OBSERVATIONAL CONSTRAINTS ON MODELS OF THE HAWAIIAN HOT-SPOT SWELL

A detailed analysis of the topography and geoid associated with the Ha waii-Emperor seamount chain reveals that while geoid/topography ratios are high over the southeastern part of the chain, they fall off with distance away from the current hot spot location. The topographic expr ession of the swell has two maxima near the intersections between the seamount chain and the Murray and Molokai fracture zones, respectively . Both geoid and topography rapidly decrease westward of the intersect ion with the Murray fracture zone. It appears that the region of the P acific plate between the two fracture zones has been more susceptible to reheating and hot spot penetration than elsewhere along the chain. Alternatively, the observed pattern may be indicative of time variatio n in the strength of the Hawaiian hot spot.