Geology Final: Practice Questions

If Alaska and California are ignored, the list of 10 largest U.S. earthquakes shows ____________.

10 events affecting at least 10 different states

Typically how many magnitude 4.0 earthquakes occur as magnitude 5.0 earthquakes?

10 times

The oldest rocks on the ocean floor are approximately how old?

200 million

Earth is about __________ years old.

4.5 billion

Using paleoseismic data, how often do very large earthquakes (Mw>7) occur in the New Madrid Seismic Zone?

500 years

Paleoseismologic analysis of trenches cut across faults and folds in the New Madrid, Missouri, area has led the U.S. Geological Survey to forecast a 25% chance of a magnitude __________ earthquake here within the next 50 years.

6 to 7

A magnitude 5.0 earthquake releases _______ times as much energy as a magnitude 3.0 earthquake

900

Which of the following states has the lowest earthquake risk?

Florida

Seismic waves that travel only near Earth's surface are of two main types: _________ waves.

Love and Rayleigh

Which of the following phases passes through the outer core?

PKP

All of the continents were once combined into a single supercontinent called ____________.

Pangaea

The ________ waves advance in a backward-rotating, elliptical motion.

Rayleigh

__________ waves travel only through solids; on reaching liquid or gas, the wave energy is reflected back into rock or is converted to another form.

S

Which state listed below is most likely to have a magnitude 9 or larger earthquake in the next several hundred years?

Washington

Three basic classes of collisions include all but which of the following?

continental plate versus mantle plate

After lava cools below the __________ point atoms in iron-bearing minerals become magnetized in the direction of Earth's magnetic field at that time and place.

curie (550C)

The __________ is measured in cross-sectional view as the angle of inclination from horizontal of a tilted rock layer, and _______ is viewed in map view as the compass bearing of the rock layer where it intersects a horizontal plane.

dip; strike

A normal fault occurs when the hanging wall moves ________ relative to the footwall.

down

When a number of earthquakes along in the same general area over the course of a few months or years, the event is referred to as a(n) __________ .

earthquake cluster

In order to construct an earthquake hazard map which of the following do you NOT need?

earthquake depths

Prehistoric earthquakes may be interpreted using faulted pond sediments. The amount of offset of sediment layers from one earthquake is proportional to the ________________.

earthquake magnitude

The point on Earth's surface directly above the point where the fault first ruptures is called the what?

epicenter

The modified Mercali Intensity Scale is used to measure the __________ of an earthquake.

epicenter and magnitude

Moving progressively away from the ridges, the ocean water depths increase systematically with seafloor age due to all but which of the following?

erosion of the older ocean floor by deep ocean currents

Which of the Following States has the lowest seismic hazard?

florida

The Moon is thought to have formed __________.

from material that coalesced after an impact between Earth and a Mars-sized object

Which of the following is considered a primary earthquake hazard?

ground shaking

What causes the up-and-down wiggles on a seismogram?

ground vibrations

An isotope's half-life is equal to the time it takes __________.

half of the parent atoms to decay into daughter atoms

The Great Basin region between the eastern Sierra Nevada in California and the Wasatch Mountains in Utah ______________________ in response to plate-tectonic forces.

has expanded in an east-west direction

What is the name of the surface manifestation of a mantle plume?

hot spot

Which of the following can be used to measure plate motions?

hot spot track

Which of the following is not an example of a process which can trigger earthquakes

hydraulic fracking

A rock subjected to higher temperatures would be expected to behave __________.

in a more ductile manner

Constraining bends in large strike-slip faults commonly "lock up"; thus, movements there tend to be __________.

infrequent and large

The Pacific Plate subducts along _________ edges and creates enormous earthquakes, such as the 1923 Tokyo seism.

its northern and western

What kind of fault would generate the smallest fault scarp?

left lateral strike slip fault

In San Francisco's Marina district in 1989, some fill underwent permanent deformation and settling, and some formed slurries as underground water and loose sediment flowed like a fluid in a process known as __________.

liquefaction

What is the primary process driving tectonic plates?

mantle convection

Marine magnetic anomaly belts are most narrow when and where?

mid ocean ridge's and when the magnetic field switches

When compared to California, seismic energy in the eastern U.S. is transmitted __________.

more effectively in the older, more solid rocks

Another class of active faults is created by southern California pushing into the "Big Bend" of the San Andreas Fault; these faults are __________.

mostly east-west-oriented thrust faults (reverse faults)

Earthquakes in Hawaii are mostly related to ________________.

movement of volcanic magma beneath the ground

The dominant type of faulting in the Great Basin region is ______________.

normal faulting

Faults on which the dominant forces are extensional are recognized by the separation of the pulled-apart rock layers in a zone of omission; these are __________.

normal faults

Which of the following states has the highest earthquake risk?

Arkansas

Which seismic phase is a "depth phase"?

pP

The PGA in a seismic hazard map stands for what?

peak ground acceleration

The time between each cycle of a wave is called what?

period

Most earthquakes are explainable using __________.

plate tectonic theory

The hot-spot-melting-through-lithosphere process forms lines of extinct volcanoes on the ocean floor, from youngest to oldest, __________.

pointing in the direction of plate movement

As radioactive atoms decay, heat energy is _________.

released

________ faults are commonly found at areas of plate convergence where subduction or continental collision occurs.

reverse

With compressional forces, the hanging wall moves upward relative to the footwall; this type of fault is referred to as a __________ fault.

reverse (and thrust)

Which of the following statements best describes the current state of earthquake prediction?

scientists cannot yet accurately predict most earthquakes

Which of the following accurately describes the state of the continents and ocean 65 million years ago?

seafloor spreading had opened and connected the North and South Atlantic Ocean but North America and Eurasia were still partial connected.

Which of the following describes a record of ground motion with respect to time?

seismogram

The amount of relative motion of one block over a fault surface relative to another block is called the fault what?

slip

When magma is on the move at shallow depths it commonly generates a swarm of __________.

small earthquakes referred to as harmonic tremors

Aftershocks are __________ in magnitude and occur __________ the main shock?

smaller; after

The __________ segment of the San Andreas fault is the only one not to have a long rupture in historic time. In prehistory, it has ruptured every 250 years on average, but the last big movement was in 1690.

southern

In the earthquake cycle what quantity(s) increase prior to an earthquake?

stress

Horizontal offsets in streams occur at what kind of fault?

strike-slip

When most of the movement along a fault is horizontal, the fault is referred to as a __________ fault.

strike-slip

Which kind of earthquake producing fault would NOT produce a tsunami?

strike-slip

What type of plate boundary has deep earthquakes?

subduction zones

Earthquakes are most commonly caused by what?

sudden earth movements along faults

What are the slowest seismic waves?

surface waves

What part of the earth generates the Earth's magnetic field?

the core, the inner core which is predominately made up of iron

The uppermost layer of the Earth's Lithosphere is called what?

the crust

The surface projection of an earthquake is called the what?

the epicenter

The farther away a seismic station is from an earthquake's hypocenter the __________.

the longer the delay is between the arrival of the P waves and S waves

Using the seismic gap method, scientists identify section "C" of a fault as a seismic gap. Which of the following possible answers correctly states what this means?

the next major earthquake will likely occur in section "C" but it is not a guarantee.

The frequency of a wave is _____________.

the number of waves passing a given point per unit time

The largest earthquakes along western North America are due to subduction beneath the continent. They include __________.

the plates subducting beneath Oregon and Washington which generated a magnitude 9 earthquake on 26 January 1700

If sea floor spreading occurs at a constant rate, the widths of magnetized seafloor strips have__________ ratios as the lengths of time between successive reversals of Earth's magnetic field.

the same

Which of the following is not a basic tenet of plate tectonics?

the slab pulled into the asthenosphere begins the process of melting and moves into the liquid core

A triple junction is the point where __________.

three tectonic plates touch

The large left step in the San Andreas Fault in the Los Angeles area causes compressive ruptures along east-west-oriented ________ faults as in the 1971 San Fernando and 1994 Northridge events.

thrust

Liquefaction occurs when seismic waves cause __________.

water to be injected into sediment causing the grains to lose cohesion and behave like a fluid

The slide-past motions of long transform faults occur in all but which of the following?

where the Indian subcontinent touches Asia

Can the same fault be classified as both a strike-slip and a transform fault?

yes

Which of the following is an example of ductile deformation?

anticline

What is the best way to identify an active plate boundary?

any earthquakes

The Dead Sea and the Sea of Galilee __________________.

are pull-apart basins and the result of strike-slip motion

Which of the following concepts best explains why a mass of low-density material in the mantle rises?

buoyancy

Organic material in sediment layers is dated by measuring the amount of radioactive ________ present.

carbon

What is responsible for the bend in the Emperor-Hawaii seamount chain?

change in direction of plate motions

The seismic moment is calculated by multiplying all but which of the following quantities together?

The Modified Mercalli Intensity at the epicenter

Which statement accurately describes the planets of our solar system?

The four inner planets are smaller and rocky and the four outer planets are giant icy bodies composed mostly of hydrogen and helium.

Which of the following represents evidence for major fault movement on the Seattle Fault zone about 1,100 years ago?

all of these choices are correct

Which property of seismic waves is primarily used for measuring earthquake magnitude?

amplitude