Characteristics of Seismic Wave Propagation of Harmonic Tremors Observed at the Margin in the Lützow-Holm Bay, East Antarctica

• Main Author: Kanao, Masaki
• Format: Book Part
• Language: English
• Published: IntechOpen 2017
• Subjects: Science / Earth Sciences / Geology; bisacsh:SCI031000; Antarctic; East Antarctica; Lützow-Holm Bay; Southern Ocean; Syowa Station; The Antarctic; Antarc*; Antarctica; Iceberg*; Sea ice
• Online Access: https://openresearchlibrary.org/viewer/b2adf062-a5a0-4fcb-9d0f-a7ff292cdc65; https://openresearchlibrary.org/ext/api/media/b2adf062-a5a0-4fcb-9d0f-a7ff292cdc65/assets/external_content.pdf; https://doi.org/10.5772/66090

Several kinds of seismic signals involving physical interactions within the shallow atmosphere—ocean—cryosphere—solid earth system have been detected in continental margins of Antarctica and surrounding Southern Ocean. In this study, characteristic features of seismic tremors with harmonic overtones recorded at Syowa Station, the Lützow-Holm Bay (LHB), East Antarctica, are demonstrated for the period from October 2014 to March 2015. A few tens of tremors (N = 81) are identified in both the short-period and broadband seismographs. The characteristic tremors with harmonic overtones can be explained by a repetitive source, suggesting the existence of several interglacial asperities. It implies that the tremors might be involved in local origins, presumably be the dynamics of cryosphere, including discharge of sea-ices from bay, collision of icebergs and fast-ices, calving of glaciers, and the other origins. The strong harmonic tremors with frequency overtones found in LHB are mostly generated by collisions between icebergs and the edge of fast sea-ice by comparison with satellite data. Seismic tremors in terms of cryosphere dynamics, therefore, are likely to be associated with variation of surface environment in the Antarctic, and continuous monitoring of their time-space variability provides indirect evidence of climate change.