Seismic hazard assessment of Chennai city considering local site effects

• Published in: Journal of Earth System Science Vol. 117; no. Suppl 2; pp. 853 - 863
• Main Authors: Boominathan, A., Dodagoudar, G. R., Suganthi, A., Uma Maheswari, R.
• Format: Journal Article
• Language: English
• Published: India Springer-Verlag 01.11.2008; Springer Nature B.V
• Subjects: Acceleration; Amplification; Cities; Design parameters; Dimensional analysis; Earth and Environmental Science; Earth Sciences; Earthquakes; Geological hazards; Ground motion; Hazard assessment; Hazards; Parameters; Response analysis; S waves; Sandy soils; Seismic activity; Seismic hazard; Seismic velocities; Seismicity; Seismology; Shear wave velocities; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Studies; Surface water waves; Surface waves; Velocity distribution; Velocity profiles; Wave velocity; Chennai India; India; shear wave velocity; characteristic site period; spectral acceleration ratio; Seismic hazard; SHAKE91
• ISSN: 0253-4126; 0973-774X
• DOI: 10.1007/s12040-008-0072-4

Chennai city suffered moderate tremors during the 2001 Bhuj and Pondicherry earthquakes and the 2004 Sumatra earthquake. After the Bhuj earthquake, Indian Standard IS: 1893 was revised and Chennai city was upgraded from zone II to zone III which leads to a substantial increase of the design ground motion parameters. Therefore, a comprehensive study is carried out to assess the seismic hazard of Chennai city based on a deterministic approach. The seismicity and seismotectonic details within a 100 km radius of the study area have been considered. The one-dimensional ground response analysis was carried out for 38 representative sites by the equivalent linear method using the SHAKE91 program to estimate the ground motion parameters considering the local site effects. The shear wave velocity profile was inferred from the corrected blow counts and it was verified with the Multichannel Analysis of Surface Wave (MASW) test performed for a representative site. The seismic hazard is represented in terms of characteristic site period and Spectral Acceleration Ratio (SAR) contours for the entire city. It is found that structures with low natural period undergo significant amplification mostly in the central and southern parts of Chennai city due to the presence of deep soil sites with clayey or sandy deposits and the remaining parts undergo marginal amplification.