| Summary: | The study of the stresses in the Scotia Arc, determined by right dihedra diagrams of earthquake focal mechanisms, illustrates the present-day tectonics of the region. The Scotia Arc is a large sinistral fault zone, with NE-SWsubhorizontal (or where the relative motion between the Antarctic and South America plates is distributed. While the North Scotia Ridge is deformed by sinistral transpressive faults, related to the general stress field, the transpressive sinistral deformations in the Shackleton Fracture Zone are related to a stress field cj, o f WNW-ESE trend and subhorizontal. In the Bransfield Strait and in the South Scotia Ridge, stresses are extensional, with ef, subvertical and er3 trending NW-SE, and produce respectively in each region, normal and transtensive sinistral faults.
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