Impacts of volcanic activityKey knowledge: examine the impact of change on

natural environments and human activity.

$

Benefits for human activities

Fertile soil: Volcanic soils break down to produce some of the most fertile soil on Earth, rich in iron and magnesium. Greater crop production leads to higher population densities in volcanic areas. Places such as the African Rift Valley, Mt Elgon in Uganda, and the slopes of Vesuvius in Italy all have productive soils thanks to the breaking down of volcanic rocks and ash

Benefits for human activities

High Biodiversity : volcanic regions generally have a greater biodiversity than non-volcanic regions. The higher the altitude of many volcanoes also produces orographic rainfall. As a result, natural vegetation and crop grow quickly and support a wide variety of animal species.

Orographic rainfall is rainfall produced by condensation around mountains.

Biodiversity is the variety of living things

Benefits for human activities

Mineral deposits: most valuable metallic mineral ores mined in the world are associated with past volcanic processes. Minerals such as gold, silver, copper, lead and zinc are concentrated by tectonic activity.

Benefits for human activities

Fossil fuels: coal, oil and natural gas are produced in geologic basins formed by plate tectonic processes.

Benefits for human activities

Geothermal energy: steam from active volcanic regions and underground rocks can be used to generate electricity and supply hot water and heating needs. More than 70% of Iceland’s homes are heated with geothermal energy.

The main form of geothermal power is where bodies of water, either above or below the earth's surface, are converted to steam by the earth's heat. The steam is collected, and used to power a turbogenerator just like in a regular coal fired power station.

The other form is called hot rock geothermal energy. It is where water is pumped below the surface to areas of hot rock. The water turns to steam, and is brought back to the surface to drive a turbogenerator.

Benefits for human activities

Tourism: Volcanic sites can also be very effective tourist attractions. Even the less active ones that are just puffing out steam and smoke are impressive sights and attract tourists from around the world. Warm bathing lakes, hot springs, bubbling mud pools and steam vents are often present around volcanoes, drawing in tourists.

The affect of volcanic gases on global temperature

Sulphur from eruption mixes with water vapour in atmosphere.

Sulphuric acid clouds form.

Acid droplets absorb incoming solar radiation and are reflected back into space.

Global temperature drops.

Reading found on pages 49-50

Questions to be completed from page 51