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

南极冰架上表层和浅层次表层融化水的演变对其稳定性有重要影响，2002年拉森B冰架的快速坍塌就证明了这一点。理解冰架稳定的原因至关重要，因为冰架支撑着内陆冰的排放，从而影响到冰盖对海平面上升的贡献。冰架的破裂可能是由与地表融水运动、积水和排水有关的应力变化引起的。这些变化可能会导致冰架弯曲和破裂。这个为期四年的项目将提供关键的地球物理观测，以增进对冰架融水及其对稳定性的影响的了解。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水面湖泊。在27个月的时间里，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串将被部署，分别在乔治六世冰架上的几个表层湖泊及其周围记录冰架弯曲、破裂地震活动、水深以及表层和次表层融化，距离英国南极调查局的化石悬崖站约20公里。现场数据将被用来验证和扩展团队对冰架弯曲和应力以及可能的“Larsen-B式”冰架不稳定和破裂进行建模的方法。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.