Could you outrun a lava flow? Take the everything volcanoes quiz!
Rushing lava. Wild flames. Devastation and destruction. Those images are iconic representations of a volcano, but are they the whole story? Do all active volcanoes lead to such ruin? What causes volcanoes to erupt in the first place?start quiz
Question 1 of 20
How much variation in destructive power is there among volcanoes?
... Volcanoes differ greatly in the amount of damage they cause. Lava can burst out of one and, in minutes, the surrounding area is devastated. On the other hand, during some eruptions you can simply walk away and avoid flowing lava.
Question 2 of 20
Magma is a ________.
... Magmas is fluid molten rock below the earth's surface. It's a stew of liquids, solids and gases.
Question 3 of 20
Which part of the Earth melts to form magma?
... The second geological layer of the Earth, the mantle, is normally very hot, yet solid because of extreme pressure. When volcanoes form, though, the mantle does melt.
Question 4 of 20
Why does magma erupt?
... Part of the composition of magma is dissolved gasses. When pressure of the gas exceeds the pressure of the rock encasing the magma, the gas expands and forms bubbles. These eventually escape, taking the magma with them.
Question 5 of 20
Which type of magma produces a more explosive eruption?
... Magma that is very viscous (doesn't flow easily) makes it harder for gas bubbles to escape. Therefore, the bubbles will take more magma out of the volcano with them. Magma with less viscosity (flowing more easily) allows the bubbles to readily escape, so the eruption is less intense.
Question 6 of 20
Slow-moving lava is referred to as _________.
... "Effusive" lava is destructive to the environment it encounters. Its slow speed renders it relatively harmless to people, however, because they can avoid the flow.
Question 7 of 20
Rocks that are solid lava are __________.
... Pyroclastic rocks are solid volcanic matter. They are often found in the initial explosion of a volcano, along with gas and ash.
Question 8 of 20
The type of eruption that destroyed the ancient city of Pompeii was _________.
... Mt. Vesuvius wiped out Pompeii in 79 A.D. during a "plinian" eruption. This is characterized by magma that is very viscous, with a high gas content. The gases can push volcanic matter 30 feet (9 meters) above the surface. The lava flow is swift and destructive.
Question 9 of 20
Which of the following types of eruption does not usually have a lava flow?
... Vulcanian eruptions are characterized by short, gaseous bursts. They throw out ash and large pyroclastic rocks, but not lava.
Question 10 of 20
Many volcanoes with a "scoria cone" shape erupt ______.
... Scoria cone volcanoes are the most common shape. The sides are steep and the opening is wide. Many erupt only once.
Question 11 of 20
What often forms when a "caldera" structure is created by a volcano?
... A caldera forms when a volcano collapses in on itself, forming a round basin. Water gathers there and creates a lake.
Question 12 of 20
In the movie Joe Versus the Volcano (1990), Joe, played by Tom Hanks, is recruited to jump into a volcano because ________.
... In the film, industrialist Samuel Graynamore needs the mineral "bubaru" to manufacture superconductors. It is available on a Pacific Island, but before it can be mined, the island's residents want a sacrificial volunteer to appease the island's volcano.
Question 13 of 20
What happens when Joe's volcano erupts?
... After Joe and his new wife jump into the volcano, it erupts and hurls them to relative safety in the ocean, where they are later rescued. The volcano's island sinks.
Question 14 of 20
During the last 200 years, about how many volcanic eruptions have killed more than 1,000 people?
... There have been about 20 volcano eruptions in the last two centuries that have directly led to tremendous loss of human life.
Question 15 of 20
Ninety percent of volcanoes are located within the "Ring of Fire," which is in the ________.
... The Ring of Fire, located in the Pacific Ocean, is composed of collided tectonic plates that form a 25,000 mile circle in which there is high volcanic activity.
Question 16 of 20
Which country has the most people living near active volcanoes?
... Indonesia has 129 active volcanoes spread around the country. One Indonesian island, Java, has 30 volcanoes looming over 120 million people.
Question 17 of 20
One of the volcanoes on Java is "Merapi," which means "___________."
... Merapi, the "fire mountain," is almost 10,000 feet tall (3,048 meters) and is very active.
Question 18 of 20
The theory of plate tectonics, which is used to explain volcanoes, was developed ___________.
... Scientists developed the concept of plate tectonics during the 1960s. It depicts the Earth's outer surface divided into sections that shift incredibly slowly.
Question 19 of 20
Which natural disaster can be caused by a volcano?
... If mountains surrounding an erupting volcano are covered with snow, that snow can quickly melt, causing mud flows that can cover both the natural landscape and human settlements.
Question 20 of 20
Most of the volcanoes that are highest above sea level are in the ___________ Mountains.
... Fewer than 100 volcanoes lie above 5,000 meters. Most of them are in the central part of the Andes Mountains in South America.
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