ESPECTROS DE ENERGÍA DE MOVIMIENTOS FUERTES REGISTRADOS EN MÉXICO

SUMMARY An analysis of the input energy in the valley of Mexico for some strong earthquakes is presented. Input-energy, acceleration and velocity response spectra of epicentral stations are qualitatively correlated with the damage. Some results were included to discuss the definitions of absolute and relative energy and the time variation of the energy. The attenuation characteristics and the energy variation with magnitude and direction of motion for places at the lakebed zone of the valley of Mexico are briefly commented. Besides, the variation of the input energy spectra and the hysteresis spectra with respect to the strength and ductility demand is commented. Finally, the elastic spectra of input energy and normalized hysteretic energy for the earthquake of April 25 1989 and the corresponding maps with curves of equal energy for four structural periods are shown. These curves are drawn for a structural period of two seconds for four earthquakes that had an important intensity in the valley of Mexico.