When the authorities say, “There’s nothing to worry about,” do you immediately start worrying? Then get out your beads because the experts who monitor the magma underneath the Yellowstone National Park and its surrounding area say satellite images of the park show a “mysterious patch of bright pixels” that turned out to be a newly formed “tree kill zone” and an area of dead vegetation that wasn’t there before. (Insert “Nothing to worry about here.”)

“Recently, we have discovered another phenomenal example of thermal change—the emergence of an entirely new thermal area, which has taken place over the past 20 years!”

If it’s nothing to worry about, why the exclamation point at the end of a blog post in Caldera Chronicles, a weekly article written by U.S. Geological Survey Yellowstone Volcano Observatory scientists? For good measure, they put another exclamation point at the end of the title, “Discovering new thermal areas in Yellowstone’s dynamic landscape!”. This can’t be a good sign!!! The only thing worse would be if they told us NOT TO WORRY IN ALL CAPS!!!

“Analysis of a Landsat-8 nighttime thermal infrared image acquired in April 2017 revealed an unexpected warm area between West Tern Lake and the previously mapped Tern Lake thermal area. This mysterious patch of bright pixels in the thermal infrared image did not match any previously mapped thermal areas.”

“Mysterious patch.” No exclamation point but it was enough for the USGS to do some historical analysis on the remote Tern Lake and West Tern Lake area. What the scientists found, using images from the Landsat-8 National Agriculture Imagery Program (NAIP), was that there was no anomaly in this location in 1994 photos and a small patch of dead vegetation in 2006 images. On the other hand, the 2017 image showed:

“The area of bright pixels identified in the Landsat-8 thermal infrared image corresponds to a newly emerging area of warm ground and tree kills about 32,500 m2 (8 acres, or 4 soccer fields) in area.”

Four soccer fields! (Our exclamation point this time.) This indicates something even more mysterious … why did they measure this kill zone in soccer fields rather than the tradition U.S. measurement of football fields?

To soothe worried Yellowstone supervolcano watchers, the blog article points out that a ‘thermal area’ is a cluster of “thermal features (like fumaroles, hot springs, or geysers) surrounded by hydrothermally altered ground, hydrothermal mineral deposits, geothermal gas emissions, heated ground, and/or a lack of vegetation. While there are over 10,000 thermal features in Yellowstone, most are in just 120 distinct thermal areas like Upper Geyser Basin, Norris Geyser Basin and Tern Lake. Because the area is so large and the thermal areas are generally in remote locations, satellites are needed to monitor them. In its “nothing to worry about” comment, the USGS says:

“This is exactly the sort of behavior we expect from Yellowstone’s dynamic hydrothermal activity, and it highlights that changes are always taking place, sometimes in remote and generally inaccessible areas of the park. We will continue to keep an eye on Yellowstone using satellite imagery and report on any changes we see in future Caldera Chronicles articles.”

Will we have to wait another 11 years for an update on the tree kill zone at West Tern Lake? Here come the last exclamation points:

“And if you’re really interested, you can check out the Landsat-8 data and airborne NAIP images for yourself! All images are freely available from https://earthexplorer.usgs.gov. Have fun!”

Fun? Exclamation point ‘Fun!’ is an amusement park, not a supervolcano park.

Worried? Worried!