Page 9 - EQTips_Eng

IITK-BMTPC Earthquake Tip 4

Where are the Seismic Zones in India? page 2
Table 1: Some Past Earthquakes in India seismic zone map in 1962, which was later revised in
Max. 1967 and again in 1970. The map has been revised
Date Event Time Magnitude Deaths
Intensity again in 2002 (Figure 4), and it now has only four
16 June 1819 Cutch 11:00 8.3 VIII 1,500 seismic zones – II, III, IV and V. The areas falling in
12 June 1897 Assam 17:11 8.7 XII 1,500
8 Feb. 1900 Coimbatore 03:11 6.0 X Nil seismic zone I in the 1970 version of the map are
4 Apr. 1905 Kangra 06:20 8.6 X 19,000 merged with those of seismic zone II. Also, the seismic
15 Jan. 1934 Bihar-Nepal 14:13 8.4 X 11,000 zone map in the peninsular region has been modified.
31 May 1935 Quetta 03:03 7.6 X 30,000 Madras now comes in seismic zone III as against in
15 Aug. 1950 Assam 19:31 8.5 X 1,530 zone II in the 1970 version of the map. This 2002
21 Jul. 1956 Anjar 21:02 7.0 IX 115 seismic zone map is not the final word on the seismic
10 Dec. 1967 Koyna 04:30 6.5 VIII 200 hazard of the country, and hence there can be no sense
23 Mar. 1970 Bharuch 20:56 5.4 VII 30
21 Aug. 1988 Bihar-Nepal 04:39 6.6 IX 1,004 of complacency in this regard.
20 Oct. 1991 Uttarkashi 02:53 6.6 IX 768
30 Sep. 1993 Killari (Latur) 03:53 6.4 IX 7,928
22 May 1997 Jabalpur 04:22 6.0 VIII 38
29 Mar. 1999 Chamoli 12:35 6.6 VIII 63
26 Jan. 2001 Bhuj 08:46 7.7 X 13,805
26 Dec. 2004 Sumatra 06:28 9.3 VII 10,749
The timing of the earthquake during the day and
during the year critically determines the number of
casualties. Casualties are expected to be high for
earthquakes that strike during cold winter nights,
when most of the population is indoors.
Seismic Zones of India
The varying geology at different locations in the
country implies that the likelihood of damaging
earthquakes taking place at different locations is
different. Thus, a seismic zone map is required to
identify these regions. Based on the levels of intensities
sustained during damaging past earthquakes, the 1970 Figure 4: Indian Seismic Zone Map as per

version of the zone map subdivided India into five IS:1893 (Part 1)-2002

zones – I, II, III, IV and V (Figure 3). The maximum
Modified Mercalli (MM) intensity of seismic shaking The national Seismic Zone Map presents a large-
expected in these zones were V or less, VI, VII, VIII, scale view of the seismic zones in the country. Local
and IX and higher, respectively. Parts of Himalayan variations in soil type and geology cannot be
boundary in the north and northeast, and the Kachchh represented at that scale. Therefore, for important
area in the west were classified as zone V. projects, such as a major dam or a nuclear power plant,
the seismic hazard is evaluated specifically for that
site. Also, for the purposes of urban planning,
metropolitan areas are microzoned. Seismic
microzonation accounts for local variations in geology,
local soil profile, etc,.
Reading Material
BMTPC, (1997), Vulnerability Atlas of India, Building Materials and
Technology Promotion Council, Ministry of Urban Development,
Government of India, New Delhi
Dasgupta,S., et al, (2000), Seismotectonic Atlas of Indian and its
Environs, Geological Survey of India
IS:1893, (1984), Indian Standard Criteria for Earthquake Resistant
Design of Structures, Bureau of Indian Standards, New Delhi

Authored by:
C.V.R.Murty
Indian Institute of Technology Kanpur
Kanpur, India
Sponsored by:

Figure 3: Indian Seismic Zone Map of 1970 Building Materials and Technology Promotion
Council, New Delhi, India
The seismic zone maps are revised from time to
time as more understanding is gained on the geology, This release is a property of IIT Kanpur and BMTPC New
the seismotectonics and the seismic activity in the Delhi. It may be reproduced without changing its contents
and with due acknowledgement. Suggestions/comments
country. The Indian Standards provided the first may be sent to: nicee@iitk.ac.in. Visit www.nicee.org or
www.bmtpc.org, to see previous IITK-BMTPC Earthquake Tips.
8