Gravity study of the Pitcairn‐Easter Hotline

Abstract

Shipboard free air gravity and bathymetric anomalies with an extension of 400 km were identified across the Pitcairn‐Easter hotline in the South Pacific. The anomalies are associated with one of the positive geoid undulations observed in the area from satellite data. Several smaller topographic features, volcano‐tectonic ridges oriented N65°E, are superimposed on the topographic high. Admittance computations and direct modeling show that the swell topography is compensated by a low density zone within the lithosphere, 4 to 8 km below the crust The volcano tectonic ridges are locally compensated in a classical Airy sense. The swell and the associated ridges were probably created by the action of a thermal anomaly resulting from the interaction of the Easter Island hotspot and of the Easter Microplate accretion centers. Copyright 1994 by the American Geophysical Union.