Seismicity and aseismic slip along the Eltanin Fracture Zone ( Pacific-Antarctic Ridge).

The seismic history of the Eltanin Fracture Zone on the Pacific-Antarctic Ridge for the years 1920-81 shows that the seismic slip accumulated during this recording interval accounts for only a small fraction (<10%) of the amount of slip predicted by kinematic models of plate motion. We propose that the remainder of the plate motion along the transform faults making up the Eltanin system occurs as aseismic creep. We interpret the Eltanin Fracture Zone in the light of an 'asperity' model, involving small, well-separated asperities. Its segmented nature and creeplike behavior may be due to the presence of excess magma and, possibly, local upwelling, which could also be involved in the mechanism of generation of the Louisville Ridge.-from Authors