Identificación de las zonas de mayor amplificación sísmica en la mancha urbana de Chiapa de Corzo, Chiapas como herramienta para evaluar la vulnerabilidad física por exposición

Abstract

The city of Chiapa de Corzo located in the center of the state of Chiapas, is located in one of the most active seismic regions of Mexico. Local soil conditions have determined the seismic amplification of the site creating patterns in the damage observed after the occurrence of major earthquakes, such as the one that occurred on October 6thof 1975 that provoked radical changes in the habitants of the city, and the most recent of September 7 of 2017 of Mw 8.2.This paper presents a proposed seismic zoning for regions without studies of environmental vibration through a simplified methodology, which constitutes a variable to evaluate the physical vulnerability by exposure of constructions in cities with homogeneous constructive systems in materials, ages and pathologies. The proposed methodology uses geological parameters, soil and the inclusion of two crucial variables such as flood zones and historical damage by earthquake. According to the results of the algebra of maps were obtained two zones, a higher amplification where 85% of the damage were recorded for both earthquakes. The main inputs were digital cartography, field trips to identify the constructive pathologies of the structures that presented damage and processing through GIS-type software. Finally, the vulnerability was determined by exposure to seismic amplification in each block in the urban area of Chiapa de Corzo, using the amplification regions as a determinant variable to describe vulnerable constructions by exposure. For risk management this technique allows select the houses that must be reinforced, repaired or built with higher safety standards.