A general theory of rock glacier creep based on in‐situ and remote sensing observations

Abstract

The ongoing acceleration in rock glacier velocities concurrent with increasing air temperatures, and the widespread onset of rock glacier destabilization have reinforced the interest in rock glacier dynamics and in its coupling to the climate system. Despite the increasing number of studies investigating this phenomenon, our knowledge of both the fundamental mechanisms controlling rock glacier dynamics, and their long‐term behaviour at the regional scale remain limited. We present a general theory to investigate rock glacier dynamics, its spatial patterns and temporal trends at both regional and local scale. To this end, we combine a model to calculate rock glacier thickness with an empirical creep model for ice‐rich debris, in order to derive the Bulk Creep Factor (BCF), which allows to disentangle the two contributions to the surface velocities from (i) material properties and (ii) geometry. Thereafter, we provide two examples of possible applications of this approach at a regional and local scale.

Deciphering the evolution of the Bleis Marscha rock glacier (Val d'Err, eastern Switzerland) with cosmogenic nuclide exposure dating, aerial image correlation, and finite element modeling

“…ess.washington.edu/math, last access: 22 April 2021). The NENA production rate has been shown to be well applicable for the Alpine area (Claude et al, 2014). The 36 Cl surface exposure age was computed with a LIP in-housedeveloped MATLAB program based on the equations and constants given in Alfimov and Ivy-Ochs (2009, and references therein).…”

Kinematic observations of the mountain cryosphere using in-situ GNSS instruments

“…(Delaloye et al, 2013;Wirz et al, 2014b). The method devised in this initial project (Buchli et al, 2012;Wirz et al, 2013) has proven very successful and was thus expanded to other locations and applications of monitoring (Kenner et al, 2018;Cicoira et al, 2021) as well as natural hazard mitigation (Kenner et al, 2020) in collaboration with partners of the Swiss Permafrost Monitoring Network (PERMOS), the Swiss cantonal and federal authorities (Randa Grossgufer, Wysse Schije, PERMOS GNSS sites) (Noetzli et al, 2019). The methodological approach and technology used is closely related to work that was pioneered at the Matterhorn Hörnligrat field site from 2008 (Talzi et al, 2007;Hasler et al, 2008) as well as the Jungfraujoch (Hasler et al, 2011).…”

“…The success of this in-situ kinematic monitoring methods and instrumentation developed in the context of the X-Sense project is further manifested by the fact that this technology has been chosen to also monitor sites with similar properties as the above mentioned in other regions of Switzerland. The Schafberg (Kenner et al, 2020), Muragl (Kääb et al, 1997;Kaeaeb et al, 1998), and Murtel-Corvatsch rock glaciers (Cicoira et al, 2019a(Cicoira et al, , 2021 are situated in the Upper Engadin valley and the Largario rock glacier is situated in the Blenio valley, TI (Scapozza et al, 2014).…”

“…In the year 2018 two more positions were instrumented on the fast moving tongue, with the goal of creating a spatially resolved network for the analysis of the spatial variability of rock glacier velocities at a daily scale (Cicoira et al, 2019b(Cicoira et al, , 2021.…”

“…In the same years, also vertical inclinometer profiles were measured manually, providing a unique dataset. Recent detailed process oriented studies are based on the dataset presented (Cicoira et al, 2019a(Cicoira et al, , 2021.…”