Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya
The Himalayan state of Sikkim is prone to some of the world’s largest landslides, which have caused catastrophic damage to lives, properties, and infrastructures in the region. The settlements along the steep valley sides are particularly subject to frequent rainfall-triggered landslide events durin...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | GeoHazards |
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| Online Access: | https://www.mdpi.com/2624-795X/4/1/3 |
| _version_ | 1797611569409949696 |
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| author | Rajinder Bhasin Gökhan Aslan John Dehls |
| author_facet | Rajinder Bhasin Gökhan Aslan John Dehls |
| author_sort | Rajinder Bhasin |
| collection | DOAJ |
| description | The Himalayan state of Sikkim is prone to some of the world’s largest landslides, which have caused catastrophic damage to lives, properties, and infrastructures in the region. The settlements along the steep valley sides are particularly subject to frequent rainfall-triggered landslide events during the monsoon season. The region has also experienced smaller rock slope failures (RSF) after the 2011 Sikkim earthquake. The surface displacement field is a critical observable for determining landslide depth and constraining failure mechanisms to develop effective mitigation techniques that minimise landslide damage. In the present study, the persistent scatterers InSAR (PSI) method is employed to process the series of Sentinel 1-A/B synthetic aperture radar (SAR) images acquired between 2015 and 2021 along ascending and descending orbits for the selected areas in Gangtok, Sikkim, to detect potentially active, landslide-prone areas. InSAR-derived ground surface displacements and their spatio-temporal evolutions are combined with field investigations to better understand the state of activity and landslide risk assessment. Field investigations confirm the ongoing ground surface displacements revealed by the InSAR results. Some urban areas have been completely abandoned due to the structural damage to residential housing, schools, and office buildings caused by displacement. This paper relates the geotechnical investigations carried out on the ground to the data obtained through interferometric synthetic aperture radar (InSAR), focusing on the triggering mechanisms. A strong correlation between seasonal rainfall and landslide acceleration, as well as predisposing geological-structural setting, suggest a causative mechanism of the landslides. |
| first_indexed | 2024-03-11T06:29:34Z |
| format | Article |
| id | doaj.art-ec51a7383dbf46409b445ec2fc7a1418 |
| institution | Directory Open Access Journal |
| issn | 2624-795X |
| language | English |
| last_indexed | 2024-03-11T06:29:34Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | GeoHazards |
| spelling | doaj.art-ec51a7383dbf46409b445ec2fc7a14182023-11-17T11:19:25ZengMDPI AGGeoHazards2624-795X2023-01-0141253910.3390/geohazards4010003Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim HimalayaRajinder Bhasin0Gökhan Aslan1John Dehls2Norwegian Geotechnical Institute (NGI), 0484 Oslo, NorwayGeological Survey of Norway (NGU), 7491 Trondheim, NorwayGeological Survey of Norway (NGU), 7491 Trondheim, NorwayThe Himalayan state of Sikkim is prone to some of the world’s largest landslides, which have caused catastrophic damage to lives, properties, and infrastructures in the region. The settlements along the steep valley sides are particularly subject to frequent rainfall-triggered landslide events during the monsoon season. The region has also experienced smaller rock slope failures (RSF) after the 2011 Sikkim earthquake. The surface displacement field is a critical observable for determining landslide depth and constraining failure mechanisms to develop effective mitigation techniques that minimise landslide damage. In the present study, the persistent scatterers InSAR (PSI) method is employed to process the series of Sentinel 1-A/B synthetic aperture radar (SAR) images acquired between 2015 and 2021 along ascending and descending orbits for the selected areas in Gangtok, Sikkim, to detect potentially active, landslide-prone areas. InSAR-derived ground surface displacements and their spatio-temporal evolutions are combined with field investigations to better understand the state of activity and landslide risk assessment. Field investigations confirm the ongoing ground surface displacements revealed by the InSAR results. Some urban areas have been completely abandoned due to the structural damage to residential housing, schools, and office buildings caused by displacement. This paper relates the geotechnical investigations carried out on the ground to the data obtained through interferometric synthetic aperture radar (InSAR), focusing on the triggering mechanisms. A strong correlation between seasonal rainfall and landslide acceleration, as well as predisposing geological-structural setting, suggest a causative mechanism of the landslides.https://www.mdpi.com/2624-795X/4/1/3landslideInSARPSIIndiaSikkimGangtok |
| spellingShingle | Rajinder Bhasin Gökhan Aslan John Dehls Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya GeoHazards landslide InSAR PSI India Sikkim Gangtok |
| title | Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya |
| title_full | Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya |
| title_fullStr | Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya |
| title_full_unstemmed | Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya |
| title_short | Ground Investigations and Detection and Monitoring of Landslides Using SAR Interferometry in Gangtok, Sikkim Himalaya |
| title_sort | ground investigations and detection and monitoring of landslides using sar interferometry in gangtok sikkim himalaya |
| topic | landslide InSAR PSI India Sikkim Gangtok |
| url | https://www.mdpi.com/2624-795X/4/1/3 |
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