They cause large waves in the open ocean but small ones near the shore is that true or false about a tsunamis
True. Tsunamis can cause large waves in the open ocean, often reaching heights of several meters or more. However, as the waves approach the shore and the water becomes shallower, the energy of the tsunami is usually dispersed, resulting in smaller waves near the shore.
That statement is generally true. Tsunamis, also known as seismic sea waves, can produce enormous waves in the open ocean due to their long wavelengths and large amount of energy. These waves can travel across vast distances without losing much energy. However, as a tsunami approaches shallow water near the shore, the wave's energy becomes compressed, causing the wave height to increase while the wavelength decreases. As a result, tsunamis often appear as small, rapidly advancing walls of water near the shore. These waves can still be extremely dangerous despite their smaller size, as they carry a tremendous amount of force and can cause significant flooding and destruction.
Ocean surface waves are not just on the surface but the water under them follows vertical circular paths of diminishing radius beneath the waves. About a half wavelength down the circles become small. If the water depth gets down to around half a wavelength the wave slows down. Then as the water becomes shallower the frequency of wave crests does not change but it slows down. The water at the top therefore has to rise to fit the water in a shorter wave. It is this effect that makes for good surfing but dangerous beaches..
Yes, that statement is true. When ocean surface waves propagate, the water particles underneath the wave follow circular paths called orbital motions. These circular paths diminish in radius as we move deeper into the water column. A half wavelength below the surface, the circular paths become smaller.
As the water depth decreases to around half a wavelength, the wave's speed decreases. This change in speed occurs because the wave encounters more resistance from the seafloor. However, the frequency of wave crests remains unchanged.
As the wave enters shallower water, the wave's speed further decreases. The water at the top of the wave needs to rise in order to adjust to the shorter wavelength, resulting in the top of the wave becoming steeper. This effect is what makes certain areas ideal for surfing but can also make beaches dangerous due to the sudden and powerful breaking waves.