Earth Mechanics

Question 1

Continental Crust

Answer 1

Crust that defines the landmasses (continents) on Earth. Usually older and less dense than the oceanic crust.

Question 2

Oceanic Crust

Answer 2

The crust that supports the world’s oceans. It is relatively thinner and denser than continental crust.

Question 3

Mantle

Answer 3

The mantle is the semi-solid, thickest layer between the crust and the core. The mantle contains iron and nickel, whose flow produces the Earth’s magnetic field.

Question 4

Outer Core

Answer 4

The outer core is the upper half of the core region and the only liquid layer, also composed of iron and nickel.

Question 5

Inner Core

Answer 5

The inner core is the hottest layer, found at the very center of the Earth. Pressures here are so extreme that it is solid, and its temperatures reach 5200 degrees celsius, equivalent to temperatures on the surface of the sun.

Question 6

Magma

Answer 6

Magma is molten rock located under the Earth’s surface.

Question 7

Lava

Answer 7

Lava is the term for magma flowing on the Earth’s surface.

Question 8

Molten

Answer 8

(adj) To be melted by heat.

Question 9

Density

Answer 9

Density is how compact something is. It is the quantity of something per unit volume, unit area, or unit length.

Question 10

Geologic Continent

Answer 10

There are 6 geologic continents: Africa, Eurasia, North America, South America, Antarctica, and Australia). They are not defined by country borders, language, culture, or race/ethnicity, but by geologic features.

Question 11

Continental Drift

Answer 11

Is the process by which continents are moving across the Earth’s surface over time.

Question 12

Fossil

Answer 12

A fossil is the remain/impression of a prehistoric creature (as of today).

Question 13

Glacier

Answer 13

A glacier is a flowing river of ice. They are found in cold regions, such as the poles, and are responsible for weathering and carving landscapes in many places.

Question 14

Ice Age

Answer 14

The Ice Age is a long period of time when global temperatures shift to the colder range, causing the poles to expand towards the equator.

Question 15

Land Mass

Answer 15

A land mass is a large body of land, such as a continent.

Question 16

Pangaea

Answer 16

Pangaea was the supercontinent (had all of today’s continents) that existed about 300 million years ago.

Question 17

Supercontinent

Answer 17

A supercontinent (such as Pangaea) was a large continent that typically was composed of several modern-day continents.

Question 18

Alfred Wegner

Answer 18

Alfred Wedner was a scientist who first proposed that all of Earth’s continents were once combined into a supercontinent named Pangea.

Question 19

Plate Tectonics

Answer 19

Is the theory that Earth’s crust is divided up into large sections, called plates, that are constantly moving and interacting with each other.

Question 20

Divergent Boundary

Answer 20

The point where two tectonic plates are moving away from each other. Earthquakes here are common, and magma rises from the Earth’s mantle to the crust, creating an oceanic crust.

Question 21

Convergent Boundary

Answer 21

The point where two tectonic plates are colliding. Depending on the density of the plates, one might submerge beneath the other, or both will force up into a mountain range.

Question 22

Transform Boundary

Answer 22

Points where two tectonic plates are sliding past each other. As they rub against each other, a huge amount of pressure can build up, causing earthquakes.

Question 23

Seafloor Spreading

Answer 23

Is when tectonic plates (oceanic) spread apart from each other because of convection in the mantle. The new material comes up to fill in the gaps left behind, creating a new oceanic crust. One example of sea-floor spreading is the mid-Atlantic ridge.

Question 24

Boundary

Answer 24

Is where two tectonic plates meet.

Question 25

Geological Feature

Answer 25

Is a feature of the Earth, such as a mountain range.

Question 26

Hot Spot

Answer 26

This is where volcanic activity is common. This is usually due to the volcano being situated on top of a fault line, or being under a large plume of magma.

Question 27

Rift

Answer 27

When a plate is being pushed away from the divergent boundary.

Question 28

Fault Lines

Answer 28

The borders of tectonic plates. Earthquakes are common around these lines.

Question 29

Hydrothermal Vent

Answer 29

A fissure in the seabed from which geothermally heated water escapes.

Question 30

Ocean Trench

Answer 30

Is a deep and narrow depression in the ocean floor. They are common at convergent boundaries.

Question 31

Earthquake

Answer 31

An earthquake is when the crust suddenly shakes violently, varying in intensity, caused by the growing tensions between two plates.

Question 32

Epicenter

Answer 32

The epicenter is the point on the Earth’s surface that is directly above the starting point of an earthquake.

Question 33

Fault

Answer 33

A fault is an extended fracture between two slabs of rock. Rocks on either side of the fault move relative to each other, really slowly, and can sometimes release their energy in the form of an earthquake.

Question 34

P-wave

Answer 34

A P-wave is a type of body wave, a seismic wave that travels through the Earth’s interior. They were the first waves to reach a seismograph (that’s how they got their name– P as in primary). They travel around 6/7 km/s.

Question 35

S-wave

Answer 35

An S-wave is another type of body wave, slower than a P-wave (S for secondary).

Question 36

Seismic Wave

Answer 36

Seismic waves are waves of motion that radiate from the focus of an earthquake. They compress and squeeze material, then release them again, traveling very rapidly.

Question 37

Seismograph

Answer 37

A seismograph is a device that responds to ground noise and shaking caused by earthquakes, volcanic eruptions, and explosions.

Question 38

Tsunami

Answer 38

A tsunami is a large wave caused by the displacement of a large body of water, or by underwater earthquakes and/or volcanic activity.

Question 39

Strike-Slip Fault

Answer 39

Strike-slip faults are vertical fractures where slabs of rock have mostly moved horizontally.

Question 40

Dip-Slip Fault

Answer 40

A dip-slip fault is an inclined fracture between two slabs of rock, where the rock mass above the fault slides down.

Question 41

Compression

Answer 41

Compression is when tectonic plates are squeezed/pushed together, making the crust shorter and thicker.

Question 42

Tension

Answer 42

Tension is the stress tectonic plates experience as they are being pulled apart, making the crust longer and thinner.

Question 43

Shearing

Answer 43

Shearing is when an area of rock has become deformed due to different stresses. These rocks can come in all sorts of formations and patterns.