In this article, in a SIMPLE and usefull way I described earthquakes, thier causes, thier types, and how can you measure them.
everything you might need to know about earthquakes is in this article.
An earthquake is the result of a sudden release of energy in the Earth’s crust that creates seismic waves, it is always un-expected and usually far more destructive, In the last earthquake that occurred in Haiti with a magnitude of 7Mw ,the Haiti Government reported that between 217,000 and 230,000 people had been identified as dead, an estimated 300,000 injured, and an estimated 1,000,000 homeless . So what is an earthquake and what makes it happen? How can we measure it? What is a seismic wave and in what forms can it be found? And how can we differentiate between different types of earthquakes? To give you a better idea about earthquakes, I am going to discuss all the previous questions in this report.
Earthquakes are produced by a sudden break in the rocks, usually near the surface of earth. From the point of break, energy travels out as a seismic waves which shake the surrounding rocks as they move through it, this vibrations sends different types of seismic waves through the earth crust that can travel for a very long distance , At the Earth’s surface, earthquakes gives their destroying effect by shaking and sometimes displacing the ground. If a large earthquake occurs in the sea, the seabed sometimes displaces causing a tsunami. In other words an earthquake is used to describe any seismic events.
An earthquake produces 2 major types of seismic waves that leaves the focus of the earthquake together, but travels at different speeds and reach a certain point at different times, and gives their effect in different forms:
A) The Body waves: Those kinds of waves depend on the temperature, composition and density of the surface they walk through, in other words they follow the ray path refracted by varying density and stiffness, this effect is the same as the refraction of any other light wave. Body waves are divided into two types of waves:
1- The p-waves: (primary waves, or pressure waves), those waves are longitudinal (formed by altering compressions and rarefactions) in other words the rock vibrate forward and backward, they are the fastest and the first to arrive, they can travel though solids and liquids at a speed of several kilometres per second.