Determination of shear wave velocity and depth to basement using multichannel analysis of surface wave technique

T. Seshunarayana, N. Sundararajan

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The dispersive characteristics of Rayleigh type surface waves were utilized to estimate shear wave velocity (Vs) profile followed by imaging the shallow subsurface granitic layers in the heart of Hyderabad. The reliability of Multichannel Analysis of Surface Waves (MASW) depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Multichannel recording leads to effective identification and isolation of various factors of noise. Calculating the 1-D shear wave velocity (Vs) field from surface waves ensures high degree of accuracy irrespective of cultural noise. The main advantage of mapping the bed rock surface with shear wave velocity (Vs) is the insensitivity of MASW to velocity inversion besides being free from many constraints such as contrast in physical properties etc. Modeling of surface waves data results a shear wave velocity (Vs) of 250-750 m/s covering the top soil to weathering and up to bedrock corresponding to a depth range of 10-30 m. Further, the computed N values (which is an indicator of site characteristic) based on the harmonic shear wave velocity up to a depth of 5 m is found to be quite high (> 25-30) well above 5 indicating the site to be safe and strong enough and not prone to liquefaction. A pair of selected set of results over granites are presented here as a case study highlighting the salient features of MASW.

Original languageEnglish
Pages (from-to)499-504
Number of pages6
JournalJournal of the Geological Society of India
Volume80
Issue number4
DOIs
Publication statusPublished - Oct 2012

Fingerprint

surface wave
wave velocity
S-wave
phase velocity
Rayleigh wave
velocity profile
liquefaction
topsoil
analysis
bedrock
weathering
physical property
rock
modeling

Keywords

  • Andhra Pradesh
  • Density
  • Dispersion
  • Granites
  • MASW
  • Shear wave velocity
  • Surface waves

ASJC Scopus subject areas

  • Geology

Cite this

@article{82e5542e6cee4c8a8c93ab20fd5ec3ec,
title = "Determination of shear wave velocity and depth to basement using multichannel analysis of surface wave technique",
abstract = "The dispersive characteristics of Rayleigh type surface waves were utilized to estimate shear wave velocity (Vs) profile followed by imaging the shallow subsurface granitic layers in the heart of Hyderabad. The reliability of Multichannel Analysis of Surface Waves (MASW) depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Multichannel recording leads to effective identification and isolation of various factors of noise. Calculating the 1-D shear wave velocity (Vs) field from surface waves ensures high degree of accuracy irrespective of cultural noise. The main advantage of mapping the bed rock surface with shear wave velocity (Vs) is the insensitivity of MASW to velocity inversion besides being free from many constraints such as contrast in physical properties etc. Modeling of surface waves data results a shear wave velocity (Vs) of 250-750 m/s covering the top soil to weathering and up to bedrock corresponding to a depth range of 10-30 m. Further, the computed N values (which is an indicator of site characteristic) based on the harmonic shear wave velocity up to a depth of 5 m is found to be quite high (> 25-30) well above 5 indicating the site to be safe and strong enough and not prone to liquefaction. A pair of selected set of results over granites are presented here as a case study highlighting the salient features of MASW.",
keywords = "Andhra Pradesh, Density, Dispersion, Granites, MASW, Shear wave velocity, Surface waves",
author = "T. Seshunarayana and N. Sundararajan",
year = "2012",
month = "10",
doi = "10.1007/s12594-012-0169-x",
language = "English",
volume = "80",
pages = "499--504",
journal = "Journal of the Geological Society of India",
issn = "0016-7622",
publisher = "Geological Society of India",
number = "4",

}

TY - JOUR

T1 - Determination of shear wave velocity and depth to basement using multichannel analysis of surface wave technique

AU - Seshunarayana, T.

AU - Sundararajan, N.

PY - 2012/10

Y1 - 2012/10

N2 - The dispersive characteristics of Rayleigh type surface waves were utilized to estimate shear wave velocity (Vs) profile followed by imaging the shallow subsurface granitic layers in the heart of Hyderabad. The reliability of Multichannel Analysis of Surface Waves (MASW) depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Multichannel recording leads to effective identification and isolation of various factors of noise. Calculating the 1-D shear wave velocity (Vs) field from surface waves ensures high degree of accuracy irrespective of cultural noise. The main advantage of mapping the bed rock surface with shear wave velocity (Vs) is the insensitivity of MASW to velocity inversion besides being free from many constraints such as contrast in physical properties etc. Modeling of surface waves data results a shear wave velocity (Vs) of 250-750 m/s covering the top soil to weathering and up to bedrock corresponding to a depth range of 10-30 m. Further, the computed N values (which is an indicator of site characteristic) based on the harmonic shear wave velocity up to a depth of 5 m is found to be quite high (> 25-30) well above 5 indicating the site to be safe and strong enough and not prone to liquefaction. A pair of selected set of results over granites are presented here as a case study highlighting the salient features of MASW.

AB - The dispersive characteristics of Rayleigh type surface waves were utilized to estimate shear wave velocity (Vs) profile followed by imaging the shallow subsurface granitic layers in the heart of Hyderabad. The reliability of Multichannel Analysis of Surface Waves (MASW) depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Multichannel recording leads to effective identification and isolation of various factors of noise. Calculating the 1-D shear wave velocity (Vs) field from surface waves ensures high degree of accuracy irrespective of cultural noise. The main advantage of mapping the bed rock surface with shear wave velocity (Vs) is the insensitivity of MASW to velocity inversion besides being free from many constraints such as contrast in physical properties etc. Modeling of surface waves data results a shear wave velocity (Vs) of 250-750 m/s covering the top soil to weathering and up to bedrock corresponding to a depth range of 10-30 m. Further, the computed N values (which is an indicator of site characteristic) based on the harmonic shear wave velocity up to a depth of 5 m is found to be quite high (> 25-30) well above 5 indicating the site to be safe and strong enough and not prone to liquefaction. A pair of selected set of results over granites are presented here as a case study highlighting the salient features of MASW.

KW - Andhra Pradesh

KW - Density

KW - Dispersion

KW - Granites

KW - MASW

KW - Shear wave velocity

KW - Surface waves

UR - http://www.scopus.com/inward/record.url?scp=84871529887&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84871529887&partnerID=8YFLogxK

U2 - 10.1007/s12594-012-0169-x

DO - 10.1007/s12594-012-0169-x

M3 - Article

VL - 80

SP - 499

EP - 504

JO - Journal of the Geological Society of India

JF - Journal of the Geological Society of India

SN - 0016-7622

IS - 4

ER -