ANALYZING TAMSEIS DATA FOR SEISMIC EVENTS OF HIGH TEMPORAL REGULARITY AND LARGE MAGNITUDE (Mw=1.8) BENEATH DAVID GLACIER, AND FOR LONG-PERIOD PLATE-MARGIN EVENTS

Open Access
Author:
Zoet, Lucas Keith
Graduate Program:
Geosciences
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 13, 2009
Committee Members:
  • Sridhar Anandakrishnan, Thesis Advisor
Keywords:
  • ice quake
  • TAMSEIS
  • Seismic
  • Antarctica
Abstract:
Highly regular seismicity associated with the flow of David Glacier in the Transantarctic Mountains of Antarctica has been detected and analyzed. We used data from the TAMSEIS network which consisted of 42 broadband seismometers deployed from November 2000 through December 2003. The seismic events recur at a regular time interval of approximately 20 min. Travel times suggest that the events originated from the base of the David Glacier (approximately 1.8 km deep in this area). are consistent with low-angle reverse faulting P-wave first motions. A fault strike of 185 degrees was calculated, which is normal to the flow of David Glacier. The events are likely caused by an asperity beneath David Glacier that regularly released stress, that accumulated as David Glacier flowed over the asperity. The regularity of the events is due to the constant and homogenous driving stress of the overlying ice as well as the weakness of the bed. Models of earthquake source regions that include a few asperities within a weak active fault are though to display similar behavior. The TAMSEIS network has also been used to analyze long period seismic events occurring around the Antarctic plate. Twenty one events have been located that previously had not been catalogued in the National Earthquake Information Center’s catalog. Mostly originating from the plate boundaries.