The Origin of Double-Frequency Microseism and Its Seasonal Variability at King Sejong Station, Antarctica

Abstract

Korea Polar Research Institute has been operating a broadband seismic station (KSJ1) at the King George Island (KGI), Antarctica, since 2001. Examining ambient seismic noise levels using power spectral analysis for the period of 2006–2008 at the KSJ1, we observed a seasonal pattern at a 4–10 s period. The amplitude of double-frequency (DF) microseism reaches a peak in May. Correlation of the DF energy and its predominant period with significant ocean-wave height and peak wave period models from the WAVEWATCH III and polarization analysis consistently indicate that ocean swell in the Drake Passage is a possible source to excite the DF microseism at the KGI. We also found that the temporal variation of DF amplitude is coincident with the seasonal change of ocean-acoustic ambient noise level around the KGI, which implies that incorporating long-term seismic and hydroacoustic noise information might give us an opportunity to figure out the characteristics of local climate variation near the Antarctic Peninsula.