Volcanoes and other Igneous Features - Essay Example

Jerry Ciacho May 08, Three Types of Faults A fault is a great fissure in the Earths crust where a part has been displaced against another part of the crust. This movement denotes that faults provide evidence that Earth is active. Fault movements are indications of great and potent forces deep under the ground. There are three known types of faults: the normal fault, reverse fault and strike-slip fault. Jointly, normal and reverse faults are referred to as dip-slip faults, since their movement happens along the direction of the dip, causing a movement going up and down respectively.

Compression is the pressure force of a reverse fault. The hanging wall slides going up past the footwall. The pushing forces that cause reserve faults are compressional which tries to thrust both the sides together. In a reverse fault, the hanging wall is the part that moves upward. Reverse faults are also occasionally called thrust faults. The term thrust fault is used to classify a fault with plates under the ocean. These kinds of faults can instigate more damage and destruction than strike-slips faults.

The massive Sumatra earthquake in 2004, which cracked the biggest fault length of any documented earthquake, is an example of a reverse fault earthquake.The second type of fault is the normal fault, in which the pressure force that causes it is tension. The hanging wall moves downward as the footwall slides past it, going up. The forces that generate normal faults pull both sides apart, or extensional. Although it is termed a normal fault, a normal fault is not the most frequently occurring out of all the other types of faults.

The term normal refers to the propensity for the movement of this type of fault to follow the direction of gravity. Examples of a normal fault are The Cabrillo Fault and The Great Rift Valley of Africa. Meanwhile, strike-slip faults have walls that instead of moving up or down move sideways. That is, the slide happens alongside the strike, unlike dip-slip faults, which occur up or down the dip. In these faults, the fault plane is typically vertical, thus, there are no hanging walls and footwalls.

The pressure forces causing these faults are horizontal, moving both sides past each other. The San Andreas Fault that runs through California is an example of a strike-slip fault.The majority of mountain ranges on Earth have been formed because of the compression along or within tectonic plates. Massive areas of bedrock disintegrate into blocks by faults. Landforms such as mountains, ridges, hills, valleys and lakes are occasionally created when the faults have a great vertical shift. Fault-block mountains frequently are a result from rifting, another sign of tensional tectonic pushes.

There are two types of block mountains: the lifted and the tilted. Tilted type block mountains have one gently inclining side and one sheer side with a bare scarp. These types of fault-block mountains are very common in the Basin and Range area of the western part of the United States. Works CitedGlascoe, Maggie. "Faults." The Southern California Integrated GPS Network. NASA, n.d. Web. 8 May 2012. Tarbuck, E.J. and Lutgens F.K. Earth: An Introduction to Physical Geology. Fifth Edition New Jersey: Prentice Hall, Upper Saddle River, 1996. Print.Twiss, R.J. and E.M. Moores.

Structural Geology. New York: W.H. Freeman and Company, 1992. Print.