Gravity study of the Pitcairn-Easter hotline

Marcia Maia (1) , G.. A. Dehghani (2) , M Diament (3) , J Francheteau (1) , P Stoffers (4)

1 Laboratoire de Géophysique
2 Institut für Geophysik [Hamburg]
3 Laboratoire de Gravimétrie et Géodynamique, UMR 7577
4 Geologisch-Paläontologisches Institut

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 N65øE, 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.

Domains: Sciences of the Universe [physics]

Marcia Maia, G.. A. Dehghani, M Diament, J Francheteau, P Stoffers. Gravity study of the Pitcairn-Easter hotline. Geophysical Research Letters, 1994, 21, pp.2527-2530. ⟨insu-01354635⟩