This is a draft cheat sheet. It is a work in progress and is not finished yet.
Some locations more at risk from tectonic hazards?
Key idea |
Question |
1.1 The global distribution of tectonic hazards can be explained by plate boundary and other tectonic processes. |
a. The global distribution and causes of earthquakes, volcanic eruptions and tsunamis |
Answer(Distribution):
Earthquakes are found around the Pacific Ring
of Fire, along the Mid-Atlantic Ridge,
throughout South East Asia and etc.....
Answer(causes):
Volcanoes are found near subduction zones
because the oceanic crust is being subducted
here causing magma to rise and form
volcanoes . They are also found on
constructive boundaries as magma is rising
through the gap left by plate movement to form
volcanoes .
Distribution of Plate Boundaries
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b. The distribution of plate boundaries resulting from divergent, convergent and conservative plate movements (oceanic, continental and combined situations). (Divergent):Plates also can pull apart from each other. This is known as a divergent boundary. A divergent boundary is a fault where the two plates are moving away from each other. Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges
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(Convergent):A subduction zone is formed at a convergent plate boundary when one or both of the tectonic plates is composed of oceanic crust. The denser plate, made of oceanic crust, is subducted underneath the less dense plate, which can be either continental or oceanic crust.
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(Conservative):At a conservative or transform boundary the plates slide past each other. Friction leads to tension between the 2 plates, which results in tension being released suddenly at the epicentre, creating an earthquake.
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Intra-Plate Earthquakes and Volcanoes
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c. The causes of intra-plate earthquakes, and volcanoes associated with hot spots from mantle plumes. Intra-plate earthquakes are caused by stresses within a plate. Since plates move over a spherical surface, zones of weakness are created. Intraplate earthquakes happen along these zones of weakness. The earthquakes may take place along ancient faults or rift zones.
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There is also volcanic activity bear the centre of of some hots spots. This is the result of the up-welling of hot molten material from the mantle boundary. It is also possible that large meteorite impacts create symmetrical hot spots on opposite sides of the planet when they collide with the Earth.
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