https://montrealgazette.com/news/local-news/minor-earthquake-hits-montreal-area
Montreal just isn't as prepared as LA & SF, Sydney & Auckland, especially Tokyo. So if a very intense earthquake ever hits, the city could get quite a jolt.
https://en.wikipedia.org/wiki/Montreal#Geography
Only one of_the_tallest_office_buildings_in_Montreal has been permitted to have 51 stories. There are some residential buildings with more floors.