High Resolution 1:10,000 scale Mapping Strategy of Multi ... - NDMA

influencing factors are the properties of overlying soil layer over the bedrock., type of
rock bed and the depth of overlying soil. The summary of effects is as follows;
1. Attenuation of ground motion may be significant through the rock up to the
long distances from the epicenter.
2. Soil deposit may change the predominate period of seismic waves.
3. Duration of shaking considerably increases at site with soft soil deposit. sandy
soil layer causes amplification of PGA
4. Response spectrum narrows down over soft soil compare to bed rock.
5. Spectral amplification is more for soft soil compare to silt soil. For longer
period seismic waves(.5 to 2 seconds)
6. Amplification factor for PGA decreases at soil surface
SUMMARY OF EARTHQUAKE DATA
The earthquake data for last 200 years for the period 1800-2005 has been collected
from IMD catalogs, ISC bulletins and USGS publications. The total number of
earthquakes recorded in India and their neighborhoods are 10,376 with magnitude
4.0 and above on Richter scale mostly located on tectonics plate boundaries as
shown in seismicity map as above
Total numbers of earthquakes recorded in Indian territory are 3,968 with magnitude
4.0 and above. Total 152 devastating earthquakes with magnitude 6.0 and above
have occurred in India which shows the vulnerability of Indian landmass. Total 5
great earthquakes of magnitude 8.0 and above have occurred in MCT/MBT causing
significant damage. The possibility of occurrence of major earthquake in MCT/MBT in
near future can not be ruled out.
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