In more recent studies of seismic surface-wave attenuation, I have tried to relate regional variations of Q to the occurrence of tectonic activity. The models, at frequencies between about 0.02 and 0.2 Hz, show generally show high Q throughout the crust in regions that are stable and are not being heated by intrusive activity at depth; a low-Q upper crust and high-Q lower crust in active regions that are in extension; and low Q throughout the entire crust and upper mantle in regions of continental convergence or where major upper mantle heating occurs.

Al-Khatib, H.H., and B.J. Mitchell, Upper mantle anelasticity and tectonic evolution of the western United States from surface wave attenuation, J. Geophys. Res., 96, 18129-18146, 1991.

Seber, D., and B.J. Mitchell, Attenuation of surface waves across the Arabian peninsula, Tectonophysics, 204, 137-150, 1992.

Mitchell, B.J., J. Xie, and W.J. Lin, Attenuation of multiphase surface waves in the Basin and Range province, part II: The fundamental mode, Seism. Res. Lttrs., 64, 239-249, 1993.

Mitchell, B.J., and J. Xie, Attenuation of multiphase surface waves in the Basin and Range province, part III: Inversion for crustal anelasticity, Geophys. J. Int., 116, 468-484, 1994.

Mitchell, B.J., Anelastic structure and evolution of the continents from seismic surface wave attenuation, Rev. Geophys., 33, 441-462, 1995.

Cong, L., and B.J. Mitchell, Seismic velocity and attenuation structure in the Middle East from surface waves, in Q of the Earth: Global, regional, and laboratory studies, edited by B.J. Mitchell, and B. Romanowicz, in press, 1999.