Science Focus Topic 6 Notes: Volcanoes | Print |
A volcano is an opening in the Earth's crust that releases lava, steam and ash when it erupts (becomes active). The openings are called vents. When volcanoes are not active, they are called dormant.

Famous Volcaoes

- the eruption of Mt. Etna in Italy this past summer shows that volcanoes cannot be predicted and don't always behave in ways scientists think they will behave. They can be rather spectacular (as the video link shows).
- the most active volcano on the Earth is
Kilauea in Hawaii (Loihi is a new volcano forming beside the main island in Hawaii - creating a new island)
Krakatau, in Indonesia (blast was heard 4800km away and tsunamis waves were 30 m high)
Mount St. Helens, in Washinton (sideways and vertical eruptions)
Mount Vesuvius, in southern Italy (City of Pompeii was buried - it is due for another large eruption because it is sealed with a 'rock plug' that could blast 1.5 km upwards)
Mount Pinatubo, in the Phillipines (ash circled the globe and cooled temperatures around the world)

Current Volcano update:
- volcanoes that form a circle around the Pacific Ocean are called the
Ring of Fire (derived from the circle of volcanoes that pour out red hot lava, fire and steam)


- Volcanoes on Lo, one of Jupiter's moons have been photographed using Vidicon - a type of TV camera mounted on the Voyager spacecraft, using an electron gun and photoconductor
- those on
Mars and our moon have been extinct for millions of years, while those on Venus may still be erupting
- the largest volcano found in our universe is the extinct
Olympus Mons on Mars