Plate tectonics pioneer challenges the way Earth works

As an undergrad at MIT in the 1950s, Lynn Sykes ’59, SM ’60, became interested in the theory of continental drift, which held that the world’s great landmasses had wandered across Earth over time. The theory had been proposed most notably by Alfred Wegener in the early 20th century, but it was largely considered outlandish by the scientific community. “I was told that decent graduate students didn’t work on such crazy ideas,” he remembers. A few years later, however, he made a discovery that would help prove its legitimacy.  

At the Institute, Sykes was inspired to work in the field of oceanic seismology by a first-year geology course with the late professor Bill Brace ’46, ’49, PhD ’53. After earning a bachelor’s and master’s in geology and geophysics, Sykes pursued his doctorate at Columbia University, where he studied deep-ocean earthquakes. It was there that he discovered a curious phenomenon in the South Pacific—a line of earthquake activity revealing a 600-kilometer-long fracture zone that had never been observed before. Sykes discovered a similar phenomenon in the Atlantic north of Iceland. They turned out to be the first evidence of a transform fault, a feature proposed by the Canadian geophysicist John Tuzo Wilson in which seismic activity occurs in a rupture between two ridges, leading the seafloor to spread and continents to move.  

The data, presented at a conference in 1966 by Sykes, showed that continental drift—now known as plate tectonics—was indeed occurring. “It was recognized right then and there, and by a number of people who previously thought it could not and did not exist,” says Sykes, who is now recognized as one of the progenitors of the concept. That claim to fame is just one instance in which he has tilted against conventional wisdom. 

Even as a child, Sykes was aware of how attention to scientific evidence could lead to unexpected conclusions. He recalls an instance in which his father, a weather forecaster, used data to predict a bout of extreme cold one Thanksgiving weekend. In 10th grade, Sykes received an award for an essay on the then-nascent theory of global warming. “It led me to believe that there were important societal things science could contribute to, and I wanted to be a part of that,” he says.

Sykes became a professor at Columbia’s Lamont-Doherty Earth Observatory after earning his PhD and turned his attention toward monitoring seismic waves from underground nuclear testing. In the late 1960s, many doubted that underground nuclear tests could be distinguished from earthquakes, prompting the belief that a treaty banning underground testing would be impossible to enforce. Sykes proved naysayers wrong by identifying differences in their seismic signatures. “People said there were numerous ways Russians could cheat, and along with others, I was able to show that was not the case,” he says. He testified before Congress and traveled to Moscow for the signing of the Threshold Test Ban Treaty in 1974. 

Through continued research, Sykes showed that it was possible to detect even tiny seismic waves from nuclear tests, leading to the 1996 Comprehensive Nuclear-Test-Ban Treaty, which banned all nuclear explosions on Earth. 

Now 87, Sykes is still challenging ideas about the way Earth works. This February, he published a controversial paper about earthquakes along California’s San Andreas Fault, arguing that events such as the devastating 1989 Loma Prieta quake in San Francisco could have been predicted from signs occurring decades in advance. “In the future, knowing those signs can help us take steps to strengthen sites years ahead of time,” he argues. That idea runs counter to the prevailing belief that the locations of future earthquakes are impossible to know. 

For Sykes, it’s not about being right or debating people; he just follows the data to help solve problems. “I think that these are important problems,” he says. “That’s what I emphasize.”