offshore of the shelf break than over the shelf. The occurrence of the subsurface duct is typically associated with the presence of a strong halocline and a reduced thermocline or temperature inversion. Furthermore, the duct observed over the shelf slope corresponds to a vertically sheared along-slope velocity profile, characterized by equatorward near-surface flow overlaying poleward subsurface flow. Two potential duct formation mechanisms are examined in this study, which are seasonal surface heat exchange and baroclinic advection of distinct water masses. The former mechanism regulates the formation of a downward-refracting sound-speed gradient that caps the duct near the sea surface, while the latter contributes to the formation of an upward-refracting sound-speed gradient that defines the duct's lower boundary.

Crack propagation in adhesive bonded 3D printed polyamide: Surface versus bulk patterning of the adherends

The confined build space of 3D printers often necessitates breaking down larger objects into sub-components for efficient printing. Addressing this challenge, related existing research emphasizes the growing adoption of structural adhesives as a key method for joining 3D printed components. In this context, the present study combines finite element modeling, design exploration, and additive manufacturing, to ascertain the role of the adherends’ architecture on the mechanics of crack growth in adhesive bonded 3D printed materials. Finite element simulations and experiments are carried out using Double Cantilever Beam (DCB) specimens comprising epoxy-bonded selective laser sintered polyamide (PA). In particular, the study includes adherends that feature either sub-surface hollow channels of various shapes (bulk patterns) or sinusoidal interfaces with different aspect ratios (surface patterns). The objective is to demonstrate how the proposed patterning strategies not only promote crack shielding and delayed growth but also unlock energy-absorbing processes, such as interfacial void growth and buckling, that are absent in the control joint (i.e., no patterns). Therefore, customizing the architecture of the adjoined layers ultimately results in toughening and enhanced damage tolerance in adhesive joints that comprise 3D printed materials.

Temporal Stability of Grassland Soil Moisture Utilising Sentinel-2 Satellites and Sparse Ground-Based Sensor Networks

Soil moisture is important for understanding climate, water resources, water storage, and land use management. This study used Sentinel-2 (S-2) satellite optical data to retrieve surface soil moisture at a 10 m scale on grassland sites with low hydraulic conductivity soil in a climate dominated by heavy rainfall. Soil moisture was estimated after modifying the Optical Trapezoidal Model to account for mixed land cover in such conditions. The method uses data from a short-wave infra-red band, which is sensitive to soil moisture, and four vegetation indices from optical bands, which are sensitive to overlying vegetation. Scatter plots of these data from multiple, infrequent satellite passes are used to define the range of surface moisture conditions. The saturated and dry edges are clearly non-linear, regardless of the choice of vegetation index. Land cover masks are used to generate scatter plots from data only over grassland sites. The Enhanced Vegetation Index demonstrated advantages over other vegetation indices for surface moisture estimation over the entire range of grassland conditions. In poorly drained soils, the time lag between satellite surface moisture retrievals and in situ sensor soil moisture at depth must be part of the validation process. This was achieved by combining an approximate solution to the Richards’ Equation, along with measurements of saturated and residual moisture from soil samples, to optimise the correlations between measurements from satellites and sensors at a 15 cm depth. Time lags of 2–4 days resulted in a reduction of the root mean square errors between volumetric soil moisture predicted from S-2 data and that measured by in situ sensors, from ~0.1 m3/m3 to <0.06 m3/m3. The surface moisture results for two grassland sites were analysed using statistical concepts based upon the temporal stability of soil water content, an ideal framework for the intermittent Sentinel-2 data in conditions of persistent cloud cover. The analysis could discriminate between different natural drainages and surface soil textures in grassland areas and could identify sub-surface artificial drainage channels. The techniques are transferable for land-use and agricultural management in diverse environmental conditions without the need for extensive and expensive in situ sensor networks.

Deciphering Martian Flood Infiltration Processes at Hebrus Valles: Insights From Laboratory Experiments and Remote Sensing Observations

AbstractIn evaluating the unique geomorphology of Hebrus Valles on Mars, an outflow channel southeast of Utopia Planitia, we investigated the role of fluvial dynamics in forming subsurface conduits. Unlike typical Martian channels that terminate under younger sediment rocks, Hebrus Valles retains its downstream features, thus offering a window into surface and subsurface interactions between liquid water and regolith. Employing physical lab simulations, we utilized buried polygonal tunneling configurations in a sandy matrix to replicate the incision features observed at the channel's terminus. This study provides the first lab‐based evidence demonstrating the role of conduits in conveying large floods in the Hebrus Valles. Our results lend support to the interpretation that Hebrus Valles conveyed high‐volume floods by demonstrating that conduits are necessary to form the features observed on the surface of Hebrus Valles. The experiments also highlight the role of sinkholes as floodwater capture points, which suggests the formation of a regional interconnected network of subsurface channels and caverns. These findings affirm that fluvial dynamics in Hebrus Valles could have expanded subsurface discontinuities into functioning conduit systems, potentially directing floodwaters through an interconnected subterranean network.

Imaging Subsurface Channels within the Tertiary Niger Delta Basin using Spectral Decomposition Methods

Abstract Channels are hydrocarbon prospective areas which are often below the resolution of seismic data. This study was therefore conducted with the aim of using spectral decomposition methods for imaging of buried channels and associated structures in a 3D Post-Stack Depth Migrated (PSDM) volume acquired from a field in the Niger Delta Basin. Two commonly used spectral decomposition methods were used to enhance the resolution of seismic data for interpretation. The methods utilized included Fast Fourier Transform (FFT) and Continuous Wavelet Transform (CWT). Petrel and Opendtect were the interpretational software tools utilized for the study. The seismic data was conditioned using structural smoothing, and a zone of interest was selected around -1000 to -3000ms. Three dominant frequencies were selected from the sub-volume generated around the zone of interest. The frequencies were 10Hz, 25Hz and 32Hz respectively. These frequencies were extracted from the seismic data using FFT and CWT decomposition methods. The results were colored using Red, Green and Blue (Red for 10Hz, Green for 25Hz and Blue for 32Hz). These frequencies were then blended together in a process called RGB blending. The resultant output was a mix of only these three dominant frequencies. Analysis of these results revealed the presence of several channels, crevasse splay deposits, flood-plains and faults on two time-slices obtained at -2020ms and -1800ms. The channels were meandering channels of low sinuosity, some of which were fault controlled. The crevasse splay deposits were significantly large and increased in number at the shallow time-slice. Some of the crevasse splay deposits were found bifurcating fault lines and being deposited on floodplains, indicating that they were younger than the faults. Channel flow direction was from East to West, while channel migration was from South to North of the study area. The increase in the number of channels from the base to the top of the seismic data suggested a multistory stacked channel system. It was established that channels and crevasse splays were best enhanced using the FFT decomposition method while major and minor faults were best enhanced using CWT method. Hence, this study has proven that the spectral decomposition method is very effective in imaging subsurface buried channels, thus delineating prospects and can be used for reservoir characterization. Keywords: Spectral decomposition, Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Channels, Crevasse splays, Faults, Reservoir Characterization.

Improving the stability of the friction stir channelling technology via a cooled copper backing plate

The development of the friction stir channelling (FSC) technology has a potential to revolutionize the manufacturing industry, providing an innovative way to produce continuous sub-surface channels in monolithic components in a single step. However, the process generates heat that can lead to defects and loss of stationarity, affecting the quality of the channels produced and the process’ efficiency and control. To address these challenges, a ground-breaking study was conducted using a cooled copper backing plate to adjust the process temperatures and investigate the influence of the temperature on FSC stability. The results of the study showed that the cooled copper backing plate has a significantly higher rate of heat conduction, effectively preventing the processed component from overheating and ensuring that the process maintains its stationarity. When using the steel backing plate, only one combination of process parameters (a rotation speed of 450 rev/min and a traverse speed of 71 mm/min) yielded satisfactory results. Moreover, the use of the cooled copper backing plate allowed for a wider range of process parameters to be employed, resulting in sub-surface channels with higher quality and fewer defects. The 710/71 parameters combination resulted in a lower heat input, while the 900/45 parameters set produced channels with a more rectangular geometry. A rotation speed of 900 rev/min and a traverse speed of 45 mm/min have been shown to be the best choice. This innovative approach to FSC technology represents a major step forward in solid-state manufacturing, envisaging new possibilities for producing longer sub-surface channels with superior quality and greater efficiency.Highlights• Conducting the FSC process at low temperature has improved its stability.• The use of a cooled copper backing plate enabled a broader range of FSC process parameters.• Longer and stabler leak-free sub-surface channels have been produced in aluminium alloys.Graphical

Characteristics of karst caves inferred from microtremor studies: A case study from Cerme Cave, Yogyakarta, Indonesia

A microtremor survey based on ground surface data acquisition was used to identify and characterize the karst area of Cerme Cave, Yogyakarta, Indonesia, from the entrance to the exit of the cave. The entrance and exit of the cave are used as tie-in points because the characteristics of the two locations can be directly observed. Parameters used in this study include ground vibration amplification, shear wave velocity, and Poisson’s ratio. The presence of cavities can be characterized by a relatively strong contrast between these physical parameters and their surroundings. The exit of the cave, which can be considered as a sinkhole, has a dominant frequency of 3.2 to 4.6 Hz, which is relatively higher than that of the surrounding area. At the entrance of Cerme Cave, which has a large cavity, a small ground vibration amplification was detected, less than 0.1. The entrance and exit of the cave also exhibit a low shear wave propagation velocity of less than 350 m/s. The presence of a subsurface fluvial channel in Cerme Cave can be characterized by a high Poisson’s ratio of 0.4–0.5, a gain value of less than 0.1, and a shear wave velocity of less than 350 m/s.

Subsurface sound channel and seasonal variation of its characteristics in the mid-latitude of Northwest Pacific

Subsurface sound channel and seasonal variation of its characteristics in the mid-latitude of Northwest Pacific

Revealing subsurface subtle channel boundaries and fluid discrimination by employing time-frequency analysis on pre-stack seismic data, a case study: Simian Field, Offshore Nile Delta, Egypt

It is quite difficult to determine the interior depositional architecture and fluid signature of slope channel systems in offshore deltas by using conventional seismic data as occasionally the subsurface channels might not give a clear response to the seismic images. Utilizing the spectrum decomposition approach, the Pre-stack seismic data is highly beneficial for depositional and hydrocarbon highlights. Far-angle stacks are also better for fluid identification than near-angle stacks because they have more low-frequency components and a lower signal-to-noise ratio (SNR) than near-angle stacks, which are more marked by a depositional signature.In the present study, the spectral decomposition approach, which concentrates on processing Discrete Fourier Transform (DFT) around a specified structural map, is implemented to transpose the amplitude or phase data into the frequency domain. Red-Green-Blue (RGB) blending map was extracted from the near and far-stack seismic data, through which the channel depositional geometries become clear. However, utilizing RGB on the far stack made the fluid signature fairly obvious.

Observations of the space/time scales of Beaufort sea acoustic duct variability and their impact on transmission loss via the mode interaction parameter.

The Beaufort duct (BD) is a subsurface sound channel in the western Arctic Ocean formed by cold Pacific Winter Water (PWW) sandwiched between warmer Pacific Summer Water (PSW) and Atlantic Water (AW). Sound waves can be trapped in this duct and travel long distances without experiencing lossy surface/ice interactions. This study analyzes BD vertical and temporal variability using moored oceanographic measurements from two yearlong acoustic transmission experiments (2016-2017 and 2019-2020). The focus is on BD normal mode propagation through observed ocean features, such as eddies and spicy intrusions, where direct numerical simulations and the mode interaction parameter (MIP) are used to quantify ducted mode coupling strength. The observations show strong PSW sound speed variability, weak variability in the PWW, and moderate variability in the AW, with typical time scales from days to weeks. For several hundreds Hertz propagation, the BD modes are relatively stable, except for rare episodes of strong sound speed perturbations. The MIP identifies a resonance condition such that the likelihood of coupling is greatest when there is significant sound speed variability in the horizontal wave number band 1/11<kh<1/5 km-1. MITgcm ocean model results are used to estimate sound speed fluctuations in this resonance regime.

Investigating the Relationship between the Manning Coefficients (n) of a Perforated Subsurface Stormwater Drainage Pipe and the Hydraulic Parameters

Subsurface perforated pipes drain infiltrated stormwater runoff while attenuating the peak flow. The Manning roughness coefficient (n) was identified as a fundamental parameter for estimating roughness in various subsurface channels. Hence, in this work, the performance of a six-row non-staggered sand-slot perforated pipe as a sample of the subsurface drainage is investigated experimentally in a laboratory flume at Universiti Sains Malaysia (USM) aimed at determining the Manning roughness coefficients (n) of the pipe and assessing the relationship between the Manning’s n and the hydraulic parameters of the simulated runoff flow under the conditions of the tailgate channel being opened fully (GFO) and partially (GPO), as well as the pipe having longitudinal slopes of 1:750 and 1:1000. Water is pumped into the flume at a maximum discharge rate of 35 L/s, and the velocity and depth of the flow are measured at nine points along the inner parts of the pipe. Based on the calculated Reynolds numbers ranging from 38,252 to 64,801 for both GFO and GPO conditions, it is determined that most of the flow in the perforated pipe is turbulent, and the calculated flow discharges and velocities from the outlets under GFO are higher than the flow and velocity rates under GPO with similar pipe slopes of 1:750 and 1:1000. The Manning coefficients are calculated at nine points along the pipe and range from 0.004 to 0.009. Based on the ranges of the calculated Manning’s n, an inverse linear relationships between the Manning coefficients and the flow velocity under GFO and GPO conditions are observed with the R2 of 0.975 and 0.966, as well as 0.819 and 0.992 resulting from predicting the values of flow velocities with the equations v = ((0.01440 − n)/0.009175), v = ((0.01330 − n)/0.00890), v = ((0.02007 − n)/0.01814), and v = ((0.01702 − n)/0.01456) with pipe slopes of 1:750 and 1:1000, respectively. It is concluded that since the roughness coefficient (Manning’s n) of the pipe increases, it is able to reduce the flow velocity in the pipe, resulting in a lower peak of flow and the ability to control the quantity of storm water in the subsurface urban drainages.

Seismic geomorphological analysis of channel types: a case study from the Miocene Malay Basin

Abstract Imaging the subsurface is a major challenge due to many aspects; the most notable is the resolution of the data, which often leads to misinterpretation of reservoir behaviour and depositional environment. Even with the robust tools available to precisely model the subsurface reservoir and depositional architecture, a precise result is still incorrect if derived from an inaccurate subsurface description. Recent advances in 3D seismic geomorphology analytical methods, particularly the application of root mean square (RMS) and frequency decomposition analysis, have enabled detailed imaging, description and classification of subsurface channel networks. Typically, it is easier to image shallow subsurface channels (&amp;lt;500 m depth), but it gets increasingly challenging to recognize channel features at subsurface depths ≥1.5 km. This paper presents the characterization of channel features imaged from such depths within the Miocene section of the Malay Basin, offshore Peninsular Malaysia. An integrated dataset from a selected area in the central region of the Malay Basin was used for this study, including a high-quality 3D seismic cube (1563 km2) and data from one well penetrating the Miocene section of the Malay Basin. We have identified five seismic geobody groups and 10 channel types from both planform and cross-section views. The dimensions, shapes, sinuosities and thicknesses of these channel types vary. Additionally, they display various seismic characteristics in cross-section and planform views. Variability in channel geometries is related to the complex interplay between fluvial and marine processes.

Calculation of parameters of subsurface ridges in a steady flow of groundwater channels

In solving the problems associated with the design and operation of large canals with many subsurface channels, it is important to determine the parameters of the parameters of the grids moving under the bottom and the flow rates. To date, a large number of field and laboratory research data on the movement of groups in the world have been obtained. Attempts have been made by some authors to summarize this information, but so far they have not been able to obtain perfectly reliable results. Therefore, new suggestions are being made by researchers to improve the formulas previously obtained.

Characterization of Subsurface Hydrogeological Structures With Convolutional Conditional Neural Processes on Limited Training Data

AbstractOne of the main issues in the application of statistical‐learning‐based methods to the characterization of hydrological phenomena is the complex parameterization of the high‐quality reconstruction. The difficulty of obtaining enough training data and generating multiple‐scale structures hinder the applications of deep‐learning‐based methods in hydrogeological modeling. Hydrogeological modeling problems can be regarded as stochastic processes, and we propose a novel hydrogeological modeling approach based on convolutional conditional neural processes (GM‐ConvCNPs), a meta‐learning approach for dealing with stochastic processes. In this work, GM‐ConvCNP is used to reconstruct the entire spatial structures of subsurface hydrological attributes and channels from a limited amount of conditioning data. To achieve 3‐D characterization of subsurface structures, 3‐D GM‐ConvCNP is proposed according to the spatial distribution characteristics of 3‐D conditioning data. Compared to other deep‐learning‐based methods, we use a small amount of training data and obtain positive model generalization capabilities. Four data sets of categorical and continuous hydrogeological structures are exploited in the experiments. Various validation tests including variograms, connectivity functions, and multi‐dimensional scaling (MDS) map are used to evaluate the quality of generated realizations. The proposed approach is able to significantly reduce training consumption and improve the performance of realizations compared to a set of different benchmark tests. The experiments confirm that the GM‐ConvCNP model can extract heterogeneous patterns by using meta‐learning from limited training data and reconstruct multiple‐scale hydrogeological structures. A case study demonstrates that our method can be applied to characterize multiple‐source hydrological variables.

Geology of Ayn Al Majdoub Karstic Lake, Benghazi, NE Libya

The major karstic area in Libya known as Ayn Zayanah system is a unique phenomenon of concentrated karstic surface and subsurface dolines and channels. By focusing on Al Majdoub Lake, as a case study, we can better understand how lithology, structure and hydrology contribute to the regional formation of the Karstic system. Geologically, the limestones of the middle Miocene, Benghazi Formation is forming the northern side of Benghazi region, which is characterized by well-developed surficial, interface, surface and subsurface karstic features that are open or filled with sediment. The formation of Ayn Majdoub doline is filled with saline water, which is attributed to the dissolution of a buried carbonate layer by fresh groundwater due to the drop of the Sea level and the associated groundwater levels. This is combined with epeirogenesis movements, which have caused the development of karstification to reach a depth of 130-150 m below present sea level in the Benghazi plain. Through this Karstic system, groundwater seeps from Benghazi Basin towards the Ayn Zayanah (The Spring) and then to the Blue Lagoon (The Lake) finally to the sea.

Review on the Geophysical and UAV-Based Methods Applied to Landslides

Landslides (LS) represent geomorphological processes that can induce changes over time in the physical, hydrogeological, and mechanical properties of the involved materials. For geohazard assessment, the variations of these properties might be detected by a wide range of non-intrusive techniques, which can sometimes be confusing due to their significant variation in accuracy, suitability, coverage area, logistics, timescale, cost, and integration potential; this paper reviews common geophysical methods (GM) categorized as Emitted Seismic and Ambient Noise based and proposes an integrated approach between them for improving landslide studies; this level of integration (among themselves) is an important step ahead of integrating geophysical data with remote sensing data. The aforementioned GMs help to construct a framework based on physical properties that may be linked with site characterization (e.g., a landslide and its subsurface channel geometry, recharge pathways, rock fragments, mass flow rate, etc.) and dynamics (e.g., quantification of the rheology, saturation, fracture process, toe erosion, mass flow rate, deformation marks and spatiotemporally dependent geogenic pore-water pressure feedback through a joint analysis of geophysical time series, displacement and hydrometeorological measurements from the ground, air and space). A review of the use of unmanned aerial vehicles (UAV) based photogrammetry for the investigation of landslides was also conducted to highlight the latest advancement and discuss the synergy between UAV and geophysical in four possible broader areas: (i) survey planning, (ii) LS investigation, (iii) LS dynamics and (iv) presentation of results in GIS environment. Additionally, endogenous source mechanisms lead to the appearance of deformation marks on the surface and provide ground for the integrated use of UAV and geophysical monitoring for landslide early warning systems. Further development in this area requires UAVs to adopt more multispectral and other advanced sensors where their data are integrated with the geophysical one as well as the climatic data to enable Artificial Intelligent based prediction of LS.

The Beaufort Sea acoustic duct's variability and its impact on acoustic propagation using the mode interaction parameter

The Beaufort duct is a subsurface sound channel formed by cold Pacific Winter Water sandwiched between warmer Pacific Summer Water and Atlantic Water in the Western Arctic Ocean. This duct traps sound waves and allows them to travel long distances without losing energy to lossy interactions with sea ice and surface waves. This study quantifies Beaufort duct variability based on Canada Basin Acoustic Propagation Experiment (CANAPE) and Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) oceanographic observations. Deterministic ocean features induce coupling between acoustic modes confined to the Beaufort duct and non-ducted modes by weakening the duct or causing it to take on an asymmetric form. A non-dimensional mode interaction parameter (MIP) can be defined using the acoustic frequency and the vertical and horizontal scales of sound speed perturbation to characterize coupling strength. It identifies three important wave propagation regimes: sudden approximation, adiabatic approximation, and maximum interaction regime (Colosi and Zinicola-Lapin, 2021). When the MIP between ducted and lossy modes is more and less than 1, strong and weak acoustic variability is predicted, respectively. Variability is high when the MIP between two ducted modes surpasses 1, but modei–mode interference patterns grow more complicated. Acoustic numerical simulations are used to demonstrate various effects.

Mechanism of diffusion promotion of carbon atoms during carburization of 20Cr2Ni4A alloy steel after lanthana-bearing supersonic fine particle bombarding pretreatment

Alloyed layer with gradient structure was prepared on the surface of 20Cr2Ni4A steel by lanthana-bearing supersonic fine particle bombarding (SFPB). Microstructure features of the surface layer were characterized. Subsequently, the samples were carburized in an ECM vacuum furnace. Based on the experimental observations, the mechanism of promoting the diffusion of carbon atoms by lanthana-bearing SFPB was proposed. It mainly involves the promotion of the structure obtained by lanthana-bearing SFPB on the adsorption and diffusion of carbon atoms during carburization. The promotion mechanism of the rare earth in the alloying layer on carbon atom diffusion was analyzed from the aspects of accelerating mechanism of carbon source decomposition by rare earth, subsurface diffusion channel mechanism and driving force. Experimental evidence and related mechanisms show that, the structure formed by the step of austenitization during carburization and the existence of rare earth are necessary to promote the diffusion of carbon atoms. Therefore, our research results clarify the promotion mechanism of lanthana-bearing SFPB treatment on the diffusion of carbon atoms in the carburizing process, and further useful to adjust the surface structure to promote the application of pretreatment technology in surface modification.

Data-driven edge detectors for seismic data interpretation

We have developed a novel method to assist in seismic interpretation. The algorithm learns data-driven edge detectors for structure enhancement when applied to time slices of 3D poststack seismic data. We obtain the operators by distilling the local and structural information retrieved from patches taken randomly from the input time slices. The filters conform to an orthogonal family that behaves as structure-aware Sobel-like edge detectors, and the user can set their size and number. The results from marine Canada and New Zealand 3D seismic data demonstrate that our algorithm allows the semblance attribute to improve the delineation of subsurface channels. This fact is further supported by testing the method with realistic synthetic 2D and 3D data sets containing channeling and meandering systems. We contrast the results with standard plain Sobel filtering, multidirectional Sobel filters of variable size, and the dip-oriented plane-wave destruction Sobel attribute. Our method gives results that are comparable or superior to those of Sobel-based approaches. In addition, the obtained filters can adapt to the geologic structures present in each time slice, which reduces the number of unwanted artifacts in the final product.