Editor’s Note: Reporter Amelia Heagerty joined radio personality Dave Ross on the Dave Ross Show on KIRO 97.3 on Friday to discuss the “Vashon Hum.” Check it out HERE. The original story about the “Vashon Hum,” published April 14, appears below.

Even if you don’t hear the hum, your neighbor may.

It could be crashing ocean waves, the wind whipping around the house or a nearby construction site. But those who hear a persistent low-frequency hum on Vashon — from pragmatists who say the hum must have an explainable source to those who believe it could be the Earth’s good vibes — say it isn’t going away and may even be getting louder at times.

The “Vashon Hum” is a very low pure tone that people have heard all across the Island. Some hear it in their yards, while others have heard it in beachfront homes and at Island Center Forest. It’s not a menacing or terribly annoying sound, Islanders report, but those who hear it are fascinated by it and wonder where the hum originates.

The cause of the hum — which is in good company with widely reported hums in places such as Taos, New Mexico, and Kent, England — hasn’t been pinpointed, but experts and Islanders have weighed in on what it may be, and what it isn’t.

“I would describe it as a very low, deep sort of humming sound, with a vibration resonance quality to it,” said Islander Tami Brockway Joyce, who has heard the hum at her westside home off Cove Road, in Island Center Forest and in Dockton. “At first I thought it was the dishwasher running, or some kind of motor running in the background. But my husband and I are hearing it all the time now.”

Intrigued but also annoyed by the noise, Brockway Joyce recently posted a comment about the hum on her Facebook page. More than 20 people from Vashon and around the country replied, with countless theories for what the hum could be — from wind tunnel testing to low-frequency military communication.

“I’m super-curious about it,” Brockway Joyce said. “It has definitely piqued my interest. I’m constantly thinking, ‘What could it be?’”

Patti McClements, who works at Vashon’s Puget Sound Energy office, said she’s never heard, or heard of, such a hum. But she said staff at the utility office could investigate the hum if Islanders report where and when they hear it.

“Sometimes the transformers do buzz, but if people are hearing it at the ground level and it’s not coming from above, then I don’t know what to say,” she said.

Described as “The Hum” by Wikipedia, the noisy phenomenon has been investigated in several continents and reported on by media including Time Magazine, The Guardian and The Daily Telegraph. Happening in such land-locked places as New Mexico, some believe the sound is land-based.

But it couldn’t be coming from the earth, said geologist Greg Wessel.

“There have been times I’ve heard a sound like that and wondered what it was, but we live on the north end, and I assumed it’s traffic coming from the ferries,” he said. “It could be sounds due to atmospheric pressure or sunspots. But I’m pretty sure there’s nothing geologic that’s responsible for it.”

On the other hand, the hum couldn’t be coming from underwater, according to oceanographers and mechanical engineers.

“It would just not be physically possible for that to be an underwater-based source,” said Peter Dahl, an associate professor in mechanical engineering at the University of Washington and a principal engineer at UW’s Applied Physics Laboratory. “I would say most likely it’s an industrial-based sound or a residential sound, a land-based source.”

Though ships, marine animals and rain can cause sounds in water — some quite loud — it’s highly unlikely Islanders could hear a marine-based sound as deep inland as Island Center Forest, even something as loud as a container ship traveling on the west or east side of the Island, said Chris Bassett, a University of Washington mechanical engineering graduate student who studies underwater ambient noise.

“Sound travels very well in the water, but very poorly in the ground,” added Jim Thomson, an oceanographer at the University of Washington Applied Physics Laboratory. “Sound in the ocean is complex, and it can propagate and do things that are audible to humans. … But I’d be surprised if that could make an entire Island hum or travel very far inland.”

In 2009, a study was published in Geophysical Research Letters that identified a worldwide marine hum caused by ocean waves in the Pacific crashing together, colliding with the sea floor and creating a sound underwater. But the sound is likely too quiet to be heard at the surface or by humans, reported Wired.com.

Perhaps it’s the wind, said Islander and oceanographer Stefan Talke, whipping past large objects such as thick tree trunks or houses.

“Wind velocities can easily get up to 10 meters a second,” he said. “You could easily hear the wind humming. … I think it’s much more likely to have that kind of a sound with wind than with water as a low frequency.”

Still, Islanders with normal hearing say they’ve heard a hum under normal conditions with no explainable source.

Islander Jeff Hoyt recalled a time last week when he and his wife were watching television and both heard the hum.

“We turned off the sound system, and I could still hear it,” he said. “It’s almost like a motor or a thrum, and we’ve only noticed it in the past week.”

Islander Amber Tjemsland said she never heard the hum when she lived on Cemetery, but since moving to Cove, she often hears a “barely perceptible” sound that she’d describe as a pulsing noise.

“I suspect it goes on all the time, and occasionally the sound goes up into the range where our human ears can hear it,” she said.

Whenever she hears the noise, she said, her two goats seem to hear it, too. They act agitated and nervous, pawing the ground and retreating to their shelter.

“They’ll look this way and that with their ears up,” Tjemsland said. “They just seem unsettled. … They do the same thing if they see an eagle or hear an airplane.”

Some Islanders, like Shelley van Spronsen, have heard the hum ever since moving to the Island. She first heard the hum seven years ago, right after she came to Vashon.

“It wasn’t really unsettling to me,” she said. “It sounds a little rumbly, but it doesn’t sound like it’s coming from a certain direction. It doesn’t seem like a bad noise.”

Some, like Tom Dean, the Vashon-Maury Island Land Trust director, say they haven’t heard the hum but suspect it has a practical explanation.

“Could it be coming from the landfill?” he asked.

But a King County official quickly debunked that theory.

“The couple things we’ve got going (at the Vashon Transfer Station) are an aerator that runs 12 hours a day and a gas extraction system that’s pulling out methane and other gases and runs 24 hours a day,” said Doug Williams, a spokesman for the King County Department of Natural Resources and Parks, which oversees the county’s Solid Waste Division. “Both are running properly and have been running since the early ’90s. I can’t imagine them being loud enough to carry off the property.”

In fact, the noise could be the Earth speaking to those spiritually tuned to hear such sounds, said Lorna Cunningham, a longtime Islander and intuitive who recently opened Vashon Intuitive Arts at a shop in town.

“As soon as you mentioned it, I could feel a hum or a vibration in the Earth,” she told a reporter.

“This is a time of change in the world, and people who are attuned to it could possibly hear something like that. It’s almost like music of the Earth. But it doesn’t come to me as something that’s mechanical at all.”