• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Seismology is the study of earthquakes and how the waves emitted from them travel through the earth.

Extracts from this document...


Seismology is the study of earthquakes and how the waves emitted from them travel through the earth. By studying how the waves pass through the earth, seismologists can tell which materials the waves have passed through, and the nature of these materials. This has helped us to build up knowledge of the earth's internal structure and an understanding of how earthquakes happen. To understand why earthquakes happen, we need to understand what is actually happening beneath the earth's surface. Very little is known about inside the earth, because we do not have access to it as the deepest borehole is only a mere 15 kilometers down. Much of what is known comes from studying the way earthquake waves pass through the earth. The earth consists of a number of concentric layers made up of many different rock types, and substances, which stretch from the inner core to the surface crust. There are three main parts which make up the earth, these are; the crust, the mantle and the core. The Core: The center of the earth consists of a molten outer part the outer core and a solid inner part called the inner core. ...read more.


Types of plate margin: Destructive: Constructive: Collision: Conservative: Colliding plates: When a continental plate meets an oceanic plate, the lighter continental plate moves of the more dense oceanic plate causing a trench to be formed, and over millions of years, mountain ranges are formed. When two continental plates collide, mountain ranges are formed, because neither descends because of the similarity in density. When two oceanic plates collide the slower moving plate is usually sub ducted underneath the faster moving plate. The areas where the oceanic plate descends beneath the continental plate are known as subduction zones. Zones like these have increased temperature and pressure this can cause metamorphism, which is when igneous and sedimentary rocks are changed into new types by recrystallization. Separating plates: When two plates move apart, new crust is created by magma, which comes up from the mantle to fill the gaps. Sometimes continental plates split and continents move apart, causing a rift valley which if flooded will form a sea. The boundaries between separating plates and splitting plates are constructive boundaries because new lithosphere is being formed. Conservative plates: At conservative plate margins the plates slide past each other, there is so much pressure building up until eventually the plate's move with a large jerk causing earthquakes. ...read more.


In some other areas, only P waves are detected. A shadow is cast by the absence of the S waves; this means that the outer core must be liquid. The size of the shadow means that the size of the outer core is about 7000km in diameter. Earthquakes also cause the earth to reverberate for a period of time after the earthquake, the reverberations we can deduce that inside the liquid outer core is a solid inner core about 2400km in diameter. Seismometers: A seismometer consists of a solid base, which should be secured to a rock or the ground. A pen on the base of a heavy mass is suspended above a rotating drum and on which graph paper is attached. As the earth moves in an earthquake, the heavy mass stays still and a jagged trace is drawn on the paper. The different traces produced are analyzed and deductions about the earths structure can be made, the velocities of the waves can be worked out by looking at the time delay between the earthquake and when waves are received. * OCR A Physics separate award * GCSE Physics T.Ducan * OCR a new introduction to Geography (GCSE) * GCSE Geography Revision notes * The Hutchinson Encyclopedia * The internet * Mr. Cocks's vast seismological Knowledge! ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Hazardous Environments section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Hazardous Environments essays

  1. Seismic waves.

    An S wave is slower than a P wave and can only move through solid rock. This wave moves rock up and down, or side-to-side. The arrow shows the direction that the wave is moving. Surface Waves Love Waves The first kind of surface wave is called a Love wave, named after A.E.H.

  2. What Is Seismology??

    Wave Type 1: Body Waves P Waves The first kind of body wave is the P wave or primary wave. This is the fastest kind of seismic wave. The P wave can move through solid rock and fluids, like water or the liquid layers of the earth.

  1. Earthquake is a shaking of the ground caused by the sudden breaking and shifting ...

    Even then, people should use extreme caution. A large earthquake may be followed by many smaller quakes, called aftershocks. People should stay clear of walls, windows, and damaged structures, which could crash in an aftershock. People who are outdoors when an earthquake hits should quickly move away from tall trees, steep slopes, buildings, and power lines.

  2. The focus of this paper will be the Queen Charlotte Islands earthquake of 1949.

    in a region to estimate when and where future earthquakes may occur. Secondly, seismologists use a geophysical method of study where they use observations and interpretations of changes in geometrical, metrical, thermal and chemical aspects of the earth's behaviour to indicate an approaching earthquake in an area (Tatsch).

  1. The study of earthquakes.

    National Earthquake Prediction ) the second theory is that, "earthquakes can be linked to explosive volcanic eruptions, where the sudden movement under ground causes a series of waves to be produced. The waves that cause earthquakes are referred to as P-Waves and S-waves.

  2. Free essay

    Quality of life increases as you travel away from the business district of London

    Traffic-related air pollution remains a key target for public health action in Europe. Conclusion In this conclusion I will set out my study and determine whether my hypothesis 'Quality of life increases as you travel away from the business district of London' is correct.

  1. The origin of the Earth

    Carbon dioxide also dissolved into the oceans. The ammonia and methane in the atmosphere reacted with the oxygen. Nitrogen gas was released, partly from the reaction between ammonia and oxygen, but mainly from living organisms such as denitrifying bacteria. (remember that nitrogen is a very unreactive gas and it has built up slowly).

  2. Volcanic and seismic events are major pieces of evidence towards proving that plate-tectonics theory ...

    The same is true of a rock?s paleomagnetic inclination, which thus provides a record of the geographic latitude where the rock formed. In the 1950s, geophysicists studying paleomagnetic pole positions found evidence suggesting that the Earth?s magnetic poles had wandered all over the globe for at least the past several hundred million years.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work