SCIENCE

It’s not exactly the sudden explosion that many Americans imagine when they hear the words volcanic eruption. But for exactly that reason, “it’s the kind of eruption that makes volcanologists nervous.” (The Atlantic)

Use our activity to help students investigate how Kilauea’s erupts.

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

 

Discussion Ideas

• The great big Kilauea volcano is erupting with lava, volcanic gas, and volcanic ash. Where is Kilauea?
  • Kilauea is one of the five volcanoes that make up the “Big Island” of Hawaii. Three are active, two are dormant.
    • active. Kilauea, Mauna Loa, and Hualalai, on the southern part of the island, are all active volcanoes. Kilauea is the youngest and most active volcano, and has been erupting continuously since 1983. Mauna Loa last erupted in 1984. Hualalai last erupted in 1801.
    • dormant. Mauna Kea and Kohala, to the island’s north, are dormant volcanoes. Measured from its seafloor base, Mauna Kea is the tallest mountain on Earth. It last erupted about 5,000 years ago. Kohala is the oldest volcano on the Big Island, and last erupted more than 100,000 years ago.

 

 

• Kilauea and the rest of Hawaii’s active volcanoes sit over a hot spot. What makes hot spot volcanism unique? Skim our reference resource on hot spots for some help.
  • Hot spot volcanism is unique because it does not occur at the boundaries of Earth’s tectonic plates, where all other volcanism occurs. Instead, hot spot volcanism occurs at abnormally hot centers known as mantle plumes. Scientific models depict these plumes of molten rock almost like a lava lamp, with a rising bulbous head fed by a long, narrow tail that originates in the mantle.
    • Other hot spots likely include the Yellowstone hot spot (North American plate) and the Galapagos hot spot (Nazca plate).
    • While a hot spot remains relatively stable, the tectonic plate above it continues to move and shift due to its relationship with other plates and the rocky interactions in the mantle around it.
      • In this way, the Hawaiian Islands were created one right after the other as the mighty Pacific plate moved northwest, while the hot spot stayed put. The resulting Hawaiian-Emperor seamount chain stretches more than 5,800 kilometers (3,600 miles) across the North Pacific Ocean, from the 82-million-year old Meji Seamount near the Kamchatka Peninsula, to Loihi, the growing seamount to the southeast of the Big Island that will eventually become the next Hawaiian island. Learn more about Loihi, Kilauea, and Hawaii’s hot spot volcanism with our terrific video.

 

 

• What volcanic hazards are associated with the newest eruption of Kilauea? Take a look at this article from the good folks at the USGS for some help.
  • volcanic ash. Hours before Kilauea erupted with lava, it spewed a plume of pink ash hundreds of meters into the air. Wind can disperse ash dozens or even hundreds of meters across the island or ocean. Volcanic ash can make breathing difficult and can cause buildings and structures to collapse, damage agricultural crops, and contaminate grass used for livestock feed. The downwind ash plume from such eruptions also poses a hazard to aircraft.
    • Why was the plume pink? It rusted. The iron-rich minerals in Kilauea’s Pu’u O’o crater interact with oxygen in a process called oxidation, turning the ash pink.
  • volcanic gas. Among the gases emitted by erupting volcanoes are sulfur dioxide, which can be toxic to breathe and a corrosive on eye and skin contact. Sulfur dioxide, water vapor, carbon dioxide, and other components of volcanic gas are also major contributors to global warming, the current period of climate change.
  • fissures. Volcanic fissures are vents through which lava erupts, usually without explosive activity. Although Kilauea’s summit crater has experienced explosive eruptions, the most devastating aspect of the current activity is the series of 10 fissures that have opened on the volcano’s east flank.
  • fractures and subsidence. Moving magma, eruptions, the formation of fissures, and ground shaking from strong earthquakes produce an abundance of ground fractures and subsidence features that profoundly affect the landscape, human activity, and infrastructure such as roads and bridges.
  • earthquakes. Kilauea contributed to a magnitude 6.9 earthquake last week, followed by a series of magnitude 4-5 aftershocks. Such quakes can damage buildings, roads, bridges, and utilities. In Hawaii, damage can be intensified by water-saturated soils that amplify earthquake ground motions. On steep slopes, intense shaking may cause such soils to fail, resulting in landslides and mudflows.
  • lava flows. Lava flows destroy everything in their paths—rain forests, buildings, roads, utility and communication systems, and whole communities. The newest lava flows of Kilauea have already destroyed 26 homes in less than a week.
    • Lava entering the ocean presents its own set of hazards: Sudden collapse of a lava delta (new land created at ocean entry) and the adjacent sea cliff into the ocean, waves of scalding hot water, and steam plumes that can rain hydrochloric acid and tiny volcanic glass particles.

 

• All of that sounds terribly dangerous, and yet volcanologists say shield volcanoes like Kilauea are actually less dangerous than composite volcanoes. Why? Read through our activity to compare the eruption of Kilauea with the eruption of the composite volcano Vesuvius for some help.
  • Most shield volcanoes sit on oceanic plates. (Kilauea sits on the biggest oceanic plate of them all, the mighty Pacific.) Oceanic plates are largely composed of basaltic rocks. When basalt melts, it tends to form lava that is very fluid and runny. “This type of lava can get very hot, but it’s so liquid-like that any gas just bubbles out of it. ‘Hawaiian volcanoes can be extremely deadly, but it’s a hazard you can walk away from,’ says Mika McKinnon, a geophysicist and disaster researcher.
  • Most composite volcanoes sit on continental plates. (Vesuvius sits on the Eurasian plate.) Continental plates are largely composed of granite rocks. When granite melts, it is very sticky and slow-moving. Gas, instead of escaping into the atmosphere, gets trapped inside this kind of lava. Eruptions are much, much more explosive, contain much more ash, and result in much more toxic pyroclastic flows.

 

 

• If people can safely walk away from Kilauea’s lava domes and runny lava, why are the fissures and eruptions making volcanologists nervous?
  • displaced people. More than 1,700 residents have been evacuated from communities on Kilauea’s eastern flank. If the fissures keep oozing lava, the evacuations may be permanent. That’s a lot of environmental refugees.
    • “There’s not a lot of words to capture a gradual, slow-developing disaster like this. Even disaster doesn’t seem like the right word, because it implies something instantaneous or rapidly developing—and this isn’t. But it will still be quite a disaster for people whose homes are taken out,” says volcanologist Erik Klemetti.

 

TEACHERS TOOLKIT

The Atlantic: Why Hawaii’s Newest Eruption Makes Volcanologists Nervous

USGS: Volcano Hazards Program-Kilauea

USGS: Volcano Hazards Program-Hazards

Nat Geo: Types of Volcanic Eruptions

Nat Geo: What is a volcano?

Nat Geo: What is a hot spot?

Nat Geo: What is volcanic ash?

Nat Geo: What is magma?

Nat Geo: Hawaii Geology