1.
What are Volcanic Hazards?
Correct Answer
A. The dangers posed by volcanic activity
Explanation
This answer is correct because volcanic hazards refer to the various dangers and risks associated with volcanic activity. These hazards include volcanic eruptions, lava flows, ashfall, pyroclastic flows, lahars, and volcanic gases. These hazards can cause significant damage to human settlements, infrastructure, and the environment. Therefore, understanding and studying volcanic hazards is crucial for mitigating their impact and ensuring the safety of communities living near volcanoes. Additionally, while volcanic activity can be dangerous, it also provides environmental benefits such as the creation of fertile soil and geothermal energy sources.
2.
Which type of volcano is characterized by violent eruptions?
Correct Answer
C. Stratovolcanoes
Explanation
Stratovolcanoes are characterized by violent eruptions due to their steep-sided, cone-shaped structure and the presence of viscous magma. These volcanoes are composed of alternating layers of lava, ash, and other volcanic materials, which can lead to explosive eruptions. The high silica content in the magma of stratovolcanoes makes it more viscous, causing gas bubbles to be trapped and build up pressure until a violent eruption occurs. This type of volcano is known for its destructive potential, with eruptions often resulting in pyroclastic flows, ash clouds, and lava flows that can travel long distances.
3.
What is the term for superheated volcanic gas and ash that flows rapidly down a volcano during an eruption?
Correct Answer
B. Pyroclastic flow
Explanation
Pyroclastic flow refers to the superheated volcanic gas and ash that flows rapidly down a volcano during an eruption. This mixture of hot gases, ash, and fragmented rock can reach speeds of hundreds of kilometers per hour, making it extremely dangerous and destructive. Pyroclastic flows can travel down the slopes of a volcano, engulfing everything in their path and causing widespread devastation.
4.
Which of the following is not a risk mitigation strategy for volcanic hazards?
Correct Answer
D. Planting more trees around the volcano
Explanation
Planting more trees around the volcano is not a risk mitigation strategy for volcanic hazards because it does not directly address the primary risks associated with volcanic activity, such as lava flows, pyroclastic flows, and ashfall. While trees can help with erosion control and provide some protection against lahars (mudflows), they do not offer significant protection against the immediate dangers posed by volcanic eruptions. Building stronger infrastructures, evacuation plans, and warning systems are more effective strategies for mitigating the risks and protecting communities from volcanic hazards.
5.
How are lahar hazards managed?
Correct Answer
D. All of the above
Explanation
Lahar hazards are managed through a combination of measures, including creating artificial barriers to divert or contain the flow of lahars, developing hazard maps to identify high-risk areas and inform land-use planning, and educating the public about the risks and appropriate safety measures. All of these approaches are necessary to effectively manage lahar hazards and minimize the potential impact on communities and infrastructure.
6.
Why is monitoring gas emissions important in managing volcanic hazards?
Correct Answer
A. It can indicate an imminent eruption.
Explanation
Monitoring gas emissions is important in managing volcanic hazards because it can indicate an imminent eruption. Volcanic gases such as sulfur dioxide and carbon dioxide are released from magma as it rises to the surface, and changes in gas composition and emission rates can provide valuable information about the state of the volcano. By monitoring gas emissions, scientists can detect any increase in gas concentrations or changes in gas ratios, which may suggest that an eruption is imminent. This information allows for early warning systems to be put in place, enabling the evacuation of nearby communities and the implementation of other necessary safety measures to mitigate the potential hazards.
7.
What organization is responsible for forecasting volcanic eruptions in the U.S?
Correct Answer
C. USGS
Explanation
The correct answer is USGS. The United States Geological Survey (USGS) is responsible for forecasting volcanic eruptions in the U.S. They monitor volcanic activity and provide early warnings to help protect communities near volcanoes. USGS also conducts research to better understand volcanic processes and improve eruption forecasting capabilities.
8.
In volcanic hazard management, what is a hazard assessment used for?
Correct Answer
B. Identifying the potential dangers of an eruption
Explanation
A hazard assessment is used in volcanic hazard management to identify the potential dangers of an eruption. This assessment involves evaluating various factors such as the history of the volcano, its current activity, and the potential impacts on surrounding areas. By identifying the potential dangers, authorities can make informed decisions regarding evacuation plans, emergency response strategies, and other measures to mitigate the impact of the eruption on human lives and infrastructure.
9.
Which volcano caused the largest known death toll due to a volcanic eruption in history?
Correct Answer
D. Mount Tambora
Explanation
Mount Tambora caused the largest known death toll due to a volcanic eruption in history. In 1815, it had a catastrophic eruption that resulted in the deaths of an estimated 71,000 people, both directly from the eruption and indirectly from the aftermath such as famine and disease. The eruption was one of the most powerful in recorded history, causing widespread devastation and a global climate anomaly known as the "Year Without a Summer."
10.
What is the role of a seismometer in managing volcanic hazards?
Correct Answer
B. Detects ground vibrations indicating volcanic activity
Explanation
A seismometer is an instrument used to detect and measure ground vibrations or seismic waves. In the context of managing volcanic hazards, a seismometer plays a crucial role in detecting ground vibrations that indicate volcanic activity. Volcanoes are often associated with seismic activity such as earthquakes and tremors, which can be precursors to volcanic eruptions. By monitoring these ground vibrations, seismometers can provide valuable information about the activity and behavior of a volcano, helping scientists and authorities to better understand and manage volcanic hazards.
11.
Which type of hazard is a 'Jökulhlaup'?
Correct Answer
A. Glacial Outburst Flood
Explanation
A Jökulhlaup is a type of hazard known as a Glacial Outburst Flood. It occurs when a glacier or ice cap rapidly melts or collapses, causing a sudden release of large amounts of water. This can lead to a rapid and powerful flood downstream, carrying with it debris, sediment, and ice. These floods can be extremely destructive, causing significant damage to infrastructure and posing a threat to human lives and ecosystems in the affected areas.
12.
What volcano mitigation strategy involves the redirection of lava flow?
Correct Answer
D. All of the above
Explanation
The correct answer is "All of the above". This means that all three strategies mentioned - aerial bombing, water cooling, and construction of barriers - involve the redirection of lava flow. Aerial bombing can be used to create artificial channels or divert the flow, water cooling involves spraying water on the lava to solidify it and redirect its path, and construction of barriers refers to building physical structures to guide the lava away from populated areas.
13.
What does the VEI (Volcanic Explosivity Index) measure?
Correct Answer
B. The explosiveness of volcanic eruptions
Explanation
The VEI (Volcanic Explosivity Index) is a scale used to measure the explosiveness of volcanic eruptions. It takes into account various factors such as the volume of erupted material, the height of the eruption column, and the duration of the eruption. The scale ranges from 0 to 8, with higher numbers indicating more explosive eruptions. This index helps scientists classify and compare the magnitude of different volcanic events, providing valuable information for hazard assessment and risk mitigation.
14.
What is the primary gas emitted by volcanic eruptions?
Correct Answer
C. Water vapor
Explanation
Volcanic eruptions release a significant amount of water vapor into the atmosphere. This occurs when the intense heat from the eruption causes the water present in the volcano (such as underground water or ice) to turn into steam and be expelled. While volcanic eruptions also release other gases such as carbon dioxide, sulfur dioxide, and nitrogen, water vapor is the primary gas emitted due to the abundance of water in volcanic systems.
15.
What is the use of a "tiltmeter"?
Correct Answer
D. Measure the tilt of the ground surface
Explanation
A tiltmeter is used to measure the tilt of the ground surface. It is a device that can detect and record changes in the angle or slope of the ground. This information is important in various fields such as geology, engineering, and construction, as it helps in monitoring ground stability, detecting potential landslides, and assessing the structural integrity of buildings and infrastructure. By measuring the tilt of the ground surface, a tiltmeter provides valuable data for understanding and predicting geological events and ensuring the safety of structures.
16.
How does satellite remote sensing aid in managing volcanic hazards?
Correct Answer
A. By observing changes in landform and detecting heat anomalies
Explanation
Satellite remote sensing aids in managing volcanic hazards by observing changes in landform and detecting heat anomalies. This is because satellites can capture images of the volcano from space, allowing scientists to monitor any changes in the shape and structure of the land surrounding the volcano. Additionally, satellites can detect heat anomalies, which can indicate the presence of lava or other volcanic activity. By monitoring these changes and anomalies, scientists can better understand the behavior of the volcano and make more accurate predictions about potential hazards, such as eruptions or landslides.
17.
What's the role of Geographic Information System (GIS) in managing volcanic hazards?
Correct Answer
D. All of the above
Explanation
GIS plays a crucial role in managing volcanic hazards as it provides a platform for viewing and analyzing hazard data. It allows scientists and authorities to gather, store, and analyze various types of data related to volcanic hazards, such as topography, land use, and population density. This information helps in mapping the volcano and identifying potential hazards and vulnerable areas. GIS also aids in planning evacuation routes by analyzing the terrain, road networks, and population distribution, ensuring effective and safe evacuation plans. Overall, GIS enables better decision-making and planning for volcanic hazard mitigation and response.
18.
What is the term for a large, bowl-shaped cavity in the ground or on the surface of a planet or the moon, typically one caused by an explosion or the impact of a meteorite?
Correct Answer
A. Crater
Explanation
A crater is a large, bowl-shaped cavity that is formed on the surface of a planet or moon due to an explosion or the impact of a meteorite. It is a common feature found on celestial bodies and is typically characterized by its round shape and depressed center. Craters can vary in size and depth, and they provide valuable information about the geological history and impact events of a planet or moon.
19.
Which type of volcanic hazard is represented by fast-moving, hot clouds of gas, ash, and rock?
Correct Answer
C. Pyroclastic flow
Explanation
A pyroclastic flow is a type of volcanic hazard that consists of fast-moving, hot clouds of gas, ash, and rock. These flows can reach speeds of up to 700 km/h and temperatures of 1,000°C. They are extremely dangerous and can cause significant destruction to anything in their path. Pyroclastic flows are typically associated with explosive volcanic eruptions and can travel for several kilometers, burying everything in their way under layers of ash and debris.
20.
What is the name of the scale used to measure the size and power of earthquakes, which can often be associated with volcanic activity?
Correct Answer
B. The Richter scale
Explanation
The Richter scale is used to measure the size and power of earthquakes. It is often associated with volcanic activity because volcanic eruptions can cause earthquakes. The Richter scale measures the amplitude of seismic waves produced by an earthquake, providing a numerical value that indicates the earthquake's magnitude.