Mechanics of tidally driven fractures in Europa's ice shell

Lee, Sunwoong; Pappalardo, R.; Makris, Nicholas C.

doi:10.1016/j.icarus.2005.07.003

Cited by 56 publications

(58 citation statements)

References 38 publications

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“…Previous workers have calculated a relation between stress and the thickness of a brittle shell that can be opened by a crack in a half-space (e.g., Weertman, 1973). Lee et al (2005) find values of brittle ice that can be cracked by given stress levels three to ten times thicker than these previous estimates, depending on assumed ice porosity structure.…”

contrasting

confidence: 51%

“…The maximum opening depth is taken to be where the magnitudes of the opposing factors are equal. Such an approach would be valid if the two factors were computed for the same layer geometry, but this does not appear to be what was done by Lee et al (2005).…”

mentioning

confidence: 96%

“…To make these estimates of "crackable" ice layer thickness Lee et al (2005) employ a stress intensity factor analysis for the opening of a vertical tensile crack to a depth h in an elastic layer of thickness H (Fig. 1).…”

mentioning

confidence: 99%

“…The problem with the formulation of Lee et al (2005) appears to be in the way that the hydrostatic stress ρ i gz related stress intensity factor is calculated. Their discussion of the difference between the tensional and hydrostatic factors in Section 3.1 of Lee et al (2005) makes the problem clear.…”

mentioning

confidence: 99%

“…Their discussion of the difference between the tensional and hydrostatic factors in Section 3.1 of Lee et al (2005) makes the problem clear. They correctly describe how the application of far-field tension σ ∞ to a layer of thickness H with a crack extending from the surface to a depth z = h produces a concentration of stress around the crack tip.…”

mentioning

confidence: 99%

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Comment on “Mechanics of tidally driven fractures in Europa's ice shell” by S. Lee, R.T. Pappalardo, and N.C. Makris [2005. Icarus 177, 367–379]

Qin

Buck

Germanovich

2007

Icarus

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contrasting

confidence: 51%

mentioning

confidence: 96%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Comment on “Mechanics of tidally driven fractures in Europa's ice shell” by S. Lee, R.T. Pappalardo, and N.C. Makris [2005. Icarus 177, 367–379]

Qin

Buck

Germanovich

2007

Icarus

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Expected Seismicity and the Seismic Noise Environment of Europa

et al. 2018

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Seismic data will be a vital geophysical constraint on internal structure of Europa if we land instruments on the surface. Quantifying expected seismic activity on Europa both in terms of large, recognizable signals and ambient background noise is important for understanding dynamics of the moon, as well as interpretation of potential future data. Seismic energy sources will likely include cracking in the ice shell and turbulent motion in the oceans. We define a range of models of seismic activity in Europa's ice shell by assuming each model follows a Gutenberg‐Richter relationship with varying parameters. A range of cumulative seismic moment release between 1016 and 1018 Nm/yr is defined by scaling tidal dissipation energy to tectonic events on the Earth's moon. Random catalogs are generated and used to create synthetic continuous noise records through numerical wave propagation in thermodynamically self‐consistent models of the interior structure of Europa. Spectral characteristics of the noise are calculated by determining probabilistic power spectral densities of the synthetic records. While the range of seismicity models predicts noise levels that vary by 80 dB, we show that most noise estimates are below the self‐noise floor of high‐frequency geophones but may be recorded by more sensitive instruments. The largest expected signals exceed background noise by ∼50 dB. Noise records may allow for constraints on interior structure through autocorrelation. Models of seismic noise generated by pressure variations at the base of the ice shell due to turbulent motions in the subsurface ocean may also generate observable seismic noise.

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Experimental Constraints on the Fatigue of Icy Satellite Lithospheres by Tidal Forces

et al. 2018

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Fatigue can cause materials that undergo cyclic loading to experience brittle failure at much lower stresses than under monotonic loading. We propose that the lithospheres of icy satellites could become fatigued and thus weakened by cyclical tidal stresses. To test this hypothesis, we performed a series of laboratory experiments to measure the fatigue of water ice at temperatures of 198 K and 233 K and at a loading frequency of 1 Hz. We find that ice is not susceptible to fatigue at our experimental conditions and that the brittle failure stress does not decrease with increasing number of loading cycles. Even though fatigue was not observed at our experimental conditions, colder temperatures, lower loading frequencies, and impurities in the ice shells of icy satellites may increase the likelihood of fatigue crack growth. We also explore other mechanisms that may explain the weak behavior of the lithospheres of some icy satellites.

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Mechanics of tidally driven fractures in Europa's ice shell

Cited by 56 publications

References 38 publications

Comment on “Mechanics of tidally driven fractures in Europa's ice shell” by S. Lee, R.T. Pappalardo, and N.C. Makris [2005. Icarus 177, 367–379]

Comment on “Mechanics of tidally driven fractures in Europa's ice shell” by S. Lee, R.T. Pappalardo, and N.C. Makris [2005. Icarus 177, 367–379]

Expected Seismicity and the Seismic Noise Environment of Europa

Experimental Constraints on the Fatigue of Icy Satellite Lithospheres by Tidal Forces

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