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