Will The Earthquake Cause a Tsunami? Check Out The Explanation!

If you noticed, every time there is an earthquake update, it often contains information about whether the earthquake has the potential to cause a tsunami or not. Have you ever questioned, will the earthquake cause a tsunami?

To find the answer to this question, let's look at the complete explanation below!

Will The Earthquake Cause a Tsunami?

Did you know that earthquakes can create tsunamis? It happens when the ocean floor suddenly moves, then pushing huge amounts of water and creating huge waves. This is most common in subduction zones, which are areas where tectonic plates meet and one plate dives under another.

When the seafloor shifts vertically, either rising or sinking, it displaces the water above it and triggers a tsunami. But not every earthquake causes a tsunami. It depends on how big the earthquake is, where it happens, and how deep it is.

For example, an earthquake needs to be pretty strong, usually above magnitude 7.5 and must occur near or under the ocean to cause a tsunami. Earthquakes deep underwater or in places where plates slide past each other sideways usually don’t disturb the ocean enough to create waves.

To understand the visualization of the earthquake that caused the tsunami, you can try imagining  tossing a rock into a calm lake. The ripples that spread out are like a mini version of a tsunami.

Characteristics of Earthquakes that Cause Tsunamis 

Based on the explanation above, we already know that not all earthquakes cause tsunamis. So, how do you distinguish between an earthquake that causes a tsunami and one that doesn't? Let's understand the characteristics! 

1. Magnitudo More Than 7.0

For an earthquake to cause a tsunami, it needs to be very strong, at least a magnitude of 7.0 or higher. Magnitude is basically a measure of how much energy the earthquake releases, and scientists often use the Richter scale to calculate it.

Think of it as a way to rate the “power” of an earthquake. If the quake isn’t powerful enough, it won’t have the energy to move the seafloor enough to disturb the ocean and create giant waves.

But strength isn’t the only thing that matters. The earthquake also needs to be close to the surface, less than 100 kilometers deep. Why? Because shallow earthquakes transfer their energy directly to the seafloor.

When the ocean floor suddenly moves up or down, it pushes or pulls a huge amount of water. That’s what starts the tsunami. If an earthquake happens far below the Earth’s surface or isn’t strong enough, it might shake the ground but won’t create the conditions needed for a tsunami. 

This is why scientists monitor earthquakes closely, especially strong ones near the ocean, to decide if they might lead to dangerous waves.

2. The Earthquake Centered at Sea and Less Than 100 KM Deep

If there is an earthquake with magnitude more than 7, will the earthquake cause a tsunami? Not always. Just because an earthquake has a magnitude over 7.0 doesn’t mean it will cause a tsunami.

The depth of the earthquake matters too. Shallow earthquakes, less than 100 kilometers deep, are more likely to disturb the seafloor and trigger huge waves. Deep earthquakes don’t usually have enough energy at the surface to create a tsunami.

Subduction zones, where two tectonic plates collide, are especially risky. Shallow quakes here can lift or lower the ocean floor, pushing water up or pulling it down to create tsunamis. Without these conditions, even the strongest earthquake may leave the ocean calm.

3. Vertical Earthquake

Not all earthquakes cause tsunamis, even if they are very strong. The key is how the Earth’s crust moves. Earthquakes with vertical deformation, where the ground shifts up or down, are the ones that can trigger tsunamis. This movement pushes or pulls water, creating massive waves.

Some of the worst tsunamis in history, like the 2004 Aceh tsunami and the 2011 Japan tsunami, happened because of this movement. Vertical shifts in the ocean floor pushed water across the sea and caused widespread destruction. Without this type of movement, even strong earthquakes rarely cause tsunamis.

From the explanation above, the question “will the earthquake cause a tsunami” finally answered. Not all earthquakes cause tsunamis. The key factors are magnitude, depth, and vertical movement of the seafloor in subduction zones.