Nova Scotia earthquakes come in waves, geologist says
Alan Ruffman says Maritime earthquakes have bursts of energy every few decades
The tiny earthquake that wobbled Nova Scotia on Canada Day could be a sign that a big one is about to devastate the province, but it's probably not.
Sometimes a string of small quakes indicate a big one is coming and National Resources Canada confirmed that at 3:32 p.m. on Wednesday, a small quake hit 60 kilometres southwest of Digby, off the coast of Tiverton in the Gulf of Maine between Nova Scotia and Grand Manan Island in New Brunswick.
Locals thought a plane had crashed as their windows rattled on the day the Earth didn't stand still.
If you have a whole lot of little earthquakes, the question is: will we also have a big earthquake?- Alan Ruffman
The area has recently experienced a string of smaller quakes along the continental shelf near Shelburne, says Alan Ruffman, president of Geomarine Associates Ltd. He is also an honourary research associate at Dalhousie's Department of Earth Sciences.
So is the end nigh?
"This has got some researchers interested," says Ruffman. "If you have a whole lot of little earthquakes, the question is: will we also have a big earthquake?"
He says Atlantic Canada tends to be hit by waves of small quakes every few decades, and that can ultimately lead to a big quake. The last time multiple earthquakes really shook homes in the Maritimes was at end of the 1800s, he says.
Ruffman said he wasn't surprised to hear of the 3.6 magnitude tremor.
"They seem to have bursts of energy," he says. "We're not immune. We have earthquakes … at the mouth of the St. Lawrence River or the Laurentian channel. And we appear to have two [fault lines] in Nova Scotia, off of Shelburne to the south and certainly one at the mouth of the Bay of Fundy."
But people have only been measuring seismic activity for 100 years, Ruffman says, so we don't really know what's going on.
"When's the next big one? Nobody knows."
Ruffman says Nova Scotians shouldn't be concerned. Unlike Canada's west coast, there aren't subduction zones in Atlantic Canada where ocean floors and tectonic plates push downward underneath the continent.
More information is still needed to better understand Nova Scotia's fault lines.
"We need some more instruments in southwest Nova Scotia, and I would argue along the U.S. border in New Brunswick," he said.
So the bottom line on the earthquake is that Nova Scotians should shake it off.