Volcanoes Flashcards
Name four primary volcanic hazards
Lava flows, pyroclastic flows, tephra and ash fall and gas eruptions
Describe lava flows
A stream of lava as hot as 1170C and may take years to cool completely but are too slow to be a threat e.g. Kilauea, Hawaii 2014
Describe pyroclastic flows
Mixture of dense hot rock, lava, ash and gases, they’re very dangerous as they move very quickly at approx. 100km/hr at temperatures of 700C e.g. Mount Sinabong, Sumatra 2015
Describe tephra and ash fall
Volcanic rock and ash, tephra can cause injury and death and the ash causes poor visibility, slippery roads, collapsing roofs and faulty engines up to kilometres away from the volcano e.g. Eyjafijallajokul, Iceland 2010
Describe gas eruptions
Magma contains dissolved gases including sulphur dioxide which cause pollution up to thousands of kilometres away from the eruption e.g. Mount Pinatubo, Philippines 1991
Name two secondary volcanic hazards
Lahars and Jokulhlaup
Describe lahars
Mud, water and rock travelling down the side of the volcano
Describe jokulhlaup
Heavy and sudden floods formed by volcanoes melting glaciers so they may carry rock, gravel, ice and debris risking both lives and infrastructure e.g. Grimsvotn, Iceland 1934
Give three key facts of the 2010 Iceland volcanic eruption
- 2.5km wide
- 11,000m ash plume
- 700 people evacuated
Give two social impacts of the 2010 Iceland volcanic eruption
- Flights cancelled for a week
- 10 million passengers stranded
Give five economic impacts of the 2010 Iceland volcanic eruption
- Global airlines lost $1.7bn in revenue
- European economy lost $5bn
- Kenya lost $1.3bn a day in revenue
- Increased Icelandic tourism
- 30% of global airline capacity cut (75% of European airline capacity)
Give three environmental impacts of the 2010 Iceland volcanic eruption
- Rivers rose by 80cm
- Ash madeland fertile
- 20 farms destroyed
What was the vulnerability of Iceland for the 2010 eruption?
30 minute warning system so no one died
Give three key facts of the 2002 volcanic eruption in Nyiragongo, DRC
- 3470m high
- Stratovolcano
- Erupted 34 times since 1882
Give five social impacts of the 2002 DRC volcanic eruption
- 147 people died from CO2 suffocation
- 120k homeless
- 400k evacuated
- 2 out of 4 hospital buried in 2m of lava
- Looting of empty homes
Give three economic impacts of the 2002 DRC volcanic eruption
- Lava covered Goma airport
- 80% of commercial infrastructure destroyed
- 4,500 buildings destroyed
Give one environmental impact of the 2002 DRC volcanic eruptions
High sulphur and methane emissions
Why was the DRC so vulnerable?
- Early tremours not acted on
- No where to go as Niriwanda couldn’t cope with refugees
- Due to political status MEDCs reluctant to provide aid
Describe the temperature of each type of lava
Basaltic - 1000-1200C
Andesitic - 800-1000C
Rhyolitic - 650-800C
Describe the main minerals of basaltic lava
50% silica
water, gas and aluminium
High CO2, iron and magnesium
Describe the main minerals of andesitic lava
60% silica
High water and hydrochloric acid
Low SO2
Describe the main minerals of rhyolitic lava
70% silica
Potassium, sodium and aluminium
Low iron and magnesium
What is the gas content of each types of lava
B - 0.5-2%
A - 3-4%
R - 4-6%
How are each type of lava formed?
B - melting of mantle minerals
A - subducted oceanic plate melts and mixes with seawater, lithospheric mantle and continental rocks
R - melting of lithospheric mantle and slabs of previously subducted plates
