Facts About Volcanoes that You Didn’t Know

Facts About Volcanoes Part 1

1. Most volcanoes on Earth are actually underwater.

2. Depending on the size and the scale of its eruption, a volcano can kill everything for miles around it and can even affect people thousands of kilometers away from it.

3. Mount Vesuvius has erupted multiple times in history, most recently in 1944.

4. Before the current definition of a volcano was created, many objects like river gorges and even geysers were considered to be volcanoes.

5. The eruption of Cerro Azul volcano in Chile on May 4, 2015, generated lava fountains reaching heights of up to 30 meters (100 feet).

6. Mount Vesuvius is famous for its 79 AD eruption that buried the cities of Pompeii and Herculaneum under ash, killing all their inhabitants. In addition to being one of the most lethal volcanic eruptions ever recorded, it is also one of the best-preserved ones.

7. The first person to understand that volcanoes were made by the eruption of heated material from the Earth’s interior was the Italian philosopher and scientist Giordano Bruno, who was burned at the stake for his beliefs.

8. The word volcano comes from Vulcano, a volcanic island in Italy that was named after Vulcan, the god of fire in Roman mythology.

9. Iceland is home to more than 20 subglacial volcanoes known as hyaloclastite islands. These are volcanoes formed by lava filling in holes created by erosion under glaciers or ice sheets. Some subglacial volcanoes have erupted so recently that their lava is still warm when it reaches the surface of Earth.

10. The first-ever active underwater volcano was discovered in 1997 by a team of US scientists. It was located directly below an oceanic Monterey Bay National Marine Sanctuary in California, USA.

11. The largest active volcano on the planet is Mauna Loa on the island of Hawai’i, with a height of 12,169 feet (3,776 meters). The inactive Mauna Kea volcano has a height of 13,796 feet (4,205 meters)

12. The only active volcano on the African continent is Erta Ale in the Danakil Desert. It is the most remote volcano on Earth, located 517 miles (832 kilometers) from the nearest human settlement.

13. The most recent eruption of Mount Vesuvius was in 1944. However, it hasn’t erupted for the last 2,000 years! Geologists expect an eruption of Vesuvius in our lifetime, however.

14. Volcanologists are people who study volcanoes and their eruptions. They are also known as volcanologists or vulcanologists (from Vulcan).

15. The first volcanologist was the Sicilian scientist Giuseppe Mercalli, who studied volcanoes in Italy and Sicily. His work helped determine how earthquakes were related to volcanic eruptions.

16. Since its discovery in 1979, Mt St Helens is the most active volcano in the US state of Washington.

17. In 2006, an underwater volcano off the coast of Tonga erupted for the first time in recorded history, forcing several countries to close their airspace over the area until they were sure there was no danger to airplanes traveling through it. The eruption lasted about one month and produced emissions that could be seen from space.

18. There are two active underwater volcanoes near Japan: Sakurajima and Iwo Jima. They both produce smoke that can be seen from space.

19. Since the beginning of time, there have been more than 1,000 types of volcanoes identified.

20. Scientists believe that there may be as many as 2 million volcanoes on Earth, some of which are located in the ocean ridges and deep-sea trenches.

21. There are two active underwater volcanoes near New Zealand: White Island and Monowai Caldera, both of which emit smoke and steam above the water’s surface on a regular basis.

22. Kīlauea is the most active volcano on Earth. It has been erupting continuously since 1983 and currently produces enough lava each year to fill up an Olympic-sized swimming pool.

23. The first solid evidence that volcanic activity may have happened on Mars came in 2008 when NASA discovered deposits of a mineral called opaline silica glass in a crater near the planet’s south pole. This silica was found to have been released by molten rock from volcanic eruptions and remained on the surface of Mars for hundreds of thousands of years until it was covered by dust or ice and preserved there.

24. Since the beginning of time, there have been more than 1,000 types of volcanoes identified.

25. Volcanic eruptions have been happening for over 640 million years, ever since the formation of the planet. This means that volcanoes are a lot older than many other features of Earth-like mountains and ocean basins.

26. One of the most massive volcanic eruptions in history happened on Indonesia’s island of Krakatoa in 1883, when about 150 cubic kilometers (40 cubic miles) of ash was released from a single vent eruption that lasted about 3 days.

27. Supervolcanoes are volcanoes that are capable of producing an eruption on a scale that is vastly greater than anything ever seen in human history. These eruptions could produce enough ash to cover the entire planet and would almost certainly be responsible for the extinction of most life on Earth.

28. The only active volcano on the African continent is Erta Ale in the Danakil Desert. It is the most remote volcano on Earth, located 517 miles (832 kilometers) from the nearest human settlement.

29. Thirty-five million years ago, a supervolcano located in what is now Yellowstone National Park erupted, creating an ash cloud that stretched across North America to as far away as New York and Washington DC!

30. The most deadly eruption in history was the 1815 eruption of Mt Tambora that killed more than 100,000 people. The explosion was so powerful that it created tsunamis across the Indian Ocean that were measured up to 20 meters (66 feet) high.

31. The only continent without a single active volcano in Antarctica.

32. Kīlauea is the most active volcano on Earth and in the United States, releasing about 1,000 cubic meters (35,300 cubic feet) of lava every single day!

38. The force of a volcanic explosion can hurl solid rock and dust from the crater to far outdistances.

Facts About Volcanoes Part 2 – Trivia Questions with Answers

1. When do Pyroclastic Flows happen?
Answer: When there is an explosive eruption

2. How long do Pyroclastic Flows last?
Answer: Less than one minute

3. What happens to rock during volcanic eruptions?
Answer: Rock is melted, eroded, and subjected to high temperatures

4. Volcanic gases may contain a variety of different toxic substances such as:
Answer: chlorine, fluorine, sulfur dioxide
hydrogen chloride, sulfur dioxide, oxides of nitrogen

5. What is the Leiden spine in volcanology?
Answer: The Leiden spine is defined as an apparent change in slope on the profile of a lava flow caused by changes in flow rate and/or fluid content at its base when it becomes too thick to flow easily around obstacles such as houses or trees.

6. What is the pyroclastic density current?
Answer: A mass of hot gas, ash, rock, and other debris moved by a violent rush of gas down the side or at the front of an erupting volcano. The word “pyroclastic” means “fire-broken”.

7. At what distance are humans safe from the effects of volcanic ash?
Answer: About 20 km or 12 miles away from an erupting volcano.

8. When did the Icelandic volcanic eruption last kill someone?
Answer: In 1783, the Laki volcano in Iceland erupted for 8 months and killed 9–10% of Iceland’s population. It was also blamed for the freezing temperatures in Europe during that year.

9. The most recent major volcanic eruption in Iceland happened in?
Answer: In 2014, there was a fissure eruption in the Holuhraun lava field

10. What is a lahar?
Answer: A lahar is a mudflow or debris flow composed of at least 50% volcanic material and rock fragments. The material flows down the side of the volcano or across nearby land.

11. What is ignimbrite?
Answer: Ignimbrite is a deposit: typically of pumice, welded tuff, and ash, formed from the explosive eruption of magma; the fine-grained equivalent of pyroclastic flow.

12. What is a pyroclastic flow?
Answer: A hot, fast-moving current of gas and rock fragments (called tephra) that travels down the side of a volcano. It may be caused by an explosion or by pressure built up behind the base of a growing cone pushing blocks and ash forward.

13. What is a phreatic eruption?
The phreatic eruption is when a body of molten rock (magma) from the Earth’s lower crust or mantle is suddenly injected into an overlying body of water, either directly or via groundwater, causing the water to boil, turn to steam, and rise rapidly. The sudden combination of hot steam and cold air may produce a forest fire-like effect in which burning trees seem to be ablaze without an apparent cause. This type of eruption is very dangerous as it results in little to no warning. It can cause rapid destruction and death, as when Mt. St Helens erupted in 1980.

14. What is the process of lava cooling?
Answer: It is when lava changes from a liquid to a solid-state.

15. What happens when lava cools?
Answer: When lava cools, it shrinks and cracks for the same reason that a glassblower observes as his tube shrinks and cracks while blowing air through it. These cracks are known as “fissures”. If enough fissures develop, the interior of an active lava flow can be broken into dozens of separate fragments and flows that may continue to move forward on top of one another.

16. How does an eruption affect new rock?
Answer: The more powerful the eruption, typically, the more violent it is. This affects how long it takes for new rock to form because violently erupting volcanoes will have more ash and lava, which will reduce the mineral content in new rocks. A less powerful but longer-lasting eruption would take years to create new rocks with little ash or lava deposits. Large amounts of water also have a negative effect on how quickly new rock will form because they wash away minerals from newly erupted material and cools the area down to a temperature where liquid water can’t exist at room pressure level.

17. What is the temperature of lava when it erupts?
Answer: About 1400 °C (2550 °F)

18. Where does magma come from?
Answer: Magma comes from the mantle, which is below the crust. It then rises through a column of rock called the “crust” or “lithosphere” and enters into a magma chamber.

19. What are pyroclastic flows made of?
Answer: Pyroclastic flows are made out of hot gas, ash, rock fragments, and other debris.