1.
Mauna Loa, an active volcano of the Hawaiian islands, erupted in 1984. The nearest town is Hilo which is 50 km away. Hilo was not evacuated during the eruption. Why not?
Correct Answer
D. Mauna Loa eruptions produce only lava and so pose little or no threat to settlements
Explanation
Mauna Loa eruptions produce only lava and pose little or no threat to settlements. Lava flows from this type of eruption are slow-moving and can be predicted and monitored by scientists. Since Hilo, the nearest town, was 50 km away from the volcano, it was considered to be outside the danger zone and therefore not necessary to evacuate.
2.
About 250 million years ago, almost all of the life on Earth became extinct. There was a massive volcanic eruption that lead to the formation of the Siberian Traps at the same time. Some geographers believe that the eruptions that created this geographical feature came from a hotspot volcano. Which of the following pieces of evidence might help to support that idea?
Correct Answer
C. The Siberian Traps are made up from basaltic lavas
Explanation
The answer is "The Siberian Traps are made up from basaltic lavas." This supports the idea that the eruptions came from a hotspot volcano because basaltic lavas are commonly associated with hotspot volcanism. Hotspot volcanoes are known to produce basaltic lavas, which are low in silica content and have a higher temperature compared to other types of lava. Therefore, the presence of basaltic lavas in the Siberian Traps suggests that the eruptions were likely caused by a hotspot volcano.
3.
The Deccan Traps in India is an area of lava flows created when India was over the same hotspot that powers the large volcano on the Isle of Reunion. Some scientists believe that it could have been responsible for the extinction of the dinosaurs. Which of the following effects would be the most likely to have killed off the dinosaurs worldwide?
Correct Answer
A. The release of large amounts of volcanic gases causing climate change
Explanation
The release of large amounts of volcanic gases causing climate change would be the most likely effect to have killed off the dinosaurs worldwide. Volcanic gases such as carbon dioxide and sulfur dioxide can cause significant changes in the Earth's climate by trapping heat and blocking sunlight. This could have led to a global cooling effect, causing a decrease in temperature and a disruption in the food chain, ultimately leading to the extinction of the dinosaurs.
4.
Underwater hotspot volcanoes are:
Correct Answer
A. Shield volcanoes
Explanation
Underwater hotspot volcanoes are shield volcanoes. Shield volcanoes are formed by the eruption of low-viscosity lava that spreads out in all directions, creating a broad, gently sloping cone-shaped mountain. These volcanoes have a characteristic shield-like shape, hence the name. Hotspot volcanoes occur where there is a stationary source of magma beneath the Earth's surface, creating a hotspot of volcanic activity. As the magma rises, it erupts through the ocean floor, forming underwater shield volcanoes.
5.
The volcanic event that created the Siberian Traps appears to have created a major global warming event. Which of the following gases could have been released?
Correct Answer
A. Carbon dioxide
Explanation
The volcanic event that created the Siberian Traps likely released carbon dioxide. Volcanic eruptions can release large amounts of carbon dioxide into the atmosphere, which can contribute to global warming. Carbon dioxide is a greenhouse gas that traps heat in the Earth's atmosphere, leading to an increase in temperatures. The release of carbon dioxide from volcanic activity can have significant impacts on the climate and environment.
6.
How can you describe the lava from a shield volcano?
Correct Answer
C. Low viscosity and basaltic
Explanation
The lava from a shield volcano is described as having low viscosity and being basaltic. This means that the lava flows easily and spreads out over large areas due to its low resistance to flow. Basaltic lava is also rich in iron and magnesium, which gives it a dark color. This type of lava is commonly found in shield volcanoes, which have gentle slopes and are formed by the accumulation of numerous thin layers of basaltic lava.
7.
Yellowstone National Park in the USA is famous for its hot springs and geysers. It is nowhere near either a destructive or constructive plate boundary so which of the following is the most likely to be the source of heat?
Correct Answer
D. A hotspot
Explanation
A hotspot is the most likely source of heat in Yellowstone National Park. Hotspots are areas of intense volcanic activity that occur in the middle of tectonic plates, far away from plate boundaries. They are believed to be caused by plumes of hot mantle material rising from deep within the Earth. This heat source can create the conditions necessary for the formation of hot springs and geysers, which are prominent features of Yellowstone National Park. The other options, such as the Sun, nuclear waste, and fossil fuels, are not relevant to the geological processes occurring in Yellowstone.
8.
Which of the following is a secondary effect of the eruption of a volcano?
Correct Answer
B. People being killed when the weight of ash on a roof causes it to collapse
Explanation
When a volcano erupts, one of the secondary effects is the weight of ash accumulating on roofs. This heavy layer of ash can cause roofs to collapse, resulting in people being killed. This occurs due to the sheer weight of the ash, which puts excessive pressure on the structure of the roof, leading to its failure. This secondary effect highlights the danger posed by volcanic eruptions and the potential for indirect fatalities caused by the aftermath of an eruption.
9.
The hotspot volcano Piton de la Fournaise is a volcano on the island of Reunion in the Indian Ocean. This is very active and most years, lava from the volcano destroys the road that leads up towards the summit. This is an example of a:
Correct Answer
A. Primary effect
Explanation
The destruction of the road by the lava from the Piton de la Fournaise volcano is considered a primary effect. Primary effects refer to the immediate and direct consequences of a natural event, in this case, the volcanic eruption. The destruction of infrastructure, such as roads, is a direct result of the eruption itself. Secondary effects would be the consequences that occur as a result of the primary effects, such as the displacement of people or economic impacts. Tertiary effects would be the long-term consequences that occur as a result of the primary and secondary effects.
10.
Mauna Kea is a volcano on the largest of the Hawaiian islands which lie in the middle of the Pacific tectonic plate. What type of volcano is it likely to be?
Correct Answer
D. Shield
Explanation
Mauna Kea is likely to be a shield volcano. Shield volcanoes are characterized by their broad, flattened shape and gentle slopes. They are formed by the eruption of fluid lava that flows easily and covers a large area, creating a shield-like structure. Mauna Kea, being located on the Hawaiian islands which are formed by volcanic activity, fits the description of a shield volcano due to its broad shape and the presence of fluid lava flows.