Tidal and thermal stresses drive seismicity along a major Ross Ice Shelf rift

Alternative Title
Date Created
Related Materials
Replaced By
Ross Ice Shelf
Glacial seismology
Ice shelf rifting
Understanding deformation in ice shelves is necessary to evaluate the response of ice shelves to thinning. We study microseismicity associated with ice shelf deformation using nine broadband seismographs deployed near a rift on the Ross Ice Shelf. From December 2014 to November 2016, we detect 5,948 icequakes generated by rift deformation. Locations were determined for 2,515 events using a least squares grid‐search and double‐difference algorithms. Ocean swell, infragravity waves, and a significant tsunami arrival do not affect seismicity. Instead, seismicity correlates with tidal phase on diurnal time scales and inversely correlates with air temperature on multiday and seasonal time scales. Spatial variability in tidal elevation tilts the ice shelf, and seismicity is concentrated while the shelf slopes downward toward the ice front. During especially cold periods, thermal stress and embrittlement enhance fracture along the rift. We propose that thermal stress and tidally driven gravitational stress produce rift seismicity with peak activity in the winter.
Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters, 46(12), (2019): 6644-6652, doi:10.1029/2019GL082842.
Embargo Date
Olinger, S. D., Lipovsky, B. P., Wiens, D. A., Aster, R. C., Bromirski, P. D., Chen, Z., Gerstoft, P., Nyblade, A. A., & Stephen, R. A. (2019). Tidal and thermal stresses drive seismicity along a major ross ice shelf rift. Geophysical Research Letters, 46(12), 6644-6652.
Cruise ID
Cruise DOI
Vessel Name