Tsunamis are enormous waves that can devastate coastlines and cause massive damage to both infrastructure and humans. Around 200 tsunamis were recorded from 1900-2000. The most common cause of a Tsunami is an earthquake under the sea. But all earthquakes do not result in tsunamis. Tsunamis can also be created by other sources than earthquakes like volcanic eruptions, landslides and impacts by space objects like asteroids. The water above the earthquake absorbs the energy and creating a tsunami. On the open ocean a tsunami wave is often not higher than a few meter, but when it reaches more shallow water of a coastline the wave can reach a height over ten meters. A Tsunami travels very fast over the open ocean, so the time before it strikes coastlines after an earthquake takes place can be short. A tsunami wave is not a short big wave but a very long wave that can cause devastation for up to half an hour before it goes away. The effects of Tsunamis are increased since a very high part of the human population in the world lives near coastlines. It’s also very common that people from other countries visit warm countries as tourists and spend their time near the beaches and coastlines.
Timeline and Historical Examples
During the 1755 Lisbon earthquake the city was not only affected by a devastating earthquake, tsunami waves also added to the destruction. Many from the city fled to the beaches only to be struck by these waves.
1883 There was an enormous volcanic eruptions on the island Krakatoa. The Eruption almost destroyed the entire island and the debris from the eruption created tsunami waves that killed many people far from the eruption. Over 30.000 are believed to have died from the eruption and the tsunami waves.
1896 A powerful earthquake took place outside the coast of Japan. The earthquake created a powerful Tsunami that killed around 25.000-30.000 people, destroyed around 10.000 homes and left many wounded.
1958 an earthquakes created a powerful tsunami that reached an enormous height in Lituya Bay, Alaska. A combination of factors resulted in the wave reaching a height of 520m in the bay.
The 1960 Valdivia earthquake caused a tsunami that killed people in a number of place including Chile, Japan and Hawaii. 2000-6000 died and there was damage for hundreds of millions of dollars. Around 60 of the deaths were in Hawaii.
1964 the powerful earthquake on Good Friday resulted in Tsunami waves in Alaska that killed around 130 people, most of them for the tsunami waves. The tsunami also caused damage for millions of dollar in Canada.
1995 a Tsunami hit Japan resulting in around 6000 dead. The Tsunami was caused by an earthquake measuring 6,8 on the Richter Scale.
1998 an earthquake outside of Papua New Guinea caused an tsunami that killed around 2200, Many villages was destroyed and around 10.000 became homeless.
The 2004 Tsunami in the Indian Ocean was caused by an earthquake with and magnitude of 9,1. The earthquake that caused the tsunami was the one of most powerful earthquake that’s ever been recorded. 13 countries were hit by the tsunami. Over 200.000 were killed as a direct effect, around two million became homeless and there was massive damage to infrastructure and the fishing industry. The exact number of dead will never be known, many of the dead may never be found as they were washed out into the ocean.
Survival and Preparedness
Some regions encounter tsunamis relatively often and have very well functioning systems for early warning. The Pacific Tsunami Warning System that is located on Hawaii is one example. If you live in an area where tsunamis are common make sure that you know how the warning systems operate. In some places high walls have been constructed to protect densely populated cities near the coat lines. A typical sign of tsunamis is that the water level in the ocean suddenly withdraws below normal low water levels. This is a typical warning sign and must be taken seriously at once. If a tsunami is about to hit you must get to the highest most stable ground that you find immediately.
During many of the historical tsunamis the damage caused has been relatively low compared to other natural disasters, but the 2004 event in the Indian Ocean was a drastic exception. In this case the damage caused was enormous and it took some time before the extent of the damage became clear for the people in charge of different national and international crisis management agencies.
The location of your home is a very important part if you live in an area that can be affected by a Tsunami. If your house is likely to be affected in case of a major tsunami, where do you seek cover and how will you get there? A house near the ocean may have a very nice view but the danger from possible tsunamis and hurricanes should be taken into account. These plans should be a part of your personal Risk Assessment.
Even if you are not directly affected by an Tsunami it can still cause disruptions to communications, transport and infrastructure. Having some basic items as your Every Day Carry or a Get Home Bag may provide you with the basic needs that you might need, light and some First Aid Supplies.