Soft soil makes Mexico City shake like it was built on jelly
WASHINGTON (AP) — The soft soil that lines the ancient lake bed that Mexico City is built on amplified the shaking from Tuesday’s earthquake and increased its destructive force, seismologists say as they try to better understand the quake that has killed more than 200 people.
Scientists are looking at other quirks of the magnitude 7.1 earthquake, including the absence of aftershocks and if it is somehow related to a distant, even stronger, Mexican temblor that struck a dozen days earlier.
Mexico City is built on deep, soft soil that was once the bottom of a lake. Instead of cushioning the city from earthquakes, it exaggerates their effects, said James Jackson, a professor of geophysics at the University of Cambridge in England.
The vibrations, or seismic waves, from the hard rocks below are amplified by the soil and sediments above, making the surface — and the structures built on the surface — shake longer and more intensely.