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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/6550
Title: Delhi earthquake of 25 November 2007 (Mw 4.1): Implications for seismic hazard
Authors: Singh S.K.
Kumar A.
Suresh G.
Ordaz M.
Pacheco J.F.
Sharma, Mukat Lal
Bansal B.K.
Dattatrayam R.S.
Reinoso E.
Published in: Current Science
Abstract: The Delhi earthquake of 25 November 2007 (Mw 4.1) is the best recorded local event ever. Peak ground acceleration (PGA) at seven sites in the epicentral zone ranged between 7 and 118 Gal. An analysis of the earthquake leads to the following conclusions. (1) It occurred at a depth of 30 km and involved strike-slip faulting with some normal component, as against thrust faulting with minor strike-slip component previously reported for the region. (2) Observed PGA of this earthquake is poorly explained by the attenuation relation that has been used in the seismic hazard estimation of the Delhi region. This relation is also inconsistent with data from well-recorded Himalayan arc earthquakes. (3) Recordings from the 2007 earthquake reconfirm that there is a large and variable site effect in Delhi which differs significantly from that estimated from bore-hole penetration test data. These results, together with those from a previous study of two small events in Delhi, and an examination of the seismicity of the region, lead us to conclude that our present knowledge of seismotectonics and seismic hazard of Delhi is fraught with uncertainty, emphasizing an urgent need for improved and enlarged seismic instrumentation.
Citation: Current Science (2010), 99(7): 939-947
URI: http://repository.iitr.ac.in/handle/123456789/6550
Issue Date: 2010
Keywords: Attenuation relation
Delhi earthquake
Peak ground acceleration
Seismic hazard
Seismotectonics
ISSN: 113891
Author Scopus IDs: 57202910559
57203774508
57055243200
7004465619
35838606400
7403269008
7006107110
6505873296
6602584843
Author Affiliations: Singh, S.K., Instituto de Geofísica, UNAM, CU, 04510 México, DF, Mexico, Instituto de Ingeniería, UNAM, CU, 04510 México, DF, Mexico
Kumar, A., Department of Earthquake Engineering, Indian Institute of Technology, Roorkee 247 667, India
Suresh, G., India Meteorological Department, Lodhi Road, New Delhi 110 003, India
Ordaz, M., Instituto de Ingeniería, UNAM, CU, 04510 México, DF, Mexico
Pacheco, J.F., Instituto de Geofísica, UNAM, CU, 04510 México, DF, Mexico
Sharma, M.L., Department of Earthquake Engineering, Indian Institute of Technology, Roorkee 247 667, India
Bansal, B.K., Ministry of Earth Sciences, CGO Complex, Mahasagar Bhavan, New Delhi 110 003, India
Dattatrayam, R.S., India Meteorological Department, Lodhi Road, New Delhi 110 003, India
Reinoso, E., Instituto de Ingeniería, UNAM, CU, 04510 México, DF, Mexico
Corresponding Author: Singh, S.K.; Instituto de Geofísica, UNAM, CU, 04510 México, DF, Mexico; email: krishnamex@yahoo.com
Appears in Collections:Journal Publications [EQ]

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