<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Carr, Chris G.</style></author><author><style face="normal" font="default" size="100%">Carmichael, Joshua D.</style></author><author><style face="normal" font="default" size="100%">Pettit, Erin C.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Wintertime brine discharge at the surface of a cold polar glacier and the unexpected absence of associated seismicity</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Earth Surface</style></secondary-title><short-title><style face="normal" font="default" size="100%">JGR Earth Surface</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">crevasses</style></keyword><keyword><style  face="normal" font="default" size="100%">cryoseismology</style></keyword><keyword><style  face="normal" font="default" size="100%">glacier hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">Rayleigh waves</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2022</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://onlinelibrary.wiley.com/doi/10.1029/2021JF006325</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">127</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;A subglacial groundwater system beneath Taylor Glacier, Antarctica, 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. Identifying which fracture processes are observed seismically can help us better characterize the hydrological system at Taylor Glacier, and more generally, provide us with a broader understanding of englacial hydrologic activity in cold glaciers. We document wintertime brine discharge using time-lapse photography. Subfreezing air temperatures during the brine discharge indicate that surface melt-induced hydrofracture is an unlikely trigger for brine release. 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.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Carr, Chris G.</style></author><author><style face="normal" font="default" size="100%">Carmichael, J. D.</style></author><author><style face="normal" font="default" size="100%">Pettit, Erin C.</style></author><author><style face="normal" font="default" size="100%">Truffer, Martin</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The influence of environmental microseismicity on detection and interpretation of small-magnitude events in a polar glacier setting</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Glaciology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">07/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.cambridge.org/core/journals/journal-of-glaciology/article/influence-of-environmental-microseismicity-on-detection-and-interpretation-of-smallmagnitude-events-in-a-polar-glacier-setting/E1A441425341F677117509351F3C6763</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Glacial environments exhibit temporally variable microseismicity. To investigate how microseismicity influences event detection, we implement two noise-adaptive digital power detectors to process seismic data from Taylor Glacier, Antarctica. We add scaled icequake waveforms to the original data stream, run detectors on the hybrid data stream to estimate reliable detection magnitudes and compare analytical magnitudes predicted from an ice crack source model. We find that detection capability is influenced by environmental microseismicity for seismic events with source size comparable to thermal penetration depths. When event counts and minimum detectable event sizes change in the same direction (i.e. increase in event counts and minimum detectable event size), we interpret measured seismicity changes as &amp;lsquo;true&amp;rsquo; seismicity changes rather than as changes in detection. Generally, one detector (two degree of freedom (2dof)) outperforms the other: it identifies more events, a more prominent summertime diurnal signal and maintains a higher detection capability. We conclude that real physical processes are responsible for the summertime diurnal inter-detector difference. One detector (3dof) identifies this process as environmental microseismicity; the other detector (2dof) identifies it as elevated waveform activity. Our analysis provides an example for minimizing detection biases and estimating source sizes when interpreting temporal seismicity patterns to better infer glacial seismogenic processes.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">Jill A. Mikucki</style></author><author><style face="normal" font="default" size="100%">German, Laura A.</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">Sue Welch</style></author><author><style face="normal" font="default" size="100%">Christopher B. Gardner</style></author><author><style face="normal" font="default" size="100%">Tulaczyk, Slawek M.</style></author><author><style face="normal" font="default" size="100%">Pettit, Erin C.</style></author><author><style face="normal" font="default" size="100%">Kowalski, Julia</style></author><author><style face="normal" font="default" size="100%">Dachwald, Bernd</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The Geochemistry of Englacial Brine From Taylor Glacier, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Biogeosciences</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2019</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JG004411</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">124</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Blood Falls is a hypersaline, iron‐rich discharge at the terminus of the Taylor Glacier in the McMurdo Dry Valleys, Antarctica. In November 2014, brine in a conduit within the glacier was penetrated and sampled using clean‐entry techniques and a thermoelectric melting probe called the IceMole. We analyzed the englacial brine sample for filterable iron (fFe), total Fe, major cations and anions, nutrients, organic carbon, and perchlorate. In addition, aliquots were analyzed for minor and trace elements and isotopes including δD and δ&lt;sup&gt;18&lt;/sup&gt;O of water, δ&lt;sup&gt;34&lt;/sup&gt;S and δ&lt;sup&gt;18&lt;/sup&gt;O of sulfate, &lt;sup&gt;234&lt;/sup&gt;U, &lt;sup&gt;238&lt;/sup&gt;U, δ&lt;sup&gt;11&lt;/sup&gt;B, &lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr, and δ&lt;sup&gt;81&lt;/sup&gt;Br. These measurements were made in order to (1) determine the source and geochemical evolution of the brine and (2) compare the chemistry of the brine to that of nearby hypersaline lake waters and previous supraglacially sampled collections of Blood Falls outflow that were interpreted as end‐member brines. The englacial brine had higher Cl&amp;minus; concentrations than the Blood Falls end‐member outflow; however, other constituents were similar. The isotope data indicate that the water in the brine is derived from glacier melt. The H&lt;sub&gt;4&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt; concentrations and U and Sr isotope suggest a high degree of chemical weathering products. The brine has a low N:P ratio of ~7.2 with most of the dissolved inorganic nitrogen in the form of NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;. Dissolved organic carbon concentrations are similar to end‐member outflow values. Our results provide strong evidence that the original source of solutes in the brine was ancient seawater, which has been modified with the addition of chemical weathering products.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue></record></records></xml>