chapter 13smsdhs.ss13.sharpschool.com/userfiles/servers/server... · 2017. 7. 18. · divergent...
TRANSCRIPT
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Chapter 13
+1000 F 2000 F
2000 F
1000 F
Ocean Crust = Basalt
Continental Crust = Granite
Temperature / Composition
Magma for volcanoesdoes not come from Earth'score
outside the earth
Thin / RunnyHot Maple Syrup
Thick / PastyCold Maple Syrup
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Hawaiian Volcanoes
Mt St Helens
High SilicaHigh WaterExplosive
Ash & CinderSmall rock
Mt Capulinpg 202203
Eldfell, Iceland
1000s m
Low SilicaLow WaterQuiet Eruptions
pg 202 Mauna LoaPahoehoe Hot Runny Silky Rope likeAa Cooler Sharp Jagged Rocks
1000 km
Car RadiatorPressure CapTemp exceed 230240F
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Aa
PahoehoeHotterRopey Silky
CoolerSharp Jagged
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Continental / Ocean Plate BoundaryOcean crust and Continental crust melting
Quiet eruptionThin Runny Lava
Thick / Pasty LavaExplosive Eruption
Mt St Helens pg 203
Strato
Cascade Mountains Pacific NorthwestCalifornia, Oregon, Washington
High SilicaLow Water
Interbedded lava flows
Rebuildingthe mountain
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Silica = thickness of magma
A lot of Silica = Thick pastyLittle bit of Silica = Thin runny
Water ContentA lot of water = High pressureLittle or no water = Low pressure
= Pressure control
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1 km 3 ejected from Mt St Helens
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Thin Runny LavaQuiet EruptionHot = 2000 F
Thin LavaFountain over 1000 ft highNot Explosive
Thick MagmaForms a Plug = Dome
Rebuilding1000 F
How Water Content and Silica Affect Eruptions
Shield Volcanoes
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Cold, Old Hard Rock Formations
Although there are some variations in the types of volcanoes and their eruptions, the features associated with volcanoes are mostlythe same across all types. Below are the definitions of intrusiveigneous rock features that are illustrated in the diagram on thetop of the previous page.
Sill magma that has cooled and hardened parallel to existingrock layers.Dike magma that has cooled and hardened perpendicular to existing rock layers.Laccolith similar to sill but formation has pushed above rock layers into a lens / dome shapeBatholith large mass of rock that was the central magma chamberVolcanic Neck central pipe through which magma traveled to surfaceStock / Boss similar to Batholith only smallerCaldera old volcanic crater (can fill with water to form a lake)
From diagramon previous page
The material thrown from a volcano is classified generally as pyroclastic material or tephra. The particles are classified below
< 2 millimetersUp to 64 millimeters> 64 millimeters
Blocks and bombs are similar except that blocks solid as they are thrown from the volcano, while bombs are liquids that cool and harden as they fall.
Football shaped
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50 km3 of material
ejected
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Divergent Boundaries
Convergent / Collision
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15
Inter plate earthquake
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ArchCapital A
SinkingSmile
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PrimaryPush PullPulse
SecondarySide Side
P WaveS Wave L Wave
Richter Quake Strength Mercalli Damage
XII
Each number increase wave height increases by 10
Energy released increases 30 times
Rocks can only hold energyup to +9.0 Richter intensity
Today = Moment Magnitude combines Richter measure and actual ground movement
9.5
Only travelthrough solids
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P WaveS WaveL Wave
Difference in arrival time P vs S waves = 1 min 40 secFor every second that P and S differ = 9.75 km100 sec X 9.75 km = 975 km
975
975
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Inner CoreIron / Nickel Solid
Outer Core
Mantle
Crust
P waves
S waves
Slow in Mantle, Outer Core, Speed up Inner Core
Slow in Mantle , Stop at the Outer Core
Shadow Zone= where no seismic waves are detected
Rigid Solid Silly PuttyFlexible Solid
Molten Liquid
Seismic Gap = location that has not had an earthquakein a long time
A
BC
A
B
C
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P Wave S Wave
Anticline
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