Earthquakes and volcanoes Definitions

Question 1

Focus/origin

Answer 1

the location of the source of an earthquake below the ground

Question 2

Epicentre

Answer 2

the location at the surface of the ground above the focus/origin of an earthquake

Question 3

Strato-volcanoes

Answer 3

high steep-sided volcanoes made from thick acid lava

Question 4

Shield volcanoes

Answer 4

low, flat volcanoes(like an upturned shield) made from runny basic lava

Question 5

Active

Answer 5

referring to volcanoes with regular eruptions

Question 6

Dormant

Answer 6

referring to volcanoes that have not erupted for many years but still have some detectable activity

Question 7

Extinct

Answer 7

referring to volcanoes which will not erupt again as no activity can be detected

Question 8

Magma

Answer 8

molten rock found beneath the earth’s crust

Question 9

Lava

Answer 9

magma that has escaped from beneath the Earth’s crust and has flowed onto the surface

Question 10

Tectonic plates

Answer 10

rigid segments of rock that make up the Earth’s crust(they meet at plate boundaries where earthquakes, volcanoes and fold mountains are created)

Question 11

Plate boundaries

Answer 11

the edge of a tectonic plate where earthquakes, volcanoes and fold mountains are formed or take place

Question 12

Convection currents

Answer 12

heat-driven currents of fluid that are created due to differences in the temperature of material beneath the plates of the Earth’s crust

Question 13

Hot spots

Answer 13

parts of the Earth’s crust which are thin enough to let magma through to form a volcano

Question 14

Glacial

Answer 14

to do with ice, its movements and the features formed by it

Question 15

Lahars

Answer 15

volcanic mudflows that contain a mixture of rocky debris, ash and water(it usually flows down a river valley from a volcano)

Question 16

Mudflows

Answer 16

mass-movements of rocks and soil down a slope that is often triggered by heavy rain(volcanic ash often develops into mudflows)

Question 17

Richter scale

Answer 17

a numerical scale used to rate the magnitude of an earthquake(each whole number is ten times the magnitude of the previous one; an earthquake of magnitude 7 is ten times more powerful than one of magnitude 6)

Question 18

Crater

Answer 18

an (approximately) circular depression in the ground caused by volcanic activity and that usually lies above the vent from which volcanic material is ejected

Question 19

Magma chamber

Answer 19

the location beneath the vent of a volcano where magma is stored prior to eruption

Question 20

Vent

Answer 20

an opening on the Earth’s surface where lava flows from, fragmented rocks are erupted, and volcanic gases are emitted

Question 21

Subduction

Answer 21

the process in which one of the Earth’s plates slides under another

Question 22

Trenches

Answer 22

long, narrow depressions on the seafloor that form at a plate boundary due to subduction

Question 23

Ridge

Answer 23

an elevated, long and narrow strip of land