Volcanoes
Sleeping Giants
Volcanoes serve as Earth’s geologic sculptors, creating over 80 percent of the planet’s surface, thus providing a platform for life to flourish.
Deep inside the Earth, the intense heat causes some rocks to melt into a thick fluid known as magma. Magma, being lighter than the surrounding solid rock, rises and accumulates in magma chambers. Over time, some magma finds its way through vents and fissures to the Earth’s surface. Once magma erupts, it’s termed lava. As lava cools and solidifies, it shapes the familiar cone-shaped mountains called volcanoes.
Image captured from the International Space Station showcasing the eruption of Mount Cleveland volcano in Alaska’s Aleutian Islands, USA
Each volcano behaves uniquely. Some exhibit explosive eruptions, like Mount Pinatubo, Philippines in 1991, while others, like Hawaii’s Kilauea volcano in 2018, release slow-moving rivers of lava in effusive eruptions. These behaviors stem from the magma’s chemistry. Magma with a runny consistency, or low viscosity, usually leads to effusive eruptions as gas escapes easily, letting the magma flow along the slopes. In contrast, explosive eruptions occur when thicker, viscous magma traps gasses, accumulating pressure until it releases abruptly.
Hawaii’s Kilauea Volcano eruption
Volcanoes exist on every continent, including Antarctica. Approximately 1,500 volcanoes worldwide are currently deemed potentially active, with 500 having erupted over the last century.
The “ring of fire” is home to 75 percent of the world’s active volcanoes. This 25,000-mile (40,000-kilometer) horseshoe-shaped region extends from South America’s southern tip, spans the West Coast of North America, runs through the Bering Sea, continues to Japan, and reaches New Zealand. Here, the Pacific and Nazca tectonic plates meet other plates.
The Ring of Fire, with trenches marked with blue lines
However, it’s crucial to note that the ring’s volcanoes are not geologically interconnected. For instance, a volcanic eruption in Indonesia doesn’t relate to one in Alaska, nor could it trigger the notorious Yellowstone supervolcano.
Time-lapse video of Chile’s Calbuco volcano eruption
The 1815 eruption of Mount Tambora in Indonesia stands as history’s deadliest. This formidable explosion formed a caldera—basically a crater—4 miles (6.4 kilometers) wide and over 3,600 feet (1,097 meters) deep. It propelled a superheated cloud of ash and gas 28 miles (45 kilometers) skyward, resulting in multiple pyroclastic flows upon collapse.
Panorama of the caldera of Mount Tambora, July 2017
This eruption directly claimed about 10,000 lives. However, its broader effects were even more devastating. The released ash and gas shielded the sun and heightened Earth’s reflectivity. This led to a significant drop in global temperatures, famously termed “the year without a summer.” Consequently, the resulting famine and disease claimed approximately 82,000 additional lives.
TL;DR
Volcanoes, responsible for shaping over 80% of Earth’s surface, originate from magma rising from the planet’s depths. Their behaviors vary, from explosive eruptions, like Mount Pinatubo in 1991, to effusive lava flows, like Hawaii’s Kilauea in 2018. Worldwide, 1,500 volcanoes are deemed active, with 500 erupting in the past century. Most lie within the 25,000-mile “Ring of Fire” where major tectonic plates meet. The 1815 eruption of Mount Tambora in Indonesia, the deadliest recorded, caused a massive drop in temperatures known as “the year without a summer,” leading to widespread famine and disease, killing nearly 92,000 people.
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Words of wisdom
“The mind is not a vessel to be filled, but a fire to be kindled.” —Plutarch
“No one asks how to motivate a baby. A baby naturally explores everything it can get at, unless restraining forces have already been at work. And this tendency doesn’t die out, it’s wiped out.” —B.F. Skinner
“We’re all going to die, all of us, what a circus! That alone should make us love each other but it doesn’t. We are terrorized and flattened by trivialities, we are eaten up by nothing.” —Charles Bukowski
“I would never die for my beliefs because I might be wrong.” —Bertrand Russell
Bibliography
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