Understanding Plate Boundaries

Front

outer layer Noun

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[ow-ter ley-er]

Back

outer layer

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Earth's outermost layer, which is made of hard, solid rock and is divided into sections called plates.

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Example: The crust is Earth's outermost layer, shown here as a thin, solid shell.

Front

plate Noun

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[pleyt]

Back

plate

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A large section of Earth's outer layer that is in constant, slow motion over the soft, solid mantle.

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Example: The image shows tectonic plates moving over the mantle, illustrating plate boundaries.

Front

mantle Noun

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[man-tl]

Back

mantle

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The layer of soft, solid rock located beneath Earth's plates, upon which the tectonic plates slowly move.

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Example: The mantle is shown beneath Earth's crust, where tectonic plates move.

Front

plate boundary Noun

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[pleyt boun-dree]

Back

plate boundary

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The specific location on Earth's surface where the edges of two different tectonic plates meet each other.

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Example: Two tectonic plates collide, forming mountains at their boundary.

Front

convergent Adjective

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[kuhn-vur-juhnt]

Back

convergent

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A type of plate boundary where two tectonic plates are moving directly toward one another, often resulting in collision.

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Example: The image shows a convergent boundary where oceanic crust moves toward continental crust, forming a trench.

Front

trench Noun

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[trench]

Back

trench

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A long, deep depression on the ocean floor formed where one tectonic plate sinks underneath another at a convergent boundary.

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Example: The image shows a trench formed where the oceanic crust sinks below the continental crust at a convergent boundary.

Front

divergent Adjective

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[dahy-vur-juhnt]

Back

divergent

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A type of plate boundary where two tectonic plates are moving away from each other, creating a gap.

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Example: Two oceanic plates move apart, allowing magma to rise and form new crust.

Front

mid-ocean ridge Noun

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[mid-oh-shuhn rij]

Back

mid-ocean ridge

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An underwater mountain range formed by magma rising from the mantle at a divergent plate boundary, creating new seafloor.

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Example: Magma rises at a divergent boundary, forming new oceanic crust and creating a mid-ocean ridge.

Front

earthquake Noun

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[urth-kweyk]

Back

earthquake

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A sudden shaking of the ground caused by the movement of rock beneath Earth's surface, often at plate boundaries.

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Example: Arrows show how tectonic plates move, causing an earthquake.

Front

volcanic activity Noun

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[vol-kan-ik ak-tiv-i-tee]

Back

volcanic activity

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The process of magma, gas, and ash erupting from an opening in Earth's crust, often near plate boundaries.

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Example: This diagram shows magma erupting from a volcano, with labels for ash cloud, lava flow, and magma chamber.