Tsunami hazard in south-eastern Australia: preliminary findings from palaeotsunami investigations on the NSW coast  

Authors / CoAuthors

Prendergast, A.L.

Abstract

Palaeotsunami investigations can enhance our understanding of tsunami hazard in the Australian region, providing a means of assessing future risk. Previous researchers have suggested that at least six large tsunami impacted the NSW coast during the Holocene, some with run-up in excess of +100 m asl and inundation of 10 km inland. However, this evidence is contentious as it focuses on poorly understood rocky shoreline features and proposes tsunami signatures that have not been described in other parts of the world. If such evidence is substantiated, it has profound implications for the tsunami preparedness of the NSW communities. This study focuses on late Holocene coastal sedimentary records from backshore environments in NSW to develop an assessment of whether catastrophic marine inundation such as tsunami played a significant role in coastal evolution. The advantages of studying backshore environments are that a more continuous sedimentary record is likely to be preserved than on rocky shorelines and an estimate of tsunami recurrence can be obtained if several tsunamigenic units are found in sequence. Fifty cores from sixteen coastal water bodies in southern and central NSW were studied for evidence of past tsunami inundation. Potentially tsunamigenic sediment horizons were identified in some water bodies, which may be a result of localised submarine slump-induced palaeotsunami. However the small size and discontinuous distribution of these sedimentary units does not support the theory of "mega-tsunami" inundation. If such "mega-tsunami" had occurred, definitive evidence for them should be preserved on a wider scale in the backshore sedimentary record. This suggests that previous research for mega-tsunami on the NSW coastline needs to be re-evaluated.

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nonGeographicDataset

eCat Id

65590

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Keywords

• External PublicationAbstract

( Theme )

• risk assessment

( Theme )

• tsunamis

( Theme )

• marine

• AU-NSW

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2008-01-01T00:00:00

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Australian Government Security ClassificationSystem    

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Creative Commons Attribution 4.0 International Licence    

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geoscientificInformation

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[-45.0, -30.0, 145.0, 155.0]

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