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Define convection. How does it result in tectonic plate movement?

What are the 3 types of plate boundaries? Describe each.

Explain the scientific evidence that supports continental drift.

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Learn what tectonic plates and why they move. Tectonic plates form boundaries that can be convergent, divergent or transform. Our video shows all 3 types. Watch now.

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The most popular scale of energy evaluation in earthquakes is the local scale of the Richter magnitude. Thus, the increase is a degree of magnitude of the 32-fold increase in the released seismic energy. An earthquake of magnitude 2 is subtle until the magnitude 7 is the lower limit of destructive earthquakes that cover large areas.

1 (undetectable) - only indicated by special devices;
2 (very low) - only felt by very sensitive pets and people in the upper floors of tall buildings;
3 (low) - feels only in some buildings, like the vibration of a truck;
4 (moderate) - the earthquake is felt by many people; It is possible to balance open windows and doors;
5 (strong note) - shaking of hanging objects, noise in construction, window breakage, dust blowing;
6 (strong) - slight damage to construction of buildings, cracks in plaster, etc.;
7 (very strong) - significant damage to buildings; Cracks in the plaster and breaking of individual pieces, thin cracks on the walls, cracks of chimneys; Cracks in the foundations;
8 (destructive) - destruction in buildings: large cracks on the walls, falling cornices and chimneys. Landslides and cracks up to a few centimeters on mountain slopes;
9 (devastating) - burglary of some buildings, falling walls, dividing walls and roofs. Landslides, collapse and falling debris into the mountains. The rate of increase of the cracks can be up to 2 cm/s;
10 (destructive) - collapse of many buildings; In others - serious damage. Cracks in the ground up to 1 m wide, avalanches, landslides. Through the accumulation of rubble, lakes can form in the river valleys;
11 (catastrophic) - numerous cracks on the surface of the earth, large avalanches in the mountains. Mass destruction of buildings;
12 (total) - changes of the relief on a large scale. Huge avalanches and burglaries. Total destruction of buildings and facilities.

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The most popular scale of energy evaluation in earthquakes is the local scale of the Richter magnitude. Thus, the increase is a degree of magnitude of the 32-fold increase in the released seismic energy. An earthquake of magnitude 2 is subtle until the magnitude 7 is the lower limit of destructive earthquakes that cover large areas.

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Earth looked very different long ago. Search for addresses across 750 million years of Earth's history.

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The Hidden Worlds of the National Parks - Google Arts & Culture

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Plate Boundaries, Earthquakes and Volcanoes Flashcards | Quizlet

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Study with Quizlet and memorize flashcards terms like Stress, Compression, Tension and more.

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Evidence of Plate Motions - Geology (U.S. National Park Service)

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Modified from “Beauty from the Beast: Plate Tectonics and the Landscapes of the Pacific Northwest,” by Robert J. Lillie, Wells Creek Publishers, 92 pp., 2015, www.amazon.com/dp/1512211893).

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Plate Tectonics Seafloor Spreading Activity Map the Ocean Floor

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Students learn how ocean depth is measured and discover the mid-ocean ridge as they chart the Atlantic seafloor.NGSS Standards: Earth Science MS-ESS2-1 and MS-ESS2-2NGSS Science & Engineering Practice: Analyzing and interpreting data NGSS Science & Engineering Practice: Using mathematics an.…

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hese maps are part of "Discovering Plate Boundaries," a classroom exercise developed by Dale S. Sawyer at Rice University (dale@rice.edu).Additional information about this exercise can be found here..

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Silfra Fissure - The World's Clearest Water

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Divergent Boundary

A divergent boundary (or spreading boundary) occurs where two plates move apart. Magma, or molten rock, rises from Earth's interior to fill the gap.

Earth's longest mountain range is an underwater volcanic chain 40,000 miles (65,000 km) long. Called the mid-ocean ridge, it runs down the middle of the Atlantic Ocean (surfacing at Iceland), around Africa, through the Indian Ocean, between Australia and Antarctica, and north through the Pacific Ocean. Along the top of this ocean ridge is a deep crack, called a rift valley. Here, magma wells up from Earth's interior. Cooled by the sea, it solidifies into rock, creating new ocean floor.

The mid-ocean ridge is where plates are moving apart-and therefore creating new sea floor-at a rate of about 1 inch (2.5 cm) per year. In the East Pacific Rise, the rate can be as high as 6 inches (15 cm) per year.

Sea-floor spreading at divergent boundaries continually pushes out new crust. But because of the subduction of oceanic crust at convergent boundaries, the size of Earth remains the same.

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A divergent boundary (or spreading boundary) occurs where two plates move apart. Magma, or molten rock, rises from Earth's interior to fill the gap. Earth's longest mountain range is an underwater volcanic chain 40,000 miles (65,000 km) long.

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Earth Science, Geology

Image

Image by Naeblys

In some ways, Earth resembles a giant jigsaw puzzle. That is because its outer surface is composed of about 20 tectonic plates, enormous sections of Earth's crust that roughly fit together and meet at places called plate boundaries.

Plate boundaries are important because they are often associated with earthquakes and volcanoes. When Earth's tectonic plates grind past one another, enormous amounts of energy can be released in the form of earthquakes. Volcanoes are also often found near plate boundaries because molten rock from deep within Earth-called magma-can travel upward at these intersections between plates.

There are many different types of plate boundaries. For example, sections of Earth's crust can come together and collide (a "convergent" plate boundary), spread apart (a "divergent" plate boundary), or slide past one another (a "transform" plate boundary). Each of these types of plate boundaries is associated with different geological features.

Typically, a convergent plate boundary-such as the one between the Indian Plate and the Eurasian Plate-forms towering mountain ranges, like the Himalaya, as Earth's crust is crumpled and pushed upward. In some cases, however, a convergent plate boundary can result in one tectonic plate diving underneath another. This process, called "subduction," involves an older, denser tectonic plate being forced deep into the planet underneath a younger, less-dense tectonic plate. When this process occurs in the ocean, an trench">ocean trench can form. These trenches are some of the deepest places in the ocean, and they are often the sites of strong earthquakes.

When subduction occurs, a chain of volcanoes often develops near the convergent plate boundary. One such chain of volcanoes can be found on the western coast of the United States, spanning across the states of California, Oregon, and Washington.

A divergent plate boundary often forms a mountain chain known as a ridge. This feature forms as magma escapes into the space between the spreading tectonic plates. One example of a ridge is the Mid-Atlantic Ridge, an undersea chain of mountains that formed as two pairs of tectonic plates spread apart: the North American Plate and the Eurasian Plate in the north, and the South American Plate and the African Plate in the south. Because ocean ridges are found underwater, often at great depths, they can be hard to study. In fact, scientists know more about the surfaces of some of the other planets in our solar system than they do about ocean ridges.

A transform plate boundary occurs when two plates slide past each other, horizontally. A well-known transform plate boundary is the San Andreas Fault, which is responsible for many of California's earthquakes.

A single tectonic plate can have multiple types of plate boundaries with the other plates that surround it. For instance, the Pacific Plate, one of Earth's largest tectonic plates, includes convergent, divergent, and transform plate boundaries.

Director

Author

National Geographic Society

Production Managers

Program Specialists

Last Updated

November 29, 2023

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Earth's tectonic plates fit together in a jigsaw puzzle of plate boundaries.