...Describe the type of tectonic and seismic activity which occurs at each plate boundary (25 mark) In the theory of plate tectonics, the earth's crust is broken into plates that move around relative to each other. As a result of this movement, three types of plate boundaries are formed: Divergent, Convergent- Oceanic/Continental & Continental/Continental, and Transform boundaries. Not all plate boundaries fit into the main groups shown above. In some parts of the world the boundaries are not easily defined because the deformation caused by the plates covers a wide area rather than having clearly defined plate edges. This deformation is called a plate-boundary zone. The smaller fragments of plates are called microplates. The destruction of the earth’s crust occurs along plate boundaries, where plates are moving towards each other and the creation of the crust occurs where plates are moving away from each other. A divergent plate boundary, also knows as an constructive or extensional boundary) is a tectonic boundary where two plates are moving away from one another forming new crust as magma rises from the earth’s surface between the two plates. The boundaries are found along spreading centres -The Mid-Atlantic ridge being an example of a ‘textbook’ slow spreading centre and in contrast the East Pacific Rise is an example of a fast spreading ridge. Divergent boundaries can be Continental or Oceanic. When a divergent boundary occurs underneath ocean lithosphere, the rising...
Words: 1085 - Pages: 5
...Seismic and volcanic events are major pieces of evidence towards proving that plate tectonic theory is valid. Discuss the extent to which you agree with this view. (40) Plate tectonics is the theory that explains the structure and motion of the Earth’s lithosphere. The theory states that the Earth’s crust is split into large sections called tectonic plates, and these move relative to one another creating boundaries at which plates converge, diverge and move past each other. Alfred Wegener pioneered the theory of continental drift in the early 1900s which he supported with multiple pieces of evidence. Perhaps the earliest indicator of the theory was the apparent fit of some of the Earth’s continents; analysis of these coastlines, notably the eastern edge of South America and the western edge of Africa, has shown that they are very similar geologically suggesting that at some point in the Earth’s history the landmasses were joined together. Another indicator that the continents were once distributed differently was geological evidence of glaciation in India – it is unlikely that glaciers could ever reach such low latitudes, but this problem can easily be explained by continental drift. Fossil distribution also provided some of the earliest evidence for plate tectonics – certain land-dwelling fossil species have been found in areas that are now separated by ocean which indicates that those areas were at some point joined together. However at the time of Wegner’s work many of the...
Words: 981 - Pages: 4
...Evolution and Theory of Plate Tectonics The most important and vital development of plate tectonic theory and evolution appeared to be among the most crucial scientific achievements in the 20th century. The theory concept offers a relevant structure towards the knowledge of all natural Earth attributes. It additionally provides one particular framework with regard to the knowledge of both planet's origin and outlook. Notably, the evolution of life on the planet remains significantly impacted by plate tectonic processes. This may involve the historic, societal, and cultural advancement of humanity. In other words, plate tectonic theory is an encompassing conjecture regarding different scientific theories that demonstrate the naturally occurring Earth characteristics have actually formed the historical past from the solid Earth, the oceans, the atmosphere, and all life organisms. Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics). Like these other foundational scientific theories, the theory of evolution is supported by so many observations and confirming experiments...
Words: 1128 - Pages: 5
...Wegener's theory Continental drift-In 1915, the German geologist and meteorologist Alfred Wegener first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. The fossil record supports and gives credence to the theories of continental drift and plate tectonics. Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It formed approximately 300 million years ago and then began to break apart after about 100 million years. Unlike the present Earth, much of the land mass was in the Southern Hemisphere. Pangea was fully assembled by the Early Permian Period, some 270 million years ago. It began to break apart about 200 million years ago, during the Early Jurassic Period, eventually forming the modern continents and the Atlantic and Indian Oceans.The giant ocean that surrounded the continent is known as Panthalassa. The movement of Earth's tectonic plates formed Pangaea and ultimately broke it apart. Pangaea existed during the Permian and Triassic geological time periods, which were times of great change. This therefore shows that a certain extent of tectonic activity took place 200 million years ago to form our world that we know today. The idea of Pangea fitting together in a jigsaw fashion compared to how convection currents dictate the movement of the plate boundaries it can be seen as tangible that these pieces were to fit together very easily, however certain processes of...
Words: 1050 - Pages: 5
...Due date: ___________________ Name ___________________________________________ Plate Tectonics Exercise (20 points) PLATE BOUNDARIES There are three different types of lithosphere plate boundaries associated with different types of topographic features and tectonic activity. These are: Divergent boundaries (also called “spreading centers). At divergent boundaries, plates are moving apart. The most common kind of spreading center is the midocean ridge where new ocean floor is created. Spreading may also take place within a continent. In this case, blocks of crust may drop down as the land is pulled apart, creating a rift valley. Convergent boundaries These boundaries involve collision of lithosphere plates, which may occur in three different circumstances. 1. Oceanic – continental plate convergence. If the edge of an oceanic plate collides with the edge of a continental plate a subduction zone is formed. The denser oceanic plate subducts (plunges) beneath the continent, producing a deep oceanic trench. As the oceanic lithosphere descends, partial melting of the rock along the contact zone occurs. The magma that is produced rises toward the surface and produces a chain of volcanic mountains on the land mass parallel to the collision boundary, such as the Andes in South America. 2. Oceanic – oceanic plate convergence. In this case, subduction also takes place. A deep ocean trench forms along with a chain of volcanic islands. An example of such an island arc is the Aleutian...
Words: 1880 - Pages: 8
...typically events which occur as a direct result of a volcano, where debris and molten rock are both extruded and intruded during an eruption. The plate tectonic theory was developed by Alfred Wegener in 1912, however initially his theory of how the plates all ‘fit together’ was ignored as there was simply not enough evidence. After technology had significantly advanced later in the 20th Century, the theory was developed further by several scientists. This theory suggests that the crust is split into a number of plates, all of which float on molten mantle rock and are constantly moving on the Earth’s surface. We are also now aware that there are two types of plate, oceanic and continental and it is the movement of these two plates that can cause both volcanic and seismic events. However these events are not the only pieces of evidence that prove the plate tectonic theory is valid; there are many other factors which include sea-floor spreading and fossil distribution. Pyroclastic materials and molten magma escape the mantle and emerge above the Earth’s crust through volcanos. All of Earth’s active volcanos are distributed in clusters around the pacific ocean, southern Europe, the east coast of Africa and through the Atlantic Ocean. These specific locations are all as a result of the nearby constructive and destructive tectonic plate boundaries, this is known as ‘The Ring of Fire’. It is named so because of the large concentration of a large, ring like formation of volcanos around...
Words: 1586 - Pages: 7
...Lesson 1 Earthquakes, Volcanoes and Plate Tectonics Time Frame: Two to three periods I. Objectives At the end of the lesson, the students should be able to: 1. discuss the tectonic activities that happen at plate boundaries; 2. discuss some consequences of having the Philippines in a tectonically active zone; 3. explain why the Philippines experiences many earthquakes; and 4. explain why the Philippines has many volcanoes. II. Subject Matter A. Topic: Earthquakes, Volcanoes and Plate Tectonics B: References: Earth Science: Philippines in Focus, pp. 34-36 C. Materials: Map, Pictures III. Learning Tasks/Procedure A. Motivation/Recall 1. Show the completed jigsaw puzzle in Lesson 21 and guide students to state in their own words what they learned about the Plate Tectonics Theory. 2. Using the map or globe used in the previous activity, have students mark the boundaries of the Philippine plate and locate where the islands of the Philippines are. B. Activity Proper 1. Let them do Activity 22.1 in small groups. 2. Let them brainstorm the answers to the questions. a. Class Discussion 1. Have the students present their maps. Follow this up with a discussion of their answers to the Questions. The students should be able to see that earthquake occurrences are more frequent along convergent than on divergent boundaries. They should realize that plate boundaries were determined though the frequencies of the occurrence of earthquakes. ...
Words: 708 - Pages: 3
...Plate Tectonics Melissa Schroeder Columbia College For millions of years, tectonic plates have been determinate of changes in the physical face of the earth, and they continue to do so today. These massive plates move underneath the surfaces of the oceans and the continents, producing earthquakes, volcanoes and uplifts. This paper will discuss the composition, movement and history of tectonic plates, the theory of plate tectonics and its history, and tectonic plates affect the surface of the earth today and will continue to do so in the future. The earth is divided into three main layers: the core, the mantle and the crust. The core is further divided into the solid inner core and the liquid outer core. This layer is mostly iron and nickel and is extremely hot. The mantle is divided into the lower and upper mantle and is composed mostly of iron, magnesium, silicon, and oxygen. The outermost layer, which contains all life on earth, is the crust. This layer is rich in oxygen and silicon as well as aluminum, iron, magnesium, calcium, potassium, and sodium. It is in between the crust and the mantle that we find tectonic plates. The outermost layers of the earth are divided into two categories based on their physical properties. The asthenosphere is the lower of these categories, composed of clastic or flowing mantle. The upper layer is known as the lithosphere and contains both the top, rigid layer of the mantle and the crust. The lithosphere is what makes up the tectonic plates...
Words: 1540 - Pages: 7
...Evaluate how plate tectonics theory helps our understanding of the distribution of seismic and volcanic events. Plate tectonics is a relatively new science. It’s partially explained in the sense that we still don’t know fully about how the plates came together, what they were before they were the seven continents we know today. We already know, or have a theory, about what our world was like a long time ago and so if we already know that the plates can pull and push against each other, then surely there must have been a different set up to the one we have now. There is a theory that we were once a supercontinent called Pangaea that began to break up around 200 million years ago. Using plate tectonics, we can explain, predict and see which type of seismic and volcanic events are related to plate tectonics, using more theories like Pangaea to explain them. Covering our earth’s surface there are seven major plates. These plates cover the inside structure of our earth, which consists of our inner core, our outer core, the mantle and then the crust which is what the plates are made out of. Plate tectonics is the theory of these plates moving along the earth’s lithosphere. The lithosphere is in the upper mantle and the lower crust and is responsible for continental drift. This is also because of the convection current running underneath and pulling and pushing the plates apart and together, causing them to converge and destruct. There are two types of plates, oceanic and continental...
Words: 1940 - Pages: 8
...January 2011 Plate Tectonics and Associated Hazards (25 marks) a) The Philippines are located on the Philippine plate which is largely involved in the tectonic activity of the Pacific Ring of fire where you can find volcanoes and earthquakes which are two primary tectonic hazards, this is due to its location and the fact that numerous trenches are a strong piece of evidence to the presence of the sub-duction of tectonic plates. This makes me think that there is a strong degree to which this area of the Philippines is subject to tectonic hazards. Another piece of evidence supporting a strong chance of tectonic activity is the sheer volume of active faults on the islands compared to the actual land area of the countries, these are were the land has sustained damage over the years of plate movement and the rocks beneath are trapped against each other and creating tension that can be released to create an earthquake of a strong magnitude. Also visible from the image is the location of 5 volcanoes nad if these were to become active most of the countries in the Philippines would be in serious danger from tectonic hazards both primary and secondary like volcanic bombs or lahars. b) Hot spots are points where convection plumes are focusing on a single point beneath the crust as hot magma rises from the super-heated mesosphere into the asthenosphere where it cools and then proceeds to sink back down again. As this magma rises it carries radioactive elements with it and these...
Words: 1056 - Pages: 5
...The Plate Tectonic Theory After many years of research, scientists are now able to get a much greater understanding of how Earth’s geological features are constantly altered through the process of plate tectonics. The theory of plate tectonics explains the reason behind the features of Earth’s surface, which is now fragmented into dozens of lands constantly changed through tectonic behaviors. This was argued for decades up until Wegener’s developed four major plate-tectonics theories. The geological changes we view today can be accredited to global activities demonstrated through the youth of the ocean floor, plate boundaries, and volcanic eruptions. These phenomenon’s play a significant role in the plate tectonic effects in all fields of geology. Contributions and methods began through geologist Alfred Wegener who proposed that 250 millions years ago the supercontinent Pangaea existed, but broke apart through continental drift. Researchers were quick to deny but through Wegener’s remarkable discovery of plant and animal fossils found along the coastline of South America and Africa, it resulted as imperative evidence the continents being previously joined. The convection in the mantle is one of the main driving forces that causes Earth’s core to rise while the cooler mantle rock sinks. This then causes the mid-ocean ridges to pull and sink downward at subduction zones. Most evident plate tectonic forces are most commonly shown along movement in narrow zones. These movements...
Words: 629 - Pages: 3
...From the tallest mountains, all the way to the deepest ocean trenches, plate tectonics explains all the features & movements of earther’s surfaces in both the past & present. Plate tectonics, the theory that earth’s external shell is separated into numerous plates which glide over the rocky internal layer of the core called the mantle. The plates act like a rigid & hard shell compared to earth’s mantle. The lithosphere is what the strong outer layer is referred to as. Developed between the 1950s all the way through to the 1970s, plate tectonics is the up-to-date version of the theory first proposed in 1912 by the scientist Alfred Wegener, called continental drift. Alfred Wegener couldn’t explain how the continents move around the plant but...
Words: 1769 - Pages: 8
...The Creation Of The Floor Karina Decubas SCI/209 Nov 2,2015 Shannon Shoemaker The Creation Of The Ocean Floor Oceanography is the branch of science that studies the ocean and vast amount of topics. I learned the importance of this branch among science. Science has answered many questions and created many theories that goes beyond this science in specific but help to answer more question in other branch of science. Two very important theories are the Continental Drift and the plate tectonics. These theories try to solve the question about the actual position of the continents and how they got there. There are so many terms and information to learn in order to understand these two theories for example plate boundaries, Fault, oceanic floor, volcanoes and more. Plate Boundaries A Plate Boundaries is the location where two plates meet. There are three different plate boundaries. The Divergent plate boundaries are where new crust is generated as the plates pull away from each other. The Divergent plate boundaries occurs along spreading centers where plates are moving apart and the new crust is created by magma pushing up from mantle. A good example is the Mid-Atlantic ridge. The rate of spreading along the Mid-Atlantic ridge averages 2.5 centimeters per year. Convergent Boundaries is where the crust is destroyed as one plate dives under another. The Size of the earth has not change significantly during the past 600 millions years. The...
Words: 885 - Pages: 4
...a common subject to anyone outside of a scientific or marine biology lab. The purpose of this paper is to identify plate boundaries. Compare and contrast ideas behind plate tectonics and the theory of the continental drift. There are many types of plate boundaries. Each one is unique in its own way. Below three of the primary types are described in detail. There are several natural events that occur as a direct result of plate boundary interaction. To properly understand the what and how of plate boundaries one must first know what they are. According to Annenberg Foundation (2014), “The border between two tectonic plates is called a boundary. All the tectonic plates are constantly moving — very slowly — around the planet, but in many different directions. Some are moving toward each other, some are moving apart, and some are sliding past each other” (para. 3). Divergent, convergent, and transform are the three primary types of plates. According to "Plate Tectonics" (2010) “A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water. Frequent earthquakes strike along the rift. Beneath the rift, magma—molten rock—rises from the mantle” (divergent boundary). According to "Plate Tectonics" (2010), “When two plates come together, it is known as a convergent boundary. The impact of the...
Words: 816 - Pages: 4
...With reference to particular examples, suggest why the impacts of tectonic hazards vary from place to place Tectonic hazards are natural events occurring due to movements or deformations of the earth’s crust with the potential to cause damage to lives and properties. E.g. earthquake and volcanic activities. The impact caused by tectonic hazards on lives and properties are mainly determined by physical factors, vulnerability factors and affected region’s capacity to cope. These factors are parts of the risk equation, which is used to measure the level of hazard risk of an area. Which I will be using it to explain why the impacts of tectonic hazards vary from place to place. One of the main reason why some place suffers more than the others is the global distribution of earthquakes, this is due to the margins of tectonic plates. It is commonly known that earthquakes happen on the plate boundaries. However, at some plate margins, earthquakes are more destructive and frequents, for example, Eurasian plate and Pacific plate, where Pacific plate sinks under the Eurasian plate. The impacts of tectonic hazards seem to vary significantly in countries with different economic development. This is evident in 2010, with an earthquake reached magnitude of 7.1 on the Richter scale, struck Port-au-Prince, the capital of Haiti, with 316000 people being killed. Whereas in 2011, an earthquake reached magnitude of 9.0 on the Richter scale struck Japan caused just 20896 deaths. The significant...
Words: 787 - Pages: 4
