Damage From the Air

Advances in satellite technology have greatly improved the usefulness of satellites in assessing the impact of natural disasters.

• Click here to see a satellite-derived damage assessment map for the Kathmandu Valley.

This map is color coded and provides a view of how the ground surface has changed as a result of the earthquake. Locations in yellow experienced some ground surface change, while areas in red experienced significant ground surface change.

• Click here to see a satellite view of the entire 40 x 40 km (25 x 31 mile) region around Kathmandu showing ground surface change.

1. Would you expect there to be lots of building damage in the Kathmandu Valley? Explain.
Yes, the damage assessment map would indicate that there was probably lots of damage to buildings in the Kathmandu Valley. Many areas in the Kathmandu Valley are colored in red indicating significant ground surface change as a result of the earthquake. These areas likely suffered significant building damages because of extensive ground movement.

• Click here to see a map indicating damage done to buildings as a result of the earthquake.

Red dots indicate buildings/structures that have undergone major damage. Purple dots indicate buildings/structures that have been totally destroyed.

2. Does this new data on the map support your answer to question 1? Explain.
Yes, this building damage data supports my answer to question 1. The Kathmandu Valley has many red and purple dots indicating major or complete destruction of many buildings.

Although a great deal of destruction to buildings was caused by significant movement of the Earth’s surface during the earthquake, a large amount of damage also resulted from shoddy and faulty construction of buildings.

The Gorkha Earthquake was also responsible for a large number of landslides/avalanches. Satellite imagery has helped identify over 3,000 landslides/avalanches that occurred as a result of the earthquake and its aftershocks. The Langtang Valley, an area popular with trekkers, was particularly hard hit by avalanches.

• Click here to see the Langtang Valley on April 27, 2015, before the earthquake.
• Click here to see the Langtang Valley on April 30, 2015, after the earthquake.
• Click here to see an enhanced color version that emphasizes the avalanche areas.

The avalanches (in turquoise) are clearly visible in the enhanced color map.

3. What do you notice about the five villages that have been labelled on the map?
The five villages on the map are either right in or adjacent to avalanche areas.


4. Which village was completely covered by the avalanche?
Langtang village was completely covered by the avalanche.

Contrasting views of Langtang village before and after the avalanche.

All five villages, Chymaki, Gumba, Langtang, Mundu and Sindum were affected by avalanches caused by the Gorkha earthquake. Langtang village was completely buried by a large avalanche that originated in the glacier above the village. Approximately 400 permanent residents and 100 trekkers are believed to have been killed by this avalanche which completely destroyed the village.