Earthquakes and volcanoes test 2 - Chapter 4
In which of these scenarios will the plate subduct? (Select all that apply.)
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
The uplift of the Caucasus and Zagros mountain ranges and earthquakes in their vicinity are being caused by the collision between the ______ and Eurasian tectonic plates.
Arabian
Where do most of the subduction-zone earthquakes of today occur?
Around the rim of the Pacific Ocean and in the northeast Indian Ocean
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.
Which of the following accurately summarizes the use of the seismic-gap tectonic forecasting method in Chile?
Historic records, including an event described by Charles Darwin, were used to identify a seismic gap that was then heavily monitored using GPS.
Which of the following are common sources of data used to conduct tectonic and earthquake research?
Historic written records Global positioning systems (GPS)
Where do shallow earthquakes occur in subduction zones? (Select all that apply.)
In the upper portion of the down-going plate At the bend in the subduction plate In the overriding plate
A large continental collision between Asia and ____________ is causing the uplift of the Tibetan Plateau and the continued formation of the Himalayan mountains.
India
Which of the following describes the spreading center basin related to the northern end of the Gulf of California?
It continues from the Gulf of California in Mexico and finally stops at the end of the Salton Sea in the United States.
What is the tectonic setting of the Dead Sea fault zone?
Pull-apart basins are growing in the overlaps of the Dead Sea transform fault zone.
On the western side of the Arabian plate, what is causing the earthquakes?
Slide-past motion with transform faults
Which of the following accurately describe the tectonic boundaries of the Pacific plate? (Select all that apply.)
Slide-past motions dominate in the northeast Pacific and along its eastern border with California. The Pacific Plate subducts along its northern and western edges. Smaller earthquakes occur at its spreading centers.
______ is determined by measuring vertical and horizontal movement along active faults and the length of time needed to accumulate enough stress to trigger a rupture or slip along a fault
Slip rate
A fault is ______.
a place where Earth ruptures and two sides move past each other in earthquake-generating events
The largest earthquake ever recorded was caused by ______.
a rupture along the Nazca plate as it was converging with the South American plate
What is the reason divergent boundaries have fewer earthquakes than other boundaries?
The rocks located there are warmer, which prevents them from building up a lot of stored stress.
How is the Arabian plate related to the powerful earthquakes occurring in Eurasia?
The spreading centers that formed the Arabian plate are pushing it into Eurasia, causing collision uplifts.
What is creating the down-dropped rift valleys in pull-part basins that have formed the Red Sea, Gulf of Aden, and the Great Rift Valley?
The triple junction of three spreading centers
Which side of the Arabian plate has a slide-past motion with its neighboring plate that is causing deadly earthquakes?
The western side
Which of the following accurately describe the earthquake hazards associated with the tectonic collision between India and Asia? (Select all that apply.)
There are large seismic gaps waiting to be filled. Millions of new buildings are at risk since they were built without seismic-safety inspections.
Why is an ocean basin opening up north of the Gulf of California in the Salton Sea area of California?
There is a developing spreading-center segment of the rift that opened the Gulf of California.
How well did the seismic-gap forecasting method work in Chile?
A big earthquake occurred within the identified seismic gap.
Why are powerful earthquakes projected to hit Mexico City in the near future?
A large seismic gap exits along a nearby subduction zone.
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 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
What is a tectonic triple junction?
A point where three plate edges touch
What is the cause of the earthquake hazard in Pacific Northwest of the United States?
A subduction zone
The triple junction in _______________ has created a rift valley with many topographic features including valleys, domed highlands, lakes, and volcanic peaks.
Africa
The 1964 earthquake in Alaska was very powerful (9.2Mw), yet the loss of human life was not as high as it could have been. What factors helped to limit the loss of life? (Select all that apply.)
Alaska is not a very densely inhabited area. The tsunami struck when the tides were low. Above-average temperatures helped to prevent cold-related deaths as heating systems were being repaired.
If two tectonic plates converge and no subduction occurs, which of the following is true?
Both of the plates must be continental crust.
Which of the following human conditions can increase the destruction caused by earthquakes?
Building houses out of mud or brick in earthquake-prone areas Building on top of soft sediment Having a building height that matches the period of the seismic waves so as to produce resonance
Order the stages involved in forming an ocean basin. (Place the first step at the top.)
Centering Doming Rifting Spreading
Match the stage of ocean basin formation to its description. Instructions
Centering - The lithosphere moves over an especially hot region of the mantle. Doming - Mantle heating causes melting, and that results in the surface of the Earth extending upward. Rifting - Gravity pulls an uplifted area apart. Spreading - New seafloor is formed.
The deadliest earthquake ever recorded occurred in 1556 in ________________; most people at the time lived in caves dug into soft sediment that collapsed when it was shaken.
China
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 plate boundary has the lowest earthquake frequency?
Divergent boundaries
Match the direction of relative motion to the correct tectonic-plate boundary.
Divergent zone - Pull-apart Convergence zone - Colliding Transform fault - Slide-past
______ can be used to determine the rate and direction of tectonic motion wherever they are placed along the ground.
Global position systems (GPS)
What has been the effect of the triple junction located in the northeast Africa since its development about 25 million years ago? (Select all that apply.)
It has created the Arabian plate by splitting it from northeast Africa. The influx of seawater into a rift zone has created a sea between Africa and separated the land on the Arabian Plate. It has created steep escarpments and dramatic valleys in northeast Africa.
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.
Which of the following statements accurately characterizes the earthquake activity in the Salton Trough?
It is one of the most earthquake-active areas in the United States.
What does the word slip refer to when used to describe earthquakes?
It means movement has occurred along a fault.
How did the Arabian tectonic plate form?
It was cut off of the African continent by new spreading centers in the Red Sea and Gulf of Aden.
Which of the following accurately describes the tectonic setting in the area of the Red Sea, Gulf of Aden, and the northeastern portion of Africa?
Magma beneath northeastern Africa has caused doming, which resulted in gravity-fueled pull-apart faulting and rifting.
What geologic feature is best associated with continent-continent collision?
Mountain range
What caused the pull-apart basins in the Red Sea fault zone that filled with water to create the Dead Sea and the Sea of Galilee?
Overlaps (steps) in the north--south trending transform (slide-past) fault
Most present-day earthquakes occur around the edge of the ___________ Ocean.
Pacific
Which of the following accurately describes the relationship between buildings and earthquake fatalities?
Poor building design results in a lot of deaths in earthquakes as homes collapse.
Which of the following accurately characterize spreading center earthquakes? (Select all that apply.)
Small and moderate-size earthquakes dominate. Earthquakes can occur in swarms as magma migrates underground.
Which of the following natural conditions can increase the destruction caused by earthquakes? (Select all that apply.)
Soft sediments near the surface Resonance of seismic waves
Match the area of the Pacific plate with the dominant type of plate boundary that occurs there. Instructions
Southern California and Northern Mexico - Transform or slide-past Southeastern Pacific Ocean - Divergent or pull-apart Western and northern Pacific Ocean - Convergent or push-together
Which of the following accurately summarizes the earthquake hazard in Turkey?
Strong earthquakes and poorly constructed buildings built on top of soft sediment combine to make earthquakes in Turkey extremely hazardous.
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
Which of the following are transform plate boundary faults? (Select all that apply.)
The Alpine fault of New Zealand The Enriquillo-Plantain Garden fault in Haiti The San Andreas fault in California
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 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.
What is causing the earthquakes in the region of India, China, and Pakistan?
The India plate's push into Asia
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.
What is the tectonic setting of Japan?
The Pacific plate is diving under Japan, causing powerful subduction-zone earthquakes there.
What factors contributed to the 1556 earthquake in the Shaanxi Province of China being the deadliest earthquake in history? (Select all that apply.)
The earthquake occurred early in the morning, when people were asleep in their poorly constructed homes. Dwellings were built by digging caves into silt and fine sand that had little cohesion.
Why do the common earthquakes of the Salton Trough tend to occur in swarms?
The earthquakes are related to the forceful movement of magma beneath the crust.
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.
Select the statements below that accurately describe the 1964 earthquake event in Alaska. (Select all that apply.)
The ground shook for a long time, causing many mass-wasting events and a large tsunami. The earthquake had a magnitude of 9.2Mw. It occurred on Good Friday, 27 March.
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.
Why are the interiors of subducting slabs the only places on the slab where powerful earthquakes can occur at great depth?
They are the only places left on the descending slabs still cold enough to resist the pressures before breaking in a rigid manner.
What are the problems posed by the widespread use of concrete floor slabs in Haiti? (Select all that apply.)
They are weak in earthquakes. They are supported by flimsy concrete columns that fail in earthquakes. They are heavy.
How did tree rings prove useful in determining the timing and occurrence of a large earthquake in the Pacific Northwest in winter of 1700?
They indicated the ground was dropped to a lower elevation, causing an influx of seawater that killed the trees.
Which of the following characterize continental collision zones? (Select all that apply.)
Thick crust Gigantic seismic zones Great earthquakes
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 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.
The emergence of the spreading centers in the Red Sea and the Gulf of Aden has caused the formation of the Arabian Plate by cutting it off from ______.
africa
Foreshocks are defined _____ the mainshock occurs.
after
Foreshocks can only be labeled as such ______.
after a larger earthquake (mainshock) succeeds them
Small earthquakes too weak to knock over buildings or cause fatalities are most likely located at ______.
spreading centers
Most of the fatalities in earthquakes are caused by ______.
buildings and homes collapsing
The tremendous amount of energy involved in thrusting two tectonic plates together results in ______________ boundaries having the largest magnitude earthquakes.
convergent
Tectonic plates collide due to _____________ motions, move away from each other due to ___________ motions, and slide past one another at transform faults.
convergent divergent
Earth's largest (strongest) earthquakes occur at ______.
convergent boundaries
As a descending slab in a subduction zone is heated from the outside to the inside as it descends, its ability to produce large earthquakes ______ because the rocks' rigidity ______.
decreases; decreases
When a number of earthquakes occur in a relatively short amount of time, the sequence of events is called a(n) ______.
earthquake cluster
The locations where ruptures in Earth's crust occur as two sides move past each other in earthquake-generating events are called ______.
faults
What evidence was used to determine a large earthquake occurred in the Pacific Northwest of America in 1700? (Select all that apply.)
growth rings in trees indicate trees were killed between 1699 and 1700. Historical records from Japan indicate a tsunami occurred at that time.
Seismic gaps are formed along segments of an active fault that _______.
have not experienced an earthquake in a long time
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
Most earthquakes that occur along fracture zones between segments of midocean ridge occur ______.
on the segments between offset sections of ridge crest
Short, inactive segments along active faults are called _________ __________.
seismic ; gaps
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
At transform plate boundaries, tectonic plates on either side ______ each other.
slide past
The enormous movements that occur along a fault when an earthquake occurs are referred to as ______.
slips
Subduction-zone earthquakes are ______.
sometimes extremely powerful
The average slip rate indicates ______.
the average rate of tectonic motion over a given time period
Earthquakes in the region of Mexico City are caused by ______.
the movements of the Cocos plate as it subducts along a downward thrust fault under the North America plate
An earthquake cluster is ______.
the occurrence of a number of earthquakes in the same region over a relatively short amount of time
At __________ plate boundaries, plates slide past each other horizontally.
transform
Most earthquakes along fracture zones occur on the ______ faults between the offset sections of spreading centers.
transform
The San Andreas fault in California is a ___________ fault
transform
Mantle heat that collects at ______ may cause doming and fracturing in a radial pattern. Gravity may then pull the dome apart and allow magma to well up into the three fracture zones.
triple junctions
The North Anatolian fault has been rupturing in sections with a semiregular pattern to the ______________ since 1939; so it is likely that the next big earthquake will occur near Istanbul.
west