Ocean Topography

Front

Topography Noun

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[tuh-pog-ruh-fee]

Back

Topography

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The study of the elevation, shape, and arrangement of natural and artificial features on the surface of the land.

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Example: This diagram shows how a 3D landform, like a hill, is translated into a 2D topographic map using contour lines that connect points of equal elevation.

Front

Sonar Noun

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[soh-nahr]

Back

Sonar

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A technology that uses sound propagation to navigate, communicate with, or detect objects on or under the water's surface.

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Example: A ship sends out a sound wave from a sender/receiver. The wave travels down, bounces off an object on the seabed, and returns as a reflected wave.

Front

Echo Sounding Noun

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[ek-oh sound-ing]

Back

Echo Sounding

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The process of using sonar to measure water depth by timing a sound pulse's journey to the seafloor and back.

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Example: A ship sends a sound pulse to the ocean floor, and the time it takes for the returning echo to be detected is used to calculate the water's depth.

Front

Oceanic Crust Noun

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[oh-shee-an-ik krust]

Back

Oceanic Crust

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The relatively thin, dense layer of Earth's crust that forms the foundation of the ocean basins.

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Example: This diagram shows new, thinner oceanic crust forming at a mid-ocean ridge as magma rises, cools, and pushes older crust aside.

Front

Continental Crust Noun

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[kon-tuh-nen-tl krust]

Back

Continental Crust

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The thick, less dense layer of Earth's crust that forms the large landmasses and their shallow continental shelves.

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Example: This diagram shows the continental crust, the thick layer of rock that forms the Earth's landmasses, positioned above the denser oceanic crust.

Front

Convection Currents Noun

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[kuhn-vek-shuhn kur-ents]

Back

Convection Currents

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The circular movement within a fluid, caused by temperature differences, that drives the motion of tectonic plates in the mantle.

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Example: This diagram shows how heat from the Earth's core causes material in the mantle to rise, cool, and sink, creating circular convection currents.

Front

Convergent Boundary Noun

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[kuhn-vur-juhnt boun-dree]

Back

Convergent Boundary

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A tectonic boundary where two plates are moving toward each other, often resulting in subduction or mountain building.

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Example: This diagram shows a dense oceanic plate colliding with and sliding under a continental plate, a process called subduction, forming a deep ocean trench.

Front

Divergent Boundary Noun

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[dahy-vur-juhnt boun-dree]

Back

Divergent Boundary

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A tectonic boundary where two plates are moving apart, allowing magma to rise and form new crust.

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Example: This diagram shows two oceanic crust plates pulling apart, allowing magma from below to rise and create new seafloor, forming a mid-ocean ridge.

Front

Transform Boundary Noun

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[trans-fawrm boun-dree]

Back

Transform Boundary

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A tectonic boundary where two plates slide horizontally past each other, often causing earthquakes along fault lines.

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Example: This diagram shows a transform boundary where two tectonic plates slide horizontally past each other, one carrying an ocean and the other carrying a continent.

Front

Ocean Basin Noun

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[oh-shuhn bey-sin]

Back

Ocean Basin

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A large geologic depression below sea level, located between the continental margins, that holds the water of an ocean.

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Example: This diagram shows a cross-section of an ocean basin, labeling its main topographical features like the continental shelf, abyssal plain, and ocean trench.