5.5 Earthquake Hits Canada; Felt in US Midwest, New England 560
joelmax writes "A magnitude 5.5 earthquake hit central Canada this afternoon, rattling buildings from Windsor to Montreal to several US states. The epicentre of the quake was in Quebec, 61 kilometres north of Ottawa, according to the US Geological Survey, and struck at 1:41 pm EDT." If you felt this quake, it would be great to put your location in the title of your comments, below — with lat/long coordinates even better.
Shaking in Ottawa (Score:5, Interesting)
I was in a boardroom on the 6th (top) floor of our building for a 1:30 pm meeting and just as we're getting underway the table and chairs were shaking. Was pretty heavy for about 20 seconds and then faded off over the next minute. We're a lot of government buildings so the policy is to evacuate. We actually tried to continue our meeting but then they finally got to our floor to check it out they found us and told us to leave. As you can guess, no more work is really being done today. It's pretty exciting for us as we don't get this here.
One interesting note, when I did go outside most everyone was on their cell phone and several were stating that they couldn't get service. I would guess because of the increase in volume at that time.
Re:I felt it....ohhh wait. (Score:2, Interesting)
Football. There are no football teams in America. There are lots of American Rugby teams
FTFY
Known hazard area (Score:5, Interesting)
It's in part of Canada that is prone to earthquakes, extending roughly along the Ottawa and St. Lawrence River Valleys. The increased activity along here is related to two factors: 1) this is an old "suture" [wikipedia.org] where pieces of continents were accreted onto the rest of North America a long time ago (the later half of the Paleozoic [wikipedia.org]) culminating in the building of the Appalachian Mountain system (the Appalachian Orogeny [wikipedia.org]); 2) the suture stopped being an active plate boundary after the continental pieces were fused onto the continent, but crustal stress still occurs because of the relatively "recent" melting of the continental ice sheets ~10k years ago. The weight of the couple kilometres of ice during the glaciation depressed the crust, and much of central Canada has been experiencing isostatic rebound [wikipedia.org] (i.e. rising back up again) ever since the weight was removed. That process slowly deforms the crust, and when the stress gets too great the rock moves, generating earthquakes. The stress tends to get released along old zones of crustal weakness (i.e. #1).
This seismic hazard map [nrcan.gc.ca] by the Geological Survey of Canada shows the increased risk along the St. Lawrence River rather nicely. More details here [nrcan.gc.ca].
Having said all that, the level of activity in this part of Canada pales in comparison to earthquakes in the area of an active plate boundary, such as California, where the deformation rates are higher, the earthquakes more frequent, and often higher magnitude. It means that building codes along the St. Lawrence-Ottawa River Valleys are fairly strict when it comes to earthquake resistance, just in case, but a significant earthquake is still outside most people's everyday experience. I'm sure people are freaking out (I'm ~1000km away, so I felt nothing).
43.5073,-80.5296 (Score:1, Interesting)
Felt my desk shaking here, although some half of my coworkers didn't feel it.
Re:5.5? Feh! (Score:3, Interesting)
Wimps?
2" of snow would make you cry for weeks. In Ottawa, we finally caved in and cheered for an extra 6" so we could break the 170" record only a few years ago. It's all about what you're accustomed to.
Heads will roll (Score:4, Interesting)
Any word on who they're planning to charge for failing to predict this monster?
Kingston Ontario, 44.227644,-76.491965 (Score:4, Interesting)
Re:5.5? Feh! (Score:3, Interesting)
Yeah. In Chile we laugh at you California people making big deal of 7.0 magnitude earthquakes. Here those are called aftershocks.
For the record -- I was 60 miles from the epicenter of the 8.8 on February 27th. The quake wasn't that bad, but the aftershocks every 15 minutes for the next 3 days got tiring.
Re:5.5? Feh! (Score:4, Interesting)
In Kitchener ON. Stuff was rattling on the shelves here... about 150 miles southwest of the epicenter.
The largest earthquake ever recorded in the U.S. was in 1964 in Alaska [wikipedia.org]. It was 9.2 on the Richter scale. The second largest measured earthquake. In contrast the New Madrid Earthquake [wikipedia.org] (about 150 miles south of Saint Louis on the Mississippi River) was estimated from 7.5 to 8.1. However, the geology of the Midwest (one big piece of underlying bedrock covering most of the U.S. Midwest and Southern Ontario) allows the effects of an earthquake to be felt with little diminishment quite far from the epicenter, unlike earthquakes in zones like California (where the effects are not transmitted anywhere near as far). The underlying reason for the New Madrid Earthquake Zone looks to be a failed rift valley causing a weak spot in the sheet of bedrock covering the Midwest.
Also, ca. 300 years ago there was an estimated 8.7 to 9.2 Megathrust Earthquake off the Cascadian coast in 1700 [wikipedia.org] (off the west coast of North America from mid Vancouver Island in B.C. Canada, and down along Washington and Oregon States. This was large enough to cause a large tsunamis to strike the coast of central Japan. It is expected that this area will experience this type and magnitude periodically (every ca. 500 years). I know in Vancouver, and most of coastal B.C. for that matter, that extensive earthquake retrofitting has taken place, and new buildings have to meet tough earthquake codes.