We love to see patterns in everything. For example, you may catch some fish in a bay, and think they should always be there when you come back. Most likely you'll never catch a fish there again!
In fact, the human desire for patterns invariably leads to putting false patterns on everything. If you spray some random red dots on a seismicity map, and you expect to see lines, you will see lines. If more dots are sprayed, you will see more lines that are completely different! This is an unstable pattern, with the inevitable surprise, which you see all the time with hedge funds, and the stock market!
In the 90's we were being killed with false patterns (and dramatic conclusions) hitting the newpapers. People would look at the inaccurate historical seismicity maps, along with complex geo-magnetic maps, and come up with a catchy soundbite of doom. At the time we were terrible with counter-soundbites. They would interview some rambling engineer for 2 hours, and it would be cut to 10 seconds .... "There will be damage......"
I decided that this Death of a Thousand Soundbites, could be addressed with some real science, and the management was beat up so bad that they actually listened! I set up a plan in my head to put in some decent seismic monitoring all over southern Ontario. This became the Southern Ontario Seismic Network (lots of credit to other people, blah, blah). As well, we started to improve the regional geophysics.
I knew from other seismic networks (notably New Madrid), that real patterns would emerge if we could get location accuracy down to about 1 km. That's why I hustled to get some 'real' money into this. There was no use in just installing 1 seismometer! We started with 6 and then expanded.
After umpteen years of operating, we finally have 'real', stable patterns that aren't blown away by tomorrow's data. The seismic picture has never been that rosy for the Toronto area, but we have been subject to the worst 'false' patterns of all: that of living memory:
-Foam can't hurt anything (Space Shuttle)
-Don't remember when we had a big hurricane (Katrina)
-We don't need to do anything special about earthquakes (Toronto emergency bureaucracy)
Here is a picture of the latest seismicity around Toronto.
You only have to combine this with deeper crustal structure to start seeing something. The calculated Seismic Hazard speaks for itself, but there is a real danger of sucked into Soundbite Land, which is to be avoided at all costs!