Flashcards
Geography- Tectonic plates
Cards in this deck (15)
- 1Topic 3: Tectonic landscapesTopic 3:
Tectonic Lnadscapes - 2Describe the distribution of earthquakes and volcanoes on a global scale.They are found in many different parts of the world. They tend to occur in narrow bands that are found in: the middle of oceans such as the Atlantic. Along the edges of continents, such as the west coast of America.
- 3What causes plate movements? Also explain how volcanoes form over hotspots?Tectonic plates move because of convection currents in the earths mantle. Some volcanoes occur in the middle of tectonic plates where the crust is thin and hot magma can escape.
- 4What are convergent plate boundaries and its characteristics?Convergent plate boundaries are where plates collide. 1)Plates move together and collide. 2)Very violent volcanoes and earthquakes occur. 3) Subduction zones form due to downward movement of the dense oceanic crust into the mantle, beneath the less dense continental crust. 4) Fold mountains can form when both plates are pushed upwards by the force of the collision.
- 5What are divergent plate boundaries and its characteristics?Divergent boundaries are where plates move apart. 1) Plates move apart. 2) Less violent volcanoes and earthquakes occur. 3) New sea floor is created at mid- ocean ridges as magma rises up through the ridge and solidifies.
- 6What are conservative plate boundaries and its characteristics?Conservative boundaries are where two plates slide past each other. 1) Plates slide past each other. 2) No crust is destroyed or created, therefore no volcanoes are formed. 3) Plates can 'stick'; this increases pressure which can be released as violent earthquakes.
- 7What is the richter scale?The richter scale measures the energy released during an earthquake. The magnitude increases IO fold as you move up the scale because it is a logarithmic scale. There is no upper limit to the scale. A seismometer is used.
- 8What is the mercalli scale?It measures the effects or impacts of the earthquake, the damage done and what people feel. The scale is measured in Roman numerals from I to XII.
- 9What is the 'focus' and the 'epicentre'?The focus is the central point of the earthquake deep under the surface, where the earthquake actually happens. The epicentre is the point on the surface directly above the focus.
- 10State the reasons why people continue to live in areas of volcanic and earthquake activity?Social: some people worship earthquakes, believing they are ancient spirits. Example:(Mt Merapi, Indonesia and Mt Fuji, Japan). Environmental: Area may attract tourists, bringing jobs and higher income. Example: (Mt Etna, Sicily). Economic: soils are often very fertile, with lots of farming opportunities. Example: (The volcanic soils of Colombia are used for coffee crops). Minerals like diamond, gold and tin are found in volcanic soils. Example: (Mt St Helens, USA).
Social: Earthquake- proofed buildings and disaster plans make people feel safer. Example: (San Francisco Cali, USA).
Environmental: Often areas of great beauty, where people like to live. Example: (Silicon Valley, Cali, USA). Economic: Popular tourist locations, with jobs and income opportunities. Example: (LA, Cali, USA). - 11What are the causes and effects of volcanic eruptions or an earthquake on people and the environment?Chances Peak is a volcano in the southern part of the island of Montaserrat. It became active in 1995 and erupted on 25 June 1997. The north american plate is subducted below the continental Caribbean plate, creating a trench. Oceanic crust melts due to high temperatures. Build up of pressure from plate movement causes earthquakes. Molten rock is forced up through fissures in the continental crust, and explodes violently in volcanic eruptions. 19 people were killed , 100- 150 homes were destroyed and also people's feet and car tyres were burnt by ash and also the Trants village was covered in 4km2 of ash. 7000 people were evacuated from the island and the danger zone. Also face masks were issued to children to prevent silicosis.
- 12Explain how the effects of volcanic eruptions and earthquakes are reduced through prevention?Barriers or ditches- made from concrete or rock are used to divert lava flow away from settlements, (Mt Etna). Water spraying- is used to cool down and solidify lava flow, (Mt Heimaey, Iceland). Land use planning- ensures that buildings are not built too high or close to a volcano. The emergency services- need to be equipped and trained to deal with hazards effectively. Earthquake proof buildings- using cross bracing counter- weights, ball bearings and rubber foundations help stabilize buildings, (San Francisco).
- 13Explain how the effects of volcanic eruptions and earthquakes are reduced through predicting?1) Tiltmeters and lasers- measure the change in the slope of the land (San Andres Fault, Cali).
2) Seismometers- measure the seismic waves produced from an earthquake, (Chances Peak).
3) Gps and satellite images- monitor the bulging of volcanoes and changes in ground heat, (Mt St Helens, 1980). - 14Challenges for the PlanetChallenges for the Planet
- 15How and why has climate changed since the last ice age?1) Orbital geometry- (The way the Earth orbits the sun) Circular orbits results in cold, glacial periods. Elliptical orbits results in warmer periods.
2) Volcanic eruptions- Mt Laki in 1783 released so much ash that it blocked the sun.
3) Solar eruptions- The amount of energy given off by the sun.
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- Flashcards on Geography- Tectonic plates, created by Jake Turner Retros on 07/02/2016.
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- Jake Turner Retros
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