Lava From Space

Iceland! Satellites! Volcanoes!

Late last month, the Holuhraun lava field in central Iceland spasmed with earthquakes as lava began spewing from it once again. Now two weeks into its spurt of activity, its lava flow stretches 10 miles long and covers eight square miles. It’s the island nation’s biggest volcanic event since the 19th century.

And you can see it from space.

Earlier this week, the U.S. government’s Earth-observing Landsat 8 satellite passed above Holuhraun and caught it in action. Landsat is the oldest continually operated program of its kind: Its satellites have been capturing images of the Earth since the Nixon administration.


Note that both of these images are false-color: They’re not exactly what you would see were you to peer out the window of the International Space Station and look down. The Landsat sensors read light from 11 different “bands” of the electromagnetic spectrum, and only five of those are visible to the unaided eye. Of its six other bands, three measure infrared light and two measure heat.

These images combine two infrared bands and the “green” band. This makes the incredible heat and energy of the lava flows visible, while also allowing us to see greenery and other common land features nearby.

But the lava flows even appear in “true-color” images. Here, for example, is the same image, but with only the visible bands:


The fire of the lava is still visible, though it’s not as vivid as in the infrared treatment. Zoomed out slightly, and the redness all but disappears—though the noxious smoke it emits remains huge across the landscape, a reminder of the wider consequences of any local disaster.