Vertical Displacement Amplitude Research Articles

Dynamic response of underreamed batter piles subjected to vertical vibration

ABSTRACT This paper presents the dynamic vertical response of a vertical and two batter piles with an underreamed bulb. Batter angles (i.e. inclination to the vertical) of 10 and 20 degrees have been considered. The dynamic vertical tests were conducted using a mechanical oscillator-motor assembly by varying the intensity of exciting force level with a change in eccentricity setting of the oscillator. The dynamic response was recorded in terms of operating frequency and acceleration response. The test data were analysed to estimate the dynamic vertical responses of the piles in terms of resonant frequency, f y ꞌ; peak vertical displacement amplitude, dyꞌ and axial strain εy , and they were compared. For all three piles, with an increase in intensity of exciting force level, the resonant frequency decreased, whereas the peak vertical displacement and axial strain increased.

Patterns of manifestation of faults of the Pechora-Kolvinsky aulacogen in the radon field

The article presents results of an express radon survey on the territory of the Pechora-Kozhvinsky and Kolvinsky megswells, which are part of the Pechora-Kolvinsky aulacogen. Radon studies were carried out along profiles across the large structure-forming faults, identified on the basis of seismic data. The results show that faults in the radon field correspond to areas with increased values of the radon volumetric activity. In the course of radon studies, main patterns of the manifestation of faults in the radon field were established. The faults may correspond to the maxima of volume activity of radon against the background of low values or to zones with a minimum concentration of radon. In addition, areas with abnormal radon concentrations not associated with known fractures were identified. The systems faults are characterized by wider radon anomalies or alternation of maxima and minima of radon volumetric activity along the profile. The maximum radon concentration is recorded in the fault zones that are closest to the surface, as well as in faults along which large amplitudes of vertical displacements are noted. Similar levels of radon concentration are observed within the normal faults and thrust faults, covered by sedimentary rocks. Most of the studied faults, according to the relative indicator of radon activity, belong to the group of high radon activity. The concentration of radon in the soil air within the faults varies both in the transverse and longitudinal directions. In some areas, the radon volumetric activity of at the same level at different times. This proves the existence of a constant radon flux. The main factors affecting the formation, transport to the surface, and accumulation of radon in the soil are the composition and depth of the basement, the internal structure of fault zones, the degree of porosity and fracturing of rocks and modern geodynamics of the region. Thus, radon survey as an additional method to other geophysical methods can be used to map faults and identify various blocks that differ in fluid-geochemical features.

Cyclic interface behavior of non-water reactive polymer and concrete during dam restoration

In dam restoration engineering, for the differences between material properties from the two sides of the contact surface, complex engineering problems such as excessive shear deformation, separation and sliding of the interface are prone to occur. In this paper, in order to study the mechanical properties of interface between polymer and concrete, the effects of different vertical stresses, shear rates and shear displacement amplitudes were considered, and monotonic direct shear tests and cyclic direct shear tests were conducted by using a newly designed direct shear apparatus. The test results showed that, the polymer-concrete interface shows shear softening in monotonic direct shear and cyclic direct shear tests; when the shear rate and shear displacement amplitude are determined, the average peak shear stress of the polymer-concrete interface shows a good linear relationship with the vertical stress, and the average peak shear stress gradually increases with the increase of vertical stress; with the increase of vertical stress, the shear strength and shear modulus corresponding to the monotonic direct shear and cyclic direct shear tests gradually increased, and the shear strength showed a good linear relationship with the vertical stress; with the increase of shear rate, the shear strength and shear modulus corresponding to the monotonic direct shear and cyclic direct shear tests decrease gradually; the shape of shear stress-displacement curves is remarkably influenced by the shear displacement amplitude.

Paleogeothermal and paleotectonic reconstructions based on vitrinite thermometry data (on the example of the upper paleozoic deposits of the Dnieper-Donets depression and adjacent areas of Donbass)

The article is devoted to paleogeothermal and paleotectonic reconstructions based on the results of processing the vitrinite reflectance data array of coal organic matter of the Upper Paleozoic sediments from the Don-Dnieper Downwarp (within the Dnieper-Donets Depression and adjacent areas of Donbass). It was found that paleogeothermal parameters changed under the influence of geotectonic, magmatic and lithofacies formation conditions of the Upper Paleozoic deposits. Analysis of changes and regularities distribution of paleogeothermal characteristics made it possible to assess the evolution of the thermal field, changes in the tectonic movements character, to identify the role of volcanism, deep faults geodynamics, lithosphere thickness in the thermal history of the region under study. It is shown that with the help of paleostructural analysis, based on data on the thermal maturity degree of coal organic matter, it is possible to judge the activity changes of tectonic structures in time, the formation sequence, to establish the amplitudes of their mutual displacement and rank according to oil and gas potential. Based on the results of the work, maps of the paleogeothermal gradients distribution and the amplitudes of rock masses vertical displacements were constructed. The presented maps should be considered as a universal information material that can be used to determine the features of the regional distribution of the above parameters, as well as become an important tool in the study of tectonic and thermal history, identification changes trends and distribution patterns of paleo­geothermal characteristics.

Diffraction of elastic waves by a fluid-filled crack in a fluid-saturated poroelastic half-space

SUMMARY An indirect boundary element method (IBEM) is developed to model the 2-D diffraction of seismic waves by a fluid-filled crack in a fluid-saturated poroelastic half-space, using Green's functions computed considering the distributed loads, flow and fluid characteristics. The influence of the fluid-filled crack on the diffraction characteristics is investigated by analysing key parameters, such as the excitation frequency, incident angle, crack width and depth, and medium porosity. The results for the fluid-filled crack model are compared to those for the fluid-free crack model under the same conditions. The numerical results demonstrate that the fluid-filled crack has a significant amplification effect on the surface displacements, and that the effect of the depth of the fluid-filled crack is more complex compared to the influence of other parameters. The resonance diffraction generates an amplification effect in the case of normally incident P waves. Furthermore, the horizontal and vertical displacement amplitudes reach 4.2 and 14.1, respectively. In the corresponding case of the fluid-free crack, the vertical displacement amplitude is only equal to 4.1, indicating the amplification effect of the fluid in the crack. Conversely, for normally incident SV waves at certain resonance frequencies, the displacement amplitudes above a fluid-filled crack may be lower than the displacement amplitudes observed in the corresponding case of a fluid-free crack.

Late Quaternary displacements along the Zunduk fault according to ground-penetrating radar and morphostructural analysis (northwestern coast of Lake Baikal)

The article considers the results of GPR studies of the Zunduksky fault section activated between the Cape Oto-Khushun and the Zunduk River, activated in the late Quaternary. The aim of this work is to clarify the kinematic type, determine the vertical displacement amplitudes, and dip angles of the Zunduksky active fault activated in the late Quaternary, as well as determine the maximum magnitude of the earthquake that could occur as a result of the activation of the fault. The work was carried out by OKO-2 GPR with a shielded antenna AB-90 and ABDL-Triton. In addition to the main method, morphostructural analysis of the ledge was used. As a result of the work performed, it was found that the Zunduksky fault in the Late Quaternary was activated under tectonic extension with predominant fault displacement kinematics. The one-act vertical displacements along the seismic fracture change from SW to NE from 6.9 to 1.6 m. When the Late Quaternary ledge of the Zunduksky fault formed, the plastic component of the displacement had a certain value, the contribution of which is from 18 to 78 % of the total displacement. Paleo-earthquake magnitudes calculated from the maximum vertical displacement are Mw = 7.3 and Ms = 7.5.

A UK local seismic magnitude scale, MLP, using P-wave amplitudes

SUMMARYA local seismic magnitude scale, MLP, has been developed for the United Kingdom (UK) using automated measurements of 8902 half peak-to-peak vertical component seismic P-wave displacement amplitudes from 630 earthquakes. The measurement time window increases with source-to-receiver range such that MLP is sensitive to the dominant phase within the P-wavetrain at a given distance. To avoid contamination due to low-frequency noise, the P-wave amplitude measurements are made in the 1.5–30 Hz passband. A least-squares inversion was undertaken to estimate source size, distance and station effects. The distance effect values suggest that P-wave amplitude attenuation across the UK is low when compared to other tectonically stable regions. The station effects are broadly consistent with UK geology, with signal amplification observed within the sediments towards the south-east of the country. MLP has been tied to the UK local magnitude scale routinely estimated by the British Geological Survey (BGS, determined using S waves, and here denoted MLBGS). For earthquakes with MLBGS > 3, MLP exhibits a closer correspondence to the moment magnitude than MLBGS (i.e. MLP≈Mw). It is tentatively suggested that this reduction in bias is caused by the P-wave scale being less affected by along-path attenuation. The difference with respect to physical source scaling helps explain the divergence of the MLBGS and MLP scales at ML > 3. MLP allows a robust estimate of event size to be made for small events which predominantly generate P waves, for example, near-surface explosions. MLP values have been calculated for 239 explosive events, mostly mining blasts and munitions disposal. Although there is significant scatter, explosive events exhibit elevated MLP values compared to MLBGS, consistent with explosions generating proportionally more compressional wave energy than earthquakes. For example, 33 explosions at sea exhibit a median MLP–MLBGS value of 0.50 mag units. Despite its sensitivity to P-wave amplitude, MLP is not a more consistent estimator of explosive source size than MLBGS; the magnitude residuals (station estimate − event estimate) are slightly less for MLBGS compared to MLP. This is primarily due to variability of the P-wave amplitudes that cannot be explained by a 1-D distance correction. MLP should be considered as an additional tool for characterizing small seismic events within the UK.

Late Quarternary displacements along the Sarma segment of the Primorsky fault based on gpr survey data (Baikal rift)

Ground-penetrating radar (GPR) surveys were performed in the Sarma segment of the Primorsky fault between the settlements of Shida and Kurma. This segment belongs to one of the largest structures of the Baikal rift and was active in Late Quaternary (Early Holocene). The study aimed to reconstruct vertical displacement amplitudes and dip angles of fractures along the fault segment, clarify its kinematic type, and estimate a maximum magnitude of earthquakes that may occur in the study area. The GPR equipment set included an OKO-2 georadar and AB-250M and ABDL-Triton shielded antennas. The GPR surveys were supported by morphostructural and tectonophysical methods. Based on the interpretation of the geophysical survey data and satellite images, faults associated with the Sarma paleoseismic dislocation were mapped. Their total length amounts to 14 km. According to the GPR survey data, one-stage vertical displacements show normal faulting and vary from SW to NE from 4.4 to 7.7 m. Paleo-earthquake magnitudes calculated from the maximum displacement values (Mw=7.2, and Мs=7.4) suggest that potential earthquakes in the Primorsky fault zone may be stronger than previously assumed.

Biomechanical quantification of deadbug bridging performance in competitive alpine skiers: Reliability, reference values, and associations with skiing performance and back overuse complaints

Objectives(1) To study the reliability of quantifying rear-chain stabilization capacity during deadbug bridging (DBB), (2) to provide reference values for competitive alpine skiers, and (3) to study associations with age, anthropometrics, maturation, skiing performance and back overuse complaints. DesignCross-sectional. SettingBiomechanical field experiment including questionnaires. Participants12 healthy subjects (reliability experiment); 133 skiers of the U16 category and 38 of the elite category (main experiment). Main outcome measuresDBB performance was quantified using 3D motion capture as the maximum amplitude of the relative vertical displacement of two pelvis markers (DBBdisplacement). Additionally, in U16 skiers, age, anthropometrics, maturation, skiing performance, and back overuse complaints were assessed. ResultsThe reliability experiment revealed an ICC(3,1) and 95% CI of 0.81 [0.61, 0.93]. Within-subject SEM was 3.89 mm [3.16 mm, 5.12 mm]. Depending on sex and category, medians of DBBdisplacement in skiers ranged between 29 mm and 45 mm. DBBdisplacement differed between elite and U16 skiers (p < 0.001), but not between sexes. In U16 skiers, DBBdisplacement was independent of age, anthropometrics, and biological maturation, however, associated with skiing performance and back overuse complaints (p < 0.05). ConclusionThe proposed approach may be considered an adequate method to quantify athletes’ rear-chain stabilization capacity.

Fundamentals of Delineation of Area of Mineral and hot Water Potential in Duyen Hai area, Hung Ha district, Thai Binh Province, Viet Nam for Exploration Purpose

Mineral and hot water is a valuable resource that can be used for nursing and physiotherapy, making bottled water, making beverage and healing, exploiting useful minerals, energy extraction, even cultivation spirulina and other purposes. Hot groundwater was discovered during the 90s of the 20th century in Duyen Hai commune, Hung Ha district, Thai Binh province, but no exploration and evaluation studies were conducted to determine the potential of the mineral and hot water in the area. Spatial distribution of groundwater temperature and the total mineralization in the study area of the mineral and hot water occurrence and its surrounding area has allowed to identify the area of mineral and hot water origin, and that the hot water belongs to average hot water with a temperature of about 49 degrees Celsius. Analyzing the tectonic structure has showed that the mineral and hot water is formed at an area surrounded by three class-2 faults, which have a vertical displacement amplitude of 100 m - 1,000 m and a destructive zone of over 100 m. This is an area with favorable conditions to bring geothermal source and dissolved minerals in surrounding rocks to groundwater in the above aquifers. The approach presented in the paper can be applied to conduct research on potential mineral and hot water in other areas: determine values of some mineral and hot water parameters such as temperature and TDS, compile maps of spatial distribution of the parameters, clarify characteristics of tectonic structure relevant to anomaly of high temperature and TDS.

Horizontal and vertical motion at the surface of swelling poroelastic layer sandwiched between water and elastic solid

The horizontal and vertical motions at the surface of swelling poroelastic layer in coupled system are investigated. Coupled system means water-swelling porous sediment-elastic solid substrate system. The analytical expressions of horizontal and vertical displacements at the surface of swelling porous solid are evaluated for both incidences i.e., P and SV waves. The closed form analytical expressions for reflection and transmission coefficients are derived theoretically for appropriate boundary conditions. The horizontal and vertical displacement amplitudes are derived analytically in terms of reflection and transmission coefficients. The horizontal and vertical motion of swelling poroelastic layer is examined through analyzing three key factors: amplification coefficients, displacement amplitudes and displacement ratio. The impacts of wave frequency, thickness of swelling poroelastic layer, incident direction and swelling property of the medium are examined on these three key factor numerically. Numerical results indicate that the surface motion strongly depends on wave frequency, thickness of layer, swelling property of the medium and incident direction.

Riders Use Their Body Mass to Amplify Crank Power during Nonseated Ergometer Cycling

To date, neither the CoM movement strategies during nonseated cycling nor the limb mechanics that allow this phenomenon to occur have been quantified. Here we estimate how much power can be contributed by a rider's CoM at each instant during the crank cycle by combining a kinematic and kinetic approach to measure CoM movement and joint powers of 15 participants riding in a nonseated posture at three individualized power outputs (10%, 30%, and 50% of peak maximal power) and two different cadences (70 and 120 rpm). The peak-to-peak amplitude of vertical CoM displacement increased significantly with power output and with decreasing cadence. Accordingly, the greatest peak-to-peak amplitude of CoM displacement (0.06 ± 0.01 m) and change in total mechanical energy (0.54 ± 0.12 J·kg) occurred under the combination of high-power output and low cadence. At the same combination of high-power output and low cadence, we found that the peak rate of CoM energy loss (3.87 ± 0.93 W·kg) was equal to 18% of the peak crank power. Consequently, it appears that for a given power output, changes in CoM energy contribute to peak instantaneous power output at the crank, thus reducing the required muscular contribution. These findings suggest that the rise and fall of a rider's CoM acts as a mechanical amplifier during nonseated cycling, which has important implications for both rider and bicycle performance.

Application of 1-D and 2-D Discrete Wavelet Transform to Crack Identification in Statically and Dynamically Loaded Plates

The paper presents the problem of damage detection in thin plates while considering the influence of static and dynamic characteristics, especially with regard to the modes of vibration as well as the excitation by static loads. The problem of Kirchhoff plate bending is described and solved by the Boundary Element Method (BEM). Rectangular plates supported on boundary or plates supported on boundary and resting on the internal columns are examined. A defect is introduced by the additional edges forming a crack in the plate domain. The analyses of static and dynamic structural responses are carried out with the use of Discrete Wavelet Transform (DWT). Signal decomposition according to the Mallat pyramid algorithm is applied. To obtain a more adequate input function subjected to DWT the white noise disturbing the signal is considered together with the structural response. In the dynamic experiments the plate undergoes vibrations similar to natural modes. The measured variables are static deflections and vertical displacement amplitudes. All of them are established at internal collocation points distributed alongside the line parallel to selected plate edge.

Design of optimum vibration absorbers for a bus vehicle to suppress unwanted vibrations against the harmonic and random road excitations

Unwanted vibrations of the vehicles are regarded as harmful threats to the human health from various biomechanical and psychophysical aspects. Road roughness has been considered as the main cause of unwanted vibrations in bus vehicles. Vertical seat vibrations have been found via simulation of a ten degree of freedom (10-DOF) model of an intercity bus vehicle under harmonic and random excitations caused by road roughness. To suppress undesirable vibrations, mass-spring-damper passive absorbers are proposed in a thirteen degrees of freedom (13-DOFs) model of the bus. By optimizing the characteristics of the embedded passive absorbers under each seat, and implementation of the designed absorbers, it is observed that the vertical displacement amplitudes in the frequency response of the seats are reduced especially near the bus resonance frequencies. In addition, the vertical displacement and acceleration amplitudes are decreased in the random excitation of the road roughness. According to the results, optimized mass-spring-damper absorbers are suggested as a practical solution to suppress the unwanted vibration effects in the bus vehicle.

M-shaped flame dynamics

This article deals with the dynamics of a cylindrical bluff-body-stabilized M-shaped premixed flame at low flow rates. A comparative analysis with classical conical flames was performed. The velocities and flame front field dynamics were studied with the use of numerical methods. It was shown that the processes under the investigation are similar to those in a conical flame. The flame front is deformed by moving Kelvin–Helmholtz vortices along the front. It was found that M-shaped flame tips perform in-phase low-frequency oscillations in both vertical and horizontal directions as opposed to the conical one. It was also found that fuel enrichment does not affect the frequency of the flicker as compared to the classical conical flame. A number of experiments have shown that vertical displacement amplitude in M-shaped flame is approximately 3.5 times smaller than in a conical one at the same flow rate. An explanation of this phenomenon is the fact that a part of the energy under compression goes to the horizontal displacement of the front.

Analytical solution of the string vibration model on Sasando musical instrument

This research constructs mathematic model for string vibration on Sasando that expressed as a second-order linear partial differential equation with u denote the vertical displacement experienced by the string at the point x at time t. Besides, the purpose of this research is to determine analytical solution using a method known as separation of variable. There are three analytical solutions from three cases based on constant coefficient values. Case 1 occurs when . Based on he simulation, the string produces a quarter wave within 3 seconds. This means the vibration wavelength 0.083 Hz. In this case the vertical displacement of the string is back to quiescent after vibrating to produce a quarter wave. Case 2 occurs when . The string produces 3.5 waves within 3 seconds, means the vibration wavelength is 1.67 Hz. In this case, the farthest vertical displacement (amplitude) become smaller drastically and back to quiescent. Case 3 occurs when . The vibration wavelength of the string is 2.83 Hz, with 7.5 waves within 3 seconds. The vertical displacement decreases periodically and back to quiescent at a certain time. Analysis of 2-dimensional graph for vertical displacement u(x,t) is done with n = 1,2,3,4,5 which is compared with profile of u(x,t) Gulla (2011). Based on results of the model were mentioned before, the mathematical model of string vibration on Sasando has the similar profile as Gulla (2011). For further, this research is suggested to perform a graph profile analysis of other cases that may arise with variation of parameter values.

Ross Ice Shelf Icequakes Associated With Ocean Gravity Wave Activity

AbstractGravity waves impacting ice shelves illicit a suite of responses that can affect ice shelf integrity. Broadband seismometers deployed on the Ross Ice Shelf, complemented by a near‐icefront seafloor hydrophone, establish the association of strong icequake activity with ocean gravity wave amplitudes (AG) below 0.04 Hz. The Ross Ice Shelf‐front seismic vertical displacement amplitudes (ASV) are well correlated with AG, allowing estimating the frequency‐dependent transfer function from gravity wave amplitude to icefront vertical displacement amplitude (TGSV(f)). TGSV(f) is 0.6–0.7 at 0.001–0.01 Hz but decreases rapidly at higher frequencies. Seismicity of strong icequakes exhibits spatial and seasonal associations with different gravity wave frequency bands, with the strongest icequakes observed at the icefront primarily during the austral summer when sea ice is minimal and swell impacts are strongest.

Dynamic analysis of layered systems under a moving harmonic rectangular load based on the spectral element method

In order to design high-performance roadways, a robust tool which can compute the structural response caused by moving vehicles is necessary. Therefore, this paper proposes a spectral element method-based model to accurately and effectively predict the 3D dynamic response of layered systems under a moving load. A layer spectral element and a semi-infinite spectral element are developed to respectively model a layer and a half-space, and the combinations of these two elements can simulate layered systems. The detailed mathematical derivation and numerical validation of the proposed model are included. Additionally, this model is used to investigate the dynamic characteristics of a pavement structure under a moving harmonic rectangular load. The results show that the proposed model can accurately predict the dynamic response of layered systems caused by a moving load. It is also found that the vertical displacement amplitude curves of surface points caused by a moving harmonic load are asymmetric along the moving direction, and this property is more dominant at higher velocities. In addition, the amplitudes of these vertical displacements are smaller if the loading frequency is higher or the loss factor is bigger. Finally, the loading area and Poisson's ratio only have effect on the displacement amplitudes of points in the close vicinity of the loading area. The proposed model is beneficial to the development of engineering methods for pavement design and is a promising parameter back-calculation engine for pavement quality evaluation.

Testing the performance of earthquake early warning system in northern India

The main goal of present study is to test the functionality of an earthquake early warning (EEW) system (a life-saving tool), in India using synthesized data and recorded earthquake data from Taiwan. In recent time, India set up an EEW system in the central seismic gap along the Himalayan Belt, consisting of about 100 low-cost P-Alert instruments. The area, where these instruments are installed, is highly sensitive to the seismic risk with the potential of strong, major and great earthquakes. In the absence of recorded data from the Himalayas required for analysis of such system, we take advantage of recorded waveforms from Taiwan, to test the EEW system. We selected Taiwanese stations in good accordance with the Indian sensor network, to have a best fit in terms of inter station spacing. Finally, the recorded waveforms are passed through Earthworm software using tankplayer module. The system performs very well in terms of earthquake detection, P-wave picking, earthquake magnitude and location (using previously estimated regressions). Pd algorithm has been tested where the peak amplitude of vertical displacement is used for estimating magnitudes using previously regressed empirical relationship data. For the earthquakes located between Main Boundary Thrust and Main Central Thrust along with a matching instrumentation window, a good estimate of location, as well as magnitude is observed. The approach based on Pd for estimating magnitude works perfectly as compared to $$\tau_{\text{c}}$$ approach, which is more sensitive to signal-to-noise ratio. To make it more region specific, we generated synthetic seismograms from the epicenters of historical Chamoli (1999) and Uttarkashi (1991) earthquakes at EEW stations in India and checked the functionality of EEW. While placing these earthquakes within the instrumentation window, a good approximation of earthquake location and magnitude is obtained by passing these generated waveforms. The parameters used to judge the performance of EEW system included the time taken by the system in issuing warning after the confirmation of the occurrence of damaging earthquake and the lead time (time interval between the issuing of warning and arrival of damaging earthquake ground motion at a particular location). High lead times have been obtained for the plainer regions including thickly populated regions of Gangetic plains, such as Delhi National Capital Region according to the distance from the epicenter, which are the main target of EEW system.

Effect of geometry on in-plane responses of a symmetric canyon subjected by P waves

Topographic site effects in anti-plane problems have been studied for four decades cause of the obtained analytical solutions. The authors have developed proposed hybrid methods combining Lamb's series with finite element method (FEM) to resolve the problem of anti-plane scattering; however, it has been difficult to account for site effects in in-plane problems due to mode conversion. In this study, we sought to resolve this issue by developing a novel hybrid method to investigate the site effects of a canyon subjected to longitudinal waves (P waves) as well as horizontal and vertical displacement amplitudes (|ux| and |uz|) near and along canyons of various shapes. A transfinite interpolation function (TFI) was used to obtain the coordinates of nodes and conduct node numbering in the inner finite region within the canyon. Combining hybrid method with TFI function, similar procedures can be used to resolve the scattering problems in both anti-plane and in-plane problems.Canyons are divided into three groups according to shape: 1) smooth shallow, 2) non-smooth, and 3) smooth deep. We also examine the incident angle of P waves (θ), the dimensionless frequencies (η), and the shape of a canyon in terms of their effect on |ux| and |uz|. These factors were shown to generate site effects, including canyon-decay-effect, oblique-effect, shield effect, and SDCP (slope discontinuous points) effect. The site effects induce variations in |ux| and |uz| with constructive interference in the illuminated zone, destructive interference in the shadow zone, and attenuation along the surface of the canyon.