Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

After the Bhuj earthquake the national capital region of Delhi attracted major attention of several scientific studies in the recent times. Since Delhi falls in zone IV (IS 1893: 2002) with high seismic activity, there is a great need for site characterization and seismic hazard mapping of the area. Multi Channel Analysis of Surface Wave (MASW) tests were done in Delhi at 118 sites in predefined grids of 2kmX3km each. Shear-wave velocity, VS, is an important parameter for evaluating dynamic behavior of soil. This test carried outdone using 48 channel digital seismograph with 4.5 Hz geophones. Data was analyzed using SeisImager/SW software and two dimensional shear wave velocity models at every 5m depth from ground surface was developed. It is observed that the value of Vs is ranging from 400 to 480 m/s in the rocky sites, it is 120 to 250m/s in trans Yamuna region and 250 to 370m/s in western side of the area. The shear wave velocity values are exactly matching with the geological and geotechnical characteristics of the subsoil strata. Also, the field shear wave velocity from MASW test is compared with the estimated values using the empirical formulae developed. It is observed that the experimental shear wave velocity and the empirically estimated values are almost equal up to 20m depth. But at depths greater 20m, Vs from MASW test are slightly higher than the calculated value using empirical formulae developed. Average shear wave velocity at 30m depth i.e., VS30 is also calculated and is ranging from 185 to 495 m/s for Delhi region. Also, correlations among Vs, SPT ‘N’, depth ‘D’ are developed using the available borehole data. These correlations are useful to estimate the shear wave velocity at any depth with out performing the actual test in Delhi region.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Multi Channel Analysis of Surface Wave (MASW) Testing for Dynamic Site Characterization of Delhi Region

San Diego, California

After the Bhuj earthquake the national capital region of Delhi attracted major attention of several scientific studies in the recent times. Since Delhi falls in zone IV (IS 1893: 2002) with high seismic activity, there is a great need for site characterization and seismic hazard mapping of the area. Multi Channel Analysis of Surface Wave (MASW) tests were done in Delhi at 118 sites in predefined grids of 2kmX3km each. Shear-wave velocity, VS, is an important parameter for evaluating dynamic behavior of soil. This test carried outdone using 48 channel digital seismograph with 4.5 Hz geophones. Data was analyzed using SeisImager/SW software and two dimensional shear wave velocity models at every 5m depth from ground surface was developed. It is observed that the value of Vs is ranging from 400 to 480 m/s in the rocky sites, it is 120 to 250m/s in trans Yamuna region and 250 to 370m/s in western side of the area. The shear wave velocity values are exactly matching with the geological and geotechnical characteristics of the subsoil strata. Also, the field shear wave velocity from MASW test is compared with the estimated values using the empirical formulae developed. It is observed that the experimental shear wave velocity and the empirically estimated values are almost equal up to 20m depth. But at depths greater 20m, Vs from MASW test are slightly higher than the calculated value using empirical formulae developed. Average shear wave velocity at 30m depth i.e., VS30 is also calculated and is ranging from 185 to 495 m/s for Delhi region. Also, correlations among Vs, SPT ‘N’, depth ‘D’ are developed using the available borehole data. These correlations are useful to estimate the shear wave velocity at any depth with out performing the actual test in Delhi region.