Scientists detect warning signs in quartz crystals.
The worst explosion on Earth in historic times was the eruption of a volcano in Indonesia called Mount Tambora in 1815. It killed thousands of people instantly, and led to the “Year without summer” in 1816, which resulted in famine and civil unrest worldwide over the next decade.
As super-eruptions go, Mount Tambora was a small one. A single super-eruption can expel hundreds to thousands of cubic kilometers of magma in just days or months. And according to a study published in the journal PLOS ONE, these devastating volcanic events only give about a year’s warning before they blow.
Researchers from Vanderbilt University and the University of Chicago conducted a microscopic analysis of quartz crystals in pumice taken from the Bishop Tuff in California, which is where the super-eruption that formed the Long Valley Caldera occurred 760,000 years ago.
“The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales,” said study lead author Guilherme Gualda in a press release. “Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption.”
The quartz crystals they analyzed are remnants of the original underground magma, and have distinctive rims that are rich in titanium. By making high-resolution measurements of variation in the titanium, the researchers were able to record the transition from pre-eruptive crystallization to the decompression and crystallization at the time of the eruption.
They found that the processes leading up to the blast occurred over a span of under a year. “More than 70 percent of rim growth times are less than 1 year, showing that quartz rims have mostly grown in the days to months prior to eruption,” the authors write.
With the possibility of another potentially civilization-ending super-eruption striking the Earth some time in the future, this study offers new insight into the timescales over which such an event would occur.
You might also like: North Korea’s Mysterious Supervolcano May Be Ready to Blow