Ch 12-13 exam review

approximately what percentage of earths surface is exposed above sea level?

29%

the oceanic crust thickness is about _____ km, and the average continental crust thickness is ____ km.

5; 30

list 4 volcanic activity zones:

Continental rift valley, Oceanic-Continental plate convergent, Oceanic-oceanic plate convergent, Sea-floor spreading

list 2 types of scale to rate earthquakes ______ and ______

Richters scale and moment magnitude scale

which of the following is not an example of an age-relationship based on absolute dating?

The Coconino formation in the Grand Canyon is older than the Kaibab formation

uniformitarianism assumes that the same physical processes we see today are a key to understanding the processes that have been operating throughout the geologic time. t/f

True

there are two types of time, which are ________ and ________.

absolute, relative

at which of the following locations does subduction occur?

along collision zones between continental and oceanic plates

folded layers of rock can form a wavelike pattern of troughs and crests. the layers near the crest form

an anticline

which of the following is an example of a first order of relief?

an ocean basin

a _______, or heartland region, is an old and stable part of the continental crust.

carton

list 4 evidences Wegener used to prove his hypothesis ________, _________, ________, and ________.

coastal lines, fossils, rock types/mountain belt, ancient climates

convergent plates boundaries are characteristics of

collision zones between plates

in 1912, German geophysicist and meteorologist, Alfers Wegner first proposed the _______ hypothesis about the earths land mass migration.

continental drift

which of the following gives the correct sequence of layers in the earth, from the surface to the center?

crust, asthenosphere, lower mantle, core

list 3 types of plate boundaries

divergent, convergent, transform

which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?

eon, era, period, epoch

the area at the surface directly above the subsurface location where seismic waves are initiated is termed the

epicenter

since the cores mass is about one third of earths entire mass, the volume of the core is also of one third of earths entire volume. t/f

false

the density of material below the Moho is less than that above it. T/F

false

the moment magnitude scale is based on energy released and is less accurate than Richters scale which is based on the amplitude of seismic waves. t/f

false

the oceanic crust is less dense than the continental crust. t/f

false

when rock strata are strained beyond their ability to remain an intact unit, displacement, occurs in a process known as

faulting

radioactivity dating only can be used to measure relative time. t/f

flase

the motion of seismic waves is initiated in a subsurface area along the fault plane called the

focus, or hypocenter

compared to oceanic crust, continental crust is

generally more complex on content and structure

which of the following plays a role in the shaping of earths surface?

gravity, the action of wind, water, and ice. the radioactive decay of atoms

the decay rate is expressed as _______, the time required for one half of the instable atoms in a sample to decay into "daughter" isotopes.

half-life

the youngest epoch in the geologic time scale is ______________

holocene

volcanic activity located away from plate boundaries is associated with

hot spots

the geologic cycle is composed of three subsystems:

hydrological, rock, tectonic cycle

three basic rock types are _______ (fire-formed, molten), _______ (from settling out), and ________ (transformed from any other rock through extreme heat or pressure).

igneous; sedimentary; metamorphic;

Knowledge of Earth's interior is derived from

indirect evidence involving the analysis of seismic waves

earths magnetic field

is variable, and it has phased to zero some nine times during the past 4 million years

Vertical elevation differences in a local landscape are referred to as

relief

several large, linear lakes are formed in East Africa. this is evidence of what process?

rifting

divergent plate boundaries are characteristics of

sea-floor spreading centers

an instrument used to record vibrations in the crust is the

seismographer

list three types of stress

shear, compression, tension

which of the following is incorrectly matched? a) strain-stress-induced b)compression-shortening or folding c)tension-stretching or faulting

shearing-stretching

a continental ______ is a region with a carton is exposed at the surface.

shield

if you were paranoid of earthquakes, which of the following area would be the safest to live?

shield

the earths dominant materials are ______ and ______.

silicon and iron

the San Andreas system in California is an example of a

strike-slip fault, transform fault, right-lateral motions

when geologists or archeologists dig downward into a unit of rock or sediment, they are digging "back in time". this fact is based on the principle of ___________.

superposition

the combination effects of ________ (powered by internal energy) and ________ (powered by the sun through motion of air, water and ice) create earths continental curst.

tectonic activity, weathering and erosion,

? heat energy and new materials are brought to the surface form the interior by the

tectonic cycle

? the transportation and deposition of materials y media powered by solar energy is the

tectonic cycle

Rocks are subjected to stress due to

tectonic forces, gravity, pressure from overlaying rocks

Ch 13

tectonics, earthquakes and volcanism

normal faults are associated with

tension forces

which of the following statements about earths core is NOT true? a) its composed primarily of iron c) temp in the core reaches several thousand degrees d) temps and pressures are higher in the inner core that outer core.

the inner core is believed to be liquid and the outer core is solid.

which of the following is true of the earthquake in the Liaoning Province of NE China on February 4, 1975

the quake was successfully forecasted and 3 million people were evacuated.

the most detailed order of relief applies to ______ order relief features

third

a hypsographic curve is a graph that shows the earths surface by area and elevation in relation to the sea level. t/f

true

a residual "synclinal ridge" may form within a trough of a fold. t/f

true

depth of earthquake focus increases with increasing distance from ocean trench t/f

true

earth was once in a molten state, during which materials became sorted based on density. t/f

true

ocean floor subducts under continents bc the ocean floor is denser than continental material. T/F

true

orogeny means mountain generating. t/f

true

the Hawaiian Islands were formed as a result of a rising plume of magma from the mantle. T/F

true

the Moho mirrors the surface topography, i.e., high places on the surface of the earths overlies areas in which the Moho descends to greater depths, and vise versa. T/F

true

the age of the sea floor increases with increasing distance from a mid-ocean ridge. t/f

true

the fluid outer core generates 90% of earths magnetic field. T/F

true

the magnetic stripes found around mid-Atlantic ridge were due to the magnetic reversal. t/f

true

the mean sea level is at 0m. t/f

true

which of the following is an endogenetic process?

volcanism

which of the following are located along the mid-ocean ridge?

volcanoes

which of the following is an exogenic process?

weathering

the most active tectonic regions of North and South America are on the

western coasts

list 4 earths continental shields

Canada, Brazil, African, Australian

the principle of buoyancy and balance, when applied to earths curst, helps us to explain fluctuations in earths outer crust, a property known as

isostatic adjustment

which of the following is true of the asthenosphere?

it contains pockets of increased heat. it flows. it carries the lithospheric plates/.

which layer of the planet forms 80% of earths total volume, and has an average density of 4.5g/cm3

mantle

which of the following gives the correct sequence of layers in the mantle, from bottom to top?

mantle; upper mantle; asthenosphere

people often say that California is going to "fall into the ocean." this idea is totally wrong because the San Andreas fault would have to be a ______ fault associated with _______ forces for this to happen.

normal; tension

list 3 types if orogenesis:

oceanic plate-continental plate, oceanic plate-oceanic plate, continental plate-continental plate

two most abundant chemical elements in earths curst are _______ and _______.

oxygen and silicon

Wegener used _____ to name a supercontinent approximately 225 million years ago.

pangea

the asthenosphere can be describes as

plastic-like

which of the following is incorrectly matched? a) endogenic-internal processes b)exogenic-external processes d) weathering-exogenic breaking and dissolving the crust

radioactive decay heat-exogenic energy source