Peculiarities of mantle waves from long-range profiles

Long-range seismic experiments carried out in different regions of the USSR show strong variations of the mantle wave velocities and attenuation. Relatively high mantle velocities, more than 8.2–8.3 km/s, are observed in the old platform areas. To exclude the crustal influence on the mantle waves and to separate the vertical and horizontal inhomogeneity effect the relations between the overlapping travel-time curves are analyzed. As a result, a mantle stratification with positive average velocity gradient in the strata is revealed up to depths of 200 km. Local inclusions with very high (more than 8.5 km/s) and relatively low (less 8.0 km/s) velocities are typical of the mantle.           ARK: https://n2t.net/ark:/88439/y090547 Permalink: https://geophysicsjournal.com/article/261 &nbsp