DETERMINACIÓN DE PROPIEDADES DINÁMICAS DEL SUELO EN LA POBLACIÓN DE CUMANACOA, REALIZADOS PARA MICROZONIFICACIÓN SÍSMICA, 2006 I DETERMINATION OF DYNAMIC PROPERTIES OF THE SOIL IN THE CUMANACOA LOCALITY, MADE FOR SEISMIC MICROZONATION, 2006

The city of Cumanacoa is considered an historical patrimony of the northeastern region of Venezuela, which in spite of its relative distance (From where?), can be stricken by an earthquake originated in the fault zone of El Pilar. Using the technique of Nakamura (Horizontal/Vertical) it was determined that the locality has fundamental periods between 0.4 and 1 s, with amplifications between 2 and 5.5. The vulnerability index is commonly smaller than 18, which turns it into a relatively safe region for amplifications in important buildings. The critical number of cycles was always larger than 400, which certifies the conditions of all the measures of microtremors. The standardized sedimentary thickness shows a brief cortical structure which is dominated (60%) by areas with half the thickness of the deepest sediment; this affects an area close to 40% of the studied surface. The spatial distribution shows the expected correlation between the fundamental period and the thickness, with a well-defined area of increased sedimentary thickness towards the Centre of the town. The amplification displays a different space distribution demonstrating a possible orientation NNE-SSO. The vulnerability index presents its highest values towards the periphery of the town, specially in the South Central area