28 terms

Geology Unit 2

4 Principles of Stratigraphy
horizontality, stratigraphic superposition, lateral continuity, cross-cutting relationships
gaps in rock record because
gap in stratigraphic sequence that marks absence in part of rock record
types of uncomformities
angular, noncomformity, disconformity
equating ages of strata that come from two or more different places
Wegners Theory of continental drift
matching continents, climate, fossils and rock formations
Problem with wegners theory
couldn't explain why or how continents moved
2 piece of info recorded by magnetite
which way is north and orientation
divergent margin
boundary along which two plates move apart
two plates come together
subduction zone
subduction zone
lithosphere plate plunges into mantle beneath another plate
hot spot
rising mantle plume of material partially melts lithosphere above it (hawaii)
what drives plate motion?
still active research, but thermal motion of mantle is partially responsible
ability of a liquid to flow
study of earthquakes and seismic waves
seismic waves
elastic shock wave that travels outward in all directions
pressure with direction
point under the surface where EQ begins
point on Earth's surface directly above focus
body wave
travels through earth's interior
surface wave
travels across earth's surface
P-wave or compressional wave
pass through any medium
alternating pulses of compression and expansion
S or shear wave
side to side or up/down forces
not transmitted through liquids
travel slower than P-waves
how to locate earthquakes
3 stations determine distances to epicenter
EQ is where three circles intersect
the greater the interval b/w P and S wave, the farther away the EQ is
Richter Magnitude scale
intensity based on amplitudes of seismic waves on seismograph
logarithmic scale (1-10)
Mercalli Scale
what people feel/see
love waves
fast shaking, side to side
arrive first
Rayleigh Waves
undulating up and down
arrive second