This slow divorce is hidden in plain sight, seen in scars that dot the country. But the most striking example lies at the edge of the Reykjanes peninsula where a footbridge visually displays this growing fissure between the two continental plates-at a small but noticeable 2.5 centimeters (about an inch) a year.
How do we know it’s moving at this crushingly slow speed? The same technology you use to navigate while driving.
Today, we think of GPS as a directionally challenged motorist’s best friend, but in the field of geodesy, GPS is something much more. “We are learning the direction of the plates’ movement, how (they are) interacting with volcanic systems, and the retreating of glaciers,” says Benedikt G. Ófeigsson, GPS specialist in the Icelandic Meteorological Office. “(But) the main insight we are gaining is that the (Earth’s) crust is really dynamic.”
Ridicule and Redemption
To understand how GPS revolutionized Earth science in just 30 years, you need to know the low-tech ways scientists used to study the Earth for centuries. For centuries, scientists hypothesized that the continents were moving. In the 16th century, Flemish cartographer and creator of the first modern world atlas, Abraham Ortelius, theorized that natural phenomena like earthquakes and floods had torn the Americas away from Europe and Africa.
It would be a couple more centuries for German meteorologist Alfred Wegener, who first proposed the “theory of continental drift” in 1912, to begin fashioning our modern understanding of what’s happening under our feet. Wegener’s hypothesis concluded that all the continents were once joined together in one large landmass known as a “supercontinent,” but millions of years ago it broke apart and the continents slowly drifted to their present-day locations.
Like many forward-thinking scientists, Wegener was ridiculed for his ideas at the time. His German colleagues said he was having “delirious ravings” and that he was sick with “moving crust disease and wandering pole plague.” Today, however, we know that Wegener was much closer to the truth than any of his doubtful contemporaries. But to find the evidence to back up his theories, the world would have to go to war.
Roger Revelle, the U.S. Navy’s chief oceanographer, called the mid-20th century “One of the greatest periods of exploration of the Earth…every time you went to sea, you made unexpected discoveries…nothing that we expected was true. Everything we didn’t expect was true.”