Effective discrimination of icequakes on seismic records from Mawson station

Abstract

The telemetered seismic station at Mawson, Antarctica, was one of the primary Australian stations participating in the Group of Scientific Experts Technical Test (GSETT) experiment to test an international seismic monitoring system. Mawson signals are continuously transmitted to the National Data Center (NDC) in Canberra and also forwarded to the International Data Centre (IDC) in Washington, where further event analysis is performed. Numerous seismic signals are recorded on seismograms from the Mawson station, with a likely mechanism of sudden fracturing of ice. The aim of this study was to find a procedure which will effectively discriminate seismic signals from these icequakes and thus speed up the analysis of the other detected events. An automatic algorithm was designed to identify icequakes according to their characteristics: frequency content, duration, azimuth, inclination and magnitude. The program was tested on a few datasets of randomly selected periods and one comprised of records of nuclear explosions detonated in the period of 1995/96. The preliminary results showed that this method was capable of distinguishing icequakes and could substantially improve the production of an automated event list.