Why in the News
New imagery from the NISAR satellite has shown that Mexico City is sinking at an alarming rate of nearly 25 cm per year, mainly due to excessive groundwater extraction.
What is Land Subsidence
- Gradual sinking or settling of the Earth’s surface
- Commonly caused by:
- Excessive groundwater withdrawal
- Mining
- Natural geological processes
Why is Mexico City Sinking
- Built on an ancient lake bed
- Heavy extraction of groundwater from aquifers
- Rapid urbanisation and infrastructure load
- Shrinking aquifers causing ground compaction
About NISAR Satellite
- NASA and Indian Space Research Organisation (ISRO) joint mission
- Full Form: NASA ISRO Synthetic Aperture Radar
Features of NISAR
- Uses Synthetic Aperture Radar (SAR)
- Can detect surface changes in real time
- Works in:
- Day and night
- All weather conditions
| [2019] For the measurement/ estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the vegetation of a specific location 2. Greenhouse gas emissions from rice paddies of a specific location 3. Land surface temperatures of a specific location Select the correct answer using the code given below. [A] 1 only [B] 2 and 3 only [C] 3 only [D] 1, 2 and 3 |
