Plate Tectonics Vocabulary Inner core Mantle Outer core

Plate Tectonics Vocabulary ü ü ü ü ü Inner core Mantle Outer core Crust Asthenosphere Epicenter Composite volcano Laccoliths Neck Batholith Viscosity Seismic wave Continental Margin Tectonic Plate Transform Boundary Subduction Convection Lava Seismograph ü ü ü ü ü Converging boundary Diverging boundary Subduction Fault Lithosphere Plate tectonics Spreading centers Earthquake Sill & Dike Strike slip fault Moho S-wave P-Wave Reverse Fault Normal fault Mid-Ocean Ridge Oceanic trench Slab pull Ridge push This Photo by Unknown Author is licensed under CC BY-SA-NC

Take a sticky note and count the number of stamps from the Astronomy vocabulary to the Solar System CER (Max 7). Place name and sticky note on your composition book and place composition book on front lab station.

Structure of the Solid Earth (Draw into your notes including numbers) Structure of the Solid Earth ? Crust: 10 Km Thick at ocean basin, up to 75 Km at mountain tops Outer Core: 2250 K m thick What Causes the layers? ? ? A. Density Differences, B. Temperature differences. C. Materials Mantle: 2900 KM thick Inner Core: 1200 Km thick

1. Crust: solid rock, includes dry and wet land. 2. Mantle: hot & semi solid rock a. Lithosphere: Upper, rigid part of the mantle 1. ) Moho: boundary between the crust & mantle b. Asthenosphere: upper most portion of mantle, semi liquid layer

Moho

3. Core: made up of mostly metals, very hot! a. outer core: liquid metal b. inner core: solid, dense metal https: //app. discoveryeducation. com/learn/videos/f 0 eaeb 1 e-5 ff 2 -4 a 91 -b 421 -91908 ba 17728? has. Local. Host=true https: //app. discoveryeducation. com/learn/videos/3 AF 35 E 7 F-8035 -4 D 67 -9697 -FC 46 D 147757 D? has. Local. Host=true

Seismic waves: A can. s ve core a snap shot of inside : which wgh the te throu o N el the earth v tra • Waves travel at different speeds through liquids & solids. (Also different types of minerals) Due to this we can see the differences of materials within the earth.

Meteorite: Clues to the core. • Show similar metals to what we believe the core is made of!

How do these contribute to the Planet? • Crust- surface, cool place for life to live. • Mantle-viscosity allows plates to move, convection currents within drives plate motion. • Outer core- Helps heat up mantel, low viscosity absorbs certain seismic waves. • Inner core- Super dense materials produce electromagnetic field. Internal energy source.

CER Reading assignment: 308 -316 Research and Analyze the following. What does the Auroras and the needle from a compass have in common? How do these support our current understanding of the earths interior?

WHAT IS CONTINENTAL DRIFT?

Let’s Review! a. transfer of heat through liquids and gases due to temperature and density differences. = convection b. transfer of heat by physical contact = conduction c. transfer of heat through waves = radiation

Continental Drift Theory. Alfred Wegener- German Scientist, Wegener purposed that all continents were once joined together in a single landmass & then have slowly drifted apart. He called his super continent …Pangea

a. Theory is called: Continental Drift b. 1 st formed Pangaea “super continent”

The Evidence…. He first noticed that the continents seem to fit together. 2. Look at the fit of South America’s east coast and South Africa's west coast. 1.

More Evidence. 1. Similar landforms a. Mountain ranges of S. America & Africa line-up b. coal fields of N. America & Europe line up

More Evidence. Fossils- similar fossils found where landforms match. I. E Mesosaurus

. Another piece of evidence Continent’s climates have change when the land drifted. What are some clues one might find of past climate?

Lots of evidence that supports CD but did people believe him? https: //app. discoveryeducation. com/lear n/videos/F 27 A 9477 -F 56 C-4009 -A 89 B 6 AE 7 AB 2 CAA 39? has. Local. Host=true

Wegener’s hypothesis was rejectedcouldn’t explain why the continents move. The answer we now know = Convection currents caused by our core. Convection box demo

Modern day Evidences.

Sea-floor Spreading 1. Mid-ocean ridges (MOR)- sea floor spreads & new ocean floor is created.

East Pacific Rise & Others Underwater Earth quakes along these areas show boundary lines.

Magnetic polarity

Polar Reversals Late 1950’s began mapping the ocean bottoms Sonar, gravity and magnetics Magnetic data showed odd phenomenon Appeared to be striped Polarity reversal were identical on each side of oceanic ridge 1960, Harry Hess proposes seafloor spreading Confirmed by mini-Submarine Alvin in 1960’s

Reversed magnetism seen in Rocks.

Final Proof… The age of the ocean bottom. 1968 United State Geologic Survey (USGS) Deep sea drilling w/ Glomar Challenger Drilling showed the age correlation in ocean floor rocks. Where do you think the oldest rocks are located on the sea floor? Youngest?

What's happening at the other end of the sea floor spreading centers? ? 3. Subduction- process of the ocean floor sinking back into mantle a. Deep-ocean trenches- deep water canyons in ocean

Sea-floor Spreading MOR-New ocean crust Subduction Melting Asthenosphere

Science Exercise: Answer the following questions in your composition book…. Textbook pg. #307 1 -4.

Quiz - Earth Structure. A. B. C. D. E. F. G. Asthenosphere Inner core Mantle Lithosphere Crust Outer Core Moho

Quiz - Layers of the Earth 7. What Layer of earth is the most dense? A. Outer core B. Inner Core C. Mantle D. Crust 8. What is the basis for the division of Earth’s layers? A. Composition B. Color C. Density D. Temperature 9. Which layer of the Earth is liquid? A. Mantle B. Inner core C. Atmosphere D. Outer core 10. Which layer is the least dense. A. Atmosphere B. Crust C. Inner core D. Mantle 11. Which layer of the Earth is the thickest? A. Mantle B. Crust C. Outer core D. Atmosphere. 12. True or false, We don’t have the technology yet to reach the mantle. A. True B. False 13. Name the 3 pieces of modern piece of evidence for continental drift. 14. What does MOR stand for?

C A D 15. Where in the diagram above are the youngest rock material at the MOR? 16. Where in the diagram above are the oldest rocks? 17. What earth process allows plate tectonics to work? 18. What is a converging boundary? 19. What is a divergent boundary? 20. What is a transform boundary?

Is there other evidences? YES! https: //www. youtube. com/watch? v=DLw. JT_igmls

CER Read and take notes on pages 308 -316 of your text. Let me stamp your notes when they are completed. Research and Analyze the following. What does the Auroras and the needle from a compass have in common? How do these support our current understanding of the earths interior?

What is the following picture?

Pacific Plate North American Plate

Earths Plates n n Separated by faults Fault – a break or crack in Earth’s crust along which movement occurs Frequented by earthquakes and volcanos 3 boundary types n n n Transform Divergent Convergent

The Crust is broken into plates.

How many plates? 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Eurasian Indian Pacific Philippine Cocos Nazca Antarctic North American South American Caribbean African Arabian Juan de Fuca -Small Scotia Fiji- Small Austrailian

What the plates are made of. Primarily Igneous rock. n Granite –continental crust- continentsn n n Less dense Basalt- oceanic crust- ocean floor. n More dense

Transform Boundary n n A place where crust is neither created or destroyed Plates slip by each other Plates move in opposite directions Frequented by numerous Earthquakes.

Divergent Boundaries n n Place where two plate move apart Most occur at mid-ocean ridges Primarily responsible for sea-floor spreading Rift valley – divergent plate movement that occurs on land by the pulling apart of a continent.

Divergent Boundaries: & Rift valleys Mid-Ocean Ridge

Rift valleys form from forces underneath.

Convergent Boundaries n n n Where two or more plates move toward each other Results is a collision 3 Types n n n Oceanic with continental crust Continental with continental crust Oceanic with oceanic crust

Convergent Boundaries n Continental with Continental Results in n n Mountain building Himalayas Mountains – collision of Indian and Eurasian Plates.

Convergent Boundaries n Oceanic w/ Continental Results in n n Subduction – converging boundary where one plate is plunging under another plate Trench forms at boundary between the two and volcanic mountains http: //www. youtube. com/watch? v=wkc 4 lbh h. SRs

Convergent Boundaries Oceanic with Oceanic Crust n Trench plus development of Island Arc System n Island Arc – ex. Aleutian Islands of Alaska. n

CER - What are some evidences that the earths surface is broken into different plates? CER - How do you think maps of tectonic plates have changed over time? In what ways? How might they be different 100 years from now?

Volcanic Eruptions and Hazards

What is a volcano? vent • cone conduit A volcano is a vent or 'chimney' that connects molten rock (magma) from within the Earth’s crust to the Earth's surface. • The volcano includes the surrounding cone of erupted material. magma chamber

How and why do volcanoes erupt? • Hot, molten rock (magma) is buoyant (has a lower density than the surrounding rocks) and will rise up through the crust to erupt on the surface. Same principle as hot air rising, e. g. how a hot air balloon works • When magma reaches the surface it depends on how easily it flows (viscosity) and the amount of gas (H 2 O, CO 2, S) it has in it as to how it erupts. • Large amounts of gas and a high viscosity (sticky) magma will form an explosive eruption! – Think about shaking a carbonated drink and then releasing the cap. • Small amounts of gas and (or) low viscosity (runny) magma will form an effusive eruption – Where the magma just trickles out of the volcano (lava flow).

Explosive Eruptions • Explosive volcanic eruptions can be catastrophic • Erupt 10’s-1000’s km 3 of magma • Send ash clouds >25 km into the stratosphere • Have severe environmental and climatic effects • Hazardous!!! Mt. Redoubt Above: Large eruption column and ash cloud from an explosive eruption at Mt Redoubt, Alaska

Explosive Eruptions • Three products from an explosive eruption – Ash fall – Pyroclastic flow – Pyroclastic surge Pyroclastic flows on Montserrat, buried the capital city.

Direct measurements of pyroclastic flows are extremely dangerous!!!

Effusive Eruptions • Effusive eruptions are characterised by outpourings of lava on to the ground. Hawaii Courtesy of www. swisseduc. ch

CER. What controls the violence of an eruption? How fast is magma ejected out of the volcano?

Volcano Monitoring and Hazard Mitigation

Volcanic Fatalities • 92, 000 Tambora, Indonesia 1815 • 36, 000 Krakatau, Indonesia 1883 • 29, 000 Mt Pelee, Martinique 1902 • 15, 000 Mt Unzen, Japan 1792 Courtesy of www. swisseduc. ch But, volcanoes cause fewer fatalities than earthquakes, hurricanes and famine.

Volcanic Hazards • • • Courtesy of www. swisseduc. ch Pyroclastic flow Lahars/Mud flows Pyroclastic fall Lava flow Noxious Gas Earthquakes

Pyroclastic Flow • For example, eruption of Vesuvius in 79 AD destroyed the city of Pompeii

Pompeii (79 AD) On August 24, 79 AD Mount Vesuvius literally blew its top, erupting tonnes of molten ash, pumice and sulfuric gas miles into the atmosphere. Pyroclastic flows flowed over the city of Pompeii and surrounding areas.

Pompeii (79 AD) Pyroclastic flows of poisonous gas and hot volcanic debris engulfed the cities of Pompeii, Herculaneum and Stabiae suffocating the inhabitants and burying the buildings.

Pompeii (79 AD) The cities remained buried and undiscovered for almost 1700 years until excavation began in 1748. These excavations continue today and provide insight into life during the Roman Empire.

Vesuvius today • Vesuvius remains a hazardous volcano with heavily populated flanks: Naples Vesuvius Bay of Naples Courtesy of www. swisseduc. ch – around 1. 5 million people live in the city of Naples alone – Naples is situated approx. 30 km from Vesuvius – Pyroclastic flows can flow up to 100 km from source!

Mt Peleé, Martinique (1902) • An eruption of Mt Peleé in 1902 produced a pyroclastic flow that destroyed the city of St. Pierre. before after

29, 000 people died…. Only 2 survived! Why?

CER - How do pyroclastic flows cause devastation?

Pyroclastic Flow - direct impact Courtesy of www. swisseduc. ch

Pyroclastic Flow - burial

Pyroclastic Flow - burns

Pyroclastic Flow - lahars • Hot volcanic activity can melt snow and ice • Melt water picks up rock and debris • Forms fast flowing, high energy torrents • Destroys all in its path

Pyroclastic Fall • Ash load – Collapses roofs – Brings down power lines – Kills plants – Contaminates water supplies – Respiratory hazard for humans and animals

Lava Flow • It is not just explosive volcanic activity that can be hazardous. Effusive (lava) activity is also dangerous.

Lava Flow - Heimaey, Iceland • Iceland, January 23, 1973. • Large fissure eruption threatened the town of Vestmannaeyjar.

Lava Flow - Heimaey, Iceland • The lava flows caught the inhabitants by surprise • Before the eruption was over, approximately onethird of the town of Vestmannaeyjer had been destroyed

Lava Flow - Heimaey, Iceland • However, the potential damage was reduced by spraying seawater onto the advancing lava flows. • This caused them to slow and/or stop, or diverted them away from the undamaged part of the town.

Practical Exercise 2. Assessing Volcanic Hazards

So…. How do we minimize the risk of active volcanoes?

Volcano Monitoring Volcano Observatories are set up on all active volcanoes that threaten the human population. These are designed to monitor and potentially to predict the eruptive behaviour of the volcano in question.

Volcano Monitoring • Seismicity • Deformation • Gas Output – (on volcano and remote sensing techniques) These three things are the most important precursors to an eruption.

Seismic Activity • Earthquake activity commonly precedes an eruption – Result of magma pushing up towards the surface – Increase volume of material in the volcano shatters the rock – This causes earthquakes

Seismic Activity • Earthquake activity is measured by Seismographs – Seismographs are stationed on the flanks of the volcano – These record the frequency, duration and intensity of the earthquakes and report it back to the volcano observatory.

Deformation Monitoring • “Tiltmeters” are used to measure the deformation of the volcano – The tiltmeters measure changes in slope as small as one part per million. A slope change of one part per million is equivalent to raising the end of a board one kilometer long only one millimeter!

Deformation Monitoring • Tilltmeters can tell you when new material enters the magma chamber. A B Note the presence of earthquakes in relation to the deformation. Often it is a combination of events that fore -warns of an eruption.

Gas Monitoring • Commonly gas output from a volcano increases or changes composition before an eruption. – As magma rises to the surface it releases (exsolves) much of its gas content. – This can be measured

Gas Monitoring • Gas samples are collected from fumaroles and active vents. • Gas levels may also be monitored by remote sensing techniques

In Summary. . • Volcanoes are extremely hazardous. • However, the volcano can be studied, monitored and understood. • Each volcano is different, and offers a unique set of dangers • Plans may be emplaced to help control potential damage.

Noxious Gas • 1, 700 people living in the valley below Lake Nyos in northwestern Cameroon mysteriously died on the evening of August 26, 1986.

Noxious Gas • • • Lake Nyos is a crater lake inside a dormant volcano. The lake had become laden with carbon dioxide gas. This gas had suddenly bubbled out of the lake and asphyxiated nearly every living being in the surrounding valley.

Noxious Gas • A management plan has been developed to remove gas from the lake to prevent a further tragedy. • An artificial vent to the lake surface was created with pipe. • Water is pumped from the bottom of the lake to the surface through the pipe, where it can degas.

Noxious Gas

Noxious Gas

Noxious Gas • The Lake Nyos incident was not unique. • Two years earlier, Lake Monoun, 60 miles to the southeast, released a heavy cloud of toxic gas, killing 37 people. • A third lake, Lake Kivu, on the Congo. Rwanda border in Central Africa, is also known to act as a reservoir of carbon dioxide and methane, which is a valuable natural gas that is gathered from the lake and used locally.

Earthquakes • Large volumes of magma moving through the shallow crust can cause large earthquakes. • This can lead to building collapse, slope failure and avalanches

Earthquakes Destruction after a volcanic induced earthquake in Japan