Abstract

San Juan de Pasto, capital of the Department of Narino (Colombia), is located in a high seismic hazard region, according to the Regulations for Earthquake Resistant Design of Buildings. The city has been affected by several earthquakes throughout its history associated with the main seismotectonic sources in the country such as the Algeciras, Romeral, and Afiladores fault systems and the subduction zone.

A review of the historical earthquakes that have significantly affected (intensity ≥7 on the EMS-98) San Juan de Pasto city was carried out to contextualize, classify and evidence recurrent damage, which provides an approach to determine possible site effects in the city. There are other issues that also influence the site effects such as the soil condition and topography of the area, but these are not considered in this study.

The earthquakes selected were on January 20, 1834, October 26, 1935, and July 14, 1947, which significantly damaged many structures in the city. For every case, the type of affected structure, its constructive vulnerability and the degree of damage were analyzed, taking into account the historical context of each period. These data were georeferenced on the city map, and it was observed that there are common areas that have been affected by all the seismic events.