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 M L 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 to to to 4.9 Micro 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 Lava Powerful Lava Sound of Lava Stromb Underwater Volcano 2sec 3sec 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.