How Often Does Hawaii Get Tsunamis?

Hawaii is an incredibly beautiful place that attracts millions of people every year.

Its unique and stunning scenery along with amazing weather and welcoming people have made it one of the most desirable places on the planet to visit. 

But with all this beauty, there is also the lingering threat of a devastating tsunami.

Due to its geographical location, Hawaii is prone to distant and local tsunamis.

Let’s take a look at what a tsunami is, how they happen and how they affect Hawaii. 

Why Do Tsunamis Occur?

Tsunamis mostly happen because of strong or prolonged earthquakes or volcanic eruptions.

The resulting movement of the ocean floor causes long, large waves to form, and move rapidly across the ocean. 

Unlike normal, wind-driven waves, which only move through the uppermost layer of the ocean, a tsunami moves from the ocean floor to the surface as a column of water.

This is one of the reasons why they are so powerful and devastating.

As well as earthquakes and volcanoes, tsunamis can also be caused by landslides or even by certain weather conditions.

Weather generated tsunamis are called meteotsunamis and are still a little understood phenomenon for meteorologists. 

Events thousands of miles away can generate tsunamis.

For example, in 1946 an earthquake off the coast of Alaska caused a tsunami that devastated Hawaii despite being 2,500 miles away. 

Once the tsunami begins to move through the ocean, there is nothing that can stop it.

It is at its most destructive when it reaches shallower waters and land. 

How Many Tsunamis Have Hit Hawaii?

Hawaii is in a unique position in that it can be affected by tsunamis from potentially many sources.

From Alaska to New Zealand, the threat of tsunamis is one that Hawaii has had to confront and deal with for many decades.

Sitting in the deep waters of the Pacific basin surrounded by the infamous Ring of Fire, Hawaii is in a highly active seismic zone.

There are many directions from which a tsunami could and often have affected the islands. 

Since 1812 there have been 142 confirmed tsunamis in Hawaii.

Almost half of tsunamis to reach the islands have been generated from the east of the Pacific, close to the same number came from the west.

Only 7% of the tsunamis were generated locally. 

Around 97% of these tsunamis were caused by earthquakes, the rest by volcanic eruptions. 

What Has Been The Worst Tsunami To Hit Hawaii?

The tsunami that caused the most deaths in Hawaii occurred in April 1946. This was generated by an 8.6 magnitude earthquake off the Aleutian Islands, close to Alaska.

158 people lost their lives and the damage to property and infrastructure was immense. 

Maximum wave heights reached 17 meters on the island of Hawaii, with only slightly lower waves impacting the other islands.

As a result of this awful tragedy, a new respect for the power of a tsunami prompted Hawaii to adopt an early warning system.  

The Pacific Tsunami Warning Center (PTWC) will now issue four levels of alerts depending on the threat.

They range from an Information Statement, through a Watch and then Advisory stage. The final alert is the Warning which advises immediate evacuation. 

Are There Warning Signs Of A Tsunami?

Apart from the alerts issued by PTWC, there are natural warning signs of an imminent tsunami.

These allow you to take immediate action if there has been no public alert. 

The first warning sign is when a strong or prolonged earthquake is felt. This could trigger a tsunami.

The second natural warning sign is if the ocean suddenly draws away from the shore, exposing the sea bed. 

A rise in the level of the ocean is also an indicator of a potential tsunami. Finally, a loud roar from the ocean could indicate that a tsunami is approaching.

Being alert to these warning signs could save your life and allow you to warn others. 

What Should You Do If A Tsunami Is Coming?

If an official warning alert has been issued and a tsunami is imminent, then you should not hesitate to act.

Do not stop to collect possessions or make calls, move to high ground immediately. 

Follow any tsunami evacuation signs and leave the evacuation zone as quickly as possible.

It is not advisable to use a vehicle to try and escape a tsunami, as you may end up getting stuck in a traffic jam. 

Vertical evacuation is recommended if you are in a high rise building. You should climb to the fourth story or higher.

If time allows, you can go to one of the designated evacuation sites which are announced on TV, radio or over social media. 

Although there have been many tsunamis which have affected the islands of Hawaii, it remains a warm and welcoming place full of friendly local people.

They accept that this is part of what it means to live in Hawaii and give the ocean and earth a healthy respect. 

You shouldn’t let the islands’ history of tsunamis deter you from visiting this tropical paradise.