Science Rev

Triangulation Method

Triangulation Method

used by seismologists to find the epicenter of an earthquake using 3 recording stations.

Triangulation Method

it is used in short-range earthquakes.

formula for distance

d = time difference x 100km / 8 seconds

Distance-Time Graph

uses the travel time of P and S waves. It is used in wide-range earthquakes.

Convergent Boundary

two plates collide with each other

Divergent Boundary

mid-ocean ridges are formed and fissures are produced

Transform Boundary

two plates slide past each other

Continental-Oceanic

the thinner but denser oceanic plate subducts where it melts and becomes hot molten rocks

Oceanic-Oceanic

both plates or the older oceanic plate will subduct because it is denser

Continental-Continental Features

no subduction

Continental - Oceanic Features

Trench, Mountain Ranges, Volcanic Island Arc

Oceanic-Oceanic Features

Volcanoes, volcanic island arcs, trenches

Continental-Continental Features

Mountain ranges, plateu

Convergent

Nazca - S. American, Philippine-Eurasian, S. American - Antarctic, D

Transform

African-Antarctic, Antarctic-Australian

Divergent

Pacific-Antarctic, Nazca-Pacific, African-S. American

Mantle Convection

warm mantle currents drive and carry plates of lithosphere along like a conveyor belt

Ridge Push

(Buoyant) upwelling mantle at mid ocean ridges----newly formed plates at oceanic ridges are warm and so have a higher elevation at the oceanic ridge than the colder, more dense plate material further away; gravity cause the higher plate at the ridge to push away the lithosphere that lies further from the ridge

Slab Pull

older, colder plates sink at subduction zones, because as they cool, they become more dense than the underlying mantle. The cooler sinking plate pulls the rest of the warmer plate along behind it.

The Earth's interior has tremendous heat very high pressure underneath

because it has no mechanical probes and has not been subjected to any actual exploration

Crust

outermost and thinnest layer

Mantle

middle part ; makes up most of the Earth’s volume and mass

Outer Core

made up of molten liquid/metallic materials

Inner Core

made up of solid nickel and iron. Its temperature reaches up to 5000 Degree C.

Asthenosphere

weakest layer above the mantle where the lithosphere floats

Lithosphere

Crust + Upper Mantle

Seismic Waves

Produced through the rapid release of energy in earthquakes

Seismic Waves

Radiates in all directions from the focus

Surface

• travels within the Earth’s surface

• comes after body waves

Love Waves (A. E. H. Loves) (1911)

• faster than Rayleigh waves

• side to side horizontal motions (snake)

• most damaging in structure

Rayleigh Waves (John William Strutt, Lord Rayleigh)

• rolls along the grounds (side-side;up-down) similar to the wave motion direction

• most of the shaking is felt

Body Waves

• moves through the inner layers of the Earth

• used by scientists to study the layers of Earth

• higher frequency

Primary (P)

• travels quickly through solid, liquid, and gas

• faster than S waves

• Compressional: parallel to the direction of the waves

Secondary (S)

• travels slower in solids

• slower than P waves

• sheer/transverse - forces the ground to sway; PERPENDICULAR to the wave direction

How scientists study the Earth's interior

Speed, Reflection, Refraction

Continental Jigsaw Puzzle

the edge of one continent matches/fit to the edge of other continents

eg. S. America - Africa

Fossil Records

remains/traces of once a living thing that live in the remote past

Glossopteris

found in 250 million years old rocks found in South America

Messosaurus and Lytosaurus

fresh water reptiles found their fossils on S. Africa, Antarctica, Australia, and India

Rocks Formation

rocks formation/layers of the Africa is lined-up with the rock formation/layers of South America as if it's a long mountain range

Coal Deposits

coal beds are formed due to the compaction and deposition of swamp plants located in the Southern Africa, Antarctica, South East Asia, Indian sub-continents and South American.

Seafloor Spreading

proposed by Harry Hess and Robert Dietz (1960)

Seafloor Spreading

hot, less dense materials from below the Earth's crust rises towards the surface at the mid-ocean ridge

Lines of Evidence in Seafloor Spreading

Magnetic Reversal Magnetic materials found on rocks

ELEMENTS FOUND IN THE CORE

Iron Calcium Potassium Magnesium Titanium Sodium Oxygen Silicon Hydrogen Nickel