Science, Technology, Linux, Earthquakes, Education, Geology, Nuclear. My retirement blog. I was a geophysics engineer with a big utility, doing earthquakes for Ontario.
How would the gardiner due in an earthquake and what do you feel is the largest earthquake we should expect in the Hamilton - Toronto corridor.
I expect the Gardner to do poorly, given it's constant state of non-repair, and (probably) shallow foundations on fill. They have very little room on the expansion joints, so I might expect a slab or two to let go.The Hamilton fault is self-similar to about 30 km, so I expect an M6. With amplification, I expect the soft areas to exceed the critical threshold of 50 cm/s PGV. Toronto and Burlington are on the hanging wall side of the fault, and, so, get the full hammer. This type of earthquake has about a 1 in 500 chance per year, the limit of the Building Code, and maybe the same hazard as Greek islands.
And another boo-boo! Self-similar to 30 km means an M7, which is too ugly to contemplate! An M6 will shut down all the power and gas, but it probably takes an M6.5 to drop slabs on the Gardner! Still, an M6.5 hovers at the 10-2 to 10-3 per year zone.
Very interesting.How would a wood framed house sitting on stiff clay in North Burlington stand up if an M7 quake were to strike along the Hamilton fault.
My general rule is that if it's a bitch to sink in a fence post, then you're mostly ok. Burlington is right at 'ground zero', so I would expect to lose the chimney, and everything from the shelves. The drywall would be ratshit, but there shouldn't be any collapse. Far worse are some of those tall houses built in the sag pond along the 403 into Hamilton. Yuck!
This is a facinating subject. If you think we could be in for an M7 earthquake, why does most of the seismicity seem to be out in the lake rather than in Hamilton City limits and Dundas valley (none within Burlington)? The other thing I wonder about is why we only see shallow depth earthquakes and nothing recorded over M4 in Hamilton. In my discussions with a professor at UWO running the SOSN, he expects maybe an M5 in the lake but stated the chances of getting hit on the head by a meteorite were greater than us getting an M7 earthquake. Do you really think an M7 is possible? Looks like I should investigate earthquake insurance.Not arguing, just really curious. I am certainly not a geoscientist, just a civil engineer with an interest in this area.I really appreciate your quick responses!
The uncertainties are huge! It's highly expected we should get an M5, since 2 have happened over in the sister zone of Cleveland. So the odds are about 1 in 100, perhaps. For an M6, maybe 1 in 1000, and M7 1 in 10,000. But I think there is a lot of slop in the numbers, and I think an M6.5 should be the scenario-planning earthquake.There is also the largest size earthquake where fractal self-similarity breaks down. Many places are just fractured blocks with maximum blocks just a few km's. You won't see anything more than an M6! That's why I think earthquakes out in the lake are limited to M5 or so.The Hamilton fault is smooth to 30 km, and I think it could produce something much greater than expected. A smooth fault in the midst of fractured rock does not act in a rational manner. It can produce characteristic large earthquakes.Don't bother with earthquake insurance. Make sure your chimney is in good repair, or take it down, if that doesn't make things too ugly!You can read more about Hamilton in earlier posts.
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