Study area

The Bangalore city covers an area of approximately 696.17 Sq. km (Greater Bangalore). The area of study is limited to Bangalore Metropolis area (Bangalore Mahanagar Palike) of about 220 sq.km. Bangalore is situated on a latitude of 12o 58' North and longitude of 77o 36' East and is at an average altitude of around 910 m above mean sea level (MSL). It is the principal administrative, industrial, commercial, educational and cultural capital of Karnataka state and lies in the South- Western part of India (see Figure 3.1). Bangalore city is the fastest grown city and fifth biggest city in India. Besides political activities, Bangalore possesses many national laboratories, defence establishments, small and large-scale industries and Information Technology Companies. These establishments have made Bangalore a very important and strategic city. It experiences temperate and salubrious climate and an annual rainfall of around 940 mm. There were over 150 lakes, though most of them are dried up due to erosion and encroachments leaving only 64 at present in an area of 220 sq km. These tanks were once distributed throughout the city for better water supply but presently in a dried up condition the residual silt and silty sand form thick deposits over which buildings/structures have been built, which are susceptible for site amplification.

Seismic Study Area

For the purpose of seismic hazard analysis, circular area with a radius of about 350km around Bangalore has been selected for the seismicity study as per Regulatory Guide 1.165(1997). Regional geological and seismological details for the Bangalore city were collected from literature review, study of maps and remote sensing data. The study area marked in the India map is shown in Figure 3.1. The geological study area having the center point as Bangalore city with a circular area of 350km radius (which covers the latitude 9.8o N to 16.2 o N and longitude of 74.5o E to 80.7o E). Geology of the study area is presented in the Seismotectonic Atlas of India (SEISAT, 2000) published by Geological Survey of India, is used here. Geological formation of the study area is similar to the Indian Peninsula, which is geologically considered as one of the oldest land masses of the earths crust. Tectonic/Geological map of the study area is shown in Figure 3.2. Most of the study area is classified as Gneissic complex/Gneissic granulite with major inoculation of greenstone and allied supracrustal belt, which are believed to have occurred between 3400 to 3000 million years ago giving rise to an extensive group of grey gneisses designated as the older gneiss complex. These gneisses act as the basement for a widespread belt of schists. The younger group of gneissic rocks mostly of granodiomitic and granitia composition is found in the eastern part of the state, representing remobilized parts of an older crust with abundant additions of newer granite material, for which the name younger gneiss complex was given (Radhakrishnan and Vaidyanadhan, 1997).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Department of Civil Engineering

Indian Institute of Science, Bangalore

Webpage is maintained by

Dr P Anbazhagan

Lecturer

Department of Civil Engg

Indian Institute of Science

Bangalore, India 560012

Suggestions and queries may be directed to Dr P Anbazhagan

Copyright  All Rights Reserved.

This page was last updated on August 25, 2011