Imaging the Galápagos mantle plume with an unconventional application of floating seismometers.

Autor: Nolet G; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France. nolet@princeton.edu.; Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA. nolet@princeton.edu.; School of Ocean Science and Engineering, SUSTech, 518055, Shenzhen, China. nolet@princeton.edu., Hello Y; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France., Lee SV; Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL60208, USA., Bonnieux S; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France.; Université Côte d'Azur/CNRS, Laboratoire I3S, 06560, Sophia Antipolis, France., Ruiz MC; Instituto Geofísico, Escuela Politécnica Nacional, 2759, Quito, Ecuador., Pazmino NA; INOCAR, 5940, Guayaquil, Ecuador., Deschamps A; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France., Regnier MM; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France., Font Y; Université Côte d'Azur/CNRS/OCA/IRD, Géoazur, Sophia Antipolis, 06560, France., Chen YJ; School of Ocean Science and Engineering, SUSTech, 518055, Shenzhen, China., Simons FJ; Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2019 Feb 04; Vol. 9 (1), pp. 1326. Date of Electronic Publication: 2019 Feb 04.
DOI: 10.1038/s41598-018-36835-w
Abstrakt: We launched an array of nine freely floating submarine seismometers near the Galápagos islands, which remained operational for about two years. P and PKP waves from regional and teleseismic earthquakes were observed for a range of magnitudes. The signal-to-noise ratio is strongly influenced by the weather conditions and this determines the lowest magnitudes that can be observed. Waves from deep earthquakes are easier to pick, but the S/N ratio can be enhanced through filtering and the data cover earthquakes from all depths. We measured 580 arrival times for different raypaths. We show that even such a limited number of data gives a significant increase in resolution for the oceanic upper mantle. This is the first time an array of floating seismometers is used in seismic tomography to improve the resolution significantly where otherwise no seismic information is available. We show that the Galápagos Archipelago is underlain by a deep (about 1900 km) 200-300 km wide plume of high temperature, with a heat flux very much larger than predicted from its swell bathymetry. The decrease of the plume temperature anomaly towards the surface indicates that the Earth's mantle has a subadiabatic temperature gradient.
Databáze: MEDLINE
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