Seismicity and tectonics around the northern Antarctic Peninsula from King Sejong station data

Abstract

Local earthquakes recorded at the King Sejong station (62 degrees 13'31"S, 58 degrees 17'07"W) from 1995-96 have been analysed to study the seismicity and tectonics around the northern Antarctic Peninsula. The nature of shallow-focused normal fault earthquakes along the South Shetland Platform is still unclear. Dominant normal fault earthquakes and minor strike-slip earthquakes in the Eastern Bransfield Basin suggest 1) ongoing extension, and 2) transtensional stress transmitted from the Antarctic-Scotia transform boundaries, the South Scotia Ridge and the Shackleton Fracture Zone. A lack of seismicity in the Central Bransfield Basin supports that active seismicity in the Eastern Bransfield Basin is not a result of subduction along the South Shetland Trench. Shallow focused earthquakes have been observed along the NW-SE trending gravity low line between the Central and the Eastern Bransfield Basins that approximately coincides with the landward projection of a fracture zone in the former Phoenix Plate.