Earthquakes
where do 80% of all earthquakes in the world occur
Pacific ring of fire
Where do 75% of all volcanoes occur?
Pacific Ring of Fire
Who came up with the concept of Seafloor Spreading?
Harry Hess, 1960
Molten rock on the outside of a volcano is called
Lava
On average, how many earthquakes occur each year?
500 000
Where and what year was the strongest earthquake ever recorded?
Valdivia, Chile. 1960.
Name three types of volcanoes?
Shield
Stratovolcano
Caldera
What boundary does seafloor spreading occur at?
Divergent
What is molten rock inside a volcano is called
Magma
How many people die on average thanks to earthquakes
10 000
What type of plate boundaries do earthquakes occur?
All
This volcano has thin runny lave that flows very fast.
Shield Volcano
In seafloor spreading, where are old rocks found?
on the outside, coast
The top of a volcano that usually forms a depression is called
Crater
What plate boundary do volcanoes occur?
Convergent
Earthquakes are measure in moment of Magnitude. This is a logarithmic scale. What does that mean?
It goes up by X10
This volcano has thick sticky lava that oozes
Stratovolcano
What type of land feature does seafloor spreading form?
Mid ocean ridge
When a volcano erupts a magma flows out of what
either the main vent or vent
How many active volcanoes are there in the world
1500
Which type of boundary do the most destructive earthquakes occur at?
Convergent/transform
What does the Explsoivity Index scale measure when a volcano erupts?
Gas plum, amount of lava
Name two types of evidence of seafloor spreading?
Age of rocks
Magnetic stripping
Where is Australia's only active volcano located?
Heard Island called Big Ben
Why does seafloor spreading occur
Convection currents in the mantle