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Bu çalışma, sismisitesi yüksek, aynı zamanda jeomorfolojik yapısı ve yüksek yağış rejimi ile heyelan probleminin sıklıkla gündeme geldiği bölgelerden biri olan Sakarya ilinin Karapürçek ilçesinde meydana gelmiş bir kütle hareketinin bütünleşik jeofizik yöntemler ile modellenmesini amaçlamıştır. Bu amaç doğrultusunda heyelan yüzeyinde farklı fiziksel özelliklere duyarlı iki boyutlu (2B) elektik rezistivite tomografisi (ERT), aktif yüzey dalgaları analizi (MASW) ve mikrotremör (HVSR) yöntemleri uygulanmıştır. Jeofizik kesitler ile heyelan içyapısının gerçeğe daha yakın modellenebilmesi için jeolojik zemin sondajlarına da başvurulmuştur. Gerçekleştirilen bütünleşik çalışmalarda, yüksek özdirence ve kayma dalgası hızına (Vs) sahip heterojen yapıda kırıklı-çatlaklı arkozik kumtaşı malzemesinin alışagelmiş kütle hareketi modellerinin aksine düşük özdirence ve Vs hızına sahip kiltaşı üzerinde hareket ettiği belirlenmiştir. Bu karakterizasyon mikrotremörden elde edilen doruk genlik frekans değerlerinin düşük frekanslara doğru hareketi ile de desteklenmiştir. Ayrıca alt kotlara doğru yeni kayma düzlemleri ile gerçekleşen ilerleyişin peneplen vadi sırtında bir rotasyona uğradığı ve farklı yönde bir kayma düzlemine evrildiği tespit edilmiştir. Elde edilen bu sonuçlar çalışma alanındaki kütle hareketini tanımlayan basitleştirilmiş bir şematik diyagram üzerinde de verilmiştir. Son olarak heyelan karakterizasyonu kapsamında gerçekleştirilen bu gibi çalışmaların kütle hareketini önlemedeki rolü ve farklı disiplinlere sağladığı katkı ortaya konmuştur.

Bengkulu Province, including North Bengkulu and Lebong, is located in the subduction zone of the Indo-Australian and Eurasian plates, which makes the region prone to earthquakes. This research focuses on earthquake disaster mitigation in the Lemeu area, Uram Jaya District, and Lebong Regency. It identifies areas prone to earthquake shaking based on Vs stratigraphy, Vs30 distribution, and soil site class. The Vs value was measured directly using the Multichannel Analysis of Surface Wave (MASW) method for three passes. Each track has four stations, so there are 12 data collection stations. The station point is the center point of a series of 24 geophones. Each geophone has a recording time of 512 ms and a sampling rate time of 125 ms to obtain 4096 data for each geophone. The measurement data was processed using WINMASW 5.0 professional software to produce a 1D profile. From the stratigraphic Vs, Vs30 is calculated and used to determine the site class, and then a distribution map is made. The results show that this area consists of site classes D, C and B. Medium soil with a value range of 175 ≤ Vs30 ≤ 350, hard soil with a value range of 350 ≤ Vs30 ≤ 750 and soft rock with a value range of 750 ≤ Vs30 ≤ 1500. Of the 12 measurement points, 2 locations have relatively shallow Vs30 values, namely at points 4 and 11. This location has Vs30 values ranging from 221 - 258 m/s, so around this point, there is likely a high potential for building damage in the event of an earthquake.

A well-developed soil structure is crucial for a fertile soil and rules its influence on the ecosystem. Slight variations in the way soil components are organized and connected can greatly impact the soil mechanical and hydraulic characteristics. However, these features are challenging to measure at a scale that is relevant for agricultural management. In this study, we assess the capability of two seismic geophysical methods, i.e. Seismic Refraction Tomography and Multichannel Analysis of Surface Waves, to monitor the effects of compaction on agricultural bare soil. The purpose is to highlight the different mechanical response caused both by soil plastic deformation and soil water distribution due to increasing compaction. Results demonstrate that both geophysical techniques provide sufficient information to capture the effects of soil compaction and distinguish its significance, while traditional direct measurements, being punctual, lack sufficient spatial coverage. P-wave velocities carry a strong imprint of soil compaction, provided by seismic refraction, incorporating the information given by the multiphase medium in its entirety. On the other hand, S-wave velocity derived from Surface Waves discriminates the effect of solid matrix structure. This work, moreover, aims to pave the way for seismic methods to spatially characterize compaction at field scale, illustrating its potential and suggesting possible developments.

The site characterization process is vital for the engineering structures and earthworks. In the current study, a Multi-Channel Analysis of Surface Waves (MASW) was carried out in western Riyadh City, Saudi Arabia. This aimed to determine subsurface geology, material stiffness, and potential weak zones approximately down to a depth of 30 m, and to propose the suitable seismic site characterization for precise foundation design. A total of 30 MASW lines were executed utilizing the Geode digital seismograph equipped with a 24-geophone array of 4.5 Hz. The data acquisition, processing, and inversion were meticulously calibrated to derive shear velocities representing subsurface geological conditions. The Vs30 map, based on estimated values ranging from 443.71 m/s to 639.78 m/s for soil, was prepared for the area. The results of the 1D and 2D Vs profiles tinted small Vs values at shallow depths. The resulting geological model is composed of sand, gravel, moderately weathered limestone, and hard limestone sequence. Analysis of shear wave velocities shows variations, indicating low shear velocity (representing sediments or rocks of low stiffness) juxtaposed with higher velocity layers (indicating rocks of higher stiffness) at depths greater than 10 m. This could imply the presence of a cavity or weak zone. The topmost shear wave velocity zone indicated materials with low Vs values (ranging from 180 m/s to 360 m/s), predominantly associated with stiff materials such as silty sand, gravel, and sandy deposits. The subsequent zone, with 3 to about 10 m depth, was characterized by medium to very dense soil with shear wave velocity values ranging from 360 m/s to 760 m/s, attributed to layers of silty clay and silty sand. At approximately 12 m, a high shear velocity layer (ranging from 760 m/s to 1,500 m/s) was identified, extending to a maximum depth of 22 m, potentially indicative of less weathered or fractured bedrock associated with limestone. While the deepest layer, with very high shear velocity (exceeding 1,500 m/s) beyond 22 m, indicated bedrock associated with hard limestone. The average Shear-wave velocity of soil for the whole study area (Vs30 = 551.2 m/s) suggests that the site can be classified as Class C (Very Dense Soil and Soft Rock) according to the National Earthquake Hazard Reeducation Program NEHRP (National earthquake hazards reduction program, 2001). These results will support, to a great extent, the design of engineering structures in the area of study.

Seismic surface and body wave analyses are powerful tools for the geotechnical characterization of sites. The use of landstreamers facilitates the acquisition of dense data sets over large areas. However, efficient processing workflows are needed to estimate 3D velocity models from these massive data sets. For surface wave analysis, the manual picking of dispersion curves (DCs) of large data sets is very time-consuming, whereas the accuracy can be biased by operator choices. We apply a semi-automatic workflow for the analysis, processing, and interpretation of a large-scale landstreamer data set acquired for engineering purposes in the Middle East. The workflow involves the application of a validated automatic DC picking algorithm, and the transformation of the DCs into S- and P-wave velocity models through the wavelength-depth technique. The method has a high level of automation, is data driven and does not require extensive data inversion. Another remarkable benefit is that the auto-picking is more than 1,000 times more efficient than standard manual picking and the estimated velocities are in good agreement with available geotechnical and geophysical information. We conclude that the semi-automatic approach may represent a fast and straightforward method suitable for both research and industrial projects, thus enhancing further collaborations and developments.

Abstract In coastal alluvial plains, the variability of sedimentary inputs, tectonic and eustatism causes a complex subsurface geology which influences the position of fresh/saltwater interface. Furthermore, in these areas densely populated, the over-pumping of freshwater, coupled with the climate change events, promotes the landward migration of freshwater/saltwater boundary. This research illustrates the ability of geophysical tools to recognize the presence of salt/brackish water at Volturno Coastal Plain, Southern Italy. This area is characterized by a peculiar geological setting, due to the proximity at Somma–Vesuvio and Campi Flegrei volcanic areas, which profoundly influences the circulation of groundwater. The subsurface is mainly characterized by: (i) two denser layers located at − 10 m and − 20 m depth which in part prevents the vertical migration of groundwater, (ii) facies heteropy that facilitates the hydraulic connection between the different geological bodies, (iii) a discontinuous Campanian Ignimbrite deposits which favor the hydraulic connection between deeper and shallower aquifers. In this geological framework, 2D-ERT and 3D-ERT integrated with Downhole, Multichannel Analysis of Surface Waves and boreholes made possible to recognize the presence of two main zones with salt and brackish waters, respectively. The first zone, characterized by very low resistivity (≤ 1 Ωm) typical of salt water, stretches 1.5 km inland from the coast. The second zone, with a resistivity between 2 and 5 Ωm typical of brackish water, continues for other 3 km inland. This knowledge is useful for the engagement of all stakeholders (farmers, ranchers and policy makers) in the sustainable use of fresh water and for making water management plan operational tools.

Philippines is one of the most seismically active countries in Southeast Asia and records at least 20 earthquakes per day according to the PHIVOLCS. Vs30 is defined as the shear wave velocity of the upper 30-meter subsurface profile which is an important seismic parameter to determine the dynamic behavior of soils or rocks. This research aims to determine the Vs30 of three sites in Metro Manila using two methods Geotechnical Investigation(GI) and Geophysical Investigation(GPI) by Multichannel Analysis of Surface Waves (MASW) method and compare their results. The data used for GI are SPT N-values for soils and Rock Quality Designation. Conversely, a seismic survey using the MASW method was conducted along the three sites and Vs30 was determined based on the processed seismic data from Geogiga software. The results of the methods were compared in terms of the ratio between the Vs30 difference from geotechnical investigation and geophysical investigation with the calculated range based on the NEHRP classification table. The calculated ratios showed 43.68% for MNHS, 6.44% for BES, while 48.16% for VFMHS. Comparison of methods showed that ratio between Vs30-difference from GI and GPI with the calculated range based on the NEHRP was found to be acceptable (≤1.0) for all sites. Moreover, the seismic soil classification based on the NEHRP was found to be consistent for both methods.

Bengkulu City has a high liquefaction rate, both geologically and geophysically. This is because Bengkulu City consists of rocks in the form of sand, silt, mud, clay, coral fragments and gravel in alluvial areas (Qa) and floodplains. Terrace formation (Qat). This study aims to analyze liquefaction potential using seismic waves in Bengkulu City, resulting in a layer profile (Vs) obtained from the Vs30 soil of Bengkulu City and a classification of areas with liquefaction potential. This study was conducted using a PASI 16S-24P seismograph, a set of seismic equipment used in the study area, which obtained Vs profiles derived from 24 geophones 4 m and 8 m away from each study location. Then, the RMS error and standard deviation values were generated. The result of MASW analysis data describes the Vs and Vs30 profiles in the Bengkulu City subsoil that can be classified into soil zones. Soil results at the study site show different site classes, namely B, C, D and E. Liquefaction potential can be analyzed with Vs profiles. It shows the existence of different layers in the Bengkulu city area. It can be seen that Bengkulu City is dominated by sand and gravel, causing very high liquefaction, especially in the Surabaya area, where the Vs and Vs30 soil values have soft soil values with sensitivity values of 134.0 to 171.0 m/s. Soil classification is highly sensitive to liquefaction. The study areas of Lempuing and Rawa Makmur sub-districts generally show medium liquefaction potential, and the Teluk Sepang sub-district area shows low liquefaction potential.

A subsurface investigation was conducted to assess the suitability of a site for potential tunnel construction, focusing on the determination of shear wave velocities (Vs) in subsurface materials. This study employed three distinct methods to analyze Vs in weathered soft rock: drilling mechanism, multichannel analysis of surface waves (MASW), and microtremor array measurement (MAM). Through the utilization of MASW and MAM, empirical relationships were established, enabling the determination of Vs based solely on soil type and depth, offering a practical alternative to the limitations of SPT N-Value, particularly when exceeding 50 blows. The comparison of Vs values obtained from these methods revealed a close alignment between empirical techniques and MASW/MAM, which proved to be cost-effective and an efficient alternative to drilling for comprehensive underground structure assessments. The reliability of MASW was further underscored through its comparison with existing empirical methods. Moreover, the empirical approach demonstrated its efficacy in predicting velocities in weathered soft rock within the Central Himalayan region of Nepal, thus enhancing the feasibility study of underground structures. Lastly, this study proposed a Vs-Depth correlation specifically tailored for highly weathered meta-sandstone bedrock resulting in clay and sandy soils.

The seismicity in the SE Iberian Peninsula is distributed parallel to the coast in a well-developed strike-slip fracture system known as the Eastern Betic Shear Zone (EBSZ). This work focuses on the characterization of the shallow subsurface structure of the Algezares-Casas Nuevas Fault, within the Carrascoy Fault System of the EBSZ. The Carrascoy Fault borders the Guadalentín Depression to the south, which is a densely populated area with extensive agricultural activity. Therefore, this faults system represents a seismic hazard with significant social and economic implications. We have constructed two velocity-depth models based on P-wave tomography and Multichannel Analysis of Surface Waves (MASW) acquired from seismic reflection data. The resulting velocity models have allowed us to interpret the first ~250m depth and have revealed: i) the thickness of the critical zone; ii) the geometry of the Algezares-Casas Nuevas Fault; iii) the depth of the Messinian/Tortonian contact and iv) the presence of blind thrusts and damage zones under the Guadalentín Depression. Our results have also helped us to estimate an apparent vertical slip rate of 0.66±0.06m/ky for the Algezares-Casas Nuevas Fault since 209.1±6.2ka. Our results provide a methodological and backflow protocol to study the shallow subsurface of active faults, complementing previous geological models based on paleoseismological trenches, and can be used to improve the seismic hazard assessment of tectonically active regions around the world.

Soil tests and Multichannel Analysis of Surface Waves (MASW) data were conducted in Hatsalatladi village, Botswana, to investigate the occurrence of ground fissures within the village and to identify the likely causes of the fissures and their depth extent. The MASW data were collected to gain insights into the variation of shear wave velocity with depth. The dataset shows that the shear wave velocity ranged from 150 m/s – 500 m/s, with Poisson's ratios ranging from 0.02 to 0.25. A low-velocity zone (LVZ) was observed in the upper 5 m of the subsurface with velocities ranging from 200 m/s to 350 m/s.The soil plasticity was measured through the plastic and liquid Atterberg tests. Atterberg limits measurements obtained from the three survey sites show that the plastic index of the soil samples collected from depths of 1 m fall within the 10–20% range. Specifically, the Filled Crack survey site had a plastic index of 16%, while the Abandoned House and Bridge sites had 18.7% and 13.5%, respectively. Soil samples from Filled Crack and Abandoned House site revealed a linear shrinkage of 6.4%, while the Bridge site soil sample had a linear shrinkage of 2.9%. The sieve analysis test results are also presented.

El estado de Uttarakhand en la India se encuentra en una zona de alta actividad sísmica, por lo que se han seguido criterios de diseño resistentes a los terremotos para las principales prácticas de construcción en esta región. Una de las principales entradas para el diseño resistente a los terremotos es la velocidad media de la onda de corte (VS ) a 30 m de profundidad. En el presente trabajo, en veintiséis sitios diferentes, la técnica de la relación espectral horizontal a vertical (HVSR) y el análisis multicanal de onda de superficie (MASW) se utiliza para el análisis conjunto para obtener un modelo de velocidad unidimensional que soporta tanto la curva de espectro de HV como la curva de dispersión obtenida de los métodos HVSR y MASW, respectivamente. Los perfiles de onda de corte obtenidos en varios sitios se comparan con los datos de registro de perforación obtenidos de la perforación y muestra claramente que los Vs para la misma formación tienen una fuerte dependencia de la profundidad en la que ocurrió. Se han utilizado datos de veinticuatro perfiles de onda de corte para preparar una relación de regresión lineal de Vs para diferentes formaciones litológicas con res- pecto a su profundidad de ocurrencia. El error cuadrático medio obtenido a partir de la relación desarrollada para varias litologías muestra claramente que los resultados están bastante bien dentro del rango de aceptación. Las relaciones desarrolladas han sido validadas adicionalmente por el cálculo de perfil Vs de los datos de registro de perforación obtenidos en dos nuevos sitios de ubicación que no están incluidos en el conjunto de datos utilizado para la preparación de relaciones de regresión. Una comparación de dos secciones de velocidad muestra claramente que el perfil de velocidad calculado a partir de la relación de regresión coincide estrechamente con el obtenido de la encuesta sísmica y por lo tanto se establece la eficacia de la relación de regresión desarrollada para su implementación práctica. Esta relación desarrollada permite la clasificación del tipo de suelo para fines de zonificación. doi: https://doi.org/10.22201/igeof.00167169p.2022.61.3.2200

One hundred seventy geotechnical boreholes, two geo-seismic profiles of multichannel analyses of surface waves (MASW), and two geoelectrical cross-sections of electrical resistivity tomography (ERT) were carried out in the historical Diriyah urban zone. The borehole samples were analyzed for the geotechnical parameters of the standard penetration test (SPT N-value), the rock quality designation (RQD), and compressive strength (CS). Moreover, P- and S-wave velocities have been calculated. The measured SPT N-value has been corrected to amend the N60 parameter. According to the corrected N60, type, lithological, and soil profiles were divided into five distinct subsurface layers. It is indicated, for all recorded depths, these sediments become denser with depth where the values of N60 increase from 5 to 88 downward. According to grain size distribution, the major part of soil sites is composed of sand and varies from low to medium compressibility. The estimated RQD values range from 5 to 100 indicating rocks with significant variations in their geotechnical and physio-chemical characteristics. Furthermore, the compressive strength varies widely between 152.3 and 1,104.2 kg/cm2, which represents diverse geodynamic behavior under civil engineering constructions. Besides, the range of soil stiffness is indicated by the Shear-wave velocity (Vs) for soil layers, which varies from 171.3 to 456.2 m/s. According to the findings of the MASW profiles, the shear wave velocity is shown to be decreasing in MASW profile 1 between depths of 8 and 14 m, where the values range from 1,000 to 1,500 m/s, indicating a weak zone filled with secondary materials. But line 2 shows how the shear wave velocity decreased from depths of 5 m–11 m, where values ranged from 1,000 to 1,500 m/s, thus indicating a weak zone. The low resistivity zones in ERT cross-sections, which are found at the same depths in MASW profiles, are well associated with these findings. It can be concluded that there are a number of weak zones with varying depths, shapes, and dimensions found in the historical Diriyah urban zone’s near-surface deposits that civil engineers, urban planners, and urban developers should consider before undertaking any construction or developmental work involving civil engineering.

The characterization of a groundwater body involves the construction of a conceptual model that constitutes the base knowledge for monitoring programs, hydrogeological risk assessment, and correct management of water resources. In particular, a detailed geological and geophysical approach was applied to define the alluvial Caronia Groundwater Body (CGWB) and to reconstruct a hydrogeological flow model. The analysis of the CGWB, located in north-eastern Sicily, was initially approached through a reanalysis of previous stratigraphic (boreholes) and geophysical (vertical electrical soundings and seismic refraction profiles) data, subsequently integrated by new seismic acquisitions, such as Multichannel Analysis of Surface Waves (MASW) and horizontal-to-vertical seismic ratio (HVSR). The analysis and reinterpretation of geoelectrical data allowed the construction of a preliminary 3D resistivity model. This initial modeling was subsequently integrated by a geophysical data campaign in order to define the depth of the bottom of the shallow CGWB and the thickness of alluvial deposits. Finally, a preliminary mathematical model flow was generated in order to reconstruct the dynamics of underground water. The results show that integration of multidisciplinary data represent an indispensable tool for the characterization of complex physical systems.

Natural disasters such as debris flow caused by earthquakes seriously threaten the local infrastructure and economy, as well as the lives of people in the area. As the material source of debris flow, it has significance to accurately and effectively study the underground structure of the landslide to prevent debris flow disasters. A landslide has a complex structural system, and its underground characteristics play an important role in its stability. The early identification of fracture surfaces and unstable bodies, and assessment of potential hazards are essential for prevention and protection. The research object of this paper is a landslide that occurred in Yige Village, Xianshui Town, Daofu County, which is on the Xianshui River Earthquake Zone, an area subject to frequent earthquakes. In western Sichuan, the frequent occurrence of landslides has caused considerable economic losses. Developing methods for efficient and accurate risk assessment is a top priority. The Daofu landslide is a typical example of a landslide directly threatening the road below and forming a debris flow channel. The lithology is composed of Jurassic sedimentary rocks, such as marl and clay, covered by limestone. In this study, we combined traditional methods (drilling and field investigation) with two geophysical techniques, multichannel analysis of surface waves (MASW) and electrical resistivity tomography (ERT) to effectively determine the electrical characteristics, velocity characteristics and spatial structure of the landslide. It is found that the buried depth of the sliding surface of the landslide is about 16–20 m. The sliding body above the sliding surface forms a low velocity and low resistivity Quaternary cover. The rock mass below the sliding surface is Triassic Zhuwo Formation sandstone and slate with high velocity and high resistivity. According to comprehensive analysis, the landslide lacks sufficient stability under rainstorm. Our study shows that the use of MASW and ERT can quickly and effectively characterize the subsurface of landslides to assess landslide risk and prevent debris flow hazards.

Shear-wave velocity (Vs) of soils in Nakhon Nayok City, Central Thailand were determined using the Multi-Channel Analysis of Surface Wave technique. The Vs. of 35 tested sites were weighted average to 30 m depth based on the National Earthquake Hazards Reduction Program (NEHRP) criteria, which revealed NEHRP site classes C, D, and E within the study area. Soil class C was found in the north of the city. Moreover, most of the residential area of Nakhon Nayok City is positioned on soil classes D and E. The soil in the area of study has an amplification value ranging from 1.4 to 3.9. The central and southwestern parts of the city, which mainly consist of soft sediments, have a higher amplification value than that in the northern part, which mainly consists of coarse grain soils of colluvial deposits. Based on the NEHRP and amplification value, the Nakhon Nayok City area will experience some effect from ground shaking from nearby and far away earthquake seismic sources.

We applied active-source seismic method for the interpretation of elastic parameters in tailings facilities which is essential for evaluating stability and seismic response. The methodology uses different analysis methods on the same dataset, i.e., conventional seismic refraction (SR) to determine compressional-wave velocity (Vp) and multichannel analysis of surface wave (MASW) to estimate shear-wave velocity (Vs). Seismic velocities in conjunction with tailings physics approach revealed interpretable data in terms of elastic parameters and hydrogeological conditions. The results determined the empirical linear relationships between Vp and Vs that are particular to an unconsolidated media such as tailings and showed that variability of hydrogeological conditions influences the elastic seismic response (Vp and Vs) and the elastic parameters. The analysis of the elastic parameters identified the state condition of the tailings at the time of the survey. The Bulk modulus K that relates the change in hydrostatic stress to the volumetric strain was predominant between 1.0−2.0 GPa. The Young’s modulus E in the tailings media was in the low range of 0.15−0.23 GPa. Poisson’s ratio values in all sections were in the upper limit in the range of 0.37−0.49, meaning that the tailings media is highly susceptible to transverse deformation under axial compression.

Los objetivos principales de esta investigación fueron determinar la demanda sísmica así como definir la microzonificación sísmica en el sector urbano de la ciudad de León, este sector tiene alrededor de173,866 Habitantes, este es el número de beneficiados directos con la información producida en esta investigación. En esta investigación utilizamos medición de vibración ambiental (MHVSR), así como medición de ondas superficiales con el método activo MASW. Las funciones de transferencia empíricas(FTE) mostraron que los suelos del área vibran con tres modos, los cuales varían su periodo de vibración entre los valores To1=0.049 a 0.160 s, To2=0.161 a0.330 s y To3=0.331 a 0.969 s. Además, basado en los resultados de Vs30 y en el RNC-07 los suelos del área pueden clasificarse como suelos firmes o suelo moderadamente blando o como tipo II y III, respectivamente. Los resultados de esta investigación serán utilizados con fines de fortalecer la mitigación de desastres contra terremotos en esta ciudad al ser incluidos en el reglamento nacional de construcción nicaragüense.

In the municipality of Enna, 80 HVSR measurements were performed, and some of these were combined with MASW seismic measurements, which made it possible to constrain the data inversion and obtain significant shear wave velocity models. A reconstruction of the depth of the seismic bedrock was performed for the whole territory, showing different depths for the higher and lower areas, as evidenced also by the Vseq parameter map. The frequency peaks identified in the H/V curve were analyzed through a cluster analysis algorithm to evaluate similarities that allow these peaks to be divided according to their stratigraphic origin. A non-hierarchical analysis algorithm modified in such a way as to avoid any a priori choice that could influence the partition has been used. The cluster analysis made it possible to divide the frequency peaks into five groupings, each of which was then associated with a seismic discontinuity, according to the geological contacts expected in the subsoil. Finally, the inversion of the data made it possible to reconstruct the geometries of these geological contact surfaces and to reconstruct a 3D model of the subsoil, which agrees well with the surface geology of the area.

The most valid way to determine the soil amplification is to use the analysis of strong ground motion records. The Earthquake Observation Station located in Ankara AFAD campus was established in 2014. There are many official institutions such as Ankara Bilkent City Hospital, Ministry of Health, Ministry of Agriculture and Forestry, and Ministry of Trade within the working area. Since the earthquake station was established, 22 earthquake records have been registered. Multichannel analysis of surface waves (MASW) was measured to calculate the average shear wave velocity of the upper 30 and 50 meters of the soil where the station was located. 14 earthquake records of different magnitudes and distances occurring in different fault zones recorded by the station were interpreted using the horizontal / vertical ratio technique according to the single station method, and the amplification factor and dominant vibration frequency of the soil were calculated. Apart from the earthquake records, 4 hours of microtremor measurements were made with the CMG-6TD broadband seismometer, and the measurements were evaluated according to the single station method and the horizontal / vertical spectral ratio technique. The results of MASW, microtremor and earthquake records were compared, and the dynamic properties of soil were studied. According to the results obtained from the analysis of earthquake and microtremor records, it has been observed that the amplification factor and predominant frequencies are very close to each other, compatible to the soil class calculated by using the shear wave velocity.

In this paper, we present the work carried out to characterize the spatial variability of seismic site response related to local soil conditions in the city of Milan and its surroundings, an area with ∼3 million inhabitants and a high density of industrial facilities. The area is located at the northwestern end of the Po Plain, a large and deep sedimentary basin in northern Italy. An urban-scale seismo-stratigraphic model is developed based on new passive and active seismic data, supported by the available geological data and stratigraphic information from shallow and deep vertical wells. In particular, 33 single-station and 4 ambient-vibration array measurements are acquired, together with 4 active multichannel analyses of surface waves (MAWS). To estimate the resonant frequencies of the sediments, the horizontal to vertical spectral ratio technique (HVSR) is applied to the ambient-vibration recordings, whereas to determine the Rayleigh-wave dispersion curves from the passive array, the data are analysed using the conventional frequency-wavenumber, the modified spatial autocorrelation and the extended spatial autocorrelation (ESAC) techniques. The array data are used to determine the local shear wave velocity profiles, VS, via joint inversion of the Rayleigh-wave dispersion and ellipticity curves deduced from the HVSR. The results from HVSR show three main bands of amplified frequencies, the first in the range 0.17–0.23 Hz, the second from 0.45 to 0.65 Hz and the third from 3 to 8 Hz. A decreasing trend of the main peaks is observed from the northern to the southern part of the city, allowing us to hypothesize a progressive deepening of the relative regional chrono-stratigraphic unconformities. The passive ambient noise array and MASW highlight the dispersion of the fundamental mode of the Rayleigh-wave in the range 0.4–30 Hz, enabling to obtain detailed Vs. profiles with depth down to about 1.8 km. The seismo-stratigraphic model is used as input for 1D numerical modelling assuming linear soil conditions. The theoretical 1D transfer functions are compared to the HVSR curves evaluated from both ambient noise signals and earthquake waveforms recorded by the IV. MILN station in the last 10 years.

The Athenet network is the network of the Seismological Laboratory of the National and Kapodistrian University of Athens. We present the geophysical investigation that has been carried out at six seismological stations of the Athenet network for their site characterization. More specifically, at the location of each seismological station, four geophysical methods have been carried out: Seismic Refraction Tomography (SRT), Multichannel Analysis of Surface Waves (MASW), the Horizontal to Vertical Spectral Ratio (HVSR) technique, and Electrical Resistivity Tomography (ERT). The applied geophysical survey provided important information regarding the site characterization at the selected seismological stations, including key parameters such as the fundamental frequency fo, the shear-wave velocity VS, the average shear-wave velocity for the upper 30 m depth (VS30), the seismic bedrock depth, the soil type, and the subsurface geology. Moreover, selected elastic moduli (Poisson’s ratio, shear, bulk, and Young moduli) have been calculated. The site characterization information contributes to the determination of the amplification factors for each site that can lead to more accurate calculation of Peak Ground Acceleration (PGA) or Peak Ground Velocity (PGV) and, therefore, trustworthy Probabilistic and Stochastic Seismic Hazard Assessments. The derived fundamental frequency for the seismological stations of VILL, LOUT, THAL, and EPID have been determined to be equal to 10.4, 2.7, 1.4, and 7.1 Hz and their amplification factors to be 1.9, 3.1, 1.7, and 2.6, respectively. For stations MDRA and ATAL, these parameters could not be determined.

A depth camera was used to record the spherical cavity which occurred during blasting in clay soil. For this purpose, the integration of the Global Navigation Satellite System (GNSS) method was applied in addition to the depth camera and the laser, to determine the resulting spherical cavity. The expanded spherical cavity, formed after the blasting of the explosive charge in the bottom of the borehole, was measured by a depth camera-laser system. The GNSS measurement method was instrumental for obtaining the coordinates of the borehole. The Multichannel Analysis of Surface Waves (MASW) measurement method was also used during the study. Shear wave velocities (VS) were calculated using MASW method to evaluate the dynamic properties of the clay soil along the in-situ profiles. The results obtained in this way, showed that there was an increase in the stiffness of the surrounding clay soil after blasting. The main objective of the study was to determine the resulting shapes and volume of the occurred cavities. For a more detailed graphical interpretation, an application was developed, which calculates the coordinates, shape and volumes of the formed spherical cavity.

Preliminary investigation of subsurface properties by geophysical methods were carried out over the construction site of the 40 meters Thai National Radio Telescope (TNRT) facility planning by National Astronomical Research Institute of Thailand (NARIT) in the Huai Hong Khrai Royal Development Study Center, Doi Saket, Chiang Mai, Thailand. Multichannel analysis of surface waves (MASW) and electrical resistivity tomography (ERT) were utilized in mapping of Vs distribution to obtain information on ground stiffness and other supporting information on subsurface electrical resistivity, respectively. Results from data analysis showed that the topsoil was very dense with thickness irregularly varied from 5 meters to10 meters overlying the bedrock with high variation in stiffness caused by the different degrees of weathering. The information obtained led to the conclusion that the proposed TNRT facility construction site is in the category of site class B of which the ground stability is moderate and less vulnerable to earthquake damages.

The objective of this study is to map a sedimentary layer overlying volcanic basement in Mae On area, Chiang Mai, Thailand. Seismic reflection, multichannel analysis of surface waves and electrical resistivity surveys were conducted to provide additional supporting information in the shallow part of subsurface geometry. The deeper part information is evaluated from the previous magnetic and gravity anomaly maps. The interpretation from seismic reflection is used to constrain gravity forward modeling to obtain a pseudo-geological model. The final model presents that there are a thin Quaternary sediment layer with low electrical resistivity and seismic velocity, overlies volcanic basement with high electrical resistivity and high seismic velocities. The volcanic basement can be recognized as a heterogeneous body with horizontally characteristic layers of volcanic flows based on seismic reflection profiles. The volcanic basement underneath the sediment layer shows a high anomaly on gravity and magnetic maps.

Conventional 2D electrical resistivity tomography (ERT) data were acquired along 16 parallel traverses spaced at 6.1 m (20 ft) intervals across a karst sinkhole site in Greene County Missouri. The acquired ERT data were processed as both 2D data and pseudo-3D data. Based on the correlation with the available core hole control, multichannel analysis of surface waves (MASW) data and field observations, it is concluded that the subsurface structure of the sinkhole is more reliably imaged on the pseudo-3D dataset than in the 2D dataset. The interpretation results of the pseudo-3D ERT indicated that the sinkhole developed at the intersection of three vertical solution-widened joint sets.

Geophysical surveys are widely used to reconstruct subsoil seismo-stratigraphic structures with a non-invasive approach. In this study the geophysical surveys were carried out with the aim to characterise the San Giorgio Cathedral in Ragusa (Italy) and the area on which it is built from a dynamic point of view. A 3D subsoil model was realised through the integration of two active (i.e., seismic tomography and multichannel analysis of surface waves) and one passive seismic technique (horizontal to vertical spatial ratio). The instrumentation used for the latter method consists of a tromograph (Tromino®), which is also employed for the characterisation of the building, focusing on the façade and the dome, by means of an ambient vibration test, processed through the standard spectral ratio and frequency domain decomposition methods. Integration of the 3D model, showing the distribution of areas with different physicomechanical characteristics, enables identifying anomalies that are likely attributable to the remains of the ancient Byzantine church of San Nicola. Four lower modes mainly involving the two investigated macroelements are identified. The experimental results outline the advantages of the use of the tromograph both for soil and structural characterisation, especially for massive masonry buildings located in areas with high seismic hazard.

In Western-Atakent (İstanbul), population density is increasing day by day and settlement areas are expanding. Soil properties and landslide conditions of these expanding regions must be absolutely examined. In the geophysics, there are many methods used to investigate landslide risks and geotechnical structure. The most common geophysical methods used for this purpose are the Electrical resistivity tomography (ERT), Multi-channel Analysis of Surface Waves (MASW) and Microtremor Survey Method (MSM) methods. These methods are very successful techniques for defining underground layers as geological structures, stratigraphic elements, soil layer thickness and landslide. Because of that reason in this study, soil properties and possibility of landslides of the Western-Atakent (İstanbul) region were investigated by using ERT, MASW, MSM and drilling methods. In this study the first stage, electrical resistivity data have been measured using dipole-dipole method on two profiles for ERT. In the second stage, MASW measurements have been made at 25 points on 5 seismic profiles in the field. In the third stage, MSM measurements have been made to determine the fundamental period in the 5-measure station in the study area. In the fourth and final stage, 10-pieces boreholes with a depth of 20 m were drilled to reveal the lithological structure of the study area. As a result of the evaluation of all data, parts of the region that could form landslides were revealed.

Lefkada and Corfu old towns are located in the western part of Greece, in the Ionian Sea. Their proximity to the Hellenic subduction zone (HSZ) is the reason for their intense seismicity. The main goal of this study was the estimation of the geotechnical characteristics of the subsurface, with the contribution of applied geophysical techniques. Therefore, seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) were applied. A total of thirty-three (33) seismic and geoelectrical profiles were performed in both towns in order to evaluate the geotechnical characteristics of the subsurface formations. Additionally, subsurface resistivity distributions were investigated with the application of electrical resistivity tomography (ERT). Some important elastic moduli were calculated through the combination of estimated seismic wave velocities and laboratory density measurements. The horizontal distribution of seismic velocities and mechanical properties (σ, E, K, G) of Corfu town was illustrated in maps, for the depth of 5 m. The geophysical interpretation also revealed that Lefkada’s subsurface consists of only one compact geological formation, with little or no variation of its geophysical-geotechnical characteristics. Beyond that, the ground type classifications for the two towns were determined according to the European Committee for Standardization Eurocode 8, based on VS30 values.

Associated with the exploitation of metallic minerals in Europe during the 20th century, several mining areas were abandoned without adequate environmental intervention. Furthermore, these areas lack studies to characterize the impact of pollution on the hydrogeological system. The area surrounding the tungsten mine of Regoufe, in northern Portugal, is one such area exploited during the Second World War. The accumulation of sulfide-rich tailings may have caused an acid mine drainage (AMD), where the leaching processes caused by seepage water led to soil contamination, evidenced by its acid character and anomalous concentrations of some Potentially Toxic Elements (PTE) reported in previous studies. The present research proposes an innovative approach that seeks the integration of different geophysical techniques to characterize the impact of mining activity on the subsurface. Electrical resistivity (ER) and electromagnetic (EM) were used to measure subsurface electrical properties. In addition, seismic refraction and Multichannel Analysis of Surface Waves (MASW) were performed to characterize the geometry, depth, and geomechanical behavior of the soil and rock bodies. The integration of these techniques allowed the interpretation of hydrogeological sections and a 3D resistivity volume to gain insight into the distribution of potentially contaminating fluids and tailings material present in the mining valley.

Near-surface seismic surveys are often designed for surface wave and seismic tomographic analysis. In recent years, seismic imaging methods have been more frequently used at this scale. Recognition of near-surface structures using a single method is insufficient because of the ambiguity of the inversion problem. As a solution, the authors propose a multi-step approach, where several different seismic methods are used in a particular order, to achieve an optimal model. A multi-method approach allows utilisation of a whole spectrum of recorded data, even the elements that are treated as background noise in other techniques. In classical processing approach, information about data uncertainty is often omitted or used in the simplest way for the single method only. This work presents an updated approach to uncertainty analysis by transferring estimated uncertainty between processing steps. By assuming that every consecutively applied method is more certain, the authors were able to obtain accurate velocity fields for seismic imaging, as the main information received from the previous steps. Based on information from multiple methods, a seismic stack in the depth domain was created as a final result, with an estimate of uncertainty.

A case study using shear wave velocity (Vs) data obtained from seismic multi-channel analysis of surface wave (MASW) studies was used to evaluate site conditions in Phrae City, Northern Thailand. The MASW data was acquired at 40 sites that covered the entire city area. The main goal was to generate seismic microzonation maps for Phrae City. The NEHRP map generated from the Vs data closely matched the surficial geological map. Areas mapped as alluvium soil were assigned to NEHRP soil class D, while areas mapped as colluvium and river terrace soils, in contrast, fell into the NEHRP soil class C. The amplification map indicated a higher amplification in the west and central part of the city, where the soils mostly consisted of soft sediments from alluvial deposits. The eastern study area had a relatively low amplification, because the sediments in this area mostly consisted of coarse grain sediments. The site period map revealed that three- to four-story buildings were likely to be susceptible to ground shaking in most parts of the city, whereas one- to two-story buildings were only vulnerable in the eastern part of the study area.

The critical zone (CZ) represents the most-shallow subsurface, where the bio-, hydro-, and geospheres interact with anthropogenic activity. To characterize the thickness and lateral variations of the CZ, here we focus on the Eastern Betic Shear Zone (EBSZ), one of the most tectonically active regions in the Iberian Peninsula. Within the EBSZ, the Guadalentín Depression is a highly populated area with intensive agricultural activity, where the characterization of the CZ would provide valuable assets for land use management and seismic hazard assessments. To achieve this, we have conducted an interdisciplinary geophysical study along the eastern border of the Guadalentín Depression to characterize the CZ and the architecture of the shallow subsurface. The datasets used include Electrical Resistivity Tomography (ERT), first-arrival travel time seismic tomography, and multichannel analysis of surface waves (MASW). The geophysical datasets combined help to constrain the high-resolution structure of the subsurface and image active fault systems along four transects. The resulting geophysical models have allowed us to interpret the first ~150 m of the subsurface and has revealed: (i) the variable thickness of the CZ; (ii) the CZ relationship between the fault zone and topographic slope; and (iii) the differences in CZ thickness associated with the geological units. Our results provide a method for studying the shallow subsurface of active faults, complementing previous geological models based on paleo-seismological trenches, and can be used to improve the CZ assessment of tectonically active regions.

Las propiedades dinámicas determinan el comportamiento elástico de los suelos, y su cálculo es de interés en el estudio de la interacción-suelo estructura. En la ciudad de Ocaña se desconoce el valor de estas propiedades, por lo cual se desarrollaron un conjunto de ensayos geofísicos para la medición de ondas primarias y posterior cálculo de las propiedades que permitirían hacer un mejor análisis dinámico del suelo. Inicialmente se seleccionaron los sitios para la realización de los ensayos de Refracción sísmica y Análisis Multicanal de Ondas Superficiales. Posteriormente se inició la etapa de procesamiento con el software SeisImager/2D y SeisImager/SW2D para determinar el valor de la velocidad de onda P y S. Mediante fórmulas de la teoría de elasticidad se determinaron las propiedades dinámicas del suelo y finalmente se realiza un análisis estadístico de los resultados, se pudo determinar que la mayor parte de la ciudad de Ocaña se encuentra constituida por una formación geológica de origen sedimentario, compuesta por materiales areno-arcillosos y arcillo-limosos de alta plasticidad. Los valores promedio en estos materiales son: módulo de rigidez entre 135,98MPa y 242,19MPa, módulo de elasticidad entre 709,51MPa y 364,71MPa y coeficiente de Poisson entre 0,393 y 0,467.

Next generation ground motion prediction models use shear-wave velocity over the top 30 m of subsoil (VS30) as an important assessment parameter of seismic ground surface motion. VS30 can be measured using invasive methods, such as boreholes, or non-invasive methods, such as multichannel analysis of surface waves (MASW). To evaluate this technique in a variety of near-surface conditions, MASW-derived shear-wave velocity profiles (s-wave velocity vs. depth) were statistically compared to direct borehole measurements from three locations of Merapi sediment found on the Universitas Muhammadiyah Yogyakarta (UMY) campus site. A detailed study of the effect from the total number of recording channels of MASW, sampling intervals, source offset, and receiver spacing was conducted near the borehole test site. The soil was classified as a medium soil or SD. The MASW method, which is non-destructive and non-invasive in nature and relatively faster in assessment, provides more reliable shear-wave velocity profiles, i.e. from 0 to 30 meters below the ground surface.

Investigating sinkhole morphology and formation mechanisms is key to understanding their long term impact and susceptibility to development, and aids in the design of effective mitigation measures. In this study, ERT (electrical resistivity tomography), MASW (multichannel analysis of surface waves) and borehole data were used to image the subsurface morphology of an active sinkhole in Greene County, Missouri. The study reveals that the sinkhole developed along a natural surface drainage pathway above a pervasively fractured limestone. The subsurface image of the sinkhole depicts a zone of near-vertical water seepage and soil piping. Based on the nature of the overburden material, and the morphology and current/past surface expression of the sinkhole, it is concluded that the sinkhole is predominantly a cover subsidence type of sinkhole. However, it is possible that minor cover collapse occurred locally and in an area slightly to the north of the current active sinkhole.

In this study, Multichannel Analysis of Surface Waves Method (MASW), seismic refraction tomography and seismic reflection methods are used together at Silivri district in Istanbul – a district with a landslide problem because of the high speed rail line project crossing through the area. The landslide structure, border and depth of the slip plane are investigated and correlated within the local geology. According to the obtained 2D seismic sections, the landslide occurs through the East-West direction in the study area and the landslide slip plane with its border are clearly obtained under the subsurface. The results prove that the study area is suitable enough for the landslide development and this evolution also affects the high speed rail line project.

The primary goal of this study is to generate the NEHRP soil classification map for Lamphun City using the average shear wave velocity values (Vs(30)) derived from the multi-channel analysis of surface wave (MASW) data. The secondary goal is to use the Vs(30) data to create the preliminary site amplification map of the city. For this work, multi-channel surface wave seismic data were acquired at 48 preselected sites in the Lamphun City area, northern Thailand. After generating the NEHRP map, soil class D is found to be present mostly in the northern part of the area, while soil class C is found mostly in the southern part. A major part of the Lamphun City is located on soil class D. The soil amplification map indicates higher amplification in the east, north and west of the city, where the soils consisted of mostly soft sediments from the alluvial plain and river terrace. The central and south eastern parts of Lamphun City had a relatively low amplification, perhaps because the sediment in this part is relatively thin or the bedrock is shallow. The results of study imply that the major part of Lamphun city may experience earthquake ground shaking due to amplification of the soft soils.

The paper is devoted to the perspective trend of researches on estimation of physical and mechanical characteristics of dispersive soils by means of non-destructive methods of in-situ testing by wave analysis. The paper presents the results of comparison of the values of the transition coefficient between the soil dynamic elastic modulus, which can be calculated from the results of in-situ tests by means of non-destructive technique of Multichannel Analysis of Surface Waves, and the soil deformation modulus. Application of such a transition factor makes it possible to estimate the soil deformation modulus according to the soil elastic characteristics determined using modern non-destructive express techniques of wave analysis of the low velocity zone of the upper part of the profile. Due to the application of such express methods, labor and time costs of field investigations are significantly reduced during preliminary geotechnical site assessment. Comparison of different values of the transition factor was made on the basis of the results of laboratory standard triaxial tests and numerical experiments with the values calculated on the basis of dependencies proposed by the results of in-situ tests with Plate Load Tests and Multichannel Analysis of Surface Waves in previous in-situ studies. The results of standard triaxial tests on samples of cohesive and non-cohesive soils confirm the dependence of the transition factor on the soil unit weight, obtained in the previous stage of in-situ researches. The values of the transition factor based on the results of numerical experiments do not exceed the results obtained by field research methods. The results of the research will be useful in estimating the physical and mechanical properties of the soil during preliminary geotechnical calculations of the foundations. All in-situ investigations are carried out using non-destructive technique. No permits or approvals are required to perform the work according to the proposed methodology.

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

Typically, the mitigation of coastal erosion is achieved by amending surface conditions using materials, such as concrete. The objective of this study is to evaluate the feasibility of constructing artificial beachrocks using natural materials (e.g., microbes, sand, shell, pieces of coral, and seaweed, etc.) within a short time, and to propose the method as a novel strategy for coastal protection. Initially, a survey on resistivity and a multichannel analysis of seismic waves (MASW) were conducted along the coastal lines to characterize and elucidate the subsurface structure of existing beachrocks in the Southeast Yogyakarta coastal area, Krakal–Sadranan beach, Indonesia. The field survey on natural beachrocks suggested that both resistivity and shear wave velocity were higher in the deeper deposits compared to the underlying unconsolidated sand layer within a depth of approximately 1.5 m and covering an area of 210.496 m2 for the α-section and 76.936 m2 for the β-section of beachrock deposit. The results of the sand solidification test in the laboratory showed that treated sand achieved unconfined compressive strength of up to around 6 MPa, determined after a treatment period of 14 days under optimum conditions.

A site located on the island of Brač is known in history for world-famous architectural stone and stone mining, dating all the way back to ancient Greek and Roman times. The most famous building constructed from the stone from Brač is the Diocletian Cesar Palace in the town Split. Prospective new locations for quarries are still required because the demand for the stone from the island is still high. This paper presents a review of undertaken geophysical investigations, as well as engineering geologic site prospection, with the purpose of determining if the rock mass quality is suitable for the mining of massive blocks needed for an architectural purpose—dimension stones. Several surface noninvasive geophysical methods were applied on the site, comprising of two seismic methods, multichannel analysis of surface waves (MASW) and shallow refraction seismic (SRS) electrical methods of electrical resistivity tomography (ERT), as well as electromagnetic exploration with ground penetrating radar (GPR). Results of geophysical investigations were compared to the engineering geologic prospection results, as well to the visible rock mass structure and observed discontinuities on the neighboring existing open mine quarry. Rock mass was classified into three categories according to its suitability for dimension stone exploitation. Each category is defined by compressional and shear seismic velocities as well as electrical resistivity. It has been found that even small changes in moisture content within the large monolithic rock mass can influence measured values of electrical resistivity. In the investigated area, dimension stone quarrying is advisable if the rock mass has values of resistivity higher than 3000 Ωm, as well as compressional seismic velocities higher than 3000 m/s and shear wave velocities higher than 1500 m/s. Georadar was found to be a good tool for the visual determination of fissured systems, and was used to confirm findings from other geophysical methods.

A geophysical study of Multichannel Analysis of Surface Waves (MASW) was carried out in a sector where seven boreholes were made with available data of N number of blows from Standard Penetration Tests (SPT) in all of them, with the objective of determining soil stability and classification in a sector of some 10,000 m2 where a work of civil infrastructure is planned to be installed. The site is located south of 9 de Julio Department, in the province of San Juan, Argentina. Eight MASW were recorded, and S-waves´ 1-D profiles were calculated to depths near 30m at critical points of the study area. The type of soil was determined with experimental data along with calculated values of VS. With available data of N and VS in three boreholes where both MASWs were carried out very close from each other, the law of variation of VS with N for each case was calculated through an adjustment algorithm, comparing the expressions with other ones already published. Finally, this equation was employed to calculate (predict) VS based on N for those boreholes where there were only data of N from SPT.

Horizontally polarized shear wave (SH) refraction and multichannel analysis of surface wave (MASW) methods have been carried out in Hatyai City, southern Thailand, a pilot study for site classification, part of the National Earthquake Hazards Reduction Program (NEHRP). The objectives of this study are the comparison of the efficiencies of different shear wave velocity (Vs) determination techniques and the use of Vs measurements of the prediction of standard penetration resistance (SPT-N). Good correlation between all Vs profiles and SPT-N values and local lithology are observed. However, there are systematic differences between SH-refraction based-Vs and MASW based-Vs, which might be explained by possible converted waves, limitations of the assumptions used, poor quality of the acquired data, and limitations of the inversion procedures of the methods applied. From the integrated use of Vs from both methods an empirical formula to describe the correlation between Vs and SPT-N values has been proposed and can be used to estimate geotechnical parameters in areas where no borehole or geophysical investigation exist.

Основной целью данного исследования является моделирование влияния локальных грунтовых условий в пределах осадочных бассейнов. Принимая во внимание такие влияния, как геологические условия и строение, уровень грунтовых вод, влияние человеческой деятельности на грунтовые условия, вторичные геологические эффекты и т.д. мы, в основном, сосредоточились на комплексном анализе грунтовых условий. Для этого были использованы данные плотной сети измерений на территории Гюмри в дополнение к существующим данным. Эти данные были использованы для изучения пространственной корреляции структуры скоростей S-волн и преобладающих периодов микротреморов в Гюмрийской части Ширакского осадочного бассейна. На основе моделей распространения поверхностных волн и микротреморов в пределах генерального плана г. Гюмри были получены: средняя характеристическая скорость, равная 310м/с, и преобладающие периоды собственных колебаний грунтов (F0

In this paper the results of a detailed seismic microzonation, performed at Sant’Agata Fossili (Piemonte region, northern Italy) are presented. We study the local seismic response of this small village using a level 3, that is the most accurate level following the Italian code of seismic microzonation. The activity steps consist in a gradual widening of knowledge of the different aspects of the amplification phenomena. A multidisciplinary approach has been performed to obtain the local seismic response: including a study of local geology, geophysical and geotechnical characterization of the lithologies, and numerical and experimental analyses. We finally compare the obtained elastic response spectra to the prescribed spectra of the Italian Building Code (in Italian: Norme Tecniche per le Costruzioni). Our results show the geologic and geophysical differences of the subsoil, that produce different local seismic response in terms of amplification factors and acceleration response spectra.

In recent years, the Lamb wave analysis by the multi-channel analysis of surface waves (MASW) for concrete structures has been an effective nondestructive evaluation, such as the condition assessment and dimension identification by the elastic wave velocities and their reflections from boundaries. This study proposes an effective Lamb wave analysis by the practical application of MASW to concrete wide beams in an easy and simple manner in order to identify the dimension and elastic wave velocity (R-wave) for the condition assessment (e.g., the estimation of elastic properties). This is done by identifying the zero-order antisymmetric (A0) and first-order symmetric (S1) modes among multimodal Lamb waves. The MASW data were collected on eight concrete wide beams and compared to the actual depth and to the pressure (P-) wave velocities collected for the same specimen. Information is extracted from multimodal Lamb wave dispersion curves to obtain the elastic stiffness parameters and the thickness of the concrete structures. Due to the simple and cost-effective procedure associated with the MASW processing technique, the characteristics of several fundamental modes in the experimental Lamb wave dispersion curves could be measured. Available reference data are in good agreement with the parameters that were determined by our analysis scheme.