Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

earth sci sem 2 > volcanoes and volcanic activity > Flashcards

volcanoes and volcanic activity Flashcards

1
Q

volcanic erruptions

A
  • an event during which lava and/or pyroclastic debris expelled from a volcanic vent
    -there is verylittle we can do to control volcanic eruptions. we dont fully understand the process and we need to know the process to be able to mitagate
  • iceland has good ways to deal with erruptions because they have increased volcanic activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

magma

A

molten rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

lava

A

magma th at reaches the earth’s surface (will eventually cool)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

krakatoa

A
  • sound heard 3000 miles away
  • 40m high tsunami killed over 36000 people
  • high ash coud produced
  • one of the biggest agents to impact global temperature
  • global temp reduced 0.5C for 10 years after krakatoa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the affect of ash clouds

A
  • decreases albedo
  • light reflects off ash clouds thereby decreasing global temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Anak Krakatau (indonesia)

A
  • active from july 2018- may 2019
  • lies in crater of krakatoa
  • major collapse in 2018 causes a tsunami which killed over 400, injured over 7000, and displaced over 40000
  • volcano lost more than two thirds of its height and volume in one week
  • pheratic, explosive erruption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

steam explosions

A
  • island arcs: seawater seeps into rock and comes into contact with magma
  • steam produced and blows volcano (pheratic eruption which are very disrupive; ground/seamwater connected to and acting with volcanic chambers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Jokulhlaups in Iceland

A
  • a type of glacial lake outburst flood (subglacial)
  • often associated with subglacial outburst floods caused by volcanic eruptions
  • eruption melts water and builds up pressure
  • can deposit/ erode sedimens and change proglacial landscape dramatically
  • ex Eyjafjallajokull eruption in iceland created over 140 events; glacial activity and volcanic together; 10 million cubic meteres of water, tephra and sediment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

underwater volcano in tonga on jan15

A
  • 5 people killed
  • largest eruption since 1991 mount pinatubo
  • ash cloud
  • shockwaves felt across the globe
  • magma was forced upward at high highspeed
  • high speed contect with cold sea water causes “fuel-cooland interaction” building up lots of pressure
  • magma torn apart exposing fragments to more sea water
  • chain reaction and massive chemical explosion
  • particles forced up to hypersonic speed
  • people on tonga faced drinking water crisis
  • caused a massive oil spill in peru
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why s it important to understand how volcanoes work?

A
  • many people are killed or displaced
  • we cant prevent volcanoes but we can be prepared for them to preent loss of life and individuals wellbeing
  • to understand the nature of earth’s interior
  • magma comes from the matles
  • there is kimberlite and diamonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is geothermal energy

A
  • using heat from the earth for electricity
  • commonin New Zealand, Iceland, BC, and Chile
  • often near volcanoes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

pyroclastic debris

A
  • lava and rock fragments ejected in a volcanic eruption
  • theres different scales: lapilli (small amount of lava and rock fragments) and lava bomb (large amounts of lava, larger than 2.5 inches)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

volcano

A
  • hill or mountain produced by volcanism
  • volcano doesnt have to be active to be considered
  • the name is based on how it was formed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

vent

A

opening through which eruption takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

crater

A

depression over the vent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

caldera

A

depression >1km
- same as crater but just larger

17
Q

where do we find volcanoes

A
  • divergent plate boudnaries ex. mid ocean ridges, Iceland
  • convergent plat boundaries ex. pacific ring of fire, krakatoa, cascade volcanoes (mt. st. helens)
  • hot spots: not associtaed with plate boundaries. ex. hawaii, yellowstone. related to mantle plumes. plume is stationary, plate moves. chain of volcanic islands produced
18
Q

plumes

A

narrow colums of hot rock

19
Q

how many types of lava are there

A
  • 2 types
  • affects style of erutpion and type of volcano produced
  • silica content of magma is critical
    types:
  • silica rich (felsic) lavas
  • silica-poor(mafic) lava
  • intermediate lavas
20
Q

silica-rich (felsic) lava

A
  • very viscous, flow slowly
  • gases cannot escape easily
  • violent erruptions, explosive
  • ex. rhyolite
  • iceland
21
Q

silica-poor (mafic) lava

A

-low viscosity, flow easily
- gases escape easily
- quite eruptions, lava flows
- ex. basalt
- hawaii and iceland

22
Q

intermediate lavas

A
  • ex. andesite
23
Q

types of volcanoes

A
  • 3 main types
  • shield
  • cinder (pyroclastic) cone
  • composite (stratovolcano)
24
Q

hot spots

A
  • a region deep within the Earth’s mantle from which heat risen is not associted with plate boundaries
25
Q

shield volcanoes

A
  • broad, sloping cones (slopes between 2 and 10 degress)
  • low viscosity lava flows (silica poor (mafic))
  • non-violent eruptions
  • ie. hawiian islands (mauna loa)
  • basaltic lavas flow easily
  • two types: pahoehoe and A’a
  • spatter cones (shield volcanoes with smaller vents): formed on shile volcanoes when gas is trapped in cooling lava, usually less than 10 m in height
  • composition: basalt, laers of solidified lava flows
  • very large
26
Q

pahoehoe

A
  • ropey
  • hot lava
  • in silica poor lavas
  • liquidy
27
Q

A’a

A
  • sharp, jagged (cooler)
28
Q

(cinder) pyroclastic cones

A
  • made of loose pyroclastic debris
  • steep slopes, small
  • felsic or intermediate lavas
  • formed when gas escapes
  • 50-350m in height
  • violent eruptions
  • ex. sunset crater, arizona
  • steep slopes, 33 degrees
  • smallest of the three types
  • composition: pyroclastic fragments of any compositions. basalt is most common
29
Q

Composite volcanoes (stravolcanoes)

A
  • alternating lava flows and pydroclastic debris
  • intermediate steepness
  • form over long period
  • can be very large
  • mostly associted with intermediate lavas (andesite) and violent eruptions
  • ex. mt. st. helens (usa), mt etna(italy), mt vesuvius (italy)
  • associted wih lots of hazards
  • slopes less than 33 degrees
  • considerably larger than cinder cones
  • composition: layers of pyroclastic fragments and lava flows. mostly andesite
30
Q

what kinds of hazards are produced by volcanoes

A

lava flows (nothing we can do to stop lava)
- destructive to proterty, roads, etc
- ex of volcanic hazars. 2018 kilauea eruption, hawaii

pydroclastic debris (volcannic bombs, ash which can contaminate water supply)
- ex. mt st helens which was the most destructive explosion in continental usa in recent human history

pyroclastic flows (nuees ardente; mixture of hot gases and volcanic debris, travels at >100km/hr, extermely dangerous, mixture of toxic and hot gases coming at you, lots of human deaths due to this, cant stop it, NOT seen in shield volcanoes)
- ex. mont unzen (japan) in 1991
- ex. st.piere, martinique,1902, mt pelee, killed 28000, only 2 survivors

debris flows (lahars): mudflows (pyroclastic material debris and water), flow along river valleys; less destructive than pyroclastic flows
- ex. nevado del ruiz, colombia: lahars reachers speeds of 50km/hr, over 23000 dead

toxic gases: water vapour, co2, co, hydrogen sulphide, sulpher dioxide, heavier than air, move along topographic depressions
- ex. lake nyos, cameroon, 1700 people killed by c02

31
Q

natural hazard

A

what nature does

32
Q

natural disaster

A
  • humancentric
  • is a disater if it impacts society/people/infrastructure
33
Q

types of volcanic explosions

A
34
Q

How are different types of volcanoes, volcanic activity and volcanic rocks related to plate tectonic setting?

A

earth sci sem 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions