Site effect and damage distribution in Pujili (Ecuador) after the 28 March 1996 earthquake

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 17; no. 5; pp. 329 - 334
• Main Authors: Guéguen, Philippe, Chatelain, Jean-Luc, Guillier, Bertrand, Yepes, Hugo, Egred, Jose
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.1998; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Earthquakes, seismology; Ecuador; Exact sciences and technology; H/ V spectral ratio; Internal geophysics; Pujili; South America; Ecuador; America; Ecuador; H/ V spectral ratio; Pujili; Case study; structure soil interaction; Reinforced masonry; Natural damage; Earthquakes; Construction materials; Alluvial plain; Urban area; Spectral analysis; site effects
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/S0267-7261(98)00019-0

The 28 March 1996 earthquake ( Mw=5.7) produced extensive damage in Pujili, a small town located in the central part of the Inter-Andean valley of Ecuador. Variations in the damage rate of adobe constructions throughout the city let us suppose a ground motion amplification related to site effects. A site effect study using the H/ V spectral ratio confirmed the good agreement with geological formations and showed that a second peak in some soil response appears at sites that are located over a zone of alluvial deposits, in the most damaged area of the city. This second peak is in the frequency range 5–7 Hz, close to the natural response of adobe building frequency. Thus, the second peak seems to increase the damage rate of adobe buildings and may be related to superficial alluvial deposits of a river, acting independently of the rest of the soil column.