Deakin Communicating Science 2016

EES 200/101

Earthquake After Effects

From anyone that has experienced an earthquake, or anyone that knows a bit about them – It’s not a good idea to get comfortable, and continue that Netflix n chill sesh after the shaking stops.

If you’re not killed or seriously maimed by an earthquake, don’t you worry! That earthquake most likely generated some other kind of monstrous natural disaster that could finish you off for sure.

Take your pick! There’s the typical landslides, mudslides, and avalanches to be your first points of panic.

The terror of Landslides

Landslides are a typically triggered during or soon after earthquakes, when the earth’s crust is disrupted from the collisions between tectonic plates.

Back in the 1970’s, a landslide with a grand height of around 30m (100 feet) occurred 80 miles away from an earthquake off the coast of Peru. This landslide traveled at speeds greater than 100 miles per hour, plowed through multiple towns, and claimed about 18,000 lives.

BLOG 3 LANDSLIDE

Figure 1. Landslide, 2013, WordPress.com, <https://feww.wordpress.com/tag/taiwan-landslide/&gt;

However… I believe the worst thing brought on by earthquakes are tsunamis.

Origin of Tsunamis

Delving back into Greek Mythology, Poseidon (also known as Neptune according to the Roman pantheon) was the “God of the Sea”. Poseidon was said to have had the powers to shake the earth. Seemingly, an earthquake is often the cause of a tsunami, making this an appropriate power of the sea god.

Tsunami is the Japanese term for harbor wave, but has been adopted into the English language as well. They are often confused with the term tidal wave, but in fact have very little to do with the tides.

Tsunamis are generated by the sudden vertical offset of the ocean floor, initiated by volcanic deformation, submarine landslides, or most commonly, earthquakes.

A wave is created, and it travels away from the origin of disruption. Tsunamis can move at high speeds typically on par with that of an airline jet, and are capable of traveling large distances; they can cross an entire ocean!

Huge earthquakes have occurred in places such as Alaska and Chile, and the resulting tsunamis from the same earthquake have caused deaths in regions as far away as Japan, Hawaii, and California.

When traveling through deep ocean, tsunamis don’t pose much of a threat because they are only about 1m tall. It is only when the wave approaches a land mass that the water then becomes shallower, and gains great height.

 

 

 

 

 

 

Essentially, all the energy of wave is spread evenly as it travels through deep ocean, but as its depth decreases upon the shoreline, the energy becomes more concentrated. Hence, the wave has a dramatic increase in height.

Tsunami damage

In 1800’s, the volcanic eruption of Krakatoa caused the collapse of a caldera – a volcanic crater typically formed by the emptying of the magma chamber beneath a volcano. Following this, a tsunami arose and resulted in 36,000 people being killed on nearby islands.

Tsunamis have caused over 50,000 deaths in the last century alone. And we are only up to the 16th year of this century!

The moral of the story (by that I mean my previous blogs about earthquakes) – don’t live near the edges of tectonic plates.

But in reality, no region is technically safe. If you live on top of a fault line, an earthquake will probably hit you, and if you live more centered on a plate, you can’t hide from the likes of a massive tsunami either!

References:

  1. Ammon, C. J, 2011, Earthquake Effects – Shaking, Landslides, Liquefaction, and Tsnamis, SLU – Department of Geosciences, retrieved 20 April 2016, <http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/earthquake_effects.html>
  2. International Tsunami Information Centre, 2016, How do earthquakes generate tsunamis?, ITIC, retrieved 22 April 2016, <http://itic.ioc-unesco.org/index.php?option=com_content&view=article&id=1158&Itemid=2026>
  3. USGS – Science for changing world, 2015, Caldera, Volcano Hazards Program, retrieved 22 April 2016, <http://www.geology.sdsu.edu/how_volcan oes_work/Calderas.html>
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About isabelle.johnson

One comment on “Earthquake After Effects

  1. kanan
    May 8, 2016

    I have lot of experience of earthquakes but don’t have experience of tsunami fortunately.
    But I have seen many news and video about tsunami.
    Tsunami is 36km/h if depth is 10m and when depth is increases, speed of tsunami also larger.
    (You can calculate speed of tsunami here http://keisan.casio.com/exec/system/1346219493)
    Many people cannot run away and killed by tsunami. That’s one reason of lot of people died.
    And also tsunami is very strong. It breaks houses…
    Look this video that 3.11.2011 earthquake in Japan (https://youtu.be/gluWVySBVOU)
    I was shocked at that time.
    So I recommend you should go a high place ASAP when you hear a warning of Tsunami.

    Like

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This entry was posted on April 26, 2016 by in Geelong - Wednesday 3pm.

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