Zone 5 covers the areas with the highest risks zone that suffers earthquakes of intensity MSK IX
or greater. The IS code assigns zone factor of 0.36 for Zone 5.
Structural designers use this factor for earthquake resistant design of
structures in Zone 5. The zone factor of 0.36 is indicative of effective
(zero period) peak horizontal ground acceleration of 0.36 g (36% of gravity) that may be generated during MCE level
earthquake in this zone. It is referred to as the Very High Damage Risk
Zone. The state of Kashmir ,the western and central Himalayas the North-East Indian region and the Rann of kutch fall in this zone.
This zone is called the High Damage Risk Zone and covers areas liable
to MSK VIII. The IS code assigns zone factor of 0.24 for Zone 4. The
Indo-Gangetic basin and the capital of the country (Delhi), Jammu and
Kashmir fall in Zone 4. In Maharashtra the Patan area (Koyananager) is
also in zone 4.
The Andaman and Nicobar island parts of kashmir ,
Western Himalayas fall under this zone. This zone is classified as
Moderate Damage Risk Zone which is liable to MSK VII. and also 7.8 The
IS code assigns zone factor of 0.16 for Zone 3.
This region is liable to MSK VI or less and is classified as the Low
Damage Risk Zone. The IS code assigns zone factor of 0.10 (maximum
horizontal acceleration that can be experienced by a structure in this
zone is 10% of gravitational acceleration) for Zone 2.