Volcanoes—Nature’s Fireworks

Hey there, curious minds! Let’s embark on an exciting journey to discover the amazing world of volcanoes. Strap on your adventure boots and get ready to be amazed! Volcanoes are majestic mountains with a fiery secret. Deep beneath the Earth’s surface, molten rock called magma builds up over time. When the pressure becomes too intense, the magma bursts out, creating a volcanic eruption. It’s like a natural firework show!

What is a volcano?

A volcano is an opening in a planet or moon’s crust through which molten rock, volcanic ash, and gases trapped under the surface erupt, often forming a hill or mountain.

Volcanic eruptions are partly driven by pressure from dissolved gases. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth’s crust. As the magma rises, pressure decreases, allowing the gases to form bubbles. How the magma (lava) behaves when it reaches the surface depends on both its gas content and chemical composition. Lavas with low silica contents have low viscosities and flow freely, allowing any gas bubbles to escape readily. While lavas with high silica contents are more viscous (resistant to flow), so that any trapped gases escape gradually.

What is silica? Think of beach sand.

Silica, also called silicon dioxide, is a compound of the two most abundant elements in Earth’s crust, silicon and oxygen. The mass of Earth’s crust is 59 percent silica, the principal component of over 95 percent of the known rocks. Silica has three main crystalline varieties, with quartz being, by far, the most abundant variety. Silica sand is used in buildings and roads in the form of portland cement, concrete, and mortar. It also forms sandstone. Silica also is used in grinding and polishing glass and stone; and in the manufacture of glass and ceramics.

Volcanic eruptions are violent and can create colorful and dramatic displays. Volcanoes often form a hill or mountain as layers of rock and ash build up from repeated eruptions.

Volcanoes are classified as active, dormant, or extinct. Active volcanoes have a recent history of eruptions—like Hawaii’s volcanoes; they are likely to erupt again. Dormant volcanoes—like the Cascade Mountains in Washington state—have not erupted for a very long time, but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.

Inside an active volcano is a chamber in which molten rock, called magma, collects. Pressure builds up inside the magma chamber, causing the magma to move through channels in the rock and escape onto the planet’s surface. Once it flows onto the surface, the magma is known as lava.

Some volcanic eruptions are explosive, while others occur as a slow lava flow. Eruptions can occur through a main opening at the top of the volcano or through vents that form on the sides. The rate and intensity of eruptions, as well as the composition of the magma, determine the shape of the volcano.

Volcanoes are found on both land and the ocean floor. When volcanoes erupt on the ocean floor, they often create underwater mountains and mountain ranges as the released lava cools and hardens. Volcanoes on the ocean floor become islands when the mountains become so large they rise above the surface of the ocean. Like the Hawaiian Islands.

Hawaii’s Kilauea (pronounced kil-a-way-ah) volcano, one of the most active on Earth, has been erupting continuously, beginning Jan. 3, 1983. Kilauea erupted 200 years ago, sending speeding lava flows down its peaks and killing over 400 people, including Hawaiian warriors. It was the deadliest volcanic eruption on record in what is now the United States.

Kilauea means “spewing” or “much spreading” in Hawaiian. Which is a perfect name for one of Hawaii’s most awe-inspiring volcanoes.

AIME