On the response of the ocean lithosphere to sea-mount loads from Geos 3 satellite radar altimeter observations

Short wavelength anomalies in the geoid, derived from Geos 3 satellite radar altimeter data, have been investigated in the southern Indian Ocean and in French Polynesia. A number of these anomalies, associated with sea-mounts or volcanic islands, can be explained by regional isostatic compensation models, yielding estimates of the flexural rigidity and the effective elastic thickness H of the oceanic lithosphere. This thickness appears to be about one third of the seismic estimates for this thickness. The H also indicates some age dependence, compatible with the √age models of the thermal lithosphere. These results are in agreement with the results of previous studies on the flexure of the lithosphere.