The 2010 Central Canada earthquake occurred with a moment magnitude of 5.0 in Central Canada on 23 June at about 13:41:41 EDT and lasted about 30 seconds. The epicentre was situated in the area of Buckingham, Quebec, approximately north of Ottawa, Ontario, closest to the settlement of Val-des-Bois, Quebec. Canada's capital, Ottawa, declared this earthquake as being its most powerful in 65 years. It was felt across most of Ontario and Quebec, as well as parts of the northeastern United States, in addition to places as far as Chicago, Pittsburgh, Baltimore, Charleston, West Virginia, and Halifax. It was the first moderate earthquake associated with the Western Quebec Seismic Zone since 20 April 2002, when the area was affected by magnitude 5.1 Mw tremors. Southern Ontario was also affected by the 1998 magnitude 5.2 Mw Pymatuning earthquake, associated with a different seismic region (Southern Great Lakes Seismic Zone). Although a 5.0 magnitude quake is considered to be moderate, the earthquake's depth (estimates of which vary between and ) meant that its effects were more widely felt. Geology The magnitude 5.0 Mw intraplate earthquake occurred near the southern edge of the Western Quebec Seismic Zone, known for frequent, but minor tremors, occurring, on average, every five days. Far away from the North American tectonic plate's margin, the regional seismicity is controlled by a series of geologic faults formed over the last billion years by the processes of mountain building, including the Grenville orogeny, and subsequent erosion. The processes causing the earthquakes in the zone are not well understood: the tremors are not linked to particular seismogenic structures, nor are the sources of stress definitively identified. The initial focal mechanism of the 2010 earthquake suggests reverse faulting on a fault trending southeast–northwest. However, the size and depth of this earthquake make it uncertain whether the causative fault can be identified. Earthquakes of magnitude 4.5 or greater are fairly infrequent in the area, occurring at a rate of a few per decade. Some studies suggest, however, that larger earthquakes of magnitude around 7 may have occurred 4550 and 7060 years BP. Earthquake The Globe and Mail reported that "Twitter users as distant as Springfield, Massachusetts, Traverse City, Michigan, and Cincinnati, Ohio reported feeling tremors." The blogosphere and other social media sites like Facebook were swamped by posts referring to the "2010 Ottawa earthquake" or the "2010 Toronto earthquake". Places all the way southward to