Earthquakes

I chose to research earthquakes and the prediction of earthquakes because I was curious as to how they work. In this paper, I will discus the history of earthquakes, the kinds and locations of earthquakes, earthquake effects, intensity scales, prediction, and my own predictions.

An earthquake can be defined as vibrations produced in the earth's crust. Tectonic plates have friction between them which builds up as it tries to push away and suddenly ruptures and then rebounds. The vibrations can range from barely noticeable to a disastrous, and destructive act of nature. Six kinds of shock waves are generated in the process. Two are classified as body waves, that is, they travel through the inside of the earth and the other four are surface waves. The waves are further classified by the kinds of motions they incur to rock particles. Primary or compressional waves, known as P waves, send particles moving back and forth in the same direction as the waves are traveling, as secondary or transverse shear waves, known as S waves, create vibrations perpendicular to their direction of travel. P waves always travel at faster speeds than S waves, so whenever an earthquake occurs, P waves are the first to arrive and to be recorded at geophysical research stations worldwide.

During ancient times very little was know about. Some of the ancient Greek philosophers connected earthquakes to underground winds, where others blamed them on fires in the depths of the earth. Around AD 130 the Chinese scholar Chang
Heng, believing that waves must ripple through the earth from the source of an earthquake, created a bronze object to record the directions of such waves. Eight balls were carefully balanced in the mouths of eight dragons placed around the outside of the object. When a passing earthquake occurred the wave would cause one or more of the balls to drop.

Earthquake waves were observed in this and other ways for centuries, but more scientific theories as to the causes of quakes were not proposed until modern times. One such concept was recreated and advanced in 1859 by an Irish engineer, Robert
Mallet.

Perhaps recalling on his knowledge of the strength and behavior of construction materials, Robert Mallet proposed that earthquakes occurred "either by sudden flexure and constraint of the elastic materials forming a portion of the earth's crust or by their giving way an...

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...orth of the earthquake that occurred the day before, this time I was wrong, there were two that occurred near the San Francisco bay area and none within a 50 mile radius of my approximation. The next couple days I predicted earthquakes that were within a 100 mile radius than were they actually occurred. From my experiments I concluded that predicting earthquakes was easy, you just have to pick a spot on the fault. The only thing that troubled me and probably most scientists, is magnitude, there is no possible way of predicting an earthquakes magnitude. Which is what we are really trying to predict. Earthquakes happen all the time, but what we are really trying to figure out how to predict is when a major earthquake is going to occur.

I learned that earthquakes are almost unpredictable, and devastating acts of nature. I also learned how earthquakes occur and almost all of the "earthquake dictionary". There is still alot more to be known about earthquakes that we still do not know about today. Prediction of large earthquakes is still under development, where prediction of small, unnoticeable earthquakes can be easy to predict because they happen mainly around fault lines.