Icequakes around Syowa Station, Antarctica

• Main Authors: Katsutada KAMINUMA, Toshio HANEDA
• Format: Article in Journal/Newspaper
• Language: English
• Published: National Institute of Polar Research 1979
• Subjects: geo; Antarctic; Austral; Syowa Station; Antarc*; Antarctica; Ice Sheet; Iceberg*
• Online Access: https://doi.org/10.15094/00008064; https://doaj.org/article/95e0676ee672430a8468bcacb81acd66

Three types of icequakes were observed by the tripartite seismological network at Japanese Antarctic station, Syowa during the period from February 1976 to January 1977. The types are (1) shocks with a sharp initial phase (named Type I), (2) shocks with a small or unidentified amplitude of initial phase (named Type II), and (3) swarms. More than 80000 shocks of Type I and about 80 of Type II occurred through the year. A large number of shocks of Type I occurred in the austral winter season, whereas the number of Type II shocks was larger in summer than in winter. No correlations are identified between the icequake occurrence and the air temperature change, and between that and the sea level change. The features of icequakes suggest that the shocks of Type II are caused by fractures in the ice near the shelf edge of ice sheet, giving rise to the calving of icebergs and so on. Swarms are estimated to be caused by the temperature changes.