The Effects of an Earthquake
According to USGS at http://earthquakes.usgs.gov/learning/faq.php, an earthquake can cause many effects to the earth's surface that we may not realize. Ground shaking, which is the vibration and the shaking of the earth that we are all familiar with, is one of the most noticeable effects of an earthquake. The shaking is caused by two types of waves, body waves and surface waves. Body waves are waves which travel through the inside of the earth which are categorized into P and S waves. The vibrations began with the P waves moving back and forth in the same direction and in the opposite direction of the wave, followed by the S wave causing side to side vibrations. Surface waves are the waves that are within the surface of the earth. The combination of these two waves causes the earth to shake. Surface faulting, which we recognize as fractures in the earth, could be classified into three different types. Strike-slip is caused by a vertical fracture in the surface that has shifted horizontally. A normal fault is caused when there is a fracture in the surface of the earth and the surface moves down. And, if the surface moves up, it is a reverse or thrust fault. Deaths and injuries are less likely to occur because of faulting but the destruction that a fault can cause to structures can inadvertently cause deaths. The lengths of these faults can vary in miles. Ground failure is very common in areas where the surface is very close to the ground water. This induces liquefaction which is, the surface acts more like a liquid versus a solid. This weakens the surface which can cause many types of ground failure. Earthquakes can also cause landslides. The degree of the landslide is determined by the magnitude of the earthquake, the location and the condition of the surface. An undersea earthquake can cause a Tsunamis or water waves that can travel for miles beyond shore, at a height of 80 feet, and in a speed up to as much as 430 miles...
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