Plate Tectonics â rigid âskinâ of the earth in ... Geo = earth, logos = speech, study, science ...... chemical ppt. is accumulating on the ocean floor or on land.
EARTH SCIENCE Geology
Chile
Mt. Unzen, Japan: 1991
Old volcano
Mt. Rainier: next one to erupt?
Black smokers: at bottom of the sea along a rift
Earthquakes in Canada
Quest for gold
Magnetic Fields on the Sun
Objectives • Composition of the Earth • Should be able to identify every rock you pick up • Or at least you will know HOW to go about identifying it • A bit of the Earth’s history and the power that drives volcanoes and earthquakes
Manitoba Geological map: available to all who ask for it
Canadian Shield
World tectonic map
New theories • Plate Tectonics – rigid “skin” of the earth in constant motion (but very very slow) • Dinosaurs existed & numerous other creatures • Ice Ages, all Canada covered until recently • Periodic asteroid hits that wipe out living forms • Mountains are created & later destroyed by erosion
Dark areas: rifts with volcanic mountains
Earth science • Necessary to see how “the Earth works”, esp. now with climate change (Earth under stress?), repair damage, be active to protect, teach with examples, go on field trips • Hurricanes (some human factor), tsunamis (not frequent, but always happen), volcanoes (deadly, but life-giving)
This course: Geology • Geo = earth, logos = speech, study, science All scientific words are Greek • (Weather is part of Geography)
What we study • Make-up of Earth, volcanoes, earthquakes • 2 Labs. on Minerals, 3 labs on the types of Rocks (igneous, sedimentary, metamorphic) • Examples of minerals: salt, diamond, graphite • Examples of rocks: limestone, granite, basalt
New theory
Earth has a secret!
Energy inside earth? Yes! • Responsible for events like : volcanoes, earthquakes, geysers, slow movement of crust that creates mountains (at a rate of a growing finger nail) • Theory of the origin of the earth : explains energy “trapped” in the interior
How did it all start ? • Gas and dust particles floating in space from previously existing stars that died and blew up • Particles accumulate by gravity • Particles trying to get into the center eventually swirl like in a hurricane • They combine, heat up (gravity turns to heat) and form a new star • Left-over particles form the planets • All planets continue to move around the star
• When a star larger than the sun exploded as a Supernova (most intense furnace the universe can provide) • Heat of impact and the much greater heat of radioactive decay melted the rocks • Earth moves at 30 km/sec • Most objects on solar orbit move at 20 – 50 km/sec relative to Sun
A galaxy
Sun: a nuclear factory, all molten
Someone spent 80 days refueling at 5,500 degrees Celsius (2012)
Theory on the Origin of Earth • Stages : 1. dustball 2. fireball 3. differentiation by density 4. cooling 5. later changes (life forms change, mountains form)
• Layers found on earth: atmosphere crust (ign/sedim/meta) mantle core
age origin • Universe
13.7 b.y.
• Solar System
future
explanation
Bing Bang all stars move away
4.6 b.y. nebula
dust+gas
expansion
explodes
-----------------------------
• Star : is born - burns gas - dies when runs out of gas
All ends in a black hole
“Dating” rocks • Radioactivity discovered early in 1900’s accidentally by Madame Currie of Paris • A radioactive element like uranium decays at a constant rate to form lead. During the decay, it releases electrons, protons and powerful gamma rays, detectable with a Geiger Counter (scintillometer) • The ratio of U / Pb in the rock (extremely low concentrations) would be proportional to the age of the rock
• Plate Tectonics : 30 year old theory • Heat rises under thin ocean & lava spreads • Moving plate collides with another plate & subducts • All surface in constant motion • Geologic processes take place slowly with the speed at which fingers nails grow (a few cm/year • Geologic time is enormous
Subduction
Organic Evolution: Life on this planet is marine in origin . Ingredients may have come to this planet from comets, meteorites • First life in black smokers (still around today) • Photosynthesis (plants like bacteria) later • Single cell plants(first) & animals (later) • Invertebrates (no hard parts, later skeletons) • Vertebrates: Fish, first vertebrate • Amphibian, reptile(some warm-blood), mammal, bird • Homo sapiens emerged from the Ice Age
Life • Invertebrates: most abundant life on the planet, includes insects, clams, snails, etc • Have external skeleton • Vertebrates invented later to be able to travel in the sea (originally) • Conditions were good for life to move onto land about 400 m.y. ago (ozone layer formed) • It took 4 b.y to build the ozone, but only 50 years for humans to destroy it partially (freon)
Life • Fish to amphibian was a relatively simple transition • Amphibian to reptile (100 % land animal) was a big step • Reptiles made tremendous advances, like the amniotic egg, warm blood, teeth for chewing • These were passed on to the mammals, such as us • We are grateful to the dinosaurs for all these advances (Hollywood will never teach you these simple facts, because the producers are NOT educated)
Life • On this planet life is Carbon-based with sulfur, nitrogen, etc: all products of volcanoes • In other words, life was created by the ingredients that are emitted by volcanoes • Most volcanoes are under the sea, so life started there • Life elsewhere in the universe maybe different, such as silicon-based (reportedly, the “grays”) • Reproduction was by division (offspring identical to parent), then branched out into sexual reproduction from about 1.5 billion years ago
Life • The life on this planet maybe very rare in the universe • Judging by the interest shown by other civilizations – the media obscures “strange” events, such as crop circles & flying saucers because they think most people are stupid • You can ask the astronauts about the strange events they encountered. That is why no one wants to fly to the moon again!
Scientific method in all sciences • Observe and make an explanation (hypothesis, theory, law) • Uniformity (“the present is the key to the past”): only law in geology • Once in a while dramatic disruption of life by the fall of an asteroid (large meteorite) • Earth is a closed system (can’t export pollution)
Now • Humans have been able to change the planet’s atmosphere & kill off some of the ozone layer (protective layer from UV radiation of the sun) • Need to repair damage or face the consequences • Have to protect the environment (it is “our only home”, some of my students wrote in essays/projects)
Meteorites • They fall from the sky coming from the Asteroid Belt (between Mars and Jupiter) • Most have been unchanged since the formation of the Solar System • They contain information about the origin of the Solar System • They are very valuable and are worth a lot of money (at least $ 10,000) to whoever finds one • Meteorites are named after the nearest community in which they fall or are found (they are called “finds”) • Rarely, a meteorite is seen to fall (a “fall”) • Only about 70 have been found in Canada, so start looking
Russia, Febr. 2012 injured 1200 people
9 months later: found at the bottom of the lake
The biggest known fall: Sikhote Alin
2001, near Winnipeg
Tom Wood, near Winnipeg
14-year old hit in the foot
The “eye of Quebec” Manicouagan crater
2008 fall
Science of meteorites • Fascinating facts about them • Their speed: min. of 11 km/sec up to a max. of 70 km/sec. Average 30 km /sec (2 sec to Wpg) • Worth at least $ 10,000 and you still owe it! (in Canada) • Analysis can give information about birth of our Solar System
This little rock was part of the killer asteroid
Ash left from the dino killer
Manitoba craters • Gypsumville (St. Martin): biggest in western Canada, 40 km across • West Hawk Lake (near Ontario border): It is 100 m deep with another 100 m of mud and 330 m broken up rock (only ~2 km diameter) • A BUNTEP student found a small crater in his trap line (the third in Manitoba)
Comets (usually 1 tail or two, this one has 6!)
Comet Shoemaker-Levy 9 hit Jupiter in 1994
Video: The Miracle Planet • • • • • • • • •
Origin of the solar system Meteorites on earth: Chicago Murchison meteorite: water, aminoacids Manicouagan (The “eye of Quebec”) Planetesimals, Bombardment, Fireball First rain K/T boundary, clay with iridium Mexico meteorites Famous 1972 “near –miss” or “fly-by”
Video: The Heat Within • • • • • • •
Yellowstone Witwatersrand, 3 km deep mine, temp. at 52 degrees C Iceland : famous for its volcanoes, not for its ice! 1974: started exploration of the ocean floor Black smokers East African Rift: valley with hot springs, geysers, volcanoes Himalayas: rocks up the mountain are made up of fossils, they formed in the sea and were elevated by the collision of the continents • Purification of minerals : Cu in Cyprus • Andes 8,000 km long: “copper mountains”
Geological History of Manitoba • In poster form
Geological History of Manitoba
Minerals
MINERALS (not rocks!) • 92 chemical elements • Made of atoms: smallest possible unit. Can be seen under 17X million magnification • “Atom” means “ Impossible to split” • However, it became possible during WWII when the Atom Bomb was created (mass turned into energy)
• Electrons (the word means “amber” because it can be electrified by rubbing on clothing) occupy specific orbits around the nucleus • Most of the atom is empty space, like the universe or Solar System If less than 8 electrons in the outermost orbit, substance is unstable, forms compound. Types of chemical bonds: • covalent (diamond), ionic (salt), metallic (copper), van de Waals (graphite)
• If outermost orbit has 8 electrons, the element is stable and can exist by itself • Examples copper, silver, gold • These are called native elements
Diamond • • • •
Has many unique properties It is the hardest known substance It is made up of just carbon (like graphite) However, it is the atom bonding that is different, the way the atoms are bonded together • Diamond has 4 electrons on its outer orbit which are shared with 4 other atoms by an extremely strong bond • In graphite, groups of carbon atoms slide easily past other groups. They form under lower pressure than diamond
Looks like glass, but it is heavy
Crystal structure of diamond
Super-explosion of a volcano with diamonds
Diamonds measured in carats • Name is keration= fruit-like shape of pods • Here are samples of carats • The pods in a chocolate bean (carob) found in Greece – makes herb chocolate, chips as well • Each pod weighs exactly 0.2 gram • Used as a measure of weight for gems (not for gold anymore)
Gypsum crystals, Mexico
Museum changed appearance
Natural, solid, inorganic, unique structure/composition: Definition • • • • • • • • •
Crystal (“ice”): solid form Color, streak (plate, hematite), luster cleavage, fracture (conchoidal) hardness (Mohs) S.G. = wt/ loss in wt, or equal volume of water Graphite 2 water= 1, most rocks = 2.6 Diamond 3.5 Silver 10 Gold 19 platinum 21
Miscellaneous • • • • • •
Acid test: calcite / dolomite Magnetism : magnetite / pyrrhotite Taste : halite / potash Double refraction : calcite Twinning : plagioclase Elastic : only micas
Glass breaks like that, also quartz
Hematite: bloodstone, it bleeds when scratched, but does not cry
Aboriginal art in rock near Norway House
Amethyst (Can’t get drunk)
sapphire
Specific gravity / Archimedes principle or Law of buoyancy 1. 2.
3. 4.
King Hieron gives a jeweller a bar of gold to make into a crown When the crown was delivered, the king measured the mass. It had the same mass as the gold bar The king is suspicious. He asks Archimedes. A. notices that the amount of water that overflowed the tub was proportional to the amount of his body that was submerged
No one knows about density then Archimedes reasoned that 1. If the gold bar and the crown had the same mass, and 2. If both had the same volume, Then, the crown was pure gold
Density = weight in air / loss in weight when immersed in water or, weight of water displaced
Archimedes reasoned that The volume of water displaced by the crown should be the same as the volume of water displaced by the bar of gold However, the crown displaced twice the amount of water than the gold bar(it had lower density, consisted of less dense material)
• Water displacement: an object immersed in water will displace a volume of water equal to the volume of that object • Water Bridge: A ship always displaces an amount of water that weighs the same as the ship
The water bridge, Germany: a ship displaces an amount of water that weighs the same as the ship
Archimedes screw • Used to bring water up from the river • Essential for irrigation in Egypt & elsewhere
Other inventions: Mirrors
Earth’s crust • • • •
98.5 % made up of only 8 elements 75 % of these are OXYGEN, then SILICON Rest are Fe, Mg, K, Na, Ca, Al Most common compounds are Silicates, or rock-forming minerals • Basic unit : 1 Si, 3 O atoms
SILICATES units mineral crystal form color • • • • • • •
Isolated Olivine granular green Single chains pyroxene long crystals green Double chains amphibole long black/green Sheets micas layers various 3D quartz like boxes various orthoclase ‘’ “ pink/white plagioclase “ “ white/black
Major Elements in Silicates & their symbols
• • • • • •
Iron Fe Magnesium Mg Sodium Na Calcium Ca Potassium K Aluminum Al
Elements in Silicates • • • • •
Olivine Amphibole, Pyroxene Micas Orthoclase Plagioclase
Mg Fe Mg Fe K, Na, Ca K Na, Ca
Typical question on minerals • This white, soft mineral has glassy luster, basal cleavage, white streak and is used in wall construction. a) quartz b) calcite c) gypsum d) epidote e) pyrite
Previously melted
IGNEOUS ROCKS • 80 % of all rocks, used to be molten • Magma : molten silicates + gases + metals • All gases (except oxygen) & all metals come with magma • Geothermal gradient : 30 ‘ C / km of depth • Entire interior should be molten, but no room • Any movement below ~ 35 km creates magma
Centigrade (Celsius) scale • Metric (French, brought from Egypt by Napoleon) • Water freezes at 0 degrees • Water boils at 100 degrees • Divide scale into hundred divisions • On that scale magma melts at ~ 1,000 degrees • Our body temperature is 36.6 degrees • So, keep away from magma !!
Hypothermia •
• • • • • • • • • • • •
Erika Nordby, Edmonton, 2001
Karlee Kosolofski, Rouleau, Sask. 1994 Brittany Eichel, W.Virg. 1991 1 year-old 2 year old 3 year old Toes frozen together tried to follow her dad to work 2.5 hours at – 3 ‘ C Outside for 3-4 hours winter coat + boots over pyjamas only underwear Took doctors 1 ½ hours to get found 6 hours later at – 22’C lost a toe the heart beating again body almost frozen solid slowed metabolism enough legs were frozen like blocks of ice it didn’t need normal blood flow left leg amputated, bone surgery, skin grafts 14 ‘ C : lowest ever recorded Hypothermia made first heart transplant possible Wilfred Bigelow (Brandon) in 1950 found how to safely lower the body’s need for oxygen by lowering the body’s temperature. Also developed the first pacemaker. Revolutionized heart surgery which is routine operation today.
Magma chamber • When melting takes place, less dense magma rises, denser sinks • Near the top of chamber, water vaporizes expanding as it does. This exerts upwards pressure, as soon as it is strong enough, blasts overlying rock • The pressure inside chamber suddenly reduced, allowing magma to expand and flow up the newly made opening
Magma cools • Interior : intrusive, plutonic • Exterior : extrusive, volcanic • TEXTURE: size of crystals - small crystals means it cooled quickly - large crystals means it cooled slowly - glassy means extremely fast (that is how window glass is made)
Crystallization of magma • When temperature drops • Olivine : first to appear (lowest in silica) • Followed by other dark minerals (pyroxene, amphibole, Ca-rich plagioclase, biotite) • Followed by light colored minerals ( Na-rich plagioclase, orthoclase, muscovite) • Quartz: last to crystallize
Crystallization of magma (Bowen) • Impossible to have olivine and quartz in the same rock • Igneous rock would have - high temperature minerals - intermediate temperature minerals or - low temperature minerals Can’t have them all in the same rock !
Crystals twinkle in the sunshine • Especially the micas • People think they are gold! • They certainly reflect almost like gold
Porphyry • Originally, the “purple dye” taken from some clams in the eastern Mediterranean • Red or purple color • Byzantine Emperors were dressed in red or purple color • Red or purple columns of porphyry in great demand during the early years of Christianity, reserved for the first churches. Found only in one place in the Egyptian desert
Saint Sophia, Constantinople (Istanbul)
Orbicular granite from Chile
Pegmatites : rare • • • • •
Extremely slow cooling of magma Crystals accumulate in layers Beryllium (emeralds)- Dryden, Ont. Platinum: only mine in S. Africa, for seat belts Titanium: 1st find in Cross Lake, for zippers, tennis rackets, bicycles, airplanes, paints, etc • Chromium: for car bumpers, etc • Vanadium: for making steel
Pegmatites • Many in SE Manitoba • Mine at Bernic Lake (near Lac Du Bonnet) • Produces unusual metals like - lithium: for batteries, stomach pills - cesium: for accurate clocks, electronics see also Cesium festival - tantalum: for bone repairs - columbium: for electronics
Cesium flame
Pegmatite
Classification of igneous rocks • Based on texture & minerals present • Light colored – intermediate – dark • Commonest : granite (makes continents) & basalt (makes the ocean floor) • Rare on surface: Ultramafic, makes up the mantle (basically, olivine + some diamonds)
Granite : very hard rock
Trango Tower, Pakistan
Cooling of mafic (black) magma • Arrives at the surface uncontaminated • Same composition as upper mantle • Oceanic crust: none older than 600 my has been found – it gets recycled • Polygonal columns (at 90 degrees to cooling surface) • pillows
Giants Causeway, N. Ireland basalt
Columnar jointing in basalt
Peridotite • Most common in the Solar System • Contains olivine and other Fe Mg minerals
Shapes of intrusions • • • •
Thin : dike or sill Laccolith : mushroom shaped Volcanic pipe Pluton or batholith Other Features: • Chilled margins • Xenoliths
Sill and dike
Why granite so common? • Granite found only on Earth • No granite when Earth was created. Produced by plate tectonic processes • Contains small amount of radiation (uranium) Origin: Widespread melting during formation of mountains, collisions of continents and subduction of ocean floor • Every mountain has a core of granite
Earthquake today!
Magma to the surface: a volcano
Volcanoes • “Don’t kill people” • It is the people who get on their way • Respect it and move away until it is safe to go back • Its power is tremendous
Sulfur
Sulfur flame
Near a volcano
Looking down from above
Alaska
Volcanism • ~ 50 eruptions per year (on land) • Most volcanoes under the sea • Fissures along 70,000 km Rift system of ocean-spreading ridges-only place above water is Iceland • Also, volcanoes in subduction zones & • About 25 “hot spots”: Hawaii, Yellowstone, Galapagos, Iceland, many in Africa
Disaster v. Rebirth (Blessing) • Lava will burn, toxic gases will suffocate, etc • But, new rock, land, soil (very productive) • Gases: water, carbon, sulfur, nitrogen, halogens (Cl, F, I), noble (Ar, Ne, He) • Metals in black smokers (Au, Ag, Cu, Zn, Ni, etc) • Life (bacteria & invertebrates) • Diamonds
What comes out • Lava that flows or is sticky like honey • Stones of all sizes from ash to “bombs” • Gases (they make magma light & tends to move upwards) • Lava has cavities where minerals like amethyst and agates form, also, by special processes opal, turquoise
Mt. Unzen, Japan: 44 people trapped
The Blue Lagoon, Iceland
Sand baths
Vesuvius, Italy
Volcanic sunsets
Composition of magma On continent On continent near ocean ---------------- --------------------------------rich in quartz some quartz rich in gases some gases light colored intermediate viscous (gases CAN BE EXPLOSIVE cannot escape) VERY EXPLOSIVE
On ocean floor -----------------low in quartz low in gases dark colored fluidy (gases can escape) NOT EXPLOSIVE
In mantle -----------no quartz no gases dark green ----
Landforms • Shield: flat, basalt, fluidy, aa, pahoehoe, pillow • Dome: steep, rhyolite, viscous (St. Helens) • Cinder cone: steep, rhyolite, pyroclastic, explosive • Composite: lava & pyroclastics (Mt. Fuji) • Caldera: crater, collapsed volcano (Toba, Crater Lake, Oregon)
pahoehoe
Aa!
Basalt pillows under the sea
Accumulate on the ocean floor
Can be found on the surface: these are pillows from the Archean, 2.8 billion years old
Columnar joints
Effects • Lava flow predictable – throw water to it! • Pyroclastics: dangerous, ash + stones + gases all hot : Nuee ardente (pyroclastic flow) heavier-than-air, flows downhill at 100 km/h • Martinique, 1904: 40,000 died + 1 survived • Pompei, 79 AD: gypsum bodies • Hot ash mixed with rain or melting snow= lahar, like cement—Armero 1985
Nuee ardente
Effects cont. • Phreatic eruption: Krakatoa 1883 magma + sea water→ superheated water, extr. Violent • Tremendous noise to Africa, Australia (deaf) • “Atlantis” (Santorini), 1650 BC destroyed Minoan civilization- no skeletons, gold, therefore people escaped & went to America (?) • Gases only: Africa, 1986 CO2 escaped from lake suffocating people-animals
Santorini
Santorini people leaving town
Gypsum casts- Vesuvius
bread
Nearest volcano to Manitoba
Devil’s Tower, Wyoming
Unexpected benefits
Prediction • • • •
Rhythmic tremors Unusual animal behavior Hot springs, smoking Sulfur gases indicating magma
Summary for Mid-Term • Creation of Earth, Life forms over the ages • Minerals and how to identify them by their physical properties (Labs 1 & 2) • Igneous rocks and how to identify them by their minerals they contain plus their texture (size of crystals) • Volcanoes (why are they a blessing), types and effects
• This red, hard mineral has either dull or metallic luster, brown-red streak and has been used as paint. It is not magnetic. a) magnetite b) calcite c) hematite d) pyrite e) garnet
Video: Mt. Pinatubo • June 12, 1991. It was asleep for 600 years! • Largest eruption of 20th century: 5-8 cu km of ash, that is 10 X that from St. Helen’s. Ash blocked sunlight for 5 years. Lahar deposits up to 200 m thick • Warnings: -frequent earthquakes -increase in gas emissions esp. sulfur -appearance of magma on the surface (a magma blob forming a small steep hill) Lahars from mixing of ash with rain from typhoon
Video: Forces of nature • • • • • • • •
Explosions of lava Hawaiian volcanoes: erupting since 1983 Pahoehoe: ropy Aa: crusty, sharp Pour water to stop lava Mt. Vesuvius, Pompei, 2,000 buried alive Martinique : pyroclastic flow 1980: Mt. St. Helen’s, mountain blows up, mudflow
Video: Deadliest volcanoes on Earth • Mt. St. Helen’s: eruption for 9 hours, geologist 9 km away did not survive • Mt. Rainier: dormant for 100 years, most dangerous in N. America • Mt. Unzen, Japan: pyroclastic flow coming down at 100 km/hour !
cont. • Indonesia: • Krakatoa, 1883 (24X nuclear blast) killed 36,000 by tsunamis, 1925.Made people deaf . Golongo . Tambora, 1815 (“year without a summer”), cold weather, famine . Toba, 75,000 years ago a global catastrophy that reduced human population from 700,000 to 10,000. Finding supported by DNA evidence: this disaster is the reason why humans are only one species today
cont. • A big eruption throws lots of dust into the air blocking the sun • A nuclear winter scenario • Temperature drops, crops fail, massive famine • Where will the next big eruption be? • Mexico City, Montserrat, or in your own backyard?
St. Pierre, Martinique, 1902 a sequence of events • • • • • • • •
Early April : smoke April 23 : cinders April 25 : rocks & ashes May 2 : pillar of dense black smoke falls like snow May 4 : ash rain, very dense. Lost electricity May 5 : explosion louder than thunder May 7 : Two fiery craters glowing like blast furnaces. Dark ash cloud May 8 : 7:52 am: Enormous column of black smoke moved incredibly fast. It filled the whole sky. It became dark. Cloud reached town in less than a minute. Superheated steam and gases (“a glowing avalanche”) or nuee ardente exploded sideways
West coast volcanoes Mt. Meager
180 km N of Vancouver: hot springs Last activity 2,400 y. ago
Mt. Garibaldi
50 km N of Vancouver: landslides, last activity 13,000 y. ago
Mt. Baker (“sleeping giant”)minor eruption in 1870 Avalanche reached Vancouver 7,000 y. ago
Mt. Rainier Mt. St. Helen’s
most dangerous in N.A. last eruption in 1980 Mudflows reached 120 km away
Video: The Kraffts (Maurice & Katia) • • • • • • • •
Travelled 9 months/year for 20 years Kilauea volcano: lava lake in a depression Lungay, Africa: black lava like mud, very fluidy Indonesia: filmed nuee ardente in action, even at night Stromboli: frequent eruptions Heimay: cooled flow with water Indonesia: sulfuric acid lake, skin dissolved Armero: people did not trust volcanologists, but in Indonesia people evacuated & disaster averted
Video: Galeras • • • •
1993: 9 died inside caldera (6 scientists) Conference participants made an excursion Only 12 allowed to proceed down the caldera A tornillo registered after they left-did not know about it (had no safety equipment) • The reality is that their business is risky. They are willing to take risks for the benefit of science • Half a billion people live near active volcanoes
Video: Kilimanjaro, Tanzania • Tallest free-standing mountain at 4,600 m (above clouds) • Has its own micro-climate, with unique species of plants / animals. Soil is fertile from melting snow and supports a rainforest. Produces coffee & bananas. • Last eruption 300,000 years ago • Hot vent activity today, must be magma ~ 120m below. However, the glaciers on top are melting fast, 80% of icefield has gone. Maybe the rest will evaporate and the animal/plant life below will disappear
Video: Vesuvius National Geographic
• 50 eruptions since Roman Empire • Today, 2 million people live around the volcano. It is monitored • Pompei, 79 AD: people thought it was a mountain. Most fled. It was soft pumice rock to dig out, but in Herculaneum it was hard like cement. Romans were cremated, skeletons are rare. Only those trapped in Pompei, plaster was injected to make casts of the victims • Eruption had 2 stages: Ash & pumice for 18 hours first followed by the collapse of ash & pyroclastic flows entombed the people. The surges were most dangerous, violent like from a nuclear blast
Video: Vesuvius • Pliny the Elder wrote down the events • Was the biggest eruption for 4,000 years • 24 Aug. 79 AD 4 m of ash + pumice. Most people survived that. Magma turns into foam & magma around gas turns into glass. It fell at a rate of 20 cm / hour • There were forests on the mountain, it had not erupted for a long time (400 years) • Investigation discovered surges of pyroclastic flows. People died by suffocation, they had no injuries, there was a lack of oxygen. People had their mouth open upwards. Six surge layers were found. Surge # 4 killed most people at Pompei. It deposited a layer 5-10 cm thick like concrete. It formed with heat at 100 ‘C (no bacteria in the soil surrounding the bodies) with ash. It was like a jet blast.
cont. • 1997 in Monserrat: a pyroclastic surge killed 20 people – island deserted since • Final surge was at 8 am into Herculaneum. Pliny the Elder was found 2 days later. He looked as if he was asleep. • Probably 10,000 died in the countryside from the final surge • No excavations have been done outside Pompei, so the dead have not been found yet
Video: Lahars • Nyos: gas released from bottom of lake killed 1,700 people. Probably, a landslide triggered it. More gas in the lake now than before, like a time bomb. It is being pumped out. • Crater lake, Indonesia: sulfur is mined & is used to refine sugar and in medicines • Tangiwai, NZ: in 1953 a train disaster killed 151 people. A bridge was washed out by a mudflow.
cont. • Mt. St. Helen’s: hot mud rushed out at 80 km/h snapped a bridge on its way. • Mt. Pinatubo: 10 X than St. Helen’s. 350 killed by eruption. More than 200 lahars in the next 3 months. It is easy for the rain to start lahars from the unconsolidated ash. Dikes were built to channel the lahars • Mt. Rainier: “a disaster waiting to happen” 3 million people live on its flanks. In the last 10,000 years, 55 lahars have gone down the mountain as far as Seattle & Tacoma (1 every 200 years)
Video: The Ring of Fire • “Our Earth was born of Fire” • Volcanoes threw out the gases that formed air/sea • 400 volcanoes around the Pacific • Hawaii: volcanic lake • San Fransisco: 1906, 1989 (1.5 m slip) • Mt. St. Helen’s • Mt. Sikurajima, city of Sigosima, 1914 eruption • Japan: 50 volcanoes
cont. • Geothermal energy: health spas • Indonesia: 140 volcanoes, temple of Burabadur, sulfur miners • Bali: Ganun Lagun (sacred mt.) 1916 eruption • Hawaii: tallest mountain on earth (10 km) • In less than 1 year after eruption life emerges • Earth is alive!
St Helen’s eruption, 1980
May 18th, 1980 • • • • • • • •
Biggest eruption in modern times Largest landslide in recorded history Cascadia mountain belt Called “fire mountain” by the native Last activity 1857 First sign, an earthquake on March 20th Small explosion on Mar. 27 Brings curiosity to people
• • • •
Scientists (not specialists) started studying Harmonic tremors: magma on its way up “The bulge” formed on northern side May 18: earthquake under the bulge, caused landslide (avalanche) plus explosion 700 X bigger than atom bomb • Lateral blast (pyroclastic flow) overtaken landslide • Black ash made day into night
• Eruption pumped ash into the air for 9 hours • 57 people died
Ring of Fire • • • • • • •
400 active volcanoes around the Pacific Earthquake at San Francisco Mt. St. Helen’s 50 active volcanoes in Japan Budha temples at Borobudur, festivals Sulfur mined inside a crater Hawaii at the centre of the Ring
Video: Krakatau
Video: Santorini (Atlantis?)
It is breaking down
WEATHERING • Any rock exposed breaks down by mechanical / chemical means to form 1. Sediment + 2. solubles in water
• Life uses solubles to form skeletons & blood
MECHANICAL WEATHERING • Frost wedging: water expands into ice ~ 10%, it cracks rock/pavement. Tremendous power • Root wedging • Extreme temperatures • Wind • Exfoliation (pressure release) like onion skin Rock climbers know about this - Salt crystal growth
“Des Roches Extraordinaires”
Erosion : Siberia
Erosion : China
CHEMICAL WEATHERING • Water and acids (acid rain) • Products of weathering of silicates: mineral insoluble soluble olivine iron oxides (rust) Mg micas, pyroxene, iron,Al oxides,clays Mg,K,Ca,Na amphibole feldspars quartz
clays quartz ---------------remain on land
K,Na,Ca (silica) --------------into the sea
CLAYS (recently found on Mars as well) • a set of new minerals form as a result of weathering • Used in medicine pills (we eat clay in tablets) • Nutrients (that plants need) attach themselves to clays in the soil • We refer to clays as mud or dirt, esp. when wet & slippery • Clay is the basis of most fertile soils
ACID RAIN • Accelerates chemical weathering • Source is exhaust of all kinds of engines A. Carbon gases: from engines B. Sulfur gases: from engines C. Nitrogen gases: from heated up air around engines Trees die, lakes/sea become acidic. Fish die from eating colloidal Al oxides
SOILS • Depends on temperature & precipitation • Layered by action of water into A horizon : dark, organic-rich, zone of leaching B horizon: brown, zone of accumulation C horizon: broken-up rock with soil
Types of soils precipitation increases ---------------------------------------→----------------Laterite (red brick) thin A, clay-rich B+ Fe
Temp. Desert Prairie Increases over-fertilized thick A, clay-rich B, tall grasses up productive, if watered Chernozem short grasses
Podzol white A, in mountains
Tundra permafrost, immature
• Chernozem: means “black soil” in Russia, the largest expanse of it in the world covering Ukraine & southern Russia • Podzol: means “beneath ash” • Tundra: youngest of all soils, last region to be exposed from retreating glaciers. No organic matter, no true horizons. Acid, airless, peaty mud when permafrost melts
• Decomposition of organic materials produces humic acids, such as carbonic acid (CO2 from the oxidation of C on tissues that has dissolved in water) • It will react with carbonates to form bicarbonates, which are very soluble
Plants • Made of C,H,O • They remove from the soil: K,N,S,P, Ca, Mg, the “major plant nutrients” • The “minor plant nutrients” are Fe, Mn,Zn, B, Co + traces of Na, Cl, V, Si • Rains bring : N (from nitrate, ammonium), S (sulfates), Na, Cl (from the sea) • Nitrogen Cycle: when plants die, they decompose into ammonium compounds, some converted into N gas
Soil Productivity • Very valuable resource, need to prevent erosion by keeping roots in after harvest & erect “shelter belts” • Fertilizers needed to replenish it after use: Nitrogen: from ammonium sulfate, also from the air (if soil is broken up) Sulfur: from ammonium sulfate, gypsum Potassium: from wood ashes, potash (plants take K2O) Phosphorus: from manure, sewage, guano “ no animal or plant can exist without phosphorus”
Sedimentary Rocks • From products of weathering (2 types): - sediment (soil) -------→ Clastic sed. rocks - solubles ----------→ Chemical sed. rocks Lithification : 2-stage process 1. Compaction + 2. Cementation to form a sedimentary rock from sediment (long process) • Any sedimentary rock may contain fossils (most abundant life is microscopic, so are their fossils)
Grand Canyon
Fossils
Corals are animals
Always, spectacular colors
Trilobites, now extinct
Marine reptiles of Manitoba
Early mammals (bigger than elephant)
Cadborosaurus of BC
Skeleton of Cady displayed
Ammonite: skeleton up to 10 m
Quebec “fisherman”
Clastic Sedimentary Rocks • Classified according to size of grains large rounded stones : conglomerate large angular stones : breccia (Italian for gravel) sand –size stones : sandstone silt – size stones : siltstone clay-size (not visible) : mudstone & shale
Chemical Sedimentary Rocks • Classified according to chemical substance present : Most common is Limestone, made of calcite (chalk is a variety, made from skeletons of microscopic plants) also, Dolomite, made of the mineral dolomite These rocks are usually made up of skeletons of visible or microscopic animals / plants
2.5 million blocks of foraminifera limestone make up one pyramid - sorry for the car!
Khufu pyramid
Size of blocks
Ca in water • Comes from weathering of minerals and goes into solution as Ca2+ and bicarbonate ions • Because water can’t carry any more in solution, the bicarbonate combines with Ca2+ to form CaCO3 • Many organisms exploit this reaction to form their hard parts • CaCO3 is not soluble, sinks to form sediment • CO2 is removed from the air, thus preventing the planet to get warmer • If limestone (CaCO3) melts to form magma, CO2 erupts from a volcano (recycled)
When the OCEAN EVAPORATES Evaporites: from chemicals precipitating after the sea water evaporates: Halite: common salt Potash: fertilizer (Saskatchewan) gypsum, anhydrite, selenite : fertilizer, “safe food additive”, “mortar” of ancients borax: in soap detergents (TV rock is a B mineral) sodium sulfate: in soap detergents (Sask.)
• Chert, jasper, flint, diatomaceous earth (looks like chalk): made up of quartz which used to be skeletons of microscopic animals (sponges, diatoms) • Diatomaceous earth: insect repellent
Diatoms: the animals with a touch of glass
• Iron Formation: layers of magnetite & chert. Formed before oxygen was part of the air (today, oxygen would attack iron & turn it into iron oxide or rust) • Iron was soluble in water in ancient times and was part of the sea and formed the blood of animals – prob. the sea was also blood color • Rock attracts magnet, frequently red or black
Iron Formation
Watrous lake, Sask.
Salts dissolved in lakes, like the Dead Sea • Remains of ancient sea whose deposits are found under the surface, about 1 km deep • Brought to the surface by movement of groundwater • Watrous (“waters make wonders”, or “doctors” lake) is a spa that has cured the sick for a very long time • The “Royal Inquiry” whitewashed it
Organic remains • Buried with sediment change under pressure • Plant remains become coal, bitumen (asphalt), if plant falls in water where no O2, no breakdown • Coal only forms in tropical swamps • Animal remains become oil & gas (petroleum, diesel) from which we make plastics, lipstick, varnish, etc, etc
Fossil Fuels • are super-concentrated in carbon (+ sulfur, mercury, etc, etc) & big problem when you burn them: their tremendous amount of emissions have changed our climate
Sedimentary structures • Most common : bedding or layering as the sediment or chemical ppt. is accumulating on the ocean floor or on land • Cross bedding: layers in various angles, formed in deserts • Graded bedding: formed in slopes, larger stones at the bottom • Ripple marks: formed by waves • Mud cracks: in dried up areas, clay shrinks into 6-sided blocks • Oolites: look like fish eggs, actually chemical precipitates on the ocean floor by movement of currents
Sedimentary Facies • Environments of deposition • Most sedimentary rocks form in shallow water (continental shelf) with the sediment or chemical transported there by rivers • The bigger the fragments, the closer to the shore at the time: Sand size fragments accumulate close to the shore, clay-size further away from the shore
Mountains form
Metamorphic rocks • “change in form”, alteration of an igneous/sedimentary rock due to a higher T/P environment, usually under a mountain • Alteration in solid form (no melting) • Changes in composition (minerals present) texture (size of crystals) structure (layered or not)
Notice horizontal layers in the rock
The Rockies
Top of Mt. Olympus, Greece
Uzbekistan
“Metamorphic minerals”: only found in metamorphic rocks
• • • • • • • •
Talc Garnet – multi-color Graphite Asbestos Serpentine - green Chlorite - green Epidote – pistachio green Diamond (150 km depth)
• Ruby - red • Lapis lazuli - blue • Jade – green • + most gemstones
Energy supplied by • Higher temperature (from greater depth) • Higher pressure (from greater depth) • Heat from hydrothermal solutions
Result • Denser minerals • More compact rock (no pore spaces) • Rock cleavage (slate for pool tables)
Classification • Foliated (layered) 4 types according to T/P Size of crystals increase 1. Slate (not visible) 2. Phyllite (sheen) 3. Schist (visible) 4. Gneiss Visible & segregated, striped rock
• Non-foliated (massive) Marble : calcite/dolomite Quartzite Serpentinite - green Amphibolite – dark green Soapstone - green Hornfels - green
Gneiss: is used to bake bread it won’t crack, because it has not melted previously
Ancient marble theatre
Metamorphic facies • Minerals are stable under certain T/P conditions • Can tell T & P from the minerals present • Can also tell depth inside the earth where rock formed
12 km deep!
Rock Cycle • • • • •
Continuous recycling of rocks, their minerals, their metals and gases Cycle starts when rocks exposed to the surface Weathering breaks rock down Addition of water forms clays (example: feldspars turn into clays) • Deposition & diagenesis forms sedimentary rocks
• Deeper burial • Water loss as minerals change into other minerals (example: amphibole to pyroxene releasing water) • Rock reorganizes under higher T, P & the presence of hydrothermal fluids and turns into metamorphic rock • With deeper burial there is melting, magma forms and it will either cool in the interior (to form a pluton) or extrude as lava plus gases
Conclusions • One type of rock can turn into a different type • Any type of rock can be exposed to the surface and weathering will break it down. In this way, the rock cycle starts again • The Sun drives the surface processes while the “Heat Within” powers the formation of metamorphic rocks and magma (which leads to the formation of igneous rocks)
All Rocks • IGNEOUS a bunch of minerals no layers only silicates light colors (granite) or dark colors (basalt)
• SEDIMENTARY layered, some maybe thick sediment or chemical mostly limestone in Southern Manitoba
• METAMORPHIC flattened rock layered or massive gneiss most common
Alfred Wegener, early 1900’s
Plate Tectonics • World map available ~ 1,550 AD. He matched coastlines of Africa & S. America • Alfred Wegener travelled the world to prove that continents used to fit together like pieces of a puzzle (Pangea was the supercontinent) • Proposed the continents moved, but he did not know how (Continental Drift discovered around 1974)
Wegener’s evidence • • • • •
Coasts matched Rocks formations matched Fossils matched (examples: dinosaurs, plants) Mountain chains continue across continents Ice Age formations also continue across continents • Present-day coast outlines match exactly if continental shelves are added around continents
New evidence • Paleomagnetism : ancient magnetism preserved in rocks –magnetite crystals line up with magnetic field at the time they form • Earth behaves like a bar magnet. Also, the polarity reverses once in a while • Magnetic reversal pattern of successive lava flows on the ocean floor supports the seafloor spreading theory with identical patterns on both sides of the oceanic ridges
Striped pattern of magnetized rock
Electricity & magnetism go hand in hand • An electric current will form a magnetic field around it • Moving magnet will create electricity • Have you visited a hydroelectric dam recently?
Earth’s Magnetic Field (blue lines)
Magnetism • Evidence from pottery suggests Earth’s magnetic field gets weaker, might disappear in 2000 years or so • Molten iron is a better conductor than copper • If inner core is magnetized, an electric current will be induced in the outer core. That current will generate a magnetic field which will reinforce the original field in the core. Like a self-activating dynamo, the magnetic field will continue to function as long as the planet spins on its axis
Magnetic reversals • 20 in the last 5 m.y. • Last one 730,000 years ago • As basalts cool below their Currie Point (760’C), their magnetization becomes fixed • Reversals were frequent between 170–118 my • Nothing until 83 my • In the last 25 my more frequent • Probably due to changes in the flow of heat between the core & lower mantle
• On the globe : 30 % is Land & 70% is water but 45 % is continents & 55 % is ocean (land + continental shelves)
Lithosphere (plate) : solid made up of crust + upper mantle & in constant, slow motion Asthenosphere : plastic layer underneath the plate, where magma forms
Plate boundaries • Divergent (pull-apart, spreading ridges, rifts): System of inter-connected fissures on ocean floor & Iceland. East African Rift (Dead Sea to Mozambique) Transform (Sliding) : along faults. One side moves in opposite direction to other. Examples: San Andreas Fault, Anatolian Fault
• Convergent (colliding): 3 types • 1. ocean plate against ocean plate: result is subduction with trench forming. Melting produces magma than forms chains of volcanic islands: “island arcs” such as Japan, Philippines, Indonesia, Aleutians, Caribbean. These islands form arcs, because plates meet at oblique angles, not at right angles
Convergent cont. • 2. ocean plate against continental plate. Result is subduction under the continent. Magma forms volcanoes on land. Examples : Nazca collides with S. America and forms the Andes mountains, Cocos plate collides with Central America and forms volcanoes, while Juan de Fuca plate collides with N. America & forms the volcanoes of the Cascadia Mountain range
• 3. two continental plates collide forming mountains. Examples : India collided with Asia to form the Himalayas & Africa collided with Europe to form the Alps & other mountains in southern Europe
Volcanic mounds & Hot Spots • Hot spots are stationary. The plates move over them carrying the volcanic pile with them, much like pulling a carpet & everything on top of it. Example is Hawaiian islands. There is a continuous chain of volcanic mounds on the ocean floor extending to the NW as far as the Aleutian islands- the end of the Pacific plate. The further away from the hot spot, the older the volcanic pile is. In front of the Aleutian islands the oldest mound is 75 m.y. old. That is as old as the Hawaii hot spot.
Driving mechanism • The heat trapped within the earth since its creation provides the energy to drive the plates. • Heat moves upwards towards the surface by convection (compare to heating water in a pot) • Relatively hot areas within the mantle (mantle plumes) have been outlined in the earth’s interior. Eventually, these plumes will create new rifts or hot spots in the crust.
Natural resources & plate tectonics • The intrusion or extrusion of magma in the earth’s crust is responsible for mineral deposits, such as gold, silver, copper, zinc, nickel, etc. Therefore, such deposits are forming at the plate boundaries of today and have been found in former plate boundaries of the earth’s past. • Example: the porphyry copper deposits of the American Cordillera, Central American mountains and the Andes mountains.
Plate Tectonics Theory Explains • Location of volcanoes • Location of earthquakes • Predicts future eruptions & earthquakes • Predicts the discovery of new metal deposits
Video • Iceland: boundary between North American plate and European plate • Continues under the ocean as the mid-Atlantic rift • East African Rift: valley with volcanoes, travertines, hot springs, soda pools – where our oldest ancestors discovered as fossils • Cyprus: copper (name from Cyprus) in old volcanoes • Andes Mountains: porphyry type copper deposits with volcanoes
Shaking & waves • “Earthquakes don’t kill people, buildings do” • In earthquake areas, you have to make sure buildings are built acc. to regulations
Earthquakes (seismic events) • Movements in the crust due to plate tectonics • Energy for shaking the earth comes from stretching of rocks (like an elastic band, it becomes warm when stretched) • Earth behaves like an elastic, can 1. Deform under stress 2. Strained rock stores energy. This energy is released in 2 ways: slowly by continuous movement of the rock (aseismic creep), or suddenly, rocks move past each other along a fault creating an earthquake
Fence displaced
• Most of the energy is used to displace rocks. • Some is released in the form of seismic waves • Accumulated energy is tremendous, equivalent to many atomic bombs • Place of movement is the focus or center with epicenter directly above- where most damage takes place. Deepest focus is 680 km, below that no movement due to high pressure
Seismic waves • P (primary, compressional, pressure) in straight lines, all directions, like sound waves. Possible in solids, liquids & gases. Travel at ~ 5 km/sec • S (secondary, shear) up & down. Only possible in solids. Slower than P • P & S are body waves, travel through whole earth unlike the • L (Love, first to describe them) travel along surface & do most of damage to buildings. Combination of P & S movement
Seismographic stations • Instrument to record movement of ground • A rotating drum anchored to ground with a writing device suspended with a spring so that it is not attached to the ground. • Record of earthquake is the seismogram • Time difference between P & S waves tells us how far the earthquake was (like lightning & thunder)
For your iPhone
Make a seismometer in class!
• Time difference will not tell in which direction the earthquake was • The distance to the earthquake can be plotted as a circle around the recording station • Need to have 3 circles that intersect at 1 point to locate the source of the earthquake. • ~ 100 seismographic stations in Canada
Three circles intersect at one point
Magnitude of an earthquake • The max. up and down movement of the instrument would be proportional to the strength of the quake • Use Richter scale. A logarithmic scale, each number is 10 X bigger than smaller number • A magnitude 5 quake and higher will cause damage to buildings • Highest recorded was 9.5 in Chile, 1960
Effects • • • •
Ground shaking is the most common effect Less damage if building built on bedrock More shaking if built on sediment Worst if built on soil with water. Ground will behave like quicksand (liquefaction) • Surface faulting on the surface will displace a road, fence, etc • Landslides on slopes with unconsolidated material
Effects cont. • Tsunamis if quake below sea floor • Waves of a very long amplitude, hardly noticeable in the ocean, move very fast (1,000 km/h) & become very high approaching the shore and sweep onto land destroying structures & trees on their way (when they hit land they keep moving uphill, this shows how much energy they have)
“Earthquake wedding”: Sichuan, 2008
Sichuan, China: after the quake
Story of tsunamis • 1,650 BC: Minoan civilization (oldest in Europe) destroyed by tsunami on the island of Crete from the Santorini volcanic eruption (the Crees left & prob. moved to N. America : they were the best marines then & now) • Exodus of the Jews from Egypt: water retreats just before tsunami hits -same tsunami ? • 365 AD: Alexandria destroyed by tsunami that killed 50,000 • Last major in 1964 then, nothing until 2004
Satellite picture of Crete & Santorini
Videos/pictures of tsunamis they used to call it “tidal wave” !!
• Very rare • Paintings of Alexandria tsunami & Atlantis tsunami exist • 1 picture of the 1946 tsunami in Hawaii (short video) • 1 short video of a tsunami in Siberia • Fake posters, fake movies to warn people-mostly for the USA people – but did not work! • No major tsunami from 1964 (Crescent City) until 2004!
New wave of tsunamis • They start in 2004 with a Bang! • People tragically caught unaware • Both Indonesians plus thousands of European / American tourists (supposed to be more “educated”) • Only 2 kids, 9 & 10 year old (from England) seem to know what a tsunami is • The 9 year old girl convinced hotel people to move to top floor, all of them saved!
2004 tsunamis • Killed at least 250,000, maybe as high as 350,000 • No one really knows, because whole families/villages were wiped out • Some affected areas were in a state of war with their own country (Indonesia), so they didn’t care to help them!
Sumatra, 2004: lots of video, only 1 picture
Only picture
It is a natural phenomenon
When you feel tremor and you are near the sea • You run uphill • Like all animals (who are smarter ?) including insects & birds . The fish in the sea disappear (they go hiding)
Sumatra, 2004: completely unprepared
Areas affected in yellow
Height of two of the waves
waves have already hit
Destruction
Survivors are hungry and thirsty
Chile, 2010
Japan 2011: lots of video, lots of pictures
The Japanese • Are the only people in the world who are prepared for tsunamis • Tsunami is a Japanese word meaning “harbor wave” • Some towns have built walls along the shore for protection • Have frequent evacuation drills • Even they suffered because of the large waves – final count: 14,000 died
Japanese tsunamis
Cascadia earthquake, 1700 AD with tsunami
First evidence • Came from legends passed by native communities on west coast of Vancouver Island (fiction today is imagination, mythology is real) • One coastal village was wiped out • Canoes were found on top of trees • Was still a legend until new evidence came from geologists discovering a “ghost” forest along the shore
Evidence of Cascadia tsunamis: “ghost forest” along the shore
It is now a fact • West coast of Cascadia is vulnerable to megathrust earthquakes with tsunamis (just like Sumatra is) • Frequency of large tsunamis averages every 300-400 years • People should be prepared for the next one
Juan de Fuca plate in yellow
Cascadia subduction
Fault movement under water creates tsunamis
Effect of earthquake on Vancouver
Sumatra, 2004
Seismic belts • 75% of quakes around the Pacific ocean assoc. with subduction, trenches and volcanoes • 15 % along mountain belts of Europe & south Asia • 5% along the ocean rifts • 5% in other scattered areas
Earthquake prediction • Small periodic tremors usually precede bigger quakes, but sometimes no warnings • Radon gas seeps into groundwater prior to a quake • Unusual animal behavior described previously by ancient authors - Mass migration of ants carrying their eggs - Rats, snakes, weasels, centipedes, worms, beetles migrating out in numbers - Locusts (grasshoppers) creeping through the streets towards the sea - Eels crowded onto the beach in advance of a tsunami - Bees flew from their hives out 2 min before & returned after the shock - Hibernating snakes left their burrows & froze to death rather than return to the earth - Appearance of bats during the day
Video: Earthquakes • India, San Andreas Fault, Mexico, Armenia, Tangshang, Tokyo
Video: Turkey & elsewhere • Specialists in the rescue : remote cameras, listen for noise • Dehydration of victims • Northridge, 1994: 13 seconds, 72 died • Alaska, 1964: 4.5 minutes! “end of the world” • Mexico city, 1985: 22 “miracle babies” • Japan: Earthquake capital of the world
Video: Tsunamis (killer wave) • • • • • • •
Last century: 50,000 died Hilo, Hawaii in 1946 (hit from Alaska) Pacific Tsunami Warning Center from 1948 Hilo hit again in 1960 (from Chile) Frequent disasters in Japan including Okushiri Walls, signs & evacuation drills Crescent City, Calif. In 1964 (from Alaska)
cont. • New danger in Cascadia • It was just a legend • Ghost forest, sand layer from tsunami, land dropped from quake forms salt marsh • People don’t trust tsunami warnings
Video: 5 years after the 2004 tsunami • • • • •
9.3 quake + 6 tsunamis Videos taken by tourists Banda Ache, Indonesia Malaysia : Phuket, Khao Lak, Phi Phi Sri Lanka
Video: Cascadia Tsunamis • Expecting N. America’s biggest disaster (?) • Evidence of past tsunamis • “you can survive a tsunami if you know what to do” • Computer modeling of previous tsunamis help prediction with great accuracy • “people take tsunamis seriously now” • Port Alberni “wave” of 1964
cont. • Movement of mountains in B.C. • Japan records gave exact date & time of the 1700 tsunami • Bottom-sea sampling proved previous tsunamis (from sand layer in the soil) • Research along San Andreas Fault • Buildings reinforced in Vancouver • Seaside, Oregon get prepared with town model
cont. • B.C. hesitated to put warning signs up • Prediction studies done for every town along ocean • Vertical evacuation in strong buildings • Many people still don’t get it (seriously) • 9-yr old girl saved all people in one hotel (2004)
Years between Cascadia tsunamis • • • • • • • •
314 from last one 174 106 269 228 184 173 298
| | | | | | | |
174 136 285 324 211 318 348 732, 754, 350, 462, …
Japan 2011 videos • • • • • •
From You tube Coast Guard boat out at sea Tourist Liner almost capsizes Master boatman saves fishing boat Tsunamis hit Tall buildings swaying from 9.0 earthquake
Earth’s Interior • Information obtained by studying seismic waves, drilling long holes (only a 12 km long in Russia) & studying meteorites which give clues from other parts of the solar system • Seismic waves refract (bend) as they travel in the interior due to higher densities. P waves go right through (~ 20 minutes to cross the earth), while S waves can’t go through outer core (which is liquid)
• Continental crust is 35-100 km thick & • Oceanic crust is only 5 – 8 km thick • The Moho separates the crust from the mantle below • The Gutenberg separates the mantle from the core at a depth of 2,900 km • The center of the earth is 6,400 km away where the temp. is 4,500 ‘C with a pressure of 4 million atmospheres
• Crust is made up of igneous, sedimentary or metamorphic rocks (no meteorites are like that, because the earth’s crust is unique to earth. • The mantle is made up of olivine + pyroxene. The stony meteorites are like the earth’s mantle • The core is made up of iron plus some nickel and cobalt. So, it is like the iron meteorites
You know… • What the planet is made up of • How the earth “works” • The heat within is the power that drives surface phenomena • Earth does not punish people, but people have to learn how to respect nature • People who talk ignorant eventually get hit (example: GW Bush chased by a tornado!)
