Observation of the Argentière Glacier Flow Variability from 2009 to 2011 by TerraSAR-X and GPS Displacement Measurements

Ponton, Fanny; Trouvé, Emmanuël; Gay, Michel; Walpersdorf, Andréa; Fallourd, Renaud; Nicolas, Jean‐Marie; Vernier, Flavien; Mugnier, Jean‐Louis

doi:10.1109/jstars.2014.2349004

Cited by 15 publications

(20 citation statements)

References 27 publications

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“…Considering the uncertainties on the slope of the linear regression and on the azimuth and incidence angles, and a 5 • uncertainty in the glacier flow direction, the 95% confidence interval is from 9 cm/d to 26 cm/d. The observed changes in t P − t S are thus consistent with displacement of the sensor with the glacier at a velocity of 17 cm/d (measured by GPS SERA in winter, and in the central part of the glacier [Ponton et al, 2014]).…”

Section: Source Migration Over Time?supporting

confidence: 82%

“…Assuming that this variation of d is instead due to vertical displacement of the glacier in response to horizontal strain or to glacier bedrock separation, the estimated vertical displacement of 1.2 m is still 10 times greater than the displacements observed during 'spring events' [ Anderson et al , ; Ponton et al , ]. The observed apparent variations of t S − t P for 10–12 April are thus too large to be explained by either glacier flow or vertical displacement.…”

Section: Source Migration Over Time?mentioning

confidence: 92%

“…(a) Orthophoto of the glacier taken in 2003 (from GLACIOCIM) and inset showing the location of the glacier in France. Green triangle, location of GPS SERA [ Ponton et al , ]. (b) Zoom showing the seismic network.…”

Section: The Study Areamentioning

confidence: 99%

“…Basal seismicity may provide information about the subglacial conditions, such as the bedrock properties [Smith, 2006], stress distribution [Anandakrishnan and Bentley, 1993], subglacial water flow [Winberry et al, 2009], and basal fractures [Walter et al, 2010. [Ponton et al, 2014]. (b) Zoom showing the seismic network.…”

Section: Introductionmentioning

confidence: 99%

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Basal icequakes recorded beneath an Alpine glacier (Glacier d'Argentière, Mont Blanc, France): Evidence for stick‐slip motion?

et al. 2015

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While basal icequakes associated with glacier motion have been detected under Antarctica for several decades, there remains very little evidence of stick‐slip motion for Alpine glaciers. Here we analyzed 2357 basal icequakes that were recorded at Glacier d'Argentière (Mont‐Blanc Massif) between February and November of 2012 and that are likely to be associated with basal sliding. These events have been classified into 18 multiplets, based on their waveforms. The strong similarity of the waveforms within each multiplet suggests an isolated repeating source. Despite this similarity, the peak amplitude within each multiplet varies gradually in time, by up to a factor of 18. The distribution of these events in time is relatively complex. For long time scales, we observe progressive variations in the amplitudes of events within each multiplet. For intermediate time scales (hours), the events occur regularly in time, with typical return times of several minutes up to several hours. For short time scales (from 0.01 to 100 s), the largest multiplet shows clustering in time, with a power law distribution of the interevent times. The location of these events and their focal mechanisms are not well constrained, because most of these events were detected by a single seismometer. Nevertheless, the locations can be estimated with an accuracy of a few tens of meters using a polarization analysis. The estimated average depth of the basal events is 179 m, which is in good agreement with the estimated glacier thickness. The relative changes in distance between the source and the sensor can be measured accurately by correlating separately the P wave and S wave parts of the seismograms of each event with the template waveforms, which are obtained by averaging the signals within each multiplet. We observed small variations in the times between the P wave and the S wave of up to 0.6 ms over 50 days. These variations cannot be explained by displacement of the sensor with respect to the glacier but might be due to small changes in the seismic wave velocities with time. Finally, we found using numerical simulations that the observed signals are better explained by a horizontal shear fault with slip parallel to the glacier flow than by a tensile fault. These results suggest that the basal events are associated with stick‐slip motion of the glacier over rough bedrock. The rupture length and the slip are difficult to estimate. Nonetheless, the rupture length is likely to be of the order of meters, and the total seismic slip accumulated over one day might be as large as the glacier motion during the most active bursts.

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Section: Source Migration Over Time?supporting

confidence: 82%

Section: Source Migration Over Time?mentioning

confidence: 92%

Section: The Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Basal icequakes recorded beneath an Alpine glacier (Glacier d'Argentière, Mont Blanc, France): Evidence for stick‐slip motion?

et al. 2015

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“…La combinaison de résultats issus d'orbites ascendantes et descendantes permet de reconstruire des champs de déplacement 3D (est, nord, vertical). Les performances de la corrélation d'amplitude dépendent de la taille des pixels, de la présence de texture ou de la cohérence du chatoiement (speckle en anglais : scintillement du aux interférences entre le signal rétrodiffusé de chaque cible au sein d'un pixel homogène) entre les acquisitions (Ponton et al, 2014). L'interférométrie différentielle permet de mesurer des déplacements centimétriques, voire millimétriques, mais nécessite une grande stabilité de la rétrodiffusion, ce qui peut s'avérer problématique sur des glaciers où l'état de surface évolue rapidement (fonte, précipitations…).…”

Section: Vitesses D'écoulement Des Glaciers En Surfaceunclassified

Télédétection satellitaire des surfaces enneigées et englacées

Rabatel¹,

Berthier²,

Arnaud³

et al. 2017

Météorologie

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RésuméCet article présente une vue d'ensemble des avancées récentes en télédétection spatiale appliquée à l'étude des surfaces enneigées et englacées auxquelles la communauté scientifique française a participé. Qu'ils s'agissent de données satellitaires optique, radar, lidar ou gravimétrique, ces travaux sur la couverture nivale saisonnière ou pérenne, les glaciers de montagne, les calottes polaires, la glace de mer ou de lac et de rivière ont pour objectifs de documenter aussi bien les caractéristiques physiques de ces objets que leur variabilité spatiotemporelle aux échelles locale, régionale ou globale. AbstractSatellite remote sensing of snow and ice-covered surfaces

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Time-lapse optical flow regularization for geophysical complex phenomena monitoring

Hadhri

Vernier

Atto

et al. 2019

ISPRS Journal of Photogrammetry and Remote Sensing

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Observation of the Argentière Glacier Flow Variability from 2009 to 2011 by TerraSAR-X and GPS Displacement Measurements

Cited by 15 publications

References 27 publications

Basal icequakes recorded beneath an Alpine glacier (Glacier d'Argentière, Mont Blanc, France): Evidence for stick‐slip motion?

Basal icequakes recorded beneath an Alpine glacier (Glacier d'Argentière, Mont Blanc, France): Evidence for stick‐slip motion?

Télédétection satellitaire des surfaces enneigées et englacées

Time-lapse optical flow regularization for geophysical complex phenomena monitoring

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