Repository logo
 
No Thumbnail Available
Publication

Boulder deposition during major tsunami events

Use this identifier to reference this record.

Advisor(s)

Abstract(s)

A remarkable accumulation of marine boulders located above the present spring tide level has occurred in two coastal lowlands of the Algarve (Portugal). The size-interval of the particles studied here is seldom reported in the literature in association with extreme events of coastal inundation, thus making this study of relevance to many other coasts worldwide. The spreads of boulders extend several hundred meters inland and well beyond the present landward limit of storm activity. The marine origin of the boulders is demonstrated by well-developed macro-bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves. The good state preservation of the fossils within the boulders indicates that abrasion duringtransport and redeposition was not significant. We envisage boulder deposition as having taken place during the Lisbon tsunami of ad 1755 through the simultaneous landward entrainment of coarse particles from nearshore followed by rapid shoreward suspended-dominated transport and non-graded redeposition that excluded significant sorting by weight or boulder dimensions. We use numerical hydrodynamic modeling of tsunami (and storm) waves to test the observational data on boulder dimensions (density, size, distribution) on the most likely processes of sediment deposition. This work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction. Copyright (C) 2011 John Wiley & Sons, Ltd.

Description

Keywords

Boulders Storm Tsunami Sediment transport Bioerosion 1755 Portugal High-energy events Southwestern Spain Sedimentary Record Lisbon earthquake Extreme waves Ionian coast Portugal Transport Algarve

Citation

COSTA, Pedro J. M.; ANDRADE, Cesar; FREITAS, Maria C; OLIVEIRAl, Maria A.; da SILVA, Carlos M.; OMIRA, Rachid; TABORDA, Rui; BAPTISTA, Maria A.; DAWSON, Alastair G. Boulder deposition during major tsunami events. Earth Surface Processes and Landforms. ISSN 0197-9337. Vol. 36, n.º 15 (2011) p. 2054-2068.

Research Projects

Organizational Units

Journal Issue

Publisher

Wiley-Blackwell

CC License