Earthquakes, Volcanos, Tsunamis Flashcards
(37 cards)
Name the seven main plates
Indian plate African plate Australian plate Eurasian plate American plate Nazca plate Pacific plate
How many main plates are there
Seven
What sort of boundary is it if two plates pull apart
Constructive boundary
What sort of boundary is it if two plates collide
Destructive boundary
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
Where are more than half of the worlds volcanos located
The pacific ring of fire
What is an earthquake
A sudden trembling of the earths crust and this takes the form of a series of shocks and tremors
What is the focus of an earthquake.
The point deep in the earths crust where the earthquakes begin
What is the epicentre of an earthquake
The point directly above the focus on the surface. It’s the place where the tremors are the strongest
What scale is used to describe the damag e or strength of an earthquake
The Richter scale
What is the instrument used to measure the strength of an earthquake
Seismograph
