Seismicity Associated with Flow of Antarctic Glaciers

We report on local and regional seismicity in the Transantarctic Mountains. The TAMSEIS (Transantarctic Mountains Seismic Experiment, 2000-2003) data were analyzed for source locations using P-wave arrivals. TAMSEIS consisted of 43 portable broadband seismographs deployed across the Trans-Antarctic Mountains and East Antarctica during 2001-2003. Large numbers of events, approximately 50 per day, were detected. The events cluster in the areas of the David Glacier and Drygalski Ice Tongue to the North and Darwin Glacier and Byrd Glacier to the South, with little activity in between. In addition to the greater seismicity of these two regions relative to the rest of the mountain chain, there also appears to be regularity in the timing of the more northerly seismic events at David Glacier. The events are neither uniformly distributed nor Poisson-distributed in time, but occur in isolated, concentrated bursts. The spacing between bursts is approximately one half day; we investigate hypotheses of daily periodicity vs. tidal periodicities. We hypothesize that the events are related to the motion of these outlet glaciers. These glaciers drain a significant portion of the interior East Antarctic Ice Sheet and are particularly important because of the relatively low flux of ice through the mountains in between (where the Dry Valleys are situated).