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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L13304, doi:10.1029/2007GL029874, 2007

Global distribution of seamounts from ship-track bathymetry data

J. K. Hillier

Department of Earth Science, University of Cambridge, Cambridge, UK


A. B. Watts

Department of Earth Science, University of Oxford, Oxford, UK


Abstract

The distribution of submarine volcanoes, or seamounts, reflects melting within the Earth and how the magma generated ascends through the overlying lithosphere. Globally (±60° latitude), we use bathymetry data acquired along 39.5 × 106 km of ship tracks to find 201,055 probable seamounts, an order of magnitude more than previous counts across a wider height-range (0.1 < h < 6.7 km). In the North Pacific, seamounts' spatial distribution substantially reflects ridge-crest conditions, variable on timescales of 10 s of Ma and along-ridge distances of ∼1,000 km, rather than intra-plate hot-spot related volcanic activity. In the Atlantic, volcano numbers decrease, somewhat counter-intuitively, towards Iceland suggesting that abundant under-ridge melt may deter the formation of isolated volcanoes. Neither previously used empirical curve (exponential or power-law) describes the true size-frequency distribution of seamounts. Nevertheless, we predict 39 ± 1 × 103 large seamounts (h > 1 km), implying that ∼24,000 (60%) remain to be discovered.

Received 2 March 2007; accepted 31 May 2007; published 6 July 2007.

Keywords: seamout; volcanism; bathymetry.

Index Terms: 3045 Marine Geology and Geophysics: Seafloor morphology, geology, and geophysics; 3075 Marine Geology and Geophysics: Submarine tectonics and volcanism; 8178 Tectonophysics: Tectonics and magmatism; 8416 Volcanology: Mid-oceanic ridge processes (1032, 3614).

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Citation: Hillier, J. K., and A. B. Watts (2007), Global distribution of seamounts from ship-track bathymetry data, Geophys. Res. Lett., 34, L13304, doi:10.1029/2007GL029874.