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Simultaneous teleseismic and geodetic observations of the stick–slip motion of an Antarctic ice stream


Long-period seismic sources associated with glacier motion have been recently discovered1,2, and an increase in ice flow over the past decade has been suggested on the basis of secular changes in such measurements3. Their significance, however, remains uncertain, as a relationship to ice flow has not been confirmed by direct observation. Here we combine long-period surface-wave observations with simultaneous Global Positioning System measurements of ice displacement to study the tidally modulated stick–slip motion of the Whillans Ice Stream in West Antarctica4,5. The seismic origin time corresponds to slip nucleation at a region of the bed of the Whillans Ice Stream that is likely stronger than in surrounding regions and, thus, acts like an ‘asperity’ in traditional fault models. In addition to the initial pulse, two seismic arrivals occurring 10–23 minutes later represent stopping phases as the slip terminates at the ice stream edge and the grounding line. Seismic amplitude and average rupture velocity are correlated with tidal amplitude for the different slip events during the spring-to-neap tidal cycle. Although the total seismic moment calculated from ice rigidity, slip displacement, and rupture area is equivalent to an earthquake of moment magnitude seven (Mw 7), seismic amplitudes are modest (Ms 3.6–4.2), owing to the source duration of 20–30 minutes. Seismic radiation from ice movement is proportional to the derivative of the moment rate function at periods of 25–100 seconds and very long-period radiation is not detected, owing to the source geometry. Long-period seismic waves are thus useful for detecting and studying sudden ice movements but are insensitive to the total amount of slip.

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Figure 1: The Whillans Ice Stream, the positions of the sensors and the positions of the slip nucleation and seismic source locations.
Figure 2: GPS and seismic records of Whillans slip events.
Figure 3: The effect of Ross Sea tidal amplitude on seismograms and the average rupture velocity from GPS.
Figure 4: Modelling the initial seismic signals of the slip events.


  1. Ekstrom, G., Nettles, M. & Abers, G. A. Glacial earthquakes. Science 302, 622–624 (2003)

    Article  ADS  Google Scholar 

  2. Tsai, V. C. & Ekstrom, G. Analysis of glacial earthquakes. J. Geophys. Res. 112, 10.1029/2006JF000596 (2007)

  3. Ekstrom, G., Nettles, M. & Tsai, V. C. Seasonality and increasing frequency of Greenland glacial earthquakes. Science 311, 1756–1758 (2006)

    Article  ADS  Google Scholar 

  4. Bindschadler, R. A., King, M. A., Alley, R. B., Anandakrishnan, S. & Padman, L. Tidally controlled stick-slip discharge of a West Antarctic Ice Stream. Science 301, 1087–1089 (2003)

    Article  ADS  CAS  Google Scholar 

  5. Bindschadler, R. A., Vornberger, P. L., King, M. A. & Padman, L. Tidally driven stick-slip motion in the month of Whillans Ice Stream, Antarctica. Ann. Glaciol. 36, 263–272 (2003)

    Article  ADS  Google Scholar 

  6. Bindschadler, R. A. & Bentley, C. R. On thin ice? Sci. Am. 287, 98–105 (2002)

    Article  Google Scholar 

  7. de Angelis, H. & Skvarca, P. Glacier surge after ice shelf collapse. Science 299, 1560–1562 (2003)

    Article  ADS  CAS  Google Scholar 

  8. Scambos, T., Bohlander, J., Shuman, C. & Skvarca, P. Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica. Geophys. Res. Lett. 31 10.1029/2004GL020670 (2004)

  9. Fischer, U. H. & Clarke, G. K. C. Stick-slip sliding behaviour at the base of a glacier. Ann. Glaciol. 24, 390–396 (1997)

    Article  ADS  Google Scholar 

  10. Aki, K. Generation and propagation of G waves from the Niigata earthquake of June 16, 1964. Part 2. Estimation of earthquake moment, released energy, and stress-strain drop from the G-wave spectrum. Bull. Earthq. Res. Inst., Tokyo Univ. 44, 73–88 (1966)

    Google Scholar 

  11. Wiens, D. A., Anandakrishnan, S., Nyblade, A. & Aleqabi, G. Remote detection and monitoring of glacial slip from Whillans Ice Stream using seismic Rayleigh waves recorded by the TAMSEIS array. Eos 87, abstr.–S44A-04 (2006)

  12. Joughin, I. et al. Continued deceleration of Whillans Ice Stream, West Antarctica. Geophys. Res. Lett. 32 10.1029/2005GL024319 (2005)

    Article  Google Scholar 

  13. Bindschadler, R. A., Stephenson, S. N., MacAyeal, D. R. & Shabtaie, S. Ice dynamics at the mouth of Ice Stream B, Antarctica. J. Geophys. Res. 92, 8885–8894 (1987)

    Article  ADS  Google Scholar 

  14. Alley, R. B. In search of ice-stream sticky spots. J. Glaciol. 39, 447–454 (1993)

    Article  Google Scholar 

  15. Peters, M. E., Blankenship, D. D. & Morse, D. L. Analysis techniques for coherent airborne radar sounding: Application to West Antarctic ice streams. J. Geophys. Res. 110 10.1029/2004JB003222 (2005)

  16. Das, S. & Aki, K. Fault planes with barriers: A versatile earthquake model. J. Geophys. Res. 82, 5648–5670 (1977)

    Article  ADS  Google Scholar 

  17. Lay, T. & Kanamori, H. in Earthquake Prediction: An International Review (eds Simpson, D. W. & Richards, P. G.) 579–592 (American Geophysical Union, Washington DC, 1981)

    Google Scholar 

  18. Anandakrishnan, S., Voigt, D. E., Alley, R. B. & King, M. A. Ice stream D flow speed is strongly modulated by the tide beneath the Ross Ice Shelf. Geophys. Res. Lett. 30 10.1029/2002GL016329 (2003)

  19. Russell, D. R. Development of a time-domain, variable-period surface-wave magnitude measurement procedure for application at regional and teleseismic distances. Bull. Seismol. Soc. Am. 96, 665–677 (2006)

    Article  Google Scholar 

  20. Beroza, G. C. & Jordan, T. H. Searching for slow and silent earthquakes using free oscillations. J. Geophys. Res. 95, 2485–2510 (1990)

    Article  ADS  Google Scholar 

  21. Rhie, J. & Romanowicz, B. Excitation of the Earth's continuous free oscillations by atmosphere-ocean-seafloor coupling. Nature 431, 552–556 (2004)

    Article  ADS  CAS  Google Scholar 

  22. Kanamori, H. & Given, J. W. Use of long-period surface waves for rapid determination of earthquake source parameters. Phys. Earth Planet. Inter. 27, 8–31 (1981)

    Article  ADS  Google Scholar 

  23. Suda, N., Kazunari, K. & Fukao, Y. Earth's background free oscillations. Science 279, 2089–2091 (1998)

    Article  ADS  CAS  Google Scholar 

  24. Horgan, H. J. & Anandakrishnan, S. Static grounding lines and dynamic ice streams: Evidence from the Siple Coast, West Antarctica. Geophys. Res. Lett. 33 10.1029/2006GL027091 (2006)

  25. Padman, L., Fricker, H. A., Coleman, R., Howard, S. L. & Erofeeva, S. A new tidal model for the Antarctic ice shelves and seas. Ann. Glaciol. 34, 247–254 (2002)

    Article  ADS  Google Scholar 

  26. Zumberge, J. F., Heflin, M. B., Jefferson, D. C., Watkins, M. M. & Webb, F. H. Precise point positioning for the efficient and robust analysis of GPS data from large networks. J. Geophys. Res. 102, 5005–5017 (1997)

    Article  ADS  Google Scholar 

  27. Chen, G. GPS Kinematics Positioning for the Airborne Laser Altimetry at Long Valley, California. PhD thesis, Massachusetts Institute of Technology (1998)

    Google Scholar 

  28. Dow, J. M., Neilan, R. E. & Gendt, G. The international GPS service: celebrating the 10th anniversary and looking to the next decade. Adv. Space Res. 36, 320–326 (2005)

    Article  ADS  Google Scholar 

  29. Eissler, H. K. & Kanamori, H. A single-force model for the 1975 Kalapana, Hawaii, earthquake. J. Geophys. Res. 92, 4827–4836 (1987)

    Article  ADS  Google Scholar 

  30. Kawakatsu, H. Centroid single force inversion of seismic waves generated by landslides. J. Geophys. Res. 94, 12363–12374 (1989)

    Article  ADS  Google Scholar 

  31. Dahlen, F. A. Single-force representation of shallow landslide sources. Bull. Seismol. Soc. Am. 83, 130–143 (1993)

    Google Scholar 

  32. Anandakrishnan, S. & Winberry, J. P. Antarctic subglacial sedimentary layer thickness from receiver function analysis. Global Planet. Change 42, 167–176 (2004)

    Article  ADS  Google Scholar 

  33. Kennett, B. L. N. Seismic Wave Propagation in Stratified Media (Cambridge Univ. Press, Cambridge, UK, 1983)

    Google Scholar 

  34. Lawrence, J. F. et al. Rayleigh wave phase velocity analysis of the Ross Sea, Transantarctic Mountains, and East Antarctica from a temporary seismic deployment. J. Geophys. Res. 111 10.1029/2005GL024523 (2006)

    Google Scholar 

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GPS receivers for the TIDES project were supplied by the University NAVSTAR Consortium. Seismic data were obtained from the Data Management Center of the Incorporated Research Institutions for Seismology. This research was funded by the Office of Polar Programs, US National Science Foundation. M.A.K. was partially funded by a NERC (UK) research fellowship. We thank R. B. Alley, R. A. Bindschadler, H. Horgan, I. Joughin, L. Peters and D. E. Voigt for planning and carrying out the TIDES field deployment.

Author Contributions D.A.W. found the ice slip signals on the seismic records and carried out the seismic processing and modelling. D.A.W. also filtered the GPS time series and calculated the slip nucleation locations and times from the GPS records. S.A. and J.P.W. carried out the GPS fieldwork and calculated the displacement time series from the three-dimensional GPS data. M.A.K. processed the raw GPS data to obtain the three-dimensional displacement time series. All authors participated in the interpretation of the results and preparing the paper.

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Correspondence to Douglas A. Wiens.

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Wiens, D., Anandakrishnan, S., Winberry, J. et al. Simultaneous teleseismic and geodetic observations of the stick–slip motion of an Antarctic ice stream. Nature 453, 770–774 (2008).

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