Contribución a la historia sísmica de la sierra sur de Ecuador: estudio macrosísmico de los terremotos del 29 de junio de 1887 y del 5 de septiembre de 1893

Abstract

Historical seismology studies in Ecuador have primarily focused on the central and northern highlands of the country. This work, framed within a project to review the historical seismicity of Azuay, concentrated on the macrosismic study of the two most intense earthquakes in the known seismic history of the province: those that occurred on June 29, 1887, and September 5, 1893. The following three aspects were addressed: 1) historical research, 2) assessment of macrosismic information, and 3) macrosismic analysis of the earthquakes. Regarding historical research, emphasis was placed on newspaper archives. The macroseismic analysis obtained three results for each earthquake: a) identification of their seismic sequence pattern, b) approximate epicentral area, and c) assessment of their maximum intensity. The most significant result was the reassessment of the maximum intensity of the 1893 earthquake at IX–X (EMS-98 scale), representing an increase of about two degrees compared to that recorded in the country's historical seismic catalog. It was deemed pertinent to begin with a critical review of the state of historical seismology in South America and Ecuador.