Stick‐Slip Tremor Beneath an Alpine Glacier
Abstract Sliding of glacial ice over its base is typically described by a frictionless or slowly deforming bed. This view is challenged by recent seismic observations of stick‐slip motion at the ice‐bed interface. We revisit a high‐frequency (20–35 Hz) harmonic tremor recorded on Gornergletscher, Sw...
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2020GL090528 |
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| author | J. Umlauft F. Lindner P. Roux T. D. Mikesell M. M. Haney M. Korn F. T. Walter |
| author_facet | J. Umlauft F. Lindner P. Roux T. D. Mikesell M. M. Haney M. Korn F. T. Walter |
| author_sort | J. Umlauft |
| collection | DOAJ |
| description | Abstract Sliding of glacial ice over its base is typically described by a frictionless or slowly deforming bed. This view is challenged by recent seismic observations of stick‐slip motion at the ice‐bed interface. We revisit a high‐frequency (20–35 Hz) harmonic tremor recorded on Gornergletscher, Switzerland. In contrast to previous interpretation in terms of glaciohydraulic tremor, we present evidence for superimposed stick‐slip episodes as tremor sources: we locate the tremor source with matched field processing polarity optimization, which allows for azimuthal polarity patterns associated with nonisotropic moment tensors and yields a tremor source clustering near the glacier bed. Our analysis confirms an S wave radiation pattern in agreement with a double‐couple source derived from ice sliding over bedrock and explains our tremor observations in terms of glacier stick‐slip motion. Adding to observations of stick‐slip tremor beneath polar ice streams, this first report on stick‐slip tremor beneath Alpine ice favors widespread seismogenic glacier sliding. |
| format | Article |
| id | doaj-art-a3abe202431c4fb1a1b858e13d0b1e67 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-a3abe202431c4fb1a1b858e13d0b1e672025-08-20T03:07:23ZengWileyGeophysical Research Letters0094-82761944-80072021-01-01482n/an/a10.1029/2020GL090528Stick‐Slip Tremor Beneath an Alpine GlacierJ. Umlauft0F. Lindner1P. Roux2T. D. Mikesell3M. M. Haney4M. Korn5F. T. Walter6Institute of Geophysics and Geology Leipzig University Leipzig GermanyDepartment of Earth and Environmental Sciences LMU Munich Munich GermanyISTerre ‐ Maison des Géosciences Grenoble FranceDepartment of Geosciences Environmental Seismology Laboratory Boise State University Boise ID USAU.S. Geological Survey Alaska Volcano Observatory Anchorage AK USAInstitute of Geophysics and Geology Leipzig University Leipzig GermanyETH Zurich Laboratory of Hydraulics Hydrology and Glaciology Zurich SwitzerlandAbstract Sliding of glacial ice over its base is typically described by a frictionless or slowly deforming bed. This view is challenged by recent seismic observations of stick‐slip motion at the ice‐bed interface. We revisit a high‐frequency (20–35 Hz) harmonic tremor recorded on Gornergletscher, Switzerland. In contrast to previous interpretation in terms of glaciohydraulic tremor, we present evidence for superimposed stick‐slip episodes as tremor sources: we locate the tremor source with matched field processing polarity optimization, which allows for azimuthal polarity patterns associated with nonisotropic moment tensors and yields a tremor source clustering near the glacier bed. Our analysis confirms an S wave radiation pattern in agreement with a double‐couple source derived from ice sliding over bedrock and explains our tremor observations in terms of glacier stick‐slip motion. Adding to observations of stick‐slip tremor beneath polar ice streams, this first report on stick‐slip tremor beneath Alpine ice favors widespread seismogenic glacier sliding.https://doi.org/10.1029/2020GL090528Alpine glaciercryoseismologymatched field processingstick‐slip tremor |
| spellingShingle | J. Umlauft F. Lindner P. Roux T. D. Mikesell M. M. Haney M. Korn F. T. Walter Stick‐Slip Tremor Beneath an Alpine Glacier Geophysical Research Letters Alpine glacier cryoseismology matched field processing stick‐slip tremor |
| title | Stick‐Slip Tremor Beneath an Alpine Glacier |
| title_full | Stick‐Slip Tremor Beneath an Alpine Glacier |
| title_fullStr | Stick‐Slip Tremor Beneath an Alpine Glacier |
| title_full_unstemmed | Stick‐Slip Tremor Beneath an Alpine Glacier |
| title_short | Stick‐Slip Tremor Beneath an Alpine Glacier |
| title_sort | stick slip tremor beneath an alpine glacier |
| topic | Alpine glacier cryoseismology matched field processing stick‐slip tremor |
| url | https://doi.org/10.1029/2020GL090528 |
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