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Western US intermountain seismicity caused by changes in upper mantle flow

Nature volume 524, pages 458–461 (2015)Cite this article

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Abstract

Understanding the causes of intraplate earthquakes is challenging, as it requires extending plate tectonic theory to the dynamics of continental deformation. Seismicity in the western United States away from the plate boundary is clustered along a meandering, north–south trending ‘intermountain’ belt1. This zone coincides with a transition from thin, actively deforming to thicker, less tectonically active crust and lithosphere. Although such structural gradients have been invoked to explain seismicity localization2,3, the underlying cause of seismicity remains unclear. Here we show results from improved mantle flow models that reveal a relationship between seismicity and the rate change of ‘dynamic topography’ (that is, vertical normal stress from mantle flow). The associated predictive skill is greater than that of any of the other forcings we examined. We suggest that active mantle flow is a major contributor to seismogenic intraplate deformation, while gravitational potential energy variations have a minor role. Seismicity localization should occur where convective changes in vertical normal stress are modulated by lithospheric strength heterogeneities. Our results on deformation processes appear consistent with findings from other mobile belts4, and imply that mantle flow plays a significant and quantifiable part in shaping topography, tectonics, and seismic hazard within intraplate settings.

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Figure 1: Structural and geodynamic maps for the study region.
Figure 2: Analysis of predictive power for intraplate seismicity.
Figure 3: Illustration of mantle flow forcing in the study region.

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References

  1. Herrmann, R. B., Benz, H. & Ammon, C. J. Monitoring the earthquake process in North America. Bull. Seismol. Soc. Am. 101, 2609–2625 (2011)

    Article  Google Scholar 

  2. Lowry, A. R. & Smith, R. B. Strength and rheology of the western U.S. Cordillera. J. Geophys. Res. 100, 17947–17963 (1995)

    Article  ADS  Google Scholar 

  3. Levander, A. & Miller, M. S. Evolutionary aspects of the lithosphere discontinuity structure in the western U.S. Geochem. Geophys. Geosys. 13, 1525–2027 (2012)

    Article  Google Scholar 

  4. Faccenna, C. & Becker, T. W. Shaping mobile belts by small-scale convection. Nature 465, 602–605 (2010)

    Article  CAS  ADS  Google Scholar 

  5. Artyushkov, E. V. Stresses in the lithosphere caused by crustal thickness inhomogeneities. J. Geophys. Res. 78, 7675–7708 (1973)

    Article  ADS  Google Scholar 

  6. Jones, C. H., Unruh, J. R. & Sonder, L. J. The role of gravitational potential energy in active deformation in the southwestern United States. Nature 381, 37–41 (1996)

    Article  CAS  ADS  Google Scholar 

  7. Bird, P. Lateral extrusion of lower crust from under high topography, in the isostatic limit. J. Geophys. Res. 96, 10275–10286 (1991)

    Article  ADS  Google Scholar 

  8. Fay, N. P., Bennett, R. A., Spinler, J. C. & Humphreys, E. D. Small-scale upper mantle convection and crustal dynamics in southern California. Geochem. Geophys. Geosys. 9, Q08006 (2008)

    Article  ADS  Google Scholar 

  9. van Wijk, J. W. et al. Small-scale convection at the edge of the Colorado Plateau: Implications for topography, magmatism, and evolution of Proterozoic lithosphere. Geology 38, 611–614 (2010)

    Article  CAS  ADS  Google Scholar 

  10. Forte, A. M., Mitrovica, J. X., Moucha, R., Simmons, N. A. & Grand, S. P. Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone. Geophys. Res. Lett. 34, L04308 (2007)

    Article  ADS  Google Scholar 

  11. Lowry, A. R. & Pérez-Gussinyé, M. The role of crustal quartz in controlling Cordilleran deformation. Nature 471, 353–357 (2011)

    Article  CAS  ADS  Google Scholar 

  12. Schmandt, B. & Lin, F.-C. P and S wave tomography of the mantle beneath the United States. Geophys. Res. Lett. 41, 6342–6349 (2014)

    Article  ADS  Google Scholar 

  13. Becker, T. W., Faccenna, C., Humphreys, E. D., Lowry, A. R. & Miller, M. S. Static and dynamic support of western U.S. topography. Earth Planet. Sci. Lett. 402, 234–246 (2014)

    Article  CAS  ADS  Google Scholar 

  14. Schmandt, B., Jacobsen, S. D., Becker, T. W., Liu, Z. & Dueker, K. G. Dehydration melting at the top of the lower mantle. Science 344, 1265–1268 (2014)

    Article  CAS  ADS  Google Scholar 

  15. Lowry, A. R., Ribe, N. M. & Smith, R. B. Dynamic elevation of the Cordillera, western United States. J. Geophys. Res. 105, 23371–23390 (2000)

    Article  ADS  Google Scholar 

  16. Flesch, L. M., Holt, W. E., Haines, A. J. & Shen-Tu, B. Dynamics of the Pacific–North American plate boundary in the western United States. Science 287, 834–836 (2000)

    Article  CAS  ADS  Google Scholar 

  17. Humphreys, E. D. & Coblentz, D. North American dynamics and western U.S. tectonics. Rev. Geophys. 45, RG3001 (2007)

    Article  ADS  Google Scholar 

  18. Forte, A. M., Moucha, R., Simmons, N., Grand, S. & Mitrovica, J. Deep-mantle contributions to the surface dynamics of the North American continent. Tectonophys. 481, 3–15 (2010)

    Article  Google Scholar 

  19. Ghosh, A., Becker, T. W. & Humphreys, E. D. Dynamics of the North American continent. Geophys. J. Int. 194, 651–669 (2013)

    Article  ADS  Google Scholar 

  20. Molchan, G. M. & Kagan, Y. Y. Earthquake prediction and its optimization. J. Geophys. Res. 97, 4823–4838 (1992)

    Article  ADS  Google Scholar 

  21. Zechar, J. & Jordan, T. Testing alarm-based earthquake predictions. Geophys. J. Int. 172, 715–724 (2008)

    Article  ADS  Google Scholar 

  22. Richards, M. & Hager, B. H. Geoid anomalies in a dynamic Earth. J. Geophys. Res. 89, 5987–6002 (1984)

    Article  ADS  Google Scholar 

  23. Gurnis, M., Mitrovica, J. X., Ritsema, J. & van Heijst, H.-J. Constraining mantle density structure using geological evidence of surface uplift rates: the case of the African superplume. Geochem. Geophys. Geosys. 1, 1020 (2000)

    Article  ADS  Google Scholar 

  24. Conrad, C. P. & Husson, L. Influence of dynamic topography on sea level and its rate of change. Lithosphere 1, 110–120 (2009)

    Article  ADS  Google Scholar 

  25. Faccenna, C. et al. Mantle dynamics in the Mediterranean. Rev. Geophys. 52, 283–332 (2014)

    Article  ADS  Google Scholar 

  26. Faccenna, C., Becker, T. W., Miller, M. S., Serpelloni, E. & Willett, S. D. Isostasy, dynamic topography, and the elevation of the Apennines of Italy. Earth Planet. Sci. Lett. 407, 163–174 (2014)

    Article  CAS  ADS  Google Scholar 

  27. D’Agostino, N. & McKenzie, D. Convective support of long wavelength topography in the Apennines (Italy). Terra Nova 11, 234–238 (1999)

    ADS  Google Scholar 

  28. Wessel, P. & Smith, W. H. F. New, improved version of the Generic Mapping Tools released. Eos Trans. AGU 79, 579 (1998)

    Article  ADS  Google Scholar 

  29. Ekström, G., Nettles, M. & Dziewo’nski, A. M. The global CMT project 2004–2010: centroid-moment tensors for 13,017 earthquakes. Phys. Earth Planet. Inter. 200–201, 1–9 (2012)

    Article  ADS  Google Scholar 

  30. Kreemer, C., Blewitt, G. & Klein, E. C. A geodetic plate motion and Global Strain Rate Model. Geochem. Geophys. Geosys. 15, 3849–3889 (2014)

    Article  ADS  Google Scholar 

  31. Levandowski, W., Jones, C. H., Shen, W., Ritzwoller, M. H. & Schulte-Pelkum, V. Origins of topography in the western U.S.: mapping crustal and upper mantle density variations using a uniform seismic velocity model. J. Geophys. Res. 119, 2375–2396 (2014)

    Article  ADS  Google Scholar 

  32. Liu, L. & Gurnis, M. Dynamic subsidence and uplift of the Colorado Plateau. Geology 38, 663–666 (2010)

    Article  ADS  Google Scholar 

  33. Moresi, L. N. & Solomatov, V. S. Numerical investigations of 2D convection with extremely large viscosity variations. Phys. Fluids 7, 2154–2162 (1995)

    Article  ADS  Google Scholar 

  34. Zhong, S., Zuber, M. T., Moresi, L. & Gurnis, M. Role of temperature-dependent viscosity and surface plates in spherical shell models of mantle convection. J. Geophys. Res. 105, 11063–11082 (2000)

    Article  ADS  Google Scholar 

  35. Auer, L., Boschi, L., Becker, T. W., Nissen-Meyer, T. & Giardini, D. Savani: a variable-resolution whole-mantle model of anisotropic shear-velocity variations based on multiple datasets. J. Geophys. Res. 119, 3006–3034 (2014)

    Article  ADS  Google Scholar 

  36. Burov, E. & Guillou-Frottier, L. The plume head-continental lithosphere interaction using a tectonically realistic formulation for the lithosphere. Geophys. J. Int. 161, 469–490 (2005)

    Article  ADS  Google Scholar 

  37. Braun, J. The many surface expressions of mantle dynamics. Nature Geosci. 3, 825–833 (2010)

    Article  CAS  ADS  Google Scholar 

  38. Becker, T. W. On recent seismic tomography for the western United States. Geochem. Geophys. Geosys. 13, Q01W10 (2012)

    Article  Google Scholar 

  39. Schmandt, B. & Humphreys, E. Complex subduction and small-scale convection revealed by body-wave tomography of the western United States upper mantle. Earth Planet. Sci. Lett. 297, 435–445 (2010)

    Article  CAS  ADS  Google Scholar 

  40. Lou, X. & van der Lee, S. Observed and predicted North American teleseismic delay times. Earth Planet. Sci. Lett. 402, 6–15 (2014)

    Article  CAS  ADS  Google Scholar 

  41. Perry, H. K. C., Forte, A. M. & Eaton, D. W. S. Upper-mantle thermochemical structure below North America from seismic-geodynamic flow models. Geophys. J. Int. 154, 279–299 (2003)

    Article  ADS  Google Scholar 

  42. Moucha, R. et al. Deep mantle forces and the uplift of the Colorado Plateau. Geophys. Res. Lett. 36, L19310 (2009)

    Article  ADS  Google Scholar 

  43. NCEDC. Northern California Earthquake Data Center: Dataset (UC Berkeley Seismological Laboratory, 2014)

  44. Engdahl, E. R., van der Hilst, R. D. & Buland, R. Global teleseismic earthquake relocation with improved travel times and procedures for depth determination. Bull. Seismol. Soc. Am. 88, 722–743 (1998)

    Google Scholar 

  45. Serpelloni, E., Faccenna, C., Spada, G., Dong, D. & Williams, S. D. P. Vertical GPS ground motion rates in the Euro-Mediterranean region: new evidence of velocity gradients at different spatial scales along the Nubia-Eurasia plate boundary. J. Geophys. Res. 118, 6003–6024 (2013)

    Article  ADS  Google Scholar 

  46. Borsa, A. A., Agnew, D. C. & Cayan, D. R. Ongoing drought-induced uplift in the western United States. Science 345, 1587–1590 (2014)

    Article  CAS  ADS  Google Scholar 

  47. Shen, W., Ritzwoller, M. H. & Schulte-Pelkum, V. Crustal and uppermost mantle structure in the central U.S. encompassing the Midcontinent Rift. J. Geophys. Res. 118, 4325–4344 (2013)

    Article  ADS  Google Scholar 

  48. Obrebski, M., Allen, R. M., Pollitz, F. & Hung, S.-H. Lithosphere–asthenosphere interaction beneath the western United States from the joint inversion of body-wave traveltimes and surface-wave phase velocities. Geophys. J. Int. 185, 1003–1021 (2011)

    Article  ADS  Google Scholar 

  49. James, D. E., Fouch, M. J., Carlson, R. W. & Roth, J. B. Slab fragmentation, edge flow and the origin of the Yellowstone hotspot track. Earth Planet. Sci. Lett. 311, 124–135 (2011)

    Article  CAS  ADS  Google Scholar 

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Acknowledgements

We thank C. Kreemer for publishing his geodetic strain-rate models in electronic form, and C. Conrad for comments. All figures were created with Generic Mapping Tools28. Some analysis was based on data services provided by the Plate Boundary Observatory operated by UNAVCO for EarthScope and supported by the National Science Foundation (NSF; EAR-0350028 and EAR-0732947). T.W.B. was partially supported by NSF/US Geological Survey Southern California Earthquake Center, as well as EAR-1215720 and EAR-1215757. A.R.L. was supported by EAR-0955909 and EAR-1358622.

Author information

Authors and Affiliations

  1. Department of Earth Sciences, University of Southern California, Los Angeles, 90089–0740, California, USA

    Thorsten W. Becker

  2. Department of Geology, Utah State University, Logan, 84322–4505, Utah, USA

    Anthony R. Lowry

  3. Department of Sciences, Università Roma Tre, Roma, 00146, Italy

    Claudio Faccenna

  4. Department of Earth and Planetary Sciences, The University of New Mexico, Albuquerque, 87131, New Mexico, USA

    Brandon Schmandt

  5. Scripps Institution of Oceanography, University of California San Diego, La Jolla, 92093–0225, California, USA

    Adrian Borsa

  6. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    Chunquan Yu

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Contributions

T.W.B. conducted the analysis and geodynamic modelling and wrote the paper with A.R.L. T.W.B., A.R.L. and C.F. designed the analysis and contributed to the writing. B.S. and C.Y. advised on geophysical constraints, A.B. provided assistance with GPS data, and all authors collaborated on interpretation of results.

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Correspondence to Thorsten W. Becker.

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Extended data figures and tables

Extended Data Figure 1 Maps of selected, additional scalar fields considered for the Molchan analysis in Fig. 2 and Extended Data Fig. 2.

a–c, Moho depth estimates from Levander and Miller3 (LM12S), Lowry and Pérez-Gussinyé11 (LP), and Shen et al.47 (CUB). d–f, ‘Lithosphere asthenosphere boundary’ (LAB) depth inferred from receiver functions by Levander and Miller3, shear wave version (d), horizontal normal strainrates based on GPS geodesy from Kreemer et al.29 (extension positive) (e), and vertical GPS rates, smoothed from the 2014 UNAVCO/PBO velocity release (pbo.final_frame.vel at ftp://data-out.unavco.org/pub/products/velocity/) with presumed outliers removed (f).

Extended Data Figure 2 Molchan skill20, S, for intraplate seismicity for an expanded set of models.

We show results for three Moho models: CUB47, LM12S3 (S wave version) and LP11 (as used in the main text, compare Extended Data Fig. 1a–c), estimates of LAB thickness from receiver functions (Extended Data Fig. 1d) and elastic thickness, and two kinds of GPE models, as in the main text, gradients thereof, geodynamic model predictions, and kinematic models for the western United States (Fig. 1). Dashed lines indicate the regions outside of which results are 95% significant. This more comprehensive analysis confirms the conclusions about relative model performance.

Extended Data Figure 3 Molchan error curves for prediction of all seismicity in the entire region of Fig. 1b.

Compare with Fig. 2a, which only considers seismicity outside the plate boundary zone as indicated in Fig. 1. Rate change of dynamic topography shows significant positive skill, even when including plate boundary seismicity.

Extended Data Figure 4 Correlation, r, between seismicity density (ϕ, Fig. 1b) and different models.

Obtained by even-area sampling of regions outside the plate boundary zone in Fig. 1, compare with Extended Data Fig. 2. Filled and open symbols are for linear (Pearson), r, and Spearman rank, rS, correlation, respectively. Dashed lines indicate the regions outside of which results are 95% significant, grey shading denotes approximate random density function distribution. Relative performance of Pearson correlation is consistent with results for skill (Extended Data Fig. 2), and Spearman rank shows some deviations, indicating lack of simple, linear relationships between ϕ and scalar fields.

Extended Data Figure 5 Wavelength-dependent correlation of seismicity and selected scalar fields.

Models considered: shear strain rates from geodesy (Fig. 1c); rate change of dynamic topography (Fig. 1f); gradients of Moho depth11; and GPE (Fig. 1d). Circles on right show the total correlation as in Extended Data Fig. 4. Solid, heavy lines and filled symbols are for linear (Pearson) correlation, and thin, dashed lines and open symbols are for Spearman rank correlation, respectively. Rate change of dynamic topography shows positive correlation with seismicity across most wavelengths. Shorter wavelengths, where the response of a rheologically complex lithosphere will be most relevant, emphasize the differences between r and rS seen in Extended Data Fig. 4.

Extended Data Figure 6 Illustrative, synthetic mantle flow models exploring dynamic topography and rate change thereof for simple, ad hoc temperature anomalies.

a–h, Bottom subplots show temperature anomalies and mantle flow velocities, top subplots show dynamic topography on the surface (left) and temporal change thereof (right) for four mantle density cases along profiles. a, b, Shallow, hot anomaly; c, d, shallow, cold anomaly; e, f, deep, hot anomaly; g, h, deep, cold anomaly. Note how rate change of dynamic topography is positive for both cold, sinking and hot, rising anomalies because of reduction of negative and increase of positive dynamic topography, respectively23,24.

Extended Data Figure 7 Multivariable regression analysis to best fit the seismicity density, evaluating a subset of the models of Extended Data Fig. 4.

The normalized contribution of each model vector, the importance wi , is indicated by filled and open symbols from a non-negative or regular least squares solution of equation (1), respectively. Results indicate that rate change of dynamic topography is the strongest driver of seismicity, with contributions from GPE, and modulated by Moho depth gradients and elastic thickness variations (compare with Extended Data Fig. 4).

Extended Data Figure 8 Wavelength-dependent correlation between vertical GPS rates (Extended Data Fig. 1f) and selected scalar fields.

For models and legend see Extended Data Fig. 5. Rate of topography change and shear strain rates show positive correlation with geodetically imaged uplift at wavelengths of ∼500…900 km, but rate change of dynamic topography is negatively correlated at longer wavelengths. Results indicate that rate change of dynamic topography may need to be understood more fully in context of a rheologically realistic model of lithospheric deformation, whereas geodetic uplift rates may be strongly affected by other signals, for example, climatic and hydrological.

Extended Data Figure 9 Molchan curves for mantle flow predictions for a range of tomographic models.

Flow modelling uses our reference model12 (compare with Fig. 2a and Extended Data Fig. 2), and older tomography38: SH11 (ref. 39) is a precursor of ref. 12; DNA10 a joint surface and body wave inversion by Obrebski et al.48; and NWUS-S an earlier, USArray-based shear wave tomography model by James et al.49. The best GPE model and smoothed seismicity are shown for reference. Older tomographic models substantiate our conclusions based on ref. 12; in particular SH11, which was found to bestpredict delay times40, has near-identical skill.

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Becker, T., Lowry, A., Faccenna, C. et al. Western US intermountain seismicity caused by changes in upper mantle flow. Nature 524, 458–461 (2015). https://doi.org/10.1038/nature14867

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