GEOL quiz 5

describe how sulfate aerosols are made

a volcano erupts -> sulfur from the magma chamber is released into the atmosphere -> interacts w/ other molecules Z& creates tiny aerosol particles = sulfate

the layers of lava & pyroclastic are ____

alternating

pyroclastic hazards (3)

ash lapilli blocks & bombs

lahars are a mixture of __ & ___

ash & water

bombs are molten material that cooled off in the _____

atmosphere

troposphere

atmosphere where clouds form easiest

stratosphere

atmosphere where its hard to make clouds

lahar has a consistency of _____ and leaves a thick layer of _____ behind that can bury cities

concrete mud

what is rare about cone shaped volcanoes?

cone shaped volcanoes are rare in that they erupt pyroclastics with mafic/intermediate magma. Normally magma must be felsic in order to be explosive enough to create pyroclastics

ash is the most ____ of the pyroclastic hazards

dangerous

composite/stratovolcanoes are some of the most _____ volcanoes

dangerous

large fissures occur at ____ _____ boundaries, and ____ ___

divergent plate hot spots

_____ can cause the gases at the bottom of lakes to explode

earthquakes

volcanic hazards (6):

earthquakes lava (mafic & felsic) pyroclastic flows lahars volcanic gases tsuanimi

tsunamis can be caused by (2)

earthquakes oceanic volcano violently erupting

lahars can be created even with no ___

eruption

flank fissures are

eruptions from cracks on the sides of volcanoes

a pyroclastic flow is a _____-______ mixture of hot volcanic ______ & _____

fast-moving gas & ash

calderas are ____ to ______ chemistry

felsic to intermediate

cone volcanoes may form on the _____ of larger volcanoes

flanks

fissure eruptions occur when volcanic material erupts from extensive _____ above a ___ ___

fractures magma chamber

Ways to monitor volcanoes (4)

gas sampling ground deformation thermal imaging seismic monitoring

volcanoes contain ____ that can slowly leak out of the chamber

gases

ash is essentially microscopic sized pieces of ____

glass

pyroclastic flows move on the _____ surface

ground

lava domes form from ____ _____ lava flows, meaning ____ magma

high viscosity felsic

tsunami runup

how high above sea level the wave reached

flood basalt

huge amounts of lava that erupt from fissures happens in the case of mafic magma

composite/stratovolcanoes are common above ____ composition magmas

intermediate

composite/stratovolcanoes have an _____ chemistry

intermediate

pyroclastic flows are mostly from ____ & ____ magma chambers

intermediate & felsic

______ are good candidates for volcanic tsunamis

islands

any volcano that can erupt has the potential to create ___

lahars

gases can buildup & become trapped in the mud at the bottom of ____

lakes

calderas are likely formed from previous _____ ______

large eruptions

composite/stratovolcanoes form from overlapping ____ flows & ____ material

lava pyroclastic

volcanoes formed dominantly from lava (2)

shield volcanoes lava domes

Shield volcanoes- size & shape

shield volcanoes are the largest volcanoes they're generally flat with a little slope

shield volcanoes release dominantly _____, with less _____ material

lava pyroclastics

lava dome size:

lava domes are small

main hazard of shield volcanoes

lava flows

volcanic-hazard map

show how at risk you are depending on the area you're in

cone volcano's: shape, size, & lifespand

steep-sided, small, and short-lived

a significant collapse results the slow ________ (sinking) of the entire surface

subsidence

volcanoes that are ____ rich can actually cool the planet

sulfur

_____ + _____ = sulfate aerosols

sulfur + oxygen

a minor collapse is a ___ ____

summit caldera

____ + _____ cools the planet

sunlight + sulfur

shield volcanoes age

super old; live a long time

gas sampling

taking gas measurements near active volcanoes

lava flows are _____ deadly than pyroclastic hazards

less

shield volcanoes form from ____ ____ lava flows, meaning ____ magma

low viscosity mafic

fissure eruptions are generally ____ magmas

mafic

cone shaped volcanoes commonly form from explosive eruptions above ___ to _____ magma chambers

mafic to intermediate

during a significant collapse, a violent eruption partially empties the ____ ____

magma chamber

ground deformation

measures tilt in earths surface

composite/stratovolcano size

medium sized

greenhouse gases such as _____, ____ ____, & _____ _____ slow the escape of ________ radiation & warm the planet

methane, carbon dioxide, & water vapor terrestrial

seismic monitoring

monitoring for earthquakes

Ash is also called

tephra

volcanoes are

mountains formed from eruptions of molten rock

thermal imaging

the color indicates the wavelengths

pyroclastic flows are some of the most dangerous because

they are hard to predict

mafic lava flows are more dangerous than felsic lava flows because

they're more common and faster

volcanoes formed dominantly from pyroclastics (3)

tuff cones scoria cones cinder cones

ways to mitigate volcanic hazards (3)

volcanic explosivity index monitoring hazard maps

volcanic landforms with no mountain (2)

volcanic fissures calderas

lahars are

volcanic mud flows

the size & shape of any volcano depends on the ___ & ____ of the magma erupted

volume & viscosity

volcanic gases that are also greenhouse gases (3)

water vapor, methane, & carbon dioxide

describe how volcanic gases affect the greenhouse effect

water vapor, methane, & carbon dioxide are released from volcanoes -> absorb terrestrial radiation when it tries to leave -> warms the planet

a tsunami is an ocean going wave which is not driven by the _____ or the ______

wind tides

mt. st. helen eruption vs. yellowstone eruptions -differences in eruptions -> why?

-Mt St Helen is an island arc, meaning it is created through oceanic crust. Oceanic crust leads to only mafic magma and mafic magma is less viscous and therefore less explosive than yellowstone. Yellowstone was created from a continental hotspot. This means that it has mostly intermediate and felsic magma. Felsic and intermediate magmas are more viscous and more explosive, so their eruptions will be more violent.

hazards of ash falls

-can bury cities/cause buildings to collapse -respiratory hazard (scar lung tissue) -eye irritant -grazing animals can ingest from eating grass -air travel -> can break down plan engines -electrical outages -radio & phone disruption (ash blocks radio waves) -lahars -pyroclastic flows -lightning (ash generates charge separation in ash clouds which can cause lightning)

most volcanic hazards are associated with _____ viscosity magma bodies, or ___ magma

-low -mafic

ash is normally about __mm

2

lapilli is ___mm

64

blocks and bombs _____mm

>64

______ is a deadly gas that is released when this happens

Carbon dioxide

example of shield volcano

Mauna Loa, Hawaii

examples of composite/stratovolcanoes

Mt Ranier Mt St Helens

example of lava dome

Mt. St. Helens, Washington lava dome forming in the crater of a stratovolcano

lava domes eruption will be

big

blocks shape

blocks are more rugged shaped

bombs shape

bombs are usually tear shaped

calderas are circular to elliptical depressions where the surface has partially _____ into the ___ ____

collapsed magma chamber

3 ways that pyroclastic flows can be made

collapsing ash column lateral blast (eruption from the side) lava dome collapse

volcanoes formed from mixtures of lava & pyroclastics are called ___/_____

composite/stratovolcanoes

ash falls are usually due to _____ volcanoes or large _____ eruptions

composite/stratovolcanoes caldera

shield volcanoes are common in ______ hot spots how do we know this?

oceanic -we know this because shield volcanoes produce mafic magma. mafic magma is associated with oceanic crust because oceanic crust is denser & thinner, so magma cannot reach felsic or intermediate levels.

shield volcanoes create ____ crust, which is ____ rock

oceanic basalt

cone shaped volcanoes involve ___ crust because

oceanic mafic magma

volcanoes cannot throw bombs/blocks very far because

of their size

describe how sulphate particles affect climate

once they get high in the atmosphere its hard for them to come down -> they either reflect or absorb energy but either way that energy is not reaching earths surface -> lowering insolation values -> cooling the earth

volcanic aerosols

particles in the air or small ash in the atmosphere

lava domes can ___ larger volcanoes

plug

Volcanic Explosivity Index (VEI)

ranges from 0-8 classified by how much material is erupted in a single event

pyroclastic flows are a mixture of

rock & ash