Hottest thing on earth? Oozing melted rock

Posted6/13/2018 1:00 AM
  • Lava from the Kilauea volcano erupts from a fissure and forms a river of lava flowing down to Kapoho on Sunday, June 10, 2018, in Pahoa, Hawaii.

    Lava from the Kilauea volcano erupts from a fissure and forms a river of lava flowing down to Kapoho on Sunday, June 10, 2018, in Pahoa, Hawaii. (AP Photo/L.E. Baskow)

  • Mount Redoubt with Mount Iliamna in the background, two of 90 volcanoes in Alaska.

    Mount Redoubt with Mount Iliamna in the background, two of 90 volcanoes in Alaska. Courtesy of AVO/USGS, Gabrielle Tepp

"What is the hottest thing on Earth?," asked a young patron attending the Write Away program at Vernon Area Public Library in Lincolnshire.

Oozing melted rock that pulses from deep inside the earth can top temperatures of 2,300 degrees Fahrenheit.

In the past weeks, the Hawaii Volcano Observatory has sent daily news alerts on fissure openings, flows, splatters and steam vents surrounding the Kilauea Volcano eruptions on the Big Island of Hawaii. Using thermal mapping, scientists tracked the volcano's emissions with temperatures upward of 1,179 degrees Fahrenheit.

Lava is the hottest natural thing on Earth. It comes from the Earth's mantle or crust. The layer closer to the surface is mostly liquid, spiking to an astounding 12,000 degrees and occasionally seeping out to create lava flows. Closer to the core, the rock is solid, explained Sonja Melander, science education coordinator at the Mount St. Helen's Institute.

"The inside layers of the earth, except for the outer core, which is made of liquid iron and nickel, are not made of liquid rock due to the tremendous amount of pressure they are under," Melander said.

The not-for-profit Institute is situated near the Cascades Volcano Observatory and offers youth and adult educational programming covering the Mount St. Helen's volcano. A devastating blast in 1980 caused 57 deaths, flattened the mountaintop, destroyed thousands of acres of forest and catapulted ash in a 300-mile radius. In only a few years, life re-emerged from the scorched surroundings.

The hot magma that emerges as lava can cause earthquakes, such as at the recent Kilauea eruption, which logged a 6.9 magnitude earthquake. The position of the Hawaii volcanoes on top of a sensitive hot spot makes them volatile. By contrast, Mount St. Helen's, where Melander works, is a volcano that became active when tectonic plates collided.

Kilauea, Mount St. Helen's and the more than 100 volcanoes in Alaska are part of a string of volcanoes that sit along the Ring of Fire. It branches from Peru and South America, bows up to Hawaii, then north through Washington State and along the coast to Alaska, bends east along the Aleutian Islands to Japan, then south through the Philippines, ending at the island of Tonga. The arc is peppered with nearly 500 underwater and aboveground volcanoes.

Gabrielle Tepp, Mendenhall Fellow and Research Physical Scientist at the Alaska Volcanoes Observatory, compares the sheer number of active volcanoes in Alaska to the more well-known erupters in Hawaii.

"There are four volcanoes in Hawaii that could potentially have an eruption. Of those, three have erupted since 1800 and are considered active. There is also an active underwater volcano east of Hawaii that erupted in 1996," Tepp said. "In comparison, Alaska is home to about 90 volcanoes that are thought to be capable of erupting. Most of them are located in the Aleutian Islands and on the Alaska Peninsula. Fortunately, most of the Alaskan volcanoes are remote, so very few people live on or near them, unlike the volcanoes that make up the Island of Hawaii."

Lava is extremely hot, and scientists have figured out how to record those fiery temperatures. Volcanologists, scientists who specialize in volcanoes, use specially designed tools to measure the very high temperatures as eruptions are occurring.

"Temperature can be measured by thermocouples, which are essentially special probes volcanologists can poke lava with," Melander said. "They are made of wires with two different metals surrounded by ceramic and stainless steel, which have a higher melting point than the lava. When the lava is poked with the thermocouple, the electronic current in the device changes, which determines temperature."

Special photography captures heat emanating from hard-to-reach volcanoes. Melander said infrared radiation can gauge temperature.

"In remote locations, volcanoes can be watched by looking at infrared pictures taken from satellites," Melander said.

Magma can be put to good use. In Iceland, magma was harnessed to generate geothermal energy, enough to power 36,000 homes.

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