El terremoto de Patillos del 30 de diciembre de 1952 (Ms= 5,9) y el contexto neotectónico de la región del volcán Irazú, Costa Rica

Abstract

The Patillos earthquake of december 30, 1952, occurred on the western side of Irazú volcano, and was one of the most destructive earthquakes affecting central Costa Rica, during the seismic cycle of 1951-1955. lt produced large landslides in a region with high slopes, high pluviosity and young volcanic units. A Mercalli Modified intensity study of the earthquake, defines that the maximum intensity was VIII, the macroseismic epicenter was located to the northwest of volcano (geographical coordinates 10°01' lat N and 83° 54' long W), at a focal depth of 14 km and with a local magnitude M_L= 5,2. A neotectonic study allowed to define the main faults of the lrazú area. We relate the earthquake with the northwest trending Río Sucio fault. A review of seismicity occurred in the period 1930-1993, defines different active seismic sources in the region. The focal mechanisms are predominantly strike slip with normal and reverse components, and the maximum horizontal compressive stress directions are trending between NW and NE. We associate these stress changes to the interaction between the regional stress that trends NNE, with local stress fields related to magmatic processes.