19 September 2018 marks the anniversary of the 2017 Central Mexico earthquake that killed 228 people in Mexico City, damaging almost 6000 buildings with more than 40 collapsing. This video explains why the earthquakes in Mexico City are so strong and how the seismic-warning systems work. Seismic waves in Mexico City are intensified locally because the city is built on the sediments of an ancient lake.
For further reading, Lucina Melesio has written an article for the September 2018 issue of Physics World examining how the development of early-warning smartphone apps could help save lives in the future.
