Journal articles: 'MASW'

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Khaheshi Banab, Kasgin, and Dariush Motazedian. "On the Efficiency of the Multi-Channel Analysis of Surface Wave Method for Shallow and Semi-Deep Loose Soil Layers." International Journal of Geophysics 2010 (2010): 1–13. http://dx.doi.org/10.1155/2010/403016.

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The multi-channel analysis of surface waves (MASWs) method was used to obtain the shear wave velocity variations through near surface (depth < 30 m) and semi-deep (30 m < depth < 100 m) soil layers in the city of Ottawa, Canada. Sixteen sites were examined to evaluate the capability of the active and passive MASW methods for cases where the shear wave velocity(Vs)contrast between very loose soil (Vs< 200 m/s) and very firm bedrock (Vs> 2,300 m/s) is very large. The MASW velocity results compared with those of other geophysical approaches, such as seismic reflection/refraction methods and borehole data, where available, mostly confirming the capability of the MASW method to distinguish the high shear wave velocity contrast in the study area. We have found that, of the inversion procedures of MASW data, the random search inversion technique provides better results than the analytical generalized inversion method.

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Miller, Rick, Jianghai Xia, Choon B. Park, and Julian M. Ivanov. "The history of MASW." Leading Edge 27, no. 4 (April 2008): 568. http://dx.doi.org/10.1190/tle27040568.1.

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Hutchinson, Peter J., and Maggie H. Beird. "3D mapping with MASW." Leading Edge 35, no. 4 (April 2016): 350–52. http://dx.doi.org/10.1190/tle35040350.1.

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Park, Choon. "MASW for geotechnical site investigation." Leading Edge 32, no. 6 (June 2013): 656–62. http://dx.doi.org/10.1190/tle32060656.1.

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İlkimen, Elif Meriç. "Soil Parameters of Creep Movement Şirinköy-Denizli Example." October 2022 3, no. 4 (December 15, 2022): 1–5. http://dx.doi.org/10.36937/cebel.2022.1767.

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This study, it is aimed to determine how soil parameters affect mass movement. The study area was carried out in the Şirinköy District of Merkezefendi District of Denizli. As a basis for the prevention of mass movements; Geophysical methods are of great importance in terms of determining and monitoring the properties of the sliding forces by determining the ground conditions in the region. For this reason, in this study, the characteristics of the mass movement were determined by determining the soil properties of the study area by using the seismic multi-channel surface wave (MASW) method, which is one of the geophysical methods. With the MASW method, it was determined that the seismic velocities of the area were lower than 910 m/s. The boundaries and units of the geological formations of the ground in the region have been determined. Limestone and fill surface slip surfaces in the area were observed in MASW sections. By evaluating all these studies together, the mass movement in the region was determined as slow flow (creep). Blocky limestone detected in the study area (it is the unit that relatively forms the slip surface. For this reason, developments such as groundwater, growth of roots of plants and trees, wetting, drying and freezing of the ground with the effect of precipitation may cause an acceleration of the movement speed should be followed.

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Ivanov, Julian, Richard D. Miller, Pierre Lacombe, Carole D. Johnson, and John W. Lane. "Delineating a shallow fault zone and dipping bedrock strata using multichannal analysis of surface waves with a land streamer." GEOPHYSICS 71, no. 5 (September 2006): A39—A42. http://dx.doi.org/10.1190/1.2227521.

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The multichannel analysis of surface waves (MASW) seismic method was used to delineate a fault zone and gently dipping sedimentary bedrock at a site overlain by several meters of regolith. Seismic data were collected rapidly and inexpensively using a towed 30-channel land streamer and a rubberband-accelerated weight-drop seismic source. Data processed using the MASW method imaged the subsurface to a depth of about [Formula: see text] and allowed detection of the overburden, gross bedding features, and fault zone. The fault zone was characterized by a lower shear-wave velocity [Formula: see text] than the competent bedrock, consistent with a large-scale fault, secondary fractures, and in-situ weathering. The MASW 2D [Formula: see text] section was further interpreted to identify dipping beds consistent with local geologic mapping. Mapping of shallow-fault zones and dipping sedimentary rock substantially extends the applications of the MASW method.

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Nguyen, Ngan Nhat Kim, Luu Van Do, Van Thanh Nguyen, Trinh Phuc Tran, and Khuong Manh Vo. "Maximizing the energy of surface wave and diminishing the effect of lateral inhomogenousness in the multichannel analysis of the surface wave (MASW)." Science and Technology Development Journal - Natural Sciences 2, no. 5 (July 2, 2019): 105–12. http://dx.doi.org/10.32508/stdjns.v2i5.785.

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Multichannel analysis of surface wave (MASW) is one of the novel seismic methods in geophysic field in Vietnam. MASW is able to survey the stiffness of the soil environment under the ground via the shear-wave velocity VS by analyzing the spectral image of surface wave. We did the 1D MASW survey upon the borehole belonged to the residential development project at district 2, Ho Chi Minh city with fixed receiver system, different source orientations and different source offsets. The spectral images of surface wave were combined to maximize the surface wave’s energy on the spectral image of surface wave to minimize the effect of lateral inhomogenousness and near - far source offsets. The data points were chosen on the phase curve on spectral image of surface wave for the inversion process to define shear wave velocity VS. The VS from MASW was compared to the petrographic components and another seismic method (downhole). The relative difference of the obtained VS values between two methods was less than 10%. The change of VS in MASW was absolutely compatible to petrographic components in geological borehole, near surface filled soil layer (93 m/s), dark-gray silty layer (68–157 m/s), sandy clay layer (250–265 m/s) and lower clay layer (254–400 m/s).

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Samui, Pijush, and T. Sitharam. "Correlation between SPT, CPT and MASW." International Journal of Geotechnical Engineering 4, no. 2 (April 2010): 279–88. http://dx.doi.org/10.3328/ijge.2010.04.02.279-288.

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9

Long, Michael, and Shane Donohue. "In situ shear wave velocity from multichannel analysis of surface waves (MASW) tests at eight Norwegian research sites." Canadian Geotechnical Journal 44, no. 5 (May 1, 2007): 533–44. http://dx.doi.org/10.1139/t07-013.

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The multichannel analysis of surface waves (MASW) technique, which is used to determine shear wave velocity (Vs) and hence small strain stiffness (Gmax), has recently generated considerable interest in the geophysics community. This is because of the ease of carrying out the test and analysis of the data. The objective of this work was to assess the repeatability, accuracy, and reliability of MASW surface wave measurements for use in engineering studies. Tests were carried out at eight well-characterized Norwegian clay, silt, and sand research sites where Vs had already been assessed using independent means. As well as being easy and quick to use, the MASW technique gave consistent and repeatable results, and the MASW Vs profiles for the clay sites were similar to those obtained from other techniques. Reasonable results were also obtained for the silt and sand sites, with the best result being obtained for the finer silt. This work also confirms that MASW Vs clay profiles are comparable to those obtained by correlation with cone penetration test (CPT) data. For these sites there also seems to be a good correlation between normalized small strain shear modulus and in situ void ratio or water content, and the data fit well with published correlations for clays.Key words: soft clays, silts, sands, small strain stiffness, shear wave velocity.

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Ivanov, Julian, Richard D. Miller, Daniel Feigenbaum, Sarah L. C. Morton, Shelby L. Peterie, and Joseph B. Dunbar. "Revisiting levees in southern Texas using Love-wave multichannel analysis of surface waves with the high-resolution linear Radon transform." Interpretation 5, no. 3 (August 31, 2017): T287—T298. http://dx.doi.org/10.1190/int-2016-0044.1.

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Shear-wave velocities were estimated at a levee site by inverting Love waves using the multichannel analysis of surface waves (MASW) method augmented with the high-resolution linear Radon transform (HRLRT). The selected site was one of five levee sites in southern Texas chosen for the evaluation of several seismic data-analysis techniques readily available in 2004. The methods included P- and S-wave refraction tomography, Rayleigh- and Love-wave surface-wave analysis using MASW, and P- and S-wave cross-levee tomography. The results from the 2004 analysis revealed that although the P-wave methods provided reasonable and stable results, the S-wave methods produced surprisingly inconsistent shear-wave velocity [Formula: see text] estimates and trends compared with previous studies and borehole investigations. In addition, the Rayleigh-wave MASW method was nearly useless within the levee due to the sparsity of high frequencies in fundamental-mode surface waves and complexities associated with inverting higher modes. This prevented any reliable [Formula: see text] estimates for the levee core. Recent advances in methodology, such as the HRLRT for obtaining higher resolution dispersion-curve images with the MASW method and the use of Love-wave inversion routines specific to Love waves as part of the MASW method, provided the motivation to extend the 2004 original study by using horizontal-component seismic data for characterizing the geologic properties of levees. Contributions from the above-mentioned techniques were instrumental in obtaining [Formula: see text] estimates from within these levees that were very comparable with the measured borehole samples. A Love-wave approach can be a viable alternative to Rayleigh-wave MASW surveys at sites where complications associated with material or levee geometries inhibit reliable [Formula: see text] results from Rayleigh waves.

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11

Hasya, Cut Atika, Khaizal Khaizal, and Irwandi Irwandi. "Perbandingan Metode Multichannel Analysis of Surface Wave dan Metode Cone Penetration Test Terhadap Analisis Lapisan Tanah." Journal of The Civil Engineering Student 3, no. 1 (April 27, 2021): 14. http://dx.doi.org/10.24815/journalces.v3i1.12265.

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Analisis lapisan tanah yang dilakukan di lapangan salah satunya, metode Cone Penetration Test (CPT) yang menghasilkan parameter utama nilai tahanan ujung konus (qc). Sedangkan, metode Multichannel Analysis of Surface Wave (MASW) adalah metode dari bidang ilmu geofisika untuk menganalisis lapisan tanah yang dapat menghasilkan parameter kecepatan gelombang geser (Vs). Penelitian ini bertujuan untuk mendapatkan parameter gelombang geser (Vs) MASW dan parameter tahanan ujung CPT untuk menganalisis lapisan tanah serta membandingkan hasil dari kedua metode tersebut terhadap karakteristik lapisan tanah sebagai perencanaan pondasi bangunan sipil. Akuisisi data dilakukan di TPI (Tempat Pendaratan Ikan) Lampulo, Kecamatan Kuta Alam. Hasil penelitian pada pengukuran MASW didapatkan nilai Vs sebesar 70 - 130 m/s. Berdasarkan SNI 1726-2012, tanah pada lokasi penelitian termasuk ke dalam kategori Tanah Lunak (SE). Data CPT yang telah dikorelasikan meggunakan persamaan empiris menjadi nilai Vs menunjukkan hasil yang relatif sama dengan klasifikasi tanah pada MASW. Jenis pondasi yang sesuai diterapkan pada lokasi penelitian adalah pondasi tiang karena letak tanah keras berada pada kedalaman lebih dari 10 meter dibawah permukaan tanah.

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Le Ngal, Nwai, Subagyo Pramumijoyo, Iman Satyarno, Kirbani Sri Brotopuspito, Junji Kiyono, and Eddy Hartantyo. "Multi-channel analysis of surface wave method for geotechnical site characterization in Yogyakarta, Indonesia." E3S Web of Conferences 76 (2019): 03006. http://dx.doi.org/10.1051/e3sconf/20197603006.

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On May 27th 2006, Yogyakarta earthquake happened with 6.3 Mw. It was causing widespread destruction and loss of life and property. The average shear wave velocity to 30 m (Vs30) is useful parameter for classifying sites to predict their potential to amplify seismic shaking (Boore, 2004) [1]. Shear wave velocity is one of the most influential factors of the ground motion. The average shear wave velocity for the top 30 m of soil is referred to as Vs30. In this study, the Vs30 values were calculated by using multichannel analysis of surface waves (MASW) method. The Multichannel Analysis of Surface Waves (MASW) method was introduced by Park et al. (1999). Multi-channel Analysis of Surface Waves (MASW) is non-invasive method of estimating the shear-wave velocity profile. It utilizes the dispersive properties of Rayleigh waves for imaging the subsurface layers. MASW surveys can be divided into active and passive surveys. In active MASW method, surface waves can be easily generated by an impulsive source like a hammer, sledge hammer, weight drops, accelerated weight drops and explosive. Seismic measurements were carried out 44 locations in Yogyakarta province, in Indonesia. The dispersion data of the recorded Rayleigh waves were processed by using Seisimager software to obtain shear wave velocity profiles of the studied area. The average shear wave velocities of the soil obtained are ranging from 200 ms-1 to 988 ms-1, respectively.

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Gribler, Gabriel, Lee M. Liberty, and T. Dylan Mikesell. "High-Velocity Surface Layer Effects on Rayleigh Waves: Recommendations for Improved Shear-Wave Velocity Modeling." Bulletin of the Seismological Society of America 110, no. 1 (January 14, 2020): 279–87. http://dx.doi.org/10.1785/0120190120.

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ABSTRACT Soil stiffness estimates are critical to geologic hazard and risk assessment in urban centers. Multichannel analysis of surface-wave (MASW) data collection along city streets is now a standard, cost-effective, and noninvasive soil stiffness approximation tool. With this approach, shear-wave velocities (VS) are derived from Rayleigh-wave signals. Although the current MASW practice is to neglect the effect of a high-velocity road layer on soil VS estimates, our models show measurable impacts on Rayleigh-wave amplitudes and phase velocities when seismic data are acquired on a road surface. Here, we compare synthetic models with field MASW and downhole VS measurements. Our modeling indicates that a road layer attenuates Rayleigh-wave signals across all frequencies, introduces coherent higher-mode signals, and leads to overestimated VS and VS30 values. We show that VS30 can be overestimated by more than 7% when soft soils underlie a rigid road surface. Inaccurate VS estimates can lead to improper soil classification and bias earthquake site-response estimates. For road-based MASW data analysis, we recommend incorporating a surface road layer in the Rayleigh-wave inversion to improve VS estimate accuracy with depth.

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Mi, Binbin, Jianghai Xia, Chao Shen, Limin Wang, Yue Hu, and Feng Cheng. "Horizontal resolution of multichannel analysis of surface waves." GEOPHYSICS 82, no. 3 (May 1, 2017): EN51—EN66. http://dx.doi.org/10.1190/geo2016-0202.1.

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The multichannel analysis of surface wave (MASW) method has been effectively and widely used to determine near-surface shear-wave velocity. Horizontal resolution of the MASW method represents the minimum horizontal length of recognizable geologic anomalous bodies on a pseudo-2D S-wave velocity [Formula: see text] section. Accurately assessing the achievable lateral resolution is one of the main issues in lateral variation reconstruction using the MASW method. It is difficult to quantitatively estimate the horizontal resolution of the MASW method because of the many influencing factors, such as parameters of the observation system, the depth of an anomalous body, and the velocity contrast between the anomalous body and the surrounding rocks. We first analyzed the horizontal resolution of the MASW method based on numerical simulation experiments. According to different influencing factors of the horizontal resolution, we established different laterally heterogeneous models and observation systems and then simulated several synthetic multichannel records with a finite-difference method along a linear survey line using the roll-along acquisition mode. After the extraction of dispersion curves of Rayleigh waves and inversion for S-wave velocity profiles for each synthetic shot gather, a pseudo-2D S-wave velocity section can be generated by aligning the 1D S-wave velocity models. Ultimately, we evaluated the horizontal resolution capability of the MASW method on pseudo-2D [Formula: see text] maps. Our numerical investigation results and field data analysis indicate that [Formula: see text] values on the maps are not the same as the true [Formula: see text] values for structures whose lateral dimension is shorter than a receiver spread length and that anomalous bodies, which are larger and have high velocity contrast, are easier to distinguish on [Formula: see text] maps with a shorter receiver spread length. The horizontal resolution decreases with the increasing depth and is approximately one-half of the shortest Rayleigh wavelength that can penetrate to the depth.

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Karaaslan, Aylin, Argun Kocaoğlu, and Serdar Özalaybey. "Local-scale phase velocity estimation using ambient seismic noise: comparison between passive seismic interferometry and conventional frequency–wavenumber methods." Geophysical Journal International 225, no. 3 (March 1, 2021): 2075–96. http://dx.doi.org/10.1093/gji/ggab080.

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SUMMARY We present a new processing scheme that uses passive seismic interferometry (PSI) followed by multichannel analysis of surface waves (MASW), which we call the 2-D PSI-MASW method, to obtain Rayleigh wave phase velocity dispersion (PVD) information. In this scheme, we first use the principles of PSI to form multidirectional cross-correlations (CCs) then project the CCs onto a 1-D virtual array and apply the phase-shift transform as in MASW processing. We compare PVD information obtained by this method with those of the conventional beam-power based frequency–wavenumber decomposition (CVFK) method using ambient seismic noise (ASN) data collected by local-scale 2-D arrays deployed at three selected sites in Bursa, Turkey. By analysing the ASN data from these sites, we show that similar multimodal PVD curves can be obtained with the two methods over a broad frequency range (∼2–23 Hz) within the wavenumber resolution and aliasing limits. However, in one of our sites where the 2-D array configuration has a considerable antisymmetry, we show that the 1-D virtual array used in the 2-D PSI-MASW method has a better array response function in terms of wavenumber resolution and suppression of side-lobes leading to superior mode resolution and separation than that of the CVFK method, which shows strong directional variations. Furthermore, unlike the CVFK method, the 2-D PSI-MASW method takes advantage of temporal stacking of CCs ensuring weak but coherent Rayleigh wave signals present in the ASN wavefield to be strengthened and has the potential for better extraction of PVD information. We conclude that by using a 2-D array with spatial coverage providing a wide range of directions and distances, reliable PVD information can be obtained even if the ASN sources are not concentrated in the stationary phase zones. Thus, we suggest that the 2-D PSI-MASW method is highly advantageous for the extraction of reliable PVD information owing to the multidirectional CCs provided by the 2-D array configurations. We also report that using only a single receiver line in the interferometric approach results in biased and/or incomplete PVD information due to the non-isotropic ASN source distribution at all three sites we analysed. In conclusion, our results clearly indicate that the 2-D PSI-MASW method can be used as complementary or alternative to the CVFK method to extract multimodal Rayleigh wave PVD information in local-scale seismological studies.

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Crice, D. "MASW, The Wave of the Future Editorial." Journal of Environmental & Engineering Geophysics 10, no. 2 (June 1, 2005): 77–79. http://dx.doi.org/10.2113/jeeg10.2.77.

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Suto, Koya. "MASW surveys in landfill sites in Australia." Leading Edge 32, no. 6 (June 2013): 674–78. http://dx.doi.org/10.1190/tle32060674.1.

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Park, Choon, Jason Richter, Roger Rodrigues, and Alessandro Cirone. "MASW applications for road construction and maintenance." Leading Edge 37, no. 10 (October 2018): 724–30. http://dx.doi.org/10.1190/tle37100724.1.

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Olafsdottir, Elin Asta, Bjarni Bessason, and Sigurdur Erlingsson. "Combination of dispersion curves from MASW measurements." Soil Dynamics and Earthquake Engineering 113 (October 2018): 473–87. http://dx.doi.org/10.1016/j.soildyn.2018.05.025.

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Ayolabi, E. A., and R. B. Adegbola. "Application of MASW in road failure investigation." Arabian Journal of Geosciences 7, no. 10 (October 8, 2013): 4335–41. http://dx.doi.org/10.1007/s12517-013-1078-z.

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McBride, John H., Stephen T. Nelson, Choon B. Park, Eugene E. Wolfe, David G. Tingey, and Kevin A. Rey. "Ocean waves as a passive MASW source." Journal of Applied Geophysics 171 (December 2019): 103860. http://dx.doi.org/10.1016/j.jappgeo.2019.103860.

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Khan, Zahid, and Mohammad Yamin. "Evaluation of shear geophones in MASW testing." International Journal of Geotechnical Engineering 13, no. 2 (May 19, 2017): 184–90. http://dx.doi.org/10.1080/19386362.2017.1329260.

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Paz, Maria, Francisco Alcalá, Ana Medeiros, Pedro Martínez-Pagán, Jaruselsky Pérez-Cuevas, and Luís Ribeiro. "Integrated MASW and ERT Imaging for Geological Definition of an Unconfined Alluvial Aquifer Sustaining a Coastal Groundwater-Dependent Ecosystem in Southwest Portugal." Applied Sciences 10, no. 17 (August 26, 2020): 5905. http://dx.doi.org/10.3390/app10175905.

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This paper integrates multichannel analysis of surface waves (MASW) and time-lapse electrical resistivity tomography (ERT) to define aquifer geometry and identify transient groundwater features of the Cascalheira Stream Basin Holocene alluvial aquifer (aquifer H), which contributes to the Santo André Lagoon, part of a coastal groundwater-dependent ecosystem (GDE), located in southwest Portugal. MASW measures shear-wave velocity (VS), allowing one to obtain steady geological models of the subsurface, and ERT measures subsurface electrical resistivity (ER), being subjected to ambient changes. MASW enables disambiguation of geological structures in low ER environments, such as coastal areas. This research covered one natural year and involved one MASW campaign, four ERT campaigns, and additional geological field surveys and groundwater monitoring to assist interpretation of results. In the area, the conjugate NW–SE and NE–SW strike-slip fault systems determine compartmentalization of geological structures and subsequent accommodation space for Holocene sedimentation. MASW and ERT surveys show how the NW–SE system deepens these structures toward the coast, whereas the NE–SW system generates small horsts and grabens, being one of these occupied by aquifer H. From upstream to downstream, aquifer H thickness and width increase from 10 m to 12 m and from 140 m to 240 m, respectively. Performance of VS and ER models was satisfactory, with a normalized error of the VR and ER models in the 0.01–0.09 range, meaning that a quantitative quota of uncertainty can be segregated from the overall uncertainty of groundwater models without substantially affecting its simulations accuracy. This methodology seeks to improve the design of shallow groundwater research in GDE preservation policies.

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Chen, Hongbing, Bin Xu, Jiang Wang, Lele Luan, Tianmin Zhou, Xin Nie, and Yi-Lung Mo. "Interfacial Debonding Detection for Rectangular CFST Using the MASW Method and Its Physical Mechanism Analysis at the Meso-Level." Sensors 19, no. 12 (June 20, 2019): 2778. http://dx.doi.org/10.3390/s19122778.

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In this study, the transient multichannel analysis of surface waves (MASW) is proposed to detect the existence, the location and the length of interface debonding defects in rectangular concrete-filled steel tubes (CFST). Mesoscale numerical analysis is performed to validate the feasibility of MASW-based interfacial debonding detection. Research findings indicate that the coaxial characteristics in the Rayleigh wave disperse at the starting point of the debonding area and gradually restores at the end of the defect. For healthy specimens, the surface wave mode in CFST is closer to the Rayleigh wave. However, it can be treated as a Lamb wave since the steel plate is boundary-free on both sides in the debonding area. The displacement curves are further investigated with forward analysis to obtain the dispersion curves. The mesoscale numerical simulation results indicate that the propagation characteristic of the surface wave is dominated by the debonding defect. The detectability of interfacial debonding detection for rectangular CFST using the MASW approach is numerically verified in this study. The proposed MASW-based nondestructive testing technique can achieve bond-slip detection by comparing the variation trend of the coaxial characteristics in the time-history output signals and the dispersion curves obtained from the forward analysis, for avoiding misjudgment of the experimental observations.

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HUSSAIN, Yawar, Hernan MARTINEZ-CARVAJAL, Martín CÁRDENAS-SOTO, and Rogério Elias Soares UAGODA. "ANALYSIS OF SURFACE WAVES RECORDED AT A MASS MOVEMENT IN BRASÍLIA, BRAZIL: AN IMPLICATION IN HAZARD MITIGATION." Geosciences = Geociências 37, no. 2 (June 25, 2018): 385–91. http://dx.doi.org/10.5016/geociencias.v37i2.12539.

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Ever increasing urbanization over the thick and less cohesive soil of the Federal District (DF), Brazil has increased area's vulnerability to natural hazards, especially the soil erosion and mass movement. This preliminarily study applied noise based geophysical techniques like power spectral density (PSD), horizontal to vertical spectral ratio (HVSR), multichannel analysis of surface waves (MASW) and noise interferometry to a mass movement in Brasilia for the understating of geodynamic processes working in the background of these hazards. Here obtained results show a uniform stratigraphic peak at 2 Hz observed on all HVSR curves, a four layered shear wave section was obtained by MASW. Dispersion curve (frequency vs phase velocity) shows first and second fundamental modes at frequencies of 5 and 25 Hz, respectively. Noise correlograms show time delay larger than +- 0.5 sec on the waveforms of ZR (vertical-radial) component, mainly in acausal part. Relative velocity changes calculated by stretching technique show anomalous trends in response to rainfall events. Follow research will focus on the detection of possible changes in noise records within mass movement mainly related to natural triggering factors (rainfall and river erosion) under more controlled data conditions.

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Coe, Joseph T., and Siavash Mahvelati. "Full Waveform Tomography to Address Challenges with Surface Wave Dispersion Information Caused by Significant Stochastic Variability of Subsurface Stiffness." Journal of Environmental and Engineering Geophysics 26, no. 4 (December 2021): 267–78. http://dx.doi.org/10.32389/jeeg21-013.

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Surface wave methods have increased in popularity as a means to acquire rapid and accurate shear wave velocity ( VS) profiles for engineering applications. Use of the multichannel analysis of surface waves (MASW) method, in particular, has proliferated due to multiple factors, including the ease with which strong signal-to-noise ratio can be achieved and the increased dispersion resolution offered by multichannel acquisitions. However, typical MASW processing to extract dispersion information assumes the surface waves propagate through a layered model. Errors can arise when significant lateral variability is present in the underlying stratigraphy as encountered in certain geologic settings such as residual deposits. This study investigated the effects of such variability on the dispersion information acquired with MASW. In particular, a spatially-correlated Gaussian random field was used to model the natural fluctuations in stiffness introduced by depositional processes, which differs from the approach in other studies where more specific anomalous features have been explored. Numerical modeling was subsequently performed to simulate surface wave propagation in the representative geotechnical site condition. The recovered surface waves were used to develop a subsurface stiffness profile using a dispersion-based pseudo-2D MASW approach and a tomographic approach using full waveform inversion (FWI). The results demonstrate that considerable natural spatial variability significantly complicates interpretation of dispersion information in two primary ways: (1) uncertainty can arise regarding what the dispersion curve exactly quantifies since none of the underlying VS profiles nor the average VS profile are obtained; and (2) the dispersion images exhibit evidence of false depth-related dispersion information indicative of multiple “fundamental” modes from the superposition of multiple stratigraphic units. The FWI procedure that bypasses extraction of dispersion information was found to better recover the underlying subsurface conditions when compared to the pseudo-2D MASW results at the cost of additional computational efforts.

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Neducza, Boriszláv. "Stacking of surface waves." GEOPHYSICS 72, no. 2 (March 2007): V51—V58. http://dx.doi.org/10.1190/1.2431635.

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The seismic surface wave method (SWM) is a powerful means of characterizing near-surface structures. Although the SWM consists of only three steps (data acquisition, determination of dispersion curves, and inversion), it is important to take considerable care with the second step, determination of the dispersion curves. This step is usually completed by spectral analysis of surface waves (SASW) or multichannel analysis of surface waves (MASW). However, neither method is ideal, as each has its advantages and disadvantages. SASW provides higher horizontal resolution, but it is very sensitive to coherent noise and individual geophone coupling. MASW is a robust method able to separate different wave types, but its horizontal resolution is lower. Stacking of surface waves (SSW) is a good compromise between SASW and MASW. Using a reduced number of traces increases the horizontal resolution of MASW, and utilizing other shot records with the same receivers compensates for the decreased signal-to-noise ratio. The stacking is realized by summing the [Formula: see text] amplitude spectra of windowed shot records, where windowing produces higher horizontal resolution and stacking produces improved data quality. Mixing is applied between the stacks derived with different parameters, as different frequency ranges require different windowing. SSW was tested and corroborated on a deep seismic data set. Horizontal resolution is validated by [Formula: see text] plots at different frequencies, and [Formula: see text] plots present data quality.

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Cheng, Feng, Jianghai Xia, Yinhe Luo, Zongbo Xu, Limin Wang, Chao Shen, Ruofei Liu, Yudi Pan, Binbin Mi, and Yue Hu. "Multichannel analysis of passive surface waves based on crosscorrelations." GEOPHYSICS 81, no. 5 (September 2016): EN57—EN66. http://dx.doi.org/10.1190/geo2015-0505.1.

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Passive seismic methods in highly populated urban areas have gained much attention from geophysics and civil engineering communities because traditional seismic surveys, especially in complex urbanized environments, might be improperly applied. In passive seismic methods, directional noise sources will inevitably bring azimuthal effects and spatial aliasing to dispersion measurements due to the fact that true randomness of ambient noise cannot be achieved in reality. To solve these problems, multichannel analysis of passive surface (MAPS) waves based on long noise sequence crosscorrelations is proposed. We have introduced a hybrid method of seismic interferometry and the roadside passive multichannel analysis of surface waves (MASW) using crosscorrelation to produce common virtual source gathers from 1 h multichannel noise records. Common virtual source gathers are then used to do dispersion analysis with an active scheme based on phase-shift measurement. Synthetic tests demonstrated the advantages of this method with azimuthal adjustment and dispersion imaging for directional noise source distribution. Two field applications were conducted, and results from the roadside passive MASW, MAPS, and spatial autocorrelation method were compared. Our study indicated the superiority of MAPS over the roadside passive MASW on the validity of azimuth detection, feasibility of combining the active MASW and MAPS, and accuracy in determining dispersion energy trends, especially at a relative low-frequency range ([Formula: see text]) in urban areas.

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Olafsdottir, Elin Asta, Sigurdur Erlingsson, and Bjarni Bessason. "Open-Source MASW Inversion Tool Aimed at Shear Wave Velocity Profiling for Soil Site Explorations." Geosciences 10, no. 8 (August 17, 2020): 322. http://dx.doi.org/10.3390/geosciences10080322.

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The shear wave velocity profile is of primary interest for geological characterization of soil sites and elucidation of near-surface structures. Multichannel Analysis of Surface Waves (MASW) is a seismic exploration method for determination of near-surface shear wave velocity profiles by analyzing Rayleigh wave propagation over a wide range of wavelengths. The inverse problem faced during the application of MASW involves finding one or more layered soil models whose theoretical dispersion curves match the observed dispersion characteristics. A set of open-source MATLAB-based tools for acquiring and analyzing MASW field data, MASWaves, has been under development in recent years. In this paper, a new tool, using an efficient Monte Carlo search technique, is introduced to conduct the inversion analysis in order to provide the shear wave velocity profile. The performance and applicability of the inversion scheme is demonstrated with synthetic datasets and field data acquired at a well-characterized geotechnical research site.

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Adegbola, R. B., K. F. Oyedele, L. Adeoti, and A. B. Adeloye. "Multichannel analysis of the surface waves of earth materials in some parts of Lagos State, Nigeria." Materials and Geoenvironment 63, no. 2 (September 1, 2016): 81–90. http://dx.doi.org/10.1515/rmzmag-2016-0007.

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Abstract We present a method that utilizes multichannel analysis of surface waves (MASW), which was used to measure shear wave velocities, with a view to establishing the probable causes of road failure, subsidence and weakening of structures in some local government areas in Lagos, Nigeria. MASW data were acquired using a 24-channel seismograph. The acquired data were processed and transformed into a two-dimensional (2-D) structure reflective of the depth and surface wave velocity distribution within a depth of 0–15 m beneath the surface using SURFSEIS software. The shear wave velocity data were compared with other geophysical/ borehole data that were acquired along the same profile. The comparison and correlation illustrate the accuracy and consistency of MASW-derived shear wave velocity profiles. Rigidity modulus and N-value were also generated. The study showed that the low velocity/ very low velocity data are reflective of organic clay/ peat materials and thus likely responsible for the failure, subsidence and weakening of structures within the study areas.

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Yadav, Shubhamjeet, Madan Chandra Maurya, and Keshav Kumar Sharma. "Seismic Site Response Analysis of MMMUT Gorakhpur of Uttar Pradesh, India." IOP Conference Series: Materials Science and Engineering 1273, no. 1 (January 1, 2023): 012005. http://dx.doi.org/10.1088/1757-899x/1273/1/012005.

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Abstract An endeavour has been made to assess the spatial fluctuation of the profundity of endured and designing bedrock in Gorakhpur Uttar Pradesh, North India utilizing Multichannel Analysis of Surface Wave (MASW) study. One-layered MASW study has been done at Madan Mohan Malaviya University of Technology, Gorakhpur campus and Shear-wave Velocity V S 30 are estimated. MASW overview at 3 location and a Standard Penetration Test SPT-N from the profound geotechnical boreholes data used for comparison of site classification. The deduction of this work might be utilized as contributions for seismic tremor risk the board by lessening the seriousness of earthquake shaking through plan of tremor Earthquake risk resilient structure strong designs. The data that collected from the MASW experimental setup is feed using the software ParkSEIS (v.3.0), we obtain Shear Wave Velocity (VS30 ). The obtained V S 30 is used to plot Response Spectra for MMMUT Gorakhpur. The Time History data used in this thesis is Nepal Earthquake 2015 data which is collected from Indian Metrological Department (IMD) Delhi, India. SPT-N value data is collected from Awas Vikas Parishad for the New Administration Building build at MMMUT campus Gorakhpur. The Time History data of Nepal Earthquake 2015 is analysed using DEEPSOIL v7 Software and a systematic layer wise study of MMMUT Campus soil is carried out, results such as Ground Motion Parameters, Response Spectra, Spectral acceleration vs Frequency plot, Tripartite Spectrum and Response spectra corresponding to 5% damping are obtained.

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Park, C. B., and R. D. Miller. "Roadside Passive Multichannel Analysis of Surface Waves (MASW)." Journal of Environmental & Engineering Geophysics 13, no. 1 (March 1, 2008): 1–11. http://dx.doi.org/10.2113/jeeg13.1.1.

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Steinel, Hannes, Jörg Hausmann, Ulrike Werban, and Peter Dietrich. "Reliability of MASW profiling in near‐surface applications." Near Surface Geophysics 12, no. 6 (June 2014): 731–37. http://dx.doi.org/10.3997/1873-0604.2014029.

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Almalki, Hashim, and Khyzer Munir. "Efficiency of MASW in detecting near-surface cavities." ASEG Extended Abstracts 2013, no. 1 (December 2013): 1–4. http://dx.doi.org/10.1071/aseg2013ab043.

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Zainorabidin, A., and M. J. M. Said. "Dynamic Characteristics of Penor Peat Using MASW Method." IOP Conference Series: Materials Science and Engineering 136 (July 2016): 012024. http://dx.doi.org/10.1088/1757-899x/136/1/012024.

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Mihai, Marinescu, Cristea Paul, Marunteanu Cristian, and Mezincescu Matei. "MASW Seismic Method in Brebu Landslide Area, Romania." IOP Conference Series: Earth and Environmental Science 95 (December 2017): 032035. http://dx.doi.org/10.1088/1755-1315/95/3/032035.

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Suto, Koya. "An Unbiased Spiral Array for MASW Data Acquisition." First Break 41, no. 8 (August 1, 2023): 89–94. http://dx.doi.org/10.3997/1365-2397.fb2023067.

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Olafsdottir, Elin Asta, Sigurdur Erlingsson, and Bjarni Bessason. "Tool for analysis of multichannel analysis of surface waves (MASW) field data and evaluation of shear wave velocity profiles of soils." Canadian Geotechnical Journal 55, no. 2 (February 2018): 217–33. http://dx.doi.org/10.1139/cgj-2016-0302.

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Multichannel analysis of surface waves (MASW) is a fast, low-cost, and environmentally friendly technique to estimate shear wave velocity profiles of soil sites. This paper introduces a new open-source software, MASWaves, for processing and analysing multichannel surface wave records using the MASW method. The software consists of two main parts: a dispersion analysis tool (MASWaves Dispersion) and an inversion analysis tool (MASWaves Inversion). The performance of the dispersion analysis tool is validated by comparison with results obtained by the Geopsy software package. Verification of the inversion analysis tool is carried out by comparison with results obtained by the software WinSASW and theoretical dispersion curves presented in the literature. Results of MASW field tests conducted at three sites in south Iceland are presented to demonstrate the performance and robustness of the new software. The soils at the three test sites ranged from loose sand to cemented silty sand. In addition, at one site, the results of existing spectral analysis of surface waves (SASW) measurements were compared with the results obtained by MASWaves.

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Kumar, Jyant, and Tarun Naskar. "Resolving phase wrapping by using sliding transform for generation of dispersion curves." GEOPHYSICS 82, no. 3 (May 1, 2017): V127—V136. http://dx.doi.org/10.1190/geo2016-0207.1.

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The complexity involved with the phase unwrapping procedure, while performing the existing spectral analysis of surface waves (SASW) on the basis of two sensors, makes it difficult to automate and requires frequent manual judgment. As a result, this approach generally becomes tedious and may yield erroneous results. The multichannel analysis of surface waves (MASW) technique can resolve the problem of phase wrapping. However, the MASW technique normally requires a large number of closely spaced sensors, typically 24–48 or even more. We have developed a new method that is fast, accurate, and generally resolves the unwrapping of phase with the use of just two sensors, provided the signal-to-noise ratio remains high. In this approach, the unwrapping of the phase can be performed without any manual intervention and an automation of the process becomes feasible. A few examples, involving synthetic test data and surface-wave tests, have been tested to determine the efficacy of our approach. Comparisons of the results have been made with the corresponding solutions using existing SASW and MASW techniques.

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El-Raouf, Amr Abd, Ibrar Iqbal, Julia Meister, Kamal Abdelrahman, Hassan Alzahrani, and Osman M. Badran. "Earthflow reactivation assessment by multichannel analysis of surface waves and electrical resistivity tomography: A case study." Open Geosciences 13, no. 1 (January 1, 2021): 1328–44. http://dx.doi.org/10.1515/geo-2020-0310.

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Abstract In this study, we investigated the stability and reactivation of preexisting Tonghua landslide deposits in China, including the adjacent stable slope. We used an integrated approach, combining a multichannel analysis of surface waves (MASW) and electrical resistivity tomography (ERT). We used ERT to determine groundwater seepage paths, weathering conditions, water content, and the depth to bedrock. High-resolution two-dimensional (2D) shear-wave velocity MASW images, on the other hand, played an essential role in detecting both horizontal and vertical compositions, disjointedness, and sliding surfaces related to lithological borders. Based on seismic models, we considered four geological layers encountered in the stable slope, including fractured (gravel) and weathered (phyllite) materials, as a sliding mass. We combined the 2D resistivity profiles obtained to create pseudo-three-dimensional ERT images to estimate water-saturated and unsaturated masses. From the tomography results, we identified different preexisting deposits, including buried arable clay deposits, old accumulated earthflow deposits, a water accumulation zone, and a fissure runoff. Based on the resistivity results, the bottom of the earthflow deposits is susceptible to water, and oversaturation can reactivate the earthflow.

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Eikmeier, Claus Naves, Renato Luiz Prado, and Fabio Taioli. "COMBINED USE OF ACTIVE AND PASSIVE SURFACE WAVES FOR SHALLOW SUBSURFACE INVESTIGATION IN NOISY URBAN AREA OF SÃO PAULO CITY, BRAZIL." Revista Brasileira de Geofísica 34, no. 1 (February 7, 2016): 13. http://dx.doi.org/10.22564/rbgf.v34i1.648.

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ABSTRACT. The dynamic shear modulus (Gdin) is important for geotechnical engineering, particularly for calculating the dynamic response of foundations. Gdin is determined from material densities and S-wave propagation velocity (VS). Usually, crosshole test is used for such determination. However, it is an expensive and invasive technique because it is based on drilling. The MASW method (Multichannel Analysis of Surface Waves) becomes an interesting option for being faster, more economical and easier to carry out. This paper presents results obtained with MASW method in a densely built up area with high traffic noise level in São Paulo city, Brazil. Results are compared with those obtained by crosshole test as well as geotechnical sounding data. The influence of some acquisition parameters was evaluated in data quality and final inversion result. Besides, it was also tested the passive mode test that is recording ambient noise. Best results were obtained by joint inversion of fundamental and higher curve modes extracted from stacked images generated from data acquired employing sledgehammer and passive sources. Final VS models were coherent with results obtained from crosshole seismic testing and mechanical sounding description, demonstrating MASWmethod can generate important information for geological and geotechnical investigation of urban areas. Keywords: MASW, seismic, Rayleigh wave, velocity profile, dispersion curve.RESUMO. O módulo de cisalhamento dinâmico (Gdin) é importante para a engenharia geotécnica, particularmente nos cálculos de fundações sujeitas a esforços dinâmicos. O Gdin é determinado a partir das densidades dos materiais e das velocidades de propagação das ondas S (VS). Normalmente se utiliza o ensaio crosshole, ensaio sísmico entre poços, para tal determinação, porém, trata-se de uma aquisição de execução dispendiosa. Este trabalho apresenta resultados obtidos com o método MASW em uma área densamente edificada e com alto nível de ruído de tráfego na cidade de São Paulo, Brasil, que são comparados com os obtidos por ensaio crosshole, assim como com dados de sondagem direta. Avaliou-se, também, a influência de alguns parâmetros de aquisição na qualidade do dado e no resultado final da inversão. Testou-se ainda a aquisição de dados no modo passivo, ou seja, registrando-se o ruído ambiental. Os melhores resultados foram obtidos utilizando-se inversão conjunta dos modos fundamental e superiores das curvas extraídas do empilhamento das imagens de dispersão dos dados gerados com as fontes marreta e passiva. Os modelos de VS obtidos foram coerentes com os resultados obtidos do ensaio sísmico crosshole e da descrição da sondagem mecânica, demonstrando que o método MASW pode gerar importantes informações para investigações geológicas e geotécnicas de áreas urbanas. Palavras-chave: MASW, sísmica, onda Rayleigh, perfil de velocidades, curva de dispersão.

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Tokeshi, K., P. Harutoonian, C. J. Leo, and S. Liyanapathirana. "Use of surface waves for geotechnical engineering applications in Western Sydney." Advances in Geosciences 35 (June 27, 2013): 37–44. http://dx.doi.org/10.5194/adgeo-35-37-2013.

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Abstract. Current in situ methods used to geotechnically characterize the ground are predominantly based on invasive mechanical techniques (e.g. CPT, SPT, DMT). These techniques are localized to the tested area thus making it quite time consuming and costly to extensively cover large areas. Hence, a study has been initiated to investigate the use of the non-invasive Multichannel Analysis of Surface Waves (MASW) and Multichannel Simulation with One Receiver (MSOR) techniques to provide both an evaluation of compacted ground and a general geotechnical site characterization. The MASW technique relies on the measurement of active ambient vibrations generated by sledgehammer hits to the ground. Generated vibrations are gathered by interconnected electromagnetic geophones set up in the vertical direction and in a linear array at the ground surface with a constant spacing. The MSOR technique relies on one sensor, one single geophone used as the trigger, and multiple impacts are delivered on a steel plate at several distances in a linear array. The main attributes of these non-invasive techniques are the cost effectiveness and time efficiency when compared to current in situ mechanical invasive methods. They were applied to infer the stiffness of the ground layers by inversion of the phase velocity dispersion curves to derive the shear wave velocity (Vs) profile. The results produced by the MASW and the MSOR techniques were verified against independent mechanical Cone Penetration Test (CPT) and Standard Penetration Test (SPT) data. This paper identifies that the MASW and the MSOR techniques could be potentially useful and powerful tools in the evaluation of the ground compaction and general geotechnical site characterization.

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Lu, Zhiqu. "An acoustic near surface soil profiler using surface wave method." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A58. http://dx.doi.org/10.1121/10.0010649.

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An acoustic soil profiler, using a so-called the high-frequency multi-channel analysis of surface waves (HF-MASW) method, has been developed, which uses surface (Rayleigh) waves to measure soil profile in terms of the shear (S) wave velocity as a function of depth, up to a 2.5 m deep below the surface. Several practical techniques have been developed to enhance the HF-MASW method, including (1) a variable sensor spacing configuration, (2) the self-adaptive method, and (3) the phase-only signal processing. Fundamentally, the S-wave velocity is related to soil mechanical and hydrological properties through the principle of effective stress. Therefore, the measured two-dimensional S-wave velocity images reflect the temporal and spatial variations of soils due to weather effects, geological anomalies, and anthropologic activities. Several HF-MASW applications will be reported, including (1) near surface soil profiling, (2) a long-term-survey for studying weather and seasonal effects, (3) short-term monitoring rain fall events, (4) detecting fraigpan layers, and (5) a farmland compaction study. This acoustic soil profiler can be used for agricultural, environmental, civil engineering, and military applications.

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Luo, Kun. "The Application of MASW Method on the Studying of the Vibrations in Civil Engineering." Advanced Materials Research 989-994 (July 2014): 958–60. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.958.

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Surface-wave dispersion analysis is widely used in civil engineering to infer a shear wave velocity model of the subsoil for a wide variety of applications. Combining with a example, multi-channel analysis of surface waves method (MASW) was discussed in this paper. The entire MASW's procedure of three steps: acquiring ground roll data in the field, processing the data to determine dispersion curve, and back calculation of the geologic parameters for different depths. Based upon all the research results by far, MASW method is an efficient methods because of its high accuracy that is achieved by both special field technique and data processing technique.

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RUAN, SHI-SEN, JIANG-HONG MAN, SHAN WU, and ZE CHENG. "Nonlinear magnetoacoustic waves in pair-ion plasma with dust impurity." Journal of Plasma Physics 79, no. 5 (May 29, 2013): 825–31. http://dx.doi.org/10.1017/s0022377813000573.

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AbstractNonlinear properties of magnetoacoustic waves are investigated in magnetized pair-ion plasmas with dust impurity. Three-fluid collisionless magneto-hydrodynamic model is considered and reductive perturbation method is employed to derive Korteweg-de Vries equation for magnetoacoustic solitary waves (MASWs). The effects of the charge number of dust particles, magnetic field intensity, and plasma number density are studied on MASWs. It is found that the variation of parameters causes significant changes in solitary structures. The present investigation may be useful to understand formation and propagation of MASW structures in dust pair-ion plasmas.

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Efremov, R. A., A. S. Serdyukov, and A. V. Yablokov. "Determination of the contrast boundaries of the low velocity zone by analyzing the features of the dispersion curves of the Rayleigh wave velocities based on empirical dependencies." Russian Journal of Geophysical Technologies, no. 2 (September 1, 2023): 16–28. http://dx.doi.org/10.18303/2619-1563-2023-2-16.

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An important application of the multichannel surface wave (MASW) method is seismic safety assessment. The key parameters in the calculation of increments in the input of seismic microzoning are the thickness and average velocity of the soil mass lying on the base of more rigid rocks. To determine these parameters, we propose a new method for constructing horizontally layered models of the upper part of the geological section using the features (positions of extrema of the second derivative) of the dispersion curves of phase velocities of the Rayleigh surface wave, which, as shown by numerical experiments, are associated with the position of contrasting boundaries in the medium under study. (e.g., the boundary between soils and rocks). This approach is much simpler than the problem of recovering a horizontally layered model traditionally solved in the MASW method from a set of phase velocities for a sequence of frequencies and does not require an initial approximation and/or any restrictions on the possible values of the model parameters. In the case of two-layer and three-layer media, our approach is reduced to a simple and fast application of explicit formulas.

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Guireli Netto, Leonides, Otavio Coaracy Brasil Gandolfo, Walter Malagutti Filho, and João Carlos Dourado. "NON-DESTRUCTIVE INVESTIGATION ON SMALL EARTH DAMS USING GEOPHYSICAL METHODS: SEISMIC SURFACE WAVE MULTICHANNEL ANALYSIS (MASW) AND S-WAVE REFRACTION SEISMIC METHODS." Brazilian Journal of Geophysics 38, no. 1 (March 4, 2020): 5. http://dx.doi.org/10.22564/rbgf.v38i1.2031.

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ABSTRACT. The application of non-destructive methods of investigation in dams, such as refractive seismic method and Multichannel Analysis of Surface Waves (MASW) are increasingly effective from the point of choosing the best dam site, as well as in the phases of construction and maintenance of the structure. The objective of the research was to apply geophysical methods in the structure of the dam to detect the internal flow of fluids, the presence of voids, find possible fracture zones and variations in the level of saturation of the massif, characteristics related to permeability and directly linked to the stability of the dam. In this way, geophysical methods have proved to be excellent tools, because, unlike instrumentation traditionally used in this type of monitoring, such as piezometers and water level indicators, they can cover a large study area quickly. This paper aims to present the results of the correlation between the MASW method and the S-wave seismic refraction method in two small earth dams in the countryside of the State of São Paulo, Brazil, more precisely in the cities of Cordeirópolis and Ipeúna. The main goal was to obtain the depths of the rocky top and the saturated/unsaturated zone of the earth dams using seismic tests under conditions of lack of information about the construction of the dam. The application of geophysical methods in dams that do not previously have important information (presence of drainage blanket, vertical/horizontal filters, for example) proves to be a very interesting non-destructive investigation technique.Keywords: geophysics in dams, MASW, seismic refraction, dam investigation. INVESTIGAÇÃO NÃO-DESTRUTIVA EM BARRAGENS DE TERRA DE PEQUENO PORTE USANDO MÉTODOS GEOFÍSICOS: ANÁLISE MULTICANAL DE ONDAS SUPERFICIAIS (MASW) E SÍSMICA DE REFRAÇÃO TOMOGRÁFICARESUMO. A aplicação de métodos não destrutivos de investigação em barragens, como o método da sísmica de refração e a análise multicanal de ondas de superfície (MASW), são cada vez mais eficazes desde a fase de escolha do melhor local para a instalação da barragem, bem como nas fases da construção e manutenção da estrutura. O objetivo da pesquisa foi aplicar métodos geofísicos na estrutura da barragem para detectar o fluxo interno de fluidos, a presença de vazios, encontrar possíveis zonas de fratura e variações no nível de saturação do maciço, características relacionadas à permeabilidade e diretamente ligadas à estabilidade da barragem. Desta forma, os métodos geofísicos se mostraram como excelentes ferramentas, pois puderam cobrir uma grande área de estudo com rapidez, diferentemente da tradicional instrumentação utilizada neste tipo de monitoramento, como piezômetros e indicadores do nível d'água. Este trabalho tem como objetivo apresentar os resultados da correlação entre o método MASW e o método sísmico de refração com ondas S em duas pequenas barragens de terra no interior do Estado de São Paulo, mais precisamente nas cidades de Cordeirópolis e Ipeúna. O objetivo principal foi o de obter as profundidades do topo rochoso e da zona saturada/insaturada das barragens de terra fazendo uso de ensaios sísmicos em condições de ausência de informações a respeito da construção do barramento. A aplicação de métodos geofísicos em barragens que não possuem previamente informações importantes (presença de tapete drenante, filtros verticais/horizontais, por exemplo) mostra-se como uma técnica de investigação não destrutiva bastante interessante.Palavras-chave: geofísica em barragens, MASW, sísmica de refração, investigação em barragens.

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Rahimi, Salman, Timothy Moody, Clinton Wood, Behdad Mofarraj Kouchaki, Michelle Barry, Khiem Tran, and Chris King. "Mapping Subsurface Conditions and Detecting Seepage Channels for an Embankment Dam Using Geophysical Methods: A Case Study of the Kinion Lake Dam." Journal of Environmental and Engineering Geophysics 24, no. 3 (September 2019): 373–86. http://dx.doi.org/10.2113/jeeg24.3.373.

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Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography (ERT), and seismic surface wave testing using Love and Rayleigh waves were performed on Kinion Lake Dam, an embankment dam that has historically experienced significant seepage and internal erosion issues. The goal of this study is to detect seepage locations in the embankment dam for remediation purposes and map bedrock location across the area using nondestructive geophysical measurements. Surveys were completed along the crest and downstream toe of the dam to map subsurface conditions with a focus on seepage detection. The seismic surface wave data were analyzed using two different methods: Multichannel Analysis of Surface Waves (MASW) and Full Waveform Inversion (FWI). Both MASW and FWI methods were shown to be capable of resolving the bedrock layer below the dam, but the FWI method, provided a higher resolution image of the subsurface conditions compared to MASW method. However, the MASW and FWI provided little guidance regarding the seepage path through the dam. The CCR and ERT surveys, on the other hand, were shown to be very valuable for seepage detection. The seepage paths of the embankment dam were detected by comparing the resistivity measurements acquired in a wet winter and a dry summer. These seepage regions correspond well with previous sinkholes observed in the pool area following a drought. Additionally, new drilling in the two regions which showed differences in resistivity indicated the areas contained highly fractured limestone with evidence of solution cavities. It seems that the highly fractured limestone becomes fully saturated during the wet season causing very low resistivity values for these layers in wet seasons, but it quickly loses the water during the dry season leading to a highly resistive material in dry seasons. Therefore, seasonal resistivity measurements can be considered as a useful method for locating potential weak zones of earthen hydraulic structures in a cost-effective and timely manner.

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Jafri, Nur Jihan Syamimi, Mohd Asri Ab Rahim, Mohd Zulham Affandi Mohd Zahid, Nor Faizah Bawadi, Muhammad Munsif Ahmad, Ahmad Faizal Mansor, and Wan Mohd Sabki Wan Omar. "Assessment of soil compaction properties based on surface wave techniques." E3S Web of Conferences 34 (2018): 01002. http://dx.doi.org/10.1051/e3sconf/20183401002.

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Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

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Baglari, Dipjyoti, Arindam Dey, and Jumrik Taipodia. "Subsurface Profiling Using Roadside MASW Survey: Influence of Multiple Sources and Offline Distance." Journal of Environmental and Engineering Geophysics 27, no. 2 (June 2022): 73–88. http://dx.doi.org/10.32389/21-010.

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Roadside MASW survey utilizes traffic-generated surface wave signals for subsurface characterization and, thus, can be a useful geophysical method, especially in urban areas. However, such signals originating from vehicular movements over road surface irregularities, or sources, produce complex field records of multi-source and multi-azimuthal characteristics. Such sources are termed intra-line if they exist within the receiver spread and outer-line when they exist outside the receiver spread. In a roadside survey, the receiver spread is placed outside and parallel to the centreline of the road, thereby creating an offline distance with respect to the sources on the road. In this study, experimental investigations are conducted to determine the influence of the presence of intra-line or outer-line sources and offline distances of source positioning on the dispersion imaging of roadside MASW records. Artificial hurdles were placed deliberately at different positions on an adjacent road to determine the influence of intra-line and outer-line sources. Furthermore, receiver arrays were placed at varying offline distances with respect to the centreline of the adjacent road to assess the effect of offline distance on the dispersion imaging and subsequent shear wave velocity profile. The study finds that the dispersion images obtained from the intra-line source have better resolutions compared to those obtained from the outer-line source. Further, the presence of multiple sources during the data acquisition does not necessarily shed any detrimental influence on dispersion imaging as long as there is no contamination and mutual interferences of the raw wavefield records. As the offline distance increases, the intensity of the traffic-generated source signal diminishes. It is observed typically for the studied site that beyond an offline distance of 15 m, there remains no recognizable energy to obtain a distinct dispersion image. A comparative study of the shear wave velocity profiles obtained from a borehole, roadside, active, and passive remote MASW surveys revealed an agreeable match, thereby indicating the usability of the roadside MASW survey, especially when offline distance is not enormously large.

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Journal articles on the topic 'MASW'

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