High-frequency sediment-level oscillations in the swash zone |
| |
Authors: | Asbury H. Sallenger Jr. Bruce M. Richmond |
| |
Affiliation: | U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, U.S.A. |
| |
Abstract: | Sediment-level oscillations with heights of about 6 cm and shore-normal lengths of order 10 m have been measured in the swash zone of a high-energy, coarse-sand beach. Crests of oscillations were shore parallel and continuous alongshore. The oscillations were of such low steepness (height-to-length ratio approximately 0.006) that they were difficult to detect visually. The period of oscillation ranged between 6 and 15 min and decreased landward across the swash zone. The sediment-level oscillations were progressive landward with an average migration rate in the middle to upper swash zone of 0.8 m min−1. Migration was caused mostly by erosion on the seaward flank of the crest of an oscillation during a period of net seaward sediment transport. Thus, the observed migration was a form migration landward rather than a migration involving net landward sediment transport. The observed sediment-level oscillations were different than sand waves or other swash-zone bedforms previously described. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|