The city of Quito lies on geological faults that have no surface outcrop but are moving with a speed of 2-4 mm per year. The last strong earthquake associated with these thrust faults, was rec-orded in 1587 and had a magnitude of 6.4; so it has been more than 400 years, there is a large amount of stored energy, and the probability of an earthquake occurring is very high. Therefore, this article presents, firstly, the periods of recurrence of these faults; then a microzoning of the north central part of the city and the elastic response spectra for 5% damped associated to the Llumbisi- La Bota segment fault, ILB.
And subsequently, an analysis of nine steel structures from one to nine storeys assuming that they are situated in the following three areas of north central Quito: the old Quito Tenis; La Gasca and Benalcazar High School. Using the Capacity Spectrum Method MEC, the seismic response is found with the presence of three spectrums as prescribed in the Ecuadorian Construction Regula-tions NEC-11; the recommendation in the study of the seismic microzoning of Quito ERN-12 and those found in the seismic microzoning associated with the fault ILB.
Three types of responses are indicated for each location, the structures situated in the old Quito Tenis present a performance point found using the Capacity Spectrum Method MEC; for those in La Gasca, a maximum lateral displacement is indicated in each storey; and the structures situated in the Benalcazar High School present maximum interstorey drifts. It should be highlighted that the lateral displacements and interstorey drifts are reaching the end of their performance, thus the conclusions to be found in this study about which spectrum the maximum response has could be inferred from any of the three structural parameters.
DESING SPECTRUMS FOR THE CENTRAL NORTH OF QUI-TO AND SEISMIC ANALYSIS OF STEEL STRUCTURES USING THE CAPACITY SPECTRUM METHOD.