Quiz 16: Earthquakes

As a dense oceanic plate begins to bend down into a trench, it stresses slightly at the top of the bend and normal faults occur.

P-waves are compressional waves in which the rock vibrates back and forth parallel to the direction of wave propagation.

Earthquakes occur more or less uniformly throughout the Earth in the recent past.

The elastic rebound theory involves the sudden release of progressively stored energy in rocks.

Most earthquakes occur at great depths.

Surface seismic waves originate at the epicenter of an earthquake.

Small earthquakes following the main surface wave arrival are called foreshocks.

The point on the earth's surface immediately above the focus is the seismic center.

The time interval between the first arrival of a P-wave and the first arrival of an S-wave increases with distance from the focus of an earthquake.

Body waves are seismic waves that travel through the Earth's interior.

By studying seismograms of an earthquake on a distant fault, geologists can tell which way rocks moved along that fault.

A seismogram is a recording device that produces a permanent record of earth motion.

Surface waves are the fastest earthquake waves.

The Modified Mercalli Scale determines earthquake intensity, a measure of an earthquake's effect on people and buildings.

S-waves pass through solid rocks and liquids.

An earthquake of Richter magnitude 5 releases 32 times more energy than an earthquake of magnitude 4.

During an earthquake, buildings built on hard rock are damaged more than buildings built on soft sediment.

Earthquakes occur most commonly in the plate boundaries.

Paleoseismology studies the past record of earthquakes.

The most important concentration of earthquakes in the world is the Mediterranean-Himalayan Belt.

A(n) _____ is a trembling or shaking of the ground caused by the sudden release of energy stored in rocks beneath the Earth's surface. A) tsunami B) volcano C) rupture D) rumble E) earthquake

Rupture begins at the _____ and then spreads rapidly along the fault plane. A) epicenter B) point of contact C) plate boundary D) focus E) shear plane

Both P-waves and S-waves can pass through ____. A) brittle zones B) solid rock C) solid rock and liquids D) liquids E) elastic zones

The __, the distance between the epicenter and focus, for earthquakes is about 670 km. A) p-wave B) first arrivals C) travel-time curve D) depth of focus E) Love wave

____ are the waves of energy produced by an earthquake. A) Seismic B) Light C) Tsunami D) Ocean E) Electrical

The paper record of an earthquake is a ____. A) hypocenter B) Mercalli Intensity scale C) travel-time curve D) seismogram E) moment magnitude

_____ maps are useful for assessing how different areas respond to seismic waves and provide valuable information for earthquake planning. A) Focus B) Intensity C) Epicenter D) Magnitude E) Intermediate

____ focus earthquakes are the most common. A) Deep B) Hypocenter C) Intermediate D) Shallow E) All depths are equally represented.

A ____ plots seismic-wave arrival time against distance. A) travel-time curve B) seismogram C) seismometer D) Mercalli Intensity scale E) Richter scale

_____ waves tend to be incredibly destructive to buildings because they produce much ground movement and take a long time to pass. A) Body B) Love C) Rayleigh D) S E) P

The point within the earth where seismic waves first originate is the _____. A) scarp B) epicenter C) focus D) trace E) origin

The ______ is the most famous example of a right lateral transform fault. A) New Madrid Seismic Zone of Arkansas B) San Andreas Fault in California C) East African Rift D) Choctaw Fault of Oklahoma E) Dead Sea Rift

Perhaps 90 percent of the destruction in the 1906 San Francisco earthquake was caused by ____. A) fires B) building collapse C) landslides D) soil displacement E) tsunamis

The greatest loss of life in the 1964 southern Alaska earthquake was from _________. A) landslides B) tsunamis C) fires D) building collapse E) soil displacement

In the elastic rebound theory, earthquakes are caused by the sudden release of progressively stored _____ in rocks. A) seismic waves B) strain C) stress D) tectonism E) ductile behavior

A _____ is the first wave to arrive at a recording station following an earthquake. A) Love wave B) Rayleigh wave C) S-wave D) P-wave E) surface wave

____ are seismic waves that travel through the Earth's interior, spreading out from the focus in all directions. A) X-waves B) R-waves C) Surface waves D) Refracted waves E) Body waves

____ are earthquake waves that cause the most property damage. A) Surface waves B) P-waves C) X-waves D) S-waves E) Body waves

____ -waves are the slowest body waves. A) M B) S C) R D) P E) X

The time interval between the first arrival of P-waves and the first arrival of S-waves ____ with distance from the focus of an earthquake. A) does not change B) cannot be measured C) increases D) varies irregularly E) decreases

Tsunami waves may move faster than ____. A) a speeding bullet B) P-waves C) S-waves D) 800 km/hr E) 2000 mph

On the modified mercalli intensity scale the maximum value is _______. A) XVI B) XV C) XIV D) XIII E) XII

A series of earthquakes that occurred near _____ in 1811-1812 were the most widely felt earthquakes to occur in recorded history. A) New Madrid, Missouri B) Plymouth, Massachusetts C) Charleston, South Carolina D) San Francisco, California E) Attica, New York

Although large earthquakes are rare in the central and eastern United States, when they do occur they tend to be very destructive because _______. A) they occur infrequently B) the crust there is cool and brittle C) more people live in that region D) the faults in that region are older and larger E) the crust in that region is thicker

The effects of ground motion caused by an earthquake do not include _____. A) permanent land surface displacement B) fire C) volcanism D) landslides E) soil liquefaction

A(n) _______ is a seismic sea wave. A) body wave B) S-wave C) R-wave D) tsunami E) tidal wave

First motion studies of mid-ocean ridges show that the faults there are ____, and parallel to the rift valley. A) subduction B) strike-slip motion C) compression D) deep focus earthquakes E) normal

One suggested cause of deep focus earthquakes is ______. A) collapse of minerals into denser forms B) collapse of pore space in sedimentary rocks C) collision of convection currents D) friction between the core and the mantle E) the rise of core material into the mantle

______ would be associated with Benioff zones. A) Andesite volcanoes B) Oceanic trenches C) Edges of continents D) Island arcs E) All the answers are correct.

Deep focus earthquakes occur at a maximum depth of ______. A) 100 km B) 550 km C) 670 km D) the Earth's center E) the core mantle boundary

If the measured amplitude of vibration of a rock is 1 cm for a magnitude 4 earthquake then the rocks will move ______ during a magnitude 5 earthquake. A) 2 cm B) 4 cm C) 8 cm D) 10 cm E) 20 cm

The most important concentration of earthquakes by far is ______. A) the Mediterranean-Himalayan belt B) the San Andreas fault C) the Arctic zone D) the Atlantic basin E) the Circumpacific belt

Richter scale values above 7 are not accurate. The ______ scale is a more objective method of measuring the energy of a large earthquake. A) seismic trace B) moment magnitude C) P-wave amplitude D) Modified Mercalli E) gravity meter

For most of the 20^th century earthquake magnitude was reported on the _______ scale, a scale that has never exceeded a magnitude 8.6. A) moment magnitude B) surface-wave C) Richter D) Gutenberg E) Modified Mercalli

_____ earthquakes probably occur along older faults that are no longer at plate boundaries, for example the New Madrid Missouri earthquakes of 1811-1812. A) Interplate B) Normal C) Intraplate D) Transform E) Subduction

Deep rocks behave as _____ material under stress rather than breaking. A) liquid B) brittle C) ductile D) isotropic E) vacuum

Which of the following is not used to aid in earthquake prediction? A) tsunamis B) foreshocks C) increase of radon emissions from water wells D) patterns of earthquakes E) seismic gaps

_____ is a measure of an earthquake's effect on people and buildings. A) Intensity B) Magnitude C) Amplitude D) Duration E) Longevity

_____ can occur when water-saturated soil turns from a solid to a liquid as a result of an earthquake. A) Creep B) Liquefaction C) Solifluction D) Soil collapse E) Gelatinization

___ stations are the minimum needed to determine the location of an earthquake epicenter. A) Five B) Two C) Three D) Four E) Six