1.
A “100 year” flood is:
Correct Answer
E. A flood with a 1% probability of occurring within a given year.
Explanation
A "100 year" flood refers to a flood with a 1% probability of occurring within a given year. This means that in any given year, there is a 1% chance of experiencing a flood of this magnitude. The term "100 year" flood is used to describe the frequency of occurrence rather than the actual duration or impact of the flood. It is a way to quantify the likelihood of a flood happening and is commonly used in flood risk assessment and planning.
2.
What characteristic of magma is the main control as to whether it will erupt as a lava
flow or an explosive eruption?
Correct Answer
A. Amount of dissolved gases
Explanation
The main control as to whether magma will erupt as a lava flow or an explosive eruption is the amount of dissolved gases. When magma has a high concentration of dissolved gases, such as water vapor, carbon dioxide, and sulfur dioxide, it creates pressure within the magma chamber. If the pressure becomes too great, it can cause a violent explosive eruption. On the other hand, if the amount of dissolved gases is relatively low, the magma can flow more easily and result in a lava flow eruption.
3.
Love waves are best described as:
Correct Answer
B. Surface waves that cause the ground to move laterally, side-to-side
Explanation
Love waves are a type of surface wave that cause the ground to move laterally, side-to-side. Unlike body waves, which travel through the Earth's interior, surface waves travel along the Earth's surface. Love waves are characterized by their horizontal motion, creating a shaking or swaying motion in the ground. This lateral movement is what distinguishes Love waves from other types of surface waves or body waves.
4.
Mudslides composed of a mixture of water and various sizes of volcanic rock, along
with varying amounts of plant debris, are called:
Correct Answer
E. Lahars
Explanation
Lahars are mudslides that occur when volcanic materials, such as ash and rock, mix with water. These mixtures can vary in size and composition, often containing plant debris as well. Unlike pyroclastic flows, which are composed of hot ash and gas, lahars are cooler and slower-moving. Pahoehoe flows refer to smooth lava flows, volcanic collapses are sudden failures of volcanic structures, and lava tubes are tunnels formed by flowing lava. Therefore, the correct answer is lahars.
5.
In a meandering stream, erosion occurs mainly:
Correct Answer
B. Laterally, toward the outside of the meander bend.
Explanation
In a meandering stream, erosion occurs mainly laterally, toward the outside of the meander bend. This is because the water flow is faster on the outer side of the bend, creating a higher velocity and stronger erosive force. The water erodes the outer bank, causing it to collapse and form a cut bank. At the same time, deposition occurs on the inner side of the bend where the water flow is slower, leading to the formation of a point bar. This lateral erosion and deposition process is responsible for the meandering shape of the stream over time.
6.
True or False? Buildings made of concrete blocks are better capable of withstanding
shaking from an earthquake than are buildings made of wood.
Correct Answer
B. False
Explanation
Buildings made of concrete blocks are not better capable of withstanding shaking from an earthquake than buildings made of wood. This is because wood is a more flexible material, allowing it to absorb and distribute the energy from the earthquake more effectively. Concrete, on the other hand, is a rigid material that can crack and collapse under the intense shaking of an earthquake. Therefore, buildings made of wood are generally considered to be more resilient in seismic events.
7.
The most important factor controlling the nature of a given flood is:
Correct Answer
D. The value of discharge per unit area of stream
Explanation
The value of discharge per unit area of the stream is the most important factor controlling the nature of a given flood. This is because it determines the amount of water flowing through a specific area of the stream. A higher discharge per unit area indicates a larger volume of water, which can lead to a more severe flood. Conversely, a lower discharge per unit area indicates a smaller volume of water, resulting in a less severe flood. Therefore, the value of discharge per unit area of the stream directly influences the nature and magnitude of a flood.
8.
According to the video “Inside the Volcano”, the eruption of the volcano island Thera,
on what is now known as Santorini, resulted in the collapse of which ancient civilization?
Correct Answer
B. Minoans
Explanation
The eruption of the volcano island Thera, now known as Santorini, resulted in the collapse of the Minoan civilization.
9.
On average, how many great earthquakes (Magnitude equal to or greater than 8)Â
occur globally each year?Â
Correct Answer
A. 1
Explanation
The correct answer is 1 because great earthquakes with a magnitude equal to or greater than 8 are rare events. On average, there is usually only one such earthquake globally each year. These earthquakes are highly destructive and can cause significant damage and loss of life.
10.
Most damage caused by earthquakes result from:
Correct Answer
D. Surface waves
Explanation
Surface waves are the correct answer because they are the slowest and most destructive type of seismic waves. These waves travel along the Earth's surface and cause the ground to move in a rolling motion, resulting in the most damage to buildings and infrastructure. Surface waves have a larger amplitude than other types of waves, which amplifies their destructive power. They are responsible for producing the majority of the shaking and destruction during an earthquake.
11.
The video “California’s Katrina” discusses the possibility of catastrophic flooding in
which California city?
Correct Answer
B. Sacramento
Explanation
The video "California's Katrina" discusses the possibility of catastrophic flooding in Sacramento.
12.
True or False? Compared to downstream floods, upstream floods typically result in
fewer deaths but more property damage.
Correct Answer
B. False
Explanation
Upstream floods typically result in fewer deaths but more property damage. This is because upstream floods occur in less populated areas, where there are fewer people at risk of drowning. However, these floods can cause significant damage to infrastructure, buildings, and agricultural land as the force of the water increases downstream. Therefore, the given answer is incorrect.
13.
Which features characterize the upstream portions of a typical river?
Correct Answer
E. A and b but not c
Explanation
The correct answer is "a and b but not c." The upstream portions of a typical river are characterized by a steep gradient and a narrow flood plain. This means that the river has a rapid descent and flows through a narrow channel, resulting in a higher velocity and more erosive power. Meanders, on the other hand, typically occur in the middle and lower portions of a river where the gradient is gentler. Therefore, meanders are not a characteristic of the upstream portions of a typical river.
14.
Which natural hazard is NOT covered by home owners insurance?Â
Correct Answer
B. Flood damage
Explanation
Home owners insurance typically does not cover flood damage. This is because flood damage is considered a separate type of insurance and is usually covered by a separate policy, such as flood insurance provided by the National Flood Insurance Program (NFIP) in the United States. This is because flood damage can be widespread and costly, and therefore requires specific coverage.
15.
According to the video “Inside the Volcano”, the style of eruption of Mt. Vesuvius in
79 A.D. is called:
Correct Answer
C. Plinian
Explanation
The correct answer is Plinian. The video "Inside the Volcano" provides information about the eruption of Mt. Vesuvius in 79 A.D. The style of eruption during that time was characterized as Plinian.
16.
Ground motion caused by a magnitude 7 earthquake is how many times greater than
that caused by a magnitude 4 earthquake?
Correct Answer
E. 1,000 times
Explanation
The ground motion caused by a magnitude 7 earthquake is 1,000 times greater than that caused by a magnitude 4 earthquake. This is because the magnitude scale is logarithmic, meaning that each whole number increase in magnitude represents a tenfold increase in the amplitude of the seismic waves. Therefore, a magnitude 7 earthquake has 1,000 times more ground motion than a magnitude 4 earthquake.
17.
Urbanization of an area may lead to increased flooding by:
Correct Answer
D. All the above
Explanation
Urbanization can lead to increased flooding due to various factors. One factor is the covering of porous and permeable soil with streets and parking lots, which reduces the amount of rainwater that can be absorbed into the ground and increases the amount of runoff. Another factor is the installation of storm sewers, which decreases the time it takes for water to reach a stream channel, leading to faster and more intense flooding. Additionally, elevating structures built on floodplains reduces the available storage capacity for floodwaters, causing them to rise even higher. Therefore, all of the given options contribute to increased flooding in urban areas.
18.
True or False? The intensity of an earthquake varies with distance from the epicenter,
but the magnitude is a fixed value, determined by the amount of ground movement at the
epicenter.
Correct Answer
A. True
Explanation
The intensity of an earthquake refers to the amount of shaking and damage caused by the earthquake at a specific location. It is influenced by various factors, including the distance from the epicenter. As the distance from the epicenter increases, the intensity of the earthquake generally decreases. On the other hand, the magnitude of an earthquake is a fixed value that represents the total amount of energy released by the earthquake. It is determined by the amount of ground movement at the epicenter and is not affected by the distance from the epicenter. Therefore, the statement is true.
19.
According to the video “Inside the Volcano,” the ancient cities of Pompei and
Herculaneum were destroyed by what kind of eruptive product from Mt. Vesuvius?
Correct Answer
B. Pyroclastic flows and falls
Explanation
The correct answer is pyroclastic flows and falls. According to the video "Inside the Volcano," the ancient cities of Pompei and Herculaneum were destroyed by pyroclastic flows and falls from Mt. Vesuvius. Pyroclastic flows are fast-moving currents of hot gas and volcanic matter, including ash, rocks, and debris. These flows can reach temperatures of up to 1,000 degrees Celsius and can travel at speeds of over 100 kilometers per hour. Pyroclastic falls, on the other hand, occur when volcanic ash and rock fragments are ejected into the air and then fall back to the ground. These devastating volcanic phenomena were responsible for the destruction of the cities.
20.
True or False? Data upon which the Flood Recurrence Interval for a given stream are
based are specific to that stream and will not change over time.
Correct Answer
B. False
Explanation
The statement is false because the data upon which the Flood Recurrence Interval for a given stream is based can change over time. Factors such as climate change, land use changes, and alterations to the stream's watershed can all impact flood recurrence. Therefore, it is important to regularly update and reassess the data to ensure accurate flood predictions and planning.
21.
Some volcanoes produce fast-moving avalanches of ash, rock, volcanic glass
fragments, and gas. What are these avalanches called?
Correct Answer
D. Pyroclastic flows
Explanation
Pyroclastic flows are fast-moving avalanches of ash, rock, volcanic glass fragments, and gas. They are extremely dangerous and can reach speeds of up to 700 km/h. These flows are formed during explosive volcanic eruptions when the eruption column collapses, sending a mixture of hot volcanic materials rushing down the slopes of the volcano. Pyroclastic flows can cause widespread destruction and are a significant hazard associated with volcanic eruptions.
22.
According to the video “California’s Katrina”, flooding of New Orleans could not
have been prevented; the design and construction of the levees protecting the city were
sound.
Correct Answer
B. False
Explanation
The explanation for the correct answer, which is False, is that the video "California's Katrina" argues that the flooding of New Orleans could have been prevented. It states that the design and construction of the levees protecting the city were not sound, implying that they were flawed and contributed to the flooding.