Risks and benefits

NAME/INDEX NO.		CLASS	307	DATE
SUBJECT	Geography	TITLE	PDEE:Risks & Benefits of Volcanoes

Risks of living near a volcano

Point	Describe	Elaboration	Example
Destruction by volcanic materials	Volcanic materials such as lava, volcanic bombs and rock fragments impose a risk on the people living in volcanic areas.	People who live in volcanic areas are faced with eruptions that produce lava and rock fragments. These volcanic materials can lead to a widespread damage of property. The lava with high temperatures of between 500° C and 1400° C burns the areas it flows through.	For example, the ongoing eruption of Kilauea in Hawaii since 1983 has destroyed many homes and highways.
Landslides	Landslides can occur due to the structural collapse of a volcanic cone during an eruption.	Landslides may have few rock fragments or several hundreds of cubic kilometres. They may obstruct the flow of rivers causing floods, blocked roads and buried villages and farmlands.	The eruption of Nevado del Ruiz in the Andes mountains in 1985 released a pyroclastic flow. The lahar engulfed the town of Armero and killed more than 20,000 people.
Pollution	Ash particles ejected during an eruption can disrupt human activities.	Thick plumes of ash may eventually settle on the ground and block sunlight, suffocate crops, and cause severe respiratory problems for animals and people.	During AD 79, Mt. Vesuvius (Italy) erupted and expelled a deadly cloud of volcanic gas, stones, ash and fumes that rose to a tremendous height of 33km.
Effects on weather	Gases such as carbon dioxide, Sulphur dioxide, hydrogen and carbon monoxide are released which may have an impact on the weather.	Sulphur dioxide released from volcanic eruptions has impacts on the environment. It may react with water vapour and other chemicals in the atmosphere to form sulphur-based particles. These particles reflect the sun’s energy back into space and temporarily cool the earth for periods of time.	The volcanic eruption in Iceland in 2010 produced extensive volcanic ash clouds made up of abrasive glass, sand and rock. These particles posed a serious danger to aircraft and resulted in closure of air space over much of Europe.

Benefits of living near a volcano

Point	Describe	Elaboration	Example
Fertile volcanic soils	Volcanic areas has fertile volcanic soils that is due to lava and ash from the eruptions. The volcanic soils are good for farming.	Lava and ash from volcanic eruptions break down to form fertile volcanic soils. Despite continuous use, the soils are more fertile than most non-volcanic areas of Indonesia.	The volcanic soils of Java and Bali in Indonesia support the growing of crops like rice, tea and coffee.
Precious stones and materials	Volcanic rocks can be rich in precious stones and minerals.	After millions of years, precious stones and minerals can be extracted from volcanic areas when the upper layers of rocks have eroded.	The old volcanic rocks at Kimberly in South Africa are one of the world’s richest sources of diamond.
Tourism	Volcanic areas offer a variety of activities for tourists to engage in.	People visit volcanoes to hike or camp in the area, or simply to enjoy the scenery. Volcanic areas are rich in history and people can visit these areas to learn more about them.	The ruins of Pompeii, Italy is a popular tourist spot. When Mount Vesuvius erupted in 79 CE, the roman town was buried by layers of ash and uncovered over the years.
Geothermal energy	Geothermal energy is derived from the heat in the earth’s crust.	When groundwater comes into contact with hot rocks beneath the surface, it heats up and erupts as hot water or steam. The hot water or steam can be harnessed to drive turbines and produce electricity,	70% of Iceland’s electricity is generated from geothermal power because of the large numbers of volcanoes in the country.