The map, by the United States Geological Survey (USGS), reveals that the terrain around the volcanic cauldron (caldera) has indeed been shifting over the past couple of years. The soil above Yellowstone’s Norris Geyser Basin has moved up by 7centimeters (around 3 inches) in that time period, and within the heart of the caldera itself, the ground has dropped by 3centimeters (1.2 inches).
So what’s going on down below? First off, the ground around Yellowstone caldera, like plenty of active volcanic systems around the world, is always moving to some degree. In fact, this recent deformation – which was mostly calculated using radar technology – is comparable to Yellowstone’s activity just a few decades earlier.
Yellowstone caldera is a dormant volcano with a very active volcanic system operating beneath it. As well as having a series of magma chambers filling up beneath it, it is also a landscape riddled with fault lines that slip and shift on occasion.
Hydrothermal fluids – superheated water-rich liquids driven by the heat of the magma – are also zipping through the subterranean landscape, and occasionally make their way to the surface in the form of geysers and hot springs. All three of these are likely responsible for the changes in local topology.
Yellowstone supervolcano is not about to catastrophically erupt. If it did, it would likely be a very limited lava flow which would probably kill a total of zero people. In any case, the chance of any major eruption happening this year is roughly one-in-730,000.
As iflscience website reports.