Tsunamis are some of the most destructive natural disasters in the world. They can reach heights of up to 100 feet and travel at speeds of up to 500 miles per hour. In just a few minutes, they can devastate coastal communities with waves of water that can sweep away everything in their path.
Despite their power, there are ways to survive a tsunami. If you are near the coast when a tsunami warning is issued, evacuate immediately. Go as high and as far inland as possible. If you can’t get inland, go to higher ground on the coast. Never try to outrun a tsunami.
What Is a Tsunami?
A tsunami is a series of destructive waves resulting from a sudden displacement of water near to the seafloor.
These waves can be anywhere from hundreds of miles long and massive to no taller than a few feet. As the waves reach the coast, they slow down to 20 – 30 mph, but grow substantially in height, to anywhere from 10 – 100 feet.
Tsunamis can cause immense destruction to the coastal areas they hit in the form of floods and powerful currents that last for hours or days, and come in a series of surges.
Tsunamis radiate outward from their point of origin, with the biggest ones causing damage over a thousand kilometres from where they originated (for example, the Tsunami that hit Japan in 2011 had effects that were seen as far as the coast of California).
Where Does the Term “Tsunami” Come From?
The term “tsunami” comes from the Japanese characters “tsu” (harbour) and “name” (wave).
This comes from the past where fisherman would go out to sea and not experience anything unusual, only to come back and find that their villages had been devastated by a huge wave (i.e., a wave that only hits the harbour).
What Causes a Tsunami?
Most tsunamis are caused by underwater seismic activity such as when an earthquake displaces a large amount of water near the seafloor.
Earthquakes are not the only thing that can cause a tsunami. Other known causes include undersea volcanic eruptions, landslides, and even meteorites.
Where do Tsunamis Usually Occur?
Tsunami’s occur in the Pacific Ocean accounting for 71% of all the global total.
According to the National Weather Service “The largest number of earthquakes occur around the rim of the Pacific Ocean associated with a series of volcanoes and deep-ocean trenches known as the “Ring of Fire”.”
can occur in any of the earth’s oceans or other large bodies of water, and have affected coastal areas all around the world in the past.
It is therefore vital to remain vigilant for a tsunami whenever you are living or staying in a coastal region.
That being said, there are certain regions that are at especially high risk of being hit by a tsunami, and of experiencing more damage when they are hit.
Factors such as proximity to tsunami sources, the shape and depth of the ocean floor near to the coast (bathymetry), and elevation and other features of the land (topography), all have an impact on the level of risk of a particular place.
Since 1900, almost 80% of all tsunamis had their source in the Pacific Ocean’s seismically active belt known as the “Ring of Fire”.
Japan has experienced the highest percentage of tsunamis (21%) followed by Russia (8%) and Indonesia (8%). Most of the hundreds of tsunamis that have occurred in this period are relatively small and non-destructive, but about twice every decade, the world experiences a “distant” tsunami which can cause catastrophic damage on distant shores more than 1000 kilometres away.
How To Be Prepared for a Tsunami?
In order to have the best chance of surviving a tsunami if it hits, it is vital to be prepared beforehand.
It is easy to be complacent and simply think that it will never happen to you, but this kind of attitude could leave you in serious trouble if you are in a danger zone and faced with a very real tsunami heading your way.
Tourists are most at risk of being unprepared for a tsunami, as it is the last thing you want to think about when going on a tropical holiday. However, if you are travelling to a known tsunami hotspot, it is important to take the necessary precautions.
You must stay alert to any tsunami warnings made by local authorities and familiarise yourself with the steps to take if you are faced with one.
In order to be properly prepared for a tsunami you should:
1. Learn how to identify the signs of a potential tsunami.
The majority of tsunamis are triggered by earthquakes, so if there is an earthquake and you are staying in a coastal tsunami region, you should immediately move to higher ground inland after the earthquake stops to be on the safe side.
Do not wait for official warnings, as time is of the essence. Other tell-tale signs of an incoming tsunami include a loud roaring sound coming from the ocean, or a sudden receding of the water exposing the ocean floor.
2. Familiarise yourself with the evacuation protocol and routes in the community that you are staying in.
The level of sophistication of tsunami evacuation plans and warning systems vary depending on where you are in the world. Some may have comprehensive routes mapped out with various tsunami shelters such as strong towers, buildings, etc., while underdeveloped areas may be less prepared. Understand the best way to deal with a Tsunami in the area you are staying in.
3. Establish a family emergency communication plan in the event of a tsunami.
This should include a common contact person outside of the area, as well as a meeting point if you get separated.
4. Stay up to date with local news reports and public warnings.
You may also sign up for your community’s warning system, as well as nationwide emergency alerts such as Emergency Alert System (EAS) and National Oceanic and Atmospheric Administration (NOAA) Weather Radio.
5. Consider taking out an earthquake and/or flood insurance policy
If you are worried about a tsunami and the damage it could cause to your home and livelihood you might want to get some insurance. Ordinary homeowner’s insurance does not usually cover flood or earthquake damages.
How to Survive During a Tsunami?
1. Take Cover If There is An Earthquake
The vast majority of tsunamis are caused by undersea earthquakes. This means that there is a high chance you will be faced with an earthquake danger if its effects are felt inland. It is your first priority to protect yourself from the earthquake before considering a potential tsunami.
To protect yourself during an earthquake, use the standard “drop, cover, and hold on!” Drop to the ground on your hands and knees, cover your head and neck with your arms, and hold on to any stable furniture or other structure until the shaking stops.
2. Evacuate to Higher Ground
When the immediate danger of the earthquake has subsided and you are safe, you should immediately consider the possibility of an incoming tsunami. An earthquake comes with a high risk of a subsequent tsunami, so in such a case you should immediately begin to evacuate as a precaution without waiting for an official warning.
In other cases, you may not feel an earthquake, in which case you should be on the lookout for other natural signs of a tsunami (receding ocean, roaring sound coming from the ocean, etc.) or pay attention to official tsunami warnings. If either of these occur, you should also evacuate immediately.
When evacuating, the objective is to move as high and as far inland as quickly as possible.
The ideal is to find a place 100 feet above sea level or two miles inland from the ocean. Many tsunami hazard zones have evacuation signs to guide you to safety along the best route. Evacuate on foot so as to not get stuck in a vehicle.
Take a light pack with emergency supplies such as some food, water, first aid, flashlight, etc. Tsunamis can strike very quickly after an earthquake, so do not delay your evacuation at all.
If you are situated outside of the tsunami hazard zone and hear tsunami warnings, you may stay where you are unless you are told by officials to evacuate.
3. Find Shelter If You Are Unable to Evacuate
Tsunamis can happen suddenly and rapidly. You may unfortunately be in a situation where you do not enough time to evacuate to a safe area. In this case, you should find the best shelter you can in your immediate vicinity.
Climb as high as you can up a tall and sturdy structure.
The third story or higher of a strong building is a good choice. Some tsunami hazard zones will have constructed special vertical tsunami shelters in strategic locations, which are strong enough to withstand the power of the water and tall enough to provide safety.
Familiarise yourself with the locations of these shelters and head straight for one of them if you are in immediate danger of a tsunami. If you can already see the water coming you are too late to evacuate and should take shelter instead.
4. Go Out to Sea if You’re in a Boat
If you are in a boat, it is much safer to face the waves and head out to sea rather than returning inland.
The waves of a tsunami are most dangerous and large near to the coast, so the further out at sea you are the safer you will be. If you are in the harbour, then immediately go inland and do not try to head out to sea.
5. Hold on Tight
If all of the above measures fail and you find yourself caught in the tsunami waters, try to grab onto something that floats and hold on tight.
A raft, tree trunk, or any floating debris will do. Do not swallow any water as there may be toxic chemicals that have been swept up in the currents.
There is really not much else you can do once you are trapped in the powerful waters and currents.
Survival is mostly down to luck at this point, as no one can swim their way out of a tsunami. It will be more or less a swirling soup of debris in which there is the high risk of getting crushed or knocked under the water. Try to not panic, hold on, and hope that you will be carried to safety. Easier said than done of course.
6. Stay Put
If you managed to evacuate the tsunami or find a secure shelter, it is important that you stay put there after the first wave has passed.
Tsunamis come in multiple surges which can last up to 8 hours or more, so you must stay in your place of safety for at least this long or until you are given the all clear by emergency officials. Even then, you should return to lower land with caution, as even official tsunami warning authorities have made mistakes in the past.
What to Do After a Tsunami Has Hit?
As mentioned, tsunamis can last a long time and come in multiple waves. Even after it is finally safe to leave your shelter, you should pay attention to local alerts about safe areas and those to avoid. Keep in mind the following key points:
- A tsunami may have weakened buildings and other structures, so you should proceed with great caution. Avoid any damaged roads, buildings, or other structures.
- There could be downed power lines and a high risk of electrocution and avoid wading through any floodwater or touching wet electrical equipment.
- Phone systems may be down or congested, so save phone calls for emergencies and use text messages and social media to communicate with your loved ones.
- Contact emergency services if you or someone in your party is sick or injured. Try to treat any small wounds or minor injuries with whatever first aid equipment available while you wait for medical assistance.
- Take photos of property damage and conduct an inventory check to provide to your insurance company.
If you are currently living in an area that is at high risk of experiencing a tsunami, or you find yourself in one at any point, you should take the necessary steps to prepare yourself ahead of time for this potential disaster.
When you are faced with the actual fact of a tsunami headed your way, you will have very little time to think about what to do.
You must be well rehearsed in how to handle the situation so as to give you and your loved ones the best chance of survival. Hopefully it is something you never actually have to deal with, but its certainly not worth taking the chance of being unprepared.