Lok Sabha Question No. 343 (STARRED), answered on 2021-03-19
Subject: Landslide Susceptibility Mapping
Ministry: EARTH SCIENCES
Asked by: P.R. Natarajan

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOK SABHA

## STARRED QUESTION NO.  *343 TO BE ANSWERED ON FRIDAY, MARCH 19, 2021

## LANDSLIDE SUSCEPTIBILITY MAPPING

## *343:  SHRI P.R. NATARAJAN

## Will the Minister of EARTH SCIENCES be pleased to state:

- (a) Whether  the  Government  is  having  any  data  on  the  number  of  incidents  of landslips/landslides occurred during the last three years;
- (b)
- if so, the details thereof, State/UT-wise;
- (c) whether the State Governments/UTs maintaining/having National Landslide Susceptibility Mapping (NLSM) in the respective State/UT and maintaining
- (d)
- if so, details thereof?

## ANSWER MINISTER FOR MINISTRY OF SCIENCE AND TECHNOLOGY AND MINISTRY OF EARTH SCIENCES (DR. HARSH VARDHAN)

(a) to (d): A statement is laid on the Table of the House.

## STATEMENT LAID ON THE TABLE OF THE LOK SABHA IN REPLY TO PARTS (a)  to  (d)  TO  THE  STARRED  QUESTION  NO.  *343(3 RD   Position)  REGARDING LANDSLIDE  SUSCEPTIBILITY  MAPPING  TO  BE  ANSWERED  ON  FRIDAY, MARCH 19, 2021 .

- (a) Yes  Sir.  Geological  Survey  of  India  (GSI)  has  collected  data  of  3656  nos.  of  major landslides that occurred during the last five years in different States/ UT, which have impacted lives and/ or infrastructure. These landslide data were collected by GSI through onsite field investigations under the Post-Disaster Studies programme taken up annually by GSI in all the landslide prone States/ UT as per GSI's Standard Operating Procedure, mainly in response to the requests received from the concerned State Governments.
- (b) The state-wise details of 3656 major landslide incidences, collected so far have been tabulated  below.  For  all  these  landslides,  during  field  validation,  GSI  collected  vital preliminary geoparametric attributes for each of the landslides, including studying its impacts,  future  vulnerability,  and  indicating  the  requirements  for  future  detailed geoscientific investigations, if any. All the above data are also used for updating GSI's existing national landslide inventory.

| Landslides occurred and studied during the period 2014-2020   | Landslides occurred and studied during the period 2014-2020   |
|---------------------------------------------------------------|---------------------------------------------------------------|
| State Name                                                    | Number of landslides                                          |
| Arunachal Pradesh                                             | 33                                                            |
| Assam                                                         | 120                                                           |
| Meghalaya                                                     | 32                                                            |
| Mizoram                                                       | 14                                                            |
| Tripura                                                       | 10                                                            |
| Manipur                                                       | 20                                                            |
| Nagaland                                                      | 34                                                            |
| Sikkim                                                        | 20                                                            |
| Himachal Pradesh                                              | 97                                                            |
| Jammu &Kashmir (UT)                                           | 169                                                           |
| Uttarakhand                                                   | 27                                                            |
| Karnataka                                                     | 194                                                           |
| Tamil Nadu                                                    | 196                                                           |

| Kerala      |   2238 |
|-------------|--------|
| Maharashtra |     78 |
| West Bengal |    374 |
| Total       |   3656 |

(c) - (d) The National Landslide Susceptibility Mapping (NLSM) project was launched by GSI  after  the  2013  Uttarakhand  disaster  as  per  the  directive  of  the  Technical  Advisory committee  (TAC).  With  the  NLSM  mapping,  GSI  has  prepared  1:  50,000  scale  landslide susceptibility map of 85% of the total target area (3.63 lakh sq. km. out of 4.2 lakh sq. km.) in different landslide prone States/ UTs. The work for the remaining area in Arunachal Pradesh is under execution and will be completed by Field Station (FS) 2021-22. During NLSM, GSI also collected historical information on 61287 nos. of landslides polygons using both Remote Sensing (RS) and field-based source data, out of which, 28831 landslides have already been field  validated  by  GSI  (Annexure-I).  This  huge  historical  national  landslide  inventory  is continuously being updated with the new landslide data collected year-wise as part of Postdisaster  studies.  Landslide  Susceptibility  Mapping  is  a  specific  multi-thematic  geoscientific mapping exercise, carried out primarily by the specialised technical resources of Geological Survey of India. In this geoscientific endeavour, the State Government has no specific role in mapping, other than reporting information of any new landslide incidence impacting lives and infrastructure, if any to GSI. While preparing the landslide susceptibility maps and updating the national landslide inventory, GSI  duly considers those landslide occurrences too that are reported by any State Government.

The Geographic Information System (GIS) enabled NLSM  outputs -the landslide susceptibility  and  national  landslide  inventory  map  are  already  shared  through  Web  Map Service (WMS) with NDMA, with a request to share such vital geo-data with all the landslide prone States/ UTs and other relevant stakeholders, for integrating the same in their respective landslide disaster management plans, and also for using in land-use zoning regulations in their respective landslide prone terrains. The above geo-data is also uploaded in GSI's Bhukosh map portal  (https://bhukosh.gsi.gov.in/Bhukosh/MapViewer.aspx)  as  'NLSM'  and  'Landslide Inventory' map services for free downloading by any stakeholder. Till date, 753 registered non-GSI users from 412 different affiliations have so far downloaded the above vital landslide geodata by raising 7118 different online requests to GSI in Bhukosh. In addition, the NLSM outputs also delineates the critical and problematic areas, where further up-scaled and detailed geoscientific  studies  are  required  for  undertaking  site  specific  effective  remediation  and mitigation by the concerned State Governments and other relevant stakeholders (e.g., road/ rail construction and maintenance authorities).

ANNEXURE-I

| Status National Landslide Susceptibility Mapping (NLSM) Programme 2014-2020   | Status National Landslide Susceptibility Mapping (NLSM) Programme 2014-2020   | Status National Landslide Susceptibility Mapping (NLSM) Programme 2014-2020   | Status National Landslide Susceptibility Mapping (NLSM) Programme 2014-2020   | Status National Landslide Susceptibility Mapping (NLSM) Programme 2014-2020   |
|-------------------------------------------------------------------------------|-------------------------------------------------------------------------------|-------------------------------------------------------------------------------|-------------------------------------------------------------------------------|-------------------------------------------------------------------------------|
| State/ UT                                                                     | Target area proposed (km 2 )                                                  | Target area completed so far (km 2 )                                          | Landslide polygons mapped (Nos.)                                              | Landslides field validated (Nos.)                                             |
| Assam                                                                         | 24100                                                                         | 24144                                                                         | 527                                                                           | 598                                                                           |
| Meghalaya                                                                     | 22020                                                                         | 22601                                                                         | 1525                                                                          | 791                                                                           |
| Mizoram                                                                       | 21040                                                                         | 21864                                                                         | 4221                                                                          | 2003                                                                          |
| Tripura                                                                       | 1300                                                                          | 1367                                                                          | 57                                                                            | 56                                                                            |
| Manipur                                                                       | 22500                                                                         | 23250                                                                         | 2405                                                                          | 1548                                                                          |
| Nagaland                                                                      | 16320                                                                         | 17294                                                                         | 2742                                                                          | 1554                                                                          |
| Sikkim                                                                        | 4980                                                                          | 4979                                                                          | 3379                                                                          | 651                                                                           |
| Himachal Pradesh                                                              | 42100                                                                         | 42108                                                                         | 17127                                                                         | 6420                                                                          |
| Jammu &Kashmir (UT)                                                           | 28700                                                                         | 28890                                                                         | 7465                                                                          | 2174                                                                          |
| Ladakh (UT)                                                                   | 40000                                                                         | 40065                                                                         | 838                                                                           | 166                                                                           |
| Uttarakhand                                                                   | 39000                                                                         | 39009                                                                         | 14782                                                                         | 4927                                                                          |
| Karnataka                                                                     | 30620                                                                         | 31323                                                                         | 1248                                                                          | 1278                                                                          |
| Goa                                                                           | 3540                                                                          | 3546                                                                          | 76                                                                            | 76                                                                            |
| Tamil Nadu                                                                    | 10080                                                                         | 10549                                                                         | 782                                                                           | 863                                                                           |
| Kerala                                                                        | 19330                                                                         | 19301                                                                         | 1396                                                                          | 3016                                                                          |
| Andhra Pradesh                                                                | 1150                                                                          | 1124                                                                          | 29                                                                            | 29                                                                            |
| Maharashtra                                                                   | 28190                                                                         | 29191                                                                         | 1134                                                                          | 1152                                                                          |
| West Bengal                                                                   | 2970                                                                          | 2980                                                                          | 1554                                                                          | 1529                                                                          |
| Arunachal Pradesh                                                             | 71210                                                                         | Work initiated in FS 2020-21 and scheduled to be completed by FS 2021-22.     | Work initiated in FS 2020-21 and scheduled to be completed by FS 2021-22.     | Work initiated in FS 2020-21 and scheduled to be completed by FS 2021-22.     |
| Total                                                                         | 429150                                                                        | 363585                                                                        | 61287                                                                         | 28831                                                                         |

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