The tsunami is also known as sea seismic wave, sometimes it is mistakenly called a tidal wave. It is caused by the movement of a large amount of water due to earthquake, volcanic eruption, some underwater nuclear explosions, landslides, meteor impacts. Under the influence of large waves created in these ways, large floods with catastrophic consequences occur. The tsunami does not melt glacier, nor do they depend on weathering.
The answer is: can cause extensive flooding.