Antarctic Seismic Array Detects 245 Glacial Quakes at Thwaites Terminus 2010–2023

The study deployed regional seismic arrays rather than relying on the global network that missed smaller-magnitude Antarctic events. Events lack high-frequency body waves typical of tectonic quakes and instead show the long-period signals produced when tall, thin icebergs capsize and strike the glacier front. Two-thirds of detections occurred at Thwaites, with a secondary cluster at Pine Island, both marine-terminating glaciers already responsible for the largest Antarctic contributions to sea-level rise.

Timing diverges from Greenland’s summer peak driven by surface melt. Instead, peak activity at Thwaites aligns with satellite-observed ice-tongue speedup attributed to warmer Circumpolar Deep Water intrusion, underscoring ocean forcing as the dominant short-term control. This matches independent oceanographic moorings and modeling showing basal melt rates rising when modified Circumpolar Deep Water reaches the cavity.

The work fills a detection gap but remains limited by sparse station coverage and lack of direct visual confirmation of individual calving events. Expanded broadband arrays plus repeat high-resolution satellite imagery of the terminus would allow magnitude calibration and direct linkage of individual quakes to iceberg dimensions and ocean temperature anomalies.

Continued monitoring is essential because Thwaites holds enough ice to raise global sea level by three meters if fully destabilized, and the newly detected seismicity provides an in-situ indicator of mechanical instability that satellite altimetry alone cannot resolve at daily timescales.