Influence of Site Characteristics on Building Damage during the October 3, 1974 Lima Earthquake

摘要

In the city of Lima in the past 30 years six earthquakes, with surface wave magnitudes from 6 to 7.6, ground surface accelerations as high as 0.4g and durations of strong ground motion well over one minute, have caused unusually low levels of damage in the city itself. A magnitude 7.5 earthquake originating some 90 km. west of Lima on October 3, 1974 offered an excellent opportunity for investigators to attempt to explain why damage in Lima is generally lower than in other places of the world subjected to similar earthquakes, and to understand the reasons for the pattern of damage observed as a result of this and previous earthquakes. An investigation was carried out that included a study of the structural characteristics of buildings in Lima, the damage and the distribution of damaged buildings during the October event, analysis of available data, additional field investigations to classify subsurface conditions and to measure material properties, and an analysis of the strong ground motion data. Specifically, it was desired to find out whether local subsurface conditions could have influenced the damage and the distribution of damage caused by this and previous earthquakes in the Lima area. The results of the investigation form the subject of this report.