Atenuacion anelástica en la Cordillera central del Océano Atlántico

Abstract

The attenuation of the Rayleigh wave fundamental mode along a stripe of 220 km from the sides of the Mid-Atlantic Ridge (0-11 m.y.) and adjacent regions (>11m.y.) were obtained using a two-station method. From the estimated attenuation coefficients and group velocities of both regions it was possible to obtain the regionalized quality factors for Rayleigh waves. Applying modem inversion methods to phase and group velocities a velocity model for the shear wave was obtained for the> 11 m.y. old region of the Atlantic Ocean. Similarly, from the attenuation coefficients anelastic models for 0-11m.y. and >11 m.y. regions were developed. In general, the results indicate that the internal friction beneath the Mid-Atlantic Ridge is larger than beneath the adjacent regions and that the variations of anelasticity between isochrones 11 and 23 m.y. of the Mid-Atlantic Ridge are practically negligible. These results are consistent with previous studies carried out at the Atlantic and Pacific Oceans which support the fact that anelastic attenuation is a function of the litospheric age.