- The best way to protect ourselves is by educating ourselves. Know what we can do now to prepare for a tsunami, know what to do during a tsunami, and know what to do after a tsunami. First, let’s find out what they are and how they are formed.
Tsunamis are a series of waves usually generated by a major earthquake beneath the ocean floor or major landslides into the ocean. Earthquake induced tsunamis are caused when the plates slide against each other which causes friction and the plate to fracture. This sudden vertical movement of the seafloor transfers the energy from the solid earth to the ocean which creates the waves.
The resulting crest can be as small as a few centimeters all the way up to several meters in height and the time in between crests can range from minutes to hours. When the tsunami enters shallow water, they may rise to several feet and destroy everything in its path when it hits land (as witnessed from the 2004 tsunami in Indonesia and the more recent 2011 tsunami in Japan)
Tsunamis Are Deadly
The deadliest tsunami was said to have killed an estimated 300,000 to 500,000 in Crete, Greece on July 21, 365. Yes, that was a LONG time ago but the next one is quite recent. The next deadliest was the more recent one in Indonesia that occurred on December 26, 2004 and killed 280,000. Those are INCREDIBLE numbers! Can you even imagine that many people? Most people near the coast had no chance as the tsunami quickly engulfed the land with waves as high as 100 ft (39 meters). It all happened so unexpectedly that even initial survivors passed away due to their wounds and lack of supplies. The more recent tsunami in Japan caused a lot of damage as a nuclear reactor failed which they still haven’t been able to fix.
Tsunami warnings are getting much more efficient. Since warning systems were first put in place back in 1948, technology has advanced in tsunami detection so much that we’re now available to detect whether there will be a tsunami threat after an earthquake within minutes instead of hours. They do this by using strategically placed sensors on the ocean floor which detect pressure changes then transmit the data to surface buoys. The data then is immediately transmitted from the satellite to ground stations for analysis. If a tsunami is imminent, they will go through the proper channels to alert authorities who in turn alert us via radio, TV, telephone, text message, door-to-door contact, social media, or outdoor sirens.
You should know about 2 potential signs of a tsunami.
- Be very cautious if there was a strong earthquake lasting 20 seconds or more near the coast.
- A rapid change in the height of coastal waters
If any of the above occur, IMMEDIATELY go to higher ground or if you can’t, you should move inland as far as possible and stay AWAY from the beach. Don’t go to the beach so you can “watch” the tsunami. Chances are you’ll be swept away and you won’t have time to get away.
Now that we know what a tsunami is, how it’s made and a few potential signs of it, read the next post to see what we can do now to prepare for one.