Plate Tectonics and Associated Hazards

I hope these are helpful!

HideShow resource information
Preview of Plate Tectonics and Associated Hazards

First 254 words of the document:

Plate
Tectonics
and associated hazards
Plate movement
Earth structure, plate tectonics theory: convection currents and sea-floor spreading. Evidence: continental drift
and palaeomagnetism.
Destructive, constructive and conservative plate margins. Processes: seismicity and vulcanicity.
Associated landforms: young fold mountains, rift valleys, ocean ridges, deep sea trenches and island arcs.
Hot spots associated with plumes of magma and their relationship to plate movement.
Vulcanicity
Variations in the type and frequency of volcanic activity in relation to types of plate margin and types of lava.
Forms of intrusive activity ­ dykes, sills, batholiths.
Minor forms of extrusive activity ­ geysers, hot springs and boiling mud.
Major forms of extrusive activity ­ types of volcanoes.
Two case studies of recent (ideally within the last 30 years) volcanic events should be undertaken from
contrasting areas of the world. In each case, the following should be examined:
· The nature of the volcanic hazard
· The impact of the event
· Management of the hazard and responses to the event
Seismicity
The causes and main characteristics of earthquakes: focus and epicentre; seismic waves and earthquake
measurement.
Tsunamis ­ characteristics and causes.
Two case studies of recent (ideally within the last 30 years) seismic events should be undertaken from
contrasting areas of the world. In each case, the following should be examined:
· The nature of the seismic hazard;
· The impact of the event;
· Management of the hazard and responses to the event.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Plate Movement
A Background to Plate Tectonics
Earth is 4.6 billion years old
o Started as a ball of molten materials
o Slowly cooled from surface inwards to form a crust of solidified rocks
o Gases escaping from volcanic activity formed an atmosphere
o Many asteroid impacts and wasn't yet able to support life (no oceans, no clouds, no
flowering plants)
The oldest preserved and known rocks are dated between 2.5 and 3.…read more

Page 3

Preview of page 3

Here's a taster:

The Theory of Tectonics
The crust is fractured into huge
segments called tectonic plates
o These plates are moving
slowly by convection
currents within the mantle
Beneath the earth, temperatures
start to rise in the mantle (a zone
of molten silicates and other
minerals)
o The boundary is
transitional
o The zone is known as asthenosphere (or Mohorovicic Discontinuity)
The Earth has a solid core of iron and nickel (despite temperatures of 6200 C) due to
intense pressures
o There is transitional zone between the…read more

Page 4

Preview of page 4

Here's a taster:

The Crust
The crust is divided into chunks of solid rock called tectonic plates
The major plates:
o Pacific
o Eurasian
o African
o Antarctic
o North American
o South American
o Indo-Australian
o Other smaller plates
The plates are made of different materials:
o Continental
Thicker, older, lighter
Made of granite, silica and aluminium
35km thick but thicker underneath
mountain chains
1,500 million years old
o Oceanic
Subduction zones (destructive)
Younger and heavier
Made of basalt, gabbro and magnesium
200 million years old
6-10km…read more

Page 5

Preview of page 5

Here's a taster:

Vulcanicity
Volcano and Earthquake Location
This
map
shows how some of the world's volcanoes and earthquakes occur along tectonic plate boundaries.…read more

Page 6

Preview of page 6

Here's a taster:

Glacial evidence
o There is wide spread distribution of permocarboniferous glacial sediments in South
America, Africa, Madagascar, Arabia, India, Antarctica, and Australia
o The continuity of glaciers (striations and deposits) suggest the super continent
existed called Gondwanaland
o Striations indicated glacial flow towards the poles from the equator and supports the
idea that the southern continents have previously been in dramatically different
places as well as next to each other
Paleomagnetism and the age of rocks along the Mid Atlantic Ridge
o Magnetic strips running…read more

Page 7

Preview of page 7

Here's a taster:

Plates are moving apart from each other
What happens at this Magma rises to the surface of the earth
boundary? When magma reaches the surface, it cools and solidifies to
form a new crust of igneous rock
Earthquakes often accompany magma rising
Volcanoes and
Volcanoes form when the magma builds up enough (called
earthquakes?
shield volcanoes)
Mid-ocean ridges ­ continuous uplifted features on the
surface of plates
Transform faults occur at right angles to the plate boundary
Landforms and features? and the spreading of these…read more

Page 8

Preview of page 8

Here's a taster:

Conservative
Plates are sliding past each other, either in the same or the
What happens at this
opposite direction
boundary?
There is no destruction or creation of the crust
There is no volcanic activity
Volcanoes and Earthquakes are caused because friction is caused as the
earthquakes? plates rub against each other and the stress builds up only to
release itself as shallow-focus earthquakes
Landforms and features?
The San Andreas fault in California, where the Pacific and North
American plates move parallel to each other.…read more

Page 9

Preview of page 9

Here's a taster:

Destructive
(oceanic and
continental)
The oceanic crust moves towards (and disappears into the
mantle of) a continental plate
What happens at this This is because the denser oceanic plate is forced beneath
boundary? the continental plate into the subduction zone
As the oceanic plate is forced downwards, it melts due to the
heat from friction and the hotter surroundings
Because the molten rock from the melting oceanic plate is
Volcanoes and
lighter, it rises to the surface and forms explosive volcanoes
earthquakes?
Earthquakes (shallow, intermediate…read more

Page 10

Preview of page 10

Here's a taster:

Destructive
(oceanic and
oceanic)
The plates are moving towards each other
What happens at this
When oceanic plates meet, one is forced under the other and
boundary?
the processes of subduction begin
Because the molten rock from the melting oceanic plate is
Volcanoes and
lighter, it rises to the surface and forms explosive volcanoes
earthquakes?
Earthquakes (shallow, intermediate and deep)
Oceanic trenches
Landforms and features?
Island arcs
An example is where the Pacific plate is being subducted
beneath the smaller Philippine plate.…read more

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all resources »