Skip to Main content Skip to Navigation
Journal articles

A noninvasive method for measuring the velocity of diffuse hydrothermal flow by tracking moving refractive index anomalies

Abstract : Diffuse flow velocimetry (DFV) is introduced as a new, noninvasive, optical technique for measuring the velocity of diffuse hydrothermal flow. The technique uses images of a motionless, random medium (e.g., rocks) obtained through the lens of a moving refraction index anomaly (e.g., a hot upwelling). The method works in two stages. First, the changes in apparent background deformation are calculated using particle image velocimetry (PIV). The deformation vectors are determined by a cross correlation of pixel intensities across consecutive images. Second, the 2-D velocity field is calculated by cross correlating the deformation vectors between consecutive PIV calculations. The accuracy of the method is tested with laboratory and numerical experiments of a laminar, axisymmetric plume in fluids with both constant and temperature-dependent viscosity. Results show that average RMS errors are ∼5%-7% and are most accurate in regions of pervasive apparent background deformation which is commonly encountered in regions of diffuse hydrothermal flow. The method is applied to a 25 s video sequence of diffuse flow from a small fracture captured during the Bathyluck'09 cruise to the Lucky Strike hydrothermal field (September 2009). The velocities of the ∼10°C-15°C effluent reach ∼5.5 cm/s, in strong agreement with previous measurements of diffuse flow. DFV is found to be most accurate for approximately 2-D flows where background objects have a small spatial scale, such as sand or gravel.
Document type :
Journal articles
Complete list of metadatas

Cited literature [34 references]  Display  Hide  Download
Contributor : Eva Fareau <>
Submitted on : Monday, September 17, 2018 - 3:54:37 PM
Last modification on : Thursday, September 17, 2020 - 3:06:33 AM
Long-term archiving on: : Tuesday, December 18, 2018 - 2:10:12 PM


Publisher files allowed on an open archive




Eric Mittelstaedt, Anne Davaille, Peter van Keken, Nuno Gracias, Javier Escartin. A noninvasive method for measuring the velocity of diffuse hydrothermal flow by tracking moving refractive index anomalies. Geochemistry, Geophysics, Geosystems, AGU and the Geochemical Society, 2010, 11 (10), ⟨10.1029/2010gc003227⟩. ⟨insu-01875633⟩



Record views


Files downloads