thumbnail

Normalized velocity profiles of field-measured turbidity currents

Geology

By:
DOI: 10.1130/G30582.1

Links

Abstract

Multiple turbidity currents were recorded in two submarine canyons with maximum speed as high as 280 cm/s. For each individual turbidity current measured at a fixed station, its depth-averaged velocity typically decreased over time while its thickness increased. Some turbidity currents gained in speed as they traveled downcanyon, suggesting a possible self-accelerating process. The measured velocity profiles, first in this high resolution, allowed normalizations with various schemes. Empirical functions, obtained from laboratory experiments whose spatial and time scales are two to three orders of magnitude smaller, were found to represent the field data fairly well. The best similarity collapse of the velocity profiles was achieved when the streamwise velocity and the elevation were normalized respectively by the depth-averaged velocity and the turbidity current thickness. This normalization scheme can be generalized to an empirical function Y = exp(–αXβ) for the jet region above the velocity maximum. Confirming theoretical arguments and laboratory results of other studies, the field turbidity currents are Froude-supercritical.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Normalized velocity profiles of field-measured turbidity currents
Series title:
Geology
DOI:
10.1130/G30582.1
Volume
38
Issue:
6
Year Published:
2010
Language:
English
Publisher:
Geological Society of America
Publisher location:
Boulder, CO
Contributing office(s):
Pacific Coastal and Marine Science Center
Description:
4 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
563
Last page:
566
Online Only (Y/N):
N