Tsunami Flashcards
What is a tsunami?
Series of waves caused by displacement of large volume of water.
What four things can cause a tsunami?
Volcanoes.
Earthquakes.
Landslides.
Meteor impact.
Define each:
- wave length
- wave height
- wave period
Wave length: distance from crest to crest.
Wave height: distance from crest to trough.
Wave period: time between passage of two wave crests.
Speed _____ as the wave approaches shore.
Decreases.
When a tsunami approaches shore, what happens to volume and height?
Volume stays the same as the wavelength shortens.
Height increases.
Regarding tsunami, what is run up?
Height that wave reaches as it rushes onshore.
During an earthquake-generated tsunami, wave height is dependent on what?
Vertical movement on fault.
Moment magnitude 8 could generate a _____ m wave at sea.
15.
Describe the process of an earthquale-generated tsunami.
Overriding plate is stuck on subducting plate; plate squeezed, begins bulging up at the end and dragging down towards the subducting plate; gets unstuck, plate relaxes, causes subsidence and sudden uplift causes tsunami.
During an landslide-generated tsunami, wave height is dependent on what?
Primarily height of fall, but also mass of rock/sediment.
Megatsunami typically happen in what areas?
Harbour areas.
In Greenland in 2017, what caused a tsunami?
4.1 earthquake caused landslide.
Describe the tsunami in Valley-Vajont in 1963.
Megatsunami, 50 million cubic metres of water overtopped dam in 250m wave.
What was the lateral and vertical movement of the 2004 Sumatra-Andaman tsunami?
10 m lateral; 5 m vertical.
During the Andaman-Sumatra tsunami, there was a large volume of beach sand over soil. How many cm were there in total, and how much came from the first wave?
73 cm total.
45 cm from first wave.
