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Ross Ice Shelf Micro-Icequakes and Ocean Swell Induced Seismicity

Description: 

Seismological deployments spanning the Ross Ice Shelf (RIS) have provided substantial data to interpret the physical processes taking place across the ice during an era when many Antarctic ice shelves are undergoing mass loss through calving and basal melting processes (Rignot, et al., 2013). Thirty-four broadband seismic stations deployed across the RIS continuously collected data at high-sampling rates (100 and 200 S/s) between 2015-2017 (e.g., Bromirski et al., 2015). Interpretations of these data paired with satellite imagery and other constraints have identified multiple seismogenic phenomena related to rifting, fracture, calving, and flexure of the ice shelf induced by oceanic forcing across tidal, tsunami, infragravity, and ocean swell periods. Wave impacts and fracture near the ice front create micro-icequakes, particularly in the summer when ocean swell (periods of 8 to 30 s) is not attenuated by sea ice in the Ross Sea. For certain three-week periods in the multi-year dataset, stochastically swell-synchronized seismic events are observed to generate swell-harmonic spectral peaks in long-widow-duration spectrograms. Components of this signal have been interpreted as the multistage failure of near-front crevasses that can culminate in calving. We are establishing a catalog of such events spanning the complete RIS/DRIS seismic dataset to further interpret seismogenic phenomena associated with near ice-front fracture and calving, and to better understand temporal and other characteristics using matched filtering, envelope beamforming, and single-station seismic signatures. Additionally, seismicity associated with the cataloged swell-synchronized events will be compared with several ocean state parameters to investigate the hypothesized (Aster et al., 2021) controlling mechanism(s) of the events. The high temporal resolution of these seismic observations may uniquely provide valuable insights into the synchronicity of the compounding inputs which stress the ice shelf and ultimately result in ice mass loss.

Session: Monitoring Climate Change With Seismology [Poster]

Type: Poster

Date: 4/18/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Elisa A. McGhee

Student Presenter: Yes

Invited Presentation: 

Authors