UPCAT SCI WAVES

Geology

Study of Earth's structure, history, and processes

Geosphere

Solid Earth layer (crust, mantle, core)

Crust

Outermost Earth layer; up to 100km below sea level

Continental Crust (Sial)

Portion of crust not covered by ocean

Oceanic Crust (Sima)

Portion of crust under the ocean

Lithosphere

Crust + upper solid mantle; rigid

Asthenosphere

Semi-solid layer below lithosphere; upper mantle; rocks begin to melt

Mantle

Layer below crust; extends to 2900km; mostly molten rocks

Outer Core

Liquid iron and nickel

Inner Core

Solid iron and nickel

Tectonic Plates

Rigid pieces of crust and upper mantle

Plate Tectonics

Theory describing large-scale motions of the lithosphere

Continental Drift Theory

Earth once had a single continent (Pangaea) surrounded by Panthalassa

Sea-floor Spreading

Ocean floor extends when two plates move apart

Divergent Boundary

Plates move apart; constructive; forms ridges

Convergent Boundary

Plates move toward each other; destructive; crust is destroyed

Convergent: Oceanic-Continental

Forms trenches

Convergent: Oceanic-Oceanic

Forms trenches

Convergent: Continental-Continental

Forms mountain ranges and volcanoes

Transform Boundary

Plates slide past each other; conservative; crust neither created nor destroyed

Focus/Hypocenter

Point underground where earthquake originates

Epicenter

Point on surface directly above the focus

P Waves

Primary; compressional; fastest; travels through all mediums; particles move in direction of wave

S Waves

Secondary; shear; slower than P waves; solids only; particles move perpendicular to wave

Rayleigh Waves

Surface wave; ground roll; rolling up-and-down motion; weakens with distance

Love Waves

Surface wave; horizontal sideways motion; occurs in layered ground

Richter Scale

Measures magnitude (energy released); consistent regardless of location

Mercalli Scale

Measures intensity (felt effects); varies by location; based on human observation