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Geography - Ch2 1Y
Question | Answer |
---|---|
What are the plate boundaries that cause earthquakes? | Destructive and passive |
What is the outer most layer of the earth? | The crust |
What temperature is the inner core? | Approx. 6,000 degrees Celsius |
What temperature is the mantle? | Approx. 3,000 degrees Celsius |
What is the mantle made up of? | Semi molten rock called magma |
What is the core made up of? | Nickel & iron |
What is the crust made up of? | Solid rock |
What causes the plates to move? | Convection currents |
Explain how convection currents happen | The magma from the mantle rise and as it rises, it cools again and sinks back down. This process makes the plates move. |
What is the name of what the earths crust is broken up into? | Plates |
What is the name of the movement of continents over time? | The continental drift |
What landforms come from a constructive plate boundary? | Mid-ocean ridges Volcanic mountains Volcanic islands |
What landforms are created at destructive plate boundaries | Volcanic mountains Fold mountains |
At what plate boundaries do volcanoes happen? | Constructive and destructive |
What is the hole at the top of a volcano called? | The crater |
What is the area where all the magma is stored underneath the volcano called? | The magma chamber |
How are volcanic cones made? | From a build up of lava that has forced its way to the surface |
Name some good things about volcanic eruptions | (a) lava is very rich in minerals for soil (b) volcanoes can produce geothermal energy because of the heat they give off. |
Name some negative things about volcanoes | (a) the gases produced by volcanoes (like sulphur dioxide) can poison people. Acid rain. (b) lava destroys everything in its path (c) they can turn into things called lahars, which happens when the lava mixes with rain. It’s like a mud slide. |
What is a mid-ocean ridge? | A chain of underwater volcanoes found along the sea floor |
What plate boundary are mid-ocean ridges created at? | Constructive |
How do mid-ocean ridges form? | Convection currents move the plates and as they move, magma wells up to fill the gap. As the magma reaches the sea floor, it solidifies to form solid rock and over time this rock can build up to form a new ridge of land called a mid-ocean ridge |
Give an example of a mid-ocean ridge | Mid-Atlantic ridge (Eurasian and North American plates separate) |
What are earthquakes? | Sudden tremors in the crust |
What is a fault line? | A crack in the earth |
How do earthquakes happen? | Pressure builds up along the fault line. The sudden release of that pressure creates an earthquake |
Give an example of a fault line | The San Andreas fault line |
What is the focus? | The point below the surface where the earthquake starts |
What is the epicentre? | The point on the surface directly above the focus. This is where the tremors are strongest |
What are aftershocks? | Tremors that follow after the main earthquake |
What is a tremor? | A seismic waves or vibration that radiates from the focus |
Who is a seismologist? | Someone who measures earthquakes |
What is a seismograph? | Measures the magnitude of an earthquake |
What is the Richter scale | The unit seismologists use to measure earthquakes |
What is the highest an earthquake ever got in the Richter scale? | 9.5 - Chile in 1960 |
What is a primary effect of an earthquake? | Something that happens as a direct result of the earthquake |
What is a secondary effect of an earthquake? | Something that happens as a result of the primary effect. |
What can countries do for earthquake/tsunami prep? | Make emergency plans, do earthquake drills, use tsunami warnings and build earthquake resistant buildings. |
What is a tsunami? | An earthquake that occurs under the sea |
How do tsunamis happen? | Water becomes displaced and causes a tidal wave to form. |
What are fold mountains | Mountains that are made when two of the earths plates collide |
What is the up-fold of a fold mountain called? | An anticline |
What is the down fold of a fold mountain called? | The syncline |
What happens when an oceanic plate and a continental plate collide along a destructive plate boundary? | The heavier plate (oceanic) subducts under the lighter plate (continental). The continental plate buckled up due to the great pressure it has been put under. This is how fold mountains are formed over time. Magma can also well up to form a volcano. |
Give me an example of a fold mountain that formed from an oceanic plate and a continental plate. | The Andes formed when the Nazca and South American plates collided |
What are the two ways that fold mountains can form? | From two continental plates and from an oceanic plate and a continental colliding |
At what plate boundary do fold mountains form? | Destructive |
What happens when two continental plates collide | Continental plates are light, so no subduction occurs. Due to the great pressure, the plates are forced to rise upwards. The plates can buckle and fold to create fold mountains. |
Name a fold mountain formed by two continental plates | The Himalayas formed when the Eurasian and the Indo-Australian plates collided. |
Name all three of the different periods of folding | Alpine, Armorican and Caledonian |
What period of folding were the highest mountains in the world created? | Alpine |
When did the alpine folding period happen? | 30-35 million years ago |
What period of folding occurred when the Eurasian and African plates collided? | Armorican |
Give examples of Alpine mountains. | The Alps, the Andes, the Rockies and the Himalayas |
How many years ago did the Armorican period of folding happen? | About 250 million years ago |
What period of folding do the lowest mountains come from? | Caledonian |
Give an example of mountains from the Armorican folding period. | Galtee, MacGillycuddy’s reeks, Comeragh, Knockmealdown and the mountains of Black Forest |
What period of folding occurred about 400 million years ago? | Caledonian |
What period of folding happened when the Eurasian and the American plates collided? | Caledonian |
Name some mountains from the Caledonian folding period. | Dublin & Wicklow mountains, the Appalachian mountains in N America and the mountains of Norway, Sweden and Scotland |
What is geothermal energy? | Energy produced by the heat of the earth |