Chapter 4

Which of the following accurately describes the subparallel fault system that includes the San Andreas fault?

It is a 1,200 km (750 mi) long, right-lateral strike-slip fault system.

Why does building on filled-in wetlands increase earthquake-related hazards?

Shaking is amplified, and deformation or liquefaction of the ground supporting the buildings can occur.

What is the cause of the powerful earthquakes and the resulting large tsunamis that occur in the area of Indonesia?

Subduction of an oceanic plate

Which type of tectonic setting listed below has the largest number of strong earthquakes?

Subduction zones

How did the Nazca plate move with respect to the South American plate to cause the largest earthquake ever recorded?

The Nazca plate moved eastward and downward beneath the South American plate, causing ruptures along a long and wide stretch of the subduction zone.

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

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

Why are scientists predicting a large earthquake for the Pacific Northwest of the United States?

The Cascadia subduction zone occurs there and appears to be overdue for a large earthquake.

What is the tectonic setting of Japan?

The Pacific plate is diving under Japan, causing powerful subduction-zone earthquakes there.

Which of the following are transform plate boundary faults? (Select all that apply.) The San Andreas fault in California The Alpine fault of New Zealand The Tokai fault of Japan The Enriquillo-Plantain Garden fault in Haiti

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

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.

What is the reason divergent boundaries have fewer earthquakes than other boundaries? Multiple choice question.

The rocks located there are warmer, which prevents them from building up a lot of stored stress.

What factors contributed to the collapse of Interstate 880 during the World Series (Loma Prieta) earthquake? (Select all that apply.)

The supporting columns failed at joints where the steel bars in them were discontinuous. The supporting columns failed as the soft ground beneath them was deformed by the shaking.

What are the problems posed by the widespread use of concrete floor slabs in Haiti? (Select all that apply.)

They are supported by flimsy concrete columns that fail in earthquakes. They are weak in earthquakes. They are heavy.

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

convergent

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.

Why is Japan subjected to powerful earthquakes?

It is located at a subduction zone.

The earthquake forecasting strategy that involves plotting the distribution of earthquakes along a fault to identify the locations at which earthquakes maybe overdue is called the ______ method.

seismic-gap

Subduction-zone earthquakes are ______.

sometimes extremely powerful

What tectonic action has occurred in western North America over the last 5.5 million years that is responsible for the earthquakes in central and southern California?

The Gulf of California has opened up in a rifting action that has caused land west of the San Andreas fault to attach to the Pacific plate.

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.)

1. convergent 2. transform 3. divergent

Seismic gaps are formed along segments of an active fault that _______.

have not experienced an earthquake in a long time

A large continental collision between Asia and ______ is causing the uplift of the Tibetan Plateau and the continued formation of the Himalayan mountains.

india

What is the Enriquillo-Plantain Garden fault in Haiti?

A left-lateral transform fault (slide-past) related to the boundary between the Caribbean plate and the North American Plate

What is the cause of the earthquake hazard in Pacific Northwest of the United States?

A subduction zone

What caused the large tsunami that struck Indonesia on 26 December 2004?

A long (1,500 km) fault rupture at a convergent plate boundary where a plate is being subducted

Which plate boundary has the lowest earthquake frequency?

Divergent boundaries

Which of the following contributes to the large number of fatalities caused by earthquakes in Haiti?

Heavy horizontal floor slabs and poorly built concrete buildings are common.

What is the danger posed by building parking garages on the first floor of buildings?

They are often built with fewer internal walls, lateral supports, and less bracing, which weakens the support for the floors above.

What is the tectonic setting of Haiti?

Two parallel, east-west trending transform faults pass through Haiti where it sits at the northern edge of the Caribbean plate.

The largest earthquake ever recorded was caused by ______.

a rupture along the Nazca plate as it was converging with the South American plate

Earth's largest (strongest) earthquakes occur at ______.

convergent boundaries

When a number of earthquakes occur in a relatively short amount of time, the sequence of events is called a(n) ______.

eartquake cluster

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

An earthquake cluster is ______.

the occurrence of a number of earthquakes in the same region over a relatively short amount of time

The San Andreas fault in California is a ______ fault.

transform

Why does liquefaction increase the damage caused by earthquakes?

It causes the sediment supporting buildings to behave like a fluid.

In which of these scenarios will the plate subduct? (Select all that apply.) A warmer, younger oceanic plate that collides with an older continental plate A larger continental plate that collides with a smaller continental plate 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 An older, colder oceanic plate that collides with a younger, warmer oceanic plate

Where do shallow earthquakes occur in subduction zones? (Select all that apply.)

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

The soft first story of a building created by building a parking garage often results in the first floor _______ when shaken during an earthquake.

Blank 1: pancaking or collapsing

Short, inactive segments along active faults are called ____ _____.

Blank 1: seismic Blank 2: gaps

The double-decker portion of I-880 that collapsed during the 1994 Loma Prieta earthquake did so because it was built on a ______ foundation and had a _______ flawed design.

Blank 1: weak or soft Blank 2: structural

If two tectonic plates converge and no subduction occurs, which of the following is true?

Both of the plates must be continental crust.

The San Andreas fault is described as "locked" in the area of San Francisco. What does this mean for the fault?

Virtually all the tectonic stress is stored as elastic strain that will only be reduced in a big earthquake when the fault finally breaks.