Science Active deformation around South Lhonak lake in Sikkim, India Bella Brown October 12, 2023 Dave Petley, a renowned expert in landslide research and management, authors The Landslide Blog. The group of scientists studying landslides has been actively researching the Glacial Lake Outburst Flood (GLOF) that occurred in Sikkim on October 4, 2023. It is believed that the collapse of the moraine dam was caused by instability in the banks of South Lhonak lake, resulting in a displacement wave that breached the dam and caused significant damage. Bretwood Higman, a devoted reader, has utilized high-resolution satellite images of the area to greatly aid in understanding the events of October 4th. Hig has created an animation showing the changes in the moraine north of South Lhonak lake leading up to the events. https://storage.googleapis.com/planet-t2/south-lhonak-lake-6h63HVMSR/movie.mp4 The section of focus is located in the upper left corner of the picture, near the Planet symbol. The visible extent of movement is clearly visible. I have marked this on the Planet Labs image shown below, taken on September 26, 2023. The photo above shows the region above South Lhonak lake in Sikkim, India before the landslide and GLOF (glacial lake outburst flood). It is an image captured by a Planet Labs satellite on September 27th, 2023, and is being used with their permission. On October 9th, 2023, the image displayed depicts the amount of material that has been eroded due to landslides in this particular region. The picture above South Lhonak lake in Sikkim, India, shows the deformed area caused by a landslide and GLOF. It was taken by a Planet Labs satellite on 9 October 2023 and is protected by copyright. It is used with permission from Planet Labs. Dan Shugar, a highly impressive individual, has thoroughly examined this region and shared a thought-provoking thread on Twitter. Newly discovered landslide activity has been observed at South Lhonak Lake in Sikkim. This small shift has resulted in flooding and indicates that recently uncovered sediments are not stable and may experience further failure in the next few weeks until reaching a new balance on the slope. @planet #GLOF #teesta “Please return any notifications and comments in English.” Dan has a Twitter thread discussing the path of devastation caused by the flood and how it led to additional landslides downstream because the river banks were undercut. On this day, @planet obtained a SuperDove satellite image of #SouthLhonakLake with minimal cloud cover. This image reveals the damage caused by the Glacial Lake Outburst Flood (#GLOF) at the #Chungthang dam (#Teesta3HEP). 1/n pic.twitter.com/BpgAHyh33n — Dan Shugar (@WaterSHEDLab) October 10, 2023 Reading all the posts in the thread is beneficial. Reference Planet Lab PB 2023 is a program that aims to improve life on Earth through space technology. It is based in San Francisco, CA and can be accessed through the Planet Application Program Interface at https://www.planet.com/. Go back to the homepage of The Landslide Blog. Text © 2023. The authors. CC BY-NC-ND 3.0 Unless stated otherwise, all images are protected by copyright. You are not allowed to use them without the explicit consent of the copyright owner.