These flows occur when the vent area or ash column collapses. Pyroclastic flows - These are high speed avalanches of hot ash, rock fragments and gas which move down the sides of a volcano. Lava flows - These are streams of molten rock. These gases are mainly steam, carbon dioxide and compounds of sulphur and chlorine. Volcanic gases - All magma contains dissolved gases that are release during and between eruptions. You need to learn the definitions of the terms volcanic gases lava flows pyroclastic flows tephra. A number of these effects are shown on the diagram below., Can you categorise them into primary and secondary effects? You need to be able to describe at least 3 primary and 3 secondary effects of volcanic eruptions. The primary effects are immediate and come from the eruption itself whereas the secondary effects result from the primary effects. The effects of volcanic eruptions can be divided into primary and secondary effects. The diagram below shows how much bigger shield volcanoes are than composite volcanoes. Basic lava is runny so it flows quite a long way before it cools. You get these types of volcanoes along constructive plate margins and also where there are hotspots. Shield volcanoes form when the lava is basic (the opposite to acidic). They produce lots of lava but they tend not to erupt violently. Shield volcanoes are enormous features built up only from layers of lava. This kind of volcano is found at destructive plate margins. Alternate layers are formed because each eruption first produces rock fragments which are later covered by lava. The sticky acidic lava pours slowly down the side of the cone and cools quickly to produce a steep sided volcano. It also introduces some of the hazards of volcanoes as well as briefly discussing some of the benefits that they bring to an area.Ĭomposite volcanoes happen where the lava is acidic. THe second video (the one on the right) is much more useful as it highlights some of the key differences between composite and shield volcanoes. The first video (the one on the left) is a catchy song that tells you the basics about an eruption. You need to know about two different types of volcano - composite volcanoes and shield (basic) volcanoes. Volcanoes can be active (erupting), dormant (sleeping) or extinct (no eruption for 10,000 years and unlikely to erupt again). Magma which reaches the earth's surface is called lava. ![]() to be able to describe at least 3 secondary effects of a volcanic eruptionĪ volcano is an opening in the ground where magma forces its way to the surface. to be able to describe at least 3 primary effects of a volcanic eruption to be able to describe at least 3 differences between composite and shield (basic) volcanoes
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |