The Sub-Surface of the Planet: Observations verses Inferences

Our understanding of the Earth’s interior has been a focus for scientific study for multiple decades, recognised in the early 1900’s. Throughout the years, scientists have debated and quarreled over their findings, observations and theories for the most correct model of the composition and internal structure of the Earth.

Earthquakes play a major role into understanding the composition and materials that exist within the Earth (Merali and Skinner, 2009, p.252). Earthquakes are the main source of insight into the inner workings of the earth, due to the nature of the seismic waves they produce. P and S waves are reflected and refracted at different boundaries within the earth, and this enables seismologists to make inferences about the internal composition and structural of planet Earth. (Merali and Skinner, 2009, p.252).

In 1906, a scientist by the name of Richard Dixon Oldham had suggested a theory structured another scientists findings by the name of Emil Wiechert. Oldham had identified that S waves and P waves behaved differently and could be used to explain and illustrate that previous theories were not entirely correct (Merali and Skinner, 2009, p.253). Through the analyzation of arrival times of these waves, Oldham had drawn an conclusion that p waves and s waves react differently in terms of being refracted, reflected or absorbed depending on the state of the material as shown in Figure 1.(Tarbuck, Lutgens, Tasa, 2013, p.143). Oldham had developed this theory of the Earth not being the same state due to these effects of seismic discontinuity which are shown in Figure 1., consisting of refraction, reflection and absorption. The changes that are displayed from this idea are; the speed of the waves due to a refraction occu...

... middle of paper ...

... the the composition of the core and mantle (Merali and Skinner, 2009, p.259), (Tarbuck, Lutgens, Tasa, 2013, p.397-406).

Ultimately the development of previous inferences and observations which have developed our current model for the Earth’s composition and interior structure are a key concept in understanding our future developments towards resourcing our planet and understanding how it works to a further degree.

Bibliography

Merali Z., Skinner B.,2009, Visualizing Earth Science, 1st Ed, John Wiley and Sons, Hoboken, New Jersey.

Tarbuck E., Lutgens F., Tasa D., 2014, An Introduction to Physical Geology, 5th Ed, Pearson Education, Upper Saddle River, New Jersey.

Elsasser W., 1950, Review of Modern Physics, The Earth’s Interior and Geomagnetism, 22, 2-20.

Herndon J. M, 2005, Current Science, Scientific Basis of Knowledge of Earth’s Composition, 88, 1034-1036)