The increase in height as a tsunami approaches shore is due to

A. The increase in frequency as the wave approaches shore.

B. The increase in speed as the wave approaches shore.

C. The decrease in speed as the wave approaches shore.

D. The constructive interference with the wave reflected from shore.

(c) The decrease in speed as the wave approaches the shore.

Explanation:

A tsunami is a series of successive ocean waves usually caused by landslide, earthquake or volcanic eruption. The speed of a tsunami decreases and its height increases as it moves from the deep part of a water body to the shallow part (e. g shore) of the water body. In other words, for a tsunami, the deeper the water, the slower its speed and consequently the higher it grows. Therefore it is safe to say that an increase in the height of a tsunami as it approaches a shore is due to the decrease in speed as the wave approaches the shore.

C. The decrease in speed as the wave approaches shore.

Explanation:

The waves break when approaching the shore because the depth decreases. Thus, the wave travels more slowly and increases its height. There comes a time when the part of the wave on the surface travels faster than the one that travels under water, the ridge destabilizes and falls against the ground.