types of stress:

-Compression: pressure from both sides

-Tension: pressure from pulling apart

-Shear: opposite pressure, land grinding past other land.

-Strength of the crust: the strength of the continental crust (quartz and feldspar) increases with depth then weakens.

-Brittle (surface/less depth, temp, and pressure): stress makes rock fracture, but rock remains intact

-Ductile (more depth, temp, and pressure): stress makes rock flow in solid state, rock resists deformation.

-Joint: the crack where the rock was pulled apart

-Stresses that form joint:

-Burial and tectonic forces: force from every side of the rock, straight cracks

-Cooling and contraction: ex-when mud dries it cracks

-Unloading: pressure in an uplift, mountain

-Fault:rocks have slipped passed one another

-Movement on fault:

-Normal fault: pressure pulling apart, left side moves up, right side moves down

-Reverse fault or thrust fault: pressure pushing in, left moves down, right moves up

-Strike-slip fault: two sides move horizontally relative to one another.

-Left lateral: block on opposite side moves to the left

-Right lateral: block on opposite side moves to the right

-Folds: layers can be folded

-Anticline: peak of fold (dome)

-Syncline: bottom peak of fold (basin)

-Earthquake: movements within the Earth’s crust cause stress to build up at point of weakness and rocks to deform. Seismic waves radiate from the earthquake’s epicenter.

-Elastic rebound theory: an explanation of how energy is released during an earthquake. As plates move in opposite directions, the rocks on opposing sides of the fault line a subjected to shear stress. They deform until they fracture and they return to almost their original shape except shifted slightly. The distance of the slight shift is called the slip.

-Types of earthquake waves:

-Body waves:

-Primary Wave (P-wave): compresses the material in the direction the wave moves; fastest wave. Moves front and back.

-Secondary Wave (S-wave): shears material side to side, perpendicular to the direction the wave moves. Up and down.

-Surface waves:

-Vertical Surface wave (Rayleigh wave): compresses material up and down in elliptical motion. Circles.

-Horizontal Surface wave (Love waves): shears material side to side.

-Earthquakes are detected using seismometers that record seismic waves.

-To locate the epicenter of an earthquake, you measure the distance between the first p-wave and the first s-wave

-To determine magnitude of an earthquake, you find the amplitude of the biggest wave on the seismogram and see where it is on the richter scale.

-Eastern Hemisphere earthquakes:

-Africa-Europe convergence

-East African Rift

-Mid-Ocean ridges

-India collision

-Subduction of oceanic plates

-Australia collision

-Western Hemisphere earthquakes:

-Alaska subduction

-San Andreas fault

-Central America subduction

-Mid-ocean ridges

-South America Subduction

-India collision

-Mid-Atlantic ridge

-Caribbean subduction

-Earthquake damage

-Tsunami and other flooding

-Landslide

-Rupture

-Structural damage

-Liquefaction

-Fire

-Earth composition

-Upper layer is crust: continental and oceanic

-Mantle: thickest layer

-Core: deepest layer, iron and nickel (molten outer core, solid inner core)

-Lithosphere: Crust (continental + oceanic) + uppermost mantle. Uppermost 100 km of the mantle that is stronger and more rigid than the asthenosphere (lower, hot and weak).

-Isostasy: relationship between crustal thickness and elevation. Thick blocks higher than thin blocks. Denser materials are lower.

-Continental Drift: first suggested by glaciologist Alfred Wegener, 1915.

-Shapes fit together

-Fossils of the same land creatures found on different continents

-Glacial features indicate glaciers coming from directions that are now oceans

-Earth’s magnetism: caused by convection currents in the liquid outer core of the Earth. Normal: North is up. Reversed: South is up. Lava flows record Earth’s magnetic field.

-Sea floor spreading:

-High elevation of ridges: more magma comes up through the ridges then cools at that height making the ridges taller. Thin lithosphere.

-Magnetic stripping: as magma comes out the normal magnetic stripes move away from the ridge and also create new stripes. The stripes are recorded in the floor over time.

-Gradually increasing age of basalt of ocean floor and overlying sediments from the ridge to continental margin.

-Three types of plate boundary:

-Divergent (spreading, move apart)- earthquakes, mild volcanism

-Convergent (subduction, move toward each other)- earthquakes, explosive volcanism

-Transform (strike-slip, move horizontally past one another) -earthquakes, no volcanism

FIRST DIAGRAM

-Closing of an ocean-continental collision: subduction of oceanic part of plate, subduction bring continents closer, continents then collide (wide deformation, thick crust-high elevation)

-Formation of linear islands: ex. - Hawaii

-Plate moves over hotspot

-Volcano forms over the hot spot

-The volcano then becomes inactive as that area of the plate moves away from the hot spot, leaving behind an island.

-The plate subsides as it cools, so islands become seamounts; underwater mountains.

-Oceanic plateaus:

-Rising mantle plume at hot spot

-Submarine flood basalts pour onto seafloor

-Plateau forms over several million years.

Chapter 6 Igneous phenomena - volcanoes and intrusions:

-Factors causing melting in mantle:

-Decompression melting: when two plates move apart, they create a space that can be filled by hot rock that rises buoyantly from below. As this hot rock rises, the pressure on it decreases and the rock can melt.

-Hydrous melting: water being added to aid melting.

-Melting at different kinds of plate boundaries:

-Partial melting: occurs when only a portion of a solid is melted, different minerals might have different melting points.

-Melting in continental rifts: crust pulls apart, solid asthenosphere rises to fill the gap and melts.

-Melting in continental collision: burial and heating of subducted crustal rocks, melting during subduction

-Magma rising: partial melting of source, accumulates into rising magma body, forms magma chambers (solidifies or rises), eruption as lava or ash.

-Lava properties:

-High viscosity: lower temp, and abundant silica chains, lava piles up.

-Low viscosity: higher temp, fewer silica chains, lava spreads out.

-Types of volcanic edifice:

-Scoria cone: tall, hole at top

-Shield volcano: tall, flatter than scoria, magma fed by fissures

-Composite Volcano: tall, fat source of magma

-Volcanic dome: looks like a bulge

-Flood basalts: fissures in the ground release magma, flat-Volcanic eruption products:

-Gas

-Ash: large pillars

-Lava: viscous

-Pyroclastic flows: ash flowing down volcano

-Lahars: mudflows

-Volcanic Explosivity Index (VEI): measure size of plume, and age.

-Scale: 0-8, Hawaiian > Strombolian > Volcanian > Plinial

-Montserrat = VEI 3

-Mt. Pelee = VEI 4

-Krakatau = VEI 6

-Santorini = VEI 7

-Yellowstone Caldera = VEI 8

-Atlantis: says it was sunk by earthquake

-Mosaic legend: river turned to blood, hail and fire, three days of darkness, cloud by day and pillar of fire by night, collapse of the Red Sea. (earthquake? tsunami?)

-Igneous intrusions:

-Dike: newer layer cuts across other layers

-Sill: newer layer cuts across but stays under newest layers

-Batholith: very large igneous intrusion extending deep in Earth crust