Explain, with Reference to Examples That You Have Studied, How the Theory of Plate Tectonics
Explain, with reference to examples that you have studied, how the theory of plate tectonics helps to explain the distribution of earthquakes around the world
Intro
Everyday there are several 100 earthquakes across the globe. All of the Earths major earthquake zones are found along the faults at plate boundaries.
What are earthquakes?
Seismic waves are the vibrations of energy created from the plate movement which cause earthquakes. These different waves can be seen using a seismograph. First waves are known as primary waves and are the fastest travelling waves. They do not have much energy and cause little damage. Secondary waves have much more energy and cause the crust to move up and down. Surface waves are responsible for all damage. They move slowly along the surface, moving it up and down and side to side.
Parts
The fault line refers to the gap between two tectonic plates, where nearly all earthquakes occur. As plates attempt to move past each other, friction is caused between layers of rock. Pressure builds causing an earthquake. The focus is the point where the Earthquake begins. The epicentre is the point on the surface just above the focus. Seismic waves are strongest at the epicentre and if an urban region is close or near it, a huge amount of damage will be inflicted. Such an event happened in Haiti 2010.
Destructive
The most common and intense earthquakes occur along subduction zones, meaning oceanic-continental, or oceanic-oceanic plate boundaries. Japan experienced an earthquake in 2011 when the Pacific Plate subducted under the Eurasian Plate. Earthquakes also occur between two continental plates. The pressure generated causes earthquakes to occur at shallow depths.
Passive
The San Andrea’s Fault is the world’s best-known passive plate boundary. It formed between the Pacific and North American Plates. As these plates slide past each other, pressure is released, causing a violent Earthquake. In 1906 The San Andreas Fault caused an earthquake measuring 8.3 on the Richter scale. Seismologists are predicting ‘The Big One’ to occur by 2034
Divergent
These earthquakes occur along mid-ocean ridges. The Mid Atlantic-Ridge causes earthquakes when plumes of magma are forced through the gaps triggering small earthquakes.
Summary
Intro
- Everyday there are earthquakes
What are they?
- Seismic waves, vibrations, seismograph, primary, secondary, surface
Parts
- Fault lines, friction, pressure, focus, epicentre, Haiti 2010
Destructive
- Oceanic-oceanic, oceanic-continential, Japan 2011, Pacific, Eurasian, continential-continental, shallow debths
Passive
- San Andreas Fault, pacific, N.A, violent, 8.3, Richter scale, 1906, 2034
Divergent
- Mid-ocean ridges, Mid- Atlantic, magma, small earthquakes