It's a field day for EQs. M3.9 ONTARIO-QUEBEC BORDER

[Chacor]

http://earthquake.usgs.gov/earthquakes/ ... 10tgbh.php

Magnitude 3.9 - ONTARIO-QUEBEC BORDER REGION, CANADA
2010 February 28 03:51:22 UTC

Earthquake Details
Magnitude 3.9
Date-Time

* Sunday, February 28, 2010 at 03:51:22 UTC
* Saturday, February 27, 2010 at 10:51:22 PM at epicenter
* Time of Earthquake in other Time Zones

Location 45.752°N, 74.447°W
Depth 5 km (3.1 miles) set by location program
Region ONTARIO-QUEBEC BORDER REGION, CANADA
Distances

* 35 km (22 miles) W (265°) from Saint-Jérôme, Québec, Canada
* 37 km (23 miles) WNW (284°) from Mirabel, Québec, Canada
* 48 km (30 miles) W (281°) from Blainville, Québec, Canada
* 60 km (37 miles) WNW (292°) from Laval, Québec, Canada
* 73 km (45 miles) WNW (291°) from Montréal, Québec, Canada

Location Uncertainty horizontal +/- 40.3 km (25.0 miles); depth fixed by location program
Parameters NST= 12, Nph= 12, Dmin=126.5 km, Rmss=1.09 sec, Gp=259°,
M-type="Nuttli" surface wave magnitude (mbLg), Version=7
Source

* USGS NEIC (WDCS-D)

Event ID us2010tgbh

[Macrocane]

That's very unusual for that region, isn't it?

[jinftl]

Actually, parts of eastern Canada have high seismic activity. A 1925 earthquake off the coast of New Foundland measured 7.2 in magnitude. It generated a tsunami that killed 27 in New Foundland. More recently, on November 25, 1988 the largest earthquake in eastern North America in 53 years occurred 35 km south of Chicoutimi, Québec and measured a magnitude of 5.9.

Per Natural Resources Canada, an agency of the Canadian government,

Each year, approximately 450 earthquakes occur in eastern Canada. Of this number, perhaps four will exceed magnitude 4, thirty will exceed magnitude 3, and about twenty-five events will be reported felt. A decade will, on average, include three events greater than magnitude 5. A magnitude 3 event is sufficiently strong to be felt in the immediate area, and a magnitude 5 event is generally the threshold of damage. The seismograph network of Earthquakes Canada can detect all events exceeding magnitude 3 in eastern Canada and all events magnitude 2.5 or greater in densely populated areas.

The causes of earthquakes in eastern Canada are not well understood. Unlike plate boundary regions where the rate and size of seismic activity is directly correlated with plate interaction, eastern Canada is part of the stable interior of the North American Plate. Seismic activity in areas like these seems to be related to the regional stress fields, with the earthquakes concentrated in regions of crustal weakness.


http://earthquakescanada.nrcan.gc.ca/ha ... az-eng.php

That's very unusual for that region, isn't it?