The correct option is (c).
Explanation
Tsunamis are large, high-energy ocean waves caused by the sudden vertical displacement of the water column. This displacement is typically triggered by undersea earthquakes, volcanic eruptions, or landslides. The 2004 Indian Ocean Tsunami was a result of a massive undersea megathrust earthquake.
Statement-wise Analysis
- Statement 1 is Correct: The 2004 tsunami was triggered by a massive earthquake resulting from the subduction of the Indian Plate beneath the Burma Plate (part of the Eurasian Plate). This tectonic movement caused a sudden vertical rise of the ocean floor by several meters, displacing a huge volume of water and generating the tsunami waves.
- Statement 2 is Incorrect: A characteristic phenomenon of a tsunami is that the water near the coast often recedes rapidly before the first giant wave hits. This occurs because the trough (the lowest part of the wave) reaches the shore before the crest (the highest part). The withdrawal serves as a natural warning sign of an approaching tsunami.
- Statement 3 is Correct: The epicenter of the earthquake was located off the western coast of northern Sumatra, Indonesia. This region lies along the Sunda Trench, a major subduction zone where the Indian Plate meets the Burma Plate.
Key Takeaway
Tsunamis are generated by the vertical displacement of the ocean floor, primarily due to subduction zone earthquakes. A distinct precursor to the arrival of the destructive wave crest is the rapid withdrawal of water from the coastline.