Shallow-to-deep shear wave velocity profiling by surface waves in complex ground for enhanced seismic microzonation of Las Vegas, Nevada

The availability of a unique database, where all data of the seismic microzonation studies carried out in about 1900 municipalities of Italy (https://www.webms.it/) are achieved with a standardized format, allowed statistical elaborations in terms of subsoil parameters. In particular, we analysed borehole logs and geophysical data in order to characterize them with the shear wave velocity (Vs) vertical profile, and the code of standardized engineering geological units, according to the Italian Guidelines for Seismic Microzonation (Seismic Microzonation Working Group, 2015; 2018). The Vs parameter, extracted from about 3700 geophysical surveys, was correlated to the engineering geological units from the borehole logs, with 1meter step. The correlation was performed for about 1700 available Down-Hole (DH) surveys and for about 2000 Multichannel Analyses of Surface Waves (MASW). For these latter, we selected only MASW surveys located near boreholes, no more than 100 m away. The statistical analysis on the distribution and dispersion of Vs parameter allowed to calculate the Vs values related to the mode, mean, median, standard deviation, first quartile, third quartile, minimum and maximum, and the trend with depth of Vs for each engineering geological unit. Validation with external datasets (e.g. Italian Vs30 map, Mori et al., 2020) demonstrates that the characterization of engineering geological units in term of Vs, based on velocity profiles extracted by the Italian seismic microzonation dataset, allow to reliably characterize the engineering geological model, where no geophysical data are available. Statistics of subsoil parameters will represent a fundamental tool for computing local seismic ground motion parameters (e.g. PGA, HSM) in the areas not covered by seismic microzonation studies.References- Mori, F., Mendicelli, A., Moscatelli, M., Romagnoli, 796 G., Peronace, E., Naso, G., 2020. A new Vs30 map for Italy based on the seismic microzonation dataset. Engineering Geology 275, 105745. https://doi.org/10.1016/j.enggeo.2020.105745.- Seismic Microzonation Working Group, 2015. Guidelines for Seismic Microzonation http://www.protezionecivile.gov.it/httpdocs/cms/attach_extra/GuidelinesForSeismicMicrozonation.pdf- Seismic Microzonation Working Group, 2018. Standard di rappresentazione e archiviazione informatica Versione 4.1. http://www.protezionecivile.gov.it/attivita-rischi/rischio-sismico/attivita/commissione-supporto-monitoraggio-studi-microzonazione/standard-rappresentazione-archiviazione-informatica

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Shear‐wave velocity based seismic microzonation of Lorca city (SE Spain) from MASW analysis

Near Surface Geophysics ◽

10.3997/1873-0604.2014032 ◽

2014 ◽

Vol 12 (6) ◽

pp. 739-750 ◽

Cited By ~ 7

Author(s):

P. Martínez‐Pagán ◽

M. Navarro ◽

J. Pérez‐Cuevas ◽

F.J. Alcalá ◽

A. García‐Jerez ◽

...

Keyword(s):

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Seismic Microzonation ◽

Se Spain

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Site Characterization of Existing and Abandoned Coal Ash Ponds Using Shear-Wave Velocity from Multichannel Analysis of Surface Waves

Journal of Geotechnical and Geoenvironmental Engineering ◽

10.1061/(asce)gt.1943-5606.0002366 ◽

2020 ◽

Vol 146 (11) ◽

pp. 04020115

Author(s):

Partha Sarathi Parhi ◽

Umashankar Balunaini ◽

Sasanka Mouli Sravanam ◽

Vinod Kumar Mauriya

Keyword(s):

Surface Waves ◽

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Coal Ash ◽

Site Characterization ◽

Ash Ponds ◽

Multichannel Analysis

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Shear Wave Velocity Profiles of Roadway Substructures from Multichannel Analysis of Surface Waves and Waveform Tomography

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2655-06 ◽

2017 ◽

Vol 2655 (1) ◽

pp. 36-44

Author(s):

Khiem T. Tran ◽

Justin Sperry ◽

Michael McVay ◽

Scott J. Wasman ◽

David Horhota

Keyword(s):

Data Acquisition ◽

Surface Waves ◽

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Test System ◽

Acquisition Time ◽

Low Velocity ◽

Multichannel Analysis ◽

Waveform Tomography

Assessment of roadway subsidence caused by embedded low-velocity anomalies is critical to the health and safety of the traveling public. Surface-based seismic techniques are often used to assess roadways because of data acquisition convenience and large depths of characterization. To mitigate the negative impact of closing a traffic lane under traditional seismic testing, a new test system that uses a land streamer is presented. The main advantages of the system are the elimination of the need to couple the geophones to the roadway, the use of only one source at the end of the geophone array, and the movement of the whole test system along the roadway quickly. For demonstration, experimental data were collected on asphalt pavement overlying a backfilled sinkhole that was experiencing further subsidence. For the study, a 24-channel land streamer and a propelled energy generator to generate seismic energy were used. The test system was pulled by a pickup truck along the roadway and the data were collected with 81 shots at every 3 m for a road segment of 277.5 m, with a total data acquisition time of about 1 h. The measured seismic data set was analyzed by the standard multichannel analysis of surface waves (MASW) and advanced two-dimensional (2-D) waveform tomography methods. Eighty-one one-dimensional shear wave velocity (VS) profiles from the MASW were combined to obtain a single 2-D profile. The waveform tomography method was able to characterize subsurface structures at a high resolution (1.5- × 1.5-m cells) along the test length to a depth of 22.5 m. Very low S-wave velocity was obtained at the repaired sinkhole location. The 2-D VS profiles from the MASW and waveform tomography methods are consistent. Both methods were able to delineate high- and low-velocity soil layers and variable bedrock.

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