Deep magma reservoirs, such as that below the Yellowstone caldera, are the key to causing volcanic ‘super-eruptions’, that could threaten millions of lives, new research suggests.
If a mega eruption of Yellowstone, one of the world’s largest super volcanoes, happened so much toxic ash and moult on rock would be hurled into the atmosphere it could block out sunlight and trigger a nuclear-winter type effect or even a mini ice age.
An international team of geologists carried out the study which shows the importance of large magma reservoirs in creating Earth’s most powerful volcanic eruptions.
The researchers claim that the most powerful volcanic eruptions, dubbed ‘super-eruptions’, are triggered by a slow and steady drip feed of magma from large reservoirs deep within the Earth’s crust into smaller reservoirs closer to the surface.
These large reservoirs draw in hot magma from the Earth’s mantle and exist as large volumes of partially molten rock that are able to store magma like a sponge.
By conducting a number of numerical simulations of this process, the research team showed that these large reservoirs are crucial to generating the largest volcanic eruptions on Earth.
But, fortunately, the team also showed that these large reservoirs can take millions of years to form, hence why ‘super-eruptions’ happen so rarely.
Yellowstone is believed to have seen super eruptions at intervals of two million, 1.2 million and 640,000 years ago, meaning another one could be due any time.
It is believed the new findings could help to understanding why some volcanoes erupt frequently and at certain magnitudes.
The study, published in the journal Nature Geoscience, found the amount of magma that is stored in the upper layer of the Earth’s crust determines the frequency and magnitude of volcanic eruptions.
Small eruptions that erupt less than one cubic kilometre of material occur very frequently (from daily to yearly), while the largest eruptions that erupt hundreds of cubic kilometres of material are infrequent, with hundreds of thousands of years between them.