Ranking right up there in the Things People Worry About is the potential for a cataclysmic super-eruption of the Yellowstone hotspot. According to a new study, however, the volcanic region may currently be waning.
For those who are unfamiliar with it, the Yellowstone hotspot is an area of volcanic activity located beneath the Yellowstone Caldera in the US states of Wyoming, Montana and Idaho.
Geological evidence indicates that over the past several million years, it has experienced multiple huge eruptions, known as super-eruptions. There are worries that it may soon be due for another, which could result in massive fatalities and long-lasting environmental destruction.
That said, there may be new hope, as a recent international study suggests that the hotspot could currently be in a state of decline. This finding was based on an analysis of volcanic deposits that were scattered across tens of thousands of kilometers in the region.
"We discovered that deposits previously believed to belong to multiple, smaller eruptions were in fact colossal sheets of volcanic material from two previously unknown super-eruptions at about 9.0 and 8.7 million years ago," says Thomas Knott, a volcanologist at Britain's University of Leicester. "The younger of the two, the Grey’s Landing super-eruption, is now the largest recorded event of the entire Snake-River-Yellowstone volcanic province. It is one of the top five eruptions of all time."
The two super-eruptions took place during the Miocene geological era, a time period spanning 23 to 5.3 million years ago. Their discovery brings the total of Miocene super-eruptions for the region up to six, suggesting that the area experienced such eruptions an average of once every 500,000 years.
By contrast, over the past 3 million years, the Yellowstone hotspot has seen just two super-eruptions. This may indicate that the frequency of such events is slowing considerably.
"We have demonstrated that the recurrence rate of Yellowstone super-eruptions appears to be once every 1.5 million years," says Knott. "The last super-eruption there was 630,000 years ago, suggesting we may have up to 900,000 years before another eruption of this scale occurs."
He is quick to add, however, that the 900,000-year figure is just an estimate, and that the region should continue to be frequently monitored by the US Geological Survey.
A paper on the research, which also included scientists from the University of California Santa Cruz, was recently published in the journal Geology.
