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

Solution: It is assumed that the attenuation relationship given by Cornell at equation
(1) valid for the region. The peak ground acceleration to be expected at the site
corresponding to the maximum magnitude of an earthquake occurring at the sources
is given in Table below.
On the basis of Table 5.2, the hazard would be considered to be resulting
from an earthquake of magnitude 7.5 occurring from source 1. This hazard is
estimated as producing a PGA of 0.49g at the site.
Source M r(km) PGA(g)
1 7.5 23.70 0.490
2 6.8 60.04 0.10
3 5.0 78.63 0.015
Table 5.2 : PGA at the site for different sources
Intensity Calculation - Examples:
To estimate the intensity of the earthquake, following methodology is adopted :
� Step1: Divide the entire country in to ½ degree X ½ degree blocks. Each ½
degree block is 55 km X 55 km.
� Step 2: Plot all the historical earthquake of magnitude 5 and above in Richter
scale.
� Setp3: Use table 1.0 to estimate the intensity at epicenter ( Io)
� Step 4: Use the equation EQ 2.0 to estimate intensity in neighboring block(
Ix)
� Step 5: Plot all major earthquakes occurring in different blocks and estimate
the intensities in the surrounding blocks.
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