Long Period Ground Motion at Bedrock Level in Delhi City from Himalayan Earthquake Scenarios
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Title |
Long Period Ground Motion at Bedrock Level in Delhi City from Himalayan Earthquake
Scenarios
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| Creator |
Parvez, Imtiyaz A
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| Subject |
Computational Seismology
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| Description |
Delhi, the capital of India, is prone to severe seismic
hazards, not only from local events but also from Himalayan
earthquakes at distances of 250–300 km. Standard techniques are
not sufficiently reliable to completely characterize the seismic
hazards in this case due to the difficulty of predicting the occurrence
of earthquakes (frequency–magnitude relations) and of
properly treating the propagation of their effects (attenuation laws),
especially their long-period components. In order to give a sound
description of the seismic ground motion due to an earthquake in
such a given range of distances (and magnitudes), we use modelling
techniques developed from physics of the seismic source
generation and propagation processes. Such models take into
account the directivity effect of rupture propagation and the
attenuation of (long-period) ground motions. The generated ground
motion scenarios permit us to build a very important knowledge
base to be fruitfully used by civil engineers, since long period
ground motions, especially if amplified by deep sedimentary
basins, can represent a severe threat for large scale structures (e.g.
lifelines and bridges) and tall buildings, which are widespread in
fast-growing megacities. In this study, we simulate the ground
motion, at bedrock level, in Delhi city, for an earthquake scenario
corresponding to a source of Mw = 8.0 located in the central
seismic gap of Himalayas, at an epicentral distance of about
300 km from Delhi city. By means of several parametric studies,
we simulate the time histories using Size Scaled Point Source,
Space and Time Scaled Point Source and Extended Source models.
Together with the complete time histories (displacements, velocities
and accelerations, from which the peak amplitudes have been
extracted), we have also used the displacement response spectrum
to characterize the seismic input at Delhi. Not only is the displacement
response spectrum of great significance to modern
displacement-based design engineering approaches, but it is
probably the best parameter by which to characterize the destructiveness
potential of earthquakes located at such great distances
from the target sites (of the order of 300 km), since the energy of
the seismic input is mainly concentrated at long periods (in general,
greater than 1 s) and it cannot be determined by straightforward
integration of velocity or acceleration response spectra.
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| Publisher |
Springer
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| Date |
2010-05-29
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://cir.cmmacs.ernet.in/46/1/parvez%20et%20al%20pageoph%2D2011.pdf
Parvez, Imtiyaz A (2010) Long Period Ground Motion at Bedrock Level in Delhi City from Himalayan Earthquake Scenarios. Pure and Applied Geophysics, 168 (3-4). pp. 409-477. ISSN 0033-4553 |
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| Relation |
http://www.springerlink.com
http://cir.cmmacs.ernet.in/46/ |
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