A professional surfer named Maya Gabeira surfed the year’s biggest wave, The New York Times reported. Nearly 75 feet high, it was the highest wave ever surfed by a woman and the highest wave surfed over the 2019-2020 season in general. Ocean waves are measured by distance, time, and speed.
According to The New York Times, the news about Maya Gabeira’s record-breaking run may have come late, but it came with big news. “This month, a team of private wave engineers and scientists with the Scripps Institution of Oceanography and the University of Southern California Department of Aerospace and Mechanical Engineering determined the wave Gabeira rode [on February 11] was 73.5 feet, smashing her own previous record by more than five feet,” the article said.
“Gabeira’s run beat out the 70-foot wave surfed by the Nazaré Tow Challenge champion Kai Lenny, also on February 11. It was a Danicka Patrick moment for big wave surfing.”
The science of measuring ocean waves is one involving height, length, and time.
A Disturbance in the Force
“Waves are disturbances, and so ocean waves, just like all waves of any type, are simply disturbances of a medium that transmit energy while not actually transferring mass, at least not transferring it very far,” said Dr. Harold J. Tobin, Professor in the Department of Earth and Space Sciences and Director of the Pacific Northwest Seismic Network at the University of Washington in Seattle.
Dr. Tobin used the example of dropping a stone into a pond and watching the water ripple outwards from the point of impact.
“It creates a little disturbance of the surface of the water, and that disturbance is a little high,” he said. “It has a little potential energy because of the change of elevation in the surface of the water. That moves outward because the water wants to flatten itself out, which then disturbs the next bit of water and on and on and on.”
However, the water of a wave doesn’t really travel with the wave. It follows a very similar pattern to an object floating on the water’s surface—it travels one direction and upward, then back in the other direction and downward. This is because waves are simply a propagation of force.
Anatomy of a Wave
“Waves have crests and troughs—they have highs and they have lows,” Dr. Tobin said. “The difference between the high and the low is defined as the wave height. Sometimes we talk about wave amplitude, and it turns out amplitude is half of height because amplitude is defined from the kind of zero line to either the crest or the trough.”
The wave length, Dr. Tobin said, is the horizontal distance between a point on a wave and the same point on the following wave—for example, one wave crest to another wave crest.
Meanwhile, the wave period is the same idea, but measured in time. A point on one wave crashes on a certain location, and the time it takes for the same point on the next wave to crash is the wave period. The wave length, divided by the wave period, is the wave speed.
“Speed is generally distance divided by time, and so wave length is distance; wave period is time; and so the wave speed is just distance over time,” Dr. Tobin added.
Dr. Harold J. Tobin contributed to this article. Dr. Tobin is Professor in the Department of Earth and Space Sciences and Director of the Pacific Northwest Seismic Network at the University of Washington in Seattle. He earned his BS in Geology and Geophysics from Yale University and his PhD in Earth Sciences from the University of California, Santa Cruz.