Science

Kilaueas spectacular pyrotechnics show no signs of stopping

July 4th fireworks have nothing on Kilauea.

As the Hawaiian volcanos latest outburst enters its third month, scientists are still watching Kilauea 24/7. Such constant monitoring not only provides danger warnings aimed at keeping those nearby safe, but it also offers remote viewers the rare opportunity to observe the evolution of an eruption in real time.

As magma within Kilaueas summit crater, called Halemaumau, continues to drain and move toward the lower east rift zone, the crater floor is becoming increasingly unstable. The U.S. Geological Service has observed frequent rockfalls into the crater since mid-May; each collapse triggers a small explosion. One of the largest explosions happened June 30, when a collapse-explosion cycle released energy equivalent to a magnitude 5.3 earthquake.

While a “Whomp!” and a slow-rising cloud of volcanic gas and ash marked that collapse, the real pyrotechnics are happening along nearly two dozen fissures, vents through which lava erupts, in that lower east rift zone. Lava fountains spurting from two fissures, Nos. 8 and 22, are feeding most of the lava flows now pouring into the ocean.

Its hard not to stare slack-jawed at images of molten rock spurting into the air, of glowing, fast-moving rivers of lava rushing into the ocean, or of the tangles of wispy-sharp shards of glass known as Peles hair. Check out these highlights of Kilaueas show and the science (and volcanic vocabulary) were learning from them.

Hot vortex

Of nearly two dozen fissures, No. 8 at the eastern edge of the now devastated Leilani Estates neighborhood is producing some of the most spectacular pyrotechnics, including this lava whirlwind, or lavanado. Lavanadoes form much like “firenadoes” do from the wrath of wildfires: Intense heat (in this case, from the volcano itself) causes air to swiftly rise and form a tall column, and strong winds can then cause the column to rotate. Here, the lavanado dances with the molten rock before flinging the lava several meters away.

A whirlwind partly made of hot lava swirls above one of Kilaueas active fissures.

In the vog

A thick fog curls out of fissures and seeps along the ground. Dubbed vog, this volcanic smog forms as sulfur dioxide and other gases and particles seeping out from the fissures react with oxygen, water vapor and sunlight. Since Kilauea began erupting along its lower east rift zone, within Leilani Estates, scientists warned anyone in the vicinity to wear protective masks due to emissions of this toxic air pollution.

Ropy rock

The kind of lava erupting from Hawaiian volcanoes, a molten basalt rock, cools into two main types of formation. When the lava flows slowly, air cools its “skin”— but beneath that skin, the lava continues to ooze ahead, advancing toe by toe. The smooth, ropy skin and toe-shaped lobes are characteristic of pahoehoe lava.

By contrast, more swiftly flowing lava, known as Aa, appears chunky and angular. Thats because faster-moving lava loses heat more quickly and becomes more resistant to flow. Instead of a slow, sinuous advance, the lava tears ahead, forming large, hardened chunks.

Fast flow

Glowing torrents of lava fed by fissure 8 on Kilaueas lower east rift zone jet through a channel at speeds of about 7.7 meters per second. USGS scientists shot this video June 19, but the rivers continue to flow.

A glowing river of lava, from fissure 8 on Kilaueas lower east rift zone, races to the ocean.

Much like a river of water, flow is fastest at the center of the river and slowest along the edges of the lava channel due to friction. Lava waves form as the molten rock sloshes through lava rapids, along its 13-kilometer journey before it spills into the ocean.

On a boat

Also like many water rivers, the lava rivers have occasional passengers. Lava boats are rafts made of pieces of hardened lava that clump together and get carried downstream, like boats on a waterway.

A huge chunk of lava, dubbed a lava boat, sails away on this river of lava as Kilauea erupts.

As the lava boats travel, more pieces of lava may cool and glom onto their surface, forming accretions called lava balls.

Toxic steam

As Kilaueas rivers of fire pour into the ocean, they boil the water, sending great clouds of corrosive steam billowing into the air. The steam is a concoction that volcanologists call laze, or lava haze, and its the product of a chemical reaction between the hot lava and seawater.

The lava, at a temperature of about 1150° Celsius, basically boils away the seawater, leaving behind very reactive sea salts, such as magnesium chloride. These salts react with the steam to form hydrochloric acid. Similar in strength to weak battery acid, laze can irritate eyes and skin, and cause breathing difficulties.

Glass hair

When tiny droplets of lava spray into the air and rapidly cool, they can form fine threads of volcanic glass. Dubbed Peles hair, they are named for the Hawaiian goddess of fire and volcanoes.

The fibers are so fine that they can be carried along by the wind before raining out. But its not a gentle rain: The sharp threads are abrasive enough to scratch car windshields and can irritate skin and eyes, or contaminate open water reservoirs.

The new lava delta filling in what was once Kapoho Bay now spans more than 162 hectares, USGS scientists say, the equivalent of more than 300 U.S. football fields. And with the eruption – and Kilaueas pyrotechnics – showing no signs of slowing (SN Online: 5/8/18), the Big Island will probably continue to grow.

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