Causes And Effects Of Earthquakes Engineering Essay

Causes And Effects Of Earthquakes Engineering Essay Earthquakes are one of the most destructive mother-nature disasters in the world. An earthquake is defined as quake or tremor which there will be a slipping or movement of earth`s crust as a result of a sudden release of energy, accompanied and followed by a series of vibration on the ground that causing damages. The series of vibrations is known as seismic waves and can be measured using seismometer, a device which also records the seismic waves known as seismograph. This disaster may happen naturally or caused by human activities and very difficult to predict (Wikipedia, 2009). Earthquake can be grouped into three categories based on the depth of their foci that are shallow focus (300 km) Geological faults, volcanic activity, landslides, mine blasts and nuclear experiments will caused an earthquake. Strong earthquakes can cause severe damages and great loss of life in several ways, including fault rupture, tremors flood caused by tsunami and landslides. Earthquakes are generated b y either tectonic activity, the movement of large rock plates which underlay the earth’s surface, or volcanic activity (GEO.101-02, 2006). The areas that experienced the most active seismic are related with the plate tectonics that located on the ground. When the plate tectonics tend to moved, there will be faults that may be detectable on the ground surface, but they are often out of sight below layers of soil deposits. There is about 90 percent of the earthquakes case worldwide which occur at faults along the boundaries of earth`s major crustal plates. Deformation will occurred which resulted from the movement of tectonic plate. The type of deformation that takes place during earthquake generally occurs along zones where rocks fracture to produce faults that cause tremors (Stephen A.N, 2010). The faults will cause a stresses that form a movements of adjacent plates therefore energy will released. Within the earth rocks are constantly subjected to forces that end to bend, tw ist, or to fracture them. When rocks bend, twist or fracture they said to be deformed or strain. This deformations are the energy that been released from the fracture. The energy released in the form of ground shaking will result of tremors and trembling of the ground (NAHB Research Center, 1994). Figure 2.1 shows the location of earthquakes with different magnitude and depth. Figure 2.1 Locations of Earthquakes 2.2 Causes of Earthquake Earthquakes are caused by the sudden release of energy along faults plane. The strain that builds up in the rock will ruptures when the elastic limit of the rock is exceeded thus released the elastic energy as seismic waves. The greater released energy, the greater strain that stored in the rock. A sort of the energy that released by and earthquake will travels through the earth`s crust which caused damages to life and structures. The earthquakes can be even smaller and even larger (W.Spence, S.A.Sipkin, & George L. C, 1989). Earthquakes are three di mensional events which the waves will move outwards, horizontal and vertical plains. This condition produces three different types of waves which can be defined through its distinct behavior and some of this wave only travel through certain stratums within the earth. The three forms of these shockwaves that cause an earthquake are (Geography Sites, 2006):