Earthquakes belong to the class of most disastrous natural hazards. They result in unexpected and tremendous earth movements. These movements results from dissemination of an enormous amount of intense energy in form of seismic waves which are detected by use of seismograms. The impact of earthquakes leaves behind several landmarks including: destruction of property, extensive disruption of services like sewer and water lines, loss of life, and causes instability in both economic and social components of the affected nation (Webcache 2). How Earthquake Happen The interior structure of the earth is made up of crust, the mantle and core (inner core and outer core). Earthquakes occur on the crust. Crust forms the external layer of the earth surface. On the crust, the plate tectonics forces are in charge of causing the abrupt earth movements. Due to the existence of an immense temperature and concurrent pressure difference in the outer layer and inner layer of the earth, convection currents occur at the mantle. This energy results from overwhelming decomposition of radioactive substances contained by the rocks found at the interior of the earth. The developed convection currents lead to movement of lava; cold lava finds its way to the interior of the earth crust, while the molten lava which is generally hot, leaves the interior of the earth to the outside of the earth crust. These kinds of circulations occur at different locations of the earth surface and consequently results in segmentation of the earth due to movement in different directions. The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3). Due to the fact that rocks are composed of high intensity of elastic and brittle material, they therefore store considerable amount of strain energy that results from elasticity, during the action of plate tectonic. The brittleness leads to development of concurrent cracks on the rocks as a result of plate’s action.
The Mantle makes up 70% of the Earth’s mass and is mostly solid but capable of flow, causing changes in the Earth’s surface.
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
Seismic studies show that the mid-oceanic ridges experience an elevated number of earthquakes. All these observations indicate intense geological activity at the mid-oceanic ridges. Periodically, the Earth's magnetic field reverses. New rock formed from magma records the orientation of Earth's magnetic field at the time the magma cools. Study of the sea floor with magnetometers revealed "stripes" of alternating magnetisation parallel to the mid-oceanic ridges.
Magmas in island arc settings consist primarily of components from two different origins, the slab component, and the mantle wedge. The mantle wedge may melt due the descent of the slab, giving the main portion of the non-slab component. The slab component is derived from the subducting slab as it descends. This may consist of melting of the crustal portion of the slab, but also melting of the mantle wedge due to addition of water driven off the slab. Since the descending slab is composed of old, cold oceanic crust, there is a slight paradox in the idea of melts forming from it. However, frictional heat, as well as the heat of the underlying mantle, can drive hydrous fluids off the slab. (Machado, Chemale Jr., Conceição, Kawashita, Morata, and Van Schmus, 2003; Kimura and Yoshida, 2006).The addition of water to the mantle wedge results in the lowering of melting temperatures, allowing melts to be formed at much lower temperatures than might otherwise be expected. Also, the circulation of hot fluids allows materials dissolved in them to migrate upwards ...
Regina:The Early Years. (2014). Cyclone of 1912. Regina: The Early Years 1880 -1950. Retrieved March 7, 2014, from http://scaa.usask.ca/gallery/regina/central/cyclone.html
GEOS1001: Assignment 1 – Topic 1: Discuss the role of mantle/core convection and plate tectonics as a life-support system on Earth, and outline other factors that make our planet unique in the Solar System.
Science of Everyday Things. (2002). plate tectonics Facts, information, pictures | Encyclopedia.com articles about plate tectonics. Retrieved from http://www.encyclopedia.com/topic/plate_tectonics.aspx
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
benchmark for the future, and integrated investigation into the effects of earthquakes in the U.S.
Basalt forms due to the partial melting of the layer of the mantle called the asthenosphere. The asthenosphere is the plastic zone of the mantle beneath the rigid lithosphere. Mantle plumes coming from the mesosphere can cause the asthenosphere to melt with heat or even if pressure decreases, which is called decompression melting (Richard 2011). The magma that forms from this melting is mafic magma that solidifies once it reaches the earth’s surface and cools quickly. The above process mainly occurs mainly during intraplate igneous activity which is the main explanation for volcanic activity that occurs a long distance away from a plate boundary. If the tectonic plate above the mantle plume is moving it can create a string of volcanic activity such as in Hawaii. See Fig 2.
Convection currents deep in the mantle of the earth, begin to well up towards the surface. As the pressure increases, it sets the crustal plates in motion. There are different kinds of mountains - Volcanic, Folded, Fault-block, and Dome mountains. Volcanic mountains are formed when magma comes up through cracks in the Earth’s crust and explodes out of lava and ash. The Hawaiian volcanoes, Mt. Hood, Mt. Etna, Vesuvius, and Mt. Saint Helens is an example of volcanic mountains.
They reshape the surface by three plate movements, the convergent boundary, the divergent boundary, and the transform boundary. The Convergent Boundary also known as the destructive plate boundary is what creates mountains. In this boundary, two plates collide with one another, destroying some of the earth’s crust on impact. There are three different results that come from plates colliding depending on which ones crash into one another. When oceanic and continental plates collide, it causes one plate to subduct and sink into the mantle, the plate that subducts is typically the oceanic lithosphere because it is less dense. When two oceanic plates collide one plate may be forced under the other, causing magma to rise, creating volcanoes. The third result occurs when two continental plates collide, the impact from these two plates colliding forms mountain ranges. There are five different types of mountains, including Fold, Fault block, Dome, Plateau, and Volcanic
They are the earth’s crust; they move very slowly every year. As the tectonic plates slide over each other they cause earthquakes. Earthquakes produce various damaging effects this includes damage to structures of buildings, bridges and other standing formations which then...
There are many different types of plate movements that can easily cause an earthquake. An earthquake is a pulsation that can be brutal and murderous, of the Earth’s surface that allows a release of energy in the Earths crust. A scientific understanding of earthquakes is very important in today’s society. As the earth’s population increases, the expanding of the people can be a scary thought if an earthquake is near. With a higher understanding of the cause and effects of earthquakes, we should be able to lower the damage, loss, and suffering of life from these deadly