Overview of the 250 autonomous seismological stations (Fairfield nodes) deployed during the Icewaveguide project in Svalbard (Norway)

The sea ice is disappearing with global warming, and if the trend is clear over the last few decades, scientists are still wondering about the speed of this disappearance, which seems much greater than the models predict. To better assess the quality of the polar ice (its thickness, its degree of fracturing), a team of scientists from ISTerre led by Ludovic Moreau is conducting a reconnaissance and test expedition in February and March 2019. The objective: to listen to the natural vibrations of the ice pack in order to deduce its mechanical characteristics (thickness, solidity, etc.). A pilot site has been identified in Svalbard, at 78° north latitude, as close as possible to the Arctic pack ice. 250 seismic sensors (seismometers) from the Sismob mobile instrument park of Resif were installed there for one month to record the vibrations and murmurs of this small ephemeral ice pack (it forms only a few months a year) in the Sveagruva fjord. This picture shows all the 250 autonomous seismological stations, Fairfield nodes, deployed on the frozen lake of Vallunden. The orange masts were used to delimit the perimeter to be studied. Sismob is part of Resif, a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. Resif is based on observation networks of high technological level, composed of seismological, geodetic and gravimetric instruments deployed in a dense manner throughout the French territory. The data collected allow to study with a high spatio-temporal resolution the ground deformation, the superficial and deep structures, the seismicity at the local and global scale and the natural hazards, especially seismic, on the French territory. Resif integrates with European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the interior of the Earth as a whole and to study many natural phenomena.