THORSTEN W. BECKER
Department of Earth Sciences
University of Southern California
Los Angeles

Geodynamics research

Etna,Sicily, Sep 2005

[news] [teaching] [group] [publications] [CV] [downloads] [contact]
[geodynamics] [seismology] [fieldwork] [SEATREE] [downloads] [lab]
[anisotropy] [global mantle dynamics] [subduction] [western US]
  • Dynamic origin of surface topography

    A multi-project effort to contribute to our understanding of the origin of surface topography and the general mechanisms of mountain building and continental dynamics. We try to disentangle the effects of tectonics, erosion, and mantle flow (AKA dynamic topography) for building and destroying topography.

    • Yarce, Y., Monsalve, G. Becker, T. W., Cardona, A., Poveda, E., Alvira, D. OrdoƱez-Carmona, O.: Seismological observations in Northwestern South America: Evidence for two subduction segments, contrasting crustal thicknesses and upper mantle flow. Submitted to Tectonophys., 2014.
    • Sun, D., Miller, M. S., Holt, A. F., and Becker, T. W.: Hot upwelling conduit beneath the Atlas Mountains, Morocco. Submitted, 2014.
    • Faccenna, C., Becker, T. W., Miller, M. S., Serpelloni, E., Willett, S. D.: Isostasy, dynamic topography, and the elevation of the Apennines of Italy. Submitted to Earth Planet. Sci. Lett., 2014.
    • Faccenna, C., Becker, T. W., Auer, L., Billi, A., Boschi, L., Brun, J.-P., Capitanio, F. A., Funiciello, F., Horvath, F., Jolivet, L., Piromallo, C., Royden, L., Rossetti, F., and Serpelloni, E.: Mantle dynamics in the Mediterranean. Rev. Geophys., 52, doi:10.1002/2013RG000444, 2014. (PDF)
    • Becker, T. W., Faccenna, C., Humphreys, E. D., Lowry, A. R., and Miller, M. S.: Static and dynamic support of western U.S. topography. Earth Planet. Sci. Lett., doi:10.1016/j.epsl.2013.10.012, 2014. (PDF)
    • Miller, M. S. and Becker, T. W.: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains. Geology, 42, 35-38, 2014. (PDF)
    • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013. (PDF)
    • Ghosh, A., Becker, T. W., and Humphreys, E. D.: Dynamics of the North American continent. Geophys. J. Int., 194, 651-669, 2013. (PDF)
    • Boschi, L., Faccenna, C., and Becker, T. W.: Mantle structure and dynamic topography in the Mediterranean Basin. Geophys. Res. Lett., 37 (L20303), doi:10.1029/2010GL045001, 2010. (PDF)
    • Faccenna, C. and Becker, T. W.: Shaping mobile belts by small-scale convection. Nature, 465, 602-605, 2010. (PDF)


  • Plume-slab interactions, small scale convection, volcanism, and intraplate tectonics

    We evaluate the role of uppermost mantle convection in driving tectonic activity within plates and boundary zones in tectonically active continental regions such as the Mediterranean, the Middle East, the Horn of Africa, Tibet, and the western US.

    • Sun, D., Miller, M. S., Holt, A. F., and Becker, T. W.: Hot upwelling conduit beneath the Atlas Mountains, Morocco. Submitted, 2014.
    • Miller, M. S. and Becker, T. W.: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains. Geology, 42, 35-38, 2014. (PDF)
    • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013. (PDF)
    • Faccenna, C. and Becker, T. W.: Shaping mobile belts by small-scale convection. Nature, 465, 602-605, 2010. (PDF)
    • Faccenna, C., Becker, T. W., Lallemand, S., Lagabrielle, Y., Funiciello, F., and Piromallo, C.: Subduction-triggered magmatic pulses. Earth Planet. Sci. Lett., 209, 54-68, 2010.
    • Faccenna, C., Rossetti, F., Becker, T. W., Danesi, S., and Morelli, A: Recent extension driven by mantle upwelling at craton edge beneath the Admirality Mountains (Ross Sea, East Antarctica). Tectonics, 27, TC4015, doi:10.1029/2007TC002197, 2008. (PDF)
  • Dynamics of the western United States

    A multi-project effort to contribute to our understanding of Pacific-North America plate boundary processes on inter-seismic and geologic time-scales. We focus on forward models of stress and strain in the lithosphere based on geodetic, seismologic, and geodynamic information, and large-scale geodynamic models of mantle flow and subduction.

    • Schmandt, B., Jacobsen, S. D., Becker, T. W., Liu, Z., and Dueker, K. G.: Dehydration melting at the top of the lower mantle. Science, 334, 1265-1268, 2014. (PDF)
    • Becker, T. W., Faccenna, C., Humphreys, E. D., Lowry, A. R., and Miller, M. S.: Static and dynamic support of western U.S. topography. Earth Planet. Sci. Lett., 402, 234-246, 2014. (PDF)
    • Ghosh, A., Becker, T. W., and Humphreys, E. D.: Dynamics of the North American continent. Geophys. J. Int., 194, 651-669, 2013. (PDF)
    • Becker, T. W.: On recent seismic tomography for the western United States. Geochem., Geophys., Geosys., 13, Q01W10, doi:10.1029/2011GC003977, 2012. (PDF)
    • Platt, J. P. and Becker, T. W.: Kinematics of rotating panels of E-W faults in the San Andreas system: what can we tell from geodesy? Geophys. J. Int., 194, 1295-1301, 2013. (PDF)
    • Platt, J. P. and Becker, T. W.: Where is the real transform boundary in California? Geochem., Geophys., Geosys., 11(Q06013), doi:10.1029/2010GC003060, 2010. (PDF)
    • Platt, J. P., Kaus, B. J. P. and Becker, T. W.: The mechanics of continental transforms: An alternative approach with applications to the San Andreas system and the tectonics of California. Earth Planet. Sci. Lett., 274, 380-391, 2008. (PDF)
    • Fay, N. P. and T.W. Becker, and E. D. Humphreys: Southern California Modeling of Geodynamics in 3D (SMOG3D): Toward quantifying the state tectonic stress in the southern California crust, 2008 SCEC Annual Meeting Abstracts, 1-122, 2008.
    • Becker, T. W., Schulte-Pelkum, V., Blackman, D. K., Kellogg, J. B., and O'Connell, R. J.: Mantle flow under the western United States from shear wave splitting, Earth Planet. Sci. Lett., 247, 235-251, 2006. (PDF)
    • Becker, T. W., Hardebeck, J. L., and Anderson, G.: Constraints on fault slip rates of the southern California plate boundary from GPS velocity and stress inversions. Geophys. J. Int., 160, 634-650, 2005. (PDF).
    • Becker, T. W. and Schmeling, H.: Earthquake recurrence time variations with and without fault zone interactions. Geophys. J. Int., 135, 165-176, 1998. (PDF)


  • Global mantle dynamics

    • Generation of plate tectonics and mantle heterogeneity from convection

      We use spherical convection models in 3-D to study which rheological parameters lead to plate-tectonics like surface motions and are able to match tomographically inferred heterogeneity spectra self-consistently.

      • Foley, B. and Becker, T. W.: Generation of plate-like behavior and mantle heterogeneity from a spherical, visco-plastic convection model. Geochem., Geophys., Geosys., 10, Q08001, doi:10.1029/2009GC002378, 2009. (PDF)

        Top weekly download spot at G-Cubed and picked as highlighted image in August 2009 (G-Cubed "cover" from 08/2009).

      Also see our seismology inversions for vertical coherence of global structure and an improved global model of shear wave structure:

      • Auer, L., Boschi , L., Becker, T. W., Nissen-Meyer, T. and Giardini, D.: Savani: a variable-resolution whole-mantle model of anisotropic shear-velocity variations based on multiple datasets. J. Geophys. Res., 119, 3006-3034, doi:10.1002/2013JB010773, 2014.
      • Boschi, L. and Becker, T. W.: Vertical coherence in mantle heterogeneity from global seismic data. Geophys. Res. Lett., 38, (L20306), doi:10.1029/2011GL049281, 2011. (PDF)
    • Variability in plate tectonic heatflow over the Cenozoic and Earth's thermal evolution

      We use reconstructions of seafloor age and plate geometry variations over the Cenozoic to infer the character of mantle heat transport and plate tectonic cyclicity, exploring subduction probabilities and the nature of the seafloor age vs. area relationship.

      • Becker, T. W., Conrad, C. P., Buffett, B. and Müller, R. D.: Past and present seafloor age distributions and the temporal evolution of plate tectonic heat transport. Earth Planet. Sci. Lett., 278, , 233-242, 2009. (PDF)
      • Loyd, S. J., Becker, T. W., Conrad, C. P., Lithgow-Bertelloni, C., and Corsetti, F.A.: Time-variability in Cenozoic reconstructions of mantle heat flow: plate tectonic cycles and implications for Earth's thermal evolution Proceed. Nat. Acad. Sci., 104, 14266-14271, 2007. (PDF)
        • Popular science coverage: UPI (picked up by EarthTimes, Science Daily, First Science, Eureka Alert, PhysOrg, Terra Daily, NewsWise, Geology Times etc.), USC, USC College
    • Plume detection and the origin of EM1

      We analyze geodynamic and seismological models of the mantle and demonstrate that tomography images deep mantle plumes that connect to surface hotspots, if plume conduit distortion in the mantle wind is accounted for. We also analyze a range of geochemical and geophysical parameters to show that enriched mantle type of ocean island basalts (EM1 type OIBs) may be associated with a deep mantle source, along with mixing with shallow continental lithosphere material.

      • Konter, J. and Becker, T. W.: Shallow lithospheric contribution to mantle plumes revealed by integrating seismic and geochemical data. Geochem., Geophys., Geosys., 13, Q02004, doi:10.1029/2011GC003923, 2012. (PDF)
      • Boschi, L., Becker, T. W., and Steinberger, B.: On the statistical significance of correlations between synthetic mantle plumes and tomographic models. Physics Earth Planet. Int., 260, 230-238, 2008. (PDF)
      • Boschi, L., T. W. Becker, and B. Steinberger, Mantle plumes: Dynamic models and seismic images, Geochem. Geophys. Geosyst., 8, Q10006, doi:10.1029/2007GC001733, 2007. (PDF)

    • Plate velocities, mantle flow, and lithospheric deformation

      We have several ongoing collaborative efforts to refine our understanding of global and regional mantle circulation, subduction, what tractions might be expected to be transmitted to the lithosphere, why the plates move the way they do, and which geological processes might be associated with a deep mantle origin.

      • Schmandt, B., Jacobsen, S. D., Becker, T. W., Liu, Z., and Dueker, K. G.: Dehydration melting at the top of the lower mantle. Science, 334, 1265-1268, 2014. (PDF)
      • Yamato, Y., Husson, L., Becker, T. W., and Pedoja, K.: Passive margins getting squeezed in the mantle convection vice. Tectonics, 32, 1599-1570, doi: 10.1002/2013TC003375, 2013. (PDF)
      • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013. (PDF)
      • Faccenna, C., Becker, T. W., Conrad, C. P., and Husson, L.: Mountain building and mantle dynamics. Tectonics, 32, 80-93, doi:10.1029/2012TC003176, 2013. (PDF)
      • Faccenna, C., Becker, T. W., Lallemand, S., and Steinberger, B.: On the role of slab pull in the Cenozoic motion of the Pacific. Geophys. Res. Lett., 39, L03305, doi:10.1029/2011GL050155, 2012. (PDF)
      • Gérault, M. and Becker, T. W. and Kaus, B. J. K. and Faccenna, L. and Moresi, L. N. and Husson, L.: The role of slabs and oceanic plate geometry for the net rotation of the lithosphere, trench motions, and slab return flow. Geochem., Geophys., Geosys., 13, Q04001, doi:10.1029/2011GC003934, 2012. (PDF)
      • Becker, T. W. and Faccenna, C.: Mantle conveyor beneath the Tethyan collisional belt. Earth Planet. Sci. Lett., 310, 453-461, 2011. (PDF, suppl. mat.).
      • Becker, T. W. and Kawakatsu, H.: On the role of anisotropic viscosity for plate-scale flow. Geophys. Res. Lett., 38, L17307, doi:10.1029/2011GL048584, 2011. (PDF)
      • Faccenna, C. and Becker, T. W.: Shaping mobile belts by small-scale convection. Nature, 465, 602-605, 2010. (PDF)
      • Becker, T. W.: Fine-Scale Modeling of Global Plate Tectonics. Science, 329, 1020 - 1021, 2010. (PDF)
      • Ghosh, A., Becker, T. W., and Zhong, S.: Effects of lateral viscosity variations on the geoid. Geophys. Res. Lett., 37, L01301, doi:10.1029/2009GL040426, 2010. (PDF).
      • Bull, A. L., McNamara, A. K., Becker, T. W., and Ritsema, J.: Global scale models of the mantle flow field predicted by synthetic tomography models. Phys. Earth Planet. Int., 182, 129-138, 2010. (PDF)
      • Kaus, B, Liu, Y., Becker, T. W., Yuen, D., and Shi, Y.: Lithospheric stress-states predicted from long-term tectonic models: influence of rheology and possible application to Taiwan. J. Asian Earth Sci., 36, 119-134, 2009. (PDF)
      • Becker, T. W.: On the effect of temperature and strain-rate dependent viscosity on global mantle flow, net rotation, and plate-driving forces. Geophys. J. Int., 167, 943-957, 2006. (PDF)
      • Becker, T. W. and O'Connell, R. J.: Predicting plate motions with mantle circulation models, Geochemistry, Geophysics, Geosystems, 2(12), doi:10.1029/2001GC000171, 2001. (PDF)
      • Becker, T. W. and O'Connell, R. J.: Lithospheric stresses caused by mantle convection: the role of plate rheology (abstract) EOS Trans. AGU, 82, F, 2001. (PDF)
    • Thermal constraints on the survival of primitive blobs in the lower mantle

      We examine mantle blobs, a mantle convection model that could reconcile geochemical data with geophysical evidence for whole mantle convection. Our analytical model shows that stiff blobs could serve as a geochemical reservoir over geologically long timescales even if they were to heat up by means of enrichment in heat producing elements.

      • Becker, T. W., Kellogg, J. B., and O'Connell, R. J.: Thermal constraints on the survival of primitive blobs in the lower mantle. Earth Planet. Sci. Lett., 171, 351-365, 1999. (PDF)
    • A global comparison of seismologic and geodynamic mantle models

      We present comparisons between global seismological and geodynamic models of the Earth's mantle to help in the move from mapping to hypotheses testing. Our results are compatible with whole mantle convection with reorganization of flow at 660-km due to the viscosity jump and provide insights on time-dependent plate tectonics and the state of thermo-chemical convection in the mantle.

      • Steinberger, B., Torsvik, T. H., and Becker, T. W.: Subduction to the lower mantle - a comparison between geodynamic and tomographic models. Solid Earth, 3, 415-432, 2012. (PDF)
      • Becker, T. W. and Boschi, L.: A comparison of tomographic and geodynamic mantle models, Geochem., Geophys., Geosys., 3(1), 1003, doi:10.1029/2001GC000168, 2002. (PDF)

      Additional online material for Becker and Boschi (2002) can be found on the correlations between tomographic models page. All models from that paper, and a few newer ones, can be used directly as input for the hc global mantle flow program, as provided in the Solid Earth Research and Teaching Environment (SEATREE).

      • Milner, K., Becker, T. W., Boschi, L., Sain, J., Schorlemmer, D. and H. Waterhouse: The Solid Earth Research and Teaching Environment: a new software framework to share research tools in the classroom and across disciplines. Eos Trans. AGU, 90, 12, 2009. (PDF).
      • Waterhouse, H. D., K. Milner, T. W. Becker, J. Sain, and D. Schorlemmer: A Solid Earth Research and Teaching Environment, Opportunities and Challenges in Computational Geophysics workshop, Caltech, 2009. (PDF).
    • Global semi-analytical flow code benchmark

      Supported by CIG's Mantle Convection working group, I am coordinating a benchmark and recoding effort to establish a shared, modular and flexible implementation of a Hager & O'Connell (1981) type program for solving for velocities in the viscous mantle. Download instructions for the code are found here (under: hc). You can download the work plan with summary of results as PDF here; please send me an email if you would like to participate in this effort.

      As a product of this effort, a simple, modular, C-language implementation, hc, is available. HC is a module within the Solid Earth Research and Teaching (SEATREE) environment.
  • Subduction dynamics and lithospheric delamination

    • NSF-CD project Program to Investigate Convective Alboran Sea System Overturn (PICASSO)

      We were part of a multi-institutional, multi-disciplinary continental dynamics research effort funded by NSF-CD to study subduction dynamics and lithospheric delamination mechanisms in the westernmost terminus of the Tethyan collision.
      • Main PICASSO project web page
      • Geodynamics group project publications
        • Sun, D., Miller, M. S., Holt, A. F., and Becker, T. W.: Hot upwelling conduit beneath the Atlas Mountains, Morocco. Submitted, 2014.
        • Faccenna, C., Becker, T. W., Auer, L., Billi, A., Boschi, L., Brun, J.-P., Capitanio, F. A., Funiciello, F., Horvath, F., Jolivet, L., Piromallo, C., Royden, L., Rossetti, F., and Serpelloni, E.: Mantle dynamics in the Mediterranean. Rev. Geophys., 52, doi:10.1002/2013RG000444, 2014. (PDF)
        • Miller, M. S. and Becker, T. W.: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains. Geology, doi:10.1130/G34959, 2014. (PDF)
          • Miller, M. S. and Becker, T. W.: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains: Comment - Reply. Geology, 42, 338, 2014. (PDF)
          • Nature Geoscience highlight by Whitchuch
        • Alpert, L. A., Miller, M. S., Becker, T. W., and Allam, A. A.: Structure beneath the Alboran from geodynamic flow models and seismic anisotropy. J. Geophys. Res., 118, 4265--4277, doi:10.1002/jgrb.50309, 2013. (PDF)
        • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013. (PDF)
        • Miller, M. S., Allam, A. A., Becker, T. W., Di Leo, J., and Wookey, J.: Constraints on the geodynamic evolution of the westernmost Mediterranean and northwestern Africa from shear wave splitting analysis. Earth Planet. Sci. Lett., 375, 234-243, 2013. (PDF)
        • Becker, T. W. and Faccenna, C.: Mantle conveyor beneath the Tethyan collisional belt. Earth Planet. Sci. Lett., 310, 453-461, 2011. (PDF)
        • Faccenna, C. and Becker, T. W.: Shaping mobile belts by small-scale convection. Nature, 465, 602-605, 2010. (PDF)
    • Upper mantle slab dynamics

      We explore how regional and global subduction dynamics as well as the rheology of the lithosphere and mantle can affect slab morphologies, plate velocities, slab seismicity, and magmatism. Applications include the Caribbean, Mediterranean, Middle East, Taiwan, and the western Pacific domain.

      • Holt, A. F., Becker, T. W., and Buffett, B. A.: Subduction dynamics and overriding plate stress in thermo-mechanical subduction models. Submitted to Geophys. J. Int., 2014.
      • Faccenna, C., Becker, T. W., Auer, L., Billi, A., Boschi, L., Brun, J.-P., Capitanio, F. A., Funiciello, F., Horvath, F., Jolivet, L., Piromallo, C., Royden, L., Rossetti, F., and Serpelloni, E.: Mantle dynamics in the Mediterranean. Rev. Geophys., 52, doi:10.1002/2013RG000444, 2014. (PDF)
      • Alpert, L. A., Miller, M. S., Becker, T. W., and Allam, A. A.: Structure beneath the Alboran from geodynamic flow models and seismic anisotropy. J. Geophys. Res., 118, 4265--4277, doi:10.1002/jgrb.50309, 2013. (PDF)
      • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013.
      • Miller, M. S. and Becker, T. W.: Mantle flow deflected by interactions between subducted slabs and cratonic keels. Nature Geosc., 5, 726-730, 2012. (PDF)
      • Faccenna, C., Becker, T. W., Lallemand, S., and Steinberger, B.: On the role of slab pull in the Cenozoic motion of the Pacific. Geophys. Res. Lett., 39, L03305, doi:10.1029/2011GL050155, 2012. (PDF)
      • Gérault, M. and Becker, T. W. and Kaus, B. J. K. and Faccenna, L. and Moresi, L. N. and Husson, L.: The role of slabs and oceanic plate geometry for the net rotation of the lithosphere, trench motions, and slab return flow. Geochem., Geophys., Geosys., 13, Q04001, doi:10.1029/2011GC003934, 2012. (PDF)
      • Bailey, I. W., Alpert, L. A., Becker, T. W., and Miller, M. S.: Co-seismic deformation of deep slabs based on summed CMT data. J. Geophys. Res., 117, B04404, doi:10.1029/2011JB008943, 2012. (PDF)
      • Buffett, B. and Becker, T. W.: Bending stress and dissipation in subducted lithosphere. J. Geophys. Res., 117, B05413, doi:10.1029/2012JB009205, 2012. (PDF)
      • Boschi, L., Faccenna, C., and Becker, T. W.: Mantle structure and dynamic topography in the Mediterranean Basin. Geophys. Res. Lett., 37 (L20303), doi:10.1029/2010GL045001, 2010. (PDF)
      • Alpert, L. A., Becker, T. W., and Bailey, I. W.: Global slab deformation and centroid moment tensor constraints on viscosity. Geochem., Geophys. Geosys., 11,(Q12006), doi:10.1029/2010GC003301, 2010. (PDF)
      • Faccenna, C. and Becker, T. W.: Shaping mobile belts by small-scale convection. Nature, 465, 602-605, 2010. (PDF, News and views)
      • Faccenna, C., Becker, T. W., Lallemand, S., Lagabrielle, Y., Funiciello, F., and Piromallo, C.: Subduction-triggered magmatic pulses. A new class of plumes? Earth Planet. Sci. Lett., 209, 54-68, 2010. (PDF)
      • Becker, T. W. and Faccenna, C.: A review of the role of subduction dynamics for regional and global plate motions. In: Subduction Zone Geodynamics, Lallemand, S. and Funiciello, F. (eds), Int. J. Earth Sci., 3-34, 2009. (PDF)
      • Kaus, B, Liu, Y., Becker, T. W., Yuen, D., and Shi, Y.: Lithospheric stress-states predicted from long-term tectonic models: influence of rheology and possible application to Taiwan. J. Asian Earth Sci., 36, 119-134, 2009. (PDF)
      • Kaus, B. J. P., Steedman, C., and Becker, T. W.: From passive continental margin to mountain belt: insights from analytical and numerical models and application to Taiwan. Phys. Earth Planet. Int., 171, 25-251, 2008. (PDF)
      • Funiciello, F., Faccenna, C., Heuret, A., Di Giuseppe, E., Lallemand, S., and Becker, T. W.: Trench migration, net rotation and slab-mantle coupling. Earth Planet. Sci. Lett., 271, 233-240, 2008. (PDF)
      • Kaus B. J. P., Becker T. W.. A numerical study on the effects of surface boundary conditions and rheology on slab dynamics. Bolletino di Geofisica, 49(2), p. 177-182, 2008. (PDF)
      • Faccenna, C., Heuret, A., Funiciello, F., Lallemand, S., and Becker, T. W.: Predicting trench and plate motion from the dynamics of a strong slab. Earth Planet. Sci. Lett., 257, 29-36, 2007. (PDF)
      • Piromallo, C., Becker, T. W., Funiciello, F., and Faccenna, C.: Three-dimensional instantaneous mantle flow induced by subduction, Geophys. Res. Lett., 33, L08304, doi:10.1029/2005GL025390, 2006. (PDF)
      • Enns, A., Becker, T. W., and Schmeling, H.: The dynamics of subduction and trench migration for viscosity stratification. Geophys. J. Int., 160, 761-775, 2005. (PDF)
      • Faccenna, C., Becker, T. W., Lucente, F. P., Jolivet, L. and Rossetti, F.: History of Subduction and Back-arc Extension in the Central Mediterranean. Geophys. J. Int., 145, 809, 2001. (PDF)
      • Becker, T. W., Faccenna, C., O'Connell, R. J., and Giardini, D.: The development of slabs in the upper mantle: insights from experimental and laboratory experiments. J. Geophys. Res., 104, 15207, 1999. (PDF)

    • Subduction as imaged by structural seismology

      We investigate how the global subduction system is reflected in mantle heterogeneity as imaged structural seismology, and what this implies for time-dependent plate tectonics, mass transport from surface to depth, and back again, and thermo-chemical convection.

      • Schmandt, B., Jacobsen, S. D., Becker, T. W., Liu, Z., and Dueker, K. G.: Dehydration melting at the top of the lower mantle. Science, 334, 1265-1268, 2014. (PDF)
      • Faccenna, C., Becker, T. W., Conrad, C. P., and Husson, L.: Mountain building and mantle dynamics. Tectonics, 32, 1-15, doi:10.1029/2012TC003176, 2013. (PDF)
      • Steinberger, B., Torsvik, T. H., and Becker, T. W.: Subduction to the lower mantle - a comparison between geodynamic and tomographic models. Solid Earth, 3, 415-432, 2012. (PDF)
      • Boschi, L. and Becker, T. W.: Vertical coherence in mantle heterogeneity from global seismic data. Geophys. Res. Lett., 38, (L20306), doi:10.1029/2011GL049281, 2011. (PDF)
      • Becker, T. W. and Boschi, L.: A comparison of tomographic and geodynamic mantle models, Geochem., Geophys., Geosys., 3, 2001GC000168, 2002. (PDF)
    • Effect of elasticity on mantle convection

      We investigate the role of visco-elasticity for the formation of Rayleigh-Taylor type instabilities and lithospheric detachments.

      • Kaus, B. J. P. and Becker, T. W.: Effects of elasticity on the Rayleigh-Taylor instability: implications for large-scale geodynamics. Geophys. J. Int., 168, 843-862, 2007. (PDF)
  • Seismic anisotropy and upper mantle dynamics

    • Regional anisotropy and plate-lithosphere interactions

      We study regional shear wave splitting observations for the Caribbean, Alboran, and the western United States and interpret them in terms of upper mantle, small-scale convection and slab-keel interactions.

      • Faccenna, C., Becker, T. W., Auer, L., Billi, A., Boschi, L., Brun, J.-P., Capitanio, F. A., Funiciello, F., Horvath, F., Jolivet, L., Piromallo, C., Royden, L., Rossetti, F., and Serpelloni, E.: Mantle dynamics in the Mediterranean. Rev. Geophys., 52, doi:10.1002/2013RG000444, 2014. (PDF)
      • Miller, M. S. and Becker, T. W.: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains. Geology, 42, 35-38, 2014. (PDF)
      • Miller, M. S., Allam, A. A., Becker, T. W., Di Leo, J., and Wookey, J.: Constraints on the geodynamic evolution of the westernmost Mediterranean and northwestern Africa from shear wave splitting analysis. Earth Planet. Sci. Lett., 375, 234-243, 2013. (PDF)
      • Alpert, L. A., Miller, M. S., Becker, T. W., and Allam, A. A.: Structure beneath the Alboran from geodynamic flow models and seismic anisotropy. J. Geophys. Res., 118, 1-13, doi:10.1002/jgrb.50309, 2013. (PDF)
      • Faccenna, C., Becker, T. W., Jolivet, L., and Keskin, M.: Mantle convection in the Middle East: Reconciling Afar upwelling, Arabia indentation and Aegean trench rollback. Earth Planet. Sci. Lett., 375, 254-269, 2013. (PDF)
      • Miller, M. S. and Becker, T. W.: Mantle flow deflected by interactions between subducted slabs and cratonic keels. Nature Geosc., 5, 726-730, 2012. (PDF)
      • Becker, T. W., Schulte-Pelkum, V., Blackman, D. K., Kellogg, J. B., and O'Connell, R. J.: Mantle flow under the western United States from shear wave splitting, Earth Planet. Sci. Lett., 247, 235-251, 2006. (PDF)
    • Review articles on seismic anisotropy

      • Long, M. D. and Becker, T. W.: Mantle dynamics and seismic anisotropy. Earth Planet Sci. Lett., 297, Frontiers, 341-354, 2010. (PDF).
      • Becker, T. W.: Seismic anisotropy. In Encyclopedia of Solid Earth Geophysics, Gupta, H. (Ed.), doi: 10.1007/978-90-481-8702-7_51, p. 1070-1081, Springer, 2010. (HTML)
    • Radial anisotropy as a constraint for regional tectonics, mantle rheology, and volatile content

      We explore radial anisotropy by means of improved global and regional imaging and forward models based on stochastic and mantle flow computations. The geoynamic models are able to match both global radial anisotropy averages and most of the anomaly patterns. The mismatch between seismology and geodynamic reference, residual anisotropy, yields information on the frozen-in structure of the tectosphere and the volatile content and dynamics of the asthenosphere.

      • Auer, L., Boschi , L., Becker, T. W., Nissen-Meyer, T. and Giardini, D.: Savani: a variable-resolution whole-mantle model of anisotropic shear-velocity variations based on multiple datasets. J. Geophys. Res., 119, 3006-3034, doi:10.1002/2013JB010773, 2014. (PDF)
      • Schaefer, J. F., Boschi, L., Becker, T. W. and Kissling, E.: Radial anisotropy in the European mantle: Tomographic studies explored in terms of mantle flow. Geophys. Res. Lett., 38 (L23304), doi:10.1029/2011GL049687, 2011. (PDF).
      • Becker, T. W., Kustowski, B. and Ekström, G.: Radial seismic anisotropy as a constraint for upper mantle rheology. Earth Planet. Sci. Lett., 267, 213-237, 2008. (PDF)
    • Azimuthal anisotropy provides a speed limit for net rotation of the lithosphere

      We show that anisotropy constrains net rotations of the lithosphere to be smaller than in some hotspot reference frame models, and analyze different seismological models using generalized spherical harmonics. Geodynamics can provide an both heterogeneity power spectra and patterns. An NSF-Geophysics funded project.

      • Becker, T. W.: Azimuthal seismic anisotropy constrains net rotation of the lithosphere. Geophys. Res. Lett., 35, L05303, doi:10.1029/2007GL032928, 2008. (Correction: 2008GL033946, PDF)
      • Becker, T. W., Ekström, G., Boschi, L., and Woodhouse, J.: Length scales, patterns, and origin of azimuthal seismic anisotropy in the upper mantle as mapped by Rayleigh waves. Geophysical J. Int., 171 451-462, 2007. (PDF)
    • Length scales and origin of upper mantle anisotropy

      We analyze the lateral variations in anisotropic length scales as inferred from SKS splitting and azimuthal anisotropy tomography. Older continental regions appear more coherent than younger, geologically active units. We interpret this finding using surface waves and geodynamic models and explore different methods of predicting shear wave splitting from tomography

      • USC Geodynamics SKS splitting compilation, as used in Becker et al. (2012).
      • Becker, T. W., Lebedev, S., and Long, M. D.: On the relationship between azimuthal anisotropy from shear wave splitting and surface wave tomography. J. Geophys. Res., 117, B01306, doi:10.1029/2011JB008705, 2012. (PDF)
      • Becker, T. W., Browaeys, J. T., and Jordan, T. H.: Stochastic Analysis of Shear Wave Splitting Length Scales. Earth Planet. Sci. Lett., 259, 526-540, 2007. (PDF)
      • Becker, T. W., Ekström, G., Boschi, L., and Woodhouse, J.: Length scales, patterns, and origin of azimuthal seismic anisotropy in the upper mantle as mapped by Rayleigh waves. Geophysical J. Int., 171 451-462, 2007. (PDF)
    • Mantle flow, lattice preferred orientation (LPO) fabrics, and viscous anisotropy

      We study upper mantle fabrics from different mineral physics texturing models and mantle convection simulations with lateral viscosity variations. Texturing methods are found to differ strongly in terms of the treatment of recrystallization and predictions of mechanical anisotropy. Flow modeling results indicate that scaling relationships exist between hexagonal anisotropy parameters, and that natural samples follow the same trends as synthetics. We also explore the role of mechanical anisotropy for boundary layer flow. Previously NSF-CSEDI funded.

      • Becker, T. W., Conrad, C. P., Schaeffer, A. J., and Lebedev, S.: Origin of azimuthal seismic anisotropy in oceanic plates and mantle. Earth Planet. Sci. Lett., 401, 246-250, 2014. (PDF)
      • Becker, T. W. and Kawakatsu, H.: On the role of anisotropic viscosity for plate-scale flow. Geophys. Res. Lett., 38, L17307, doi:10.1029/2011GL048584, 2011. (PDF)
      • Castelnau, O., Blackman, D. K. and Becker, T. W.: Numerical simulations of texture development and associated rheological anisotropy in regions of complex mantle flow. Geophys. Res. Lett, 36, L12304, doi:10.1029/2009GL038027, 2009. (PDF)
      • Becker, T. W., Chevrot, S., Schulte-Pelkum, V., and Blackman, D. K.: Statistical properties of seismic anisotropy predicted by upper mantle geodynamic models. J. Geophys. Res., 111, B08309, doi:10.1029/2005JB004095, 2006. (PDF).
      • Becker, T. W., Kellogg, J. B., Ekström, G., and O'Connell, R. J.: Comparison of azimuthal seismic anisotropy from surface waves and finite-strain from global mantle-circulation models, Geophys. J. Int., 155, 696-714, 2003. (PDF)

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