Characteristics of non-tectonic tremors around the Lützow-Holm Bay, East Antarctica, during 2013–2015

• Published in: Polar Science
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Cryosphere; Fast-sea-ice; Harmonic tremor; Microbaroms; MODIS; East Antarctica; Austral; Lützow-Holm Bay; Antarc*; Antarctica; Polar Science; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=15603; http://id.nii.ac.jp/1291/00015498/

Characteristics of non-tectonic tremors, excited mainly by the interaction within the cryosphere, were investigated using seismic waveform data of 2013–2015 recorded at broadband stations on the east coast of the Lützow-Holm Bay (LHB), East Antarctica. The tremors were classified into three types by spectral and waveform features. Type A events have long durations, typically several hours to days, with high amplitudes of spectra over 1–8 Hz. They occur dominantly in austral summers. Type B events have characteristically irregular variations in discrete dominant frequencies in spectra. Type C events are harmonic tremors with discrete dominant frequencies in spectra that vary regularly with time. Type B and C events show similar seasonal variations: they are numerous around April and less so in austral winter. Comparison of spectra between seismic waves and infrasound, together with satellite images, suggests that type A events originated from storm-induced swells near off-LHB. Source locations of type C events and satellite images suggest that type C events are likely to result from the collision/crevassing of ice blocks in fast-sea-ice in LHB. Similar seasonal variations of type B and C events imply that these two events have similar origins.