Lok Sabha Question No. 1663 (UNSTARRED), answered on 2023-12-13
Subject: Survey of Natural Disasters
Ministry: EARTH SCIENCES
Asked by: Pratibha Singh

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES

## LOK SABHA UNSTARRED QUESTION NO. 1663

## TO BE ANSWERED ON WEDNESDAY, 13 TH  DECEMBER, 2023

## SURVEY OF NATURAL DISASTERS

## 1663.       SHRIMATI PRATIBHA SINGH:

Will the Minister of Earth Sciences be pleased to state:

- (a) whether  the  Government  has  conducted  or  intends  to  conduct  any  study/survey  in respect  of  natural  disasters  such  as  landslides  and  avalanches  occurring  in  the  hilly areas including Himachal Pradesh;
- (b) if so, the details thereof;
- (c) whether any classification of such hazardous terrain locations has been made for the purpose  of  taking  preventive  measures  and  any  system  is  in  place  to  identify  such potential locations effectively; and
- (d) if so, the details thereof?

## ANSWER THE MINISTER OF EARTH SCIENCES

## (SHRI KIREN RIJIJU)

- (a) & (b)    Yes Sir. Geological Survey of India (GSI) under the administrative control of Ministry of Mines as the Nodal agency for landslide studies has been conducting investigations and Survey on various domains of landslide studies.

Under  landslide  studies,  regular  major  activities  of  GSI  are  conducted  every  year under Pre-disaster studies (multi-scale landslide susceptibility mapping and conducting landslide awareness programme); Post-disaster studies (landslide inventory mapping  and  detailed  site  specific  mapping,  slope  stability  analysis  and  landslide monitoring), and Regional landslide forecasting.

GSI launched the National Landslide Susceptibility Mapping (NLSM) Programme in 2014-15  for  generating  the  baseline  data  on  1:  50,000  scale  and  completed  the landslide susceptibility mapping of 4.3lakh sq.km of the landslide prone areas in India which  includes  approx.  42093  sq.km  area  in  Himachal  Pradesh.  The  landslide Susceptibility  Map classified  landslide  prone hilly  terrains  of  the  country  into  High, Moderate and Low zones based on proneness to land sliding. Under this programme, GSI  also  mapped  historical  87,230  nos.  of  landslide  polygon  using  both  remote sensing  (RS)  and  field-based  source  data,  out  of  which,  30,881  landslides  are  field validated.  Out  of  the  total  number  of  landslide  incidents,  17,102  landslide  incidents have  been  recorded  in  Himachal  Pradesh.  This  huge  historical  national  landslide inventory is continuously  being updated with the new landslide data collected  year- wise  as  part  of  Post-disaster  studies.  The  landslide  susceptibility  maps  and  the landslide information are uploaded in OCBIS portal (http://bhukosh.gsi.gov.in/Bhukosh/Public) for public viewing and downloading. This database has also been shared with National Disaster Management Authority (NDMA) and  other  stakeholders  including  Himachal  Pradesh  State  Disaster  Management Authority (HPSDMA) (in GIS format) for use in regional developmental planning of hill areas and further research studies for use in the management of landslide disasters in the country.

Monitoring of snow accumulation and avalanche early warning is carried out by the Defence Geoinformatics Research Establishment (DGRE),  erstwhile  Snow  and Avalanche  Study  Establishment  (SASE),  Chandigarh,  of  the  Defence  Research  & Development Organization (DRDO) for the vulnerable upper reaches of Himalayas in the states of Jammu & Kashmir and Himachal Pradesh. Regular operational avalanche warnings  are  issued  to  the  Army  and  civilian  population  in  hitherto  snow  bound regions of north-west Himalayas.

DGRE  is  also  the  nodal  agency  for  studying  and  developing  avalanche  mitigation technologies. The methodologies include aerial reconnaissance/ground surveys, which are further used as an input to prepare avalanche hazard maps.

- (c) & (d)  Yes Sir. In Himachal Pradesh, Landslide susceptibility assessment in 1: 50,000 scale, to  be  used  in  regional  planning  was  initiated  during  2014-15  under  the  National Landslide  Susceptibility  Mapping  Programme  for  approximately  42093  sq.km  area from  2014  to  2020.  The  susceptibility  map  provides  the  susceptibility  condition prevailing in the hilly areas of the state defining the slopes into three categories based on  the  relative  proneness  (high,  moderate  and  low)  of  the  slopes  to  landsliding modelled based on the relationships of various geofactors responsible for landslide in the  area  in  the  past.  During  the  study  period around  17102  landslides  have  been mapped in the whole state along with 6289 landslides with detail 42-point parameter.

For local landslide management, mesoscale (1: 10,000) scale susceptibility mapping of prioritized sectors has been initiated as per the SOP developed by GSI. Since 2020-21, GSI initiated the mesoscale (1: 10,000 scale) landslide susceptibility mapping in the identified prioritised sectors derived from the high and moderate susceptible areas in 1:  50,000  scale  for  further  subdividing  areas  into  domain-based  susceptibility  with high  density  data  input  and  providing  landslide  management  map  for  use  in  local landuse planning and mitigation planning. Since 2020-21 GSI has covered 19 sectors identified by NDMA and HPSDMA.

For providing suitable remedial measure for landslides, unstable slopes  etc.  detailed site-specific  landslide  investigations  on large  scale  e.g.  1:1000  are  being  taken  up regularly  as  per  the  requests  of  the  concerned  stakeholders.  GSI  has  completed detailed  site-specific  studies  of  12  landslide  sites  in  Kinnaur  district  prioritised  and requested by HPSDMA and one site in Chamba district.

Currently, work in 06 prioritised sectors on 1: 10,000 scale and one earthquake induce landslide  project  and  post  disaster  landslide  studies  (PDLS)  in  parts  of  Himachal Pradesh is under progress. As per the request of HPSDMA preliminary studies in the four  sectors  1)  Shimla  town  2)  Kalka-Shimla  Section  along  the  National  Highway (NH),  3) Jeori-Samdo Section along the National Highway.  4) Mandi-Kullu Section along the National Highway is also being initiated.

Besides, GSI has also extended the R & D project on experimental regional Landslide Early  Warning  System  (LEWS)  based  on  rainfall  thresholds  and  initiated  work  in Kinnaur and Shimla districts of Himachal Pradesh.

As  of  today,  no  warning  system  exists  for  occurrence  of  landslides.  However, landslide prone vulnerable zones are mapped  so as to alert respective local governments to put such areas under watch in association with heavy rainfall warnings as  and  when  issued  for  such  zones.  The precautionary  measures  include  the  passive control of avalanches viz. to ensure safe mobility, training to the troops (approximately  5000  in  number  every  year)  and  active  control  of  avalanches  by building control structures as a permanent solution.

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