abstract
A P-wave velocity profile for the upper mantle at depths between 200 and 800 km beneath Eastern United States has been constructed from a combination of data from natural and artificial sources. Data for this part of the upper mantle are scarce, particularly beyond 20° epicentral distance, because of the sparse distribution of relevant sources and stations. Nevertheless, this study is the first to use amplitude constraints in a model determination for this region, and the model that has been chosen can account for the main observed amplitude features as well as travel times. The resulting velocity profile is similar to those previously determined for the regions to the north and west, but has a broadening of velocity transitions relative to those in the western United States. Evidence is found for the existence of lateral velocity inhomogeneity within the mantle.
P-Wave Velocity Structure in the Upper Mantle beneath the Japanese Islands