Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
9 Cards in this Set
- Front
- Back
|
Where are volcanoes usually found? |
Plate boundaries
|
|
|
Describe a composite volcano. |
-steep slopes and a narrow base -layers of thick lava and ash -eruptions infrequent but often violent -destructive plate boundary -acid lava |
|
|
Describe a shield volcano. |
-low rounded peak -wide base and gentle slopes -frequent but non violent eruptions -basic lava -constructive plate boundaries
|
|
|
Describe the Soufriere Hills Volcano 1995, Mont Serrat. The Primary Effects The Secondary Effects
|
Volcano was dormant for many years - wasn't considered dangerous. Volcano was caused by the carribbean plate being subducted under the North American plate. The subduction of the Carribbean plate produced acid lava which works its way up through the crust - erupt violently and infrequently. Eruption started in 1995-1997. Threw out ash, lava and gas. THE PRIMARY EFFECTS -killed 23 people -ash covered 75% of island - destroying farms and villages and the capital, Plymouth, had to be abandoned. -5000 people became refugees in the North of the Island. -5000 people evacuated to other islands
The Secondary Effects -Economy of the island was destroyed. -unable to farm due to ash. -factories in Plymouth were destroyed -tourism industry destroyed -port and airport closed which made imports challenging -Britain sent £41 million to redevelop the North of the Island -£10.5 million to help with refugees -by 2005 a new airport and capital had been made
|
|
|
Describe the Eruption of Nyiragongo, Congo 2002
|
Volcano in East Central Africa in Congo. Caused by African plate starting to split apart. As it pulls apart the land between the cracks in the Earths crust slip downwards to make the East African rift valley. At the same time magma rises up fro, the mantle to form basic lava. PRIMARY EFFECTS -Lava spilled southwards (60kph) and flowed across Goma airports runway -flowed through the town and split it in half -destroyed many homes, water pipes and roads -set of explosions in fuel stores and power plants -45 killed
Secondary Effects -50,000 people fled to Rwanda where the spent the night sleeping on streets of Gisery, where there was no shelter, electricity or clean water.) -risk of cholera -water had to be supplied in tankers -aid agencies distributed food, medicine and blankets -looting took place in Goma |
|
|
The Eruption of Mt St Helens in 1980 |
Juan de Fuca plate being subducted by the North American plate. As the Juan de Fuca plate melts, it produces acid magma which turns to acid lava. PRIMARY EFFECTS -Massive eruption - totally blew the top of the mountain off. -This triggered a deadly cloud of hot ash and gas, this went down the mountainside, destroying trees, killing wildlife and 57 people. -Just before eruption, earthquake caused a landslide and that, combined with ash and trees blocked rivers and roads. -Very fine ash got into air con systems in houses and blocked them. LONG TERM EFFECTS -roads and bridges had to be re-built -fallen trees had to be removed from both land and rivers -new forests re-planted
|
|
|
Why do people live near volcanoes? |
-volcanic rock makes very fertile soil -a tourist attraction and can make money -minerals can be found in volcanoes and mined (Sulphur, borax) -hot springs - hot water can be piped for central heating system
|
|
|
What is a super volcanoes?
|
A super volcano throws out vast quantities of materials. They're so big they can alter the landscape for miles around and cause a volcanic winter (where so much ash - sun blocked out and temp drops) |
|
|
Yellowstone - a super volcano |
-there's evidence to say that magma beneath yellowstone is shifting -signs of increasing activity at Norris -ground has risen 70cm in places -magma chamber beneath yellowstone is thought to be 80km long, 40km wide and 8km deep -eruptions have occurred here 2 million years ago, 1.3 million years ago and 630,000 years ago -an eruption is likely to destroy 10,000km2 of land, kill 87000 people, 15cm of ash woukd cover buildings within 1000km and 1 in 3 would die
|
