Scribd
Upload
174 views7 pages

Plate Tectonics: Layers of The Earth

The document discusses plate tectonics and how the movement of tectonic plates results in different landforms and geological features. It describes plate boundaries, plate movements, and features created by constructive, destructive, and conservative plate boundaries such as mountains, trenches, and faults. It also discusses earthquakes, tsunamis, and ways humans can adapt to minimize risks.

Uploaded by

Teo Jia Ming Nickolas
Copyright
© Attribution Non-Commercial No-Derivs (BY-NC-ND)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
174 views7 pages

Plate Tectonics: Layers of The Earth

The document discusses plate tectonics and how the movement of tectonic plates results in different landforms and geological features. It describes plate boundaries, plate movements, and features created by constructive, destructive, and conservative plate boundaries such as mountains, trenches, and faults. It also discusses earthquakes, tsunamis, and ways humans can adapt to minimize risks.

Uploaded by

Teo Jia Ming Nickolas
Copyright
© Attribution Non-Commercial No-Derivs (BY-NC-ND)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 7

Plate Tectonics

Layers of the Earth


 Crusts
 Mantle
 Outer core
 Core

Tectonic plates
 Also know as crustal plates
 Consist of both continental and oceanic crusts

Plate tectonics
 Is a study of how plates move
 Is a study of why they move
 Is a study of how the movement changes the physical landscape

Plate boundaries and movements


1. Constructive plate boundaries

 They are divergent (Move apart)


 They create tensional forces

2. Destructive plate boundaries

 They are convergent (Move towards)


 They create compression forces

3. Conservative plate boundaries

 They are transform (Slide past)


 They create frictional forces

Physical features created by plate movement


Constructive plate boundaries
1. Oceanic-Oceanic crusts

 Ridges are formed E.G Mid-Atlantic Ridge


 Lava fountains may be found in the middle of the ridges

2. Continental-Continental crusts

 Rift valleys are formed E.G. East African Rift Valley


 Volcanoes may form

Destructive plate boundaries


1. Oceanic-Continental

 Fold mountains are formed E.G. Andes


 Trenches are formed E.G Peru-Chile Trench
 Volcanoes are formed
 Earthquakes occur

2. Oceanic-Oceanic crusts

 Oceanic trenches are formed E.G. Marianas Trench


 Volcanic islands are formed E.G Aleutian Islands
 Earthquakes occur

3. Continental-Continental crusts

 Fold mountains are formed E.G. Himalayas

Conservative plate boundaries


 Fault line are formed E.G San Andreas Fault
 Earthquakes occur

Results of plate movements


Folding
 Symmetrical
 Asymmetrical
 Recumbent
 Overthrust

Faulting
 Is the displacement of rocks along a crack or fault line

Normal
 When tensional force is applied, it causes a vertical displacement of rocks
 One block is lowered relative to the adjacent block, forming a steep scarp (slope)
 E.G. Teton Mountain

Reverse
 When compressional force is applied, one block is raised relative to the adjacent block, forming
an overhanging escarpment
 Over time, the overhanging escarpment would eventually erode

Horst
 It is a block mountain, that is formed due to faulting

Garben
 It is a rift valley, that is formed due to faulting

Vulcanicity
Vulcanicity
 It is the process hereby magma is forced to the Earth’s surface from within the Earth

Extrusive landforms (volcanoes)


Classification
 Active : Erupted frequently within 1000 years
 Dormant : Does not erupt frequently
 Extinct : Has not erupted since historic times

Features
 Magma chamber
 Vent
 Pipe
 Secondary pipe
 Crater
 Lava dome
 Secondary cone

Viscosity
 It is the resistance of a substance to flow
 Depends on the amount of silica in the lava and its temperature
 The higher the content of silica, the more viscous it is
 The higher the temperature of the lava, the less viscous it is

Types of volcanoes
Composite

 Is steeper at the top


 Is gentler at the base
 Has alternating layers of lava, ash and cinder
 E.G. Mount Fuji, Mount Saint Helens

Formation

 Viscous lava solidifies in the central pipe


 Gas pressure builds up as magma cannot escape
 When the pressure cannot be suppressed, eruption occurs
 Ash and cinder is thrown into the air, and falls near the vent
 Lava then falls over the ash and cinder

Shield

 Has gentle slopes


 E.G Mauna Loa in Hawaii

Formation
 The lava is basic and less viscous
 Hence it spread over a large area before solidifying

Acid lava

 Steep sides
 Dome shaped
 E.G. Mount Mayon in Philippines

Formation

 Acid lava is more vicious


 Hence it solidifies before it can travel far

Caldera and crater lakes

 Caldera is an enlarged crater


 It is formed by the collapse of volcano into magma chamber
 After the eruption of volcano, as magma is removed faster than it can be replenished

Usefulness of volcanoes

 There are fertile volcanic soils, which are excellent for growing crops.
 There are valuable minerals and precious stones such as gold, diamonds, copper and silver
 They are found in volcanic rocks
 Interesting volcanic landforms can lead to the development of the tourist industry
 Geothermal energy is an important source of clean energy for generating electricity

Earthquakes
Causes of an earthquake
 An earthquake is a sudden vibrations of the Earth’s crust.
 It is caused by the tectonic energy that is built up over time by plate movement, and released
rapidly
 At plate boundaries, the crust experiences enormous stress and the rocks are forced to bend
 Energy is gradually built up, and when it is released, the rocks snap and break along the fault
lines
 This releases seismic waves which causes the plates to vibrate violently, causing an earthquake

Features of an earthquake
 The focus of an earthquake is where the earthquake begins
 The epicenter of an earthquake is the point on the surface directly above the focus
Locations of earthquakes
 They are usually found along conservative plate boundaries or along fault lines
 They are also found along the Pacific Ring of Fire and the Trans-Eurasian Belt

How to measure the strength and magnitude of an earthquake


 Seismometer
 Richter scale

Effects of earthquakes
 Earthquakes can cause the collapse of buildings, bridges and flyovers
 Earthquakes can cause the rupturing of gas and water pipes
 Earthquakes can cause loss of lives
 Earthquakes can cause tsunamis
 Earthquakes can indirectly cause widespread fires
 Earthquakes can indirectly cause floods
 Earthquakes can indirectly cause power failures
 Earthquakes can indirectly cause water shortages
 Earthquakes can indirectly cause the spread of epidemics

Tsunamis
 Tsunamis are huge, towering waves that are caused by the vibrations of the sea floor

Human adaption to minimize the effects of earthquakes


Use technology to prevent fire hazards
 Electronic systems can be installed to cut off electricity and gas supplies automatically during an
earthquake
 This would minimize the danger of fire caused by bursting of gas pipes or live wires

Construct earthquake resistant buildings


 Buildings can be constructed to meet earthquake resistant standards
 High rise building should have flexible steel frames
 Smaller building should have concrete frames with reinforcing bars

Use technology to predict and monitor tectonic activities


 Advanced technology can be used to carry out accurate predictions of the occurrences of
earthquakes
 Accurate predictions and monitoring provide crucial information so the people living in the
affected areas can be warned
 They then can be evacuated before a disaster strikes

You might also like