Influence of source distance on site-effects in Delhi city
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
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Title |
Influence of source distance on
site-effects in Delhi city
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Creator |
Parvez, Imtiyaz A
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Subject |
Computational Seismology
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Description |
The seismic ground motion along a geological crosssection
from Tilak Bridge to Punjabi Bagh in Delhi
city has been simulated at every 130 m with a hybrid
technique (modal summation and finite differences).
We use two earthquake source scenarios: (1) 27 August
1960, M = 6.0 at a distance of about 45 km (near source)
and (2) a large (M = 8.0) earthquake due in the central
seismic gap in the Himalayan region, at a distance of
about 225 km (far source). We focus on the influence
of the seismic source location and focal mechanism on
site-response, which, in general, is neglected in traditional
site-effect studies. We compare the Response
Spectra Ratio (RSR) for frequency up to 3 Hz computed
due to far and near sources. We observe 6–7 times
higher amplification in the radial component at around
2–2.5 Hz due to the far source as-compared to the near
source. However, there is some amplification, of the
order 2–3, at lower frequencies (less than 1 Hz) due to
the near source, which is missing when the far source
is considered. To validate our results, we compare the
RSR, obtained from the signals at soft sites, namely
CPCB, IHC and CSIR, normalized to the bedrock
Ridge site, recorded during Chamoli earthquake of
1999, with that at similar sites theoretically computed
along our 2D geological cross-sections
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Publisher |
Indian Academy of Sciences
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Date |
2006-09-25
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://cir.cmmacs.ernet.in/28/1/curr%2Dsc%2D2006.pdf
Parvez, Imtiyaz A (2006) Influence of source distance on site-effects in Delhi city. Current Sciences , 91 (6). pp. 827-835. ISSN 0011-3891 |
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Relation |
http://www.ias.ac.in/currsci
http://cir.cmmacs.ernet.in/28/ |
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