What makes tidal waves

It does seem a little weird. It's all because the tidal force is a differential force—meaning that it comes from differences in gravity over Earth's surface. Here's how it works:.

On the side of Earth that is directly facing the moon, the moon's gravitational pull is the strongest. The water on that side is pulled strongly in the direction of the moon. On the side of Earth farthest from the moon, the moon's gravitational pull is at its weakest. At the center of Earth is approximately the average of the moon's gravitational pull on the whole planet.

Arrows represent the force of the moon's gravitational pull on Earth. To get the tidal force—the force that causes the tides—we subtract this average gravitational pull on Earth from the gravitational pull at each location on Earth. The result of the tidal force is a stretching and squashing of Earth. This is what causes the two tidal bulges. Arrows represent the tidal force. It's what's left over after removing the moon's average gravitational pull on the whole planet from the moon's specific gravitational pull at each location on Earth.

These two bulges explain why in one day there are two high tides and two low tides, as the Earth's surface rotates through each of the bulges once a day. The Sun causes tides just like the moon does, although they are somewhat smaller.

When the wave hit shore, it was said to destroy everything. There are also other, usually less destructive tsunami waves caused by weather systems called meteotsunamis. These tsunami waves have similar characteristics to the classical earthquake driven tsunamis described above, however they are typically much smaller and focused along smaller regions of the oceans or even Great Lakes. Meteotsunamis are often caused by fast moving storm systems and have been measured in several cases at over 6 feet 2 meters high.

A study found that smaller meteotsunami waves strike the east coast of the U. Tides are actually waves, the biggest waves on the planet, and they cause the sea to rise and fall along the shore around the world.

Tides exist thanks to the gravitational pull of the Moon and the Sun, but vary depending on where the Moon and Sun are in relation to the ocean as Earth rotates on its axis. The Moon, being so much closer to Earth, has more power to pull the tides than the Sun and therefore is the primary force creating the tides. Centrifugal force is the same force that smooshes riders to the outside walls of spinning carnival rides.

Meanwhile, Earth continues to spin. A specific point on the planet will pass through both of the bulges and both of the valleys. When a specific place is in the location of a bulge it experiences a high tide. When a specific place is in the location of a valley it experiences a low tide. During one planetary rotation or one day a specific location will pass through both bulges and both valleys, and this is why we have two high tides and two low tides in a day.

But, while Earth takes 24 hours to complete one rotation, it must then rotate an additional and 50 minutes to catch up with the orbiting Moon.

This is why the time of high tide and the time of low tide change slightly every day. The Sun also has a part to play in causing the tides, and its location in relation to the Moon alters the strength of the pull on the ocean. This happens when the Moon is either on the same side of Earth as the Sun or directly on the opposite side of Earth.

Smaller-than-usual tidal ranges, called neap tides, occur when the gravitational force of the Sun is at a right angle to the pull from the Moon. The two forces of the Sun and Moon cancel each other out and create a neap tide. But continents obstruct the flow of water, causing this seemingly simple daily cycle to be a bit more complicated. Because of continental obstruction, some locations experience two tides a day that are more or less the same height known as semidiurnal tides , some locations experience one tide at one height and the second at a different height mixed semidiurnal tides , and some locations have so much interference from land that they only experience one high tide and one low tide per day diurnal tides.

The local geography can also affect the way the tides behave in a location. Shores around coastal islands and inlets may experience delayed tides compared to smoother surrounding coasts since the water must funnel in through constrained waterways. The intertidal zone , the coastal area tides submerge for part of the day, is home to many ocean creatures. It takes a special set of adaptations to live a life half the time scorched by the Sun and the other submerged underwater.

Moreover, the incoming tide promises a constant pounding by ocean waves. Shelled mollusks like periwinkles, muscles, and barnacles cling to rocks, sea stars wedge themselves in crevices, and crabs hide in fronds of algae.

A red tide is not a true tide at all but rather a term used to describe the red color of an algal bloom. Algae are integral to ocean systems, but when they are supplied with excessive amounts of nutrients they can explode in number and smother other organisms. The algae may produce toxins or they can die, decay, and the bacteria decomposing them take up all the oxygen. This massive growth of algae can become harmful to both the environment and humans, which is why scientists often refer to them as harmful algal blooms or HABs.

Tidal movements are tracked using networks of nearshore water level gauges, and many countries provide real-time information with tidal listings and tidal charts. Tides can be tracked at specific locations in order to predict the height of a tide, i. The tides there range from 11 feet 3. This erosion also releases nutrients into the water that help support marine life. The currents associated with the tides are called flood currents incoming tide and ebb currents outgoing tide.

Having reliable knowledge about the tides and tidal currents is important for navigating ships safely, and for engineering projects such as tidal and wave energy , as well as for planning trips to the seashore.

Skip to main content. Credit: Pixabay. Are You An Educator? At Smithsonian Ocean, we have lesson plans, activities, and resources to help you engage your students in the wonders of our oceans. This is a map ocean surface currents from John James Wild, The major wind patterns drive oceanic currents.

Ekman transport creates a spiral as wind drags the surface of the ocean, which then drag deeper layers of water. Differences in temperature and salinity drive deep ocean currents.

Locals in Zebbug, Malta created salt pans where they can collect sea salt after the super salty Mediterranean Sea water has dried. Christine M. A rip current can be seen from up above. Currents on the ocean surface are driven by wind, temperature, gravity, and the spin of Earth on its axis. Waves play an important role in the way coastal ecosystems function, and also provide tourism dollars because of their draw for surfers. Measure content performance. Develop and improve products.

List of Partners vendors. Share Flipboard Email. Laura Klappenbach. Ecology Expert. Laura Klappenbach, M. Updated October 15, Featured Video. Cite this Article Format. Klappenbach, Laura. How Do Tides and Waves Work? Ocean Waves: Energy, Movement, and the Coast. About the Architecture of Tsunami-Resistant Buildings. Winds and the Pressure Gradient Force.

A sudden vertical movement of the ocean floor displaces a huge amount of water. One cubic metre of water weighs one tonne, so a square column of water one metre across and metres 3 km deep weighs tonnes! Earthquakes happen on a much larger scale than one square metre and when you add up the weight of all that water suddenly moving up or down, you've got an incredible amount of energy spreading out as a wave across the ocean.

In deep water, these waves may be only a metre or two high but travel at speeds of up to km per hour. Now if you've got enough energy to lift tonnes of water by one metre, you'd be able to lift tonnes of water much higher right?

Well that's roughly what happens when tsunamis reach shallow water.