Geophysical data fusion by fuzzy logic for imaging the mechanical behaviour of mudslides

2007 ◽  
Vol 178 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Gilles Grandjean ◽  
Jean-Philippe Malet ◽  
Adnand Bitri ◽  
Ombeline Méric
Keyword(s):  
Electrical Resistivity ◽  
Data Fusion ◽  
Cross Sections ◽  
Geophysical Methods ◽  
Geophysical Data ◽  
Physical Parameters ◽  
Seismic Velocities ◽  
S Wave ◽  
S Waves ◽  
Resistivity Data

Abstract Geophysical methods such as seismic surveying or electrical resistivity imaging appear to be well adapted to investigate landslide structure and understand related mechanisms. They allow direct and non-intrusive measurements of acoustic (P), shear (S) waves velocity and electrical resistivity, three physical parameters considered as essential to define the properties of reworked moving materials. Both methods were applied at the “Super-Sauze” site, in the French South Alps, where a typical example of an intra-material mudslide can be observed. Measurements were taken simultaneously along a profile of 325 m in length, perpendicularly to the axis of the mudslide. The P and S-wave velocity fields, as well as the electrical resistivity field, were inverted from recorded data according to suitable algorithms. P and S-wave velocities as well as resistivity tomographies are presented and discussed in term of reliability. Preliminary interpreted results show a correlation between the seismic velocities and electrical resistivity data, confirming that the simultaneous use of both methods gives complementary information on the geomechanical behaviour of the landslide. The seismic data provide information on the variations of fissure density and on the presence of deformed material whereas the electrical resistivity data provide information on the variations of water content within the mudslide. In order to go deeper into the interpretation of the geomechanical behaviour of the mudslide from geophysical data, a data fusion strategy based on fuzzy subsets theory is developed. The computed fuzzy cross-sections show the possibility of geomechanical hypotheses to be realized in specific areas of the tomographic cross-sections highlighting the places where plastic or solid-body deformations could occur. This information is consistent with the geotechnical data and the borehole inclinometer measurements available for the mudslide.

Multiphysics anomaly map: A new data fusion workflow for geophysical interpretation

2020 ◽  
Vol 8 (2) ◽  
pp. B35-B43
Author(s):  
Julio Cesar S. O. Lyrio ◽  
Paulo T. L. Menezes ◽  
Jorlivan L. Correa ◽  
Adriano R. Viana
Keyword(s):  
Data Fusion ◽  
Geophysical Methods ◽  
Real Data ◽  
Logistic Function ◽  
Geophysical Data ◽  
Data Set ◽  
Geophysical Interpretation ◽  
Wide Range ◽  
Anomaly Map ◽  
Different Response

When collecting and processing geophysical data for exploration, the same geologic feature can generate a different response for each rock property being targeted. Typically, the units of these responses may differ by several orders of magnitude; therefore, the combination of geophysical data in integrated interpretation is not a straightforward process and cannot be performed by visual inspection only. The multiphysics anomaly map (MAM) that we have developed is a data fusion solution that consists of a spatial representation of the correlation between anomalies detected with different geophysical methods. In the MAM, we mathematically process geophysical data such as seismic attributes, gravity, magnetic, and resistivity before combining them in a single map. In each data set, anomalous regions of interest, which are problem-dependent, are selected by the interpreter. Selected anomalies are highlighted through the use of a logistic function, which is specially designed to clip large magnitudes and rescale the range of values, increasing the discrimination of anomalies. The resulting anomalies, named logistic anomalies, represent regions of large probabilities of target occurrence. This new solution highlights areas where individual interpretations of different geophysical methods correlate, increasing the confidence in the interpretation. We determine the effectiveness of our MAM with application to real data from onshore and offshore Brazil. In the onshore Recôncavo Basin, the MAM allows the interpreter to identify a channel where a drilled well found the largest sandstone thickness on the area. In a second example, from offshore Sergipe-Alagoas Basin, the MAM helps differentiate between a dry and an oil-bearing channel previously outlined in seismic data. Therefore, these outcomes indicate that the MAM is a valid interpretation tool that we believe can be applied to a wide range of geologic problems.

scholarly journals Investigation of Dimension Stone on the Island Brač—Geophysical Approach to Rock Mass Quality Assessment

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 112 ◽  
Author(s):  
Jasmin Jug ◽  
Kristijan Grabar ◽  
Stjepan Strelec ◽  
Filip Dodigović
Keyword(s):  
Electrical Resistivity ◽  
Rock Mass ◽  
Geophysical Methods ◽  
Dimension Stone ◽  
Seismic Velocities ◽  
Good Tool ◽  
Rock Mass Structure ◽  
Rock Mass Quality ◽  
Refraction Seismic ◽  
Geophysical Investigations

A site located on the island of Brač is known in history for world-famous architectural stone and stone mining, dating all the way back to ancient Greek and Roman times. The most famous building constructed from the stone from Brač is the Diocletian Cesar Palace in the town Split. Prospective new locations for quarries are still required because the demand for the stone from the island is still high. This paper presents a review of undertaken geophysical investigations, as well as engineering geologic site prospection, with the purpose of determining if the rock mass quality is suitable for the mining of massive blocks needed for an architectural purpose—dimension stones. Several surface noninvasive geophysical methods were applied on the site, comprising of two seismic methods, multichannel analysis of surface waves (MASW) and shallow refraction seismic (SRS) electrical methods of electrical resistivity tomography (ERT), as well as electromagnetic exploration with ground penetrating radar (GPR). Results of geophysical investigations were compared to the engineering geologic prospection results, as well to the visible rock mass structure and observed discontinuities on the neighboring existing open mine quarry. Rock mass was classified into three categories according to its suitability for dimension stone exploitation. Each category is defined by compressional and shear seismic velocities as well as electrical resistivity. It has been found that even small changes in moisture content within the large monolithic rock mass can influence measured values of electrical resistivity. In the investigated area, dimension stone quarrying is advisable if the rock mass has values of resistivity higher than 3000 Ωm, as well as compressional seismic velocities higher than 3000 m/s and shear wave velocities higher than 1500 m/s. Georadar was found to be a good tool for the visual determination of fissured systems, and was used to confirm findings from other geophysical methods.

Tomographic imaging of permafrost using three-component seismic cone-penetration test

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. H55-H65 ◽  
Author(s):  
Anne-Marie LeBlanc ◽  
Richard Fortier ◽  
Calin Cosma ◽  
Michel Allard
Keyword(s):  
Tomographic Imaging ◽  
Unfrozen Water ◽  
Seismic Velocities ◽  
S Wave ◽  
Cone Penetration ◽  
Arrival Times ◽  
S Waves ◽  
Seismic Properties ◽  
Unfrozen Water Content ◽  
First Arrival

We conducted seismic cone-penetration tests (SCPT) and tomographic imaging in a permafrost mound in northern Quebec, Canada, to study the cryostratigraphy and assess the seismic properties of permafrost at temperatures near [Formula: see text]. A swept impact source generating both P- and S-waves and penetrometer-mounted three-component accelerometers were used to acquire surface-to-depth first-arrival times as input to produce 2D images of P- and S-wave velocities. Based on the three-component accelerometer records and the propagation modes of body waves, the P- and S-wave first arrivals were detected and discriminated. The inversion of the first-arrival times was based on the simultaneous iterative reconstruction technique. The multioffset surface-to-depth geometry used in this study limits the lateral resolution of tomographic imaging. However, the vertical variation in seismic velocities in the permafrost mound shows good reproducibility and can be compared to the cone data. The gathering of cone data such as cone resistance, friction ratio, electrical resistivity, and temperature, along with the seismic velocities, provides new insights into the cryostratigraphy of permafrost. While the cone data are affected by the vertical heterogeneity because of the complex sequence of ice lenses and frozen soil layers of a few centimeters thickness, the smooth velocity variations of P- and S-waves characterized by a wavelength of a few meters depend on the bulk physical properties of permafrost. The P- and S-wave velocities varied from [Formula: see text] and from [Formula: see text], respectively, for a temperature range between [Formula: see text] and [Formula: see text]. At this temperature range, the variations in unfrozen water content are important and affect directly the seismic properties of permafrost. The decrease in P- and S-waves velocities in depth with the permafrost mound depends nonlinearly on the increase of unfrozen water content from 9% to 30% for a temperature increase from [Formula: see text].

Coupled dynamics of primordial and recycled heterogeneity in Earth's lower mantle, and their present-day seismic signatures

2021 ◽  
Author(s):  
Anna J. P. Gülcher ◽  
Maxim D. Ballmer ◽  
Paul J. Tackley
Keyword(s):  
Oceanic Crust ◽  
Seismic Tomography ◽  
Lower Mantle ◽  
Large Scale ◽  
Numerical Models ◽  
Global Scale ◽  
Physical Parameters ◽  
Compositional Heterogeneity ◽  
Seismic Velocities ◽  
S Wave

<p>The nature of compositional heterogeneity in Earth’s lower mantle is a long-standing puzzle that can inform about the thermochemical evolution and dynamics of our planet. On relatively small scales (<1km), streaks of recycled oceanic crust (ROC) and lithosphere are distributed and stirred throughout the mantle, creating a “marble cake” mantle. On larger scales (10s-100s of km), compositional heterogeneity may be preserved by delayed mixing of this marble cake with either intrinsically-dense or -strong materials of e.g. primordial origin. Intrinsically-dense materials may accumulate as piles at the core-mantle boundary, while intrinsically viscous (e.g., enhanced in the strong mineral MgSiO<sub>3 </sub>bridgmanite) may survive as blobs in the mid-mantle for large timescales (i.e., as plums in the mantle “plum pudding”). So far, only few, if any, studies have quantified mantle dynamics in the presence of different types of heterogeneity with distinct physical properties.<br><br>Here, we use 2D numerical models of global-scale mantle convection to investigate the coupled evolution and mixing of (intrinsically-dense) recycled and (intrinsically-strong) primordial material. We explore the effects of ancient compositional layering of the mantle, as motivated by magma-ocean solidification studies, and the physical parameters of the primordial material. Over a wide parameter range, primordial and recycled heterogeneity is predicted to coexist with each other. Primordial material usually survives as mid-to-large scale blobs in the mid-mantle, and this preservation is largely independent on the initial primordial-material volume. In turn, recycled oceanic crust (ROC) persists as piles at the base of the mantle and as small streaks everywhere else. The robust coexistence between recycled and primordial materials in the models indicate that the modern mantle may be in a hybrid state between the “marble cake” and “plum pudding” styles.<br><br>Finally, we put our model predictions in context with geochemical studies on early Earth dynamics as well as seismic discoveries of present-day lower-mantle heterogeneity. For the latter, we calculate synthetic seismic velocities from output model fields, and compare these synthetics to tomography models, taking into account the limited resolution of seismic tomography. Because of the competing effects of compositional and thermal anomalies on S-wave velocities, it is difficult to identify mid-mantle bridgmanitic domains in seismic tomography images. This result suggests that, if present, bridgmanitic domains in the mid-mantle may be “hidden” from seismic tomographic studies, and other approaches are needed to establish the presence/absence of these domains in the present-day deep Earth.</p>

Mapping groundwater contamination using dc resistivity and VLF geophysical methods–A case study

Geophysics ◽  
1997 ◽  
Vol 62 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Alvin K. Benson ◽  
Kelly L. Payne ◽  
Melissa A. Stubben
Keyword(s):  
Electrical Resistivity ◽  
Cross Sections ◽  
Electromagnetic Induction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Hydrocarbon Contamination ◽  
Monitoring Wells ◽  
Contour Maps ◽  
A Site

Geophysical methods can be helpful in mapping areas of contaminated soil and groundwater. Electrical resistivity and very low‐frequency electromagnetic induction (VLF) surveys were carried out at a site of shallow hydrocarbon contamination in Utah County, Utah. Previously installed monitoring wells facilitated analysis of water chemistry to enhance interpretation of the geophysical data. The electrical resistivity and VLF data correlate well, and vertical cross‐sections and contour maps generated from these data helped map the contaminant plume, which was delineated as an area of high interpreted resistivities.

scholarly journals IMAGING TREE ROOT ZONE GEOMETRY USING ELECTRICAL RESISTIVITY TOMOGRAPHY

2020 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
Asep Mulyono ◽  
Ilham Arisbaya ◽  
Yayat Sudrajat
Keyword(s):  
Electrical Resistivity ◽  
Cross Sections ◽  
Electrical Resistivity Tomography ◽  
Root Zone ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Soil Surface ◽  
Resistivity Tomography ◽  
Root Plate ◽  
Maesopsis Eminii

Root zone geometry research is usually done in a conventional way which is destructive, time-consuming, and requires a considerable cost. Several non-destructive measurements used geophysical methods have been developed, one of which is the Electrical Resistivity Tomography (ERT) method. Tree root zone determination using ERT has been carried out in Kiara Payung area, Sumedang, West Java, with Maesopsis eminii tree as the object study. A total of 29 ERT lines were measured using dipoledipole configuration with electrodes spacing of 50 cm. The results of two-dimensional (2D) and three-dimensional (3D) inversion modeling show that the ERT method has been successfully imaging the tree root zone. The root zone is characterized as 100-700 Ωm with an elliptical shape geometry of the root plate. The root radius is estimated to be 4-5 m from the stem, the root zone diameter reaches 8-9 m at the shallow soil surface and the root zone depth is approximately 2-2.5 m. ABSTRAK Pencitraan geometri zona perakaran pohon menggunakan electrical resistivity tomography. Penelitian geometri zona perakaran biasa dilakukan dengan cara konvensional yang destruktif, memakan waktu, dan membutuhkan biaya yang tidak sedikit. Beberapa pengukuran non-destruktif menggunakan metode geofisika telah dikembangkan, salah satunya adalah metode Electrical Resistivity Tomography (ERT). Penentuan zona perakaran pohon menggunakan metode ERT telah dilakukan di daerah Kiara Payung, Sumedang, Jawa Barat, dengan pohon Maesopsis eminii sebagai objek studi. Sebanyak 29 lintasan ERT diukur menggunakan konfigurasi dipole-dipole pada dengan jarak antar elektroda 50 cm. Hasil pemodelan inversi dua dimensi (2D) dan tiga dimensi (3D) menunjukkan bahwa metode ERT telah berhasil mencitrakan zona perakaran pohon. Zona perakaran teridentifikasi berada pada nilai resistivitas 100-700 Ωm dengan root plate dan root cross-sections berbentuk elips. Radius akar diperkirakan sejauh 4-5 m dari pangkal batang, sedangkan diameter zona perakaran mencapai sekitar 8-9 m di permukaan tanah dangkal dan kedalaman zona perakaran diperkirakan antara ~2-2.5 m. 

scholarly journals COHERENT DESCRIPTION OF ELECTRICAL AND THERMAL IMPURITY–AND–PHONON LIMITED TRANSPORT IN SIMPLE METALS

2001 ◽  
Vol 15 (03) ◽  
pp. 237-257 ◽  
Author(s):  
M. AUSLOOS ◽  
K. DURCZEWSKI ◽  
J. ULNER
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Boltzmann Equation ◽  
Cross Sections ◽  
Transport Coefficient ◽  
Impurity Scattering ◽  
Physical Parameters ◽  
Elastic Electron ◽  
Matrix Elements ◽  
Scattering Cross Sections

The electrical resistivity, thermoelectric power and electronic thermal conductivity of simple (isotropic) metals are studied in a uniform way. Starting from results of a variational solution of the Boltzmann equation, a generalized Matthiessen rule is used in order to superpose the inelastic (or not) electron–phonon and elastic electron–impurity scattering cross sections ("matrix elements"). The temperature dependence relative to these processes is given through simple functions and physical parameters over the usually investigated range of temperature for each transport coefficient. The coherence of such results is emphasized.

The effect of the invaded zone on full wavetrain acoustic logging

Geophysics ◽  
1984 ◽  
Vol 49 (6) ◽  
pp. 796-809 ◽  
Author(s):  
L. J. Baker
Keyword(s):  
The Body ◽  
P Wave ◽  
Physical Parameters ◽  
S Wave ◽  
Acoustic Logging ◽  
S Waves ◽  
Sophisticated Model ◽  
Invaded Zone ◽  
Logging Tool ◽  
Depth Of Investigation

Most theoretical studies of acoustic borehole logging have employed the simple model of a fluid borehole in an infinite solid. This work attempts to account for the invaded zone using a more sophisticated model that additionally includes finite concentric shells surrounding the borehole. By appropriately choosing the physical parameters of these cylindrical shells, one can study the effect of the invaded zone, mudcake, or a cased hole on acoustic wavetrain components. The model accounts for geometric attenuation, but it assumes the formation is perfectly elastic. A key consideration is the distance that the acoustic log “sees” into the formation. The body of this report is devoted to studying the effect of the invaded zone, mudcake, or steel casing on the components of the full wavetrain (P-wave, S-wave, reflected modes, and Stoneley mode). I conclude that a sonic logging tool has a very shallow depth of investigation. This depth, for P- and S-waves, depends upon the spacing between the source and receiver. An approximate rule of thumb is that if the source‐to‐receiver separation is n feet, the logging tool sees n inches into the formation. Thus, a conventional logging tool sees less than 6 inches into the surrounding formation. Since attenuation of the P- and S-wave arrivals places a practical constraint on realistic source‐to‐receiver separations, the depth of investigation is limited to a maximum of about 2 ft. Therefore, an acoustic logging tool is usually capable of measuring properties of the invaded zone only. For the reader interested in the mathematical details of this work, the method of computation is described in Appendix A.

Geotechnical investigation through SP, Electrical Resistivity and GPR geophysical methods

Geotecnia ◽  
2016 ◽  
Vol 137 ◽  
pp. 141-155
Author(s):  
Herson Oliveira da Rocha ◽  
◽  
Lúcia Maria Costa e Silva ◽  
João Andrade dos Reis Júnior ◽  
◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Geotechnical Investigation

Analysis of variations in and correlations between selected physical parameters of common beech (Fagus silvatica L.) nuts

2017 ◽  
Vol 1 (21) ◽  
pp. 49-63
Author(s):  
Zdzisław Kaliniewicz ◽  
Piotr Markowski ◽  
Andrzej Anders ◽  
Paweł Tylek ◽  
Zbigniew Krzysiak ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Correlation Analysis ◽  
Cross Sections ◽  
Linear Regression Analysis ◽  
Physical Parameters ◽  
Common Beech ◽  
Mesh Screen ◽  
Before And After ◽  
Fagus Silvatica ◽  
Highly Correlated

The basic dimensions and the mass of common beech nuts and seeds from five nut batches, harvested from tree stands in northern Poland, were determined. Environmental conditions had a greater influence on seed plumpness than the age of tree stands. The results of measurements were analyzed statistically by analysis of variance, correlation analysis and linear regression analysis. Despite differences in their plumpness, nuts were characterized by nearly identical cross-sections which resembled an equilateral triangle. The thickness of nuts and seeds was highly correlated with their mass, and this information can facilitate seed husking and separation into mass categories. Before and after husking, seeds should be separated with the use of a mesh screen with longitudinal openings. Medium-sized (most numerous) seeds were separated into the following plumpness categories using a screen separator with ≠6 mm and ≠7 mm openings: 84% of moderately plump seeds, 3% of seeds with reduced plumpness, and 13% of plump seeds.

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