Earth Science Exam #2
The amount of destruction caused by earthquake vibrations is affected by ________.
all of these
– nature of the surface material
– design of structures
– intensity and duration of the vibrations
________ is a major dissolved volatile constituent in both magmas and volcanic gases.
Which one of the following is true regarding tsunamis?
They occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only a few feet.
A transform fault is ________.
a strike-slip fault that forms the boundary between tectonic plates
Which of the following statements best describes the big Hawaiian volcanoes?
are situated in the interior of a large, Pacific plate above a hot spot deep in the mantle
Cinder cones ________.
all of these
– have very steep slopes
– consist largely of pyroclastics
– are usually less than 300 meters (1000 feet) high
In a normal fault ________.
the hanging wall block above an inclined fault plane moves downward relative to the other block
When an earthquake occurs, energy radiates in all directions from its source. The source is also referred to as the ________.
On a typical seismogram, ________ will show the highest amplitudes.
Large circular downwarped structures are called ________.
A ________ volcano is a very large, gently sloping mound composed mainly of basaltic lava flows.
Major earthquakes are often followed by somewhat smaller events known as ________.
Which one of the following statements concerning cinder cones is false?
The cinders and other pyroclastic particles are consolidated into welded tuff.
The concept that rocks of the crust and upper mantle are floating in gravitational balance is known as ________.
Deep ocean trenches are surficial evidence for ________.
sinking of oceanic lithosphere into the mantle at a subduction zone
The ________ in California is the boundary between the North American and Pacific plates.
San Andreas strike-slip fault
________ are usually the most abundant gases emitted during basaltic volcanism.
Water and carbon dioxide
Which of the following factors help determine whether a volcanic eruption will be violent or relatively quiescent?
all of these
– composition of the magma
– amount of dissolved gas in the magma
– temperature of the magma
Which kind of eruptive activity is most likely to be highly explosive?
eruptions of big, continental margin, composite cones or stratovolcanoes
The term ________ refers specifically to geologic mountain building.
Cooler, older, oceanic lithosphere sinks into the mantle at ________.
subduction zones along convergent plate boundaries
Magma tends to rise toward Earth's surface principally because ________.
rocks become less dense when they melt
P waves ________.
are faster than S waves and surface waves
What volcanic events formed Crater Lake, Oregon? When did they take place?
Caldera collapse followed major ash and pyroclastic-flow eruptions 6000 years ago.
A typical rate of seafloor spreading in the Atlantic Ocean is ________.
2 centimeters per year
The record of an earthquake obtained from a seismic instrument is a(n) ________.
The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.
Overall, this type of seismic wave is the most destructive.
Which of the following is NOT considered pyroclastic debris?
________ magma is the most abundant type erupted on Earth.
________ have the highest velocities.
The position on Earth's surface directly above the earthquake source is called the ________.
The ________ earthquake was accompanied by extensive fire damage.
San Francisco, 1906
A syncline is ________.
a fold in which the strata dip toward the axis
In 1980, ________ was the first Cascade Range volcano to erupt since Mt. Lassen in 1915-16.
Mt. St. Helens
The ________ magnitude scale is a measure of the energy released. It does not directly measure the extent of building damage.
The Richter magnitude of an earthquake is determined from the ________.
amplitude of the largest seismic wave
All of the following are evidence supporting the theory of plate tectonics except for ________.
changes in the Moon's orbit due to shifting plates
The elastic rebound theory for the origin of earthquakes was first proposed by ________ following the ________ earthquake.
Reid; 1906, San Francisco
The 1943 eruption of Paricutin in Mexico was characterized by ________.
cinder cone building and basaltic lava
Which one of the following best describes volcanism in the Cascade Range, northwestern United States?
related to plate subduction
The Black Hills of South Dakota are a good example of a(n) ________.
Kilauea and Mauna Loa are ________.
basaltic shield volcanoes
The distance between a seismological recording station and the earthquake source is determined from the ________.
arrival times of P and S waves
Most of the active volcanoes on Earth are located in a belt known as the ________.
Ring of Fire
Most of our knowledge about Earth's interior comes from ________.
Folded limestones that occur high in the Himalayas were originally deposited as sediments in a ________.
marine basin between India and Eurasia
________ is the maximum possible damage designation on the Mercalli scale.
New oceanic crust and lithosphere are formed at ________.
divergent boundaries by submarine eruptions and intrusions of basaltic magma
Which one of the following statements is correct?
S waves travel through solids and P waves travel through liquids.
Which of the following combinations should favor folding rather than faulting?
high temperature and high confining pressure
Which region has the greatest concentration of currently active volcanoes?
the circum-Pacific area
Which statement about the May, 1980, eruption of Mount St. Helens is false?
During the eruptive period, the mountain peak was substantially built up by new lava flows and pyroclastic debris.
Pull-apart rift zones are generally associated with a ________ plate boundary.
The ________ is an example of an active, continent-continent collision.
northward movement of India into Eurasia