earthquakes 1

Question 1

what is an earthquake?

Answer 1

a sudden and violent shaking of the ground as a result of movements within the earth’s crust or volcanic activity

Question 2

what is quake?

Answer 2

to shake or tremble

Question 3

what is seismic?

Answer 3

relating to earthquakes or other vibrations of the earth and its crust

Question 4

what is seismology?

Answer 4

the study of earthquakes

Question 5

what is a seismologist?

Answer 5

scientist who studies earthquakes

Question 6

how many earthquakes are detectable each year?

Answer 6

over 500 000

Question 7

how many earthquakes each year are felt by humans?

Answer 7

100 000

Question 8

how many earthquakes each year cause damage and/or death?

Answer 8

100

Question 9

what happened since the start of october 2023?

Answer 9

multiple earthquakes have hit western afghanistan. approximately 1500 people have died and 2000 have been injured

Question 10

what is a tectonic plates?

Answer 10

earth’s entire crust and upper mantle (lithosphere) can be divided into large rocky plates, 7 major tectonic plates and 8 minor tectonic plates

Question 11

what are the major tectonic plates?

Answer 11

north america plate, eurasian plate, pacific plate, south american plate, african plate, australian plate and antarctic plate

Question 12

what are the minor tectonic plates?

Answer 12

juan de fuca plate, caribbean plate, cocos plate, nazca plate, scotia plate, arabian plate, indian plate and philippine sea plate

Question 13

what is the asthenosphere?

Answer 13

partially molten layer of mantle

Question 14

what does asthenosphere move due to?

Answer 14

moves due to heat transfer and rise and fall of partially molten rocks within it
when asthenosphere below moves, tectonic plates are dragged along and move too

Question 15

what is friction?

Answer 15

Due to ASTHENOSPHERE movement, TECTONIC PLATE edges may slide against each other.
FRICTION where plates meet may slow and/or prevent their motion, resulting in a build up of pressure.
FRICTION:
✓ Resistance a surface or object encounters when moving over another.
✓ A force that opposes motion (sliding, rolling) of one object over another.

Question 16

what does the release of built-up pressure release and what happens when this occurs?

Answer 16

seismic waves
When this occurs, sections of Earth’s crust can literally break apart and be displaced, resulting in an EARTHQUAKE.
Such EARTHQUAKES are known as TECTONIC EARTHQUAKES.

Question 17

where do a majority of large tectonic earthquakes occur?

Answer 17

along the “circum-Pacific seismic
belt”/ along the rim of the Pacific Ocean

Question 18

the “Circum-Pacific seismic belt” is also home to some of the world’s most powerful volcanoes and is known as

Answer 18

ring of fire

Question 19

give some example of important earthquake zones.

Answer 19

➢ Alpide belt (home to the recent Afghanistan. earthquakes).
➢ Mid-Atlantic ridge (where DIVERGENT PLATE boundaries are encountered).

Question 20

what is a hypocenter?

Answer 20

point in Earth’s interior where EARTHQUAKE originates

Question 21

what is an epicenter?

Answer 21

➢ point ON Earth’s surface directly above the HYPOCENTER
➢ point ON Earth’s surface where SEISMIC WAVES are first felt/where waves first arrive.

Question 22

what are seismic waves?

Answer 22

vibrations that travel through (body of)
Earth or along its surface when an EARTHQUAKE occurs

Question 23

what is a body wave?

Answer 23

move/travel through Earth

Question 24

what is a surface wave?

Answer 24

move/travel along Earth’s surface

Question 25

what are the 2 types of body waves?

Answer 25

p-WAVES (short for PRIMARY WAVES): Named this way as they are first waves detected by SEISMIC recording stations (that monitor earthquake activity) following an earthquake. s-WAVES (short for SECONDARY WAVES): Arrive at SEISMIC recording stations after the p-WAVES.

Question 26

what are the characteristics of p waves?

Answer 26

✓ cause surface of Earth to EXPAND and CONTRACT in direction of wave travel (PARALLEL to wave travel). ✓ can travel through SOLIDS, LIQUIDS and GASES. ✓ can travel through CRUST, MANTLE, OUTER CORE (which is liquid) and INNER CORE (which is solid).

Question 27

what are the characteristics of s waves?

Answer 27

✓ cause surface of Earth to RISE and FALL. ✓ surface moves PERPENDICULAR to direction of wave travel. ✓ can travel through SOLIDS. ✓ can travel through CRUST and MANTLE. ✓ cannot travel through OUTER CORE (which is liquid) and therefore never reach INNER CORE (which is solid).

Question 28

what are some characteristics of surface waves?

Answer 28

follow the faster BODY WAVES (i.e., p- WAVES and s-WAVES). ✓ much SLOWER than BODY WAVES. ✓ SURFACE WAVES ONLY travel along Earth’s SURFACE. ✓ SURFACE WAVES ONLY travel through SOLIDS. ✓ SURFACE WAVES more destructive than BODY WAVES.

Question 29

what are the 2 types of surface waves?

Answer 29

✓ LOVE WAVES (the faster of the two) ✓ RAYLEIGH WAVES

Question 30

what are the characteristics of love waves?

Answer 30

✓ travel HORIZONTALLY ✓ cause Earth’s surface to move from SIDE to SIDE PERPENDICULAR to direction of WAVE motion.

Question 31

what are the characteristics of Rayleigh waves?

Answer 31

✓ travel HORIZONTALLY ✓ cause Earth’s surface to shake in an Elliptical pattern (i.e., ROLLING PATTERN). ✓ cause Earth’s surface to move like ocean waves. ✓ spread out most (of all waves) and last for longest period of time.