Chapter 1 Flashcards
Name the 3 layers of the earths structure
The crust, the mantle, the core
Describe the crust
The crust is the outer layer. It is made up of solid rock. The oceans and continents lie on top of the crust
Describe the middle layer of the earths structure
The mantle lies under the crust. It is made of molten rock called magma
Describe the most inner layer of the earth’s structure
The core is the centre of the earth. It is made of iron and nickel. It is the hottest part of the earth at 6,000 degrees. The core can be divided into the inner core and the outer core
Describe what plates are
The earths crust is broken into pieces called plates. The plates with land on top are called continental plates and the plates with oceans on top are called oceanic plates. The line where two plates meet is called a plate boundary
Describe convection currents
When magma is heated in the mantle it rises towards the crust. As it rises it cools and moves sideways. This causes friction between the magma and the crust and pulls the plates. The magma cools and sinks back down into the mantle. This process is constantly repeated.
What is plate tectonics
The study of plates and their movements is called plate tectonics
What boundaries do plates the collide have
Plates that collide with each other have a destructive/or convergent boundaries. Here crust is destroyed
What boundaries do plates the collide have
Plates that collide with each other have a destructive/or convergent boundaries. Here crust is destroyed
What happens when two plates collide
Huge pressure is built up and the heavier plate is pushed under the lighter plate. This is called subduction. The heavier plate melts back into the mantle. The lighter plate is lifted up forming fold mountains. Plates the collide also cause earthquakes and volcanoes. Eg the Andes
What happens when plates separated from each other
Plates that separate from each other have constructive boundaries. Here crust is created. Plates that separate form volcanic mountains, volcanic islands and mid ocean ridges. Eg Iceland is a volcanic island
Whaere does most volcanic activity occur
The pacific ring of fire
What is a mid ocean ridge
Hot molten rock, known as magma, rises up from the mantle through the cracks in the crust. The magma then cools, hardens and builds up, forming a ridge of rock. Eg. In the middle of the Atlantic Ocean the American plates are separating from the Eurasian and African plates and the magma that rises up through the cracks there is creating a chain of mountains on the sea bed known as the mid Atlantic ridge
Tell me about volcanic islands
Mountains on the seabed, formed when magma wells up through the cracks into the crust sometimes rise above the surface of the ocean. These mountains are called volcanic islands. Eg Iceland
Explain what happens during a volcanic eruption
Magma rises up from a magma chamber in the earths crust through a vent. A vent is a narrow tube in the crust. When magma reaches the surface we call it lava. Lava,hot ash and rocks are thrown into the air as the volcano erupts and an ash cloud is formed. There is a build up or material around the vent. As more eruptions occur,layer is added to layer until a cone-shaped mountain is formed . The lava continues to flow from a creator at the top of the volcano. Eg Mount St Helens
Name the 3 types of volcanoes
Active, dormant and extinct
Give me an example of an active volcano
Mount etna
Give me an example of a dormant volcano
Mount Vesuvius Italy
Give me an example of an extinct volcano
Croghan Hill in Co.Offaly
What are 3 socio-economic effects of volcanoes
The soils made from lava are rich in minerals and so are very suitable for agriculture, tourist visit sites of some famous volcanoes such as Mount Etna and Sicily Italy, water heated underground by volcanic activity can be used to generate geothermal energy to heat peoples homes
Describe 3 negative socio-economic effects of volcanoes
Gases produced by volcanoes such as sulfur dioxide can poison people who live nearby and cause acid rain this can affect economic activities such as agriculture fishing and forestry, a lava flow burns everything in its path. There can be huge loss of human life when a volcano erupts, when volcanic material with mixes water from rivers or rain or melting snow and ice a river of mud called lahar can be created.
Tell me about geothermal energy in Iceland
Geothermal energy is energy produced from the heat of the earth
• The steam from the hot water is used to create electricity, which provides power for factories, offices and houses.
• Water heated by geothermal energy is piped into offices, schools and people’s homes and used to heat them.
• It is one of the cheapest and most sustainable forms of energy.
Tell me about tourism in Iceland
Tourism has positive and negative socio-economic effects:
• Tourism provides many job opportunities. For example, locals work as tour guides and lifeguards.
• Tourism can lead to soil erosion and increasing property prices.
What were the short term responses to the eruption of Mount St Helens
• The volcano was monitored before the eruption. This meant that authorities were able to evacuate the areas surrounding Mount St Helens. The death toll of 61 would have been much higher it the area had not been evacuated.
• A million tonnes of ash took ten weeks and millions of dollars to remove. It also provided jobs for 200,000 people.
• Electricity was restored.
What were the long tear responses to the eruption of Mount St Helens
Millions of trees were replanted. These trees will not be fully grown until 2050.
• Farmers were given money as compensation for their losses.
• The government gave money to rebuild damaged buildings and transport routes.
• Tourist facilities were built to accommodate the people who came to visit the area.
