Tsunami Warning Systems

Front

Lithosphere Noun

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[lith-uh-sfeer]

Back

Lithosphere

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The rigid outer part of the earth, consisting of the crust and upper mantle, which is broken into tectonic plates.

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Example: This diagram shows the lithosphere as the solid, rocky outer layer of the Earth, which includes the crust and upper mantle.

Front

Asthenosphere Noun

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[as-then-uh-sfeer]

Back

Asthenosphere

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The soft, slowly flowing layer of the Earth's upper mantle just below the lithosphere, on which tectonic plates float.

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Example: This diagram shows the Asthenosphere as the 'plastic' layer of the upper mantle, located directly beneath the 'rigid' Lithosphere, upon which tectonic plates move.

Front

Plate Tectonics Noun

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[pleyt tek-ton-iks]

Back

Plate Tectonics

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The scientific theory that Earth's outer shell is divided into several plates that glide over the mantle's rocky inner layer.

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Example: This diagram shows one of Earth's tectonic plates sliding underneath another, a process called subduction, which can create mountains on the surface.

Front

Convergent Boundary Noun

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[kuhn-vur-juhnt boun-dree]

Back

Convergent Boundary

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A location where two tectonic plates are actively moving toward each other, resulting in a collision or one sliding beneath another.

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Example: This diagram shows two tectonic plates colliding, with the denser oceanic crust sliding under the continental crust, forming a trench.

Front

Subduction Zone Noun

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[suhb-duhk-shuhn zohn]

Back

Subduction Zone

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A type of convergent boundary where one tectonic plate is forced to slide beneath another plate into the Earth's mantle.

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Example: This diagram shows one tectonic plate sliding under another, a process called subduction. This often creates volcanoes as the sinking plate melts.

Front

Divergent Boundary Noun

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[dahy-vur-juhnt boun-dree]

Back

Divergent Boundary

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A location where two tectonic plates are moving apart from each other, often creating new crust at mid-ocean ridges.

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Example: This diagram shows two of Earth's plates (oceanic crust) moving away from each other, allowing hot magma to rise and create new seafloor.

Front

Transform Boundary Noun

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[trans-fawrm boun-dree]

Back

Transform Boundary

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A location where two tectonic plates slide past one another horizontally, often causing earthquakes along the resulting fault line.

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Example: This diagram shows a transform boundary, where two of Earth's plates slide horizontally past one another, often causing earthquakes along the fault line.

Front

Focus Noun

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[foh-kuhs]

Back

Focus

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The point deep within the Earth's crust where rocks rupture to generate an earthquake, also known as the hypocenter.

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Example: This diagram shows an earthquake's focus (labeled 'Hypocenter'), which is the point underground where the earthquake begins along a fault line.

Front

Epicenter Noun

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[ep-i-sen-ter]

Back

Epicenter

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The point on the Earth's surface located directly above the focus, or origin point, of an earthquake.

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Example: This diagram shows that the epicenter is the point on the Earth's surface located directly above the hypocenter, where an earthquake begins underground.

Front

Tsunami Noun

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[tsoo-nah-mee]

Back

Tsunami

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A series of powerful ocean waves caused by a large, sudden displacement of water, typically from an undersea earthquake.

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Example: This diagram shows that as a tsunami wave moves into shallower water near the coast, its speed decreases, but its height increases dramatically.