Mauna Loa eruption: What's happening inside the world's biggest volcano?

Mauna Loa - the world's largest progressive volcano - is erupting for the archetypal clip since 1984.

Lava is flowing down the broadside of the volcano astatine a somesthesia of 1,000C, but experts accidental this does not yet airs a large menace to section inhabitants.

Mauna Loa, which means "long mountain" successful Hawaiian, is the largest progressive volcano successful the world.

It covers 2,035 sq miles (5,271 sq km), and is 1 of a concatenation of 5 volcanoes which signifier Hawaii's Big Island.

This 1 volcano unsocial comprises fractional of the full island.

Mauna Loa's acme is 13,680ft (4,170m) supra oversea level, but its basal is connected the oversea floor. From determination to the acme is 30,085ft (9,170m), making it taller than Mount Everest.

Plumes of super-heated worldly called magma person been welling up underneath Mauna Loa and neighbouring volcanoes from a "hotspot" heavy wrong the Earth.

"No 1 knows precisely wherefore this hotspot exists," says Dr Carmen Solana, a volcanologist astatine Portsmouth University, "but it whitethorn beryllium caused by the decay of radioactive worldly wrong the Earth's mantle.

"These plumes of magma formed the full of the Hawaiian Islands."

When Mauna Loa erupted, says Dr Solana, magma archetypal welled up successful the caldera - the bowl-shaped pit astatine the acme of the volcano. Called Mokuaweoweo, it covers an country of six sq miles (15 sq km) and is 600 ft (180m) deep.

Magma past comes retired successful fountains from "rifts", oregon fissures successful the rock, connected the broadside of the volcano. Some of these fountains are 40m high.

It flows down the mountainside arsenic liquid lava, which has a somesthesia of 1,000C.

Lava is besides propelled into the air, immoderate of which stretches into bladed strands of solid called Pele's hair.

"Pele was the sanction of the goddess who was said to unrecorded connected Hawaii, and the shards are wispy and browny-gold successful colour," says Dr Solana.

Mauna Loa has erupted 33 times since 1843, the day of the archetypal recorded eruption. On average, that it is 1 eruption each 5 and a fractional years.

However, the past eruption was astir 40 years ago.

"There person been immoderate signs of magma welling up implicit the past 10 years," says Andrew Hooper, a prof of geophysics astatine Leeds University successful the UK, "but determination has been nary eruption until now."

The existent eruption connected Mauna Loa is giving a caller procreation of scientists the accidental to survey however the volcano works, says Professor Hooper.

"It volition beryllium absorbing for america to spot wherever the magma is stored wrong Mauna Loa - wherever it stays successful betwixt welling up from the Earth's mantle and coming retired from the volcano's surface," helium says.

Unlike galore volcanoes, Mauna Loa usually does not nutrient truly explosive eruptions, successful which plumes of ash and state sprout precocious into the air.

Instead, the lava flows astatine a reasonably dilatory gait down the volcano's side.

"The lava flows are not beingness threatening," says Professor Hooper, "because you tin get retired of the mode of them."

"Also, the lava is not going westbound down the volcano towards the closest towns, but to the north-east. It would person to question rather a agelong mode successful that absorption earlier doing superior harm to property."

However, section radical whitethorn beryllium much astatine hazard from the gases which Mauna Loa is emitting.

"Volcanic gases, including sulphur dioxide... respond with moisture successful the aerial to nutrient 'vog', which is volcanic fog," says Dr Solana.

"This could origin a occupation to radical downwind. It could irritate the eyes, and origin breathing problems for immoderate people."

If it does, section residents are advised to debar outdoor activities and to enactment indoors with doors and windows shut.