Diastrophism is deformation of earth’s crust, caused by folding and faulting. Convergent plate boundaries are formed through diastrophism. A convergent boundary (or a destructive plate boundary) is formed when two or more tectonic, lithospheric plates collide. There are two types of plates: oceanic (more dense) and continental (less dense). If two oceanic plates collide, subduction will occur. Subduction refers to the movement of one plate, sliding underneath another plate. The plate that is pushed down is consumed by the magma in the internal structure of the earth. When this happens, there will be a large, deep underwater trench where the subduction occurred (Mariana’s trench is an example of this). The plate that is consumed by magma causes …show more content…
a magma plume (a build-up of magma) that upwells and pushes through the crust. This upwards movement can cause arcs of volcanic islands to form (Indonesian Islands are an example). Another possibility is the collision of an oceanic plate and a continental plate. The result is somewhat similar to the previously explained example. Subduction will occur and another deep sea trench will be formed, but this time near the continent. Tall, composite volcanoes will form along the coast of the continent (Mount Garibaldi is one of these volcanoes that was formed due to subduction). Both subduction boundary plate interactions are sites of deadly earthquakes, very high on the Richter scale. These earthquakes would happen near the ocean (an oceanic plate is always involved in subduction), so a massive tsunami would most likely be formed if the earthquake is powerful. For the last scenario, two continental plates could collide. This is also sometimes called convergence. The two plates will crumple (fold) together and cause orogeny (uplift), instead of subduction. These plates then mould together to become one large plate. This usually causes incredibly tall mountains to form (The Himalayas were formed this way). There are also faults (cracks in the Earth) that run perpendicular to the boundary. Near the location of convergence there can be many strong, deep earthquakes, and little earthquakes at the nearby faults. These faults are called transform faults, or a conservative plate boundary.
A transform fault is a fault in the Earth that is connected to a tectonic plate or another fault in the earth. Earthquakes in these faults are caused by two plates sliding past each other, laterally. They are called conservative plate boundaries because nothing in the lithosphere is destroyed or created. Also, there is no volcanism or orogeny, but there are visible cracks in the surface of the crust. Transform faults can also be found near mid-oceanic ridges (caused by an upwell of magma). Transform faults would be classified as a strike-slip fault movement, and the only type of strike-slip fault that is classified as a plate boundary. Because these faults are connected to other faults or plates, they can only grow, shrink or stay the same size. Transform faults will grow if they are connected to an upper block of a subduction zone and a spreading centre (the sea floor spreading into mid-oceanic ridge, caused by magma upwells). They will also increase in length if they are linked to two upper blocks of a subduction zone, when they move the fault could grow. In most other situations, the faults stay the same length. If the transform fault is in between two ridges, the equal pulling of the ridges could neutralize the possible size change. If a subduction plate and a ridge are linked, there will be no change because new sea floor is being created while some is being swallowed, canceling out potential …show more content…
length variability. Also, if two upper subduction plates are linked, the move parallel to each other, adding nothing new to the Lithosphere. Finally, in rare moments, transform faults can shrink in length. If two subduction plates are linked (descending ones), the fault will shorten in length until it eventually completely disappears. A rift valley is a mostly straight lowland, found between mountain ranges or highlands.
A rift valley is formed on a divergent plate boundary. Divergence of plates happens because of slab pull (plates being pulled apart due to asthenospheric convection). When two plates are pulled apart, a ridge forms, and low-silica magma comes from inside the Earth to make a new crust (this is called plate formation). Rifts can occur at any location, of any elevation and on both types of plates. Rifts usually form vast valleys around the World (a commonly used example is the African Rift Valley, and it is still currently active). There are often large, incredibly deep lakes found in rift valleys (the deepest lake in the world, Lake Baikal is part of an active rift valley). Rift valleys have mostly shallow earthquakes, not devastating at all. Cracks in the valley with lava flowing out of them can also be found (volcanic fissures), along with cinder cone volcanoes. In Garibaldi Provincial Park, in British Columbia there is a cinder cone volcano, with cinder flats surrounding it, similar volcanoes can be found in rift
valleys.
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...
The west coast of North America has been tectonically and volcanically active for billions of years. The Sierra Nevada Mountains in eastern California were born of volcanoes, and magma has been erupting in the Long Valley to the east of the mountains for over three million years (Bailey, et. al., 1989). However, the climactic eruption of the region occurred relatively recently in the region's geologic history. About 760,000 years ago, a huge explosion of magma warped the Eastern Sierra into the landscape that exists today. The eruption depleted a massive magma chamber below the earth's surface so that the ceiling of the chamber imploded, forming what is now known as the Long Valley caldera. The caldera is at the eastern base of the Sierra Nevada Mountains, about 50 km northwest of the town of Bishop, and 30 km south of Mono Lake (Bailey, 1976).
When the plates mash together on a convergent boundary, they can create an earthquake. A place with a convergent boundary is New Zealand. When the plates pull apart, a divergent boundary, they create a hole in the ocean that causes molten lava to rush up and it causes a volcano to form. A place with a divergent boundary is Iceland. With about 130 volcanoes all together, it has the most volcanoes of any country in the world and is on two tectonic plates. Santorini is currently in an area of earth where the African and Eurasian plate meet, and Atlantis disappeared with a rumble that could have come from a volcano or an
The San Andreas Fault Line, first identified in 1895 by Professor Andrew Lawson of UC Berkeley, is an 800-mile fracture in the Earth’s surface, stretching from the Gulf of California to San Francisco, and is one of the longest faults in the world. It forms the boundary between the Pacific Plate and the North American Plate, with a complex network of smaller faults branching off the main San Andreas line which are responsible for a majority of the areas earthquakes.
...tectonic movement of the plates, the stress forms along the fault and ultimately releases as an earthquake. On the pacific plate, Transform boundary along with the San Andreas fault. Transform-fault boundaries is when two plates that slide horizontally past another. Transform boundaries are usually found on ocean floor, but a few occur on the land. San Andreas fault zone is a transform fault, which connects East Pacific rise, in the south a divergent boundary, with South Gorda-Juan de Fuca-Explorer Ridge, yet another divergent boundary to the North. Ultimately because it’s a transform boundary, convergent boundary is strike-slipping past each of the plates in order to release pressure. As the San Andreas Fault is prime transform boundary between the North American Plate and the Pacific Plate, the Hayward Fault assumes a share of the total motion between the plates.
This is because all of them move the crust in different ways. Weather it be a few tenths of degrees or multiple degrees, the plates are always moving. Sometimes when these plates collide, things like volcanoes can come to form. The boundaries can make things like: folded mountain ranges, volcanoes, earthquakes, trenches, mid ocean ridges, and rift valleys. Convergent boundaries are when the plates collide into each other.
Additionally, this earthquake occurred on a thrust fault. This fault was a subduction zone slip which occurred primarily beneath the ocean were the Pacific plate plunges underneath the North American plate. This sudden upward movement of the sea floor along the rupturing fault generated a massive tsunami. This vertical deformation
Super volcanoes are formed when magma rises from the mantle to create a scorching reservoir in the Earth's
The earth is split into four layers, inner and outer core, the mantle and crust. The top of the mantle and crust make up what is like the skin of our earth (see source 2). The skin is split up like a puzzle and we call these puzzle pieces’ tectonic plates (see source 1). These plates are constantly moving and the plate boundaries (edges of the plates) move and slide past one another. Sometimes as the plates move the plate boundaries become stuck. Pressure builds up in the stuck area over time and eventually breaks. This is why earthquakes occur due to the sudden movement of the plate sliding and breaking creating a fault line to go off. The fault line is the line on which the
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.
Body The entire San Andreas fault system is more than 800 miles long and extends to depths of at least 10 miles within the Earth. The fault is a complex zone of crushed and broken rock from a few hundred feet to a mile wide. Many smaller faults branch from and join the San Andreas fault zone. The Pacific plate is moving northwest in relation to the North American plate, and it is believed that the total displacement along the fault since its formation more than 30 million years ago has been about 350 mi. Movement along the fault causes earthquakes; several thousand occur annually.
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 result in injuries and people getting killed, wildlife getting disrupted as well as humans. An earthquake can affect the earth as it’s easier to let the lava come out of the earth. Tsunamis- Can cause financial problems such as home loss, job loss which will then result in being homeless, loss of crops and food supplies which causes a lot of harm to us ‘humans’. A tsunami is a series of waves that send surges of water that can travel thousands of miles.
A mountain is the most basic result of two plates colliding. A mountain is formed when two continental plates collide, the plates crunch and fold the rock at the boundary, lifting it up and forming mountains and mountain ranges. According to the science textbook on page 206 lines 19-22 the text states “Two plates carrying continental crust can also collide. Then, neither piece of crust is dense enough to sink far into the mantle. Instead, the collision squeezes the crust into high mountain ranges.” The second possible landform that is caused by a convergent boundary is a deep ocean trench. A deep ocean trench is an underwater subduction zone involving two oceanic plates, or a continental and oceanic plate. A subduction zone is where two plates collide and the older, denser, and colder tectonic plate goes under (or subducts to) the newer, less dense, warmer tectonic plate. The plate which had more time to cool subducts under the hotter plate because in a colder substance the molecules are closer together which makes the plates substance more dense which causes the plate to sink. Whereas in a warmer substance, the molecules that make up the object are farther apart and are
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).