[meteorite-list] Mysterious Blast Shakes Nanaimo, Canada

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:29:54 2004
Message-ID: <200309111816.LAA22094_at_zagami.jpl.nasa.gov>

http://www.globeandmail.ca/servlet/story/RTGAM.20030911.wnama0911/BNStory/National/

Mysterious blast shakes Nanaimo
Canadian Press
September 11, 2003

Nanaimo, B.C. -- Was it a sonic boom, a dynamite blast, or an
asteroid hitting the earth?

Government and local emergency services were stumped Wednesday
afternoon, unable to explain a powerful blast that shook
Nanaimo from stem to stern.

The blast, which occurred around 1 p.m., was heard and felt as
far south as Chemainus, and as far north as Nanoose.

Nanaimo RCMP say no damage or injuries had been reported.

One thing is fairly certain: it was not an earthquake,
although it did register on a seismograph in Nanaimo.

"From the signature of the wavelength, it does not look
like an earthquake, it looks like an explosion," said Alison
Bird, an earthquake seismologist with the Geological Survey
of Canada.

There were reports of dynamiting on Mount Benson.

But dynamiting requires a permit, and the Ministry of Energy
and Mines, the City of Nanaimo's public works department and
the Regional District of Nanaimo all said there were no
permits issued for any blasting Wednesday.

A Ministry of Forests spokesman in Port Alberni also said he
was not aware of any blasting or road building going on Mount
Benson.

A spokesperson with Comox air base said there were no jets
in the area Wednesday that would have been capable of
creating a sonic boom.

Nor was the army engaged in artillery practice.

A shock and blast expert at the University of Victoria says
the weather patterns Wednesday were nearly perfect for
sound wave refraction, which could mean the blast may have
come from some distance.

"You may get focusing of a blast, which may come from a lot
further away than you think," says Dr. Alex van Netten of
the University of Victoria's physics department.

Under certain weather conditions, sound can refract, and
the focal point may be many miles away from the source.

The sound may actually be louder at the focal point (many
miles away) than it is in the immediate vicinity of the
explosion.

"Today is a typical day, with clouds, when you'll get a
temperature inversion," he said Wednesday. "This is a
classic situation where you have a focusing of sound. It
might be further out than you think. It might even be in
Vancouver."
Received on Thu 11 Sep 2003 02:16:03 PM PDT