DETERMINACIÓN DE MICROZONAS SÍSMICAS PRELIMINARES DEL ÁREA METROPOLITANA DE MÉRIDA
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Universidad Industrial de Santander
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Para contribuir con la microzonificación sísmica del área metropolitana de Mérida se realiza una caracterización geofísica del suelo, aplicando métodos de ruido sísmico ambiental, gravimetría y sísmica de refracción, entre otros. A partir de la técnica de ruido sísmico ambiental se obtienen periodos fundamentales que oscilan entre 0,2 y 2 segundos, los cuales presentan una buena correlación con los espesores de los sedimentos, obtenidos a partir de la gravimetría, y cuyos valores varían entre 12 y 130 m. La sísmica de refracción, a través de 62 perfiles sísmicos, establece modelos de velocidades tanto para las ondas P como para las ondas S de las capas más superficiales, hasta una profundidad máxima de 15 m. Todos estos resultados sirven de base para elaborar el mapa preliminar de microzonas sísmicas que clasifica el área metropolitana en tres partes: la zona 1-1 representada por velocidades de ondas de corte (Vs) desde 350 hasta 650 m/s y espesores de sedimentos entre 0 y 60 m; la zona 1-2 con velocidades Vs desde 350 hasta 650 m/s y espesores de sedimentos de más de 60 m y la zona 2-1 con velocidades Vs iguales ó mayores a 650 m/s y con espesores de sedimentos de 0 a 60 m.
To contribute to the seismic microzonation of the Mérida metropolitan area, a geophysical characterization of the soil, applying methods of ambient seismic noise, gravity and seismic refraction, is performed. From the ambient seismic noise technique, fundamental periods ranging from 0.2 to 2 seconds are obtained, which have good correlation with the sediments thicknesses, obtained from gravimetry, that shows values ranging between 12 and 130 m. The seismic refraction, through 62 seismic profiles, establishes velocity models for the shallow layers up to a maximum depth of 15 m for both P and S waves. All these results provide a basis for a preliminary microzonation map that classifies the metropolitan area into three parts: the zone 1-1 with shear wave velocities from 350 to 650 m/s and sediments thicknesses between 0 and 60 m, the zone 1-2 with shear wave velocities from 350 to 650 m/s and sediments thicknesses greater than 60 m, and the area 2-1 with shear wave velocities equal to or greater than 650 m/s and sediments thicknesses between 0 and 60 m.
To contribute to the seismic microzonation of the Mérida metropolitan area, a geophysical characterization of the soil, applying methods of ambient seismic noise, gravity and seismic refraction, is performed. From the ambient seismic noise technique, fundamental periods ranging from 0.2 to 2 seconds are obtained, which have good correlation with the sediments thicknesses, obtained from gravimetry, that shows values ranging between 12 and 130 m. The seismic refraction, through 62 seismic profiles, establishes velocity models for the shallow layers up to a maximum depth of 15 m for both P and S waves. All these results provide a basis for a preliminary microzonation map that classifies the metropolitan area into three parts: the zone 1-1 with shear wave velocities from 350 to 650 m/s and sediments thicknesses between 0 and 60 m, the zone 1-2 with shear wave velocities from 350 to 650 m/s and sediments thicknesses greater than 60 m, and the area 2-1 with shear wave velocities equal to or greater than 650 m/s and sediments thicknesses between 0 and 60 m.
Keywords
seismic noise, gravity, microzones, Mérida, sísmica, ruido ambiental, gravimetría, microzonas, Mérida