A subglacial groundwater system beneath Taylor Glacier discharges hypersaline, iron-rich brine episodically at the glacier surface to create Blood Falls; however, the triggering mechanism for these brine release events is not yet understood. We document wintertime brine discharge using time-lapse photography to show that the mechanism does not require melt-induced hydrofracture. Further, we analyze local seismic data to test a hypothesis that fracturing generates elevated surface wave energy preceding and/or coinciding with brine release events. Our results show no discernible elevated Rayleigh wave activity prior to or during Blood Falls brine release. Instead, we find a pattern of seismic events dominated by a seasonal signal, with more Rayleigh events occurring in the summer than the winter from the Blood Falls source area. We calculate that the volumetric opening of cracks that would generate Rayleigh waves at our detection limits are of similar size to myriad cracks in glacier ice, lake ice, and frozen sediment in the terminus area. We therefore propose that any fracturing coincident with brine release activity likely consists of a series of smaller opening events that are masked by other seismicity in the local environment.

Temporally variable environmental microseismicity and narrowband signals are both demonstrated to reduce the detectability of small seismic events. We investigate the influence of winter wind events on detection thresholds for a 3-sensor seismic network at the terminus of Taylor Glacier, Antarctica. As wind speeds increase, we observe higher spectral amplitudes across the frequency spectrum; however, some frequency bands are preferentially excited. Surprisingly, these spectral peaks shift frequencies through time. To determine detection thresholds, we implement a waveform injection routine wherein we add scaled waveforms to the datastream, and track changes in the size of the smallest scaled event that we can reliably detect. We thereby demonstrate a capability to quantify the size of the smallest detectable event in temporally variable signal environments. Lastly, we propose a method to forecast our ability to detect sources of a threshold size in measured noise conditions.

Taylor Glacier, located in the McMurdo Dry Valleys of Antarctica has piqued curiosity since the first observations in 1903. Episodic release of iron-rich brine at or near the glacier terminus rapidly oxidizes, forming a visually striking red stain on the ice and glacier forefield called ‘Blood Falls’. The triggering mechanism behind these releases is unknown. The recent history of brine releases have been well documented since the 1993-94 summer season. To better understand the frequency and extent of brine releases over a longer time period we compile a detailed history of observations of the Taylor terminus from photographs, journals, field reports, oral histories, and published papers prior to the onset of more frequent monitoring in the 1990s. We developed a confidence assessment framework for our interpretation of the presence/absence of brine icing deposits. Results show that of the 30 summer seasons between 1903-1904 and 1993-1994 with interpretable observations, 21 seasons (70%) show evidence of brine flow events, and 9 seasons show no evidence of brine flow. At least two of these brine flow events are newly reported by our study. Concurrent observations of the glacier terminus over the same period showed a localized advance and collapse of a small portion of the southern terminus. We demonstrate a framework to fuse multiple data types and qualitatively assess the confidence level of our interpretations that could be applied to similar investigations of environmental history. We encourage other researchers to explore and contribute to the growing collection of open access historical archives.