Experts examining site of Doaktown-Boiestown tremblor

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Charles Perry
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Seismologists are carefully examining the site of an earthquake and aftershock that occurred in the Doaktown-Boiestown area of northeastern New Brunswick on Sunday, which literally shook up many householders and motorists.

Seismologists are concerned about the possibility of more aftershocks to come.

Earthquakes will not only be followed by aftershocks, but often another earthquake, says Dr. John Ebel, director of the Weston Observatory and a geophysics professor at Boston College. And the latter can occur as long as a week or more after the original earthquake, he said.

The seismic activity from the earthquake Sunday morning in New Brunswick registered between 3.4 and 3.6 on the Richter Magnitude Scale,

The activity was cited by the New England Seismic Network at the Weston Observatory, which recorded it as being 86.2 kilometres (53.6 miles) north-northeast of Fredericton. Residents reported floors, roofs and car seats shaking, but no injuries or damage were reported.

The Weston Observatory operates a network of broad-band seismometers which are distributed throughout the New England states, but also pick up activity in New Brunswick because of its proximity to Maine. The network has been monitoring earthquakes in the area for the past 75 years.

Ebel said they picked up the earthquake activity and had its site and magnitude recorded within minutes.

He said Canadian seismologists will be on the site analyzing the disturbance and monitoring the area to determine what further aftershocks or earthquakes might follow. Unlike volcanoes, he added, when and where earthquakes occur cannot be predicted.

And this also applies for follow-up tremors, said Ebel.

In 2006, an earthquake in Bar Harbor, Me, measuring 3.4 on the Richter scale, similar to Sunday's one in the Doaktown-Boiestown area, was followed a full week later by another earthquake at the same site.

The second one measured 4.2 on the Richter scale and therefore caused much more damage, said the geophysics professor.

The Richter scale gauges the magnitude of earthquakes between one and 10, he said, adding you would not feel an earthquake with a measurement of one, while a 10 would be as bad as it could get.

An earthquake with a 4.7 reading in the Saguenay region of Quebec occurred in the morning, said Ebel. It was followed that evening by a second earthquake measuring 5.7 on the scale.

Other earthquakes, some of which are severe, will have no aftershocks or follow-up earthquakes, he said.

"It is hard to know what to expect. Each earthquake is unique in itself."

Ebel said New Brunswick is no stranger to earthquakes. He said a 1982 earthquake, whose epicentre was in Plaster Rock, had a 5.8 designation and could be felt for hundreds of kilometres.

n Charles Perry's Weather appears daily.