The magnitude 5.2 seismic event recorded near the border between Nepal and China on 26 August 2026 at 8:37 AM local time (02:52:10 UTC) has now been determined to be a glacial collapse and debris flow that has caused catastrophic impacts downstream.
This seismic event was initially reported as a magnitude 4.4 earthquake. However, further analysis of long-period seismic waves and satellite imagery has revealed that no earthquake had occurred in the region. The seismic energy was actually generated by a glacial collapse and debris flow.
The outburst flood was triggered by an ice and rock avalanche from a glacier in the upper catchment that swept the Bhote Koshi–Trishuli river corridor across the Nepal–China border. The catastrophic flash flood and mudslides have caused immense damage to human lives and properties in the region. About 160 people are reported dead (provisional figure) and hundreds are missing.
In the recent past, a glacial lake outburst had caused flash floods and mudslides on the Thame River in Solukhumbu district in Nepal on 16 August 2024.
A very usual seismic event not caused by earthquake was reported on 16 September 2023 in Greenland when seismic stations across the globe recorded a uniform single frequency seismic waves lasting for nine days. The waves of this seismic event did not appear to have been generated by an earthquake or a volcano. A detailed analysis revealed that a massive rockslide triggered by climate change had created a mega-tsunami in the remote Dickson Fjord in east Greenland. The vibrations generated by back-and-forth sloshing of tsunami across the fjord were recorded globally as long-lasting monochromatic seismic waves.
Generally, naturally occurring seismic events are caused by earthquakes due to movements of tectonic plates, however seismic events are also occasionally caused by extreme natural events like glacial collapse and volcano and anthropogenic events like underground nuclear testing.
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References:
- United States Geological Survey. M 5.2 Landslide – 55 km NW of Kodāri̇̄, Nepal. Posted 26 August 2026. Available at https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb/executive
- Disaster Data Releases from Planet Labs PBC. Planet Crisis Response — Bhote Koshi–Trishuli Outburst Flood, Nepal (2026). Available at https://source.coop/planet/disasterdata/nepal-flash-flood-2026-08-26#planet-crisis-response-bhote-koshitrishuli-outburst-flood-nepal-2026
- NASA. Landslides, floods – Nepal Flooding August 2024. Posted 20 August 2024. Available at https://appliedsciences.nasa.gov/what-we-do/disasters/disasters-activations/nepal-flooding-august-2024
- Svennevig K., et al 2024. A rockslide-generated tsunami in a Greenland fjord rang Earth for 9 days. SCIENCE. 12 September 2024. Vol 385, Issue 6714 pp. 1196-1205. DOI: https://doi.org/10.1126/science.adm9247
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Related articles:
What caused the Mysterious Seismic Waves Recorded in September 2023 (16 September 2024)
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