The epicenter was located near the eastern boundary of Sri Lanka.
Explanation
The 2004 Indian Ocean Tsunami was triggered by a massive undersea megathrust earthquake known as the Sumatra–Andaman earthquake. This event serves as a primary case study for understanding the generation, propagation, and impact of seismic sea waves (tsunamis).
Option Analysis
- The earthquake magnitude was 9.0 on the Richter scale. is Correct: The earthquake registered a magnitude of 9.1–9.3 on the Richter scale. It is recognized as the third-largest earthquake ever recorded.
- The waves penetrated up to 3 km inland. is Correct: Upon reaching the coast, the tsunami waves slowed down but increased in height (shoaling effect), possessing enough energy to penetrate up to 3 km inland in flat coastal regions.
- The wave speed was comparable to a commercial aircraft. is Correct: In the deep ocean, tsunami speed is a function of water depth ($v = \sqrt{g \cdot d}$). These waves travel at speeds of approximately 800 km/h, which is comparable to the speed of a commercial jet aircraft.
- The epicenter was located near the eastern boundary of Sri Lanka. is Incorrect: The epicenter of the earthquake was located off the west coast of northern Sumatra, Indonesia. Sri Lanka is located to the west of the epicenter and was severely impacted by the waves, but it was not the location of the seismic origin.
Key Takeaway
Tsunami Origin and Speed: Tsunamis originate from the displacement of the ocean floor (epicenter). In the 2004 event, the epicenter was near Sumatra. A defining characteristic of tsunamis is their jet-like speed in deep water, which diminishes as wave height increases in shallow water.