Lok Sabha Question No. 581 (UNSTARRED), answered on 2015-12-02
Subject: Frequency of Earthquakes
Ministry: EARTH SCIENCES
Asked by: MAJ. GEN. (RETD) BHUWAN CHANDRA KHANDURI AVSM

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOK SABHA

## UNSTARRED QUESTION No. 581 TO BE ANSWERED ON WEDNESDAY, DECEMBER 02, 2015

## FREQUENCY OF EARTHQUAKES

581.   MAJ GEN B.C. KHANDURI AVSM (Retd):

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) the  frequency  with  which  earthquakes  are  being  experienced  in  the country;
- (b) whether  many  cities  in  the  country  particularly  in  Uttarakhand  is  in high  seismic  zone  and  may  receive  earthquakes  of  high  intensity causing large scale devastation;
- (c) if so, the details thereof; and
- (d) the steps taken by the Government to ensure that damage is minimized in case of earthquakes of high intensity?

## ANSWER

## MINISTER OF STATE FOR MINISTRY OF SCIENCE AND TECHNOLOGY AND MINISTRY OF EARTH SCIENCES (SHRI Y. S. CHOWDARY)

- (a) Analysis of past 30 years of earthquake data suggests that there is no increase or decrease in seismic rate. Based on frequency of earthquake (seismicity), maximum intensities experienced in the past and the Seismotectonics of the region, Bureau of Indian Standard [IS 1983 (Part I):2002] has grouped the country into four seismic zones viz. Zone-II, Zone-III, Zone-IV and Zone-V. Of these, Zone V is seismically the most prone region with higher incidence of activities of earthquakes and Zone II is the least prone region with lower incidents of activities of earthquakes.

The  Modified  Mercalli  (MM)  intensities,  which  measure  the  impact  of the  earthquakes  on  the  surface  of  the  earth,  are  broadly  associated with aforesaid four seismic zones as detailed below:

## Seismic Zone

Intensity on MM scale

II   (Low intensity zone)

VI (or less)

III   (Moderate intensity zone)

VII

IV   (Severe intensity zone)

VIII

V   (Very severe intensity zone)

IX (and above)

- (b-c)   Cities/States of northern and North-eastern parts of India are falling in the seismic zones V and IV and are thus grouped under high intensity seismic  zone  and  so  is  the  Uttarakhand.  Earthquake  in  such  regions may  cause  considerable  damage  in  the  epicentral  and  adjoining regions. List of states falling under various categories of seismic zones are presented in the Annexure-I.
- (d) Bureau of Indian Standards (BIS) has published several guidelines and building codes for construction of earthquake resistant structures and for  retrofitting  of  existing  buildings.  These  guidelines  are  in  wide circulation  amongst  the  public  and  the  administrative  authorities responsible  for  the  design  and  construction  of  earthquake  resistant structures in earthquake prone areas.

National  Disaster  Management  Authority  (NDMA),  Ministry  of  Home Affairs  (MHA),  Ministry  of  Earth  Sciences  and  other  state  Disaster Management  Authorities,  have  also  taken  up  various  initiatives  to educate  and  enhance  awareness  amongst  general  public  and  school children  on  the  general  aspects  of  earthquakes,  their  impacts  and measures  to  mitigate  losses  caused  by  them.  A  National  Disaster Response Force (NDRF) is also functional under the general superintendence, direction and control of the NDMA for the purpose of specialized response to natural and man-made disasters.

## Seismic Zones vis-a-vis Regions in India

| Seismic Zone                                         | Region                                                                                                                                                                                                                                                      |
|------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Zone - V [highest active (most severe) seismic zone] | Entire north eastern States of India, parts of Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Rann of Kutch in Gujarat, part of North Bihar and Andaman & Nicobar Islands.                                                                               |
| Zone - IV [high active (severe) seismic zone]        | Remaining parts of Jammu and Kashmir and Himachal Pradesh, National Capital Territory (NCT) of Delhi, Sikkim, Northern Parts of Uttar Pradesh, Bihar and West Bengal, parts of Gujarat and small portions of Maharashtra near the west coast and Rajasthan. |
| Zone - III [moderately active seismic zone]          | Kerala, Goa, Lakshadweep islands, remaining parts of Uttar Pradesh, Gujarat and West Bengal, Parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Maharashtra, Orissa, Andhra Pradesh, Tamilnadu and Karnataka.                      |
| Zone - II [least active seismic zone]                | Remaining parts of the country.                                                                                                                                                                                                                             |

## Annexure-I