Discoveries on coastal retrogressive breach failures inspired by failure of an underwater fixed platform

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2025-03-02 DOI:10.1016/j.margeo.2025.107530

Xiamei Man , William R. Dally , David P. Callaghan , Peter Nielsen

{"title":"Discoveries on coastal retrogressive breach failures inspired by failure of an underwater fixed platform","authors":"Xiamei Man , William R. Dally , David P. Callaghan , Peter Nielsen","doi":"10.1016/j.margeo.2025.107530","DOIUrl":null,"url":null,"abstract":"<div><div>Retrogressive breach failures (RBF) are submarine landslides that result in a nearly vertical sand wall above and below the water surface. Previous studies suggest a four-phase mechanism of RBFs, including triggering, propagation, termination, and recovery phases. There have been both laboratory and field studies on the later three phases, while the triggering mechanism of RBFs remain unknown given the event occurrence is unpredictable both spatially and temporally.</div><div>Amity Point on North Stradbroke Island, 37 km Northeast from Brisbane, Australia is a valuable coastal flow slide study site with frequent occurrence of approximately every two weeks (<span><span>Beinssen et al., 2014</span></span>) of them at a fixed location. Aiming at revealing the triggering mechanism of flow slides, an eight-meter-tall underwater tripod was manufactured and anchored on the seabed. The tripod location was designed to be fixed at a point with minimum bathymetry change during flow slide events referring to existing studies (<span><span>Beinssen et al., 2014</span></span>) with between 1.5 m and 2 m deep helical anchors. The tripod collapsed overnight by the undermining of two of the three helical anchors, including the 2 m deep anchor, by a significant underwater flow slide while there was minimal flow slide evidence on the beach.</div><div>The short lifespan of the tripod presents the complexity of RBFs (especially underwater) and the limitations of existing research. Underwater RBF events that do not propagate to the shore (or slightly erode the shore) occur more frequently than previous research reported (<span><span>Beinssen et al., 2014</span></span>). While it does not propagate to the shore, the event still erodes a significant amount of sand underwater. It indicates the triggering occurs at 10 m underwater or even deeper.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"484 ","pages":"Article 107530"},"PeriodicalIF":2.6000,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Marine Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0025322725000556","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

Retrogressive breach failures (RBF) are submarine landslides that result in a nearly vertical sand wall above and below the water surface. Previous studies suggest a four-phase mechanism of RBFs, including triggering, propagation, termination, and recovery phases. There have been both laboratory and field studies on the later three phases, while the triggering mechanism of RBFs remain unknown given the event occurrence is unpredictable both spatially and temporally.

Amity Point on North Stradbroke Island, 37 km Northeast from Brisbane, Australia is a valuable coastal flow slide study site with frequent occurrence of approximately every two weeks (Beinssen et al., 2014) of them at a fixed location. Aiming at revealing the triggering mechanism of flow slides, an eight-meter-tall underwater tripod was manufactured and anchored on the seabed. The tripod location was designed to be fixed at a point with minimum bathymetry change during flow slide events referring to existing studies (Beinssen et al., 2014) with between 1.5 m and 2 m deep helical anchors. The tripod collapsed overnight by the undermining of two of the three helical anchors, including the 2 m deep anchor, by a significant underwater flow slide while there was minimal flow slide evidence on the beach.

The short lifespan of the tripod presents the complexity of RBFs (especially underwater) and the limitations of existing research. Underwater RBF events that do not propagate to the shore (or slightly erode the shore) occur more frequently than previous research reported (Beinssen et al., 2014). While it does not propagate to the shore, the event still erodes a significant amount of sand underwater. It indicates the triggering occurs at 10 m underwater or even deeper.

查看原文本刊更多论文

求助全文

约1分钟内获得全文求助全文

来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.