Question 1

Several recent earthquakes in Washington's Puget Sound region were caused by movement of the subducting ______________ plate.

Accepted Answer

The Puget Sound region is located in the Cascadia subduction zone, where the Juan de Fuca plate is subducting beneath the North American plate. Therefore, the earthquakes in this region are mainly caused by the movement of the subducting Juan de Fuca plate.

Question 2

If Alaska and California are ignored,the list of 10 largest U.S.earthquakes shows ____________.

Accepted Answer

The answer of If Alaska and California are ignored,the list...

Question 3

The New Madrid earthquakes are apparently related to ______________.

Accepted Answer

The New Madrid earthquakes occurred in an area that is located along an old buried rift zone, where the North American Plate and the Mid-Continent Rift System diverged over a billion years ago. This old rift zone is still seismically active today and is believed to be the cause of the New Madrid earthquakes.

Question 4

Paleoseismologic analysis of trenches cut across faults and folds in the New Madrid,Missouri,area has led the U.S.Geological Survey to forecast a 90% chance of a magnitude ______ earthquake here within the next 50 years.

Accepted Answer

The U.S. Geological Survey forecasts a 90% chance of a magnitude 6 to 7 earthquake in the New Madrid, Missouri, area within the next 50 years based on paleoseismologic analysis. This region is known for its seismic activity due to the New Madrid Seismic Zone.

Question 5

The dominant type of faulting in the Great Basin region is ______________.

Accepted Answer

The Great Basin region is characterized by the Basin and Range Province, which is dominated by normal faulting. This means that the blocks of crust are dropping down along faults, forming mountains and valleys. Reverse faulting (where the blocks move up) is less common in this region. Strike-slip and thrust faulting are also present but less dominant than normal faulting. Transform faulting, which involves lateral movement along a fault, is not common in this region.

Question 6

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 8.3.

Accepted Answer

The San Andreas fault segment between Cholame and San Bernardino broke loose at its northwestern end on 9 January 1857, causing the Fort Tejon earthquake with a magnitude of about 8.3.

Question 7

The state (other than Alaska)most likely to have a magnitude 9 or larger earthquake in the next several hundred years is ______________.

Accepted Answer

Washington is located on the Cascadia subduction zone, which has the potential to produce large earthquakes. In fact, the most recent magnitude 9 earthquake in the United States occurred in the Cascadia subduction zone in 1700. While California is also a seismic hot spot, the question specifically mentions a magnitude 9 or larger earthquake, of which there is currently no known active fault capable of producing such an event in California. Missouri, Nevada, and South Carolina are not located near any known active faults capable of producing such large earthquakes.

Question 8

The crustal thickness in the Great Basin is ____________________.

Accepted Answer

The crustal thickness in the Great Basin is generally thicker than oceanic crust due to its continental nature, but it is thinner than the Mid-continental North American crust, which is part of the stable interior of the continent known for its relatively thick crust.

Question 9

Which state accounts for the greatest percentage of all U.S.earthquakes of magnitude 3.5 and above?

Accepted Answer

Alaska accounts for the greatest percentage of all U.S. earthquakes of magnitude 3.5 and above, due to its location on the boundary of the Pacific and North American tectonic plates, making it highly seismically active.

Question 10

Which of the following represents evidence for major fault movement on the Seattle fault zone about 1100 years ago?

Accepted Answer

All of these pieces of evidence point to major fault movement on the Seattle fault zone about 1100 years ago. The uplift at Restoration Point suggests vertical movement caused by faulting, the landslides indicate shaking and ground movement, the tsunami deposits indicate sudden displacement of large volumes of water which could be caused by faulting, and the rock avalanche ages suggest a regional seismic event. Together, these pieces of evidence provide a strong case for major fault movement in the area around 1100 years ago.

Question 11

The Great Basin region between the eastern Sierra Nevada in California and the Wasatch Mountains in Utah ______________________ in response to plate tectonic forces.

Accepted Answer

The Great Basin region has expanded in an east-west direction due to extensional tectonics, which is a result of the stretching and thinning of the Earth's crust in this area.

Question 12

Which of the following states has the highest earthquake risk?

Accepted Answer

Arkansas is located near the New Madrid fault zone, which is one of the most active seismic zones in the United States. Therefore, it has a higher earthquake risk than the other states listed.

Question 13

On 3 November 2002,a large earthquake occurred in __________.Because of its similarity to the 1857 Fort Tejon earthquake on the San Andreas fault,this event has been compared to the much-anticipated "Big One" in Southern California.

Accepted Answer

The earthquake that occurred on 3 November 2002 and has been compared to the "Big One" in Southern California happened in Alaska, making option C the correct answer.

Question 14

Which of the following states has the lowest earthquake risk?

Accepted Answer

Florida has the lowest earthquake risk among the options listed. It is geologically stable and does not have significant seismic activity compared to the other states mentioned.

Question 15

The 17 January 1994 Northridge earthquake in Los Angeles was generated on a _______ thrust fault.

Accepted Answer

The Northridge earthquake was generated on a blind thrust fault, meaning it did not break the surface and was not visible.

Question 16

California accounts for _______ of all U.S.earthquakes of magnitude 3.5 and above.

Accepted Answer

The answer of California accounts for _______ of all U.S.earthquakes...

Question 17

At Hebgen Lake in 1959 an earthquake larger than magnitude 7 greatly affected ____________.

Accepted Answer

The Hebgen Lake earthquake in 1959 had a magnitude larger than 7 and had a significant impact on areas in and around Yellowstone National Park, including causing a large landslide that blocked the Madison River and formed Quake Lake.

Question 18

Which four states account for 91% of all U.S.earthquakes of magnitude 3.5 and above?

Accepted Answer

California, Alaska, Hawaii, and Nevada are the four states that account for the majority of significant earthquakes in the U.S. due to their locations along tectonic plate boundaries and fault lines.

Question 19

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 1680.

Accepted Answer

The Coachella Valley segment of the San Andreas fault is the only one mentioned that has not experienced a long rupture in historic times. Historical records and geological evidence indicate that this segment has a history of rupturing approximately every 250 years on average, with the last significant movement occurring in 1680.

Question 20

When compared to California,seismic energy in the eastern U.S.is ______________.

Accepted Answer

Seismic energy in the eastern U.S. is transmitted more effectively in the older, more solid rocks compared to California. This is because the geological structures in the eastern U.S. are older and more continuous, allowing seismic waves to travel farther without losing as much energy.

Quiz 5: Earthquakes Throughout the United States and Canada