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(Length,Composition, Magnetism, Viscosity and why.)
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Natural Hazards aqa
The natural hazards unit from the AQA b module.
Question | Answer |
---|---|
What are the 4 layers of the Earth? | The Inner Core, Outer Core, Mantle and Crust |
Describe the Inner and Outer Core. (Length,Composition, Magnetism, Viscosity and why.) | The cores make up half of the Earth's diameter. They are made from Iron and Nickel and are where the Earths Magnetic fields come from. It is very dense and the Outer core is molten. High pressure in the center makes the inner core solid. |
Define; Molten | Something liquefied by intense heat. |
How is intense heat in the Inner core generated? | Intense heat is generated in the inner core by decay of radioactive elements like uranium. |
Describe the Mantle.(Length, Viscosity, touching) | The mantle goes from the core to the crust, a distance of about 2,900 km. It is mostly a semi-molten liquid on which the Earth’s crust floats. The heat from the core generates convection currents in the viscous mantle that cause the crust above to move. |
Describe the Crust.(Elements) | The crust is the thin layer of rock at the surface upon which we live. Eight elements make up over 98% of the Earth’s crust – although they are virtually entirely in the form of compounds. |
What is the Earths Crust made up of? | Tectonic Plates. These are like big rafts on the viscous, semi-molten mantle. |
Around how many Tectonic plates are there? | There are around 12 of these Plates. |
What is the moving of tectonic plates called, and what causes their movement. | Their moving is called continental drift, and their movement is caused by convection currents in the mantle. |
Name all 12 Tectonic Plates. | North American, Eurasian, African, Iranian, Arabian, Indo-Australian, Caribbean, South American, Philippine, Nazca, Antarctic, Pacific. |
What is the name scientists give to the former super-continent before it drifted apart due to continental drift. | Pangaea. |
What is the evidence for continental drift? | 1.They fit together like a jigsaw. 2.There are similarities in the rock layers from Africa and South America. 3.There are similarities in the type and age of fossils. 4.There is evidence of related species that definitely did not swim the Atlantic Ocea |
Name the tropics and their relativity to the equator as well as the angle. | Tropic-North Capricorn-South They are both 23.5 degrees away from the equator. |
Earthquakes happen where? | Earthquakes happen at all plate boundaries regardless of direction. |
Volcanoes happen when? | Volcanoes Occur when Oceanic and Continental plates move towards one another. Or when two Oceanic plates are moving apart where they form mid-ocean ridges. |
Point to Memorize; | Earthquakes and volcanoes occur in linear patterns in some parts of the world |
Point to Memorize; | In places, the North American and Pacific Plates are moving past each other. Volcanoes and earthquakes occur along the west coast of North America. |
Point to Memorize; | Many volcanoes and earthquakes are clustered together on islands and continents around the edge of the Pacific Ocean. Around the edge of the Pacific plate is an active zone called the ‘ring of fire’ |
Point to Memorize; | The North American and Eurasian plates are moving away from one another. Volcanoes can be found in a line running north to south down the middle of the Atlantic Ocean. |
Point to Memorize; | Australia is found in the middle of the Indo-Australian plate. Volcanoes and earthquakes are not found in Australia. |
Point to Memorize; | The east coasts of North and South America are not close to active zones. There are no volcanoes or earthquakes on the east coast of North or South America. |
Point to Memorize; | There is an active zone where the Nazca and South American plates move together. A belt of volcanoes and earthquakes is located along the west coast of South America |
Point to Memorize; | The Eurasian and Indo-Australian plates are moving towards each other. Many earthquakes happen in the Himalayan mountains to the north of India |
What happens at a construction plate boundary? | New Land is made. |
In detail what happens at a constructive plate boundary? | Plates at a constructive plate boundary move apart because of convection currents. During this magma rises from the mantle erupting as the plates slowly pull apart. The magma cools turning into igneous rock. This can make volcanoes, mountains or islands. |
What happens at a destructive plate boundary? | The Earth's crust gets destroyed at a destructive plate boundary? |
In detail what happens at a destructive plate boundary? | Oceanic plates are denser but heavier than the continental, so it is subducted. It is destroyed in this way. The crust is turned into magma, which can erupt through a volcano at the plate boundary and become lava. |
What is the Oceanic plate made of? | Basalt |
What is the continental plate made of? | Granite |
What happens at a conservative plate boundary? | The plates move side by side.(This may mean that they move in opposite directions or the same direction at different speeds. |
In detail what happens at a conservative plate boundary? | As they move past each other they often get stuck, building up great pressure until finally they jolt past each other. This sudden movement is what causes earthquakes. |
What happens at a collision plate boundary? | Two continental plates move together, where neither can sink a mountain/mountain range is formed. We may get earthquakes but not volcanoes because it is plates rising rather than subducting and becoming magma. |
Define Earthquake | A sudden movement within the earth’s surface, usually close to a plate boundary. |
Define Magnitude | The amount of energy that is given out during an earthquake. |
Define Focus | This is the point underground where the earth’s plates have moved. |
Define Epicentre | The point on the surface directly above the focus. |
Define Seismic Waves | These are waves of force that travel through the earth. There are two main types of wave, P waves and S waves. P waves are faster and can travel through solids and liquids whereas S waves are slower and can only travel through solids. |
Define Seismometer | An instrument used to measure the movement of the earth’s surface. A Seismometer records the vibrations from earthquakes. Mechanical versions work by way of a large mass, freely suspended. |
Define Seismograph | A graph produced by data collected from the seismometer. This shows the shaking of the earth |
Define Aftershocks | Aftershocks are smaller earthquakes formed as the crust around the displaced fault adjusts to the effects of the main shock. If an aftershock is bigger than 5.9 on the Richter scale then it is classed as an earthquake. |
Definition and Examples of Primary Effects in a Volcano | Primary effects of earthquakes happen straight away and occur as a direct result of the ground shaking. For example, shaking of the ground causing buildings to collapse; signs falling off walls; windows shattering; roads cracking; bridges toppling over. |
Definition and Examples of Secondary Effects in a Volcano | They Occur as a result of the primary effects, and happen later. E.g; fires caused by ruptured gas mains, disease caused by dead bodies that aren’t buried, sewerage pipes bursting and contaminating water supplies leading to death,liquefaction. |
What were the primary effects of the Kashmir Quake? | 1. 75% of Buildings collapsed. 2. 79,000 people were killed. 3. Landslides, and large cracks appeared in the ground. |
What were the secondary effects of the Kashmir Quake? | 1. Broken sewerage pipes contaminated water supplies and spread disease. 2. People died of cold during the harsh winter. 3. Impossible to reach some people because they were isolated by all the falling rubble. |
What were the short term responses to the Kashmir Quake | 1. The army and emergency services arrived to join the rescue effort. 2. Tents were given out by charities. 3. Aid workers arrived from abroad to find survivors and treat the injured. |
What were the long term responses to the Kashmir Quake | 1. Schools and hospitals were rebuilt. 2. Building regulations were improved to reduce damage and the death rate in future earthquakes. |
How many dead and Injured where there in the 1994 Los Angeles earthquake. | 72 Dead and Over 900 injured. $20 billion in Damages made it the one of the most expensive natural disasters to date in US history. |
Which plates boundaries does Los Angeles lie on | Los Angeles lies on the boundary between the Pacific Plate and the North American Plate |
Responses to Los Angeles Quake? R&R stands for Recovery and Reconstruction | 80,000 new housinng units were built The Red Cross got food and shelter in nearby schools in hours Food was given out in Dodger Stadium Almost all schools were reopened after a week of the quake |
Responses to Los Angeles Quake? R&R stands for Recovery and Reconstruction | Electricity supplies returned in hours The government compensated home owners The LA R&R Plan was written in light of the 1994 quake Stricter building codes were introduced |