Accession Number:

ADA199131

Title:

Influence of Scattering on Seismic Waves: Velocity and Attenuation of the Upper Crust in Southeast Maine

Descriptive Note:

Scientific rept. no. 3, 1 Feb-31 Jul 1987

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE EARTH RESOURCES LAB

Report Date:

1988-03-21

Pagination or Media Count:

58.0

Abstract:

Rg and Pg velocities and Rg attenuation have been examined for the Central Merrimack Synclinorium and nearby regions in southeastern Maine using digital records from a seismic refraction experiment. Determination of Rg group velocities and Pg travel times indicates that both lateral variations and azimuthal anisotropy are present in the study area. The axes of the axes of the azimuthal velocity anisotropy appear to lie along and perpendicular to the Appalachian structural strike in the region, with Rg group velocities along strike up to 20 faster than cross strike velocities. Measurement of Rg attenuation gives Q values of 25-80, varying with frequency. Inversion of the Rg group velocity for velocity structure shows that both the compressional and shear velocities increase rapidly with depth in the upper 1 km in the region. Keywords Short period Rayleigh waves, Anisotropy, Earth crustal structure, Seismic wave attenuation, New England.

Subject Categories:

  • Seismology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE