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37 Cards in this Set
- Front
- Back
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3 Types of Plate Boundaries |
Destructive Constructive Conservative |
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Slap pull |
Theory that the earth's plates are moved through gravitational sliding |
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Destructive plate Margin |
Oceanic moves towards a continental plate. Denser oceanic plate is subducted down and destroyed. The pressure at the margin therefore increases which can result in violent earthquakes and volcanoes |
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Constructive |
Earth's crust is forced apart the magma rises and solidifies to form a mid ocean ridge. This can result in volcanoes and earthquakes |
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Conservative plate margins |
Two plates sliding past each other slowly. Often they get stuck and pressure builds up and when the pressure is released it causes severe earthquakes but not volcanoes |
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Example of a conservative plate boundary |
San Andreas Fault |
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Example of a destructive plate Margin |
Nazca plate and South American plate boundary |
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Example of a constructive plate margin |
Mid Atlantic Ridge |
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Intra Plate earthquakes |
Can happen near the middle of plates. Associated with ancient faults and solid crust cracking over millions of years |
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Volcanic hotspots |
Continuous volcanic activity near middle of plates due to upwelling of magna from the Core such as hawaii |
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Mantle Plume |
Stationary upwelling if abnormally Holbrook within the earth's mantle |
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8 reasons why tectonic events have varied consequences - know at least half |
Level of development of country Magnitude or explosivity Preparation Speed of response Time of day or year Secondary Hazards Good governance Past experiences |
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5 pieces of evidence for continental drift |
Paleontology - fossils Paleomagnstism - plate movement Climatic evidence - glaciation found in non glacial areas Geography - Jigsaw fit Geology - Rocks with similar characteristics in different continents |
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Tethys sea |
Not quite sure |
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Basaltic lava |
Highest temperature Hot runny lava Not very explosive |
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Andesitic lava |
In the middle between the other 2 Sticky, considerable time between eruptions Can be very explosive |
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Rhyolitic Magma |
Low temperature high gas content Erupt rarely Can be devastating |
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3 Types of Magma |
Basaltic Andesitic Rhyolitic |
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What happens to silicon content in magma as they become more explosive |
Highest silicon rhyolitic Lowest silicon basaltic |
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Richter scale |
Original scale from 1 - 12 used to measure Magnitude of earthquakes |
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Benioff Zone |
Active seismic zone on a subduction plate. Hotspot for seismic activity at an angle of about 33 to 60 degrees on the subduction zone |
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Primary and Secondary waves |
Primary Waves arrive first, faster can move through rock and fluids, push pull waves Secondary Waves are slower than primary waves and can only pass through rock not liquids. Up down movement |
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Rayleigh and Love waves |
Rayleigh waves only travel through the surface of the crust moving rhe ground side to side felt by people Love Waves, also only travel through the surface fastest surface wave do the most damage to buildings. |
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Types of tectonic stress |
Tensional - Constructive Compressional - Destructive Shear - Conservative |
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Secondary Hazards caused by earthquakes |
Tsunamis (Boxing Day 2004) Liquefaction (Christchurch 2011) Landslides (kashmir 2005) |
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Liquefaction |
Ground made of fluids or soft rocks becomes liquidised and buildings built immediately collapse into it |
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What factors determine eruption type |
Crystal Content Gas content Temperature of Magma |
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How does crystal Content impact eruption style |
Crystals in magma make it more viscous and is more likely to explode than flow |
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Why does gas content impact eruption style |
Gases create explosions if they can't escape from viscous magma whilst being released without explosions from fluid magma |
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How does temperature impact eruption style |
High temperature magmas Erupt effusively whilst low temperature magma can't flow easily and is therefore more likely to explode |
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Primary hazards of a volcanic eruption |
Lava Flows (Hawaii) Pyroclastic Flows (Montserrat) Ash Fall (Ejyfajokull) Gas eruptions (St Helens) |
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Secondary Hazards of volcanoes |
Lahars (Pinatubo) Jokulhlaups (Ejyfajokull) |
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Hazard Risk formula |
Hazard X Vulnerability / Capacity to cope |
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What is risk |
Probability of harm or loss with death, injuries building destruction etc |
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Examples of Vulnerability |
Location of settlement Knowledge Ability to react Resilience and Preparation |
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6 factors hazard profiling |
Magnitude Speed of Onset Duration Areal extent Spatial Predictability Frequency |
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Ways in which Vulnerability increases |
Lack of mobile phone service Poverty Limited safe zones Weak governance Lack of sanitation or healthcare |
