University of California Santa Cruz
Santa Cruz, California
Supporting Stations: McMurdo Station
Research Locations: Subglacial Lake Whillans
A component of WISSARD, this project focuses on deployment of a surface passive seismic network and an array of borehole seismometers on Whillans Ice Stream (WIS), in the vicinity of Subglacial Lake Whillans (SLW). The seismic data will help to reveal the role of subglacial hydrology in controlling temporal variability of ice stream dynamics and mass balance. Specifically, borehole seismology will allow basal earthquakes and seismic signals generated by subglacial hydrology to be recorded and studied that are orders of magnitude smaller and have a more complete frequency content than possible using surface instrumentation alone. Determination of the source characteristics of basal events will permit the role of small asperities or ‘sticky spots’ in controlling basal motion to be assessed. The study area experiences large changes in ice velocity in response to tidally triggered stick-slip cycles of WIS and periodic filling and draining of SLW, allowing the characteristics of basal motion during fast and slow ice movement and subglacial lake inflow, outflow, and quiescence to be compared.
Field Season Overview:
Due to repercussions from the government shutdown the WISSARD Hot Water Drill campaign at the Grounding Zone has been deferred. However, a combined field team of 7-8 participants from Schwartz (C-525-M) and Tulaczyk (C-521-M/0839142) will deploy to SLW/CReSIS camp via LC-130 in mid December and will exist as their own self-supported mobile field team focusing on multiple geophysical installations accessed via snowmobile in the Whillans Ice Stream area. In early January the combined C-521/C-525 field team will rendezvous at SLW/Cresis with five University of Nebraska Drillers (C-524/C-530) and some supplemental science personnel, who will have arrived via fixed-wing aircraft, and the ASC WISSARD traverse, who will have transported the roving drill and associated camp equipment out to the site. Members of the WISSARD traverse will deliver the team/equipment to Roving Site 1A. As opposed to the original plan, where the WISSARD traverse would not stay with the team and would only provide transportation as required, the plan is now to have the WISSARD traverse stay on site and provide needed support during drilling/science operations. Once operations are completed at Roving Site 1A the traverse team, drillers, and grantees will move as a group to Roving Site 1B, 2A, and 2B respectively. Estimated duration at each site will be approximately three days. The WISSARD traverse will ultimately bring the drillers and science team back to the CReSIS camp at SLW where they will return to McMurdo via fixed wing during the last week of January. The WISSARD traverse will then traverse the roving drill and associated camp equipment back to McMurdo. Refer to the Rack C-530-M RSP for details on the roving drill logistics and the Tulaczyk C-521-M RSP for details related to the shared component of the C-525-M fieldwork.
Deploying Team Members:
Susan Schwartz (PI)