Chapter 2-volcanoes Flashcards
What is a composite volcano?
Tall come with a narrow base and steep sides
Made of ash and alternate layers of lava and ash
Irregular with long dormant periods
Violent explosions-steam, ash, lava, rock
Lava is sticky and doesn’t flow so far
At what plate do composite volcanoes occur at?
Destructive plate margin
At what plate do shield volcanoes occur at?
constructive plate margins
What is meant by primary effects of a volcano?
The immediate effects of the eruption caused directly by it
What is meant by the secondary effects of volcanoes?
The after effects that occur as an indirect effect of the eruption on a longer time scale
What is meant by the term aid?
Money, food, training and technology given by richer countries to poorer countries, either to help with an emergency or to encourage long term development
Eyjafallaiokull volcano case study- what were the secondary effects?
Economic
London lost £102 million of tourist income
Hotel owners suffered, insurance companies
Vegetables and flowers ruined in Africa
Fruit and veg stopped for the U.K
Cost of airline industry
Eyjafyllaiokull-the case study- the secondary effects
Environmental
Some rivers were still blocked after 1 year
105m thick ice caps melted
Respiratory problems for animals
Eyjafallaiokull- case study- the primary effects
Environmental
No loss of life-preparation
Major floods to Icelands
Fine ash sifting up rivers-harbours closed
20 farms destroyed
Eyjafallaiokull- case study- social primary effects
Social
Ash cloud disrupted many peoples holidays and jobs
6 days of no flying-95,000 cancelled
Ash damage to homes
7 million people stranded worldwide
Eyjafallaiokull-the case study- the secondary effects
Social
World health organisation warm people to stay inside
Destroyed parts of main route 1 road
What are the Characteristics of a super volcano?
Ejects over 1000km3 of material
Lies dormant for 1000’s of years
Formed in a caldera
Extensive Magma chamber
What is a shield volcano?
A cone with a wide base and gentle slopes Made of lava only Regular frequent eruptions Little violence with lava Lava is runny and flows a long way
How does a super volcano occur?
Magma chamber is fed with magma from mantle over hotspots and weak areas of the earths crust
Growing magma chamber forces ground up into a dome
Gas and ash escape through fissures and into cracks in the surface casing a super eruption
What happens after a supervolcano?
What is left?
The land collapses into the new magma chamber creating a depression calf a caldera.
What are the long term effects of a super volcano?
Crops won’t grow
Global climate change
40% of global population Could face starvation
Economies would collapse
What are the immediate effects of a supervolcano?
1 in 3 people affected would die
Temperatures would fall by 12-15 degrees
Kill 87,000
How do volcanoes form?
They form when magma escapes through a vent
They also form hotspots
Yellowstone- case study- super volcano
When did it last erupt?
Three huge eruptions have happened in the last 3 million years. the last eruption was 630,000 years ago, and was 1,000 times bigger than the Mount St Helens erruption
Yellowstone- case study- supervolcano
How big is the caldera?
The caldera is 55 km by 80 km wide. The next eruption is predicted to have catastrophic worldwide effects.
Yellowstone- case study- super volcanoes
Why was the volcano formed?
The supervolcano at Yellowstone is formed because of a volcanic hotspot
Yellowstone- case study -super volcano
Why are people attracted to it? And how many people go a year?
Every year millions of visitors come to see the related features, such as geysers and hot springs. Old Faithful is one example of a geyser.
How are volcanos monitored and predicted?
Earthquakes are a frequent sign of an eruption and their frequency and strength can be recorded
Bulges appear
Increased amount of sulphur dioxide
Seismograms
Yellowstone- the case study- super volcano
What would be the effects of the eruption?
10,000km4 of land destroyed
Kill 87,000 people
15cm of ash would cover buildings within 1,000km
1 in 3 people effected would die
