Seismic Zonation of the Delhi Region for Bedrock Ground Motion

Sharma, M. L.; Wason, H. R.; Dimri, R.

doi:10.1007/s00024-003-2400-6

Cited by 52 publications

(22 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is, therefore, imperative to state that the PSHA for seismic microzonation at the bedrock level is more important for urban or developing cities. SHARMA et al (2003) evaluated the seismic zonation of the Delhi region for Bedrock ground motion. JAISWAL and SINHA (2007) carried out the bedrock PGA for Peninsular India through the Probabilistic method using regional sources for the larger area.…”

Section: Resultsmentioning

confidence: 99%

A New Insight into Probabilistic Seismic Hazard Analysis for Central India

Mandal

Shukla

Khan

et al. 2013

Pure Appl. Geophys.

View full text Add to dashboard Cite

Abstract-The Son-Narmada-Tapti lineament and its surroundings of Central India (CI) is the second most important tectonic regime following the converging margin along HimalayasMyanmar-Andaman of the Indian sub-continent, which attracted several geoscientists to assess its seismic hazard potential. Our study area, a part of CI, is bounded between latitudes 18°-26°N and longitudes 73°-83°E, representing a stable part of Peninsular India. Past damaging moderate magnitude earthquakes as well as continuing microseismicity in the area provided enough data for seismological study. Our estimates based on regional GutenbergRichter relationship showed lower b values (i.e., between 0.68 and 0.76) from the average for the study area. The Probabilistic Seismic Hazard Analysis carried out over the area with a radius of *300 km encircling Bhopal yielded a conspicuous relationship between earthquake return period (T) and peak ground acceleration (PGA). Analyses of T and PGA shows that PGA value at bedrock varies from 0.08 to 0.15 g for 10 % (T = 475 years) and 2 % (T = 2,475 years) probabilities exceeding 50 years, respectively. We establish the empirical relationships ZPA These demonstrate that the ZPA values decrease with increasing shear wave velocity, suggesting a diagnostic indicator for designing the structures at a specific site of interest. The predictive designed response spectra generated at a site for periods up to 4.0 s at 10 and 2 % probability of exceedance of ground motion for 50 years can be used for designing duration dependent structures of variable vertical dimension. We infer that this concept of assimilating uniform hazard response spectra and predictive design at 10 and 2 % probability of exceedance in 50 years at 5 % damping at bedrocks of different categories may offer potential inputs for designing earthquake resistant structures of variable dimensions for the CI region under the National Earthquake Hazard Reduction Program for India.

show abstract

Section: Resultsmentioning

confidence: 99%

A New Insight into Probabilistic Seismic Hazard Analysis for Central India

Mandal

Shukla

Khan

et al. 2013

Pure Appl. Geophys.

View full text Add to dashboard Cite

show abstract

“…Most of the seismic hazard studies of the Delhi region have been presented in terms of peak ground acceleration (PGA) using various ground-motion prediction equations (GMPEs). PGA values for 475 years of return period estimated by Agrawal and Chawla (2006) are reported to be in the range of 0.12-0.17 g and by Sharma et al (2003) for 225 years of return period between 0.15 and 0.34 g. Iyengar and Ghosh (2004) estimated the PGA values for 2,500 years of return period between 0.18 and 0.24 g, which is the highest in the north-west part of Delhi. Apart from these seismic microzonation of Delhi have been reported by different researcher includes ground shaking site-effects by Mukhopadhyay et al (2002), site-specific Microzonation study in Delhi Metropolitan city by 2-D modelling of SH and P-SV waves by Parvez et al (2004), microzonation of earthquake hazard in Greater Delhi area by Iyengar and Ghosh (2004), and seismic microzonation studies for Delhi Region by Rao and Satyam (2005) and first-order seismic microzonation map of Delhi using GIS by Mohanty et al (2007).…”

Section: Introductionmentioning

confidence: 92%

“…The RGBF represents a 10-20-km-wide zone and demarcates the interface between the Vindhyan supergroup of rocks on the eastern side and the Aravalli supergroup of rocks on the western side. The earthquake of 31 August 1803 near Mathura is associated with this zone in addition to its The earthquake source models considered in the past have been mostly the Line Source models (Sharma et al 2003;Iyengar and Ghosh 2004). The errors in location of earthquakes and the mapping of seismogenic sources geophysically make it imperative to use area sources.…”

Section: Seismotectonic Modelling Of the Regionmentioning

confidence: 99%

Strong ground-motion prediction and uncertainties estimation for Delhi, India

Joshi

Sharma

2011

Nat Hazards

Self Cite

View full text Add to dashboard Cite

An endeavour has been made in the present study to estimate the uncertainties in strong ground-motion estimation for Delhi region. The strong ground motion (SGM) has been estimated using the logic-tree approach with equal weights chosen for the branches of the logic tree because a scientific preference has not yet been developed for the area. Coefficient of variation (COV) maps have been generated along with the mean SGM which aid in visualizing the effect of our lack of knowledge on the final results and highlight those areas where improved scientific understanding can have an impact on future hazard maps. Monte Carlo simulation has been sued to consider the effect of the variation in the seismic hazard parameters. The spectral ground generated for various return periods suggests higher values in the north-west region with a decreasing trend towards the south-east part of Delhi. The hazard gradient is highest at spectral acceleration (Sa) 0.1 s and lowest at spectral acceleration (Sa) 1.0 s for all return periods. The highest COV values (*0.60) were observed in case of PGA while lowest COV values (*0.15) were observed for spectral acceleration (Sa) 0.3 s at all return periods. One of the conspicuous observations is that the trends of COV maps have been found to be governed by the boundaries of the seismogenic sources. While COV values are governed mostly by Line Sources in smaller return and time periods, in higher return periods trend of the COV maps were found to be governed by the boundaries of the Areal Sources.

show abstract

“…Most of the seismic hazard studies involved the estimation of peak ground acceleration (PGA) using various ground motion prediction equations (GMPEs). PGA values for 475 years of return period estimated by Agrawal and Chawla (2006) were reported to be in the range of 0.12-0.17 g and by Sharma et al (2003) for 225 years of return period between 0.15 and 0.34 g. Iyengar and Ghosh (2004) estimated the PGA values for 2,500 years of return period between 0.18 and 0.24 g, which was the highest in the northwest part of Delhi. Apart from these studies, informations involving the ground shaking site-effects studies by Mukhopadhyay et al (2002), site-specific microzonation study through 2D modeling of SH and P-SV waves by Parvez et al (2004), estimation of earthquake hazard in Greater Delhi area by Iyengar and Ghosh (2004), seismic microzonation studies by Rao and Satyam (2005), and first-order seismic microzonation map using GIS by Mohanty et al (2007) provided extensive database for seismic hazard assessment for Delhi and adjoining regions.…”

Section: Introductionmentioning

confidence: 93%

Soil responses near Delhi ridge and adjacent regions in Greater Delhi during incidence of a local earthquake

2012

View full text Add to dashboard Cite

In this study, soil response was carried out for the Greater Delhi region. A folded Proterozoic formation was identified as Delhi ridge, passes through its central part along SSW-NNE direction, and appears to be a main geomorphic feature for the study area. The Delhi ridge is an exposed quartzite rock of about 10-100 m wide and *25 km long with gentler dipping both toward east and west. We have considered the exposed part as an outcrop side near the ridge axis and the dipping area as rigid base away from the ridge axis for ground motion study during the occurrence of the 25 November 2007 earthquake with magnitude M L 4.3 (Richter scale) that occurred at Delhi-Haryana State boundary. The degree of shaking was very strong and reported major cracks in the buildings near the epicenter area. We have studied the soil response parameters at the surface level, considering horizontally stratified soil layers above rigid base. The equivalent linear method was used for soil response analysis at 25 sites in Greater Delhi area. The peak amplification factors vary from 3.2 to 5.9 and peak resonance frequency varies from 1.2 to 5.3 Hz. The correlation among the peak amplification factor (A) and frequency (f) was empirically established as A = 0.36f ? 3.60. Increasing peak amplification factor was found at sites with increasingly thicker alluvium deposit with lower frequency contains ground motion and vice versa. Seismic zoning map was also reconstructed for peak amplification factors and predominant periods for the study area for the mitigation purposes of earthquake damage. The average shear wave velocity up to 30 m soil depth is also obtained for site classification. The average velocity to 30 m [V s ð30Þ] is a widely used parameter for classifying sites for predicting their potentiality to amplify seismic shaking. A lower value [V s ð30Þ] thus yields a more conservative estimate of ground motion, which generally increases as V s ð30Þdecreases. Present estimate of V s ð30Þvaries from 315 to 419 m/s. In this study, we have identified two site classes C and D, as per National Earthquake Hazard Reduction Program. The city planner or engineers can directly use these data for site-specific assessment during retrofitting of the existing structure, 123Nat Hazards (2014) 70:93-118 DOI 10.1007 demolition of the old buildings and design a new structure to avoid major destruction of the buildings due to future earthquake.

show abstract

Seismic Zonation of the Delhi Region for Bedrock Ground Motion

Cited by 52 publications

References 13 publications

A New Insight into Probabilistic Seismic Hazard Analysis for Central India

A New Insight into Probabilistic Seismic Hazard Analysis for Central India

Strong ground-motion prediction and uncertainties estimation for Delhi, India

Soil responses near Delhi ridge and adjacent regions in Greater Delhi during incidence of a local earthquake

Contact Info

Product

Resources

About