Alfred could not explain how the huge masses of land could have moved so far. The major means for the lithospheric plates to float on the asthenosphere comes from the process of convection in the mantle of the Earth. Heat from the outer core rises in the mantle and “melts” the upper part, which is called the asthenosphere. The plates of the lithosphere move in three main ways. There are divergent boundaries where the plates are moving away from each other and new land is formed as magma is released from inside the mantle.
Research into the theory of plate tectonics first began around 1920. This research was spearheaded by Alfred Wegner, a German meteorologist and geophysicist. His work presented the theory that today’s continents once were joined as one to form a huge supercontinent commonly referred to as Pangaea today. Wegner’s theory stated that the super continent broke up and the pieces (today’s continents) drifted over time into their current positions, he called this “Continental Drift”. Wegener's theory also provided an alternate explanation for the formation of mountains (orogenesis).
Even though the coastlines didn’t match perfectly (maybe due to erosion/weathering), he later found that the continental shelves matched more closely which matched the theory that those continents were once together. The strongest evidence for continental movement is the study of paleomagnetism. The study of the intensity and orientation of the Earths magnetic field is preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time. A study of the ocean floors have demonstrated that the orientation of the earths
Plate tectonics was first suggested as a theory by the geologist Alfred Wegener in 1915 when he proposed the concept of continental drift. Back in the geological past, what is now South America, Africa, Australasia and Antarctica fitted together into a supercontinent known as Gondwanaland; with North America, Europe and Asia fitting into another supercontinent known as Laurasia. (OCR AS/A2 Geology, Mugglestone et al, 2008). These were once believed to be joined to form one major central global landmass known as Pangaea (Introducing Geology, Graham Park). But now due to the global distribution of these major plates it has been proposed by Wegener and his successors that convection currents in the mantle are the cause of the movement of plates.
GCSE Geography Explain the process which leads to the development of one landform at a destructive plate boundary (6 marks). A destructive plate margin is an area where two plates are moving towards each other. The point where the two plates meet is called the subduction zone, where one plate is forced down under the other into the mantle. The subducted plate is cooler and denser than the surrounding mantle and gravity pulls it down. Along the coast of south America, the Nazca plate is moving towards the south American plate.
I will explain the physical geography of the surrounding water and land. When understanding in some detail the geography behind the waves at Maverick there are many complicated things to take into consideration; for instance tide measurements, wind speed, isobar charts, atmospheric weather maps, etc. In the book, “Maverick’s: The Story of Big Wave Surfing,” the author Matt Warshaw explains that the Maverick’s begin as an atmospheric dimple in the North Pacific (Warshaw 2000). In which it grows into a low-pressure system, the corkscrewing union between an arctic air mass and a warmer ocean-heated air mass (Warshaw 2000, p. 43). Then the low-pressure system matures along the west-to-east atmospheric highway also known as jet stream; then a storm will move slowly along the jet stream that would produce the large waves (Warshaw 2000).
(Some geologists argue that this portion of the Eurasian Plate is actually a fragment of the North American Plate called the Okhotsk microplate.) A part of the subduction zone measuring approximately 190 miles (300 km) long by 95 miles (150 km) wide lurched as much as 164 feet (50 metres) to the east-southeast and thrust upward about 33 feet (10 metres). (“Japan Earthquake and Tsunami of 2011, 1”) A series of extremely destructive tsunami waves followed the 9.0 earthquake along with the dozens of foreshocks and aftershocks that came with it. The city of Sendai, its surrounding area and airport were pounded by a wave
Ricardo Perez Historical Processes of Puerto Rico San Fermin Earthquake of 1918 The geological position of Puerto Rico raises a concern for earthquakes in the modern day. The island is located very close to the junction of the Caribbean and North American tectonic plates. A combination of seismic and volcanic activity created the Caribbean islands as we know them today. All of the Caribbean islands, with the exception of Barbados, were created from the fierce volcanic activity of the millions of years ago during the Antillean Revolution. Violent movements of the plates in the Post-Glacial era created the Puerto Rican Trench, nearly 24,000 feet deep, which is the deepest point in the Atlantic Ocean.
J. Subbiondo © 2004The CrustThe outer layer of the Earth is called the crust. It is made up of rock that floated to the surface when the Earth was formed. It is not a continuous layer, but is made up of large masses called tectonic plates.These plates drift slowly across the Earth's surface (tectonic means moving).The movement of these plates creates mountains and valleys.At weak points in the crust, it causes volcanic eruptions. And when plates bump into each other, earthquakes occur -- emitting shock waves or vibrations called seismic waves. The crust is the Earth's coldest layer.
------------------------------------------------- Submarine earthquake From Wikipedia, the free encyclopedia Tectonic plate boundaries, showing the plate movement direction and magnitude of motion. Tectonic plate boundaries Convergent plate boundary trench formation and dynamics Convergent plate boundary: Mariana trench Plate Tectonics Transform plate boundary: San Andreas Fault Divergent plate boundary: Mid-Atlantic Ridge Divergent plate boundary: Mid-Atlantic Ridge A submarine, undersea, or underwater earthquake is an earthquakethat occurs underwater at the bottom of a body of water, especially anocean. They are the leading cause of tsunamis. The magnitude can be measured scientifically by the use of either the Richter scale or the Mercalli scale. [1] Understanding plate tectonics helps to explain the cause of submarine earthquakes.