Tsunami Behavior Explained

This question asks us to evaluate two statements about tsunamis. Let's break down each statement to determine its accuracy.

Statement 1: Deepwater Tsunami Height

Statement 1: In deepwater, tsunamis are rarely over 1m high.

This statement is true. When a tsunami travels through the deep ocean, its energy is spread across a vast volume of water. This results in:

• Long Wavelengths: Tsunamis have very long wavelengths, often exceeding 100 kilometers.
• Low Amplitude: Despite their immense energy, their height (amplitude) in deep water is typically very small, often less than a meter (about 3 feet). This makes them almost unnoticeable to ships at sea.
• High Speed: They travel very fast in deep water, comparable to the speed of a jetliner.

The dramatic increase in tsunami height occurs as the wave approaches shallower coastal waters, a process called the shoaling effect.

Statement 2: Tsunami Inundation Distance

Statement 2: A large tsunami can flood land up to more than 1.5 km from the coast.

This statement is also true. While tsunamis are small in the deep ocean, their impact near the coast can be devastating. Factors influencing inundation distance include:

• Coastal Topography: Flat, low-lying coastal areas are more susceptible to deep inland flooding.
• Tsunami Size: Larger and more powerful tsunamis carry more water and energy, allowing them to surge further inland.
• Event Evidence: Major historical tsunamis have demonstrated the capability to flood areas several kilometers inland. For instance, following the 2004 Indian Ocean tsunami, significant inundation occurred far from the shoreline in many affected regions.

Therefore, it is accurate to say that a large tsunami can flood areas exceeding 1.5 kilometers inland.

Conclusion on Statements

Since both Statement 1 (low height in deep water) and Statement 2 (significant inland flooding potential) are factually correct descriptions of tsunami behavior, the correct option is the one that affirms both statements.