Are Earthquakes Becoming More Frequent: GCSE Case study
During this case study, I will be investigating a question: are earthquakes are becoming more frequent? Throughout this investigation, I will be explaining how earthquakes are detected, how they are caused, presenting an argument for and against this debate etc. At the end of my case study, I will formulate an opinion based on the evidence that I have gathered. I will also be questioning the reliability of my sources of information. If you want to analyse the sources yourself, the links to the websites will be available on the bibliography page.
I will also acquire statistics to further support the argument being made by both sides. Diagrams will give visual aid to help understand this controversial issue. (Picture of earthquake damaged buildings) What are earthquakes? Firstly, Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don’t just slide smoothly; the rocks catch on each other.
The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that’s built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake. (picture showing epicentre of earthquake) Earthquakes can cause a lot of damage.
Earthquakes have the power to uproot trees and send them crashing into buildings. They can trigger landslides and avalanches, and cause flooding and tsunamis. Human structures are also at risk. It is interesting to note that tall buildings will sustain the least damage if they are located directly at the epicenter. This is because they can withstand the up-and-down motion of P-waves. S-waves, on the other hand, occur far away from the epicenter, and cause the greatest stress by shaking buildings from side to side. These buildings are often knocked off their foundations. (Diagram of P and s-waves)
