Chapter 5 - HW (Earthquakes Throughout the United States and Canada)

__________ are the down-dropped areas in the middle of spreading-center domes that are being pulled apart.

rift valleys

A triple junction is the point where __________.

three tectonic plates touch

Which of the following correctly states the order in which a continental area is transformed into an ocean basin as a spreading center forms?

Centering, doming, rifting, and finally spreading

The seismic-gap method of earthquake forecasting works by identifying __________.

segments along a fault that not moved for the longest amount of time

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.

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

The ongoing collision between Asia and the subcontinent of India is resulting in __________.

great earthquakes over a gigantic area

Which of the following sections along the San Andreas fault remained as a seismic gap as of late 2015?

The Crystal Springs area south of San Francisco

How does a locked zone in a fault typically catch up with a creeping section?

By infrequent but large fault movements

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

Others:

-Along the San Andreas Fault in California with its famous earthquakes

The spreading-center segment at the southern end of California's Salton Sea is marked by all but which of the following?

a lack of small earthquakes because magma is too close to Earth's surface

Recent work has shown that the last major earthquake in the Cascadia subduction zone occurred about 9 p.m. on 26 January 1700 and was about magnitude 9. This is known by __________________.

analysis of annual growth rings in trees of downed forests along the Oregon-Washington-British Columbia coast showing no rings after 1699 and Tsunami of 2-m (7-ft) height that hit Japan from midnight to dawn pointing to a 9 p.m. earthquake along the Washington-Oregon coast on 26 January 1700.

In 1985, because of the Michoacan earthquake many buildings collapsed and killed about 8,000 people in Mexico City, even though the city lies 350 miles from the epicenter. All but which of the following caused this?

Collapse of thousands of single-story frame houses

In the 1989 Loma Prieta quake, the Marina District building collapses were extensive, and numerous destructive fires broke out, due to all but which one of the following?

Widespread looting and arson

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

infrequent and large

The best time for an earthquake to occur to minimize loss of life is __________.

during the night when most people are home and asleep

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

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

All of these choices are correct.

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

On 9 January 1857, the San Andreas fault segment between Cholame and San Bernardino broke loose at its northwestern end, and the rupture propagated southeastward in the great __________ earthquake with a magnitude of about 7.9.

fort tejon

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

its northern and western

In 55 years, from 1962-2017, the more than 156,000 in Iran earthquakes mostly from a result of __________.

poor construction

According to figure 4.40, the _________ has the greatest probability for one or more 6.7 magnitude earthquakes between 2003 and 2032.

hayward fault

Spreading ridges produce the largest number of great earthquakes.

false

The compressional movements at subduction zones and continent-continent collisions generate the largest tectonic earthquakes and they affect the widest areas.

true

The North Anatolian fault in Turkey is a 1,400-km-long fault zone made of numerous subparallel faults that split and combine, bend and straighten, and there is reason to expect major earthquakes to occur progressively farther to the west, ever closer to Istanbul.

true

The Dead Sea fault zone is an Eastern Hemisphere analogue of the San Andreas Fault in California.

true

The primary cause of deaths in earthquakes in modern times is people being swallowed alive by the ground, rather than by building collapse.

false

The biggest disasters occur when great earthquakes occur at great depths.

false

The deadliest earthquake in history occurred in 1556 when about 830,000 Chinese were killed in and near Xi'an on the banks of the mighty Huang River.

true

Most of the subduction-zone earthquakes of today occur around the rim of the Pacific Ocean or the northeastern Indian Ocean.

true

The greatest earthquakes in the world occur _____________.

where plates collide with each other

Resonance can increase the duration buildings shake during an earthquake.

true

In the areas of most rapid subduction, the down-going slab may remain rigid enough to spawn large earthquakes to depths of 700 km.

false

At depths below 100 km, subduction zone earthquakes occur almost exclusively in the interior of the colder oceanic lithosphere, the heart of the subducting slab.

true

Earthquakes at subduction zones result from different types of fault movements, depending on whether they occur in shallow versus deeper realms.

true

The duration of strong ground shaking in the 1964 Alaskan Good Friday earthquake was 70 minutes.

false

The 1985 Mexico City earthquake was caused by eastward subduction of a small plate, the Cocos Plate, beneath the North American Plate.

true

The biggest earthquake ever recorded instrumentally occurred on 22 May 1960 in southern Chile with a seismic moment magnitude of 9.5.

true

The Cascadia subduction zone is 1,100 kilometers long, and its characteristics of youthful oceanic plate and strong coupling with the overriding plate are similar to situations in southwestern Japan and southern Chile where very large earthquakes have occurred.

true

Recent work has shown that the last major earthquake in the Cascadia subduction zone occurred about 9 PM on 26 January 1700 and was about magnitude 9.

true

Major southern California faults, such as the Imperial, San Jacinto system, Cerro Prieto, Elsinore, and Laguna Salada, also appear to be part of the San Andreas Plate boundary fault system carrying peninsular California to the northwest.

true

Shallow subduction zone earthquakes occur __________________.

All of these are correct.

The fires from the 1906 San Francisco earthquake did about ten times as much damage as the earthquake itself.

true

The San Francisco section of the San Andreas Fault has had an excessive number of earthquakes relative to other parts of the San Andreas Fault.

false

The San Andreas Fault has different behaviors along its length.

true

The creeping movements along some segments of the San Andreas Fault are shown by millimeters per year of offset of sidewalks, fences, buildings, and other features.

true

Common reasons for building failure in the World Series quake included poor connections of houses to their foundations, buildings made of unreinforced masonry or brick-facade construction, and two- to five-story buildings deficient in shear-bearing internal walls and supports.

true

In the San Francisco Bay area, during the nineteenth century, earthquakes with magnitudes greater than 6 were much less common than in the 20th century.

false

Most of the 131 fatalities from the Good Friday earthquake in Alaska in 1964 were due to fire caused by rupturing of gas lines.

false

A series of 5 moderate earthquakes moved northward up to the Calaveras Fault preceded both the large quakes of 1865 and 1868.

true

Iceland is built on a mature spreading center that has been opening for the last 100 million years.

false

The Dead Sea and the Sea of Galilee __________________.

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

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

Continental plate versus mantle plate

Which of the following is not a divergent margin?

Aleutian Island Arc

Which of the following does not have a significant convergent margin?

African Plate

Most earthquakes are explainable using __________.

plate-tectonics theory