DO YOU HEAR SOMETHING?

posted by / News / July 1, 2003

It’s 3 a.m. and you can detect the beginning pulse of an early winter swell rumbling in the darkness outside. But what you’re hearing isn’t the actual waves pounding on the shoreline. In fact, you’re miles inland. What you’re listening to is the surf’s infrasound frequencies, the latest theory to hit swell forecasting

“You know how we use our five senses — especially our eyes and our ears when surfing.” Milton Garces, Director of the University of Hawaii’s Infrasound Laboratory, explains. “Well, we just added to that an extension of sound.”

Garces, along with Mark Willis and others stumbled upon this potential tool when they took part in a project that monitors clandestine nuclear testing in the atmosphere. Luckily, they never honed in on such tests and instead ended up hearing frequencies from things like volcanoes, meteors, spacecraft re-entries, and especially, swells.

“We started noticing all these little bleeps coming in and at first didn’t know what it was, then we isolated them to the water,” Garces says. “And then winter came, and the whole coastline just lit up in bleeps.”

Don’t kill your WAM links just yet. The advantage in infrasound is not predicting a swell days before it arrives but in its pinpoint accuracy to provide a researcher with the tools to determine the best locations for surf.

“In January there were a lot of big swells hitting the [Big] Island, so we installed acoustic antennas along the coast,” Garces says. “Ultimately, we determined the direction of the swells’ arrival, pointed [the antennas] around to see where the energy was coming from and ended up finding things like the peak of the swell, fluctuations because of tides and where they hit the hardest — just a lot of precise structure.” Basically, Garces says, you don’t even have to be near the coast and with infrasound you will know exactly where to find the area’s best spot for surf — right down to the peak.

The researchers at the University of Hawaii believe that this new technology will enable our current forecasting tools to be more accurate and precise.

“When you look at WAM, those models have a one degree resolution, that’s about {{{100}}} kilometers of coastline, what that doesn’t give you is a lot of coast specific dynamics in that area, and that’s what surfing’s all about,” Garces explains. “And with LOLA, they’re building on these larger models and then building some topographic-specific information into it — the problem is how to verify this info. Infrasound is a system that will allow these models to be validated and tested on a finer and finer scale.”

Garces hopes that his team’s work will spark more research around the nation, especially on the North Shore this winter, simply because infrasound waves are undeniably accurate. And just how in depth is Garces getting to prove infrasound’s precision?

“The next time your sitting out there listening to the waves, just imagine the lowest frequency you can hear, and then go deeper,” Garces answers. “That’s where we’re at.” Andrew Lewis

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