Evaluating the seismic hazard to the National Capital (Delhi) Region, India, from moderate earthquakes using simulated accelerograms

Dinesh Kumar (), Irene Sarkar (), V. Sriram () and S. Teotia

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards, 2012, vol. 61, issue 2, 500 pages

Abstract: The National Capital Region (NCR) of India is exposed to high seismic hazard and risk due to a great earthquake in the central seismic gap of Himalaya and/or due to moderate-size earthquake within NCR. The high population density, rapid growth of infrastructure, and old engineering structures in the region make it more vulnerable to the human as well as economic loss due to moderate-size earthquakes also. The evaluation of seismic hazard is the first step to prepare a proper mitigation plan for the region. The aim of this paper is to evaluate the seismic hazard and risk due to moderate-size earthquakes in the vicinity of NCR. For this purpose, a suit of accelerograms have been generated from hypothetical moderate-size earthquakes (M 5.5 and 6.0) in the region. A basic fault-plane solution is assumed for this purpose. The ranges of the different parameters like depth of focus and stress drop values have been used in order to examine the effect of these parameters on hazard. The accelerograms have been synthesized using two basic velocity models, one representing a hard site and the other a site with a significant low-velocity cover. These two velocity models represent the ridge area and trans-Yamuna river area in the NCR. The decay of peak ground acceleration (pga) values with distance is fast in trans-Yamuna region (with low-velocity surface layer of 100 m) as compared to that of ridge area (with low-velocity surface layer of 1 m). Also, the decay of pga becomes slower if we increase the depth of focus from 10 to 20 km. The response spectra (5% damping) of the synthetic accelerograms for the three periods T = 0.4s, 0.75s, and 1.25s have been estimated and presented in the form of decay curves. The amplifications as a function of epicentral distance and stress drop have also been estimated. We note that the amplifications in 100-m layer case do not occur uniformly at all the distances, rather it is dependent on the angle of incidence of energy into the layers. The pga values are generally amplified by more than twice with increase in stress drop from 100 to 400 bars. The seismic exposure of the population in Delhi city has been presented. The results presented in this study may serve as an important input in the planning of mitigation and disaster management programs in the National Capital Region. Copyright Springer Science+Business Media B.V. 2012

Keywords: Composite source model; Accelerogram; Simulation; Seismic hazard (search for similar items in EconPapers)
Date: 2012
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://hdl.handle.net/10.1007/s11069-011-9933-2 (text/html)
Access to full text is restricted to subscribers.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:nathaz:v:61:y:2012:i:2:p:481-500

Ordering information: This journal article can be ordered from
http://www.springer.com/economics/journal/11069

DOI: 10.1007/s11069-011-9933-2

Access Statistics for this article

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards is currently edited by Thomas Glade, Tad S. Murty and Vladimír Schenk

More articles in Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards from Springer, International Society for the Prevention and Mitigation of Natural Hazards
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().