The Yellowstone volcano is located in the Yellowstone National Park, between the US states of Wyoming, Montana and Idaho. The caldera is labelled a supervolcano due to its capability to inflict disaster on a global scale should a supereruption occur. It last witnessed an event of this kind more than 630,000 years ago and has not seen any serious eruption in 70,000.
On August 1, 2013, the Steamboat Geyser erupted for the first time in eight years, surprising scientists and visitors alike.
Located in the Norris Geyser Basin, it is described as the “Holy Grail” of geysers because no one knows when it will go off.
Jacob Lowenstein, who is in charge of monitoring Yellowstone for USGS, revealed a graph showing the increase in the temperature recorded on that day.
He told students during a lecture at Menlo Park, California, in 2014: “In this case [the graph] is related to the eruption of Steamboat Geyser – it’s Yellowstone’s tallest and sends water over 300ft into the air.
“Last summer [2013] Steamboat erupted again, you can see that here from a temperature gauge that we have in the outlet right below the geyser.”
Dr Lowenstein then revealed how, when analysing what had caused the eruption, USGS scientists noticed a “big spike” in temperature.
He continued: “And here is time on the bottom, and right there is when there was a big spike in temperature, a couple of hundred feet away from the geyser itself.
“And you can also find that about a mile away and an hour later, there was a big spike that went out through a steam gauge on Tantalus Creek.”
He revealed how the rise in temperature and pressure build-up caused the geyser to erupt for an hour, before calming down again.
He added: “Another neat thing that you can see with this particular diagram is that before the eruption there were all these tiny little peaks.
“These represent small eruptions of Steamboat sending water maybe 15 or 20 feet in the air.
“As soon as the big eruption occurred water came out for an hour, then nothing came out of the geyser anymore.
“So all you see here is a nice flat curve that represents the daily variations in temperature.”
Dr Lowenstein revealed during the same lecture how USGS scientists recorded “a lot of earthquake activity” more than a decade ago.
In December 2008, continuing into January 2009, more than 500 earthquakes were detected under the northwest end of Yellowstone Lake over a seven-day span, with the largest registering a magnitude of 3.9.
Dr Lowenstein said: “These are seismograms and they are from the south and north end of the lake.
“All of the data is for December 27, 2008, and come from the Yellowstone Seismic Network.
“You have the time starting from early (top) to late (bottom) and every 15 minutes is represented by the black line – so four would be an hour.
“And these are all earthquakes, every time you get a squiggle you are looking at an earthquake.”
Dr Lowenstein went on to reveal how, although the earthquakes were not particularly strong, they were still felt in the park.
He added: “It was in December though, so there weren’t a lot of people around.
“But there were maybe 15 or 20 people who were living near the lake at the time and they felt it.”