“Earthquake - Shake, Rattle, & Roll” Submitted by: Dana Peebles
For Instructor: Stephen Underwood
July 14, 2014
PHSC 210-A02 Liberty University Online
Elements of Earth Science I. Introduction

Music can be calming and even sometimes relaxing. However, the only music that might describe an earthquake, would be the song “Shake, Rattle, and Roll”. The very nature of earthquakes cause us to get anxious, and there is nothing calming about the “earth moving under your feet.” In this short report, I will be giving a general overview of how earthquakes are formed and what causes them. I will also discuss the methods that seismologist use to study these occurrences. As humans, curiosity can get the best of us. This curiosity causes us to ask questions and seek further discoveries as to why these events happen. In addition, I will also talk about the new inquiries concerning earthquakes and what leads up to these questions that may still be unanswered.

II. General Overview

To understand how earthquakes form, what causes them, and the components that make it up, one must know exactly what an earthquake is. Webster’s Dictionary states that an earthquake is the “shaking or trembling of the earth that is volcanic or tectonic in origin.” While this describes the movement and the cause, it doesn’t describe why. Earthquakes happen when the underground rock immediately burst against the fault. This activity causes seismic waves that travel along the earth’s crust to vibrate. When this occurs, it is because the plates are being stretched or squeezed and the movement of the magma is building up pressure. After intense pressure, eventually it will move outside of the crust and continue in a motion outward an upward.

The cause of earthquakes falls into two categories. The first is the tectonic plate. In this category, the crust and upper mantle (also known as the lithosphere) generates movement. When this motion happens, the plates slide or rub against one another causing rocks to form at the base of the plates. Due to the friction of the plates rubbing, it often times creates a “snap back” effect. This process is known as the elastic rebound. A prime example of this would be what happened in the San Andreas Fault. The second cause of earthquakes is by volcanic eruption. This form does not happen as often as the tectonic plate form. However, when it does, it is because the magma has built up a great deal of pressure and begins to set off signals. These warnings are also known as “shocks.” An example of an earthquake caused by this form would be the San Francisco Fires.
The components that make up an earthquake are the before and aftershocks, the focus, and the epicenter. Once the quake forms by the outer layer of earth pushing against the sides of the fault, the rocks collide causing energy created waves through the earth’s crust. The waves, are known as the trembling or shaking we feel. The focus, is the point where all the activity begins. The breakdown or slipping of rocks and or plates, is the pivotal location of the earthquake. Right above the focus, is the epicenter. The epicenter, is the geological point from which the before and after shock waves radiate.

III. Methods of Study and Tools Used

Now that we know what earthquakes are, how they form, what the components are and what causes them, let’s look at how they are measured. Seismologist have been using a variety of tools to study the intensity and magnitude, as well as the activity of quakes for centuries. One of the first methods used, was the seismograph or seismometer. This method was given to us by the “Chinese astronomer and mathematician named Chang Heng.” The seismograph allowed recordable knowledge of distance and strength, as well as force and duration. This was done through pen marks on paper. The more activity of movement by the pen caused excessive “squiggly lines.” The lines and marks became the recording of seismic wave motions. Another form of measurement used was the Modified Mercalli Intensity Scale. This scale was introduced by Giuseppe Mercalli, and was used to specify the potency and effects of the quake. Lastly, was the Richter magnitude scale. The Richter scale, assigns a particular number to any given earthquake. The calculations of the number given is based off of the seismic waves and energy of the amplitude ratio. This in turn determines the magnitude. The Richter scale was invented by Charles Richter, an American Seismologist. The idea of using such measurements to study earthquakes, is to gain a better understanding and knowledge of not just one specific detail, but multiple aspects. The importance of each of these methods used together instead of singular will allow such knowledge.

IV. New Discoveries

When such catastrophic events such as earthquakes take place, one cannot take these events and not be effected by it in some way. Because of the outcome from such quakes, new discoveries have been made in how they are possibly formed. Much research and study has gone into these discoveries, and just like any other form of science, earthquakes are no different. The structure and repetitive behavior of the earthquakes allows observation and experimentation in these new discoveries. One possible discovery is the idea that it is not just plate tectonic and volcanic eruptions that cause earthquakes. New evidence suggest that it can be the fluid or gasses that cause the plates to store pressure and it isn’t just merely them moving that causes the vibrations. There has also been research done that is hopeful to reduce the amount of damage and injuries that may occur during such an event. Despite all of the research put into these discoveries, scientist are still left with several questions due to theories not being solved.

V. Unanswered Questions

Some of those unanswered questions include: Why we cannot predict earthquakes, what is the nature of the lava and chemistry of the breakdown in movement, as well as what the initial cause of stretching comes from. While these are only a few unanswered questions, there are many more. Science, and the earth are vastly changing every day. There will always be unanswered questions involving earthquakes and other topics relating to Earth. As long as there are people who are interested in finding out what the changes are, as well as how they happen, then there will always be ongoing studies and theories until we discover these mysteries.

VI. Conclusion

In conclusion, earthquakes have more than one form, and are caused by a variety of activity under the earth’s crust. The study of earthquakes is ongoing, and until theories have been solved new hypothesis will be given as to what, where, when, and why. The only logic anyone may have is that of an old joke suggesting “What did the ground say to the earthquake?” The only answer most of us will understand is “You Crack Me Up!” Works Cited

Birkland, T.(2007). Earthquake. In Encyclopedia of environment and society. Retrieved from http://www.liberty.edu:2048/login?url=http://literati.credoreference.com.ezproxy.liberty.edu:2048/content/entry/sageenvsoc/earthquake/0

Coffey, J. (2010). Universe Today. “How Earthquakes Happen”. Retrieved from http://www.universetoday.com/82050/how-earthquakes-happen/ Earthquake. (2011). In The American Heritage Science Dictionary. Retrieved from http://www.liberty.edu:2048/login?url=http://literati.credoreference.com.ezproxy.liberty.edu:2048/content/entry/hmsciencedict/earthquake/0

Earthquake. Merriam-Webster Dictionary. Retrieved from http://www.merriam-webster.com/dictionary/earthquake King, C., “I Feel the Earth Move: Tapestry” (1971). Ode Records.

Kishor, J., Wald, D.J., and Hearne, M. (2009). Estimating Casualties for Large Earthquakes Worldwide Using an Empirical Approach. USGS: Science for a Changing World. Retrieved from http://pubs.usgs.gov/of/2009/1136/pdf/OF09-1136.pdf

Lutgens & Tarbuck, “Foundations of Earth Science: Seventh Edition” (2014). Pearson Education, Inc. Upper Saddle River, NJ.

Lutgens & Tarbuck, (1989). “How Are Earthquakes Studied?” Retrieved from http://www.geo.mtu.edu/UPSeis/studying.html Measuring earthquake intensity. (2003). In Guide to global hazards. Retrieved from http://www.liberty.edu:2048/login?url=http://literati.credoreference.com.ezproxy.liberty.edu:2048/content/entry/philipsglobalhaz/measuring_earthquake_intensity/0

Nelson, S. (2012). Earthquakes and Earth’s Interior: Earth and Environmental Science. Tulane University, EENS 1110. Retrieved from http://www.tulane.edu/~sanelson/eens1110/earthint.htm Richter scale. (2013). In The Columbia Encyclopedia. Retrieved from http://www.liberty.edu:2048/login?url=http://literati.credoreference.com.ezproxy.liberty.edu:2048/content/entry/columency/richter_scale/0

University of Liverpool. (2006, December 14). Discovery Sheds New Light On Cause Of Earthquakes. Science Daily. Retrieved from www.sciencedaily.com/releases/2006/12/061213175137.htm

Valdiya, K.S., (2011). Some Burning Questions Remaining Unanswered. Journal of the Geological Society: Volume 78, Issue 4, Pages 299-320. Retrieved from
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