earth science test 8

Question 1

what is an earthquake

Answer 1

the breaking of and movement of rocks within the lithosphere.

Question 2

what are faults

Answer 2

faults are fractures in earht where movement has occurred.

Question 3

what is focus

Answer 3

the point in earth where the energy is released and most damage occurs

Question 4

how much ditance is most foci at from earths surface

Answer 4

65km some can be 700km

Question 5

what is epicenter

Answer 5

the point on earths surface directly above the earthquake focus

Question 6

when did elastic rebound start

Answer 6

after the 1906 san fransisco earthquake

Question 7

how do earthquakes form

Answer 7

when rock that have been subject to great forces reach their limit and burst . Releasing the remaining energy as seismic waves.

Question 8

what are the three types of rorces that act on rock

Answer 8

Tension, sheering, and compression

Question 9

tension

Answer 9

force that pulls rocks apart. middle becomes thinner like gum

Question 10

compression

Answer 10

force that squeezes rocks together until it folds or breaks

Question 11

sheering

Answer 11

force that causes rocks on either side of fault to slide past each other this can cause rock to break slip apart or change shape

Question 12

what is elastic deformation

Answer 12

if you take an elastic and stretch it, it will bend and stretch according to the force applied

Question 13

what are examples where elastic energy is stored

Answer 13

when you stretch rubber band or compress a spring

Question 14

what is elastic rebound

Answer 14

when the force is released it returns to original shape like a stick. But if in too much stress it will stayed destroyed.

Question 15

what are the two types of seismic waves

Answer 15

body waves, and surface waves

Question 16

what are body waves

Answer 16

they carry energy away from the focus through earths interior to surface consists of P and S waves

Question 17

Surface waves

Answer 17

they travel at the surface

Question 18

describe P wave
How does crust move

Answer 18

they move through earth causing particles in rocks to move back and forth in the same direction the wave is moving.

Question 19

what can P waves move through? what do they cause ground bulding to so

Answer 19

solids liquids and gases. Buckle and fracture

Question 20

what are S waves
HOw does crust move

Answer 20

they move through earth by causing particles in rocks to move at right angles to the direction of the wave. Crust moves side to side and up and down.

Question 21

at what speed do primary waves move compared to S waves

Answer 21

twice as fast.

Question 22

what can S waves travel through

Answer 22

Only Solids.

Question 23

What are surface waves

Answer 23

waves that travel outward from the epicenter on the surfaceo of the earth> they move by going in a elliptical motion

Question 24

What causes things in an earthquake to fall

Answer 24

waves

Question 25

what is the slowest type of wave

Answer 25

surface waves

Question 26

what records seismic waves

Answer 26

seismograph

Question 27

How does a seismograph work

Answer 27

A pen hangs from the weight, and a rotating drum with paper sits below it on the base. When the earth shakes from an earthquake, the drum rotates, and the weighted pen moves back and forth due to the motion of seismic waves. The pen records the movement on the drum.

Question 28

What does amplitude say about the size of an earthquake

Answer 28

The larger the amplitude (height of lines) the larger the size of the earthquake.

Question 29

what waves produces the largest disturbance of a seismograph

Answer 29

surface waves

Question 30

what is seismic shaking

Answer 30

the ground vibrations produces by seismic waves

Question 31

what happens to brick and wood building during seismic shaking

Answer 31

Brick buildings may collapse, and wood framed buildings may remain intact but could be jolted off their foundations can also damage or destroy bridges.

Question 32

what does the Richter moment magnitude and Merali scale do?

Answer 32

The Richter and moment magnitude measure earthquake magnitude. And the Mercalli scale is based on earthquake intensity

Question 33

how can earthquake damage and loss of life be reduced?

Answer 33

determining earthquake risk to area, building earthquake resisitant structures, and following eartquake safety procedures

Question 34

what are the layers the earth can be divided into based on physical properties

Answer 34

lithosphere, asthenosphere, upper mantle, lower mantle, outer core, Inner core.

Question 35

earths layerd structure key 3

Answer 35

during the twentieth century studies of the paths of P and S waves through earth help scientists to establish the boundaries of earths layers and determine that the outer core is liquid.

Question 36

what is liquefication

Answer 36

happens when wet doil that is solid most of the time acts more like a liquid when it is shaken during an earthquake.

Question 37

If you live on the coast what sometime follows earthquakes

Answer 37

tsunamis

Question 38

where do most earthquakes occur

Answer 38

at plate boundaries/pacific ocean

Question 39

How do you assess earthquaek risk

Answer 39

By plotting the distribution of earthquakes on a map to determine a pattern.

Question 40

what are some seismic safe designs

Answer 40

Bridges with rubber band holding them. Gas lines with flexible pipes and auto stop. Wood framed houses built on solid ground reinforced and bolted to the ground.

Question 41

what two main type of evidence geologists use to learn about earth’s interior.

Answer 41

Direct evidence from rock cycles, and Indirect evidence of seismic waves

Question 42

What are the three major layers of earth

Answer 42

mantle, core, and crust.

Question 43

what is the density of crust compared to age

Answer 43

180 million=3.0g/cm
4billion=2.7gcm

Question 44

what is crust

Answer 44

the top layer of the earth’s surface and the thinnest one.consists of granite rock lkebasalt and gabbro.

Question 45

what is mantle

Answer 45

The layer under the crust. It begins near 40km beneath the surface. A solid layer of very hot rock, that is nearly 3000km thick.

Question 46

what is core

Answer 46

The core is the inner most layer. about 3480km thick. The center is very hot and contains lots of iron rich materials. The core has extreme pressyre and a density of 13g/cm

Question 47

what is the lithosphere

Answer 47

A combination of the uppermost mantle layer and crust. cool layer

Question 48

What is the asthenosphere

Answer 48

The layer below the asthenosphere this material is hotter and under increasing pressure this layer is less rigid than the layer above it making it somewhat soft.

Question 49

what is the lower mantle

Answer 49

a layer beneath the asthenosphere, it is a solid layer thatextends all the way to earths core.

Question 50

outer core

Answer 50

The liquid outer core is above the solid inner core. the flow of metallic iron generates earths magnetic fields.I

Question 51

Inner core

Answer 51

The cores center has a radius of 122okm. even though is is very hot it is a solid due to pressure and very dense. SO much so that molecules cant spread and become liquids.