VULCANICITY is a process through which molten rocks (magma) are intruded within the earth’s crust or extruded onto the earth’s surface.
Vulcanicity is aided by the process of faulting which forms cracks in the earth’s crust through which magma escapes.
Volcanicity on the other hand involves the expulsion of molten lava on the earth surface to form various features like caldera and crater
When magma is intruded within the earth’s crust, it cools down and solidifies to form intrusive volcanic features e.g. batholiths, sills, dykes, lopolith, and laccolith.
When magma is extruded onto the earth’s surface, it changes to lava leading to the formation of lava plateaus, calderas, craters, hot springs, fumaroles, and geysers
Economic importance of volcanicity
- Sills can lead to formation of waterfalls e.g. Karuma falls which are good sites for generation of hydro electric power. Water falls also attracts tourists due to beautiful scenery they create and thus creates employment to tour guides and enable the country to earn foreign exchange
- Volcanic Mountains help in the formation of relief rainfall on the wind ward side which supports agriculture. Areas which have volcanic mountains such as around Kilimanjaro region in Tanzania experience heavy rainfall which encourage the production of crops such as coffee and tea. This crops when sold help farmers increase they income and consequently their standard of living
- Hot springs provide medicinal water e.g. Kitagata hot spring water contains sulphur which is used to treat skin diseases. The medicinal effects of these springs attracts people from all over the world and consequently help the areas around the springs to get market for their products and increase their income
- Volcanicity leads to the formation of lakes which provide water for domestic and industrial use e.g. Lake Bunyonyi. Apart from provision of water the lakes formed due to volcanicity provide means of transport and are also a tourist attractions which help the country to earn foreign exchange
- Crater lakes are a source of minerals which can be sold for money e.g. salt obtained from Lake Katwe.
- Volcanicity favours mining because it exposes valuable minerals near the surface of the earth e.g. Diamond mining in Mwadui plug in Tanzania. The diamond and other minerals around the world which result from volcanicity has helped the host countries lift themselves from poverty for example Botswana have used it’s diamond to move from poor country to middle income economy
- Volcanic features attract tourists who bring in foreign exchange used for national development.
- Volcanic lava leads to production of fertile soil hence favouring agriculture e.g. coffee growing along the slopes of Mt. Elgon. When lava cool down and solidify and later being weathered and turned into the soil they become very fertile soil due to minerals contained in the lava
- It’s a basis for geographical studies hence improving on research and study purposes. When magma is extruded on the earth surface they are studied to understand the content of what is within the earth’s surface and that has expanded our knowledge on the structure of the earth