Disasters and Disaster Management – Sendai Framework, Floods, Cyclones, etc.

Massive Greenland Landslide

Prelims Only | Enviro & Biodiversity | Mains Paper 3: Disaster Management
Note4Students

From UPSC perspective, the following things are important :

Prelims level: Greenland Landslide, Dickson Fjord

Why in the News?

  • In September 2023, seismic stations across the world detected an unusual signal which persisted for 9 days.
    • It was caused by a massive landslide in Greenland’s Dickson Fjord (i.e narrow sea inlet with steep sides or cliffs, created by a glacier).

About the Massive Greenland Landslide

  • The landslide involved a colossal volume of 25 million cubic metres of rock and ice, equivalent to filling 10,000 Olympic-sized swimming pools.
  • The landslide involved 25 million cubic meters of rock and ice, which is enough to fill 10,000 Olympic-sized swimming pools.
  • This event caused a mega-tsunami with waves as high as 200 meters, which significantly impacted the area.
  • The seismic waves created by the landslide lasted for 9 consecutive days.
  • The loss of such a large amount of glacier ice highlights how global warming is speeding up damage to these fragile environments.

Causes of the Greenland Landslide

  • The main reason for the landslide was global warming, which caused the glaciers in Greenland to melt and shrink over recent decades.
    • The Hvide Stovhorn peak glacier had been holding up the mountain slopes, but as it thinned, the rock above it became unstable and eventually collapsed.
  • The permafrost (frozen ground) on the mountain’s steep slopes started melting because of rising temperatures, making the slopes unstable.
  • When the rocks and ice fell into the fjord, it triggered a submarine landslide (a landslide under water), which made the event even bigger and caused a mega-tsunami.

Back2Basics: Seismic Waves

Type  Sub-Type Wave Characteristics Speed Medium of Travel Movement Impact
Body Waves P-Waves (Primary Waves) • Longitudinal/compressional waves.
• Fastest seismic waves.		 Fastest (First to arrive) Solids and liquids Particles move back and forth in the direction of wave travel. First waves to be detected during an earthquake, cause less damage.
S-Waves (Secondary Waves) • Transverse/shear waves.
• Slower than P-waves.		 Slower than P-Waves Solids only Particles move perpendicular to the wave’s direction. Follow P-waves, more ground shaking, cause more damage than P-waves.
Surface Waves Love Waves • Transverse horizontal motion.
• Faster than Rayleigh waves.		 Slower than S-Waves Earth’s surface Particles move side to side, horizontally. Cause significant structural damage.
Rayleigh Waves • Rolling motion.
• Slowest seismic waves.		 Slowest of all seismic waves Earth’s surface Particles move in an elliptical motion (both vertical and horizontal). Cause vertical and horizontal ground movement, highly destructive.

 

PYQ:

[2021] Describe the various causes and the effects of landslides. Mention the important components of the National Landslide Risk Management Strategy.

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