Lava Lakes, Lava Flows, Lava Domes

Maria J. Danford

Lava is amazing. Molten rock that erupts onto the surface area at 1000’s of degrees! Our mainly reliable planet (preserve for the liquid outer main, but that metal, not lava) can melt but all that molten substance just isn’t the exact same. All those discrepancies in composition are what drives the unique actions of lava on the surface area.

There is a (generally) easy relationship in between lava composition and actions. The much more silica (SiO2) in the lava, the “stickier” it is. This raise in viscosity implies that lava goes from absolutely free-flowing to scarcely-flowing. Different volcanoes will erupt unique compositions of lava based on how the rock melts at the volcano and how it changes as it would make its way to the surface area.

The composition just isn’t the only aspect that changes the lava’s stickiness. The hotter the lava, the runnier it is. Extra crystals in the lava? Stickier. Extra h2o dissolved in the lava? Runnier. Extra bubbles forming? Stickier. The closing viscosity of the lava is a difficult mix of all these aspects, but composition seriously drives the bus.

Appropriate now, we have 3 impressive eruptions going on across the world that seriously demonstrate off the kinds of lava eruptions. In Hawai’i, Kīlauea has a new lava lake at its summit Halema’uma’u Crater. On Sicily, Etna has been erupting very long, snaking lava flows. At the exact same time, La Soufrière on St. Vincent has a squat lava dome forming.

Kīlauea’s Lava Lake

Kilauea Lava Lake

The surface area of the Kilauea Lava Lake witnessed on January 10, 2021. The cooler, hardened surface area can be witnessed on the right. Credit history: Rob Simmon, Planet.

Since late 2020, Kīlauea has burst back to lifestyle immediately after over two several years of peaceful. The summit eruption has started out to fill the deep crater that shaped during the 2018 Lessen East Rift Zone activities. In the approach, a new lava lake (earlier mentioned) as set up alone at the summit and it is getting fed by a vent on the side of the lake. After about a thirty day period of eruption, the lake is now over 650 feet (200 meters) deep!

In this animated GIF (beneath) of the filling of the lava, you can see how fluid it is as a floating island of cooled lava moved close to its surface area. You can also see how the surface area behinds like a layer of “plates” of lava that are made and wrecked — a little bit like a mini edition of plate tectonics. The vent feeding the lava lake is in close proximity to the base of the picture.

Kilauea Lava Lake

Animated GIF of thermal photos from the new Kilauea lava lake. Credit history: USGS/HVO.

Lava lakes involve low silica lava known as basalt. Now, by “low silica”, we are however talking 47% of the lava is made of silica together with things like iron, magnesium, calcium and numerous other people. This basalt has close to the lowest viscosity and highest temperature of any lava erupting on Earth today and that makes it possible for for a lava lake to form as together as new lava is repeatedly fed.

Etna’s Lava Flows

Etna from Space

The lava flows (right side of summit) from Etna witnessed by Sentinel-two on January 19, 2021. Credit history: ESA.

On the other side of the world, Etna on Sicily has been erupting vigorously so significantly this 12 months. The eruptions have produced explosions at the summit as properly as lava flows that have headed down the eastern slopes. The eruption has also unfold ash on the slopes of the volcano.

Lava Flows from Etna

Thermal picture of the lava flows from Etna in Italy on January 21, 2021. The lava flows demonstrate up as shiny in this picture. Credit history: INGV Osservatorio Etneo.

The basaltic andesite lava erupting at Etna is rather much more silica abundant than Kīlauea’s. This implies it is stickier and tends to create Strombolian eruptions. These eruptions have explosions brought about by massive bubbles of fuel soaring by way of the pipe that leads from the supply of the lava below the volcano to the surface area. The lava is however runny more than enough to form lava flows from the vent as properly and that is what is going on at Etna right now. The infrared picture from Sentinel-two reveals the energetic flows coming down from the Southeast Crater.

La Soufrière’s Lava Dome

At last, we get to lava domes. These are shaped by even stickier lava that erupts like squeezing toothpaste out of a tube. The lava does get significantly and rather just “piles up” generating a thick dome. Volcanoes like La Soufrière on St. Vincent erupt andesite (not to be bewildered with the beforehand pointed out basaltic andesite) that might have up to 65% silica. This would make it considerably stickier than the lava erupting at Etna or Kīlauea.

La Soufriere Dome

The 2020-2021 lava dome at La Soufrière on St. Vincent in the foreground, with the 1979 dome in the history. Credit history: College of West Indies Seismic Investigate Centre.

The new lava dome forming at La Soufrière is over 1,100 feet (380 meters) across and 300 feet (90 meters) thick. It started out forming at the quite stop of 2020 and it was the first eruption at La Soufrière considering the fact that 1979. Test out this video of a helicopter flight over the increasing lava dome.

The domes steep sides and extreme thickness appears extraordinary for andesite lava erupting when compared to the basalt lava of Kīlauea. On the other hand, the viscosity of lava goes up quickly when much more silica is included. The lava in the Soufriére dome might be up 1000’s of situations stickier than the Hawaiian basalt. If you assess the significantly finishes of the lava compositional spectrum — basalt and rhyolite — you discover that rhyolite is a billion situations much more viscous! Some rhyolite lava domes and coulees (type of like a hybrid of a dome and stream) can be hundreds of feet thick.

Most eruptions of lava to form these attributes are somewhat passive. When you are considering about volcanic dangers, lava flows are poor for buildings and infrastructure but not folks. All of this difference in stickiness is what drives the unique varieties of lava lakes, flows and domes.

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