A Multi-Physics Experiment with a Temporary Dense Seismic Array on the Argentière Glacier, French Alps: The RESOLVE Project

Abstract

Recent work in the field of cryo-seismology demonstrates that high-frequency (>1 Hz) seismic waves provide key constraints on a wide range of glacier processes, such as basal friction, surface crevassing, or subglacial water flow. Establishing quantitative links between the seismic signal and the processes of interest, however, requires detailed characterization of the wavefield, which, at high frequencies, necessitates the deployment of large and dense seismic arrays. Although dense seismic array monitoring has recently become increasingly common in geophysics, its application to glaciated environments remains limited. Here, we present a dense seismic array experiment made of 98 three-component seismic stations continuously recording during 35 days in early spring 2018 on the Argentière Glacier, French Alps. The seismic dataset is supplemented with a wide range of complementary observations obtained from ground-penetrating radar, drone imagery, Global Navigation Satellite Systems positioning, and in situ measurements of basal glacier sliding velocities and subglacial water discharge. We present first results through conducting spectral analysis, template matching, matched-field processing, and eikonal-wave tomography. We report enhanced spatial resolution on basal stick slip and englacial fracturing sources as well as novel constraints on the heterogeneous nature of the noise field generated by subglacial water flow and on the link between crevasse properties and englacial seismic velocities. We outline in which ways further work using this dataset could help tackle key remaining questions in the field.

Observing the subglacial hydrology network and its dynamics with a dense seismic array

“…We refer to this maximum correlation as the MFP output, which ranges from 0 to 1. An MFP output close to 1 indicates global phase coherence, as expected for a dominant and punctual source (36), while a low MFP output indicates several local phase coherences, as expected for multiple sources simultaneously acting over the area. We note that we only keep the sources that are located within 400 m of the center of our array and are associated with realistic physical properties (i.e., wave velocities, source depth; Fig.…”

“…These locations correspond to real and detectable seismic events, since MFP output is much higher than expected for random noise (refer to ref. 30, Fig. 9).…”

“…The reader should refer to ref. 30 for the detailed description of the complementary data associated with this seismic experiment.…”

“…Materials and Methods and ref. 30 for detailed description of the experiment and ref. 23 for a broader glaciological context).…”

“…The spatial maps of source locations, glacier geometries, and hydraulic potentials as well as the code used to processed these data are publically accessible at https://zenodo.org/record/4024660 (64). Part of the dataset of the seismic signals acquired during RESOLVE-Argentière is publically accessible at https://doi.org/10.1785/0220200280 (36) in link with ref. 30.…”