ch4 & ch5 - geol

Which of the following earthquake predictions is least reliable?

An amateur geophysicist has warned residents of San Diego to evacuate their homes before an earthquake hits the city later this week.

Why are earthquakes hazards so high in South Carolina?

An ancient, buried fault is located there.

Why is the USGS Did You Feel It? program so important?

It allows for the quick collection and dissemination of useful data concerning shaking during earthquakes.

Without a detailed working theory on the behavior of faults, it appears that we may never be able to determine

a method of short-term earthquake prediction

A fault is

a place where Earth ruptures and two sides move past each other in earthquake-generating events

Which plate boundary has the lowest earthquake frequency due to the warmer rocks at the boundary compared to the other types of boundaries?

divergent boundaries

Paleoseismology

The study of ancient rock and sediment deposits for signs of earthquakes

Neotectonics

The study of the tectonic activity in recent geologic time

Where do shallow earthquakes occur in subduction zones?

in the upper portion of the down-going plate in the overriding plate at the bend in the subduction plate

Based on your interpretation of the shake map, what is a likely reason the city of Newhall experienced more shaking than Burbank?

There is more soft sediment underlying Newhall.

Ignoring California and Alaska, the 10 largest earthquakes in the United States occurred in ____ different states

10

1. Quasi-periodic2 . Clustered 3. Random ___ movements occur in succession for several years and then do not occur again for decades or centuries ___ major movements occur at approximately the same time intervals ___ no definable pattern and inherently unpredictable

2 1 3

In 1984, a group of scientists using an army of instruments predicted an earthquake for the Parkfield, California, area would take place by 1993. An earthquake actually occurred in

2004, 16 years late

Rank the following states in order of earthquake occurrence from 1974 to 2003, placing the state with the greatest frequency of earthquakes at the top and the state with the lowest frequency of earthquakes at the bottom.

Alaska California Hawaii Nevada Washington

An event started in California that is now used in many states and countries to help prepare residents for potential earthquakes. It is called the

Great Shakeout

The first Great Shakeout Event was held in ______ to help prepare residents for the next large earthquake.

California

Rank the type of tectonic plate edge by the magnitude (strength) of the largest earthquakes that occur along it. (Place the boundary that experiences the greatest magnitude earthquakes at the top.

Convergent, transform, divergent

Which two effects on ground surface do dams have that can trigger earthquakes?

Dams cause the earth beneath them to sink isostatically, increasing pressure. Water seeping underneath the impounded reservoir creates a region of high pressure that may cause fault movement.

The USGS has developed a program called ______ that encourages people to report shaking experiences to better measure Mercalli intensity of earthquakes.

Did You Feel It?

The concept of earthquake weather is flawed because, unlike weather patterns, earthquake energy is derived from

Earth's internal energy

True or false: Earthquake early warning systems can predict when an earthquake will occur with great accuracy.

False

Which of the following is true about the tectonic interaction between India and Asia?

It is a collision zone between two continental plates but was a subduction zone in the past when India's oceanic crust subducted below Asia.

Which of the following states has the lowest predicted earthquake hazard(s)?

Minnesota

Earthquake early warning systems work on the principle that

P waves travel faster than S waves and surface waves but do little damage

Which of the following statements accurately describes the movement of a normal fault?

Tensional forces pull one rock mass away and down from another.

Why does short-term earthquake prediction currently appear impossible?

The detailed behavior of fault movements appears to be too unpredictable.

Why is there a depth-related distribution in the power of earthquakes at a subduction zone?

The forces that cause earthquakes align differently with depth, and the rock's resistance to stress changes with depth.

The accompanying ShakeMap shows the relative susceptibility various ground surfaces have to shaking by earthquakes. Red indicates the greatest amount of potential shaking, and blue indicates the least. Based upon this map, what can you infer about the geologic materials that the city of Newhall is built upon?

The materials are likely unconsolidated, such as sand or silt.

Why do subduction zones result in earthquakes with the greatest magnitudes?

The process of subducting a tectonic slab or pushing two continents together requires incredible amounts of energy.

True or false: Every single U.S. state has experienced earthquakes.

True

True or false: Pumping liquids underground has been known to trigger earthquakes.

True

The accompanying image shows the cross-section of a lake that has been disturbed by prior seismic activity. Based upon this cross-section, which of the following statements must be true?

Two earthquakes have occurred since sedimentation began in the lake. Earthquakes occur, on average, every 250 years. The lake is bounded by a thrust fault.

Within the United States the largest earthquakes to occur outside of California and Alaska took place in two different states:

Washington and Hawaii

In which of these scenarios will the plate subduct?

an older, colder oceanic plate that collides with a younger, warmer oceanic plate a warmer, younger oceanic plate that collides with an older continental plate

Big earthquakes do not happen every year in the United States, but their cumulative financial effects are forecast using

annualized earthquake losses

In the United States, $6.1 ________ in annualized earthquake losses (the future potential cost of earthquake damage) are projected.

billion

Numerous earthquakes occurred at Lake Mead in 1935 because

construction of a dam created downwarping of the land surface

The tremendous amount of energy involved in thrusting two tectonic plates together results in________ boundaries having the largest magnitude earthquakes.

convergent

Earth's largest (strongest) earthquakes occur at

convergent boundaries

Tectonic plates slide past one another at transform faults, collide due to ______ motions, and move away from each other due to _____ motions

convergent, divergent

Within a normal fault, one rock mass moves ______ another.

down and away from

The best way to avoid falling objects dislodged during an earthquake is to

duck under a table

California accounts for over half of the predicted annualized ______ losses

earthquake

Humans can trigger __________ through activities such as underground explosions and forcing pressurized fluids underground.

earthquakes

Earthquake weather refers to the belief that

earthquakes occur under certain weather conditions

Which of the following are ways that human activities can trigger earthquakes?

extracting large volumes of groundwater setting off underground explosions adding or removing material at construction sites pumping pressurized fluids underground

The locations where ruptures in Earth's crust occur as two sides move past each other in earthquake-generating events are called

faults

To extract the maximum amount of oil and natural gas from underground, a process called _______ is utilized in which high-pressure liquid is pumped underground to crack open rocks.

fracking

While there is no question that the process nicknamed ________ has increased fossil-fuel energy production in the United States, many environmental concerns remain, not to mention its potential for causing earthquakes.

fracking

Which of the following characterize continental collision zones?

great earthquakes thick crust gigantic seismic zones

The petroleum industry has known for some time that human activity can produce earthquakes, particularly when

liquids are pumped underground at high pressures

Our ability to forecast earthquakes on a(n) ____-term timescale is fairly good, but we have no ability to predict earthquakes on ____-term timescales.

long, short

The seismic-gap method of forecasting earthquakes involves

looking for segments along a fault that have not moved in a long time as compared to other segments

Scientists utilize the sedimentary rock record to estimate the magnitude of ancient earthquakes by

measuring the amount of offset between layers of sedimentary rock

The combined techniques of __________ and paleoseismology can be used to reconstruct the prehistoric earthquake record. (Enter only one word per blank.)

neotectonics

Earthquakes as large as magnitude 5 have been produced in Nevada as a result of the underground testing of _____ weapons

nuclear

The most common earthquake hazard that people encounter is(are)

objects falling on one's head

Thrust faults

occur when one rock mass is pushed above another in a reverse fault movement tend to be inclined at a shallow angle

Annualized earthquake losses are calculated from a number of factors, including

population size shaking potential building types

Fault-movement timing groups fall into one of three classifications: ______ movements, ______ movements, and ______ movements.

random quasi-periodic clustered

The earthquake forecasting strategy that involves plotting the distribution of earthquakes along a fault to identify the locations at which earthquakes may be overdue is called the

seismic gap

Subduction-zone earthquakes are

sometimes extremely powerful

Which of the following are transform plate boundary faults?

the San Andreas fault in California the Alpine fault of New Zealand the Enriquillo-Plantain Garden fault in Haiti

One of the major reasons that short-term earthquake prediction, such as the Parkfield Earthquake Experiment, has been a failure is the realization that

there is no reason the fault-rupture process must occur with regularity

Human-induced earthquakes can be triggered by

underground pumping of fluids nuclear explosions dam construction