Previous answer: gravity
Gravity is part of the answer, but not all of it. That doesn't explain how the water rose to point where it could crash down by gravity. I'm a little rusty but if I remember my old college class correctly, as waves move towards shore, they disturb the water underneath them at a depth equal to one half their wavelength.
So as an example if 2 waves were coming in together with one trailing the other by 8 feet, they disturb the water underneath them at a depth of 4 feet. When they are in deep water, they don't crest but just look like 2 rolling hills. As they approach water shallower than one half their wavelength, the disturbed water below the wave is hitting against the ocean floor and begins to put a drag on the lower part of the wave. Meanwhile the top of the wave isn't disturbed so it crests and falls over the bottom part of the wave.
Mostly its wind.
tsunami
It can trigger a tsunami.
When waves grow so tall that they topple over, they form ocean breakers called "whitecaps." These whitecaps are created when wind causes the wave crest to become unstable and break, leading to the formation of foamy white waves.
Ocean breakers are large waves that form and break typically near the shoreline. They are caused by the interaction of wind, currents, and obstacles in the water. Breakers are important for coastal erosion and the formation of beaches.
What causes ocean floor features to form
they crash land and scan the bottom
Mostly its wind.
New material forms on the ocean floor of the mid-ocean ridge due to plate tectonics and volcanic activity. Volcanic eruptions deposit cooled magma on the ocean floor.
tsunami
Convection currents.
It can trigger a tsunami.
On march 24, 1989, the Exxon Valdez grounded on the ocean floor, leading to an oil spill
Waves crash on the shore when they approach shallow water, causing the wave height to increase and eventually break. This is due to the friction between the rising wave and the ocean floor, which slows down the bottom of the wave and causes the top to topple forward, forming a breaking wave.
Movement of the ocean, or tides are directly related to deep ocean currents. Deep ocean currents are also responsible for the wind that causes the waves to crash into the shore.
In the middle of the ocean is a rift where the ocean floor squeezes out lava and pushes the ocean plates apart.
Breakers form as waves interact with the ocean floor. Undertows are moving out to sea along the ocean floor. Therefore, undertows must contribute to the slowing down of incoming waves and the buildup of water molecules that cause the waves to increase in height.