The Mid-Atlantic Ridge – a range of submarine mountains and volcanoes
Magma rises through fissures
Where the ridge rises above sea level, islands such as Iceland are formed
Volcanic vent
(oceanic)
Earth's crust
North American plate moves west
Eurasian plate moves east Convection currents drive the plates apart Mantle
2.5 The Pacific Ring of Fire
Figure 1 shows that active volcanoes and earthquakes occur near the meeting of plate boundaries. The Pacific Ring of Fire is a horseshoe-shaped area containing many plate boundaries. Because of the constant movements of plates, this region is home to almost 75% of the earth’s active volcanoes and is where almost 90% of the world’s earthquakes occur.
Australia g North America
Pacific Ocean
South America
1. The Pacific Ring of Fire
For a video on plate boundaries and the Pacific Ring of Fire, go to YouTube and look up the video ‘Plate Tectonics’ (4:28).
Major plate boundary Strong earthquakes Active volcanoes
1. Why do you think this area is called the Pacific Ring of Fire?
2. Explain why volcanoes are generally found at plate boundaries.
3. Thinking about what you’ve learned so far, and referring to the map on page 5, why do you think Ireland does not have any active volcanoes?
