Effect of soil conditions on damage in the Peru earthquake of October 17, 1966

Abstract

abstract This earthquake was centered offshore, 140 miles north of Lima. A strong motion record at Lima indicated a peak acceleration of 0.4g, and several pulses of 0.3g. The earthquake caused severe damage to many adobe and quincha houses and to some modern reinforced concrete structures in Lima, where the observed damage indicated MM intensities from VI to VIII. At towns closer to the instrumental epicenter the MM intensities ranged up to a maximum of about IX. There was some indication that the higher intensities were associated with the poorer soil foundation conditions. This was especially true where the soil and foundation conditions were particularly bad, but the trend was less definite where the soils provided good to fair foundations. Damage to well built tall buildings and other modern structures was mostly limited to broken windows and cracking in wall panels. In the few cases where modern structures did sustain more serious damage, it appeared to be due to inadequate provision for seismic forces in the designs, or to poor construction practices. Some slumping and landslides developed in dry sands and partially cemented granular soils.