A Greek Recipe for a Big Wave

τσουνάμι
Tsunami (Greek)

Hey there! My name is Sierra and I am currently studying the geologic hazards associated with Santorini, Greece. As a class we’ve hiked basement rock, sketched a cinder cone, and observed ash deposits – all clear remnants of volcanic activity. One hazard you may not be quick to think of is tsunami, but being an island, the risk is always there. Don’t worry though, I’ve included a quick recipe to reference from home:

Start off with two Tectonic Plates:

Earth’s crust is broken up into many small sections, referred to as “plates”. These plates are like puzzle pieces of rock that are constantly moving and sliding past, under, above, and into each other. The areas where these plates meet are called “plate boundaries” and occur all over the globe as seen by the orange lines on the map.

Add in a pinch of Subduction:

Due to the constantly moving nature of crustal plates, they do not quite fit together without some interaction. When one plate is thinner and heavier it may slide beneath another plate, this is called “subduction”. As the plate slides beneath, sections can become “stuck” and this accumulates strain overtime. This strain is then stored within the rock plates themselves, until it is released in the form of an earthquake.

Choose your Flavor:

Tsunami are caused by the mass movement of water, or water displacement. This can be caused by a variety of processes such as landslides and rockfall; volcanic eruptions; and earthquakes which all move large amounts of water out of the way, resulting in a massive wave. Earthquake-triggered tsunami (my favorite – very spicy) are a result of elastic rebound which is when crunched rocks (a side-effect of subduction’s strain) snap back into place – shoving water out of the way and forming a tsunami wave.

A Greek Twist:

Santorini is just north of an active subduction zone within the Aegean sea, this makes it susceptible to earthquake triggered tsunami. These earthquakes can also dislodge loose sediment and rocks on the island, increasing risk for rockfall related tsunami. Although it is not currently erupting, Santorini is also at risk of volcanism-based tsunami due to its potential for volcanic eruptions.
Santorini is well known for white cities built in the cliffs, seemingly far away from the threat of tall waves. However, the exterior coastlines are mostly low-lying and vulnerable to wave run-up as tsunami waves make contact with the shoreline and the wave floods up onto the dry land. This run-up distance is controlled by wave height as well as human and natural barriers and funnels such as thin streets, buildings, flood walls, hills, and paved surfaces which can limit or further the wave movement over land. The area seen in red is land lower than 100m above sea level, which could all be susceptible to tsunami impact – although waves could reach further inland or stay nearer to shore depending on exact size.  

Although it may not be the most appetizing side-dish to your Greek vacation, it is important to be aware of tsunami in the Aegean and the mechanics behind their formation.

6 thoughts on “A Greek Recipe for a Big Wave

  1. Great post! The visuals were really clear and informative. You did a good job of simplifying the more complex scientific concepts so anyone reading can understand!

    1. Thanks, Viola! It’s crazy and exciting how much science can tell us about the processes happening around us!

  2. Very cool post Sierra! Well done and a great expanation of tsunamis in general. It was nice to be reminded that tsunamis can be generated in more than one way. When i hear the word “tsunami”, I usually think of an earthquake that causes the seafloor to shift, but landslides and volcanic eruptions are just as capable of displacing water and generating a tsunami. It’s good to keep all of these risks in mind!

    1. Thank you for taking the time to read and comment on my blog post, Mike! Learning that earthquakes are not the only trigger of tsunami has been an exciting thing I’ve learned and I’m glad I was able to slide it into this blog post.

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