Tuesday, February 23, 2010

Mysterious sounds and shaking ground continue in Pelham

By Terry Date

PELHAM — Cracking ice, earth tremors or tractor-trailers bouncing off frost heaves. None explain the all-hour booms and earthshaking in northern Pelham the past several weeks, according to residents who reported them. Neither do blasting, power lines arcing nor frost cracking or snow thunder.

Maj. Tim Acerno of New Hampshire Fish and Game said freezing ice that expands to the shore and has nowhere to go can cause a sharp sound like a gunshot, but it does not cause the ground to quake.

Besides, several people who reported the incidents said Beaver Brook is the only water nearby.

Resident Bill McDevitt said he does not think freezing brook water drove him and his wife from bed at 4 a.m. on Feb. 2.

Massachusetts Institute of Technology seismology professor Stephane Rondenay said the source is not likely earthquakes. Typically, they cause shaking, but not bangs.

In any event, the U.S. Geological Survey has not registered ground-shaking seismic events in the past 30 days in the area.

Some people have suggested that an empty tractor-trailer or one loaded with steel might make a loud noise when it hits a frost heave.

Roger Chiodi of Tallant Road has heard the noises before and they were not what he and his wife experienced three weeks ago about 3 p.m. He was outside, working on his snowmobile. His wife was inside the house.

They both felt the ground rattle. His wife ran outside, fearing the snowmobile had fallen on top of him.

Then, on Feb. 11, about the same time of day, he and his wife were both inside the house when they felt the house rattle.

It scared their dog, who was "barking like crazy," he said.

Jay Levine, supervisor for the Interstate 93 widening project, said blasting is not allowed at night. And the Pelham location is a long way from I-93 for people to be hearing loud noises, he said.

The director of planning in Pelham knows of no commercial blasting at these times. He has conferred with the fire chief, who would know if blasting was taking place, and there has been none.

The mystery has both of them perplexed and intrigued.

"It's really interesting and I'm baffled," planner Jeff Gowan said. "It's so strange."

Pelham fire Chief Jim Midgley said he received an e-mail from someone on Thursday who wondered if shorts in power lines were causing arcing and booms.

Some people who have heard the noise describe it as being like a transformer exploding or an airplane breaking the sound barrier.

David Graves, a spokesman for National Grid, said there have been no reports of arcing or power outages in that area.

New Hampshire climatologist Mary Stampone said the cracking of frozen ground might explain ground shaking and loud noises, if they were happening in very cold places like Alaska or Russia.

Snow thunder can be loud, but the weather was cold and dry earlier in the month, she said. Stampone said one thing to consider is that noise carries differently in the winter during cold, dry weather.

"When the air is still, you can hear things from farther away," Stampone said.

There is less vegetation to buffer sound in the winter, as well.

Yet, the mystery remains.

"It's fun to speculate, but I haven't heard anybody with a reasonable explanation," McDevitt said.

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