Earthquakes, Volcanos, Tsunamis Flashcards
Name the seven main plates
Indian plate African plate Australian plate Eurasian plate American plate Nazca plate Pacific plate
What sort of activity can take place at plate boundaries
Volcanic
Earthquakes
Mountain building
Why do the plates move on the magma
The core heats up the magma in the mantle and this sets up convection currents
What was the super continent called before continental drift
Pangea
Where does volcanic activity take place
Most of the time it’s on plate boundaries
What is a mid-ocean ridge
A chain of mountains underwater
Give an example of a mid-ocean ridge
The mid Atlantic ridge and it’s about 16000km long
How are mid ocean ridges formed
When two plates separate magma rises from the mantle through cracks or fissures of the crust between the two plates. When the magma reaches the water it cools and solidifies to form a new ocean floor. This happens over and over again to form a chain of mountains under the sea
Give an example of a volcanic island
Iceland
How are volcanic mountains formed
They are formed when magma form a hole in the crust called a vent as the magma is under so much pressure in the mantle most eruptions are violent.
Where are volcanic mountains usually placed
On plate boundaries
What erupts from a volcanic mountain
Magma,ash, has, rocks, steam and boiling mud
What is an active volcano and give an example
A volcano that is still erupting at regular intervals
Ex: mount Etna, Mount St. Helens
What is a dormant volcano and give an example
A volcano that hasn’t erupted in a few hundred years but may still erupt in the future
Ex: Mount St. Helens was a dormant volcano until it erupted in 1980
Or Mount Fuji is still active but has not erupted since 1707
What is an extinct volcano and give an example
A volcano that hasn’t erupted in recorded times (thousands of years)
Ex: Slemish mountain co. Antrim
