Yesterday we lived through the scariest quake I can remember. In the one from September 19th 1985 I was too young, and none of us could foresee the terror that would follow. In the one from September 7th this year, the quake alert sounded like a minute before the quake hit and, though it was an 8.2 (0.1 magnitudes stronger than the 1985 one), it was some 700km away, so it wasn't felt as strongly. But yesterday's one? The epicentre was just some 110km away, so there was no time for the quake alarm to warn us – it caught us all by surprise. At a magnitude of 7.1, where I was at the moment it felt like a giant mace was repeatedly trying to smash the building by hitting it from above. The rumble was so loud and encompassing. Absolutely undeniably survival-instinct-level terrifying.
Buildings collapsed, including a school and apartment buildings in the most hip areas of the city. Civil brigades self-organized quickly, with apparently little or no government supervision at first. There are many lessons to be learned from this frightening and horrible experience, and hopefully this will serve as a really painful reminder to never let our guard down and always to step up our game.
09/23/2017 Update 1: A friend pointed out the gap between two buildings in my second photo was there before and remains the same. Hard to tell accurately, but this would mean that the centre of the city withstood the quake remarkably well.
09/23/2017 Update 2: The sister of a friend is a seismologist. She explained the ground acceleration registered at the UNAM (National Autonomous University of Mexico) during this earthquake was 6% of gravity, while the acceleration registered at the exact same point in 1985 was 3%. No wonder it felt so horrible, and it does speak incredibly well of the application of building regulations since 1985.