Chapter 9: Earthquakes and Volcanoes

The average elevation of Earth's total surface is

-2070 m

The wave amplitude associated with a magnitude 8 quake on the Richter scale is how many times more greater than that of a magnitude 6 quake

100

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

29 percent

On avg how often would you expect an earthquake of between moment magnitude 5.0-5.9 and Mercali V-Vll to occur

800 times a year

the basin and range province in the western US is a result of_____faulting produced by_____forces

normal;tensional

on avg, how often would you expect an earthquake of greater than a richter8.0 and Mercalli XII to occur;

only once every few years

which of the following can lead to the formation of mountains

plate collisoins and volcanic activity, exposure of plutons by erosion of surrounding landscape, faulting. (all of the above)

Vertical elevation differences in a local landscape are referred to as

relief

Compressional stress along a fault can result in a dropped footwall block relative to the hanging-wall side, producing a

reverse fault

the presence of horst and grabens indicates the occurrence of

rift activity

the north anatolian fault in turkey, and the san andrew fault in cali are

right-lateral, strike slip, transform faults

an instrument used to record vibrations in the crust is the

seismograph

which of the following is incorrectly matched

sheasring and stretching or faulting

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

shield

because of the processes responsible for the formation of the himalayan mts, the crust in this region of the world has been

shortened and folded

the san andrew system in cali is an example of a

strike-slilp fault, transform fault, right-lateral motion, (all of these are correct)

which of the following represents a surface whose relief is opposite that expected based on the fold patter in the rocks of which it is composed

synclinal ridge

The average elevation of exposed land is

875m (2780 ft)

tensional stress along a fault can result in a dropped hanging-wall block relative to the footwall side, producing a

normal fault

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

seismic gaps invetigations involve

paleoseismology and the history of activity along specific plate boundaries

The eventual catastrophic eruption of mt saint helens was

related to seafloor subduction at the west coast of North America

The variety of surface features on the earth results from

tectonic activity, gravity and weathering and erosion (all of these)

normal faults are associated with

tensional forces

pulverized rock and clastic materials ejected violently during an eruption are called

tephra, or pyroclastics

Which of the following is toe used to rate an earthquake on the moment magnitude scale

the amount of death and destruction that occured

the greatest loss of human life (250,000) this century resulted from which earthquake event

Tangshan, China, 1976

the major impact of earthquake prediction on a region would be

a decline in business activity and damage to the local economy

orogenesis refers to

a general term for the beginning of a mountain-building episode that thickens continental crust

A hypsographic curve is

a generalized curve showing the earth's surface by elevation in relation to sea level.

small ares of high strain along a fault are termed

asperities

The phrase "considerabe-to-serious damage to buildings" would be used in the

Mercalli

the appalachians formed as a result of the

alleghany orogeny

which of the following is true regarding the moment magnitude scale a scale which quantifies the amount of energy released by an earthquake.

an 8.0 on the scale is equal to 31.5 times more energy release than a 7.0

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

an anticline

Which of the following is an example of a first order of releif?

an ocean basin

Division among topographic regions are based on

arbitrary criteria regarding height or descriptive criteria that are in common use.

volcanos formed from silica-rich magma

are highly explosive and dangerous

lava plateaus, such as columbia river plateau, are formed from____magma, which has a______viscosity.

basaltic;low

which of the following is not he result of extrusive volcanic activity

batholith

a brittle rock is likely to respond to stress by______, whereas a ductile rock is likely to respond by ______.

breaking;bending

Molten rock that pours forth of Earth's surface is called

magma

explosive eruption tend to build up

composite volcanos

the nucleus of old crystalline rock in each of the principal continental masses is called a

continental shield, or craton

when a 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 location along the fault plane called the

focus

compared to oceanic crust, continental crust is

generally more complex in content and structure

Volcanic activity located away from plate boundaries is associated with

hot spots

concerning mt saint helens which of the following is not correct

it is an example of shield volcano in form

warping produces bends in rocks that are ________those produced by folding.

larger than

which of the following statements about shield volcanos is ture

the form from mafic magma

which of the following is not produced by normal faulting

the himalayas

fault types are defined by

the relative motion of the hanging wall and foot wall

which of the following is an example of a third order of relief

the sacramento valley

The concept of "orders of relief" refers to

the scale of features

which of the following is incorrect regarding the series of earthquakes in southern cali in 1992

the sequence did not involve the san andrew fault system

which of the following is true regarding harmonic tremors

they are produced by sub-surface movement of magma beneath a volcano

Which of the following is not true of terranes

they are very similar to composition to the continents to which they attach

which of the following is incorrect relative to the principle locations of volcanic activity

they occur around the perimeter of the atlantic ocean basin

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

third

the grand tetons best represent a

tilted fault block

Terranes refer to

displaced and migrating pieces of earth's crust

high mountains consisting of tightly folded and overthrust sedimentary rock layers. as well as metamorphic rocks, are formed

during plate collisions

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

epicenter

a topographic region is characterized by local relief of less than 100m is considered

a plain

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

a syncline

the greatest amount of crustal shortening would be associated with

a thrust fault

a cinder cone is formed form relatively________viscosity magma with a ________gas content

low;high

effusive eruption are not related to which of the following

magma with 50-75 percent silica, high in aluminum

which of the following is a cause of wrapping

mantle convection, hot spots, isostatic adjustment (all of these)

a scale used to classify and describe the effects of earthquakes on terrain, construction, and local damage conditions is the

modified Mercalli scale

foreshocks may be caused by

the breaking of some asperities before the main movement occurs, small movements that occur when some rocks break in limited areas of a fault plane prior to the main movement, a limited number of lapilli breaking prior to the main movement, the breaking of asperities and small movements prior to the main movement only (all of these)

The undulating form that gives Earth's surface its character and general configuration is called

topography

composite cones have steep slopes and experience_____eruptions because they are composed of ______magma.

violent;felsic

the most active tectonic regions of north and south america are the

western coasts