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.

Water

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 ________.

focus

On a typical seismogram, ________ will show the highest amplitudes.

surface waves

Large circular downwarped structures are called ________.

basins

A ________ volcano is a very large, gently sloping mound composed mainly of basaltic lava flows.

shield

Major earthquakes are often followed by somewhat smaller events known as ________.

aftershocks

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 ________.

isostasy

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.

orogenesis

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) ________.

seismograph

The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.

elastic rebound

Overall, this type of seismic wave is the most destructive.

surface wave

Which of the following is NOT considered pyroclastic debris?

pahoehoe

________ magma is the most abundant type erupted on Earth.

Basaltic

________ have the highest velocities.

Primary waves

The position on Earth's surface directly above the earthquake source is called the ________.

epicenter

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.

Richter

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) ________.

dome

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 ________.

seismic waves

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.

XII

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.

divergent

The ________ is an example of an active, continent-continent collision.

northward movement of India into Eurasia