Why Does Japan Have Tsunamis?

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I come from Singapore where it’s quiet and peaceful all year round when it comes to natural disasters. I never realized how much I took that for granted until I moved to Japan, where the dramatic forces of nature are the norm. It took me a while to get used to that — I bet others, who were in a similar position as me, had to as well.

The Land of the Rising Sun is not all neon city lights and ramen — there are days where the people here are overwhelmed by feelings of fear and distress instead of exhilaration and euphoria. The main suspects that bring those emotions out are frequent natural disasters including tsunamis that disrupt daily lives and tragically take some away — as when the major tsunami that struck Japan in 2011. But what makes this island nation different from others to be on the recurring receiving end of such natural forces?

Japan is not randomly chosen nor volunteered to be acquainted with these sizeable waves. Read on to find out the reasons for the periodic risks and occurrences of a tsunami in Japan — as well as what to do if you happen to be in a situation of tsunami risk, regardless of whether you’re in Japan or not.

Why Does Japan Have Tsunamis?

How Are Tsunamis Created?

Normal waves are formed when energy passes through the water, and that causes it to move in a circular motion. Wind can also create waves — this happens when there’s friction between the surface water and wind, causing a continual disturbance and thus result in surface waves. Another type of wave is the tidal wave, created by the gravitational effects of the sun and moon on the earth.

Tsunamis consist of waves — huge, tall, unimaginably strong ones. They’re nothing like normal waves and aren’t caused by the wind or tides like some normal waves. Tsunami waves are formed when there are disruptions that are ginormous, including but not limited to earthquakes, volcanic eruptions, and landslides that occur under the sea. Large volumes of water move together at full depth in a speed you didn’t think water could — in fact, water can move as fast as a jet plane when in deep oceans.

When the water absorbs energy from these drastic disturbances, they travel inland and the volumes of water constantly pile up. By the time it reaches the shore, the waves build up a consistent wall of water that can dangerously be taller than some buildings!

Most of the time, water from the shoreline will recede — this is known as a drawback. The drawback is one of the warning signs that a tsunami is approaching the shoreline. Even though it is an early warning, that doesn’t mean one should take their time. The time between the seawater receding and the full tsunami moving inshore is usually a few seconds to a few minutes — and the latter is a best-case scenario. That’s because the drawback is the indication that the tsunami wave is through half of its cycle.

Why Does Japan Have Tsunamis?

Japan’s Tsunami History

Japan has quite a history of tsunamis. Since 684, there have been a total of 141 waves that are classified as a tsunami. About 130,000 deaths have been recorded due to tsunamis in the country. 

The strongest one ever recorded occurred in 1741 caused by a volcano in northern Hokkaido with a magnitude 6.9 earthquake. The tsunami reached a height of 90 meters and took the lives of 1,607 people. Even though it’s the biggest one, it wasn’t the one that took the most lives. In 1498, an earthquake of 8.3 magnitude caused a tsunami of 10 meters and killed 31,201 people.

Yet the one that impacted Japan the most in terms of not only lives but also agriculture, development, and the economy, was the tsunami in 2011. This devastating disaster wasn’t fully predicted — scientists had forecasted a smaller earthquake. On March 11th of that year, a 9.1 magnitude earthquake unleashed a tsunami of 55 meters tall in Japan. The tsunami wave was so big that it reached 11 neighboring countries. A total of 15,894 deaths in Japan was confirmed with thousands more in other countries.

The tsunami hit Miyako City 39 meters inland and traveled as far as 10 km in Sendai. The disaster also flooded approximately 561 square kilometers of land in Japan. Tsunami sea walls were toppled, more than 120,000 buildings were fully destroyed, over a million partially destroyed, and a huge whirlpool near Oarai was generated. This tsunami was the costliest natural disaster in world history, reaching up to $235 billion in damages.

Why Does Japan Have Tsunamis?

Why Does Japan Have Frequent Tsunamis?

There’s a saying about being in the right place at the right time. Well, Japan is located in the wrong place… all the time. This island nation is along the “Pacific Ring of Fire” — an imaginary horseshoe-shaped zone that is on the rim of the Pacific Ocean. This is where it’s the most active for earthquakes and volcano eruptions. What’s more, Japan is smacked on top of four shifting pieces of Earth’s crust known as the tectonic plates that mash and collide. 

Because of the country’s location, Japan has about 1,500 earthquakes every year even though some of them don’t go any bigger than 3.9 magnitude. In some areas of Japan, the people that live there might even tell you that they experience earthquakes every few days or so.

Why Does Japan Have Tsunamis?

Tsunami Warning Categories in Japan

Japan is as prepared as any country can be if they’re exposed to such frequent natural disasters, especially potential tragic ones that may destroy and take lives. The country has set up three categories of warnings exclusively for a tsunami. Each one is for a range of tsunami heights — under each category, it’s stated what actions must be taken and what damages should people expect.

The first category is the Tsunami Advisory. This is when the tsunami is expected to be up to only 1 meter in height. When this warning is issued, anyone who is exposed offshore may be caught in strong currents into the sea. Fish farming facilities as well as small vessels like boats may be washed away or capsized.

The second category is the Tsunami Warning. This warning will be issued when the expected tsunami is to be from 1 meter to 3 meters in height. The tsunami waves are expected to hit — and hit hard. Low-lying areas will be damaged and buildings will be flooded. People are advised to evacuate the coastal as well as river areas to higher ground or a tsunami evacuation buildings — those who are exposed will be caught in the strong currents.

The third and last category is for tsunami waves over the height of 3 meters: Major Tsunami Warning. This warning is for a type of tsunami that is expected to completely destroy wooden structures, deeming it to be extremely strong. Similarly, people are strongly advised to evacuate coastal areas as well as river areas to higher ground or a tsunami evacuation building. 

One thing you should note is that, even though there are tsunami warning systems, they might not be issued early enough for evacuation — especially when it’s the Major Tsunami Warning as this is when the wave of the tsunami comes at extreme speeds inland.

Why Does Japan Have Tsunamis?

What To Do If A Tsunami Strikes?

Not all of us are prepared for such a natural disaster. Maybe some of us are from countries where tsunamis occur too, but nowhere is more prone to these huge waves than Japan. Regardless, it’s best to know what to do if a tsunami — of any height level — hits, especially if you’re traveling to Japan for the first time. 

1. Do not panic

The first thing you should do is not panic. When we’re overwhelmed with such emotions, we won’t be thinking straight and end up making rash decisions. Try to keep calm and recall the procedures to take for a tsunami strike.

Keep in mind that tsunami waves can crash inland at unexpected times — even if you see it far out the sea, chances are they’re moving really fast. Don’t panic pack — that’s when your first instinct is to take all your precious belongings with you. The most precious thing is your life, so leave the first chance you get.

2. Higher, not further

Instead of going to a place further inland — which is the most instinctive thing you think of doing, especially when you’re in a panic state — go higher up. Tsunami waves can reach heights of more than 10 meters and tsunami evacuation sites might be dangerous places to be. But the taller it is, the more distance inland it will cover. Tsunamis can reach quite a distance inland but you’re much more likely to be safer if you’re higher off the ground than further into the city. 

If you are seeking refuge at the evacuation site, that is still okay too. They’re made especially for that reason: to be a safe place in times like these. When you are at one, do not leave the site. A tsunami is not just one single wave but a series of them. The intervals between them can be seconds or even hours apart — during this time when the tsunami warning is issued, do not return to the threatened areas. Wait it out.

3. Rivers are threats, too

Even if you’re not by the ocean or other coastal areas, you might still be at risk when a tsunami strikes — especially if you’re near a river. The waves from the tsunami can travel up rivers and streams, putting those near these areas at risk. Floods can occur as well, so seek refuge at higher ground or a tsunami evacuation site.

Why Does Japan Have Tsunamis?

Be Informed, Be Prepared

Japan has the highest threats for a tsunami, and that’s unfortunate — it’s unchangeable. What we can change is how we perceive it and how we react to it to save our lives and the lives of others. Don’t let the proneness to natural disasters in Japan scare you off from visiting (or even living) in the country — this island nation is a wonderful place to be with measures taken to prevent the forces of nature affecting everyday lives as much as possible.

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