Icequake-Magnitude Scaling Relationship Along a Rift Within the Ross Ice Shelf, Antarctica

Fractures within ice shelves are zones of weakness, which can deform on timescales from seconds to decades. Icequakes produced during the fracturing process show a higher b-value in the Gutenberg-Richter scaling relationship than continental earthquakes. We investigate icequakes on the east side of rift WR4 in the Ross Ice Shelf, Antarctica. Our model suggests a maximum icequake slip depth that is similar to 7.8 m below the rift melange, where the slip area can only grow laterally along the fracture planes. We propose ductile deformation below this depth, potentially due to the saturation of unfrozen water. We use remote sensing and geodetic tools to quantify surface movement on different timescales and find that the majority of icequakes occur during falling tides. The total seismic moment is <1% of the estimated geodetic moment during a tidal cycle. This study demonstrates the feasibility of using seismology and geodesy to investigate ice rift zone rheology.

Automated summary

This study investigates icequakes in the rift zone of the Ross Ice Shelf in Antarctica and reveals the slip depth and surface movement patterns during the fracturing process. The results show that the icequake slip depth is approximately 7.8 meters below the rift melange and the majority of icequakes occur during falling tides.