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Plate tectonics (Volcanic hazards (Lava flow (Usually quite slow thus…
Plate tectonics
Volcanic hazards
Lava flow
Usually quite slow thus possible to run away from it, basaltic lava can be more hazardous due to it being less viscous, but only seen at contructive volcanoes which are usualy in mid atlantic/pacific islands like Hawai
Pyroclastic flow
A fast cloud of hot ash, gas and magma, can travel up to 100 km/h, the most deadly hazard of a volcano as it is the hardest to escape.
Tephra/Ash fall
Very unlikley to be killed by tephra, however ash fall can induce bronchopnumonia and suffocation, as sharp rock causes lung damage
Lahars
Lahars are mud and water floods, as the shaking of the ground occurs as the volcano errupts liquefaction occurs thus resulting in a mixture of water and soil
Gas erruptions
Sulphur dioxide carbon monoxide and other poisonous gases are released from volcanic erruptions as the magma is gas charged, these gases are heavier then air and thus can fall into valleys
Jokulhaups
Melted glaciers from volcanic heat, can be a serious problem in glacial polar reigons, or at high altitudes, they can travel up to 3m/s and can be as wide as 100 km
Earth's Structure
Mesosphere
660 KM deep, and a point at which the seismic wave velocities dramaticly increase.
Outer Core
The liquid outer core, 5150 KM beneath the earths surface and 2200 KM thick, mostly made out of nickel and thus is a principle source of the earths magnetic feild
Athenosphere
Convection currents occur here aswell as the Benioff zone (In which subducting oceanic plates melt to form basaltic magma. 80-200 km bellow surface
Lithosphere
The Crust and very upper mantle, the area in which the tectonic plates lie
Oceanic plate
5-10 KM thick, basaltic at 3.0 g/cm^3
Continental plate
10-75 Km thick, granite/sedimentary at 2.7 g/cm^3
Inner Core
Solid due to high gravitational pressure and 5,150 to 6,276 km in depth. and a tempreture of 9000 F
Plate Boundary types
Convergent
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Produces fold mountains, e.g the Himmileas with the Indian Plate converging with the Eurasian Plate
Constructive
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Responsible for forming oceanic crust, as the plates move appart effusive basaltic magma cools to form oceanic crust, forming an oceanic ridge. This results in...
Plaomagnatism, the process in which the earths magnetic field changes the direction in which the magnetite within the basaltic crust changes direction based on the direction of the magnetic feild
Volcanic islands, islands formed by effusive balasatic lava from a constructive plate margin, an example being iceland, with the basaltic iceland volcanoe
Destructive
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Subduction Zone, the point at which the more dense oceanic plate with a density of around 3 g/cm^3, due to the weight of water, subducts under the less dense continental crust of around 2.7 g/cm^3 into the Benioff zone. Resulting in...
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Earthquakes
Scales
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Magnitude moment scale
1-8, each number is a magnitude (Multiplied by) 32
Effected by the amount of pressure built up in the plates underneath the surface, as more pressure in the rocks results in more pressure release which means more seismic waves.
Primary Impacts
Liquifaction
Shaking of the soil releases water that was kept in the pourous material, resulting in the soil to act like a liquid and rendering any foundations utterly useless.
Shaking
Love Waves
Most damaging, side sheer and up and down
S waves
Surface waves defined by a up and down motion parralel to the energy transfer, damaging
P waves
Compression waves that can travel through the liquid outer core, due to not needing chemical bonds for energy transfer, least damaging.
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