Tsunami (Japanese Harbor wave)

  • Tsunami
    • Origen: Seismic sea wave; displacement of a large volume of water normally in the ocean
    • Trigger: Caused by submarine earthquakes, under water detonations, land slide, large impacts in sea and volcanic eruption
      • Three origins:
        1. Sea floor deformation; vertical displacement
        2. Tectonic earthquake; earth crust deformation. Overriding plate (OP) is stuck in the subducting plate (SP). Slowly the plates create an elevation of OP. When OP slams down to SP we get a big Tsunami
        3. Landslide
      • Danger: High speed water and destructive power; debris and a lot of water. Deadly!
      • Behaviour: Sudden onset and difficult to get away
      • Place: Lake; normally deep and cold with organic matter; often holomitic (mix of layers)
      • Other: It is difficult to predict, and devastating
        • Normal wave: Only superficial parts of the water moves
        • Undersea current: Deep parts of water moves
        • Tsunami: All the water move; resemble a rising tide – no breaking of the water
          • Distance: Cross oceans
          • Height: 5-20 meters (highest registered 524 meters)
          • Width: hundreds of kilometers
          • Speed: up to 800 km/h
          • Wave period: about 12 minutes
          • NB! Gain height in shallow water; from 3 m to 30 meters
      • Precaution: Be careful when in risk areas.
      • Main indicator: Drawback of water with a strange sound
          • Seek higher grounds
      • Closedown of Society: Fast and long lasting




WFET on Tsunami

We need to be more conscious about where we are. If we are in a risk area, then we should be conscious about where we stay. Tsunamis are relatively rare, but happen from time to time. Ask local people about tsunamis in the area where you are. They will give information about risk areas and safer areas. Often an earthquake in the sea is followed by a tsunami.  You will have no solid information before the tsunami starts moving towards you. That is why you have to plan; plan BEFORE the emergency.

This is called to make your emergency plan. That is IF the worst case scenario happens, a Tsunami. What do you do? First you need to set your parameters; where is it more dangerous to be if it happen an eruption?  Divide into different zones red, yellow and green. When you move into a yellow zone you need to have a way out if something happen or a safe place to hide. Here a safe place might be something high or a type of water proof-bunker. When moving into red zone you need to me on 100% alert, have a pre-defined way out and pre-defined clues for you to pull out. If it is possible define safe zones to use IF you cannot get out. This type of safe zones is not 100% safe, but might work as a type of protection. Perhaps most important than everything, STAY CALM!