Multichannel Analysis Of Surface Waves Survey Research Articles

Seismic site characteristics for geotechnical engineering purposes: Case study, South of Ras Samadai, Red Sea, Egypt

Nowadays, geophysical techniques are widely employed in geotechnical research. Among the techniques that are frequently employed is the Multichannel Analysis of Surface Waves (MASW) technique, it aims to depict spatial differences in physical characteristics of the subsurface layers. The aim of the current research is to produce multiple maps for the seismic site classification (SSC) and dynamic characteristics along the study area located on the Red Sea shoreline of Egypt, south of Ras Samadai. In order to achieve this goal MASW surveys have been conducted in the current study, and corresponding 1D-shear wave velocity profiles have been generated. Consequently, to trace the stiffness change in the subsurface layers, the study provides a series of maps using the shear wave velocity (Vs) values at different depths to help the geotechnical engineers to identify and mitigate the geotechnical potential risk. Additionally, The Vs30 map for the study site is prepared and classified in accordance with the EC8 classification system. Referring to the obtained Vs30 map, the study region is mostly described as category B, with limited zones falling under classes A and C. Moreover, the soil's dynamic properties, including soil amplification and site natural period have already been taken in consideration. Approximately, the whole region exhibits low-to-moderate amplification values. However, two constrained zones are significantly more susceptible to amplification. Furthermore, the studied area is divided into six separate zones according to the obtained isoperiod map. The obtained results could be applied to engineering problems contribute to soil to avoid the probable obstacles during construction on soft soil.

A multi-scenario based micro seismic hazard assessment of the Bhuj City, western India incorporating geophysical and geotechnical parameters

The micro-seismic hazard assessment (micro-SHA) of the Bhuj city (highest seismic zone V) has been accomplished considering seismotectonic as well as shallow subsurface modeling through geophysical (multi-channel analysis of surface waves (MASW) survey at 19 sites) and geotechnical parameters from 28 boreholes distributed in the entire Bhuj city. The average shear wave velocity through the MASW survey at 30 m depth (VS30) is estimated in the range of 400–915 m/s (NEHRP C-type and B-type soil classes). Seismotectonically justified a total of 54 scenario-earthquakes (SEQs) along all major faults have been considered to evaluate the strong ground motion at generic soil level having a shear wave velocity of 760 m/s and depth of 12–28 m. The surface level strong motion (SM) has been estimated through ground response analysis preparing soil models along all boreholes. The PGA at the surface in Bhuj city has been estimated in the range of 528 cm/s2 to 1020 cm/s2; highest in the central-western part of the Bhuj city where clay with high plasticity is present. The mean-spectral acceleration over the study area for 0.2 s (corresponding to 1-2 story), 0.55 s (4-5 story), 1sec (high rise) and 1.25 s period (large structures) are prepared at the surface from all scenario earthquakes. The amplification of SM in the Bhuj city is computed in the range of 1.7–3.7.

Seismic site characterization using MASW and correlation study between shear wave velocity and SPT[sbnd

A seismic site characterization study is carried out in the south of the foothills of tectonically active Himalayan region. During an earthquake, the dynamic characteristics of the shallow subsurface strata can influence seismic shaking in the region, causing damage to civil infrastructures. The seismic site characterization study with shear wave velocity (Vs) is performed using the Multi-channel Analysis of Surface Wave (MASW) technique, which is particularly challenging to implement in the densely inhabited areas. However, the standard penetration test (SPTN) commonly measured by civil engineers can be utilized to compute Vs of such areas by establishing a correlation between Vs and the SPT-N values.In the study area, MASW data were acquired at twelve different locations, whereas SPT-N tests were available from 26 boreholes. Twelve borehole locations closer to the MASW survey lines were paired to establish relationships between SPT-N and Vs. The developed linear and non-linear correlation functions were found to be statistically similar. Furthermore, the linear correlation function is used for estimating Vs from SPT-N in remaining 14 boreholes. The new correlation functions were further compared with previously reported empirical relationships from other areas. The current relationship can be used for geoengineering purposes at different sites with similar geological conditions.Shear wave velocity derived from the MASW surveys and estimated from the new empirical relationship was utilized for seismic site characterization based on average shear wave velocity up to 30 m depth (Vs30). The Vs30 map of the study site is prepared and classified in accordance with the National Earthquake Hazard Reduction Program (NEHRP-2020). The calculated Vs30 value of the study site ranges from 285 to 375 m/s. The major portion of the study area lies under Site Class CD, with a minor portion under Site Class D. In the event of an earthquake, some zones can potentially have stronger ground amplification, particularly in Site Class D and may have damaging effects. A series of average shear wave velocity maps for different depths are prepared to help geotechnical engineers in identifying and mitigating geotechnical risks. Furthermore, there are potential geohazard risks as certain depths show low shear velocity.

Geophysical techniques for characterisation of municipal solid waste landfills

This paper presents the seismic site characterisation of Mavallipura landfill in Bengaluru, India using multichannel analysis of surface waves (MASW). The survey was performed at top level up to a height of 25 m. Up to 6 m it consisted of uncompacted waste. Also, the shear-wave velocity increased with depth from approximately 74 to 150 m/s. A series of one- and two-dimensional MASW surveys at various levels of the landfill was carried out to map the site fully. A new empirical correlation between standard penetration test corrected N values and shear-wave velocity was also developed. The MASW survey results and correlation with the conventional geotechnical investigation are presented in this paper. The results showed that the seismic waves can achieve changes in shear-wave velocity and Poisson's ratio to conclude the amount of degradation taking place at the landfill and thereby provide some knowledge with regards to the properties required for evaluating seismic stability.

A critical insight into the influence of data acquisition parameters on the dispersion imaging in passive roadside MASW survey

Passive roadside method of multichannel analysis of surface wave (MASW) is a simple passive technique of subsurface exploration that can provide deeper subsoil investigation compared to conventional active MASW technique. However, attributed to the lack of thorough experimental validation with other techniques and establishment of various acquisition parameters, the number of real world applications of the method is scanty. The paper presents the results of extensive experimentation to highlight the importance of two primary acquisition parameters, namely the length of receiver array and acquisition time, on the dispersion imaging of roadside survey at sites comprising different traffic volume. The length of receiver array directly affects the resolution of dispersion image and the estimated depth of shear-wave velocity profile. Thicker energy band and poor resolution in the lower frequency band of dispersion image are found to be the outcome of utilizing smaller arrays. The span of acquisition time is a site dependent parameter and is governed by the volume of the traffic and number of existing sources on the road surface nearby the test site. Comparatively smaller recording time is found effective in producing dispersion images with sufficient resolution in a heavier traffic volume case. The paper also illustrates a detailed comparison of results obtained from roadside and active survey in terms of the dispersion imaging and shear wave velocity profiles at the specific sites.

Delineation of Potential Groundwater Zones Using Shear Wave Velocity in Eastern Deccan Volcanic Province, India

A comprehensive study based on Multichannel Analysis of Surface Waves (MASW), a near-surface geophysical technique, was carried out for the first time in the Mandla Lobe of the Eastern Deccan Volcanic Province. The study was conducted to demarcate fractures, which are essential for finding potential groundwater zones in the hard rock region and for the delineation of shallow subsurface geological features in terms of shear wave velocity. The MASW surveys were carried out at different selected locations in the study area to delineate fractures in the basaltic terrain covered with thin weathering and alluvium cover. These basalts are mainly comprised of massive, vesicular and amygdaloidal varieties and interpreted as different basaltic flows of Mandla, Dhuma and Pipardahi formations. The shear wave velocity sections divulge the layered nature of the basalt sequences. In some of the massive flows, there are low-velocity vertical zones that can be deduced to be either vertical columnar joints or fracture zones, and the low-velocity weathered flows can be the good groundwater reservoirs. The shear wave velocities Vs obtained are in the range from 300 to 2500 m/s at different locations, and the thicknesses of flows are varied in the MASW sections. The obtained shear wave data are compared with the borehole data, and the results are well correlated. The study clearly differentiates the variations within basaltic formations, which are interpreted as potential groundwater zones.

Integrated MASW and ERT Imaging for Geological Definition of an Unconfined Alluvial Aquifer Sustaining a Coastal Groundwater-Dependent Ecosystem in Southwest Portugal

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.

One- and Two-Dimensional Active MASW Survey for Subsurface Profiling of Jia Bharali River Bed, Assam, India, for a Proposed 1.2-Km Road Bridge

AbstractThis article describes the active multichannel analysis of surface waves (MASW) survey conducted at the Jia Bharali River Bed, Tezpur Assam, to identify the shear-wave velocity profile of t...

Influence of Source Energy and Stacking on Active MASW Method Dispersion Image

The study investigates the influence of source weight, type of source plate and number of stacking on the resolution of the dispersion image obtained from the active Multichannel Analysis of Surface Waves (MASW) method at peat soil condition. Fundamental-mode dispersion curve determination is governed by the optimum configuration of the active MASW method. Optimum configuration will ensure reliable inverted shear wave velocity profile. The heterogeneity and problematic characteristics of peat soil provide challenges on the MASW survey. Based on the field tests conducted, the effect of the source weight was significant. Heavier source weight relatively increases the dispersion image resolution especially at lower frequencies but sacrificing the resolution at higher frequencies. Therefore, heavier source weight (i.e. 7 kg sledgehammer) was recommended for deeper depth of investigation with little concern on the shallow depth. The use of rubber plate also contributed to the increases of energy accumulation at lower frequencies. Increasing number of stacking increases the overall energy band as the stacking allows significant suppression of the ambient noise. 5 to 10 stacks were recommended for peat soil condition. Finally, overall comparison between the dispersion images obtained at both locations shows that thicker peat soil layer results in lower resolution and low signal-to-noise ratio dispersion image.

In Situ Shear Wave Velocity From Multichannel Analysis of Surface Waves (MASW) Tests at Six Sites of Delhi Technological University

In the mid-1980s, the surface wave method was initially exhibited as an instrument for the geotechnical engineering field. This non-obtrusive seismic method of multi-channel examination of surface waves is prominently used to draw out the shear-wave velocity profile (variation of soil with respect to its depth). In an attempt to increase the sureness in the construed shear wave velocity (Vs) profile as a result of the ambiguity in the analysed dispersion characteristics, the multichannel method is used in this research to characterize six test sites on the campus of Delhi Technological University, Delhi. The multi-channel analysis of surface waves (MASW) method commenced from the traditional seismic survey method that engages twenty-four receivers positioned all along a linear survey track. The current study implies results from MASW survey at six sites within the DTU campus, for which the MASW data acquisition comprise of the use of a 24-channel PASI seismograph and 24 numbers of 4.5 Hz Vertical geo-phones set apart at 2 m each and source offset (2 m,4 m). The seismic power source was a steel sledgehammer (15 lbs). In order to develop and invert the surface-wave seismic data in addition to creating the one-dimensional depth versus Shear Wave Velocity (Vs) profiles WinMasw software was used. The mean shear wave velocity of the current study area is 285 m/sec. The mean shear wave velocity for Delhi city is in a range of 110 to 350 m/s.

MASW survey to estimate the unit weight of municipal solid waste at a landfill in Brazil

Non-invasive and non-destructive geophysical methods, such as the multichannel analysis of surface waves (MASW), can effectively provide useful information about the mechanical properties (stiffness and unit weight) of municipal solid waste (MSW), during and after landfill operation, for environmental monitoring and engineering analysis. This paper aims to address the results of a seismic survey performed at a sanitary landfill located 40 km north of Rio de Janeiro, Brazil, to image shear-wave velocity profiles to a depth of about 20 m. Seismic data were collected using the MASW method, performing an active and passive combined survey. Shear-wave velocities were used to compute the in situ unit weight distribution of MSW according to the empirical model proposed by Zekkos et al. Results indicated a two-layer model in which the bottom high-velocity layer is stiffer and denser than the top low-velocity layer. Despite the fact that the unit weight appeared to be underestimated for the upper low-velocity layer, model predictions may be graded qualitatively as excellent and potentially more accurate with well-calibrated parameters.

Geotechnical site investigation for tunneling and underground works by advanced passive surface wave survey

This study introduces crosscorrelation seismic interferometry, a new and feasible complimentary surface wave survey for geotechnical site investigation for tunneling and underground works. Crosscorrelation seismic interferometry uses ambient noise as source to estimate the green’s functions received by geophones. The proposed methodology is presented and demonstrated by three case studies in Singapore. The 1st case study demonstrates the workflow of the proposed method. Conventional active multichannel analysis of surface waves (MASW) and passive microtremor array measurement (MAM) have also been carried out on the same site. The comparison with classic active MASW shows that the dispersion curves and shear wave velocity profiles derived by crosscorrelation are more comparable and reasonable. With multiple signal classification (MUSIC) beamforming, the direction of arrival (DOA) of ambient noise field can be characterized. As the prerequisite of crosscorrelation method, with the known DOA, it also affords the opportunity to measure both Rayleigh and Love waves. The 2nd case study demonstrates that the polarization of shear wave velocities can be distinguished by the proposed method. The 3rd case study shows a feasible way to construct a 2D shear wave velocity profile. In short, with a simple linear array, fewer geophones, crosscorrelation is considered to be an attractive complement to the conventional MAM and MASW survey.

Multi-channel analysis of surface wave method for geotechnical site characterization in Yogyakarta, Indonesia

On May 27th2006, 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.

A state-of-the-art review of passive MASW survey for subsurface profiling

Passive multichannel analysis of surface wave (MASW) is a nondestructive technique capable of exploring soil subsurface to a great depth by utilizing ambient long-wavelength passive surface waves without requiring an active source. The method yields subsurface information in terms of shear wave velocity (Vs) profile of the surveyed area. Vs is a vital dynamic property of soil which has numerous applications in various geotechnical and earthquake engineering problems. The accuracy of final Vs profile obtained by MASW technique primarily depends upon the resolution of the dispersion curve which is plot of frequency-dependent phase velocity of the propagating Rayleigh wave. The present study critically reviews the effects and influences of various geometrical parameters (such as the shape and size of receiver arrays) and the recording and processing parameters (such as acquisition time, sampling frequency, and vertical stacking) that control the quality of raw wavefield data and subsequent dispersion imaging. The study reveals that there is no fixed recommendation for any of the mentioned parameters to be used to obtain a high-resolution dispersion image in case of passive MASW survey. Therefore, extensive experimentations are required to further understand and develop standard guidelines for field experimentation and data processing so as to reinforce the method as a stand-alone technique.

Geophysical investigation of dewatering in Lolo Creek, Southwest Missoula, Montana, USA

Interest in finding the causes of reoccurring late summer dewatering of Lolo Creek, Montana, led to geophysical and hydrogeologic studies to understand the cause and effect relationship between surface water uses, groundwater uses and stream flow, critical to water management decisions. Electrical Resistivity Tomography (ERT), Spontaneous Potential (SP), Multichannel Analysis of Surface Waves (MASW) and Seismic Refraction Tomography methods were used to provide information on potential seepage pathways leading to dewatering of Lolo Creek and the subsurface lithology of the area. Results from the MASW and seismic refraction tomography studies showed the bedrock at depths of about 35 m close to Highway 93 and 27 m at the end of the 288 m East-West seismic line running through Lewis and Clark Drive. ERT results showed a shallow, high- resistive layer underlain by low resistive layers. The Eocene bedrock (mylonite) was found to have a resistivity between 180 and 400 Ωm. A geologic fault was inferred in a 360 m East-West ERT profile. SP measurements around the inferred fault indicate a zone of infiltration, with SP values between −18 mV to −2 mV. A 1D-depth velocity profile obtained from MASW survey located close to East-West ERT profile, indicates a low velocity subsurface between 0 and 39 m, which is interpreted to be fractured bedrock. This fractured, shallow bedrock and associated fault work as a seepage path from the shallow to deep aquifer and could possibly account for dewatering of the Creek during low-flow periods in the late summer.

Identification of Karstic Features in Lateritic Soil by an Integrated Geophysical Approach

Lateritic soils are widely spread across the southern and central parts of India. Lateritic formations usually have soft sediments, entrapped between hard to medium soft lateritic rock, which are leached due to the ingress of water during rainy seasons creating hollow sections or cavities which span over large lengths. Laterites are highly heterogeneous and prone to cavitation due to its weathering process; a sound knowledge of the subsurface condition is required before starting any construction. This study presents the application of integrated geophysical investigation for the identification of cavities at a mega construction site in Kerala State, India. Geophysical survey methods, namely ground penetrating radar (GPR) and multichannel analysis of surface waves (MASWs) techniques, are used to identify the heterogeneities in lateritic soils and localized cavities. The survey areas identified are critical sections of a mega construction project subjected to heavy dynamic and static loads. The preliminary GPR survey is carried out across the study areas at specific interval spacing to identify probable heterogeneities. Confirmative survey or detailed GPR and MASW surveys are carried out at the locations identified in the preliminary survey at close intervals to confirm the presence of an anomaly and identify its location. The anomalies in the GPR radargram are identified by visual inspection and trace amplitude approach. Using MASW survey, a 2D shear wave velocity profile is generated to identify low shear wave velocity zones which confirm the presence of an anomaly. On comparing the data from both GPR and MASW survey techniques, the underground cavities were successfully identified at multiple locations with further crosschecking with borings. The study further provided details on subsurface lithology at survey locations.

The combined use of MASW and resistivity surveys for levee assessment: A case study of the Melvin Price Reach of the Wood River Levee

Capacitively-Coupled Resistivity (CCR) and Multichannel Analysis of Surface Waves (MASW) were performed on the Melvin Price reach of the Wood River Levee that has experienced considerable piping through the foundation soil causing numerous sand boils along the landside toe of the levee. Tests were performed along the centerline crest, the landside toe, and the riverside berm of the levee. This study combined the strengths of MASW and CCR testing to resolve the distribution and stiffness of cohesive and non-cohesive materials in the body and foundation of the levee, where invasive testing was not ideal. MASW and CCR were shown to complement each other in the evaluation. CCR successfully classified the near surface clay and sand deposits along the levee and was particularly effective for soil deposits with a high degree of saturation. MASW revealed that a deeper clay layer, appears to be discontinuous at locations where old river bars cross under the levee. These bars may have eroded portions of the deeper clay layer, locally enhancing seepage rates through the foundation materials and influencing the formation of sand boils during large flood events. The use of MASW and CCR also successfully detected the locations of the major utilities crossing the levee. While CCR was the most effective method for detecting conductive utilities, MASW was more effective at detecting utilities which increased the overall stiffness of the subsurface either due to the utility itself or the backfill material around the utility. A site-specific SPT-Vs correlation was developed from the co-located boreholes and shear wave velocity profiles. Comparison of the correlation with previous studies indicates that soil stiffness and geologic age are important factors affecting SPT-Vs correlations. For levee soil deposits, which are typically young, a lower bound SPT-Vs correlation developed using similar soil deposits to the study area should be considered.

Recommendations for generating dispersion images of optimal resolution from active MASW survey

Multichannel Analysis of Surface Waves (MASW) is proving to be the most recent and popular non-invasive method which can characterize the subsurface in quick and better ways. This article reports a detailed study of active MASW survey conducted in a soil site characterized by the presence of heterogeneous soil stratification with crushed debris. In this regard, the effect of receiver layout and key data acquisition parameters (offset distance, far-field and near-field phenomena, receiver spacing, total receiver spread length and numbers of deployed receivers) on the resolution of the obtained dispersion image is elucidated. The influence of the signal pre-processing parameters such as sampling frequency, sampling length, filtering and muting, is also highlighted. The effect of source characteristics on the quality of the recorded wavefield has been elaborated, and in this context, the enhancement of the resolution of dispersion image by stacking has also been discussed. Based on the outcomes, it is recommended that the sampling frequency and sampling time should be optimal so that complete propagation of wave phases through the geophone array is achieved, while at the same time, the time-stamp suffers minimum noise adulteration. Combined application of band-pass filtering and optimal temporal muting is required to obtain best resolution dispersion images. For sites having predominantly softer soils at the shallower depths (Vs,30 < 100 m/s), an optimal offset of 4–6 m with an inter-receiver spacing of 1 m produces the best resolution dispersion images. The resolution of the dispersion image at the lower frequencies can be increased either by using a heavier source, or adopting multiple stacking of dispersion images generated from low energy impacts.

Assessment of soil compaction properties based on surface wave techniques

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.

Subsurface profiling using integrated geophysical methods for 2D site response analysis in Bangalore city, India: a new approach

Recently, site response analysis has become a mandatory step for the design of important structures. Subsurface investigation is an essential step, from where the input parameters for the site response study like density, shear wave velocity (Vs), thickness and damping characteristics, etc, are obtained. Most site response studies at shallow bedrock sites are one-dimensional (1D) and are usually carried out by using Vs from multi-channel analysis of surface waves (MASW) or a standard penetration test (SPT) for N values with assumptions that soil layers are horizontal, uniform and homogeneous. These assumptions are not completely true in shallow bedrock regions as soil deposits are heterogeneous. The objective of this study is to generate the actual subsurface profiles in two-dimensions at shallow bedrock regions using integrated subsurface investigation testing. The study area selected for this work is Bangalore, India. Three survey lines were selected in Bangalore at two different locations; one at the Indian Institute of Science (IISc) Campus and the other at Whitefield. Geophysical surveys like ground penetrating radar (GPR) and 2D MASW were carried out at these survey lines. Geophysical test results are compared and validated with a conventional geotechnical SPT. At the IISc site, the soil profile is obtained from a trench excavated for a proposed pipeline used to compare the geophysical test results. Test results show that GPR is very useful to delineate subsurface layers, especially for shallow depths at both sites (IISc Campus and Whitefield). MASW survey results show variation of Vs values and layer thickness comparatively at deeper depths for both sites. They also show higher density soil strata with high Vs value obtained at the IISc Campus site, whereas at the Whitefield site weaker soil with low shear velocity is observed. Combining these two geophysical methods helped to generate representative 2D subsurface profiles. These subsurface profiles can be further used to understand the difference between 1D and 2D site response.