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Emergency Analysis of Landslide in Nepal

In August 2026, Rikkyo University's Faculty of Earth and Environmental Sciences launched an urgent analysis of a substantial landslide that occurred near the Nepal-China border. Led by Associate Professor Hiroto Nagai, an expert in glaciology and geographic information science, the analysis utilized satellite imagery from the Landsat-9 Earth observation satellite, captured on August 26, 2026.

Key Findings of the Urgent Satellite Analysis

The initial findings indicate that the landslide was not a conventional landslide typical of mountainous regions, which often leads to the formation of sediment dams, but rather likely originated from a significant collapse at the terminal end of a glacier.

Analysis of Satellite Imagery

Images taken at 4:47 AM UTC revealed a dramatic loss of mass at the glacier’s terminal, with a flow path spanning approximately 1 kilometer in width. The extent of the affected area is estimated at about 1.9 square kilometers, showcasing major topographical shifts from elevations of around 5,180 meters to about 3,970 meters—a vertical drop of approximately 1,200 meters over a horizontal distance of about 1,800 meters.

Nature of the Collapse

Unlike traditional glacier lake outburst floods (GLOF), no large glacier lake was identified in the vicinity. Therefore, it is reasoned that the phenomenon was a large-scale collapse involving a mix of rock debris and glacier ice. This instability at the glacier’s steep slope led to significant disintegration, incorporating surrounding rock and debris, resulting in rapid water flow through steep valleys.

Expert Comments and Significance

In light of this disaster, Professor Nagai expressed his condolences for those affected, stating that remote sensing technology is pivotal in capturing the scale and origin of events in areas where ground access is challenging. Preliminary analysis underscores the importance of understanding the disaster's mechanisms, with an emphasis on evolving interpretations as more data becomes available.

Background on Professor Hiroto Nagai

Hiroto Nagai serves as Associate Professor in the Department of Geography at Rikkyo University, where he specializes in snow and ice science, geographic information science, and satellite remote sensing. He has previously utilized Earth observation satellite data to investigate global changes in the snow and ice environment, as well as to respond to various natural disaster emergencies.

The results presented here are based on satellite imagery from the day of the disaster and should be viewed as preliminary assessments pending further detailed observations.

For more insights from Professor Nagai, visit the following URL: Satellite Analysis of Landslide Disaster.