Geology 104 - Test 2 Study Guide
Energy is stored in rocks adjacent to the site of a future earthquake as
Elastic strain
Alluvial soils that comprise floodplains are poor soils for agricultural purposes.
FALSE
Because they occur within plate interiors, seismologists can make estimates and short term predictions of the size, location, and recurrence intervals of intraplate earthquakes with incredible certainty.
FALSE
Deep-focus earthquakes are usually the most destructive because the seismic shaking is amplified as the waves approach the surface.
FALSE
Engineers will consider building only on slopes with a factor of safety less than 1.
FALSE
Given their great speed, it is impossible to warn of a tsunami before it strikes land.
FALSE
One of the best ways to prevent landslides is with warning systems.
FALSE
The 2004 Indonesian/Indian Ocean tsunami came as a complete surprise to scientists working in the area.
FALSE
The San Andreas Fault is highly likely to generate tsunamis.
FALSE
The terms "subsidence" and "flow" are used interchangeably to describe a particular type of landslide.
FALSE
Most earthquakes that occur are intraplate earthquakes.
False
Compared to interplate EQ, it is ___ to locate faults at the surface in intraplate areas because ___
Harder, they are typically buried by sediment
The Mercalli Scale is a scale from ________.
I to XII that rates the structural damage due to an earthquake
The 2004 Indian Ocean tsunami originated off the coast of the island of Sumatra, which is part of the country of ________.
Indonesia
The 1700 AD tsunami generated by a large earthquake on the Cascadia subduction zone in the Pacific Northwest was dated most precisely using
Japanese tsunami records
The time intervals between major intraplate EQ is ___ (longer or shorter) than typical intervals between major interplate EQ.
LONGER
________ refers to the tendency for a foundation material to lose its internal cohesion and fail mechanically during earthquake shaking.
Liquefaction
Tsunamis are generated by
NOT: earthquake waves shaking the ocean floor
Oxford, MS would be most likely to feel shaking associated with the next "big one" occurring in the ___ fault zone.
New Madrid
Earthquakes in Hawaii are caused by activity along which type of plate boundary?
None, Associated with Volcanos
The Wasatch Fault is a ___ fault that runs along the western edge of the Wasatch Mountain Range. A great earthquake along this fault could significantly impact the populated area of ___.
Normal, Salt Lake City
A fault is called an ________ fault if it has experienced movement in the last 10,000 years.
Potentially active
There is potential for a great quake along the Cascadia Subduction zone, with possible damage affecting northern California, Oregon, Washington, Vancouver, and Victoria. This zone is an area of thrust faulting, a type of ___ faulting commonly found at a ___ plate boundary.
Reverse, convergent
Large intraplate EQ occurred in the US in the 1800s centered in ___.
SC and MO
Rocks found in the plate interiors tend to be ___ than those near plate boundaries and typically transmit seismic energy greater distances from the epicenter than rocks near plate boundaries.
Stronger, colder, denser, older
Downstream floods typically cover a large area and are produced when long-lasting storms saturate soils and increase runoff into streams and rivers.
TRUE
Earthquakes are the only source of tsunamis.
TRUE
Earthquakes result from the sudden release of elastic strain energy previously stored in rocks surrounding a zone of fault movement.
TRUE
If discharge is held constant, decreasing the size (cross-sectional area) of a river channel would result in an increased flow velocity.
TRUE
It is safer to be on the open ocean than in the harbor when a tsunami arrives.
TRUE
Mudflows typically occur in saturated materials.
TRUE
On earthquake distribution maps, the boundaries of the Earth's tectonic plates are shown as zones of high seismic activity.
TRUE
Some large earthquakes are preceded by smaller magnitude foreshocks.
TRUE
Subsidence of overlying materials may be caused by collapse of "pillars" in a location where the "room and pillar" system of mining has formerly been used.
TRUE
The Cascadia subduction zone in the Pacific Northwest is a location at which tsunamis are generated.
TRUE
The geographic distribution of liquefaction features, such as sand blows, of the same age can be used to estimate the epicenter and magnitude of the prehistoric earthquake that created the features.
TRUE
Tsunamis can cause damage thousands of miles from their source.
TRUE
Which one of the following statements concerning foci and epicenters is correct?
The epicenter is at the surface directly above the focus where the earthquake initiates.
In the United States, earthquakes occurring west of the Rocky Mountains are interplate earthquakes.
True
Intraplate earthquakes occur
Within plate interiors
________ is the maximum possible damage designation on the Modified Mercalli scale.
XII
Caves form in rocks when slightly ________ groundwater dissolves certain soluble rocks.
acidic
An ________ fan is a fan-shaped deposit that forms when a stream flows from a steep mountain channel onto a flat plain.
alluvial
The ________ is directly related to the Richter earthquake-magnitude rating.
amplitude of the recorded seismic waves
p-waves
are fastest
A lahar is a mudflow created when loose volcanic ________ becomes saturated with water. Lahars can be very damaging and are a serious secondary effect of volcanic activity.
ash
The region drained by a single river or river system is called a drainage ________, or watershed.
basin
A ________ channel pattern tends to be wide and shallow, with numerous gravel bars, and may occur in areas with steeper slopes.
braided
A ________ forms where a river flows into the ocean or another larger water body.
channel
Paracutin in central Mexico is an example of a ________ ________, or a small volcano that can form relatively quickly from primarily explosive activity.
cinder cone
Andesite, which forms from magmas with intermediate silica content, is a rock commonly created by ________ volcanoes.
composite
Mt. St. Helens is an example of a ________ volcano.
composite
The cone shape of ________ volcanoes is a result of the combination of lava flows and explosive activity that forms them.
composite
________ volcanoes are also known as stratovolcanoes.
composite
________ volcanoes are the type of volcano responsible for the most death and destruction.
composite
The time of year can impact slope stability, since the depth to the water ________ changes seasonally.
content
The "Ring of Fire" occurs along subduction zones, which are associated with ________ plate boundaries.
convergent
Very slow, gradual displacement along a fault that is not accompanied by felt earthquakes is called tectonic ________.
creep
Slumps (aka rotational slides) differ from translational slides in that soil or rock slides down a ________ slip plane.
curved
Once a large tsunami is generated, it is least noticeable in (deep or shallow) ________ water.
deep
One of the best ways to decrease landslide potential on a slope is to control ________.
drainage
The catastrophic 2004 tsunami was generated by a(n)
earthquake
Moving magma and volcanic fluids may trigger ________, which are often the earliest warning of impending volcanic eruptions.
earthquakes
________ in Thailand are at least one type of animal that appear to have sensed the impending 2004 tsunami.
elephants
The ________ is the point on the surface directly above the site of initial earthquake rupture.
epicenter
The primary human adjustment to volcanic activity is ________.
evacuation
A fracture or fracture system along which rocks have been displaced is called a ________.
fault
In upper parts of drainage basins, intense rainfall over a relatively small area may cause a ________ flood, which can be quite severe locally.
flash
________ is the natural process of overbank flow.
flooding
The flat surface adjacent to a river channel is called a ________.
floodplain
The term viscosity may be defined as a substance's resistance to ________.
flow
Lava with a low silica content and, therefore, a low viscosity, will more likely behave in which of the following ways?
flow down the sides of a volcano
The ________ is the site of initial rupturing associated with an earthquake.
focus
Old Faithful is a ________ located at Yellowstone National Park that periodically shoots steam and hot water into the air at Earth's surface.
geyser
A river's slope, also called its ________, is the vertical drop in elevation over a horizontal distance that it flows.
gradient
Japan, Mexico, the Phillipines, and Indonesia have many active volcanoes and are countries with a ________ (high or low) population density.
high
In some volcanic areas, groundwater is heated when it comes in contact with hot rock, and it may discharge at the surface as a ________ ________.
hot spring
How did the population of Heimaey, Iceland reduce damage from advancing lava flows of Mt. Helgafell toward their island?
hydraulic cooling
In what region did a major tsunami strike in late 2004?
indian ocean
Volcanic debris flows and mudflows are commonly referred to as ________.
lahars
The 1998 tsunami in Papua New Guinea was generated by a submarine ________.
landslide
The shaking associated with a large earthquake in the New Madrid Fault zone would be felt over a much ___ (larger or smaller) area than the shaking caused by a similar magnitude earthquake occurring in California.
larger
An explosion of gas and ash from the side of a volcano is called a ________ blast.
lateral
Magma that reaches Earth's surface through volcanic activity is called ________.
lava
Caves and sinkholes commonly form in ________, which is a sedimentary rock composed of the mineral calcite.
limestone
Pahoehoe is faster moving than aa, because it has a ________ (lower or higher) viscosity.
lower
A common name for molten rock is ________.
magma
A ________ river channel has many bends that migrate back and forth across the floodplain.
meandering
Tsunamis can be detected on the path through the open ocean by
measurement of changes in pressure exerted on the sea bottom by the water column
Overpumping of groundwater in an area may be referred to as "groundwater ________."
mining
The ________ magnitude scale is a measure of the energy released by an earthquake. It does not directly measure the extent of building damage.
moment
A strike-slip fault involves horizontal displacement and is described as either left-lateral or right-lateral. A dip-slip fault involves vertical displacement and is either a reverse fault or a ________ fault.
normal
Why was building damage so extensive in the 1985 Mexico City quake?
not built on solid ground
Which of the following is not a way that humans have been known to induce earthquakes?
oversized trampolines in backyards
An abandoned meandering river channel that has filled with water is called an ________ lake.
oxbow
________ have the highest velocities.
p-waves
The "Ring of Fire" is an area with many volcanoes that surrounds the ________ Ocean.
pacific
Which of the following has the lowest viscosity?
pepsi
The inside of a meander loop where sediment is deposited is called a ________ bar, and the outside of a bend where erosion occurs is called the cutbank
point
Ash flows, also called nuee ardentes or ________ flows, are large volumes of incredibly hot, very fast-moving material that can incinterate everything in their path.
pyroclastic
The common rock type produced by volcanic domes, from viscous magma with relatively high silica content, is called _________.
rhyolite
Which of the following foundation materials is most stable during earthquake shaking?
rock
The ratio of resisting forces to driving forces acting on a slope is referred to as its factor of ________.
safety
The instrument used to record earthquake vibrations is called a ________.
seismograph
An earthquake scientist is called a ________.
seismologist
Basalt is the type of rock that forms from the low silica, low viscosity lava emitted from ________ volcanoes.
shield
The Hawaiian Islands are examples of ________ volcanoes.
shield
Which type of volcano is most associated with subduction zones?
shield
A ________ is a circular area of subsidence into a subterranean void.
sinkhole
A ________ plane is a geologic surface of weakness (such as fractures, weak layers, bedding, or foliation planes) along which slope failure may occur.
slip
The long-term rate of movement along a fault is known as its ________ rate.
slip-rate
S waves travel through _____ and P waves can travel through _____ and _____.
solids; liquids, solids
The height of the water in a river at a particular time is called the ________.
stage
Mining of salt and coal, excessive groundwater pumping, and natural groundwater action have been known to cause to land ________.
subsidence
The ________ is a direct measure of the distance from a seismic receiving station to the focus of a distant earthquake.
time interval between the first P and S- wave arrivals
A tsunami warning system includes seismometers, surface buoys equipped with a bottom sensor (known as a ________), and communication systems.
tsunameter
A seismic sea wave induced by an earthquake is called a _________.
tsunami
Lava and pyroclastic debris erupt at Earth's surface through circular conduits or elongated fissures called volcanic ________
vents
Similar to the way your pancake syrup will be "more runny" when you warm it in the microwave, the ________ of magma is lower when temperatures are higher.
viscosity
The giant tsunami that struck Indonesia in 1883 was caused by a(n)
volcanic eruption
While there may be an increase in resisting forces as roots hold material in place, vegetation may also contribute to driving forces due by adding additional ________ to the slope.
weight
Volcanic hazards in the U.S. exist primarily along the ________ coast.
west
Which is not considered a possible localized cause of intraplate earthquakes?
Changes in tides
Seismic gaps are ________.
Areas along active fault zones or within regions that are likely to produce large earthquakes but have not caused on recently; unusually quiet zones along known active faults
Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5?
3000
The earthquake risk in Alaska is due to a tectonic setting most similar to which of these?
Cascadia subduction zone
