Research of reservoir watershed fine zoning and flood forecasting method

In the present study, a set of correlation relations between standard penetrations tests (SPT-N values) and shear wave velocity (Vs) for different categories of soils is developed for Dholera region, Gujarat state, Western India. Shear wave velocities were measured using multichannel analysis of surface wave (MASW at 42 sites) and by PS logging (at 16 sites). SPT-N values were taken in total 87 geotechnical boreholes at depth interval of 3 m. Seismic site classification is done as per National Earthquake Hazards Reduction Program of the USA. Total 336 pairs of SPT-N values and Vs data at different depths are used to develop the regression correlation between uncorrected SPT-N value and Vs and compared with the results of other workers from India and worldwide for all soils type. It is found that regression correlations developed for clay and all soils are almost similar to each other, for sand, the coefficient value is less and for silt, it is higher. The new regression equation gives good prediction performance. The present correlation can be used for the seismic hazard study for the study area and also for the other areas having similar soil strata using a process of validation.     

Use of Surface Waves in Statistical Correlations of Shear Wave Velocity and Penetration Resistance of Chennai Soils

Shear wave velocity (V _s) is one of the most important input parameter to represent the stiffness of the soil layers. It is preferable to measure V _s by in situ wave propagation tests, however it is often not economically feasible to perform the tests at all locations. Hence, a reliable correlation between V _s and standard penetration test blow counts (SPT-N) would be a considerable advantage. This paper presents the development of empirical correlations between V _s and SPT-N value for different categories of soil in Chennai city characterized by complex variation of soil conditions. The extensive shear wave velocity measurement was carried out using Multichannel Analysis of Surface Waves (MASW) technique at the sites where the SPT-N values are available. The bender element test is performed to compare the field MASW test results for clayey soils. The correlations between shear wave velocity and SPT-N with and without energy corrections were developed for three categories of soil: all soils, sand and clay. The proposed correlations between uncorrected and energy corrected SPT-N were compared with regression equations proposed by various other investigators and found that the developed correlations exhibit good prediction performance. The proposed uncorrected and energy corrected SPT-N relationships show a slight variation in the statistical analysis indicating that both the uncorrected and energy corrected correlations can predict shear wave velocity with equal accuracy. It is also found that the soil type has a little effect on these correlations below SPT-N value of about 10.     

Subsurface characterization using seismic refraction and surface wave methods: a case of Lagos State University, Ojo, Lagos State

This study contains the finding of geophysical investigations conducted at the proposed science complex site at Lagos State University, Ojo, Lagos, Nigeria. Surface wave and seismic refraction tests are non-invasive seismic techniques and have been used to determine the shear wave velocity profile of soil deposits. The methods provide a simplified characterization of subsurface in two-dimensional (2D) (distance and depth) profiles. Seismic records obtained were processed/analyzed by Seis-Imager software to obtain one-dimensional shear wave velocity (Vs) distribution. Multiple Vs obtained were integrated and used to construct two-dimensional Vs map. The measured P- and S-wave velocities were also used to estimate Poisson’s ratio, rigidity modulus, and N-values. The study had shown that the area investigated composed mainly of loose sediments (clay formation) to the depth of 12 m with P-wave velocity ranging between 125 and 205 m/s and corresponding S-wave velocity between 60 and 100 m/s. The results presented in this study will be vital information for the engineers in construction of the proposed science complex.     

Variations in shear wave velocity and soil site class in Kolkata city using regression and sensitivity analysis

The detrimental effects of an earthquake are strongly influenced by the response of soils subjected to dynamic loading. The behavior of soils under dynamic loading is governed by the dynamic soil properties such as shear wave velocity, damping characteristics and shear modulus. Worldwide, it is a common practice to obtain shear wave velocity (V _s in m/s) using the correlation with field standard penetration test (SPT) N values in the absence of sophisticated dynamic field test data. In this paper, a similar but modified advanced approach has been proposed for a major metro city of eastern India, i.e., Kolkata city (latitudes 22°20′N–23°00′N and longitudes 88°04′E–88°33′E), to obtain shear wave velocity profile and soil site classification using regression and sensitivity analyses. Extensive geotechnical borehole data from 434 boreholes located across 75 sites in the city area of 185 km² and laboratory test data providing information on the thickness of subsoil strata, SPT N values, consistency indices and percentage of fines are collected and analyzed thoroughly. A correlation between shear wave velocity (V _s) and SPT N value for various soil profiles of Kolkata city has been established by using power model of nonlinear regression analysis and compared with existing correlations for other Indian cities. The present correlations, having regression coefficients (R ²) in excess of 0.96, indicated good prediction capability. Sensitivity analysis predicts that significant influence of soil type exists in determining V _s values, for example, typical silty sand shows 30.4 % increase in magnitude of V _s as compared to silt of Kolkata city. Moreover, the soil site classification shows Class D and Class E category of soil that exists typically in Kolkata city as per NEHRP (Recommended provisions for seismic regulations for new buildings and other structures—Part 1: Provisions. Prepared by the Building Seismic Safety Council for the Federal Emergency Management Agency (Report FEMA 450), Washington, DC, 2003) guidelines and thereby highlighting the seismic vulnerability of the city. The results presented in this study can be utilized for seismic microzonation, ground response analysis and hazard assessment for Kolkata city.

     

Surface wave studies for shear wave velocity and bedrock depth estimation over basalts

Shear wave velocity (V _S) estimation is of paramount importance in earthquake hazard assessment and other geotechnical/geo engineering studies. In our study, the shear wave velocity was estimated from ground roll using multichannel analysis of surface wave (MASW) technique making use of dispersive characteristics of Rayleigh type surface waves followed by imaging the shallow subsurface basaltic layers in an earthquake-prone region near Jabalpur, India. The reliability of MASW depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Inversion of data from surface waves resulted in a shear wave velocity (V _S) in the range of 200–1,200 m/s covering the top soil to weathering and up to bedrock corresponding to a depth of 10–30 m. The P-wave velocity (V _P) obtained from refraction seismic studies at these locations found to be comparable with V _S at an assumed specific Poisson’s ratio. A pair of selected set of V _S profiles over basalt which did not result in a hazardous situation in an earthquake of moderate magnitude are presented here as a case study; in other words, the shear wave velocity range of more than 200 m/s indicate that the area is highly unlikely prone to liquefaction during a moderate or strong earthquake. The estimated depth to basalt is found to be 10–12 m in both the cases which is also supported by refraction studies.     

Geospatial contour mapping of shear wave velocity for Mumbai city

Shear wave velocity is one of the most important input parameter in the analysis of geotechnical earthquake engineering problems, particularly to estimate site-specific amplification factor and ground response study. Dynamic in situ tests such as spectral analysis of surface waves (SASW) or multichannel analysis of surface waves (MASW) are very expensive. Also due to lack of specialized personnel, these tests are generally avoided in many soil investigation programs. Worldwide, several researchers have developed correlations between the SPT ‘N’ value and shear wave velocity ‘V _s’, which are useful for determining the dynamic soil properties. In the present study, more than 400 numbers of soil borehole data were collected from various geotechnical investigation agencies, government engineering institutes and geotechnical laboratories from different parts of Mumbai city, which is financial capital of India with highest population density. In this paper, an attempt has been made to develop the correlation between the SPT ‘N’ value and shear wave velocity ‘V _s’ for various soil profile of Mumbai city and compared with other existing correlations for different cities in India. Using Geographical Information System (GIS), a geospatial contour map of shear wave velocity profile for Mumbai city is prepared with contour intervals of 25 and 50 m/s. The scarcity of database or maps of shear wave velocity profile for Mumbai city will make the present geospatial contour maps extremely useful and beneficial to the designer, practitioners for seismic hazard study involved in geotechnical earthquake engineering.     

Multichannel analysis of surface waves (MASW) for seismic site characterization using 2D genetic algorithm at Bahrah area,Wadi Fatima,Saudi Arabia

The present study deals with the seismic site classification of Bahrah area, Wadi Fatima, to characterize the local site conditions. The dynamic behavior of sediments was studied by the application of surface wave inversion. The multichannel analysis of surface waves (MASW) shallow geophysical technique was utilized for site classification. MASW survey was carried out at 66 sites along with 13 seismic refraction profiles at suitable localities. MASW and seismic refraction profiles were processed and compared with the available borehole data. The integration of MASW techniques with seismic refraction and borehole data progressively enhanced the subsurface visualization and reliability of the shear wave velocity estimation in the subsurface in the study area. The subsurface shear-wave velocity model was achieved by the solution of an inverse problem-based dispersion of surface waves and propagation in a vertically heterogeneous medium. The 2D genetic algorithm was employed for the inversion of dispersion curves to obtain velocity and thickness of subsurface layers. The depth to engineering bedrock and velocity of shear waves in the first 30 m was deciphered and mapped. The depth of bedrock in study area varies from 4 to 30 m, and V _{S 30} ranges from 320 to 800 m/s. The most of study area falls in B and C class categories in addition to few sites of D class according to the NEHRP guidelines.     

NEHRP soil classification and estimation of 1-D site effect of Dehradun fan deposits using shear wave velocity

Shear wave velocity of the near surface soil at nearly 50 sites in the sub Himalayan mountain exit covering Doon fan deposits, was determined using Multi-channel Analysis of Surface Waves (MASW), a seismic reflection technique. Based on the average shear wave velocity of the upper 30 m soil column, sites in the Dehradun fan are predominantly classified as class ‘D’ (180–360 m/s). Similarly, sites located on the northwestern, eastern and southeastern sides of the fan deposit have shear wave velocities (in the upper 30 m soil) greater than 360 m/s, thereby classifying them as class ‘C’ (360–760 m/s) in accordance with NEHRP provisions. Some of the sites towards the southwestern side of the fan deposits had average shear wave velocities less than 180 m/s and could be classified as soil class ‘E’. One dimensional site effects, including amplification and dynamic period were calculated for the majority of the sites. However, some of the representative suite of sites across the north–south profile of Dehradun fan has been discussed here. Although the attenuation is greater on the southwestern side of the Dehradun fan deposits (i.e. thicker, low velocity sediments) and the sites had been classified as class ‘D’ and ‘E’ but the site amplification tends to be greater in the northern and northwestern part of the city due to large impedance contrast with in the near surface soils.     

Seismic microzonation for Penang using geospatial contour mapping

Shear wave velocity (V _s) and the fundamental site period of the subsurface condition are the primary parameters that affect seismic soil amplification in particular sites. Within the topmost layer of the soil, which measures 30 m, the average shear wave velocity V _s30 is commonly used to build codes for site classification for the design of earthquake-resistant structures and to conduct microzonation studies. In this study, the development of a microzonation map for V _s30 distribution, National Earthquake Hazard Reduction Program V _s30 site classification, and a fundamental site period for Penang are presented. The multichannel analysis of surface wave (MASW) test was conducted for more than 50 sites with available borehole data to develop the microzonation maps. The ten selected V _s profiles measured by MASW show a good correlation with the data obtained using empirical correlations in a previous study. The highest V _s values were identified at the northeastern and southeastern parts of Penang Island, corresponding to the shallow bedrock and the outcrop zone. Conversely, the lowest V _s values were found in the northwestern and southwestern parts of the Penang mainland owing to the thick layer of soft clay and silt deposits. The site period map shows the variation in site periods, with the highest value of 1.03 s at the western part of the Penang mainland and the lowest value of 0.02 s at the eastern part of the Penang Island. The microzonation maps developed in this study are vital to studies on seismic hazard and earthquake mitigation programs in Malaysia.     

Application of seismic velocity tomography in investigation of karst collapse hazards,Guangzhou, China

This paper describes seismic velocity tomography applied to the investigation and assessment of karst collapse hazards to facilitate accurate characterization of geological conditions of karst sinkhole formation. In the survey areas of Xiamao, Guangzhou, China, and Huangchi, Foshan, China, seismic velocity tomography was used to explore the structures of rock and soil associated with karst collapse. The results show that sand intercalated with clay or clay intercalated with soft soil dominates the cover of these two areas. The overburden is 20–33 m thick and underlain by Carboniferous limestone. In the limestone, there are well-developed karst caves and cracks as well as highly fluctuating bedrock surfaces. The seismic velocities are less than 2500 m/s in the cover, 2500–4500 m/s in the karst fracture zones and caves of Xiamao, and 1500–2000 m/s in the Huangchi collapse area. The karst fracture zones, relief of bedrock surfaces, and variations of soil thicknesses revealed by seismic velocity tomography are well constrained and in agreement with those in the drilling borehole profiles. This paper demonstrates that seismic velocity tomography can delineate anomalies of rock and soil with the advantages of speed, intuitive images, and high resolution.     

Microtremor study for evaluating the site response characteristics in the Surat City of western India

The Surat City, which is the second most populated city in the state of Gujarat in western India, warrants site-specific seismic hazard assessment due to its rapid urbanization and proximity to major seismogenic zones. This study reports results of microtremor investigations at 72 single stations and 4 arrays in an area of 325 km² spanning the city. The resonant frequencies, associated peak amplification values and liquefaction vulnerability indices were deduced from the horizontal to vertical spectral ratios. Ground amplification (A_HVSR) in the range of 3.0–5.0 was observed in the 2.0–4.0-Hz frequency band at most of the sites. A secondary A_HVSR between 2.0 and 3.0 is also observed in the 6.0–7.0-Hz frequency band at a few sites. Locales that are most susceptible to liquefaction are identified based on their vulnerability index (K _g) exceeding the value of 10. The shear wave velocities (V _s) ≥ 500 m/s inferred from array measurements occur at 38 m depth in the western part and ~16 m depth in the eastern part of city. The response spectra estimated from strong motion data recorded at an accelerograph site in Surat from three earthquakes of M _w ≥ 3.2 that occurred in Kachchh, Saurashtra and Narmada regions are in accordance with our inferences of characteristic site frequencies and amplification. Our results, in agreement with the damage scenario during the 2001 Bhuj earthquake, provide valuable inputs for site-specific seismic hazard evaluation of the Surat City.     

Application of MASW in road failure investigation

Multichannel analysis of surface waves (MASW) survey was conducted to measure shear wave velocities in order to ascertain the likely causes of road failure along LASU-IBA expressway in Alimosho local government area, Lagos, Nigeria. MASW data were acquired along the express road. The acquired dataset was processed and transformed into two-dimensional structure reflective of depth and surface wave velocity distribution within a depth of investigation using SurfSeis software. The MASW shear wave velocity data were compared to geophysical data that was acquired along the same profile. The comparison was also done with geotechnical data that had been acquired prior to the study some meters away from the study area. The correlation between N values to measured shear wave velocity using MASW was generated. The comparison illustrates the accuracy and consistency of MASW-derived shear wave velocity profiles. We concluded that (1) the low-velocity region that varies between 100 and 250 m/s at surface down to 4 m beneath the surface is characterized by loose/peat materials and may have been responsible for the road failure within the study area; this region depicts a very loose compaction area. (2) The MASW technique is a time–cost-effective tool for obtaining reliable shear wave velocity profiles, and (3) the MASW is particularly attractive in areas that cannot be readily assessed by other geophysical and geotechnical tools.     

Shear Wave Velocities in the Estimation of Earthquake Hazard Over Alluvium in Seismically Active Region

It is well known that the potential hazard during an earthquake is mainly in alluvium or alluvium filled basins; shear wave velocity plays a significant role in estimating the possible hazard during an earth quake in such an area. This paper presents shear wave velocity profile from Jabalpur, Central India mainly dominated by alluvial soil that was moderately affected by an earthquake of magnitude 6.5 in May, 1997. The acquired shear wave velocity by Multichannel Analysis of Surface Wave (MASW) in as many as 36 sites over alluvial soil ranges from 200 m/sec to 400 m/sec and in a few sites marginally less than 200 m/sec corresponding to a sub-surface depth of 30–35 m. Further, the computed N values vary as low as near zero to less than 25. The study is substantiated by the estimation of P-wave velocity by refraction seismic method at the same locations of MASW which ranges from 350 m/sec to 2200 m/sec. The results suggest that the damage during an earth quake appears to be highly unlikely in view of the marginally high Vs up to depth of 30 m. This study on seismic hazard is substantiated by the estimation of frequency of the ground as well as amplification which is found to be a maximum of about 2.5 in the frequency band of 2–6 Hz in west and north western portion of the study area.     

主-被动源地震面波勘探方法在岩溶区浅覆盖层探测中的应用

采用主-被动源地震面波勘探方法,对桂林市兴安县典型浅覆盖层实验区三维地质结构进行探测研究。结合主-被动源面波数据提取的频散曲线,拓宽了频带,提升了低频信号的分辨率。实验结果显示,测区内地下介质横波速度值范围为161.5~519.5 m/s, 根据速度值的差异将实验区地下介质大致分为4个层位,第一层速度范围为161.5~281 m/s, 第二层速度范围为281~360.5 m/s, 第三层速度范围为360.5~400.2 m/s, 第四层速度范围为400.2~519.5 m/s。结合钻孔资料,对应的第一层岩性为粘土层,第二层为粉砂质粘土,第三层为细砂-砂砾岩,第四层为灰岩,且局部土洞、溶洞等构造发育。研究结果表明,瑞雷面波勘探方法能够较准确地刻划浅覆盖层地下介质土层厚度、结构分布及土层与基岩面接触带起伏形态。     

Deterministic and probabilistic seismic hazard analysis for Gwadar City, Pakistan

Gwadar City is located at the coastline of Pakistan. The city is currently in a phase of development, which is expected to become a future economic hub for Pakistan. This has led us to choose Gwadar for seismic hazard evaluation. Seismic hazard analysis for Gwadar is carried out using deterministic and probabilistic seismic hazard analysis techniques. The present study will help in sustainable development of a future large city and economic hub for Pakistan on ways of coping from a major threat of earthquake hazard. In deterministic seismic hazard analysis, line sources were identified close to Gwadar. Based on the analysis of maximum magnitude and closest distance (worse conditions), Makran subduction zone was identified out of all the line sources with earthquake potential of 8.2 at a distance of 30 km. This yielded a peak ground acceleration value of 0.38 g for Gwadar City. In second phase, probabilistic seismic hazard analysis technique with the area source modeling was adopted to acquire results at different return periods. For this purpose, seismic data were collected from the Pakistan Meteorological Department and International Seismological Center (2010) databases for development of a comprehensive data catalog. The a and b values were obtained using regression analysis for each source zone, and probabilistic analysis yielded the results of 0.34 g for a return period of 500 years. As per building codes of Pakistan, areas or cities with ground acceleration greater than 0.32 g are considered in seismic zone 4, and both deterministic and probabilistic hazard analysis place the city in seismic zone 4. These values correspond to rock site with shear wave velocity of 760 m/s.     

Soil responses near Delhi ridge and adjacent regions in Greater Delhi during incidence of a local earthquake

In this study, soil response was carried out for the Greater Delhi region. A folded Proterozoic formation was identified as Delhi ridge, passes through its central part along SSW–NNE direction, and appears to be a main geomorphic feature for the study area. The Delhi ridge is an exposed quartzite rock of about 10–100 m wide and ~25 km long with gentler dipping both toward east and west. We have considered the exposed part as an outcrop side near the ridge axis and the dipping area as rigid base away from the ridge axis for ground motion study during the occurrence of the 25 November 2007 earthquake with magnitude M _L 4.3 (Richter scale) that occurred at Delhi–Haryana State boundary. The degree of shaking was very strong and reported major cracks in the buildings near the epicenter area. We have studied the soil response parameters at the surface level, considering horizontally stratified soil layers above rigid base. The equivalent linear method was used for soil response analysis at 25 sites in Greater Delhi area. The peak amplification factors vary from 3.2 to 5.9 and peak resonance frequency varies from 1.2 to 5.3 Hz. The correlation among the peak amplification factor (A) and frequency (f) was empirically established as A = 0.36f + 3.60. Increasing peak amplification factor was found at sites with increasingly thicker alluvium deposit with lower frequency contains ground motion and vice versa. Seismic zoning map was also reconstructed for peak amplification factors and predominant periods for the study area for the mitigation purposes of earthquake damage. The average shear wave velocity up to 30 m soil depth is also obtained for site classification. The average velocity to 30 m [ $ \overline{{V_{\text{s}} }} (30) $ ] is a widely used parameter for classifying sites for predicting their potentiality to amplify seismic shaking. A lower value [ $ \overline{{V_{\text{s}} }} (30) $ ] thus yields a more conservative estimate of ground motion, which generally increases as $ \overline{{V_{\text{s}} }} (30) $ decreases. Present estimate of $ \overline{{V_{\text{s}} }} (30) $ varies from 315 to 419 m/s. In this study, we have identified two site classes C and D, as per National Earthquake Hazard Reduction Program. The city planner or engineers can directly use these data for site-specific assessment during retrofitting of the existing structure, demolition of the old buildings and design a new structure to avoid major destruction of the buildings due to future earthquake.     

基于SCPTU的软土最大剪切模量测试分析研究

最大剪切模量是土的基本力学特性参数,对土动力特性分析和岩土工程抗震设计有着重要的意义。目前最大剪切模量的确定主要依赖于室内试验,土样的采取和室内试验既耗时又不能保证精度。以江苏北部里下河古泻湖相软土地区高速公路建设为工程背景,采用地震波孔压静力触探（SCPTU）和下孔法（DHT）进行了土层剪切波速的测试,基于SCPTU和DHT剪切波速测试资料建立了最大剪切模量Gmax与SCPTU测试参数之间的相关关系。结果表明：采用SCPTU测试的锥尖阻力和孔压参数能够用于对软土的最大剪切模量的初步评价。     

Estimation of freeboard requirements against overtopping of surface impoundments under seismic action

The excitation of structural components and liquid contents of surface impoundments by seismic waves can generate turbulence that is large enough to overtop the bounding berms. In cases in which the liquids are wastes from industrial/municipal operations, their release from impoundments can pose significant risks to the environment. In this analysis, the freeboard magnitudes that can accommodate liquid head levels in impoundments are determined through linkage of configuration of waves in the liquid surface to incident seismic wave characteristics, liquid characteristics and impoundment design. For an impoundment site in a region of ground acceleration levels ranging from 0.2 to 1.0 g and impacted by seismic shear wave velocity of 180 m/s, freeboard requirements are in the range of 0.004–2.0 m on soft soil; 0.008–0.7 m on medium-dense soil; and 0.002–0.1 m for dense soil. For the same impoundment design, ground acceleration and incident wave characteristics, freeboard requirements are directly proportional to the depth of the soil mantle over bedrock. The impoundment slope, which is a key parameter with regards to liquid holding volumetric capacity of the impoundment, is a less significant parameter than depth to bedrock with regard to the size of the required freeboard. This implies that siting of an impoundment should be considered to be critical to impoundment performance in seismic zones.     

Geologic site conditions and site coefficients for estimating earthquake ground motions in the inland areas of Korea

Site characterization and site-specific ground response analyses were conducted at two representative inland areas in Korea. In situ tests included 25 boring investigations, 7 crosshole tests, 18 downhole tests and 41 SASW tests, and in the laboratory, resonant column tests were performed. The soil deposits in Korea, which were shallower and stiffer than those in the western US, were examined. The fundamental site periods were distributed in the narrow band ranging from 0.1 to 0.4 s. Most sites were designated as site classes C and D based on the mean shear wave velocity of the upper 30 m from the current Korean seismic design guide. Based on the ratio of the acceleration response spectra of ground surface to rock-outcrop, short-period (0.1–0.5 s) site coefficient, F_a ranged from 1.0 to 2.7, and mid-period (0.4–2.0 s) site coefficient, F_v ranged from 1.0 to 1.6, regardless of the input rock outcrop acceleration levels of 0.05 and 0.14 g. The site coefficients specified in the Korean seismic design guide, which is similar to NEHRP provisions and UBC, underestimate the ground motion in the short-period band and overestimate the ground motion in the mid-period band. These differences can be explained by the differences in the depth to bedrock and the soil stiffness profile between Korea and western US. Also, the site coefficients should be re-evaluated accounting for the local geologic conditions on the Korean peninsula.     

An Experimental Characterization of Shear Wave Velocity (V<Subscript>s</Subscript>) in Clean and Hydrocarbon-Contaminated Sand

The characteristics of hydrocarbon-contaminated soils have been among major concerns of geotechnical engineers due to its significant frequency of event and also its influential consequences on our surroundings from various environmental and engineering viewpoints. Heretofore, the effects of diverse kinds of hydrocarbon contaminants on majority of geotechnical properties of fine- and coarse-grained soils such as grain size, hydraulic conductivity, plasticity, compressibility, internal friction, cohesion, and shear strength have been investigated. However, there has not been a concentrated research study examining shear wave velocity (\({\text{V}}_{\text{s}}\)) of hydrocarbon-contaminated soils as an important geotechnical property of soil due to this fact that, in small/very small strain levels, the maximum shear modulus of soils (\({\text{G}}_{ \hbox{max} }\)) can be determined using shear wave velocity (\({\text{G}}_{ \hbox{max} } =\uprho{\text{V}}_{\text{s}}^{2}\)). This paper aims to investigate effects of hydrocarbon contamination on shear wave velocity of sandy soils by comparing shear wave velocities in identically prepared clean and contaminated samples. To this aim, an Iranian light crude oil, a standard type of silica sand (Ottawa sand), and a bender element apparatus were used to minutely measure shear wave velocity of clean and crude oil contaminated sand samples. Moreover, dry and quasi-moist tamping methods were employed in order to provide comparable clean and contaminated specimens (containing 4, 6, 8, 10, and 12 wt% of crude oil), respectively. Firstly, a comprehensive bender element (BE) and resonant column tests were conducted on the identically prepared clean sand samples at various amounts of frequency (2–20 kHz) and under various confining pressure (50–500 kPa) to find the best methods of accurately determining shear wave travel time in BE tests. Thereafter, BE tests were conducted to examine shear wave velocity in contaminated specimens. Based on the results, it was found that there was a critical value for crude oil content with the maximum shear wave velocity so that shear wave velocity of 4 wt% contaminated sand (V_s-4 wt%) was about 1.2 times higher than clean one (V_s-clean), and contrastingly adding further crude oil up to 6 wt% made a significant reduction in value of shear wave velocity to some extent that V_s-6 wt% was slightly lower than V_s-clean (V_s-6 wt% = 0.95–0.97V_s-clean). Moreover, adding more contaminant (8–12 wt%) into sand had negligible influences on shear wave velocity. In this paper, the effects of crude oil contamination on sand microstructure were also evaluated using scanning electron microscopy.