Glossary

Question 1

Asthenosphere

Answer 1

A layer of mantle below the lithosphere.

Question 2

Basalt

Answer 2

Dark fine-grained igneous rock formed from the rapid cooling of low-viscosity lava, rich in magnesium and iron.

Question 3

Borehole

Answer 3

A deep narrow hole drilled down into the ground to extract, for example, oil, gas, water, or samples of rock.

Question 4

core (inner)

Answer 4

hot dense ball of mostly iron.

Question 5

Core (outer)

Answer 5

Third layer of the earth and the only liquid layer, mainly made up of the metals iron and nickel.

Question 6

Crust (continental)

Answer 6

Layer of granitic, sedimentary, and metamorphic rocks, which form the continents and the areas of shallow seabed close to their shores.

Question 7

Dolerite

Answer 7

Fine-to-medium-grained, dark grey to black intrusive igneous rock. extremely hard and tough.

Question 8

Gabbro

Answer 8

igneous rock formed in the slow cooling of magnesium rich and iron rich magma deep beneath the earths surface.

Question 9

Gutenberg Discon.

Answer 9

Marks the boundary between the mantle and core.

Question 10

Granite

Answer 10

Coarse-grained intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase.

Question 11

Lehmann discon.

Answer 11

In between the inner and outer core of the earth.

Question 12

Lithosphere

Answer 12

The upper rigid layer of the crust and upper mantle.

Question 13

Longitudinal wave

Answer 13

Waves were the displacement of the medium is in the same direction as the direction of the travelling wave.

Question 14

Low velocity zone

Answer 14

Characterised by low seismic velocities

Question 15

mantle

Answer 15

Mostly solid bulk of earths interior.

Question 16

Meteorite (iron)

Answer 16

Thought to represent the core of a planet-like object, which formed early in the history of the solar system.

Question 17

Meteorite (stony)

Answer 17

Thought to represent the mantle of a planet-like object.

Question 18

Moho

Answer 18

Boundary broadly between the crust and the mantle where P and S wave velocities decrease.

Question 19

Ophiolite

Answer 19

sections of the oceanic crust that have been tectonically moved onto continental crust.

Question 20

Partial melting

Answer 20

Occurs when a small proportion of the rock melts, usually between 1 and 5%.

Question 21

peridotite

Answer 21

An ultramafic igneous rock composed of the minerals olivine and pyroxene.

Question 22

rheid

Answer 22

A non-molten solid that deforms by viscous or plastic flow, in response to an applied force.

Question 23

seismic

Answer 23

vibration generated by an earthquake, explosion, or similar energetic source.

Question 24

seismogram

Answer 24

The paper or electronic record made by a seismograph.

Question 25

Seismograph/ seismometer

Answer 25

Device which receives and records seismic vibrations.

Question 26

shadow zone

Answer 26

an area where earthquake waves are not recorded.

Question 27

transverse wave

Answer 27

Motion in which all points on a wave oscillate along the paths at right angles to the direction of the wave’s advance.

Question 28

wave (P type)

Answer 28

One of the two main types of elastic body waves. Primary wave or pressure wave are the first signal from an earthquake.

Question 29

Wave (S type)

Answer 29

Slower velocity and are normally the second major phase to be observed on a seismogram, secondary waves.

Question 30

wave (surface)

Answer 30

Seismic wave that is trapped near the surface of the earth.

Question 31

Xenolith

Answer 31

Pieces of rock within an igneous rock which have not been derived from the original magma but have been introduced from elsewhere.