The Restless Earth Flashcards
(32 cards)
How are fold mountains formed?
Collision at destructive plate boundaries
2 continental plates squash the oceanic crust in between causing the sedimentary rock to rise
Himalayas
Give an example of a fold mountain Where is the location? How and when did it form? What is the tallest peak? What is the population?
THE ALPS
It was formed around 30 million years ago by a collision between African and European plates
Tallest peak is Mont Blanc
Population= 12 million
How do people use the Alps for farming?
The steep sided upland areas aren’t very good for growing crops, as a result they are used for farming goats to provide milk, cheese, and meat
Some of the Sunnier slopes have been terraced is vineyards (lavaux in Switzerland)
How are the catered for tourism?
100 million tourists visit the Alps ever year making tourism a huge part of the economy
70% of the tourists visit the snow-covered mountains in the winter for skiing snowboarding and ice climbing in the summer tourist visit walking mountain biking paragliding and climbing
New new villages have been built to cater for the tourism in such as Tignes in France
Ski runs skilifts and holiday chalets and restaurants all pepper the landscape
How is hydroelectric power used in the Alps
The narrow valleys in the Alps are dammed to generate HEP
e.g. Berne in Switzerlnd
Switzerland gets 60% of its electricity for HEP
The electricity is used to power local businesses and homes but also exported to other towns/villages
How do people use the apps for mining?
Salt, iron ore, silver, copper and gold are all mined.
However the rate of mining in the Alps has dramatically decreased due to cheaper foreign sources
How is the Alps used for forestry?
Scots pine is planted all over the Alps as it is more resilient to the munching goats which kill the sapling.
Trees are logged and sold for furniture
How of people adapted to conditions in the Alps?
Steep relief: Goats are farmed as they are well adapted to live on steep mountains. Trees and man-made defences are used to protect against avalanches and rock slides
Poor Soils: animals are grazed in highland areas as the soil isn’t very good for growing crops
Limited Communications: roads have been at lower points between mountains such as the Brenner Pass between Austria and Italy. However they may become blocked by the snow, making transportation very slow. As a result tunnels are cut through mountains such as Lötschberg cutting through the Bernese Alps in Switzerland
Give an example of a composite volcano and a shield volcano
Composite- Mt. St Helens 18th May 1980
Shield- Mauna Loa (Hawaiian Islands)
How do scientists try and predict volcanoes?
Tiny earthquakes
Escaping gas
Shape
What is an example of a case study for a volcano?
When did it erupt?
What caused it to erupt?
Mt St Helens
Erupted due the the Juan de Fuca plate subducting under the North American plate (destructive plate margin). This cause a build up of heat and pressure which created vents in the North American plate allowing lava to escape i the surface.
The volcano was also triggered by an earthquake measuring 5 on the Richter scale beneath Mt St Helens- 18th May 1980 @ 8:32am. The North East side of the volcano became unstable and collapsed as an Avalanche, then creating pyroclastic flow of lava and ash.
What were the primary effects of the Mt St Helens eruption?
- 57 deaths
- Every tree up to a radius of 25km was destroyed
- Destroyed 250 homes
- Ash fell creating a layer of 15cm causing traffic and airline schedules to be cancelled
What were the secondary effects of the Mt St Helens eruption?
- Ash fell into rivers destroying animal life as the temperature of water increased
- Ash forced people to wear masks within a 120km radius
What were the immediate responses of the Mt St Helens eruption?
- Helicopters were used in the search for survivors
- 2 million masks were sent out to zones cautioned with ash
- Ash covering roads was cleared within 3 days
What were the long term responses of the Mt St Helens eruption?
- Houses continued to be rebuilt until 1990
- Millions of tree were replanted due to the serve loss of timber, costing around $300 million
How does a supervolcano form?
Give an example
The magma rises up through cracks in the crust, forming a large magma basin. The pressure causes a bulge to form on the surface which is several km wide. The bulge eventually cracks letting the lava through, the eruptions cause earthquakes and fumes of ash and rock to be released. As the magma basin empties, the bulge is no longer supported and so it collapses. When the eruption is finished a caldera is formed, where the bulge collapsed, this sometimes fills with rainwater to form a lake. e.g Lake Toba in Indonesia
Supervolcano= Yellowstone national park USA
They can also form at destructive plate margins
What are the global consequences of a supervolcanic eruption?
An eruption will throw out thousands of cubic meters of lava ash and rock.
A thick cloud of super heated gas will flow and destroy everything within tens of miles from the volcano
Ash will shoot kilometres into the air and block out almost all daylight over continents
The ash would settle over hundreds of square kilometres covering buildings and fields.
87,000 could be killed
What does the Richter scale measure? What device is used to measure the vibrations of an earthquake? What is meant by logarithmic? What does the Mercalli scale measure? How is it measured? What is the scale?
The amount of energy released from an earthquake scale:1-9+
Seismometer
Each stage is 10x more powerful
It measures the effects of the earthquake
By recording observations from eye witnesses or photos
Scale: 1-12
How large is the size of the magma chamber under Yellowstone?
80km long
40km wide
8km deep
Name an example of an earthquake in an MEDC?
When did it occur?
What caused it?
Kobe, Japan 1995-
17th January 5:46am, measuring 6.9 on the Richter scale.
Destructive plate margin
2 oceanic plates- Pacific and Philippine plates subduct under the Eurasian plate
What were the effects of the Kobe Earthquake in Japan?
More than 102,000 buildings were destroyed
Motar ways collapsed
Bullet train route was severely damaged
The estimated cost to restore the damage was £100 billion
What are the initial responses to the Kobe earthquake
Locals dug through the rubble to help survivors
The government were criticised for not rescuing people quick enough and refusing offers of aid from other countries
What are the long term responses of the kobe, Japan earthquake?
Water, gas, telephone services were fully function able by July 1995
Railways were back in service by August 1995
Most of the buildings and roads constructed in the last 20 years are designed to be earthquake proof
LEDC earthquake case study- Hati
When was it?
What caused it?
12th January 2010
The capital: Port Au Prince was 10 miles south west from the epicentre
Earthquake measured 7 magnitude on the Richter scale.
Caused by the North American plates sliding past the Caribbean plate in a conservative plate margin.
