University of Leicester

Supervolcano ‘even more colossal’

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Yellowstone hot spring
Hot springs are surface evidence of the huge magma chamber that sits beneath Yellowstone

The supervolcano that lies beneath Yellowstone National Park in the US is far larger than was previously thought, scientists report.

A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.

A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.

The findings are being presented at the American Geophysical Union Fall Meeting in San Francisco.

Prof Bob Smith, from the University of Utah, said: “We’ve been working there for a long time, and we’ve always thought it would be bigger… but this finding is astounding.”

If the Yellowstone supervolcano were to blow today, the consequences would be catastrophic.

The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.

Now researchers believe they have a better idea of what lies beneath the ground.

The team used a network of seismometers that were situated around the park to map the magma chamber.

Dr Jamie Farrell, from the University of Utah, explained: “We record earthquakes in and around Yellowstone, and we measure the seismic waves as they travel through the ground.

“The waves travel slower through hot and partially molten material… with this, we can measure what’s beneath.”

Yellowstone ash plume It is unclear when the Yellowstone supervolcano will erupt again

The team found that the magma chamber was colossal. Reaching depths of between 2km and 15km (1 to 9 miles), the cavern was about 90km (55 miles) long and 30km (20 miles) wide.

It pushed further into the north east of the park than other studies had previously shown, holding a mixture of solid and molten rock.

“To our knowledge there has been nothing mapped of that size before,” added Dr Farrell.

The researchers are using the findings to better assess the threat that the volatile giant poses.

“Yes, it is a much larger system… but I don’t think it makes the Yellowstone hazard greater,” explained Prof Bob Smith.

“But what it does tell us is more about the area to the north east of the caldera.”

He added that researchers were unsure when the supervolcano would blow again.

Some believe a massive eruption is overdue, estimating that Yellowstone’s volcano goes off every 700,000 years or so.

Bison The National Park is a biodiversity hotspot in the continental United States

But Prof Smith said more data was needed, because there had only been three major eruptions so far. These happened 2.1 million years ago, 1.3 million years ago and 640,000 years ago.

“You can only use the time between eruptions (to work out the frequency), so in a sense you only have two numbers to get to that 700,000 year figure,” he explained.

“How many people would buy something on the stock market on two days of stock data.”

In another study presented at the AGU Fall Meeting, researchers have been looking at other, more ancient volcanic eruptions that happened along the same stretch of continental plate that Yellowstone’s supervolcano sits on.

Dr Marc Reichow, from the University of Leicester, said: “We looked at a time window of between 12.5 to 8 million years ago. We wanted to know how to identify these eruptions and find out how frequently they happened.”

The team found there were fewer volcanic events during this period than had been estimated, but these eruptions were far larger than was previously thought.

Dr Reichow added: “If you look at older volcanoes, it helps to understand what Yellowstone is likely to do.”

Grandparents ‘may relay autism risk to grandchildren’.

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The risk of developing autism may be passed on through – and not just to – future generations, researchers say.

The international study suggests older fathers are more likely to have grandchildren with autism than their younger counterparts.

The mechanism is unclear but it is thought they may transmit “silent mutations” to their grandchildren.

But experts have urged caution, stressing autism is the result of many different factors.

The study, looking at almost 6,000 people with the condition, is published in the journal Jama Psychiatry.

According to the National Autistic Society, more than one in every 100 people in the UK have the condition.

Previous studies suggested older fathers may be at greater risk of having children with autism than younger dads.

But the team of UK, Swedish and Australian researchers say this is one of the first pieces of evidence to show the risk can be passed on through – rather than just straight to – future generations.

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We can’t put exact figures on this risk yet. But most children born to older fathers and grandfathers grow up fine”

Dr Avi ReichenbergCo-author of study

The “silent mutations” – changes in genetic material – are likely to have no obvious impact on older fathers’ own children, but they may build up through subsequent generations, or interact with other genes and environmental factors, to increase the chance of their grandchildren developing the condition, the researchers say.

Using national databases from Sweden they studied almost 6,000 people diagnosed with the condition and more than 30,000 without, tracking their parents’ and grandparents’ ages.

They found men who had a daughter when aged 50 or older were 1.79 times more likely to have a grandchild with autism, compared to men who fathered children when aged between 20-24.

And those who had a son when 50 years of age or older were 1.67 times more likely to have a grandchild with the condition.

‘Complex causes’

But they say this study should not discourage older people from having children as though the risk is increased, it still remains small.

Co-author of the study, Dr Avi Reichenberg from King’s College Institute of Psychiatry, told the BBC: “It is about choices. If you choose to have a child at an old age there might be consequences. This is something everyone should consider.

Autism

 

  • People with autism usually have difficulties with social communication, social interaction and social imagination
  • It is a spectrum condition meaning while all people with autism share certain difficulties, the condition affects them differently
  • There are more than 500,000 people with autism in the UK – that’s one in every 100
  • There is no cure, but there are a range of interventions available

Source: NHS Choices

“Unfortunately we can’t put exact figures on this risk yet. But most children born with older fathers and grandfathers grow up fine.

“And as scientists this type of information helps open doors to understanding more about the condition.”

Caroline Hattersley, of The National Autistic Society, said: “While this research is useful in aiding our understanding of autism’s complex causes, it should be treated with caution.

“Autism is thought to be the result of many different underlying physical and genetic factors.

“The study is not definitive, as we know that many people who had children at a young age also have grandchildren with the condition. We therefore urge parents and those thinking of starting a family not to be concerned about the findings.”

Dr Terry Brugha, professor of psychiatry at the University of Leicester who was not involved in the study, said: “This is a solid piece of work and the findings are plausible. But as a grandparent or parent-to-be this is not something to be overly concerned about.

“We are at the early stages of research and this study gives us a slightly deeper understanding of what is going on in the background.”

Source:BBC