NSFGEO-NERC: Ice-shelf Instability Caused by Active Surface Meltwater Production, Movement, Ponding and Hydrofracture

南极冰架表面和浅层地下融水的演变对其稳定性具有重要意义，2002年拉森B冰架的快速崩塌就证明了这一点。了解冰架稳定性的原因是至关重要的，因为冰架支撑着内陆冰的排出，因此影响着冰盖对海平面上升的贡献。与地表融水运动、积水和排水相关的应力变化可能引发冰架破裂。这些变化可能导致冰架弯曲和断裂。这个为期四年的项目将提供关键的地球物理观测，以提高对冰架融水及其对稳定性的影响的认识。这项工作将在南极半岛的乔治六世冰架上进行，那里每年夏天都会形成数百个表面湖泊。在27个月的时间里，将部署全球定位系统、地震仪、水压传感器、自动气象站和冰内热敏电阻，分别记录冰架挠度、断裂地震活动性、水深、地表和地下融化，地点在乔治六世冰架的几个表面湖泊内和周围，距离英国南极调查局化石布拉夫站大约20公里。现场数据将用于验证和扩展团队的方法，以模拟冰架弯曲和应力，以及可能的“Larsen-B型”冰架不稳定和破裂。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The evolution of surface and shallow subsurface meltwater across Antarctic ice shelves has important implications for their (in)stability, as demonstrated by the 2002 rapid collapse of the Larsen B Ice Shelf. It is vital to understand the causes of ice-shelf (in)stability because ice shelves buttress against the discharge of inland ice and therefore influence ice-sheet contributions to sea-level rise. Ice-shelf break-up may be triggered by stress variations associated with surface meltwater movement, ponding, and drainage. These variations may cause an ice shelf to flex and fracture. This four-year project will provide key geophysical observations to improve understanding of ice-shelf meltwater and its effects on (in)stability. The work will be conducted on the George VI Ice Shelf on the Antarctic Peninsula, where hundreds of surface lakes form each summer. Over a 27-month period, global positioning systems, seismometers, water pressure transducers, automatic weather stations, and in-ice thermistor strings will be deployed to record ice shelf flexure, fracture seismicity, water depths, and surface and subsurface melting, respectively, in and around several surface lakes on the George VI Ice Shelf, within roughly 20 km of the British Antarctic Survey's Fossil Bluff Station. Field data will be used to validate and extend the team's approach to modelling ice-shelf flexure and stress, and possible "Larsen-B style" ice-shelf instability and break-up.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.