Final answer:
The statement that a tsunami's first wave is always the largest is false. Tsunamis can arrive as a series of waves where later waves might be larger. These waves are caused by geological events like earthquakes and their impact varies based on ocean depth and coastal water depth.
Step-by-step explanation:
The statement that a tsunami rarely arrives as a single surge and typically has multiple surges is true; however, the idea that the first wave is always the largest is false. Instead, the first wave may not be the largest, and often it's one of the subsequent waves that can be the most massive and destructive. This unpredictability is part of what makes tsunamis so dangerous. The series of waves that constitute a tsunami are typically caused by significant disturbances such as underwater earthquakes, landslides, or volcanic eruptions.
A tsunami behaves differently in deep water compared to shallow water. In deep water, the waves may be relatively low in height and can travel at high speeds. As the tsunami approaches shallower coastal waters, its speed decreases and its height can increase dramatically, with the potential to rise up to 30 meters.
The 2004 Indian Ocean tsunami was a tragic example of the destructive power of tsunamis, caused by an earthquake with the energy equivalence of tens of thousands of atomic bombs. It resulted in an immense loss of life and highlighted the far-reaching impacts of these devastating natural events.