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Science | 7th Grade > Unit 7: Geology - Earthquakes, Volcanoes, and Rocks > Flashcards

Unit 7: Geology - Earthquakes, Volcanoes, and Rocks Flashcards

1
Q

Can we predict earthquakes?

A

Cannot be predicted but:
- Location: more likely occur plate boundaries
- Magnitude: no
- Frequency: yes, general patten over long periods time
- When: no, except some after shocks

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2
Q

How do earthquakes occur?

A
  • Convection –> Earth’s surface move –> creates stress on rocks
  • Stress buildup –> rock will break/chip –> plates lurch forward –> earthquakes
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3
Q

Magnitude

A

Describes amout energy released by earthquake

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4
Q

Richter Magnitude Scale

A
  • Numerical rating system measure energy/magnitude of largest seismeic wave of earthquake
  • Based on height/amplitude of seismograph
    Pro:
  • Quick –> taken after earthquake
    Con:
  • Not as accurate
    Ex. 5 –> 7 (two steps) –> 10 x 10 = 100 times more shaking (exponents)
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5
Q

Moment Magnitude Scale

A
  • Measures energy released taking into size of fault breakes, motion occurs along fault, strength rocks break
    Pro:
  • More accurate by taking info + using tools
    Con:
  • Takes longer
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6
Q

Modified Mercalli Intensity Scale

A
  • Descriptions about earthquake damage (people)
  • From I (not noticeable –> XII (everything destroyed)
  • Locates epicenter
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7
Q

What does the amount of damage and earthquake produces depend on?

A

Surface materials, design of structures, distance from epicenter

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8
Q

Earthquake Hazards

A

Earthquake damage factors

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9
Q

Pancaking

A

Supporting walls fall –> debris looks pancaked

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10
Q

Building Height

A
  • Buildings = natural vibration
  • Build vibration = seimic waves –> build fall over
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11
Q

Local Geology

A

Loose sediment –> move movement
Ex. Liquefaction + Landslide

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12
Q

Liquefaction

A

Buildings sink + collapse in soil (ground act liquid) –> loose sediment

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13
Q

Landslide

A
  • Downhill movement of soild, loose rocks, boulders
  • Ground material - soft materials = amplified –> unconsolidated sediments
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14
Q

Can we predict when a volcano will erupt?

A

Yes, but exact moment cannot:
- Location: yes - specific locations –> usually at plate boundaries but sometimes hot spots
- Magnitude: no
- Frequency: Yes, sort of - over HUGE periods of time
- Exact Timeing: No, but there some warnings eruption coming
Warnings:
- Gas emissions
- Deformation of mountain
- Ground vibrations (earthquakes)
- Heat changes
- Lava patterns/changes

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15
Q

Hot Spots

A

Volcanoes not found at plate boundaries
- Lava goes through cracks –> hardens reach surface –> plates move

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16
Q

Mudflows

A

Volcano thermal energy = melt snow + ice –> mix mud + ash –> mudflows = lahars

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17
Q

Lava Flows

A
  • Melts everything
  • Hardens –> thick, black layer rock –> farmland lost + homes cannot rebuild
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18
Q

Volcanic Ash

A
  • Disrupts air traffic
  • Engines stop
  • Damage electricity, farm machinary, crops
  • Affect air quality + cause breathing problems
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19
Q

Volcanic Gases

A

Magma include sulfer dioxide = irritate skin/eyes = carbon dioxide deadly

20
Q

Landslides

A
  • Downhill movement of soil, rocks, boulders
  • Mountain shakes –> rocks weakened
21
Q

Pyroclastic Flows

A

Fast-moving avalanch of hot gas + ash
>100 km/hr
>1,000 degrees Celsius

22
Q

What can volanoes affect when it erupts?

A
  • Affect all Earth’s systems
  • Have 1 or more hazards
23
Q

What do scientists monitor from a volcano?

A
  • Gas
  • Deformation
  • Ground vibration
  • Remote sensing
  • Lava collection
24
Q

Gas

A

Increase in certain gases –> potential eruption

25
Q

Deformation

A

Use equipment to see if ground tilted, sunken, or bulge from pressure (lava/magma rising)

26
Q

Ground Vibration

A

Earthquakes beneath volcanoes (seismic activity)

27
Q

Remote Sensing

A

Use remote sensing determine how much heat given off (more heat –> lava close to surface

28
Q

Lava Collection

A

Scientists get lava sample for temperature to determine properties of lava before eruption

29
Q

Weathering

A
  • BREAKS DOWN rock, soil, minerals, wood, articial materials
  • Happens by: water, gases, organisms
30
Q

Erosion

A
  • MOVES soil, rock, dissolved material from one location and transports another
31
Q

Deposition

A
  • DROPS sediment to new location –> buildup of sediment
  • Happens by: wind + water
32
Q

Rocks

A
  • Solid mixtures of minerals, smaller rock fragments, organic matter, glass
33
Q

Minerals

A
  • Inorgranic
  • Definite chemical composition + arrangement of atoms
34
Q

The Rock Cycle

A

Series of “processes” change one type rock into another type. Energy comes from sun and core of Earth.

35
Q

Three magor groups of rocks

A

Igneous, sedimentary, metamorphic

36
Q

Magma

A

Molten rock inside Earth

37
Q

Lava

A

Molten rock on Earth’s surface

38
Q

Crystalization

A

Magma/lava cools –> particles solidify because cools –> crystals

39
Q

Igneous Rocks

A

Form when hot, molten rock “crystalizes” and “solidifies.” Sometimes called primary rock b/c young.
Extrusive:
- Forms on surface
- Cools quickly b/c temp. suddenly pluments on surface –> little crystals
Intrusive:
- Insde –> takes lover cool –> more time crystals grow

40
Q

Sediment

A

Rock material forms when rocks broken down into smaller pieces of dissolved in water

41
Q

Lithification

A
  • Sediment turns into rock
42
Q

Compaction

A
  • Weight from layers of sediment force fluids out –> space decreases
43
Q

Cementation

A

Water crystallizes between grains of sediment –> minteral cement holds grains together

44
Q

Sedimentary Rock

A

Form from compaction + cementation of “sediment” and even from dead organisms.
Clastic:
- Broken pieces of minterals + rocks –> clastic
Chemical:
- Minterals crystallizes from water –> water evaporates + form minterals
Biochemical:
- Rocks contain organisms b/c compacted + cemented together

45
Q

Metamorphic Rocks

A

Rocks form from other rocks through heat + pressure
- Go to surface by uplift when oceanic plate subducts under plate –> pushing plate upwards forming (convection) mountains + rocks (slow)
Foliated:
- Bands/layers/rows of rock because pressure
Nonfoliated:
- No bands/layers/rows because depends on type of rock

46
Q
A

Science | 7th Grade (9 decks)

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