scholarly journals VS30 at three strong-motion recording stations in Napa and Napa County, California—Main Street in downtown Napa, Napa fire station number 3, and Kreuzer Lane—Calculations determined from s-wave refraction tomography and multichannel analysis of surface waves (Rayleigh and Love)

2018 ◽  
Author(s):  
Joanne H. Chan ◽  
Rufus D. Catchings ◽  
Mark R. Goldman ◽  
Coyn J. Criley
2017 ◽  
Vol 5 (3) ◽  
pp. T287-T298 ◽  
Author(s):  
Julian Ivanov ◽  
Richard D. Miller ◽  
Daniel Feigenbaum ◽  
Sarah L. C. Morton ◽  
Shelby L. Peterie ◽  
...  

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


2021 ◽  
Vol 24 (4) ◽  
pp. 473-484
Author(s):  
Cengiz Kurtuluş ◽  
Ibrahim Sertcelik ◽  
Fadime Sertçelik ◽  
Hamdullah Livaoğlu ◽  
Cüneyt Şaş

In this study, shallow seismic surveys, including seismic refraction, Multichannel Analysis of Surface Waves (MASW), Refraction Microtremor (ReMi), and Microtremor measurements were conducted to estimate site characterization at 26 strong-motion stations of AFAD (Disaster and Emergency Management Presidency) in the province of Hatay, situated in one of the most seismically active regions in southern Turkey. The Horizontal to vertical spectral ratio (HVSR) technique was applied, using smoothed Fourier spectra derived from a long duration series to determine dominant frequency values at different amplification levels. Shear wave velocity up to 30 m of the ground was detected with MASW analysis. In the ReMi analysis, up to 80 m was reached with a corresponding average of 650 m/s shear wave velocity. The shear wave velocities estimated by the MASW method up to 30 m were compared with those found by the ReMi method, and they were observed to be very compatible. The province of Hatay was classified according to Vs30 based NEHRP Provisions, Eurocode-8, the Turkish Building Earthquake Regulation (TBDY-2018), and Rodriguez-Marek et al. (2001). The shear-wave velocity (Vs30), Horizontal to Vertical ratio’s (H/V) peak amplitude, dominant period, and site class of each site were determined. The H/V peak amplitudes range between 1.9 and 7.6, while the predominant periods vary from 0.23 sec to 2.94sec in the study area. These results are investigated to explain the consistency of site classification schemes.


2015 ◽  
Author(s):  
Panagiotis C. Pelekis ◽  
Alexandros Savvaidis ◽  
Robert Kayen ◽  
Vasileios S. Vlachakis ◽  
George A. Athanasopoulos

2020 ◽  
Vol 25 (1) ◽  
pp. 18-20
Author(s):  
Muhammad Farhan ◽  
◽  
Gunawan Handayani ◽  

Every geotechnical measurement requires geophysical methods to classify soil types under the ground. S-wave velocity (Vs), P-wave velocity (Vp), and density (ρ), are the most important parameters in the classification of soils. There are various methods to determine Vs, one of them is P-S logging method. However, this method is less suitable to be applied in urban areas due to the difficulties of data acquisition and high expense in operational costs. In 1999, a seismic method uses surface waves to de-termine Vs profile with a higher signal to noise ratio which was known by the name of Multichannel Analysis of Surface Waves (MASW). A surface wave, especially Rayleigh wave, creeps slowly on the surface with a larger amplitude than a body wave. The wavelengths of the surface wave will disperse in the layers system i.e. the phase velocity of the surface waves is now func-tion of frequency. MASW 2-D method is used in this paper to determine subsoil properties and to identify the fault under the bridge abutments plan (abutment 1 and abutment 2) in Kelok Sago Jambi.


2012 ◽  
Vol 30 (2) ◽  
Author(s):  
Sérgio Bezerra Lima Júnior ◽  
Renato Luiz Prado ◽  
Rodolfo Moreda Mendes

This paper presents results from the MASW method (multichannel analysis of surface waves) in a hill side area of unsaturated soils in the Ubatuba City,Brazil, a site where numerous mass movements have occurred. It discusses the influence of some acquisition parameters, such as, the natural frequency of geophones and minimum and maximum offsets in dispersion image results and does a comparative analysis of the results obtained in repeated tests carried out in the same place, under the same conditions, during the dry and rainy seasons. The comparative analysis for the inversion results in different periods showed that the values of S-wave velocity during the dry season were higher than those for the rainy season; these variations were attributed to the higher cohesion of the soil structure in the dry season. The final 1D velocity profile model with depth was consistent with the results of other geophysical and geotechnical investigations made. Although additional in situ and laboratory geotechnical tests, are necessary (to obtain soil parameters such as hydraulic conductivity, moisture content, soil suction, for example), for a complete characterization of the geotechnical properties of the investigated soil, the result shows that it is possible to use empirical correlations between the Vs profile, from the MASW method, and soil stiffness parameters in order to monitor areas susceptible to landslide.


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