Earthquake Can Cause Tsunami, True or False?

Earthquakes are a frightening natural disaster, especially for those who live in coastal areas. How could it not be, an earthquake can cause tsunami. How can an earthquake cause a more devastating natural disaster?

At this time, we will discuss the relationship between earthquakes and tsunami disasters. Want to know the complete explanation? Let's look at the following information!

What Is Tsunami?

Before discussing whether or not earthquakes can cause tsunamis, we need to first understand what a tsunami is. Tsunamis are huge sea waves that are caused by earthquakes under the sea. This name comes from the Japanese words, tsu which means “harbor” and nami which means “wave”.

These waves move very fast, sometimes more than 900 km per hour. When a tsunami hits land, it will look like a huge wall of water and destroy everything in its path. The waves kept coming for hours, hitting the shore every few minutes and flooding large areas.

Is It True That Earthquake Can Cause Tsunami?

From the definition of tsunami explained above, we know that this natural disaster was caused by an earthquake. So, the statement that earthquake can cause tsunamis is true. However, how could this happen?

Tsunamis happen when underwater earthquakes cause the ocean floor to move up or down. This movement pushes water above it, creating massive waves that can travel for thousands of kilometers. These waves get bigger and more destructive as they reach shallow waters near the shore.

Most tsunamis around the world are caused by subduction zones earthquakes. Here, one tectonic plate dives under another, creating enough pressure to shift the seafloor. When this happens quickly, the water above moves with it, starting a tsunami.

The earthquake must be strong to occur a tsunami. Usually above magnitude 7.0 and close to the ocean surface. Shallow earthquakes transfer energy to the seafloor, while deeper ones do not disturb the water enough to cause waves.

When a tsunami forms, the first warning sign might be strong ground shaking or the ocean suddenly pulling back from the shore. This can happen minutes before the waves hit, giving people some time to evacuate to higher ground.

What Type of Earthquake Can Cause Tsunami?

Not every earthquake causes a tsunami. It depends on how the Earth’s crust moves and whether the seafloor is disturbed. Without this vertical movement, even strong quakes usually won’t trigger tsunamis. Here are several types of earthquakes that can cause tsunamis.

1. The Earthquake Needs to Happen Underwater

Tsunamis don’t happen unless the ocean gets disturbed. For this to occur, the earthquake must either happen under the sea or make materials fall into it. If the quake happens on land far from water, you’re safe from a tsunami.

2. It Has to Be a Powerful Quake

Not all earthquakes are strong enough to cause tsunamis. If the quake’s magnitude is less than 6.5, it won’t shake things up enough to move the ocean. Big quakes pack the punch needed to disturb the seafloor and start waves.

3. The Quake Must Be Close to the Surface

Depth matters when it comes to tsunamis. Shallow earthquakes, less than 70 kilometers deep, are more dangerous because they transfer their energy to the seafloor. Deep ones fizzle out before they can make waves.

4. The Seafloor Has to Move Up or Down

Imagine the ocean floor lifting or sinking suddenly—that’s what sets off a tsunami. This vertical motion pushes or pulls the water, starting the waves. Without this kind of movement, even big quakes can’t create tsunamis.

Other Causes of Tsunamis

While it is true that earthquakes can cause tsunamis, they are not the only cause. The reason is, tsunamis can occur due to various other reasons such as the following.

When a volcano erupts, the powerful vibrations can disturb the seafloor, pushing large amounts of water upward. This is what likely caused the tsunami in Banten, where the eruption of Mount Anak Krakatau triggered massive waves.

Underwater landslides are another cause of tsunamis. Imagine the seabed, with its hills and valleys, suddenly collapsing after an earthquake or volcanic blast. The water above rushes to fill the space, creating waves that can reach the coast as a tsunami.

Lastly, meteors striking the ocean could generate tsunamis, though this is rare. Imagine dropping a giant rock into a lake, it creates ripples. A meteor hitting the sea would do the same but on a much larger scale.

From the explanation above, the conclusion is earthquake can cause tsunami if it meets several specific criterias. The other important point is that tsunamis are not only caused by earthquakes.