Mexico City 1985 And 2017 Earthquakes: Soil Response And Code Lessons

Mexico City is one of the worlds most tectonically active regions, with a long history of destructive earthquakes and volcanic eruptions. With over 100 earthquakes of magnitude 6 or higher since 1787 and poor subsurface conditions, Mexico City is a modern metropolis with challenges for architects, urban planners, engineers, developers and stakeholders.On September 19th, 1985, a M8.0 earthquake in Michoacan killed more than 40,000 people and caused 880 buildings to collapse in Mexico City. At the wake of its 32nd anniversary, the 2017 M(w)7.1 Puebla-Morelos earthquake struck, leaving behind about 219 dead and 38 collapsed buildings in Mexico City.This paper will present similarities and differences of the two events in aspects of: (i) geotechnical and seismological observations, (ii) building code evolution and its impact to building response, and (iii) analytical predictions of response of characteristic soil profiles at sites with actual recordings of the ground motions.