March 18, 2015

A whole lot of shaking going on


I was sitting at my desk in my office on Monday afternoon around 4:30 when the door out to the porch startling rattling and shaking. 

It was a sunny, mild day with no wind to speak of.  The house was quiet and the noise got my attention.  I watched and listened for maybe 10 or 15 seconds and the rattling ended.

So, no wind. No storm clouds on the horizon. No one was running up my steps.  I didn't hear any trucks rumbling around the neighborhood.  No aircraft noise from above.

Suddenly, it was just quiet again.

I will admit that I thought about an earthquake -- now that I am a veteran.  My first was in August 2011 just days before Hurricane Irene hit the island when a 5.8 magnitude earthquake --- centered outside of Richmond in northern Virginia -- shook much of the East Coast.

I'd never experienced an earthquake before, and when it happened, I was standing in my living room watching The Weather Channel. However, there was no question in my mind but that it was an earthquake.

The rattling on Monday was different from that -- it was more noise than motion and I heard it more than I felt it.

I quickly put it out of my mind and moved on with work.

Then it happened a second time -- around 6 p.m.  Again I sat and watched and listened.

Interesting, I thought to myself and moved on with work.

Later that night and yesterday, I read that other folks had also felt the shaking and that, although it apparently wasn't an earthquake, no one really knew what it was.  As usual, there was plenty of speculation.

I had other news stories to pursue today and it was two days after the event, so I decided I really didn't need to write an article about the curious shaking and rattling.

Until it happened again.

I was sitting at my desk again this afternoon when the porch door started rattling loudly. I was startled.  It couldn't be happening again.  Could it?

I looked at the time - 3:59 p.m. I stopped what I was doing and watched the door shake --again for 15 seconds or so.  And, again, it suddenly stopped.  The wind had stopped blowing. No one running up the steps.  No trucks rumbling around the neighborhood.  No aircraft noise.

This time I decided to see if others were also hearing or feeling the movement, so I posted on the Island Free Press Facebook Page and the replies started rolling in -- dozens of them.

Yes, other folks felt it, heard it, whatever.  In my neighborhood in Brigands' Bay, other areas of Frisco, Buxton, Avon and up to Kitty Hawk and Kill Devil Hills. On Monday, folks reported the rumbling from up in Virginia Beach and out on the Eastern Shore.

I was talking on the phone with Donna Barnett about the shaking a few minutes after I posted -- and it happened again.  This time at 4:13 p.m. This time I could also feel the chair shaking.

And this time, I had to try to figure out what was happening, so I got online, found phone numbers, and started making calls.

I ended up talking with Don Blakemore,  a geophysicist at the United States Geological Survey National Earthquake Information Center in Golden, Colo.

After listening to we had experienced, Blakemore said he hates to always blame it on the military, but when he gets these calls, that is usually the cause.

"Typically," he said, "it's the military causing sonic booms."

I assured him that we were used to sonic booms out here on the barrier islands, and that this was not a sonic boom.  He said that you don't always hear or feel the "boom" with a sonic boom -- sometimes it's just the energy causing shaking or rumbling or whatever.

He checked all his seismological data and assured me that we had not experienced an earthquake.

He did say that a 2.8 magnitude earthquake was measured early on Sunday morning, March 15, near Louisa, Va., which is just outside Richmond.

He said he had a few calls on Monday, but there was no earthquake that day -- or yesterday or today.

I asked Blakemore about seismic cannons that might be in use offshore in oil and gas exploration. He said he had some experience with seismic testing, and what we experienced was also probably not seismic testing.

"That's much lower energy," he said. "And it's not a one-time can go on and on for hours."

In other words, we probably wouldn't experience seismic testing with periodic shaking or rumbling.

So, I guess we are left with the idea that it was probably the military -- with some kind of training or exercises.  That's fairly common off the coast, but just try to find out when it is happening or if it is causing our shaking phenomenon.  The military doesn't really share that kind of information -- or at least I've never found a public information officer chatty enough to discuss it.

We'll keep asking and let you know if we find out more.

Meanwhile, let us know if you feel more of our strange shaking, rattling, and rolling.

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