Greater Sudburians felt the Earth move Tuesday afternoon when two minor earthquakes struck northwest of Lively, events big enough to rattle some windows, but not do any serious damage.
The first at 1:55 p.m. measured 3.3 on the Richter Scale, while the second at 2:15 p.m. measured 3.8.
According to Earthquakes Canada, the epicentre was seven kilometres northwest of Lively. The latitude was 46.48, the longitude was 81.19, and it took place at a depth of 5.4 kilometres below ground.
Catherine Woodgold, a seismologist with Earthquakes Canada, said Tuesday that reports from this area are common but are normally related to mining.
“But this one was bigger, so we're presuming it was an earthquake,” Woodgold said. “Mining blasts don't usually get this large. (Although) that magnitude is not expected to cause damage.”
She said there are normally about four earthquakes this size in Canada each year, mostly in parts of British Columbia and Quebec. With the geology in Northern Ontario, the risk of a serious event is low.
“There's a very small possibility of having damaging earthquakes in that area,” Woodgold said.
About 80 online reports have been filed with them so far, she said. An earthquakes that registers higher than 4 may cause some minor damage, while things get more serious at 5.
Overall, the northeastern Ontario Seismic Zone has a low level of seismic activity, according to the Earthquakes Canada website.
The zone runs from Sudbury in the east, Fort Frances and Red Lake in the West, Winisk in the North and south of the Sault in the south. Between 1970 and 1999, on average, only one or two magnitude 2.5 or greater earthquakes have been recorded in the zone per year.
“By comparison, over the same time period, the smaller region of Western Quebec experienced 15 magnitude 2.5 or greater earthquakes per year,” according to information on the website.
Since they began keeping statistics, two magnitude 5 earthquakes – one in 1905 in northern Michigan, and again in 1928, northwest of Kapuskasing -- have occurred in the region. The biggest in eastern Canada was recorded in 1935, when Temiscaming was shaken by an earthquake of magnitude 6.2.
Besides Tuesday's events, there is one other earthquake
in the magnitude 3 range in the last 10 years in the area close to Sudbury, a magnitude 3.1 in 2001. Here's a full list:
July 11, 1997: 2.1, 26 km east of Espanola
July 29, 1997; 2.7, 64 km southeast of Lively
Aug. 12, 1997: 2.6, 50 km southeast of Sudbury
July 27, 1998: 2.0, 45 km southeast of Sudbury
Dec. 23, 1999: 2.3, 58 km west of North Bay
Feb. 19, 2000: 2.3, 61 km west of North Bay
Sept. 26, 2001: 3.1, 50 km west of North Bay
Dec. 27, 2002: 2.2, 60 km west of North Bay
March 26, 2003: 2.3, 20 km east of Sudbury
Sept. 2, 2003: 2.5, 24 km southwest of Sudbury
May 27, 2007: 2.1, 53 km southwest of Sturgeon Falls
Aug. 5, 2014: 3.3, 6 km northwest of Lively
Aug. 5, 2014: 3.8, 7 km northwest of Lively