Icequake‐Magnitude Scaling Relationship Along a Rift Within the Ross Ice Shelf, Antarctica

Huang, M. H.; Lopez, Kathrine Udell; Olsen, K.

doi:10.1029/2022gl097961

Cited by 5 publications

(1 citation statement)

References 31 publications

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“…Olinger et al (2019) located more than 2,500 icequakes along rift WR4 near the intersection of the two lines of RIS seismic stations (Figure 1) but did not detect any greater seismicity during the passage of waves from Whillans slip events. This may be due to the fact that rift WR4 is deforming in tension, with icequakes likely confined to the upper few meters of snow and ductile deformation at deeper levels (Huang et al, 2022), whereas the strain pulses from the WIS slip events exert dominantly compressional stress across the entire thickness of the shelf.…”

Section: Discussionmentioning

confidence: 99%

Ross Ice Shelf Displacement and Elastic Plate Waves Induced by Whillans Ice Stream Slip Events

Wiens,

Aster,

Nyblade

et al. 2024

Geophysical Research Letters

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Ice shelves are assumed to flow steadily from their grounding lines to the ice front. We report the detection of ice‐propagating extensional Lamb (plate) waves accompanied by pulses of permanent ice shelf displacement observed by co‐located Global Navigation Satellite System receivers and seismographs on the Ross Ice Shelf. The extensional waves and associated ice shelf displacement are produced by tidally triggered basal slip events of the Whillans Ice Stream, which flows into the ice shelf. The propagation velocity of 2,800 m/s is intermediate between shear and compressional ice velocities, with velocity and particle motions consistent with predictions for extensional Lamb waves. During the passage of the Lamb waves the entire ice shelf is displaced about 60 mm with a velocity more than an order of magnitude above its long‐term flow rate. Observed displacements indicate a peak dynamic strain of 10−7, comparable to that of earthquake surface waves that trigger ice quakes.

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Section: Discussionmentioning

confidence: 99%

Ross Ice Shelf Displacement and Elastic Plate Waves Induced by Whillans Ice Stream Slip Events

Wiens,

Aster,

Nyblade

et al. 2024

Geophysical Research Letters

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Observing glacier dynamics with low-cost, multi-GNSS positioning in Victoria Land, Antarctica

Still,

Odolinski,

Bowman

et al. 2023

J. Glaciol.

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This study examines the performance of low-cost, low-power GNSS positioning systems for glacier monitoring in high-latitude environments. We compare the positioning performance of co-located low-cost u-blox ZED-F9P GNSS units (a few hundred USDs) and survey-grade Trimble R10 units (> $10,000 USD) under stationary (on land) and dynamic (on glacier) conditions near Terra Nova Bay, Antarctica. Low-cost and survey-grade systems yield almost identical error magnitudes under short (3 m), medium (34 km) and long (390 km) baseline kinematic-positioning scenarios. We further examined the efficacy of low-cost GNSS for glaciological applications by installing four u-blox and two Trimble receivers on Priestley Glacier to observe tide-modulated ice flexure. All receivers successfully detected subtle tidal oscillations with amplitudes < 3 cm, consistent with the predicted phasing from a tide model. These experiments offer a strong rationale for the widespread use of low-cost receivers to expand and densify GNSS monitoring networks, both in Antarctica and in glaciated regions worldwide.

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Quantification of geodetic strain rate uncertainties and implications for seismic hazard estimates

Maurer

Materna

2023

Geophysical Journal International

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Summary Geodetic velocity data provide first-order constraints on crustal surface strain rates, which in turn are linked to seismic hazard. Estimating the 2D surface strain tensor everywhere requires knowledge of the surface velocity field everywhere, while geodetic data such as Global Navigation Satellite System (GNSS) only have spatially scattered measurements on the surface of the Earth. To use these data to estimate strain rates, some type of interpolation is required. In this study, we review methodologies for strain rate estimation and compare a suite of methods, including a new implementation based on the geostatistical method of kriging, to compare variation between methods with uncertainty based on one method. We estimate the velocity field and calculate strain rates in southern California using a GNSS velocity field and five different interpolation methods to understand the sources of variability in inferred strain rates. Uncertainty related to data noise and station spacing (aleatoric uncertainty) is minimal where station spacing is dense and maximum far from observations. Differences between methods, related to epistemic uncertainty, are usually highest in areas of high strain rate due to differences in how gradients in the velocity field are handled by different interpolation methods. Parameter choices, unsurprisingly, have a strong influence on strain rate field, and we propose the traditional L-curve approach as one method for quantifying the inherent trade-off between fit to the data and models that are reflective of tectonic strain rates. Doing so, we find total variability between five representative strain rate models to be roughly 40 per cent, a much lower value than roughly 100 per cent that was found in previous studies (Hearn et al., 2010). Using multiple methods to tune parameters and calculate strain rates provides a better understanding of the range of acceptable models for a given velocity field. Finally, we present an open-source Python package (Materna et al., 2021) for calculating strain rates, Strain_2D, which allows for the same data and model grid to be used in multiple strain rate methods, can be extended with other methods from the community, and provides an interface for comparing strain rate models, calculating statistics, and estimating strain rate uncertainty for a given GNSS dataset.

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Icequake‐Magnitude Scaling Relationship Along a Rift Within the Ross Ice Shelf, Antarctica

Cited by 5 publications

References 31 publications

Ross Ice Shelf Displacement and Elastic Plate Waves Induced by Whillans Ice Stream Slip Events

Ross Ice Shelf Displacement and Elastic Plate Waves Induced by Whillans Ice Stream Slip Events

Observing glacier dynamics with low-cost, multi-GNSS positioning in Victoria Land, Antarctica

Quantification of geodetic strain rate uncertainties and implications for seismic hazard estimates

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