The one accelerograph record obtained from the Managua earthquake of December 23, 1972 indicates that maximum ground acceleration was 0.39 g. Observations of severe damage to buildings in the center of the city and seismoscope records indicate that accelerations exceeding 0.5 g may have occurred within the zone of surface faulting. For the main shock, the horizontal components of the maximum response spectra show that the predominant periods are about 0.5, 1.0 and 1.7 sec; the vertical component shows high-velocity response for periods of 0.2 and 1.3 sec. Maximum response amplitudes for the main aftershock were in the same general period range as the main shock, although somewhat lower. For the main shock, levels of response in the horizontal direction of 40 to 60 cm/sec lasted between 4 and 8 cycles for many periods less than 1 sec. These levels of response, together with the high predominant periods of less than 1 sec, correlate well with observed damage to buildings.

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