Volcanoes are both amazing geological wonders and terrifyingly dangerous, so it’s no wonder that many people are fascinated by them! From their impact on the typography of our world, to their massive size, to all the different types of violent eruptions that can occur, volcanoes are truly a force of nature. But beyond some basic facts about famous eruptions and a model you made in class as a kid, what do you really know about them? We’ve rounded up six fascinating facts about volcanoes to jump-start your learning! So, are you ready to discover some new facts about volcanoes? Let’s dive in!
#1 Over 80% of Earth’s Surface Is of Volcanic Origin.
More than 80% of Earth’s surface is of volcanic origin – that includes the surface above and below sea level. The countless volcanic eruptions that have occurred over time are responsible for producing mountains, plateaus, and plains, which later eroded and weathered into the majestic landscapes we see today.
#2 There Are Approximately 1,500 Potentially Active Volcanoes on Earth.
The US Geological Survey reports that there are approximately 1,500 potentially active volcanoes on Earth, not counting the continuous belts of volcanoes located on the ocean floor at spreading centers like the Mid-Atlantic Ridge. Of those potentially active volcanoes identified, around 500 have erupted in historical time. A large number of those erupting volcanoes are located along the Pacific Rim, in what is known as the “Ring of Fire.” Some – but certainly not all – of the 169 potentially active volcanoes located in the United States are within the “Ring of Fire.”
#3 There Are Different Types and Styles of Volcanic Eruptions.
Scientists classify volcanic eruptions into several types and styles. The two main types are effusive eruptions, in which magma rises through the surface and flows out of the volcano in the form of lava, and explosive eruptions, in which magma is torn apart as it rises and reaches the surface in pieces called pyroclasts. In addition to these two main types, there are also various styles of eruptions.
Some eruption styles are named for specific locations while others are named for the shape of the eruptive products. Hawaiian eruptions are a style of eruption in which fluid basaltic lava is thrown into the air from a vent (or line of vents). This can go on for days, giving rise to the name “fire fountains.” Hawaiian eruptions are named for the Kilauea Volcano on the Big Island of Hawaii, which famously produces this type of eruption. Vulcanian eruptions are short and violent, but relatively small explosions of viscous magma. They’re named for the Italian island of Vulcano, where a small volcano was once thought to be directly above the forge of the Roman god, Vulcan. Plinian eruptions are the largest and most violent – they are named for Pliny the Younger, who observed the 79 AD eruption of Mount Vesuvius. Plinian eruptions are so powerful that they can even obliterate the entire top of a mountain, as occurred in the 1980 eruption of Mount St. Helens. Other types of eruptions include Surtseyan eruptions, lava domes, and Strombolian eruptions.
#4 Not All Lava Is the Same Temperature.
All lava is exceedingly hot, but specific temperatures can vary widely and depend in part on the chemical composition of the molten rock. This means that lava temperatures can vary from roughly the same level of heat as the inside of a pizza oven to off-the-charts hot. Felsic or rhyolitic magma is roughly 1,112 to 1,472 degrees Fahrenheit. An intermediate type of magma typically comes in at a temperature between 1,472 to 1,832 degrees Fahrenheit. Mafic or basaltic magma gets the hottest, reaching temperatures between 1,832 and 2,192 degrees Fahrenheit.
#5 Lava Colors Correlate to Temperature.
The color of molten rock (lava) correlates to its temperature. Lava that glows red is usually in the felsic temperature range of 1,112 to 1,472 degrees Fahrenheit. Molten rock that glows orange is slightly hotter, falling within the intermediate temperature range of 1,472 to 1,832 degrees Fahrenheit. Molten rock that glows yellow is the hottest, falling into the mafic temperature range of 1,832 to 2,192 degrees Fahrenheit.
#6 The Largest Active Volcano in the World Is Located in the United States.
Currently, the largest active volcano on Earth is located in the United States. It is Hawaii’s Mauna Loa. This massive volcano rises more than 4 km (2.5 mi) above sea level, while its submarine flanks descend an additional 5 km (3 mi) to the sea floor (which is actually depressed 8 km (5 mi) due to Mauna Loa’s mass). This means the volcano’s summit is approximately 17 km (10.5 mi) above its base. While it is the largest active volcano, Mauna Loa is not the most dangerous volcano in the United States. The US Geological Survey rates Kilauea, a continuously erupting volcano in Hawaii, as the most dangerous. Rankings are based on how much damage an eruption would do and each volcano gets two scores: an overall threat score and an aviation threat score. Kilauea earned an overall threat score of 263 and an aviation threat score of 48. The second most dangerous volcano located in the United States is Mount St. Helens in Washington, which erupted in 1980 and killed 57 people. The US Geological Survey most recently gave Mount St. Helens an overall threat score of 235 and an aviation threat score of 59.
Want to learn even more facts about volcanoes? Then check out this video!
Still not enough science facts to satisfy your curiosity about the Earth? Keep learning with our article about earthquakes!