A source and ground motion study of earthquakes in and near Delhi (the National Capital Region), India
Por:
Bansal, Brijesh K., Singh, S. K., Suresh, G., Mittal, H.
Publicada:
1 mar 2022
Ahead of Print:
1 nov 2021
Resumen:
We study source parameters of 10 local earthquakes (2.7 <= M-w <= 4.5)
that have occurred in the National Capital Region (NCR) since 2001 and
the ground motions produced by these events. Moment rate spectra of the
earthquakes retrieved from the recordings at hard sites after applying
corrections for geometrical spreading (1/R, R <= 100 km), anelastic
attenuation (Q = 253f(0.8)) and cutoff frequency (f(m) = 35 Hz) are
reasonably well fit by the Brune omega(2)-source model with stress drop
ranging between 0.9 and 13 MPa. Neglecting the out-lier low-stress drop
value, the average stress drop is 6 MPa. We apply a modified standard
spectral ratio technique to estimate site effect at 38 soft sites in the
NCR as well as the geometrical mean site effect with respect to a
reference hard site. Application of the stochastic method, with source
characterized by the Brune omega(2)- model with stress drop of 6 MPa and
the mean site effect for soft sites, yields peak horizontal ground
acceleration and velocity curves that are in good agreement with the
observed values. These results provide the parameters needed for the
application of the stochastic method to predict ground motions at hard
and soft sites in the NCR during postulated M-w <= 5.5 earthquakes.
Filiaciones:
Bansal, Brijesh K.:
Minist Earth Sci, Natl Ctr Seismol, New Delhi, India
Indian Inst Technol Delhi, New Delhi, India
Singh, S. K.:
Univ Nacl Autonoma Mexico, Mexico City, DF, Mexico
Suresh, G.:
Minist Earth Sci, Natl Ctr Seismol, New Delhi, India
Mittal, H.:
Minist Earth Sci, Natl Ctr Seismol, New Delhi, India
Green Published, Bronze, Green
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