What would you do if you knew a nearby supervolcano would erupt in exactly one year? Buy supervolcano insurance? Start a business selling supervolcano insurance? Run like hell? Those are all viable options and the one-year warning may happen based on new research on historical evidence of events leading up to past supervolcano eruptions. (So far, “run like hell” is leading in early polls.)
According to their report in PLOS One, Guilherme Gualda, associate professor of earth and environment sciences at Vanderbilt University, and Stephen Sutton from the University of Chicago studied small quartz crystals from the Bishop Tuff (a tuff is a formation of welded volcanic rock) in eastern California where a supervolcano erupted 760,000 years ago and formed the Long Valley Caldera. Their analysis focused on the surface rims of these crystals (along with rims on crystals from other supervolcanoes) which are an indicator of age.
The researchers used a new method of studying the quartz crystals based on the amount of titanium in them. Titanium is an impurity in quartz that can indicate timescales, but it has been previously difficult to measure. Their new technique involves cathodoluminescence – measuring the light produced when quartz is blasted with electrons. Variations indicate growth rates and timesspans.
What did Gualda and Sutton find?
Maximum rim growth times span from approximately 1 minute to 35 years, with a median of approximately 4 days. 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.
Rim growth is caused by decompression – the activity in the underground magma chamber that releases the gas bubbles that expand the magma body to fuel the eruption.
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 good news, according to Gualda, is that decompression should be detectable on the surface above or near its occurrence a year before an eruption. The bad news is, scientists don’t know yet what the surface signs of decompression are and more research is needed and hopefully underway.
In the meantime … wanna buy some supervolcano insurance?