Site Effects in Ahemdabad Based on Array Observations of Microtremors
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Title |
Site Effects in Ahemdabad Based on Array Observations of Microtremors
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| Creator |
Parvez, Imtiyaz A
Jade, Sridevi |
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| Subject |
Computational Seismology
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| Description |
The spate of Earthquakes in the country has heightened the sensitivity of administrators, engineers and even lay people to risks due to earthquakes. On January 26, 2001, one of the most destructive earthquakes ever to strike India occurred in the Kachchh region of Gujarat in western India. The earthquake of magnitude 7.7 (Mw) recorded at 8.46 am and damage was spread over a radius of 400 kilometers including major cities like Ahmedabad, Bhavnagar and Surat at a distance of 240 km, 275 km and 350 km respectively. Ahmedabad experienced significant damage to about 130 reinforced concrete frame buildings in the form of collapses. The city like Ahmedabad, located almost 250 km from the epicenter, getting the damage of the order of intensity VII is another example of a great role of site response due to surface geology like in Mexico, Kobe, Loma Prieta, Izmit and many others. Having a very long series of aftershocks (more than a year), very recently on August 6, 2003, there was a moderate earthquake of magnitude 4.9 in Kachchh near Rapar felt in Ahmedabad as well.
Ahmedabad, a city of historical value and one of the most industrial and economically developed cities of India is still under threat of ongoing seismic activities of Kachchh zone. A detailed site-characterization is a key for assessing the seismic hazard and S-wave velocity structure at a site is the most fundamental and quantitative parameter for estimating severity of earthquake ground motion. These results would then be used to simulate the strong ground motion to prepare a detailed microzonation map of the entire city. In the present project, it is proposed to carry out array observations of microtremors at several sites in Ahmedabad city using portable instruments developed for temporal observations of ambient noise. The generated data will then be used to analyse the site-effect and S-velocity structure using SPAC coefficients and phase velocity dispersions of Rayleigh waves. Geotechnical data will be used to constrain the results and Strong Ground Motion will also be simulated for the earthquake source of Kachchh zone using the detailed information of subsurface geology. At the conclusion of the project, maps of various seismic hazard parameters, directly measured or numerically modelled, notably of peak ground velocity and acceleration, that from the basic quantities for the design of earthquake-resistant structures will be produced. The instrument will further be used to repeat the study in other urban areas under seismic threat like Bangalore, Guwahati etc.
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| Publisher |
CSIR Centre for Mathematical Modelling and Computer Simulation
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| Date |
2003-09
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| Type |
Monograph
NonPeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://cir.cmmacs.ernet.in/257/1/PP%20CM%200302%20.pdf
Parvez, Imtiyaz A and Jade, Sridevi (2003) Site Effects in Ahemdabad Based on Array Observations of Microtremors. Other. CSIR Centre for Mathematical Modelling and Computer Simulation , C-MMACS,Bangalore 560037,India. (Unpublished) |
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| Relation |
http://cir.cmmacs.ernet.in/257/
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