Observations of flexure and the state of stress in the oceanic lithosphere

Observations of flexure indicate the effective elastic thickness of the oceanic lithosphere is 2 to 3 times smaller than the seismic or thermal thickness of oceanic lithosphere. The effective elastic thickness is a function of temperature and hence age of the lithosphere at the time of loading. Recent results of experimental rock mechanics indicate that the strength of rocks is a strong function of temperature and that the oceanic lithosphere responds to loading by thinning rapidly from its seismic thickness to its rheologic thickness. We have used a yield stress envelope based on experimental rock mechanics to estimate the maximum bending stresses associated with the load of the Hawaiian Islands near Oahu. These results indicate that the oceanic lithosphere is capable of supporting stresses of at least 1 kbar for long periods of geological time (>50 m.y.).