Transport of volcanic tephra layers in glaciers: a case study at Mýrdalsjökull, Iceland

• Main Authors: Jarosch, Alexander H., Magnússon, Eyjólfur
• Format: Report
• Language: English
• Published: 2022
• Subjects: Ice Flow; Numerical Simulation; Englacial Transport; Katla; Mýrdalsjökull; glacier; Ice cap; Iceland
• Online Access: https://zenodo.org/record/7108369; https://doi.org/10.5281/zenodo.7108369

Volcanic eruptions regularly deposit extended tephra layers on glacier surfaces. Iceland with its rich and well studies volcanic history (Larsen et al. 1998) is an ideal study site for transport mechanisms within glaciers. For the work presented here, we choose the Mýrdalsjökull ice cap, with its prominent central volcano (i.e. Katla) and an extensive data availability (e.g Björnsson et al. 2000, Magnusson 2021). Our numerical simulations build on a two-component, coupled approach utilizing (I) a Full--Stokes ice-flow model and (II) a transport model. This approach allows us to simulate transport processes of initially surface deposited tephra layers in complex glacier flows, which originate from the intrinsic non-linear ice rheology and its interplay with bed topography. After a brief overview on the methods and data used, we present a case study of transporting a homogeneous tephra layer, initially placed just below the ice surface, for a period of 100 years with the prevailing ice flow. In this study, surface mass-balance processes and changes in ice geometry are neglected to focus on the transport mechanisms.