MASW Method Research Articles

The Combination of Hvsr and Masw Methods with Landsat 8 Imagery to Assess the Changing Shoreline along the Coastal Area of Central Bengkulu

The Central Bengkulu Regency possesses a coastline measuring 21.8 km, situated in direct proximity to the Indian Ocean. The heightened wave and ocean current dynamics possess the capacity to induce detrimental effects in the form of coastal abrasion along the coastline. This study conducted an examination of the rate of shoreline changes resulting from coastal abrasion in Central Bengkulu Regency, Bengkulu, Indonesia. Horizontal-to-vertical spectral ratio (HVSR) analysis, multichannel analysis of surface waves (MASW), and Landsat-8 remote sensing were all used in the current investigation. The project gets started with conducting field investigations and measurements of geophysical techniques, including the collection of Landsat-8 satellite imagery spanning the period from 1990 to 2020. Additionally, an examination was conducted on the rate at which the shoreline undergoes changes in velocity. In order to determine the increase in change that occurs along coastlines over a period of several decades, a study was carried out during which Landsat-8 satellite images were analyzed. This study investigates the application of the HVSR technique for assessing the seismic vulnerability of the ground and, additionally, the MASW technique for measuring the shear wave velocity of the coastline’s soil. Both of these methodologies are compared and contrasted with one another in this research. The findings indicated that the mean pace of coastline change in Central Bengkulu Regency was 1.5 m/yr, with the maximum velocity recorded at 4.1 m/yr. This high velocity of shoreline change is correlated with the Vs30 value of MASW measurement and Kg of HVSR measurement, where the subsurface soil structure along the coast of Central Bengkulu Regency from Vs30 measurement shows that it is dominated by stiff soil structure that is susceptible to erosion. Outcomes from the study can inform decision-making processes about safeguards and preventative measures to prevent further coastal degradation. HIGHLIGHTS In this paper, we present a framework using application passive and active seismic method with Landsat 8 for knowing the changing of shoreline coastal area in Central Bengkulu Indonesia This study demonstrated that the high velocity of the shifting shoreline is correlated with Vs30 and Kg values The subsurface soil structure is predominantly composed of stiff soil, and the changing shoreline starts at 1.5 mm/yr, which makes the coast of Central Bengkulu vulnerable to erosion GRAPHICAL ABSTRACT

The soil characterization of the region between the Maltepe-Beykoz Fault and the Marmara Sea in İstanbul (Türkiye) with the integrated HVSR (Nakamura technique) and MASW method

Completing the earthquake recurrence period of the Marmara segment, one of the two seismic gaps of the northern Anatolian fault zone, necessitates earthquake hazard studies for Istanbul, considering the population density. This study focuses on determining the soil properties of the study area in the Maltepe district of Istanbul. The Maltepe, with its large population density, stands very close to this fault zone and is vulnerable to earthquake damage. The soil properties such as Vs30, dominant period (T0), and amplification ratio (A0) were determined with the MASW from surface wave analysis methods at 48 points and the HVSR approach of microtremor analysis methods at 26 points. These point-based properties were mapped in the GIS environment, and spatial distribution maps were prepared. In addition, seismic vulnerability (Kg) and effective shear strain (γe) calculations for different acceleration values were carried out to detect deformation-failure on the surface. It was understood from the maps and the 2D cross-sections produced to examine the lateral and vertical changes that the soil conditions in the study area developed under the control of the Maltepe Beykoz fault (MBF). Accordingly, the two sides of the MBF lineament were determined with different geophysical outputs by their different geological origins. Namely, the alluvial part in the coastal part was defined by low Vs30, high period, and Kg values; on the contrary, the more rigid parts located at high elevations were described by relatively high Vs30, low period, and Kg values. In addition, it was understood that the deltaic sediments spread loosely and undulated in the alluvium at the SE part of the MBF lineament. These results obtained in the study are significant for predicting disaster damages and taking precautions before disasters. In addition, the scientific data potential of the outcomes of this study will make future studies, which are carried out to determine other parameters to be used during the taking of the precautions, more accessible.

Penyusunan Peta Koefisien Amplifikasi Berdasarkan Rasio Spektra Percepatan

One of the most important parameters in the building structure design process is an amplification coefficient. The amplification coefficient is needed to propagate a spectra acceleration at bedrock to soil surface. The amplification coefficient can be determined by several methods such as MASW Method, HVSR Method and other methods. One alternative method that can be used in determining the amplification coefficient is to determine the ratio between the ground acceleration at the surface and at the bedrock. Therefore, the purpose of this study was to identify the amplification coefficient in the Province of the Special Region of Yogyakarta with the PSHA method analysis approach by utilizing the shear wave velocity data (Vs30). This research method was carried out in 3 stages, namely data collection, acceleration analysis using the PSHA method, and determination of the amplification coefficient based on the acceleration ratio. The results of the study obtained a distribution of the amplification coefficient of the acceleration spectra of 0.2 and 1 second in the DIY province with a maximum value of Fa amplification coefficient was 1.414 on hard soil conditions and 1.653 on medium soil conditions. The maximum Fv amplification coefficient was 1.508 on hard soil conditions and 1,923 on medium soil conditions.

Shallow subsurface investigations for soil properties at Pedas, Negri Sembilan, Peninsula Malaysia using MASW, ERT,IP, and TEM methods

ABSTRACT The development of hot spring tourism projects receives more interest in Malaysia. The country has several hot springs utilized mostly as recreational complexes. Three geophysical methods were applied (MASW), (ERT), and (TEM). Both ERT and TEM are related to the electric properties of the subsurface geological structures, whereas MASW is more sensitive to rock stiffness. The integration of results obtained is used to guide the development plans of the complex. The results indicated that the hot spring is associated with a structure characterized by low resistivity and low shear wave velocity. The study assumes that a fault is controlling the hot water path to the surface. Besides, an IP survey was conducted to differentiate between water and clay since both are characterized by low resistivity. Based on this finding, the study suggests that the site suggested for new facilities is located near the north fence as characterized by high shear wave velocity and is considerably away from the structures controlling the water flow through the hot spring. From MASW depth slices, it appears that two conjugate faults control the geothermal system at the site. The faults are intersecting at the surface location of the hot spring.

Approbation of seismic and electrical geophysical techniques complex for solving the permafrost monitoring problems on the pile-foundation building

In the urban conditions in Salekhard city, a complex of methods, including electrical resistivity tomography (ERT), ground penetrating radar (GPR), a seismic survey on refracted waves (REF), on surface waves (MASW) and the standing waves selection, was tested on solving geocryological problems and monitor the permafrost at the building base. As a model object, a residential building on a pile foundation, built according to the principle I and equipped with a continuous geothermal monitoring system, was chosen. It has been established that the ERT, REF, and MASW methods are ineffective in the conditions of a reinforced concrete pile foundation in a grillage and a concrete floor screed with a layer of loose bulk soil under it. The best result was shown by GPR at frequencies of 150 and 400 MHz and seismic exploration with the standing wave selection. A combination of these methods is recommended for determining the upper permafrost boundary under buildings, determining the actual piles-length, the quality of their fixing, assessing the water content of soils in the area around the piles, and establishing the residual building life.

Comparing Vs profiles from MASW and downhole logging method from glacial deposits in central Illinois

Comparing Vs profiles from MASW and downhole logging method from glacial deposits in central Illinois

Combined application of electrical resistivity tomography and multi-channel analysis of surface waves methods in the tunnel detection: A case study from Kocaeli University Campus Site, Turkey

In this study, two-dimensional electrical resistivity tomography (ERT) and one-dimensional multi-channel surface waves analysis (MASW) methods conducted on the surface were used to examine the location of a creek drainage tunnel constructed for the campus road and its relationship with the surrounding geological units in the Kocaeli University campus site results are presented. As it is known, geophysical studies conducted from the surface are generally applied in terms of feasibility and to determine the geological problems in the route of tunnels before the tunnel construction. Geophysical studies revealing the tunnel and associated underground characteristics in a completed tunnel are very limited. Therefore, this study aims to describe the general character of the tunnel and its surroundings in the subsurface, with measurements made by using surface geophysical methods (ERT and MASW) over the tunnel. In the ERT studies, four different arrays were examined to resolve this problem. These are, respectively; Wenner-alpha, −beta, −gamma and Schlumberger. On the tunnel problem here, a possible model similar to the geological structure dominated by the marl layers in the region was synthetically designed with these arrays. In this study, the effectiveness of all these arrays against the problem was tested. Then, by evaluating the data collected from the field, the appropriate array testing was examined for the real problem. In the context of these studies, the results of the MASW studies conducted between 24 and 46 m of the ERT line were compared with the ERT data to reveal the geological phenomena in the tunnel and its vicinity. The resistivity values (ρ) in the 2D electrical resistivity models obtained from ERT have values of ρ > 80 Ωm in the tunnel section and ρ < 55 Ωm in the materials surrounding the tunnel. The medium-high resistivity values characterize the earthfill layer. In MASW studies, it was revealed that shear wave velocity (Vs) values in the tunnel were lower (<250 m/s) and higher (250 and 500 m/s) in the materials surrounding the tunnel. Deep below the tunnel and in the northeastern part of the field, the ground has relatively higher shear wave velocities (Vs > 400 m/s). Because of the comparison of ERT and MASW results, it was revealed that both methods showed good agreement in terms of tunnel depth and size. While the different sequences used in the ERT study generally provided successful results in identifying the tunnel, different model results were revealed in the surrounding earthfill, weathered and intact marl layers. The MASW results, on the other hand, gave more successful results than expected in determining the location of the tunnel. Because of the comparison of both methods, it has been shown that the use of the ERT and MASW methods together can provide more effective results in examining the location of buried tunnels and their relationship with the surrounding geological units.

Characterization of an earth dam in Brazil from seismic refraction tomography and multichannel analysis of surface waves

Effective methodologies to obtain information regarding the internal features in an earth dam are fundamental for rapid and technically correct decision making. Although several geophysical methods have potential applicability for investigations on dams, the contribution of seismic methods is well known, since the P and S-waves velocities can be associated with elastic modules of geotechnical interest. The study area was the Paranoá dam, the largest dam in Brazil's federal capital. We analyzed the internal structure of the dam and identified anomalies that could be associated with water saturation. We used traveltimes tomography to obtain Vp models and the MASW method to obtain Vs models. Four profiles of seismic data were acquired downstream of the dam. Borehole's information was used to corroborate with the geophysical interpretation of the profiles. The dam's abutments and the foundation ground could be identified within most models, and the velocity values obtained were mainly related to the clay material that forms the dam's massif, with higher values associated with the quartzite rocks. The rockfill material was well marked as a low velocity zone. Saturated zones were interpreted as local anomalies of high Vp/Vs ratio. An analysis of the depth range obtained within velocity models suggests that the depth of investigation from both methodologies are likely to be site specific, rather than exclusive matter of source and receiver instrumentation.

INFLUENCES OF DATA ACQUISITION AND LAYER PARAMETERS ON FUNDAMENTAL DISPERSION CURVE IN ACTIVE MULTICHANNEL ANALYSIS OF SURFACE WAVE (A-MASW) METHOD

Aktif ÇKYDA yönteminde, sığ yeraltının güvenilir bir S-dalgası hız-derinlik profilini elde etmek için en önemli aşamalarından biri, geniş frekans aralığında sürekli ve yüksek ayrımlı bir dispersiyon eğrisinin elde edilmesidir. Bu makalede, tabaka (S- ve P-dalga hızları, yoğunluk ve kalınlık) ve veri toplama (kaynak ofseti-X0, alıcı aralığı-dx ve sayısı-N, serim boyu-L=(N-1)*dx) parametrelerinin, yüzey dalga alanının temel mod dispersiyon eğrisi üzerindeki etkileri, yapay atış verilerinin analizi ile incelenmiştir. Yapay veriler, tabaka yansıma/iletim katsayısı tekniği ile hesaplanan dispersiyon eğrisi kullanılarak, her bir alıcıda harmonik mod toplama tekniği ile oluşturulmuştur. Buna göre, düşük S-dalga hızlı ara tabakalar dispersiyon eğrisinin düşük frekans bölgesinde düşük hızlara kaymasına, yüksek hızlı ara tabakalar ise, dispersiyon eğrisinin yüksek frekanslarda sürekliliğinin bozulmasına (zig-zag etkisi) ve yüksek mod etkisi yanılgısına neden olabileceği gözlenmiştir. Kaynak ofseti yüzey dalgalarının tam dalga formlarının oluşmasında etkin iken, ilk ve son alıcı arası uzaklık olan serim uzunluğunun ise, dispersiyon eğrisinin frekans bandını ve çözünürlüğünü etkilediği görülmüştür. Ayrıca, geniş alıcı aralıklarının, dispersiyon eğrisinin düşük frekans bölgesindeki güvenirliğinin arttırmasının yanında, yüksek frekans bölgesinde dalga sayısı katlanması nedeniyle dispersiyon eğrisinin sürekliliğini bozduğu görülmüştür. Sonuç olarak, farklı dalga hızlarına sahip yer modelleri için üretilen yapay veriler üzerinde yapılan analizler N

Development of Empirical Correlation between Standard Penetration Test and Shear Wave Velocity for Dahej Region

The earthquake that took place at Bhuj in 2001 acted as a wake-up call that triggered a review of the seismic risk in several areas of the nation. Seismic microzonation analysis benefits greatly from in-depth investigations of both geotechnical and geophysical conditions. This study aims to create correlations between the conventional SPT-N value and the s - wave velocity for different soil conditions in the Dahej port. For the geophysical site characterization, the shear wave velocity models were created using the MASW method and the bundle of software known as SeisImager/SW was used to perform an analysis of the test results. Moreover, the correlations are compared to the relationships established by other scientists. The suggested correlations will be beneficial for the congested areas of the vibrant area, where testing is neither practical nor cost-effective. Such empirical correlations will be used for other similar geological and geophysical site conditions when they have gone through the essential validation stages. To analyze the ground response and a hazard assessment of the study region, the obtained correlations can be used.

Imaging Subsurface Structures at Fast Eroding Coastal Areas in Northern Bengkulu Using 2D Seismic MASW Method

Imaging Subsurface Structures at Fast Eroding Coastal Areas in Northern Bengkulu Using 2D Seismic MASW Method

On the method of surface-wave tomography and perspectives for its application in engineering seismic exploration

The upper part of the seismic section is studied using refracted waves, as well as surface waves using the MASW method during engineering seismic surveys. This work is devoted to consideration of a relatively new near-surface approach, which is actively used in seismology for studying the upper mantle and deep part of the earth's crust, the method of surface wave tomography. This method is of great practical interest, since it allows to obtain 3D subsurface models and conduct remote researches; also it potentially has better spatial resolution than the widely used MASW method. Within the framework of this work, tests of the developed algorithm for surface-wave tomography using direct rays were carried out on modeled data. The performance of the algorithm was assessed and the resolution of the method was estimated. Also the optimal observation schemes were considered as well as the influence of the regularization parameter value on the inversion result. Basing on the results of the current study, it can be concluded that the method of surface-wave tomography and its realization via the developed algorithm can be effectively used to solve engineering-geological problems.

Design and Application of a Multichannel Analysis Surface Waves Acquisition System for the Pavement Layers Investigation

This study aims to design and develop a pavement non-destructive quality testing device with the MASW method. Unlike the traditional acquisition techniques that plants geophones on the pavement, the presented approach uses no-tip geophones, placed directly on the pavement surface to preserve its integrity. To proceed, a seismograph using an Arduino Due microcontroller connected to a Raspberry Pi 4 nano-computer was developed. The receivers consist of 6 4.5 Hz GD geophones connected together by a graduated tape to control the inter-trace distance and to in order to acquire data in land-streamer. The recording is triggered by a KY-038 sound sensor. The Arduino acts as an analog-to-digital converter while the Raspberry is used as a real-time data visualization and processing interface. The obtained seismic data has been processed using the Geopsy open-source software which allows the analysis and inversion of the dispersion curves. The studied system has been tested in 4 different sites. The obtained seismic VS and VP velocities as a function of the depth allowed to deduce the elastic properties of the pavement layers and to decide on their mechanical quality with the possibility of integrating the results in the road data banks.

Applied geophysics to support the cultural heritage safeguard: A quick and non-invasive method to evaluate the dynamic response of a great historical interest building

An experimental dynamic characterization was carried out through the execution of non-invasive geophysical surveys, in order to obtain useful information for planning interventions aimed at protecting the structure. In particular, HVSR and MASW methods allowed to reconstruct the subsoil seismostratigrafic structure, and HSSR and RDM techniques was employed to obtain the structure dynamic properties.It was highlighted a complex dynamic of the building, probably linked to the numerous modifications it has undergone over the centuries. A clusters analysis, carried out on the fundamental frequency values detect in the measurement sites, allowed to identify structure parts with homogeneous dynamic behaviour. Comparing the vibration frequencies of the building with the ground ones, there seems to be no possibility that soil-structure resonance phenomena may occur.

The Optimum Field Configuration for Active MASW Survey on Peat Soil

The application of the MASW method on engineering investigation required optimization of the field configuration to ensure high quality dispersion image for reasonable shear wave velocity profile estimation. The limited investigation with respect to peat soil condition has motivated the study to determine the optimum field configuration for peat soil. The challenging characteristics of peat soil including high void ratio, compressibility, water content and low shear strength further complicates the determination of optimum field configurations. The study focused on the determination of optimum field configurations for active MASW method which includes the receiver spacing, source offset, sensor frequency and sampling interval. The results obtained shows that, the optimum receiver spacing to obtain high signal to noise ratio dispersion image was 1 meter. Smaller receiver spacing causes domination of higher modes and wide bandwidth, while longer receiver spacing causes significant drop in signal to noise ratio governed by rapid energy dissipation with distance. For the source offset, the distance of half the total spread length (X1 = L/2) provides the best resolution and minimised near-field and far-field effect. While, 4.5 Hz sensor frequency and sampling interval between 100 to 250 s provides sufficient low frequencies for deeper depth investigation and denser data. Overall, the influence of receiver spacing, source offset and sensor frequency on the dispersion image resolution was significant.

Comparison of Dispersion Image Resolution Acquired Using Multichannel Analysis of Surface Waves with Different Source Energy and Stacking

Active MASW method is a promising method to determine the stiffness characteristics of the subsurface strata. The accumulation energy to obtain high-resolution dispersion image depends largely on the energy generated from the active source. From the results obtained, the influence of different source energy, source plate and number of stacking on the dispersion image resolution were significant. Heavier source weight (e.g.7 kg sledgehammer) produced highamplitude energy band and provides even lower frequencies. However, if lighter source weight (e.g. small steel hammer) was used, it needs to be coupled with rubber plate to increase the low frequency content, thus generate deeper depth of investigation. Finally, the use of rubber plate and stacking increased the resolution of the dispersion image especially at lower frequencies by significantly suppressing the ambient noise.

Integrated Analysis of Microtremor Horizontal to Vertical Spectral Ratio, Surface Waves Dispersion Curve, and Seismic Refraction Tomography to Estimate Weathered Layer Thickness and Seismic Vulnerability: Case Study Kalirejo Village, Kokap Sub-District, Kulon Progo Regency

Subduction of Indo-Australia plate to Eurasia plate and locally active fault nearby Kulon Progo play as major source for earthquake events. After effect due to earthquake has different level of damage which depend on the magnitude and site characteristics. The horizontal-to-vertical spectral ratio (HVSR) passive seismic method is being used drastically to help in mapping the level of site vulnerability to earthquake event. HVSR analysis results help us acquire some physical values including weathered layer thickness where Vs 30 reference came from surface waves dispersion curve analysis of the MASW method as it is used as a parameter in calculating thickness value. Seismic refraction tomography is used to create subsurface model thus we may see the extent of underlying layer and its implication to earthquake event.Data measurements distribution are scattered in Kalirejo Village with the total of 63 passive seismic data, 33 MASW data, and 7 lines of seismic refraction acquisition. Some data show inadequate quality to be taken into further processing step, so data sorting activity should be carefully done. As a result, 21 of 63 passive seismic data are considered adequate to represent site physical values. Dominant frequency values ranging from 2 to 20 Hz, amplification factor varies between 1.5-12.5, and seismic vulnerability indices varies between 0.3-20. Surface waves dispersion curve inversion results are Vs 30 values ranging from 350 m/s to 980 m/s and seismic refraction tomography model shows Vp model with velocity values ranging from 0.2 to 3.2 km/s.

Estimating Near-Surface Shear-Wave-Velocity Structures Via Multichannel Analysis of Rayleigh and Love Waves: An Experiment at the Boise Hydrogeophysical Research Site

Surface-wave analysis has been widely used for near-surface geophysical and geotechnical studies by using the dispersive characteristic of surface waves (Rayleigh or Love waves) to determine subsurface model parameters. Unlike Rayleigh waves, the dispersive nature of Love waves is independent of P-wave velocity in 1D models, which makes Love-wave dispersion curve interpretation simpler than Rayleigh waves. This reduces the degree of nonuniqueness leading to more stable inversion of Love-wave dispersion curves. To estimate the near-surface shear-wave velocities (Vs) using multichannel analysis of Rayleigh (MASW) and Love waves (MALW) for hydrologic characterization, we conducted an experiment at the Boise Hydrogeophysical Research Site (BHRS, an experimental well field located near Boise, Idaho, USA). We constructed the pseudo-3D velocity structures at the BHRS using both the MASW and MALW methods and compared the results to borehole measurements. We used the 3D Vs distribution to identify and resolve the extent of a relatively low-velocity anomaly caused by a sand channel. The Vs structure and anomaly boundaries were delineated at the meter scale and confirmed by the ground-penetrating radar surveys. The differences in shear-wave velocity determined by MASW, MALW and borehole measurements were discussed and interpreted to reflect the near-surface anisotropy associated with the hydrologic characteristics at the BHRS. Our results demonstrated that the combination of MALW and MASW can be a powerful tool for near-surface characterization.

Approximation of Shear Wave Velocity Using MASW Method for Seismic Hazard Mitigation: A Preliminary Study of Banda Aceh City Indonesia

Earthquake 9.1 SR happened in the Aceh Province Indonesia that followed tsunami on December 2004. After this event, the development of infrastructures in Banda Aceh city has shown rapidly progress. Therefore, learning of the experience of this natural event that has caused many casualties and infrastructures, the Banda Aceh city has been being taken initiative as a city that is friendly of disasters. The research objective analysed of influence sedimentation behaviour at buildings. The shear wave velocity parameters using MASW method were used for sediment characteristic assessment. The sediment characteristics are very soft, soft, dense and very dense that it’s have level different of shaking, respectively. The detail of 1D profiles of shear wave velocity have obtained. In this case, we analysed VS30 parameters of eleven locations of all measurements at the Ulee Kareng Sub District, Banda Aceh city. The ground shaking level of sediment layer depend of sedimentation characteristics. The sediment characteristic of Ulee Kareng Sub District, Banda Aceh has shown medium dense and soft soil.

Geophysical site assessment in karst terrain: A case study from southwestern Missouri

A 110 acre study site in karst terrain in southwestern Missouri was investigated to assess suitability for landfill expansion. ERT, MASW and core hole data were acquired on the site with the objectives of identifying any karst features that could potentially pose a threat to an overlying landfill, mapping variable depth to the top of rock, and mapping the probable flow pathway(s) of groundwater from the site to both a proximal spring and a proximal creek. Top of rock was readily mapped on the acquired ERT data, except in those areas where shallow bedrock was anomalously moist, such as beneath drainage ditches and surface flow pathways. In areas where bedrock was anomalously moist, depth to top of rock was more reliably estimated using the MASW method. Karst features that could affect the stability of an overlying landfill were not imaged on the geophysical data. Dye testing was performed to establish connectivity between the site and the proximal spring. Probable flow pathways from the site to the spring and the creek were identified.