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Deadliest Volcanoes

From Japan&#x27;s Mt. Fuji to Yellowstone&#x27;s buried supervolcano, how can we best prepare for the most lethal eruptions?

Meet the Volcanoes

<div class="rich-text">Volcanoes can come in many shapes and sizes.</div>
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	In big blockbuster films, all volcanoes look the same: they are huge pointed peaks that violently erupt, destroying everything in their path. While some volcanoes do look like their Hollywood stand-ins, many others do not. In fact, they vary in size, lifespan, and even in the way they erupt.
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<div class="rich-text"><h3>
 Meet the Volcanoes
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 Posted: January 3, 2013


 
 Narrator:
 
 You probably have a pretty good idea what this is. It’s a volcano—a place where molten rock, called magma, from deep within the Earth, makes its way up and erupts at the surface. But what you may not know is that not all volcanoes are made in exactly the same way. In fact, they come in a variety of different shapes and sizes. Here are the three main types of volcanoes.


 The smallest type of volcano is the cinder cone. Cinder cones form when thin or runny magma is flung in the air during an eruption, and then hardens and falls back to earth in fragments called “cinders.” Over time, these cinders build up, creating a cone shaped mound. Cinder cones can form rapidly, and are the shortest-lived volcanoes. A famous one is the Parícutin volcano, which formed in a Mexican cornfield in 1943. It was active for only nine years, but in that time it transformed what was once farmland into a 1,200-foot high peak, destroying two villages in the process.


 The largest type of volcano is the shield volcano. These volcanoes pour out very runny lava flows, which can travel many miles. When the flows cool, they form thin sheets. These sheets build up to form a wide dome that resembles a warrior’s shield. Despite their size, they’re actually the gentlest volcanoes. In fact, tourists can actually watch the slow flow of lava from the shield volcanoes that form the Hawaiian Islands.


 The most common type of volcano is the composite, or stratovolcano. These are what most people think of when they imagine volcanoes. They usually come in groups of volcanoes all aligned in a chain. They’re formed from alternating lava flows, and layers of hardened particles called tephra that are flung out of the volcano during an eruption. Composite volcanoes have the most violent eruptions, because the lava they eject is stickier, or more viscous, than the lava from cinder cones or shield volcanoes. As a result, more pressure builds up in the volcano before an eruption.


 Some composite volcanoes have what is known as a “lava dome” grown on the top, often within the volcanic crater. These form when thick, very viscous lava gets pushed up over the vent like toothpaste and hardens, creating a sort of lid on the volcano. Volcanoes with lava domes have very forceful eruptions, because the magma has to push its way through the lid. Mt. St. Helens famously grew a lava dome in the crater that formed during the 1980 eruption.


 These are the three main types of volcanoes, but there’s plenty more explosive science to discover.
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<div class="rich-text">Volcanoes can come in many shapes and sizes.</div>

Killer Volcanoes

Scientists hunt for a mega-eruption that plunged medieval Earth into a deep freeze.

Doomsday Volcanoes

Could the explosion of Iceland&#x27;s ticking time bombs cause cold and famine worldwide?

Tale of Two Volcanoes

<div class="rich-text">Hawaii’s Kilauea and Guatemala’s Fuego volcanic eruptions have been remarkably destructive.</div>
<div class="rich-text">Two powerful volcanoes erupted in the same week, one in Guatemala, the other in Hawaii. The eruptions were not connected, and the devastation was&nbsp;entirely different. In Guatemala, a&nbsp;fast-moving pyroclastic flow engulfed the residents of a nearby village, killing more than a hundred people, and&nbsp;leaving a scene reminiscent of Pompeii. Meanwhile, in Hawaii, Kilauea&rsquo;s slow-moving lava rivers have devastated&nbsp;hundreds of homes, although fortunately, they have not yet caused any deaths.
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<div class="rich-text"><h3>
 Tale of Two Volcanoes
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 Published June 14, 2018


 
 Onscreen:
 
 Two volcanoes just erupted with destructive power. Guatemala’s Volcán de Fuego and Hawaii’s Kilauea. The eruptions aren’t connected, and hazards are different


 At Fuego, hot volcanic ash and mud engulfed a nearby village. At least 75 people died, over 3,000 evacuated. And the death toll is expected to climb


 
 John Stix:
 
 EI Fuego is known for its pyroclastic flows.


 
 Onscreen:
 
 Pyroclastic flows are not lava.


 
 Stix:
 
 They’re very similar to snow avalanches. They move very fast, just like a snow avalanche does.


 
 Onscreen:
 
 Except pyroclastic particles consist of volcanic ash and rock, tumbling down a volcano at hundreds of miles per hour


 
 Stix:
 
 Anybody, or anything in the path of a pyroclastic flow, once it’s started, you don’t really have the time to get out of the way of it. So they will burn and asphyxiate anybody in their path. It’s a small-scale Pompeii, in a sense.


 
 Onscreen:
 
 The rainy season just started in Guatemala, increasing the risk of mudflows called lahars.


 
 Stix:
 
 Loose ash will mix with the rain and create mudflows that will impact a lot of people.


 
 Onscreen:
 
 They can travel farther than pyroclastic flows.


 
 Stix:
 
 They can move faster than you can run.


 
 Onscreen:
 
 Meanwhile, new explosions at Kilauea rocked the summit, sending ash thousands of feet into the air. And a new massive river of lava is believed to have destroyed nearly 300 homes.


 
 Stix:
 
 A lava flow is a slow-moving liquid which is highly viscous, not moving very fast...these lava flows have been moving slowly—people can get out of the way.


 
 Onscreen:
 
 So far, Kilauea’s recent activity has caused no deaths. But there may be more hazards to come.


 
 USGS Jessica Ballx:
 
 There is now a flow that has channelized south of the new delta.


 
 Onscreen:
 
 Stirring up a laze: a dangerous mix of lava and haze. Residents continue to keep an eye on both volcanoes.

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<div class="rich-text">Hawaii’s Kilauea and Guatemala’s Fuego volcanic eruptions have been remarkably destructive.</div>

Protecting People from a Hidden Hazard of Volcanoes

Learn how scientists are trying to protect people living in the Democratic Republic of Congo from the dangers of this and other harmful gases found in high concentrations both on land and underwater throughout the region in these videos from NOVA: Volcano on Fire and Volcano on the Brink.

Using Waves to Study Volcanoes

Learn how scientists use seismic waves and sound waves to study volcanoes and forecast their behavior in these videos from NOVA The Next Pompeii.