By Claire and Demos

A volcano is an opening in a planet's surface which allows molten rock, ash and gases to escape from below the planet’s surface. The word ’volcano’ is taken from Vulcan, the Roman god of fire.

There are also mud and ice volcanoes not to mention super volcanoes, cinder cones and composite volcanoes. There

are also submarine, subglacial and shield volcanoes as well as lava domes, crypto domes and fissure vents.

Here are some pictures of different types of volcanoes.

Subglacial Volcano

Shield Volcano

Lava Dome

Mud Volcano

Super Volcano

Ice Volcano

Some volcanoes occur when two plates meet. When two plates collide and one plate is forced

beneath the other plate, the friction makes the first melt and magma rises up. Only some volcanoes on earth are formed like this, but their eruptions are

the most violent and are the most dangerous.

Underwater Volcanoes are formed when the surface of the Earth tears apart. The ocean surface is congested and creates pressure on the surface which concludes in the surface actually cracking

forming an underwater volcano.

When you measure the magnitude of an earthquake you are measuring the size and the extent of it. The magnitude of an earthquake is measured on the Richter magnitude scale. This

scale is also known as the local magnitude. This scale assigns a single number to express the amount of built up

stress released by an earthquake. The effective limit of measurement for local magnitude ML is about 6.8. Even though

the Richter scale is still used it has been replaced with the moment magnitude which conveys similar results.

Did you know that an earthquake that measures 5.0 on the Richter scale is ten times larger than

one that is measured at 4.0?

Richter Magnitude

Description Earthquake Effects

Frequency of

occurrence

Less than 2.0

2.0 to 2.9

3.0 to 3.9

4.0 to 4.9

Micro

Minor

Minor

Light

Micro earthquake

not felt.

About 1,000 each year.

Often felt but rarely

causes damage.

Generally not felt but still

recorded.

49,00 each year.

Noticeable shaking of

indoor items, rattling noises.

8,000 each day.

6,200 times each

year.

Deep within the volcano it is so hot that some rocks

slowly melt and become a thick flowing substance (magma). Because magma is lighter than solid rock around it, it rises and collects in magma chambers

inside the volcano. Eventually some of the magma is forced up through cracks, fissures and holes in the ground and finds its way into the main vent of the

volcano.

When the magma is half way up the main vent it turns into lava. The heat of the lava (750°C) burns the

remaining rocks from the magma as it continues to get hotter and hotter while it is rising up the main vent. Once the lava reaches the crater of the volcano a

volcanic eruption occurs.

Dry Lava Fast

Lava

LavaPowerful

Lava

Sound of Lava

Stromb

Underwater Volcano

2sec

3sec

3sec

5sec

5sec

13sec

36sec

Pressure of the gas within the earth's crust can cause a volcano to erupt. An earthquake can also cause a volcanic eruption. This happens when the earths surface moves (an earthquake) and forces the magma to move up into the chambers of the volcano until it hits the main vent and explodes.

The ring of fire is an invisible ring that covers most of the pacific ocean. It shows where most volcanoes are.

The Richter Scale , assigns single number to quantify the amount of seismic energy releases by an earthquake. It is a base- 10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a Wood- Anderson torsion seismometer output.

Seismic energy: The energy released by a earthquake.

A scale of measurement that uses the logarithm(power) of a physical quantity instead of the quantity itself.

Amplitude: Greatness of magnitude.

Logarithmic scale: