Yellowstone is unique because it sits on top of one of the world's largest volcanoes. Super-volcanoes can erupt spontaneously, without the need of an external force (Photo : National Parks Service )

The volcanic system beneath Yellowstone National Park is bigger and better connected than anyone previously believed, according to researchers presenting at the Seismological Society of America's annual meeting.

"We are getting a much better understanding of the volcanic system of Yellowstone," said Jamie Farrell, a seismology graduate student at the University of Utah, as reported by LiveScience. "The magma reservoir is at least 50 percent larger than previously imaged."

Computer models of the shape of Yellowstone's magma chamber reveal that it occupies a continuous space, not separate chambers, and that the space is much larger than previously believed.

The magma chamber is the source of the park's hydrothermal springs and geysers and is responsible for "surface uplift" seen in the park, LiveScience reported.

"This crustal magma body is a little dimple that creates the uplift," said Bob Smith a seismologist at the University of Utah and author of a related study presented at the meeting. "It's like putting your finger under a rubber membrane and pushing it up and the sides expand."

According to information by the National Parks Service, the last time the Yellowstone volcano erupted was 640,000 years ago, leaving behind a caldera 30 by 40 miles wide.

In 2011, a study reported that volcano beneath the national park was rising at unprecedented rates, which is nothing to be alarmed by, as this trait is common in volcanoes around the world.

"It's not a portent of doom," said Erik Klemetti, a volcanologist at Denison University in 2011. "It seems like these restless calderas are always sort of rising and falling, but that by itself doesn't mean it's about to erupt."

The National Parks Service has a detailed fact sheet about the Yellowstone volcano, which indicated that there is no imminent or expected eruption for the next 10,000 years.