PRELIMINARY SEISMIC HAZARD MAP OF PENINSULAR INDIA

This paper presents the detailed seismic hazard assessment of the peninsular India (lat. 8°-28°N and long. 67.5°-90°E) which is considered to be seismically most stable landmasses of the Indian plate. Past seismic history in this region (Koyna, etc) clearly shows that the seismicity of the area is varying. There were more than five damaging earthquakes with magnitudes greater than M w 6.0 have occurred in this region, stressing the importance of detailed seismic hazard assessment for the region. For India, published a probabilistic seismic hazard map based on several well identified and prominent source zones in the country. An attempt has been made in this paper to study the present seismic status of this region incorporating the seismicity, tectonic and geological characteristics and using the collected earthquake data Peak Ground Acceleration was estimated using the attenuation relation developed by Iyengar and Raghukanth (2004). Estimated PGA values were used to compute the deviation with respect to assigned PGA values for various regions provided in Indian Standard code IS 1893:2002. The results show that, the estimated PGA in many areas of the Peninsular India is more than the specified value in the current seismic macrozonation map of the country. This provides an important basis for attempting the detailed microzonation of an area within the Penisular India.

This paper presents the detailed seismic hazard assessment of the peninsular India (lat. 8°-28°N and long. 67.5°-90°E) which is considered to be seismically most stable landmasses of the Indian plate. Past seismic history in this region (Koyna, etc) clearly shows that the seismicity of the area is varying. There were more than five damaging earthquakes with magnitudes greater than Mw 6.0 have occurred in this region, stressing the importance of detailed seismic hazard assessment for the region. For India, published a probabilistic seismic hazard map based on several well identified and prominent source zones in the country. An attempt has been made in this paper to study the present seismic status of this region incorporating the seismicity, tectonic and geological characteristics and using the collected earthquake data Peak Ground Acceleration was estimated using the attenuation relation developed by Iyengar and Raghukanth (2004). Estimated PGA values were used to compute the deviation with respect to assigned PGA values for various regions provided in Indian Standard code IS 1893:2002. The results show that, the estimated PGA in many areas of the Peninsular India is more than the specified value in the current seismic macrozonation map of the country. This provides an important basis for attempting the detailed microzonation of an area within the Penisular India.

Journal of Earth System Science, 2008

This paper examines the variability of seismic activity observed in the case of different geological zones of peninsular India (10 • N-26 • N; 68 • E-90 • E) based on earthquake catalog between the period 1842 and 2002 and estimates earthquake hazard for the region. With compilation of earthquake catalog in terms of moment magnitude and establishing broad completeness criteria, we derive the seismicity parameters for each geologic zone of peninsular India using maximum likelihood procedure. The estimated parameters provide the basis for understanding the historical seismicity associated with different geological zones of peninsular India and also provide important inputs for future seismic hazard estimation studies in the region. Based on present investigation, it is clear that earthquake recurrence activity in various geologic zones of peninsular India is distinct and varies considerably between its cratonic and rifting zones. The study identifies the likely hazards due to the possibility of moderate to large earthquakes in peninsular India and also presents the influence of spatial rate variation in the seismic activity of this region. This paper presents the influence of source zone characterization and recurrence rate variation pattern on the maximum earthquake magnitude estimation. The results presented in the paper provide a useful basis for probabilistic seismic hazard studies and microzonation studies in peninsular India.

Geophysical Journal International, 2003

A seismic hazard map of the territory of India and adjacent areas has been prepared using a deterministic approach based on the computation of synthetic seismograms complete with all main phases. The input data set consists of structural models, seismogenic zones, focal mechanisms and earthquake catalogues. There are few probabilistic hazard maps available for the Indian subcontinent, however, this is the first study aimed at producing a deterministic seismic hazard map for the Indian region using realistic strong ground motion modelling with the knowledge of the physical process of earthquake generation, the level of seismicity and wave propagation in anelastic media. Synthetic seismograms at a frequency of 1 Hz have been generated at a regular grid of 0.2°× 0.2° by the modal summation technique. The seismic hazard, expressed in terms of maximum displacement (Dmax), maximum velocity (Vmax), and design ground acceleration (DGA), has been extracted from the synthetic signals and mapped on a regular grid over the studied territory. The estimated values of the peak ground acceleration are compared with the observed data available for the Himalayan region and are found to be in agreement. Many parts of the Himalayan region have DGA values exceeding 0.6 g. The epicentral areas of the great Assam earthquakes of 1897 and 1950 in northeast India represent the maximum hazard with DGA values reaching 1.2-1.3 g. The peak velocity and displacement in the same region is estimated as 120-177 cm s-1 and 60-90 cm, respectively.

Geomatics, Natural Hazards and Risk, 2013

Earthquakes constitute among the most feared natural hazards and these occur with no warning which can result in great destruction and loss of lives, particularly in developing countries. One way to mitigate the destructive impact of such earthquakes is to conduct a seismic hazard assessment and take remedial measures. This article aims at demonstrating significant contributions in the field of seismic zonation and microzonation studies in the Indian subcontinent. The contributions in the field of earthquake hazard have been very valuable and beneficial not only for science but also for society. The historical seismicity and seismic zonation studies as well as the present scenario of seismic hazard assessment in the Indian subcontinent, whether through probabilistic or deterministic approaches, are discussed. It has been found that many parts of the Himalayan region have peak acceleration values exceeding 0.6g. The epicentral areas of the great Assam earthquakes of 1897 and 1950 in northeast India represent the maximum hazard with acceleration values reaching 1.2-1.3g. The peak velocity and displacement in the same region is estimated as 120-177 cm s 71 and 60-90 cm, respectively. To mitigate seismic risk, it is necessary to define a correct response in terms of both peak ground acceleration and spectral amplification. These factors are highly dependent on local soil conditions and on the source characteristics of the expected earthquakes. This article will also present the findings of site-specific hazard assessment in megacities.

Bulletin of the Seismological Society of …, 2007

Peninsular India (10.0° N–28.0° N; 68.0° E–90.0° E) is one of the oldest and seismically most stable landmasses of the Indian plate. Recent seismic history, however, shows that more than five damaging earthquakes with magnitudes greater than M w 6.0 have occurred in this ...

Many earthquakes have been knowledgeable in Indian peninsular shield, which was previously treated to be seismically steady. Seismic risk assessment refers to an evaluation of ground motion parameters at a particular area by considering some past earthquake evidence. In the current study seismic risk assessment is performed for the " Gorakhpur " city. It is a highly seismic prone area. It comes under zone IV. The manuscript presents the resolve of peak ground acceleration (PGA) and maximum credible earthquake (MCE). MCE has been dogged by taking into account the local seismotectonic movement in a propos 350 km radius about Gorakhpur city. The seismic risk in provisions of peak horizontal acceleration was estimated to be 0.312g using attenuation model by " Sharma " (2000) and 0.032g using attenuation model by " Iyenger and Raghukanth " (2004). The calculated peak horizontal acceleration in the nearby reading is in verification with the observed values of Nepal earthquakes and is furthermore similar to standards reported in additional studies.

Geoscience Frontiers, 2014

Pure and Applied Geophysics, 1997

The Indian subcontinent is one of the most seismic prone areas of the world. The Himalayan mountains in the north, mid-oceanic ridges in the south and earthquake belts surrounding the Indian plate all show that the subcontinent has undergone extensive geological and tectonic processes in the past. The probability of the occurrence of earthquakes with magnitude 6 BM b B7 during a specified interval of time has been estimated on the basis of four probabilistic models namely Lognormal, Weibull, Gamma and Exponential distribution for the Indian subcontinent. The seismicity map has been prepared using the earthquake catalogue from the period 1963 -1994, and six different zones have been identified on the basis of clustering of events. The model parameters have been estimated by the method of maximum likelihood estimates (MLE) and method of moments (MOM). A computer program package has been developed for all four models, which represents the distributions of time intervals fairly well. The logarithmic of likelihood (ln L) is estimated for testing the models and different models have been found to be plausible. The probability of different magnitude thresholds has been evaluated using the Gutenberg-Richter formula Log N= a −bM for magnitude distribution. The constants a and b have been computed for each region and found to be varying between 5.46 -8.53 and 0.87-1.34, respectively.

MOJ Civil Engineering

Earthquakes, the most dangerous and destructive natural hazards in the globe, manifest themselves in the form of vibrations of the earth which are caused by the sudden release of strain that has accumulated over time. Recent years have witnessed an increase in awareness about earthquake and their causes and mitigations. Seismic Hazard analysis is a method of quantifying the area in terms of topographical and seismological data. In the present paper, an attempt has been made to estimate seismic hazard at bedrock level in terms of PGA using state of art, probabilistic seismic hazard analysis. A detailed catalogue of historical and recent seismicity, within 300 km radius around the headquarter has been compiled and new seism tectonic map has been generated for the region. The completeness of the data should be checked before carrying out hazard analysis. Finally earthquake data analyzed statistically and the seismicity of the region around district headquarter Dantewara of Chhattisgarh, India, has been evaluated by defining 'a' and 'b' parameters of Gutenberg-Richter recurrence relationship. For district headquarter Dantewara, Values of the Peak Ground Acceleration (P.G.A.) for M100 Earthquake, has been estimated. The outcome of the research in the present paper, clearly indicate that the maximum (Peak Ground Acceleration) PGA values for the site of Dantewara, was obtained, due to fault No. 8.