Earth Science Flashcards

Flashcards about Earth Spheres, Earth's Interior, Faults, Plate Tectonics, Mountains, Subduction Zones, Volcanoes, Continental Drift, Earthquakes, and Tsunamis.

What is the lithosphere?

Solid part of the earth, including rocks and minerals.

What is the hydrosphere?

Liquid part of the earth, including oceans and rivers.

What is the atmosphere?

Gaseous part of the earth, including oxygen and nitrogen.

What is oceanic crust?

Crust below the oceans.

What is continental crust?

Crust that is made of land.

What is the mantle?

Liquid layer of the Earth made of melted rock.

What is the Asthenosphere?

Part of the mantle with convection currents.

What is the Outer Core?

Liquid layer of the Earth made of iron and nickel.

What is the Inner Core?

Solid layer of the Earth made of iron and nickel.

What are faults?

Large fractures or breaks in the Earth's crust.

What happens in Normal Faults?

Rock moves down due to extension.

What happens in Reverse Faults?

Rock moves upward due to shortening.

What happens in Strike-Slip Faults?

Rocks slide past one another in opposite directions.

How are mountains formed through subduction (continental-continental)?

When 2 continental plates come together; plates push up and form mountains.

What happens at Transform Fault Boundaries?

Plates slide past each other moving in opposite directions, causing earthquakes/tsunamis.

What is a Deep-Sea Trench?

A depression (hole) in the ocean floor at a subduction zone.

How are Volcanic Island Chains formed (oceanic-oceanic subduction)?

When 2 oceanic plates meet and one goes under the other, forming volcanic islands.

What happens in Subduction Zones?

When one plate goes under another plate; the more dense (heavier) plate goes under.

How is a Volcanic Arc formed (oceanic-continental subduction)?

More dense (heavier) oceanic crust goes under the less dense continental crust, creating volcanoes and trenches.

What is the difference between Oceanic and Continental plate density?

Oceanic plates (dense) sink underneath continental crust, while continental plates (less dense) are lighter.

What is a Plate Boundary?

Border between 2 plates.

What occurs at a Divergent Boundary?

Plates move apart, causing sea-floor spreading, mid-ocean ridges and rift valleys

What occurs at a Convergent Boundary?

Plates come together, causing mountains, subduction zones, deep-sea trenches, and volcanic/island arcs.

What occurs at a Transform Boundary?

Plates slide past each other, causing faults, earthquakes, and tsunamis.

How do Convection Currents affect plate movement?

Convection cells in the mantle move the plates; hot, less dense magma rises, cools at the surface and sinks back down.

What is a Seismograph?

Instrument that measures earthquake waves.

What is a P-Wave (primary wave)?

Fastest earthquake wave, that moves back and forth

What is a S-Wave (secondary wave)?

Slower earthquake wave, that moves up and down

What is a L-Wave (surface wave)?

Most dangerous earthquake wave, that moves back and forth AND side to side.

What are Tsunamis?

Large ocean waves caused by an earthquake under the ocean.

What is the Theory of Plate Tectonics?

The theory that Earth's crust is broken up into sections/pieces (plates) that move on top of the liquid mantle (asthenosphere).

What are the major tectonic plates?

Eurasian, African, Australian-Indian, North American, Pacific, Antarctic and South American.

How are islands formed from Hot Spots?

Mantle is really hot and magma is forced up to the surface, creating islands.

What is the Focus of an earthquake?

Point under the earth's surface where an earthquake starts.

What is the Epicenter of an earthquake?

Place on earth's surface directly above the focus of an earthquake.

What is Continental Drift?

Alfred Wegener's theory that the continents were once a single supercontinent called Pangaea.

What is the evidence for Continental Drift?

Continents fit together like a puzzle, similar fossils on different coastlines, and matching rock types on different continents.

What are Volcanoes?

Opening in the earth that erupts gases, ash and lava, caused by plate movement along boundaries.

What is Magma?

Melted rock under the surface (INSIDE).

What is Lava?

Melted rock above the surface (OUTSIDE).

What is a Shield Volcano?

Volcanic cone made up of layers of hardened lava.

What is a Cinder Cone Volcano?

Volcanic cone made up of rock particles, dust, and ash.

What is a Composite Volcano?

Volcanic cone made up of alternating layers of lava and rock particles.

What are Magnetic Reversals (Paleomagnetism)?

Youngest crust is in the center, older as you go out; Earth's magnetic poles reverse from North to South.

What is a Mid-Ocean Ridge?

A mountain under the ocean, forming where oceanic plates separate.

What occurs at Divergent Boundaries?

Plates move apart.

What is Seafloor Spreading?

Process by which new oceanic crust is created; two oceanic plates move apart and magma comes up.

What is a Rift Valley?

When continental plates pull apart, they form rift valleys, volcanoes and new land.

What occurs at Convergent Boundaries?

Plates come together.