Chapter 12-15

Approximately what percentage of Earth's surface is exposed above sea level?

29%

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

5; 30

Four Earth's continental shields

African, Canadian, Australian, and Brazilian

Since the core's mass is about one third of Earth's entire mass, the volume of the core is also of one third of the Earth's entire volume.

False

The density of material below the Moho is less than that above it.

False

The moment magnitude scale is based on energy released and is less accurate than Richter's scale which is based on the amplitude of seismic waves

False

The oceanic crust is less dense than the continental crust.

False

The principle of buoyancy and balance, when applied to Earth's crust, helps us to explain fluctuations in Earth's outer crust, a properly known as

Isostatic adjustment

Which of the following is true of the asthenosphere?

It contains pockets of increased heat, it flows, and it carries the lithospheric plates

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

Which of the following statements about Earth's core is not true?

The inner core is believed to be liquid and the outer core 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

A hypsographic curve is a graph that shows the Earth's surface by area and elevation in relation to sea level

True

A residual "synclinal ridge" may form within a trough of a fold

True

A slope is stable is its strength exceeds the weathering and erosion process

True

Depth of earthquake focus increases with increasing distance from ocean trench

True

Earth was once in a molten state, during which materials became sorted based on density.

True

Ocean floor subducts under continents because the ocean floor is denser than continental material

True

Orogeny means mountain generating

True

The Hawaiian Islands were formed as a result of a rising plume of magma from the mantle

True

The Moho mirrors the surface topography, i.e., high places on the surface of the Earth overlies areas in which the Moho descends to greater depths, and vice versa.

True

The age of the sea floor increases with increasing distance from a mid-ocean ridge

True

The fluid outer core generates 90% of Earth's magnetic field.

True

The magnetic stripes found around mid-Atlantic ridge were due to the magnetic reversal

True

The mean sea level is at 0m

True

Uniformitarianism assumes that the same physical processes we see today are a key to understand the processes that have been operating throughout the geologic time.

True

The dynamic equilibrium model refers to

a balancing act between tectonic uplift and rates of denudation by weathering and erosion in a given landscape

Movement at the geomorphic threshold signals

a conversion of potential energy to kinetic energy

The two types of time

absolute and relative

After a threshold is crossed, the landscape

adjusts to a new equilibrium condition

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

Four evidences Wegener used to prove his hypothesis

coastal lines, rock types, mountain types, and ancient climates

Convergent plates boundaries are characteristics of

collision zones between plates

In 1912, German geophysicist and meteorologist, Alfred Wegener first proposed the ______ hypothesis about the Earth's land mass migration.

continental drift

Four volcanic activity zones

continental rift valley, oceanic-continental plate, sea-floor spreading, and hot spots

A _____, or heartland region, is an old and stable part of the continental crust.

craton

Which of the following gives the correct sequence of layers in the Earth, from the surface to the center?

crust, asthenosphere, lower mantle, core

All processes that cause reduction and rearrangement of landforms are included in the term of

denudation

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

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

faulting

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

focus, or hypocenter

The form that a landscape exhibits results from a balance between

forces acting on the landscape, endogenic and exogenic processes, inputs and outputs of matter and energy

On which part of a slope would rocks tend to fall at the highest speed

free face

Compared to oceanic crust, continental crust is

generally more complex on content and structure

_____ threshold is the point at which there is enough energy to overcome resistance against movements

geomorphic

The science that specifically studies the origin, evolution, form, and spatial distribution of landforms is

geomorphology

Which of the following plays a role in the shaping of Earth's surface?

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

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

half-life

Chemical weathering is greatest under conditions of

higher mean annual rainfall and temperature

The youngest epoch in the geologic time scale is

holocene

In which climates would rock be weathered to the greatest depth?

hot and wet

Volcanic activity located away from plate boundaries is associated with

hot spots

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

hydrologic cycle

The geologic cycle is composed of three subsystems:______, ______, and ______.

hydrologic, rock, tectonic

Three basic rock types

igneous, sedimentary, metamorphic

Knowledge of Earth's interior is derived from

indirect evidence involving the analysis of seismic waves

The Earth's dominant materials are ____ and ____.

iron and silica

Earth's magnetic field

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

In most areas, the upper surface of bedrock is partially weathered to broken-up rock called

regolith

Vertical elevation differences in a local landscape are referred to as

relief

Two types of scale to rate earthquakes _____ and _____.

richter scale; movement magnitude scale

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

rifting

Divergent plate boundaries are characteristics of

sea-flooring spreading centers

An instrument used to record vibrations in the crust is the

seismograph

Which of the following is incorrectly matched?

shearing-stretching

A continental _____ is a region with a craton 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 San Andreas system in California is an example of a

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

When geologists or archaeologists 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 Earth's continental crust.

tectonic activity; weathering and erosion

Heat energy and new materials are brought to the surface from the interior by the

tectonic cycle

Rocks are subjected to stress due to _____

tectonic forces, gravity, and pressure from overlaying rocks

Normal faults are associated with

tension forces

Three types of stress

tension, compression, shear

The rate at which rocks weather depends on

the climate of an area, the type of rock, the amount of vegetation

The most detailed order of relief applies to _____ order relief features.

third

Three types of plate boundaries

transform, divergent, convergent

Which of the following is an endogenic process?

volcanism

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

volcanoes

Other than the rock itself, the most important chemical substance needed for the majority of weathering processes is

water

The disintegration and dissolving of surface and subsurface rock is called

weathering

Which of the following is an exogenic process?

weathering

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

western coasts

Radioactivity dating only can be used to measure relative time

False

Physical weathering dominates in warm and wet climates

False

Which of the following is true of joints?

joints enable more water to move through the ground, joints enhance the rate of weathering

Which layer of planet forms 80% of Earth's total volume, and has an average density of 4.5 g/cm^3?

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

Three types of orogenesis

oceanic-oceanic collision, ocean-continental collision, continental-continental collision

In reality, a landscape behaves as a(an) _____ system

open

Two most abundant chemical elements in Earth's crust

oxygen and silicon

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

pangea

When rock is broken and disintegrated without dissolving, the process in operation is

physical weathering

The asthenosphere can be described as

plastic-like

Uplift of the landscapes creates _____ energy which is converted to _____ energy when materials begin to move downslope

potential; kinetic

Which of the following is incorrectly matched?

radioactive decay heat-exogenic energy source