This week, Professor Jackson has spoken to multiple news sources, detailing the reasons why the second of these earthquakes has had quite such devastating effects.
Professor Jackson explains that Mexico City is built upon soft, deep, soil which was once at the bottom of a lake. Rather than cushioning the effects of seismic events, the vibrations of the hard rocks below this soil are amplified by the sediment above, making the surface (and structures built upon this surface) vibrate more intensely. Jackson has said that ‘it’s like being built on jelly on top of something that is wobbling’.
According to Professor Jackson, these very same soft sediments were the reason behind the devastating effects of both the 1985 Mexico City Earthquake, and a similar process amplified the effects of the deadly 2015 Nepal earthquake.
For more information, you can read one of the articles here: http://abcnews.go.com/Technology/wireStory/soft-soil-makes-mexico-city-shake-built-jelly-49986622