Hawaii’s Kilauea volcano erupts with a circulate of syrupy lava, serving as a vivid reminder of nature’s harmful energy. However as the continued eruption makes headlines, you’ll have a query: What’s the distinction between magma and lava?
The distinction between magma and lava is about location. When geologists discuss with magma, they’re speaking about molten rock that’s nonetheless trapped underground. If this molten rock involves the floor and flows like a liquid, then it’s known as lava.
Magmas differ of their chemical composition, which provides them – and the volcanoes they comprise – totally different properties.
Mafic magmas like these in Hawaii type when the heavy crust that makes up the ocean flooring melts. They comprise 47 to 63 p.c silica, the mineral that makes up glass and quartz. So far as molten rocks are involved, mafic magma is kind of flowing, with viscosity starting from molasses to peanut butter. They’re additionally the most well liked number of magma, reaching temperatures between 1,800 levels and a pair of,200 levels Fahrenheit.
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Silicic magmas, alternatively, are shaped by the melting of lighter continental crust. These magmas are greater than 63 p.c silica, which makes them extra viscous: at their quickest, silicic magma flows in addition to lard or caulk – which isn’t superb in any respect. They’re even higher than mafic magma. Rhyolite, a very silica-rich sort of lava, solely hits temperatures between 1,200 levels and 1,500 levels Fahrenheit.
Why achieve this many individuals dwell close to lively volcanoes?
Since silicic magmas are colder and guppier than mafic magmas, dissolved gases have a more durable time shifting out of them. This makes silicic magma extra harmful: as extra fuel builds up within the magma, it turns into extra explosive, like including increasingly carbonation to soda.
When silicic magmas are now not confined underneath sufficiently excessive strain, the dissolved gases inside them precipitate out of resolution and type bubbles. And as quickly as you open a shaken can of soda, the ensuing rush of vapor triggers an explosive explosion. Iconic cone-shaped volcanoes known as stratovolcanoes, resembling Mount Pinatubo, are stuffed with silicic magma.
Hawaii’s volcanoes, alternatively, comprise solely low-silica magma composed of basalt, which suggests they’ve little or no explosive oomph. As an alternative, they erupt and erupt, creating protect volcanoes – the gently sloping formations which have turn into the islands’ signature geologic silhouette.