One hundred twenty years after discovering that we could look inside our own bodies using X-rays, scientists at the University of California, Berkeley, have found a way to look inside Earth itself. In the first ever 3D CT scan of Earth, seismologists have managed to create a “sharp, three-dimensional scan of Earth’s interior” that, among other things, details the origins of volcanoes. By looking into the paths of seismic waves that traverse Earth’s interior, the team at Berkeley has linked mantle plumes deep underground with surface hotspots that produce volcanic activity in areas like Hawaii, Samoa, and Iceland.
Due to the high resolution of these latest maps, scientists are able to determine quite conclusively — and for the first time ever, no less — that these large areas of remarkably hot rock beneath Earth’s crust are actually directly related to hotspots above Earth’s surface. Moreover, these mantle plumes can be enormous, ranging from between 600 and 1,000 kilometers across and clocking in at 400 degrees Celsius warmer than the surrounding rock. That being said, there aren’t always areas of particularly warm mantle directly underneath volcanoes — as senior author Barbara Romanowicz notes, many of these plumes begin to “thin out … meander and deflect” as they make their way up towards the cooler parts of the mantle.
Study first author Scott French told Berkeley news sources, “No one has seen before these stark columnar objects that are contiguous all the way from the bottom of the mantle to the upper part of the mantle,” making their discovery particularly novel. This latest advance in the study of Earth’s interior marks the first of many steps that are still needed to understand what goes on underneath our planet’s crust, even as we continue to learn more about what goes on above it.
Moving forward, Romanowicz says, scientists may be able to combine existing techniques “with very sensitive gravity measurements from satellites and maybe electromagnetic sounding” to further their studies. But until then, this CT scan certainly beats what you’ll see at the doctor’s office any day.