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