TY - JOUR T1 - Analysis of a GRACE global mascon solution for Gulf of Alaska glaciers JF - Journal of Glaciology Y1 - 2013 A1 - Anthony A. Arendt A1 - Scott B Luthcke A1 - Alex S. Gardner A1 - Shad OʼNeel A1 - D. Hill A1 - Geir Moholdt A1 - Waleed Abdalati VL - 59 IS - 217 ER - TY - JOUR T1 - Does calving matter? Evidence for significant submarine melt JF - Earth and Planetary Science Letters Y1 - 2013 A1 - Timothy C. Bartholomaus A1 - Chris F. Larsen A1 - Shad OʼNeel VL - 380 UR - http://www.sciencedirect.com/science/article/pii/S0012821X13004408 ER - TY - JOUR T1 - Calving seismicity from iceberg–sea surface interactions JF - Journal of Geophysical Research Y1 - 2012 A1 - Timothy C. Bartholomaus A1 - Chris F. Larsen A1 - Shad OʼNeel A1 - West, M. VL - 117 ER - TY - JOUR T1 - Using surface velocities to calculate ice thickness and bed topography: a case study at Columbia Glacier, Alaska, USA JF - Journal of Glaciology Y1 - 2012 A1 - R  W McNabb A1 - Regine Hock A1 - Shad OʼNeel A1 - L  A Rasmussen A1 - Ahn, Y. A1 - M Braun A1 - H Conway A1 - Herreid, S. A1 - Ian Joughin A1 - W. Tad Pfeffer A1 - B  E Smith A1 - Martin Truffer VL - 58 IS - 212 ER - TY - JOUR T1 - A complex relationship between calving glaciers and climate JF - Eos, Transactions American Geophysical Union Y1 - 2011 A1 - Post, Austin A1 - Shad OʼNeel A1 - Roman J. Motyka A1 - Streveler, Gregory KW - climate KW - glaciers AB - Many terrestrial glaciers are sensitive indicators of past and present climate change as atmospheric temperature and snowfall modulate glacier volume. However, climate interpretations based on glacier behavior require careful selection of representative glaciers, as was recently pointed out for surging and debris-covered glaciers, whose behavior often defies regional glacier response to climate [Yde and Paasche, 2010]. Tidewater calving glaciers (TWGs)—mountain glaciers whose termini reach the sea and are generally grounded on the seafloor—also fall into the category of non-representative glaciers because the regional-scale asynchronous behavior of these glaciers clouds their complex relationship with climate. TWGs span the globe; they can be found both fringing ice sheets and in high-latitude regions of each hemisphere. TWGs are known to exhibit cyclic behavior, characterized by slow advance and rapid, unstable retreat, largely independent of short-term climate forcing. This so-called TWG cycle, first described by Post [1975], provides a solid foundation upon which modern investigations of TWG stability are built. Scientific understanding has developed rapidly as a result of the initial recognition of their asynchronous cyclicity, rendering greater insight into the hierarchy of processes controlling regional behavior. This has improved the descriptions of the strong dynamic feedbacks present during retreat, the role of the ocean in TWG dynamics, and the similarities and differences between TWG and ice sheet outlet glaciers that can often support floating tongues. VL - 92 UR - http://dx.doi.org/10.1029/2011EO370001 ER - TY - JOUR T1 - Glacier microseismicity JF - Geology Y1 - 2010 A1 - West, M. A1 - Chris F. Larsen A1 - Martin Truffer A1 - Shad OʼNeel A1 - LeBlanc, Laura AB - We present a framework for interpreting small glacier seismic events based on data collected near the center of Bering Glacier, Alaska, in spring 2007. We find extremely high microseismicity rates (as many as tens of events per minute) occurring largely within a few kilometers of the receivers. A high-frequency class of seismicity is distinguished by dominant frequencies of 20–35 Hz and impulsive arrivals. A low-frequency class has dominant frequencies of 6–15 Hz, emergent onsets, and longer, more monotonic codas. A bimodal distribution of 160,000 seismic events over two months demonstrates that the classes represent two distinct populations. This is further supported by the presence of hybrid waveforms that contain elements of both event types. The high-low-hybrid paradigm is well established in volcano seismology and is demonstrated by a comparison to earthquakes from Augustine Volcano. We build on these parallels to suggest that fluid-induced resonance is likely responsible for the low-frequency glacier events and that the hybrid glacier events may be caused by the rush of water into newly opening pathways. VL - 38 UR - http://geology.gsapubs.org/content/38/4/319.abstract ER - TY - JOUR T1 - Iceberg calving as a primary source of regional-scale glacier-generated seismicity in the St. Elias Mountains, Alaska JF - Journal of Geophysical Research Y1 - 2010 A1 - Shad OʼNeel A1 - Chris F. Larsen A1 - Rupert, N. A1 - Hansen, R. VL - 115 ER -