Abstract
Crustal receiver functions have been calculated from 128 events for two three-component broadband seismomenters located on the south coast (FOMA) and in the central High Plateaux (ABPO) of Madagascar. For each station, crustal thickness and V p /V s ratio were estimated from H- κ plots. Self-consistent receiver functions from a smaller back-azimuthal range were then selected, stacked and inverted to determine shear wave velocity structure as a function of depth. These results were corroborated by guided forward modeling and by Monte Carlo error analysis. The crust is found to be thinner (39 ± 0.7 km) beneath the highland center of Madagascar compared to the coast (44 ± 1.6 km), which is the opposite of what would be expected for crustal isostasy, suggesting that present-day long wavelength topography is maintained, at least in part, dynamically. This inference of dynamic support is corroborated by shear wave splitting analyses at the same stations, which produce an overwhelming majority of null results (>96 %), as expected for vertical mantle flow or asthenospheric upwelling beneath the island. These findings suggest a sub-plate origin for dynamic support.
Similar content being viewed by others
References
Al-Hajri Y, White N, Fishwick S (2010) Scales of transient convective support beneath Africa. Geol 37(10):883–886
Bardintzeff J-M, Liégeois JP, Bonin B, Bellon H, Rasamimanana G (2009) Madagascar Volcanic provinces linked to the Gondwana break-up : geochemical and isotopic evidences for contrasting mantle sources. Gondwana Res 18:295–314
Bassin C, Laske G, Masters G (2000) The current limits of resolution for surface wave tomography in north america. EOS Transactions 81:F897
Bertil D, Regnoult J (1998) Seismotectonics of Madagascar. Tectonophysics 294:57–74
Bourgeat F, Petit M (1969) Contribution à l’étude des surfaces d’aplanissement sur les hautes–Terres centrales. Annales Géographiques 426:158–188
Bowman JR, Ando M (1987) Shear-wave splitting in the upper-mantle wedge above the Tonga subduction zone. Geophys J Int 88(1):25–41
Chaheire M, Chamassi M, Moussa A, Rakotondraibe T, Rakotozafy H, Rambolamanana G (2010) Modè,les de vitesses des ondes s à Madagascar par application de la fonction reécepteur. MadaGéo 15:29–33
Crosby AG, Fishwick S, White N (2010) Structure and evolution of the intracratonic Congo Basin. Geochemistry Geophysics Geosystems 11:Q06010
Davis MW, White NJ, Priestley KF, Baptie BJ, Tilmann FJ (2012) Crustal structure of the British Isles and its epeirogenic consequences. Geophys J Int 190:705–725
Eakin CM, Long MD (2013) Complex anisotropy beneath the Peruvian flat slab from frequency-dependent, multiple-phase shear wave splitting analysis. J Geophys Res 118(9):4794–4813
Eakin CM, Long MD, Wagner LS, Beck SL, Tavera H (2015) Upper mantle anisotropy beneath Peru from SKS splitting: constraints on flat slab dynamics and interaction with the Nazca Ridge. Earth Planet Sci Lett 412:152–162
Fishwick S, Bastow I (2011) Towards a better understanding of African topography, a review of passive-source seismic studies of the African crust and upper mantle. In: Van hinsbergen DJJ, Buiter SJH, Torsvik TH, Gaina C, Webb SJ (eds) The formation and evolution of Africa: a synopsis of 3.8 GA of Earth history, vol 357, pp 343–371
Fourno J-P, Roussel J (1994) Imaging of the Moho depth in Madagascar through the inversion of gravity data: geodynamic implications. Terra Nova 6:512–519
Kusky T, Toraman E, Raharimahefa T (2007) The Great Rift Valley of Madagascar: an extension of the Africa–SoMali diffuse plate boundary?. Gondwana Res 11:577–579
Kusky T, Toraman E, Raharimahefa T, Rasoazanamparany C (2010) Active tectonics of the alaotra–Ankay Graben System, Madagascar: possible extension of SoMalian–African diffusive plate boundary?. Gondwana Res 18:274– 294
Langston C (1979) Structure under Mount Rainier, Washington, inferred from teleseismic body waves. J Geophys Res 84(B9):4749–4762
Ni S, Tan E, Gurnis M, Helmberger D (2002) Sharp sides to the African superplume. Science 296:1850–1852
Panning MP, Romanowicz BA (2006) A three dimensional radially anisotropic model of shear velocity in the whole mantle. Geophys J Int 167:361–379
Pasaynos ME, Nyblade AA (2007) A top to bottom lithospheric study of Africa and Arabia. Tectonophysics 444:27–44
Paul JD, Roberts GG, White N (2014) The African landscape through space and time. Tectonics 33(6):898–935
Rakotondrainibe SA (1977) Contribution à l’étude de la sismicité de Madagascar. Thèse de Doctorat és-Sciences. Université Antananarivo, Madagascar
Rakotondraompiana S, Albouy Y, Piqué A. (1999) Lithospheric model of the Madagascar Island (western Indian Ocean): a new interpretation of the gravity data. Journal of African Earth Sciences 28:961–973
Rambolamanana G, Suhadolc P, Panza GF (1997) Simultaneous inversion of hypocentral parameters and structure velocity of the central region of Madagascar as a premise for the mitigation of seismic hazard in antananarivo. Pure Appl Geophys 149(4):707–730
Rindraharisaona EJ, Guidarellia M, Aoudiaa A, Rambolamanana G (2013) Earth structure and instrumental seismicity of Madagascar: implications on the seismotectonics. Tectonophysics 594:165–181
Roberts G, Paul J, White N, Winterbourne J (2012) Temporal and spatial evolution of dynamic support from river profiles: a framework for Madagascar. Geochemistry, Geophysics, Geosystems 13(4):040. doi:10.1029/2012GC004
Silver P, Chan W (1988) Implications for continental structure and evolution from seismic anisotropy. Nature 335:34–39
Simmons NA, Forte AM, Grand SP (2009) Joint seismic, geodynamic and mineral physical constraints on three-dimensional mantle heterogeneity: implications for the relative importance of thermal versus compositional heterogeneity. Geophys J Int 17:1284–1304
Stamps D, Calais E, Sarla E, Hartnady C, Nocquet J-M, Ebinger C, Fernandes R (2008) A kinematic model for the East African Rift. Geophysical Research Letters 35:L05,304
Wells NA, Andriamihaja B (1993) The initiation and growth of gullies in Madagascar: are humans to blame?. Geomorphology 8:1–46
De Wit M (2003) Madagascar: heads it’s a continent, tails it’s an island. Ann Rev Earth Planet Sci 31:213–248
Wüstefeld A, Bokelmann G, Zaroli C, Barrusol G (2008) Splitlab: A shear-wave splitting environment in Matlab. Computational Geoscience 34(5):515–528
Zhu L, Kanamori H (2000) Moho depth variation in southern California from teleseismic receiver functions. J Geophys Res 105:2969–2980
Acknowledgments
This research has benefited from discussions with A. Gilligan, G. Roberts, N. White and M. Davis, and from technical support from I. Frame. JDP is supported by BP Exploration. The comments of two anonymous reviewers greatly strengthened the manuscript. Figures were prepared using Inkscape and GMT4.2.0.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Paul, J.D., Eakin, C.M. Mantle upwelling beneath Madagascar: evidence from receiver function analysis and shear wave splitting. J Seismol 21, 825–836 (2017). https://doi.org/10.1007/s10950-016-9637-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10950-016-9637-x