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Abstract Coastal boulder deposits (CBD) provide what are sometimes the only remaining signatures of wave inundation on rocky coastlines; in recent decades, CBD combined with initiation of motion (IoM) analyses have repeatedly been used as primary evidence to infer the existence of ancient tsunamis. However, IoM storm wave heights inferred by these studies have been shown to be highly inaccurate, bringing some inferences into question. This work develops a dimensionless framework to relate CBD properties with storm‐wave hindcasts and measurements, producing data‐driven relations between wave climate and boulder properties. We present an elevation‐density‐size‐inland distance‐wave height analysis for individual storm‐transported boulders which delineates the dynamic space where storm‐wave CBD occur. Testing these new relations against presumed tsunami CBD demonstrates that some fall well within the capabilities of storm events, suggesting that some previous studies might be fruitfully reexamined within the context of this new framework.
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How Does Coastal Gravel Get Sorted Under Stormy Longshore Transport?
Abstract Storm waves transport and sort coarse gravel along coasts. This fundamental process is important under changing sea‐levels and increased storm frequency and intensity. However, limited information on intra‐storm clast motion restricts theory development for coastal gravel sorting and coastal management of longshore transport. Here, we use smart boulders equipped with loggers recording underwater, real‐time, intra‐storm clast motion, and measured longshore displacement of varied‐mass marked boulders during storms. We utilize the unique setting of the Dead Sea shores where rapidly falling water levels allow isolating boulder transport during individual storms. Guided by these observations, we develop a new model quantifying the critical wave height for a certain clast mass mobilization. Then, we obtain an expression for the longshore clast displacement under the fluid‐induced pressure impulse of a given wave. Finally, we formulate the sorting enforced by wave‐height distributions during a storm, demonstrating how sorting is a direct manifestation of regional hydroclimatology.
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- Award ID(s):
- 1936258
- PAR ID:
- 10366659
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 48
- Issue:
- 21
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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