EARTHQUAKE DAMAGE, MEXICO CITY, SEPTEMBER 19, 1985
Graphic Showing Types of Buildings Damaged
Medium-height buildings were the most vulnerable structures in the September 19 earthquake. Of the buildings that either collapsed or incurred serious damage, about 60% were in the 6-15 story range. The resonance frequency of such buildings coincided with the frequency range amplified most frequently in the subsoils. Diagram credit: C. Arnold, Building Systems Development, Inc.