Volcanoes are vents or openings in the Earth’s crust that allow molten rock, gases, and ash to escape from beneath the surface. That and molten iron is the stuff this whole earth is made of, and it’s right under your feet, although very far down in most cases.
The word “volcano” is derived from Vulcan, the Roman god of fire.
There are approximately 1,500 active volcanoes worldwide.
The largest volcano on Earth is Mauna Loa in Hawaii, which is also the largest shield volcano. It rises about 13,678 feet (4,169 meters) above sea level and extends about 30,000 feet (9,144 meters) below sea level.
The tallest volcano in the solar system is Olympus Mons on Mars, reaching a height of about 69,841 feet (21,287 meters), almost three times the height of Mount Everest.
Volcanoes can form on land or underwater, with some of the most spectacular volcanic activity occurring beneath the ocean surface.
The eruptions of volcanoes can vary widely, ranging from peaceful lava flows to explosive eruptions that can eject ash, gases, and pyroclastic materials into the atmosphere.
When the Krakatoa volcano erupted in 1883, the sound could be heard 3,000 miles (4,800 km) away.
Volcanic ash can travel long distances, carried by wind currents. The 2010 eruption of Eyjafjallajökull in Iceland disrupted air travel across Europe for several days due to the ash cloud it produced.
Volcanoes are responsible for creating new land, as the lava cools and solidifies over time.
Volcanic eruptions can produce pyroclastic flows, which are fast-moving currents of hot gas, ash, and volcanic materials that rush down the slopes of a volcano.
Your author and his wife had the privilege of walking on brand new real estate that hadn’t existed the day before on the Big Island of Hawaii. We were advised to bring face masks in case the wind direction shifted, wear winter-like clothing to shield us from the heat, and wear boots. Of course most of that clothing isn’t available on Hawaii, but we did dress in layers. As we walked across the dry lava, we could see cracks leading 2 inches (5 cm) down still glowing red.
We came to a river of lava, a pyroclastic flow, and were able to poke 6-foot (2-meter) ohia sticks (a straight hardwood) into the molten lava and pull some out on the instantly flaming sticks. It turned into smooth, hardened glass, with long streamers as drips froze in mid-fall. Our sneakers were smoking, and when we returned, we found that tho soles had slightly melted into new shapes.
The famous volcanic eruption of Mount Vesuvius in 79 AD buried the cities of Pompeii and Herculaneum, preserving them remarkably well.
Some volcanoes exhibit a lava lake, a pool of molten lava that can be observed within the volcano’s crater.
Volcanic lightning, known as “dirty thunderstorms,” can occur during volcanic eruptions due to the electrical charges generated by ash particles colliding in the plume.
The largest volcanic eruption in recorded history was the eruption of Mount Tambora in Indonesia in 1815. It caused the “Year Without a Summer” in 1816, resulting in widespread crop failures and unusually cold temperatures.
The volcanic activity on Io, one of Jupiter’s moons, is the most intense in the solar system. Its surface is covered with hundreds of active volcanoes.
Volcanic eruptions can create unique geological formations, such as volcanic cones, calderas, and lava tubes.
Some volcanoes have produced massive eruptions in the past, known as supervolcanic eruptions. The most recent one occurred about 74,000 years ago at Toba in Sumatra, Indonesia.
Underwater volcanoes, also known as seamounts, can form islands over time when they emerge from the ocean surface.
The deadliest volcanic eruption in history occurred in 1815 on Mount Tambora, killing an estimated 71,000 people.
Some volcanoes, known as “stratovolcanoes” or composite volcanoes, are made up of alternating layers of lava, ash, and rock.
The Hawaiian Islands were formed by a series of volcanic eruptions over millions of years, as the Pacific tectonic plate moved over a hot spot in the Earth’s mantle.