tropical cyclones, volcanic eruptions, earthquakes

Question 1

conditions tropical cyclones

Answer 1

• deep layer of humid, warm (>27°c), and unstable air
• supply of energy (heat moisture) from sea surface
• circulatory motion of air, anti-clockwise in northern hemisphere, encouraged by coriolis force
  -wind shear encourages circulatory motion

Question 2

What is a hotspot and what happens at it?

Answer 2

• hotspots are locations beneath the earth’s crust where strong and rising currents of magma (known as plumes) occur
• where the crust above a plume is weak, volcanic activity occurs, e.g. hawaiian islands
• this also happens away from the edge of a plate boundary as there is a weakness in the crust

Question 3

describe how tectonic plates cause movement in plate boundaries?

Answer 3

• tectonic plates move due to convection currents in the earth’s mantle, caused by heat from core.
• constructive boundaries : plates move apart, allowing magma to rise, form new crust
• destructive boundaries : oceanic plate forced under continental plate due to subduction, creates earthquakes and volcanoes.
• conservative boundaries : plates slide past each other causing friction, leading to earthquakes

Question 4

explain how earthquakes are caused?

Answer 4

• caused by the movement of tectonic plates
• e.g example, at a conservative plate boundary
  two plates sliding past each other
• there is neither rising magma here, nor subduction so no volcanoes
• instead, the friction gives rise to earthquakes

Question 5

constructive plate boundary:

Answer 5

-two plates moving apart, e.g. in oceans
- magma (molten rock) rises to the crust to fill the gap, creates new crust through submarine volcanoes
- happens along the mid-ocean ridge in atlantic ocean

Question 6

state the similarities and differencesof 2 types of volcanoes

Answer 6

shield volcano:
-not as dangerousnot very explosive (but lava flows out)
-low viscosity
-frequent but not big eruptions

composite volcano: (strato)
-dangerous and explosive
-high viscosity
-not as frequent eruption

Question 7

destructive plate boundary:

Answer 7

-two plates moving towards each other, meeting head on
- the edge of one plate margin is being destroyed as it plunges beneath the other plate it is
- this is known as subduction
- molten rocks rise to the surface to form volcanoes
- friction between the two plates creates earthquakes

Question 8

conservative plate boundary:

Answer 8

• two plates sliding past each other
• there is neither rising magma here, nor subduction so there are no volcanoes
• instead, friction gives rise to earthquakes

Question 9

collision plate boundary:

Answer 9

• two plates meet head on (due of equal density and strength)
• sediments between two plates are squeezed upwards
• results in formation of fold mountains

Question 10

tropical cyclones causes

Answer 10

starts when high temperatures cause air to rise from sea
rising air - causes local thunderstorms
small storms come together - create strong flow of warm, rapidly rising air
produces area of increasingly low pressure

Question 11

what happens at the center (eye)?

Answer 11

there is a subsiding air with calm conditions, cloud skies. surrounding the eye is the eye wall where the most destructive energy occurs.