scholarly journals Influence of Temperature on Quantification of Mesocracks: Implications for Physical Properties of Fine-Grained Granite

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Zhu Chun ◽  
Lin Yun ◽  
Feng Gan
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Crack Density ◽  
P Wave ◽  
Optical Observations ◽  
Thin Sections ◽  
Thermally Induced ◽  
Fine Grained ◽  
P Wave Velocity ◽  
And Performance

Abstract Thermally induced changes in mesocrack and the physical properties of fine-grained granite may influence their stability, transport characteristics, and performance related to various deep subsurface energy projects. In this study, granite was heat-treated at different temperatures (20°C, 100°C, 200°C, 300°C, 400°C, 500°C, and 600°C). The propagation and evolution of different types of cracks and the physical properties of the granite were quantitatively investigated, using optical observations of petrographic thin sections, P-wave velocity measurements, and permeability tests. The results show that as the temperature increased, the number and length of cracks increased, and the cracks were randomly distributed in all directions. This led to an increase in rock damage (λn) and an increase in permeability (K). In particular, when the temperature was ≥400°C, the damage rate significantly increased, and the number and length of intragranular cracks significantly exceeded the number and length of intergranular cracks. This led to changes in the permeation path, causing it to mainly travel through the interior of mineral particles. Using the inverse of P-wave velocity (VP), the dimensionless crack density (ρ) of granite was found to increase as the temperature increased, and this result was similar to the change of optical crack density (Pl). These analyses laid a reference for understanding the correlation between microcrack characteristics and macrophysical properties of granite.

scholarly journals Correlation of P-wave velocity with mechanical and physical properties of limestone with statistical analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hasan Arman
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Point Load ◽  
P Wave ◽  
Unit Weight ◽  
Empirical Equations ◽  
Thin Sections ◽  
X Ray ◽  
P Wave Velocity ◽  
Mechanical And Physical Properties

AbstractThis study aims to investigate the correlation between the P-wave velocity (Vp) and the mechanical and the physical properties of the limestone; Vp tests were conducted on over 320 limestone samples. Moreover, the effects of the mineralogical, textural, and chemical composition of limestone were also studied through thin sections, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The relationships between the Vp and the uniaxial compressive strength (UCS), point load index (PLI(Is(50)), 2nd cycle of slake durability index (Id2), natural unit weight (γn), specific gravity (Gs(c)), water absorption by weight (WA), and porosity (n) were estimated using representative empirical equations. The empirical equations were validated by Student’s t test that has indicated the existence of strong relationships between the mechanical and physical properties of the intact limestone with Vp; the calculated t-values were higher than the t-critical value. Furthermore, the results of previously available studies were compared with the results of this study in terms of the generated equations for Vp values and the slope of a 1:1 line, which was used to appraise the predicted and measured values. This study demonstrates that the UCS, PLI(Is(50)), Id2, γn, Gs(c), WA, and n values of an intact limestone can be predicted by using Vp, which is fast, easy, economical and nondestructive test.

Multiscale fracture density analysis at Stromboli Volcano, Italy: implications to flank stability

2021 ◽  
Author(s):  
Thomas Alcock ◽  
Sergio Vinciguerra ◽  
Phillip Benson ◽  
Federico Vagnon
Keyword(s):  
Electrical Resistivity ◽  
Wave Velocity ◽  
Rift Zone ◽  
Pulse Generator ◽  
Average Length ◽  
Crack Density ◽  
P Wave ◽  
Fracture Density ◽  
Stromboli Volcano ◽  
P Wave Velocity

<p>Stromboli volcano has experienced four sector collapses over the past 13 thousand years, resulting in the formation of the Sciara del Fuoco (SDF) horseshoe-shaped depression and an inferred NE / SW striking rift zone across the SDF and the western sector of the island. These events have resulted in the formation of steep depressions on the slopes on the volcano where episodes of instability are continuously being observed and recorded. This study aims to quantify the fracture density inside and outside the rift zone to identify potential damaged zones that could reduce the edifice strength and promote fracturing. In order to do so we have carried out a multiscale analysis, by integrating satellite observations, field work and seismic and electrical resistivity analyses on cm scales blocks belonging to 11 lava units from the main volcanic cycles that have built the volcano edifice, ie. Paleostromboli, Nestromboli and Vancori. 0.5 m resolution Pleiades satellite data has been first used to highlight 23635 distinct linear features across the island. Fracture density has been calculated using Fracpaq based on the Mauldon et al (2001) method to determine the average fracture density of a given area on the basis of the average length of drawn segments within a predetermined circular area. 41.8 % of total fracture density is found around intrusions and fissures, with the summit area and the slopes of SDF having the highest average fracture density of 5.279  . Density, porosity, P- wave velocity in dry and wet conditions and electrical resistivity (in wet conditions) were measured  via an ultrasonic pulse generator and acquisition system (Pundit) and an on purpose built measuring quadrupole on cm scale blocks of lavas collected from both within and outside the proposed rift zone to assess the physical state and the crack damage of the different lava units.  Preliminary results show that P-wave velocity between ~ 2.25 km/s < Vp < 5km/s decreases with porosity while there is high variability electrical resistivity with 21.7 < ρ < 590 Ohm * m. This is presumably due to the lavas texture and the variable content of bubble/vesicles porosity and crack damage, that is reflected by an effective overall porosity between 0 and 9 %. Higher porosity is generally mirrored by lower p-wave velocity values. Neostromboli blocks show the most variability in both P-wave velocity and electrical resistivity. Further work will assess crack density throughout optical analyses and systematically investigate the UCS and elastic moduli. This integrated approach is expected to provide a multiscale fracture density and allow to develop further laboratory testing on how slip surfaces can evolve to a flank collapse at Stromboli.</p>

The Heritage Stone of Nossa Senhora de Guadalupe Church, Mouçós, North of Portugal: Characterisation and Glyptography

2021 ◽  
Author(s):  
David Freire-Lista ◽  
Bruno Campos ◽  
Patricia Moreira da Costa
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Wave Velocity ◽  
Effective Porosity ◽  
P Wave ◽  
Building Stones ◽  
Thin Sections ◽  
P Wave Velocity ◽  
The Mean ◽  
The Church

<p>Granite is the most important building stone in the north of Portugal. The importance of the stones in this region is evidenced by the pre-Roman roots Mor (r), Mur (r) and Mour of place names such as Montemuro, Moreiras, Mouçós, and Mourelhe. These roots indicate the existence of building stones used since ancient times in these places.</p><p>The quarries of the main building stones of historical buildings were generally in the vicinity of the buildings. Formerly, stonemasons carved mason's marks on ashlars. The mason's marks are lapidary signs to indicate the work carried out by each one. The mason's marks are generally symbolised by the initial of the stonemason's name. They are often found on dressed stones in buildings and in other public structures.</p><p>Nossa Senhora de Guadalupe church of Mouçós (possibly 16<sup>th</sup> century) has typical characteristics from the late Romanesque. It is located in Vila Real (North of Portugal). It is made up of three volumes: a single nave, a lower rectangular apse, and a sacristy attached to the apse. The exterior of this church is preserved almost unaltered in its original state. Each of the granite ashlars that make up this church has a mason's mark in the center of its face.</p><p>The mason's marks of the church have been identified; all the ashlars with visible mason's marks have been mapped, and a glyptographic study has been carried out. This has made it possible to calculate the number of stonemasons that worked in the construction of the church and the number of ashlars that were transported in each carriage, and to determine the construction phases of the church.</p><p>Eight cubic samples have been cut to calculate the granite’s hydric properties (effective porosity, water absorption and bulk density) according to UNE-EN:1936. Ultrasound wave velocity was measured according to UNE-EN:14579. Furthermore, three thin sections have been made to characterise the granite petrographically under a polarisation microscope Leica DM-4500-P. A mosaic of photomicrographs has been made to evaluate the petrographic properties.</p><p>There are six main types of mason's marks in Nossa Senhora de Guadalupe Church. All quarrymen extracted the stones from the same quarry, or from nearby quarries. The mean effective porosity of the building granite is 3.2%±0.3, and the mean water absorption is 1.2%±0.1. Its mean bulk density is 2566 kg/m<sup>3</sup>±61.0 and its ultrasound P wave velocity is 2920 m/s±98.3.</p><p>The mason's marks are preserved because of the excellent petrographic and petrophysical properties of Mouçós granite. Further, Nossa Senhora de Guadalupe church was protected with lime plaster during the past centuries, and the plaster was not removed with the projection of abrasive particles.</p><p>The use of analytical techniques such as petrography, ultrasonic P wave velocity and the determination of hydric properties will guarantee the quality and durability of a sustainable restoration.</p><p>The historical quarries, forms of traditional stone extraction and uses of Mouçós granite constitute a heritage that must be safeguarded.</p><p>Acknowledgements: The Fundação para a Ciência e a Tecnologia (FCT) of Portugal. CEECIND/03568/2017.</p>

scholarly journals Semiglobal viscoacoustic full-waveform inversion

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. R271-R293 ◽  
Author(s):  
Nuno V. da Silva ◽  
Gang Yao ◽  
Michael Warner
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Seismic Data ◽  
Waveform Inversion ◽  
P Wave ◽  
Full Waveform Inversion ◽  
Data Set ◽  
Intrinsic Attenuation ◽  
Full Waveform ◽  
P Wave Velocity

Full-waveform inversion deals with estimating physical properties of the earth’s subsurface by matching simulated to recorded seismic data. Intrinsic attenuation in the medium leads to the dispersion of propagating waves and the absorption of energy — media with this type of rheology are not perfectly elastic. Accounting for that effect is necessary to simulate wave propagation in realistic geologic media, leading to the need to estimate intrinsic attenuation from the seismic data. That increases the complexity of the constitutive laws leading to additional issues related to the ill-posed nature of the inverse problem. In particular, the joint estimation of several physical properties increases the null space of the parameter space, leading to a larger domain of ambiguity and increasing the number of different models that can equally well explain the data. We have evaluated a method for the joint inversion of velocity and intrinsic attenuation using semiglobal inversion; this combines quantum particle-swarm optimization for the estimation of the intrinsic attenuation with nested gradient-descent iterations for the estimation of the P-wave velocity. This approach takes advantage of the fact that some physical properties, and in particular the intrinsic attenuation, can be represented using a reduced basis, substantially decreasing the dimension of the search space. We determine the feasibility of the method and its robustness to ambiguity with 2D synthetic examples. The 3D inversion of a field data set for a geologic medium with transversely isotropic anisotropy in velocity indicates the feasibility of the method for inverting large-scale real seismic data and improving the data fitting. The principal benefits of the semiglobal multiparameter inversion are the recovery of the intrinsic attenuation from the data and the recovery of the true undispersed infinite-frequency P-wave velocity, while mitigating ambiguity between the estimated parameters.

scholarly journals Combined controls of sedimentology and diagenesis on seismic properties in lacustrine and palustrine carbonates (Upper Miocene, Samos Island, Greece)

2019 ◽  
Vol 219 (2) ◽  
pp. 1300-1315 ◽  
Author(s):  
C Bailly ◽  
M Adelinet ◽  
Y Hamon ◽  
J Fortin
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Mineralogical Composition ◽  
Sedimentary Facies ◽  
P Wave ◽  
Seismic Properties ◽  
Diagenetic Processes ◽  
P Wave Velocity ◽  
Seismic Reflectors

SUMMARY For the subsurface characterization of carbonates, linking physical properties (e.g. porosity and seismic reflectors) with their geological significance (e.g. sedimentary facies and diagenesis) is of primary importance. To address this issue, we study the lacustrine and palustrine carbonates on Samos Island through a geological and geophysical characterization of a sedimentary succession. The microstructures of the samples are described, and the samples’ physical properties are measured (porosity, P-wave velocity and density). The results show that the identification of only the primary (i.e. sedimentary) microstructure is not sufficient for explaining the huge variations in porosity and P-wave velocity. Hence, we highlight two early diagenetic processes that strongly impact the microstructures and control the physical properties: (i) neomorphism occludes porosity and increases the P-wave velocity of mud- and grain-supported microstructures, which implies a mineralogical stabilization of the grains; (ii) conversely, the dissolution process creates porosity and decreases the P-wave velocity of grain-supported microstructures if the mineralogical composition of the grains is not previously stabilized. These two diagenetic processes thus depend on the primary microstructures and mineralogy of the sediments. This work aims to explain the variations in porosity and P-wave velocity for each defined primary microstructure. A 1-D seismogram is then built to highlight seismic reflectors with a metre-scale resolution. These reflectors are associated with several geological contrasts. Hard kicks (positive amplitude reflectors) match well with exposure surfaces related to palaeosols. They correspond to contrasts between non-modified primary microstructures and highly neomorphosed microstructures. Conversely, soft kicks (negative amplitude reflectors) are linked with diagenetic contrasts (e.g. neomorphosed microstructures versus non-modified primary microstructures) and sedimentary contrasts that can be overprinted by diagenesis (e.g. neomorphosed mud-supported microstructures versus dissolved grain-supported microstructures). This study highlights that high-resolution seismic reflectors of lacustrine and palustrine carbonates are strongly related to the spatial contrasts of primary microstructures overprinted by early diagenesis.

scholarly journals Heat-related Changes of Density, P-wave Velocity, and Surface Hardness of Granite

2021 ◽  
Author(s):  
Andor Németh ◽  
Ákos Török
Keyword(s):  
Heat Treatment ◽  
Radioactive Waste ◽  
Physical Properties ◽  
Bulk Density ◽  
Wave Velocity ◽  
Room Temperature ◽  
Surface Hardness ◽  
P Wave ◽  
P Wave Velocity ◽  
Laboratory Test Results

Low- and intermediate-level radioactive waste is stored in the National Radioactive Waste Repository in Bátaapáti in Hungary. The repository is located in the Carboniferous Mórágy Granite Formation. This paper focuses on heat-related changes of physical properties such as bulk density, P-wave velocity, P-wave modulus, and Duroskop surface hardness of the dominant lithology: monzogranite. Cylindrical specimens were tested at laboratory conditions (22 °C) and were heat-treated up to 250 °C, 500 °C, and 750 °C. The properties were measured before and after the thermal strain. After heat-treatment, the monzogranite samples became brownish, and at 750 °C, cracks appear at the surface of the specimens. Laboratory test results show that bulk density values slightly decrease from room temperature to 250 °C treatment and further dropped at 500 °C and especially at 750 °C. P-wave velocity values and the connected P-wave modulus tend to decrease from room temperature to 750 °C significantly. Duroskop rebound values show slight declines in the surface strength of the specimens until 500 °C, and then a drastic decline at 750 °C. Heat treatment tends to alter the physical properties of the monzogranite. From room temperature to 500 °C, a slight but apparent decrease between 500 °C and 750 °C significant reductions in the bulk density, P-wave velocity, and Duroskop values. Behind the physical alterations are the different thermal-induced expansion of minerals and mineral alteration at elevated temperatures.

Study on Volcanic Rock Chemical Composition and Physical Properties in Hainan Province

2013 ◽  
Vol 405-408 ◽  
pp. 1844-1851
Author(s):  
Yong Sheng Yao ◽  
Jian Long Zheng ◽  
Bo Ming Tang ◽  
Hong Zhou Zhu
Keyword(s):  
Chemical Composition ◽  
Physical Properties ◽  
Volcanic Rock ◽  
Wave Velocity ◽  
Volcanic Rocks ◽  
P Wave ◽  
Hainan Province ◽  
S Wave ◽  
X Ray ◽  
P Wave Velocity

In order to study the chemical composition of volcanic rock and physical properties in Hainan province, used the method of X-ray fluorescence, analysises on its chemical composition, and researched the physical properties of volcanic rocks including density test, porosity test, acoustic test, resistance test. The results showed that: the volcanic rock is tholeiitic at the cavity of lava area in Hainan province, P-wave velocity and S-wave velocity would change with the changing of porosity.

Seismic velocities in transversely isotropic media

Geophysics ◽  
1979 ◽  
Vol 44 (5) ◽  
pp. 918-936 ◽  
Author(s):  
Franklyn K. Levin
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Transversely Isotropic ◽  
P Wave ◽  
Seismic Velocities ◽  
Sh Wave ◽  
Near Surface ◽  
P Wave Velocity ◽  
Unconsolidated Material ◽  
Two Component

When a sedimentary earth section is layered on a scale much finer than the wavelength of seismic waves, the waves average the physical properties of the layers; a seismic wave acts as if it were traveling in a single, transversely isotropic solid. We compute the velocities with which P‐waves, SV‐waves, and SH‐waves travel in transversely isotropic solids formed from two‐component solids and find the corresponding moveout velocities from [Formula: see text] plots. The combinations studied are sandstone and shale, shale and limestone, water sand and gas sand, and gypsum and unconsolidated material, one set of typical physical properties being selected for each component of a combination. A reflector at 1524 m and a geophone spread of 0–3048 m are assumed. The moveout velocity for an SH‐wave is always the velocity for a wave traveling in the horizontal direction. The P‐wave moveout velocity found from surface seismic data can be anywhere from the vertical P‐wave velocity to values between those for vertical and horizontal travel; the actual value depends on the elastic parameters and the spread length used for velocity determination. If the two components of the solid have the same Poisson’s ratio, the velocity from surface‐recorded data is the vertical P‐wave velocity. For this case, SH‐wave anisotropy can be computed. SV‐wave data usually do not have hyperbolic time‐distance curves, and the moveout velocity found varies with spread length. Surprisingly, the water sand‐gas sand combination gives a medium with negligible anistropy. A two‐component combination of gypsum in weathered material gives rise to [Formula: see text] plots that seem to explain the unusual behavior of near‐surface SV‐waves seen in field studies reported by Jolly (1956).

Determination of physical properties of carbonate rocks from P-wave velocity

2008 ◽  
Vol 67 (2) ◽  
pp. 277-281 ◽  
Author(s):  
Sair Kahraman ◽  
Tekin Yeken
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Carbonate Rocks ◽  
P Wave ◽  
P Wave Velocity
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