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Browsing by Author "Dominey-Howes, D"

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Deposits, flow characteristics, and landscape change resulting from the September 2009 South Pacific Tsunami in the Samoan Islands
(Elsevier Science, 2011-07-01) Richmond, B; Buckley, M; Etienne, S; Chagué-Goff, C; Clark, K; Goff, JR; Dominey-Howes, D; Strotz, L
The September 29th 2009 tsunami caused widespread coastal modification within the islands of Samoa and northern Tonga in the South Pacific. Preliminary measurements indicate maximum runup values of around 17 m (Okal et al., 2010) and shore-normal inundation distances of up to similar to 620 m (Jaffe et al., 2010). Geological field reconnaissance studies were conducted as part of an UNESCO-IOC International Tsunami Survey Team survey within three weeks of the event in order to document the erosion, transport, and deposition of sediment by the tsunami. Data collected included: a) general morphology and geological characteristics of the coast, b) evidence of tsunami flow (inundation, flow depth and direction, wave height and runup), c) surficial and subsurface sediment samples including deposit thickness and extent, d) topographic mapping, and e) boulder size and location measurements. Four main types of sedimentary deposits were identified: a) gravel fields consisting mostly of isolated cobbles and boulders, b) sand sheets from a few to similar to 25 cm thick, c) piles of organic (mostly vegetation) and man-made material forming debris ramparts, and d) surface mud deposits that settled from suspension from standing water in the tsunami aftermath. Tsunami deposits within the reef system were not widespread, however, surficial changes to the reefs were observed. Published by Elsevier B.V.
Expanding the proxy toolkit to help identify past events: Lessons from the 2004 Indian Ocean Tsunami and the 2009 South Pacific Tsunami
(Elsevier, 2011-07-01) Chagué-Goff, C; Schneider, JL; Goff, JR; Dominey-Howes, D; Strotz, L
Some of the proxies used to identify palaeotsunamis are reviewed in light of new findings following the 2004 Indian Ocean Tsunami and the 2009 South Pacific Tsunami, and a revised toolkit provided. The new application of anisotropy of magnetic susceptibility (AMS) to the study of tsunami deposits and its usefulness to determine the hydrodynamic conditions during the emplacement of tsunami sequences, together with data from grain size analysis, are presented. The value of chemical proxies as indicators of saltwater inundation, associated marine shell and/or coral, high-energy depositional environment, and possible contamination, is demonstrated and issues of preservation addressed. We also provide new findings from detailed studies of heavy minerals. New information gathered during the UNESCO - International Oceanographic Commission (IOC) International Tsunami Survey of fine onshore sediments following the 2009 South Pacific Tsunami is presented, and includes grain size, chemical, diatom and foraminifera data. The tsunami deposit varied, ranging from fining-upward sand layers to thin sand layers overlain by a thick layer of organic debris and/or a mud cap. Grain size characteristics, chemical data and microfossil assemblages provide evidence for marine inundation from near shore, and changes in flow dynamics during the tsunami. (C) 2011 Elsevier B.V.
Holocene record of gradual, catastrophic and human influenced environmental change at Moashitu wetland, D'Urville Island, New Zealand
(Australian Metrological & Oceanographic Society, 2012-01-31) Cope, J; Chagué-Goff, C; Mooney, SD; Goff, JR; Zawadzki, A; Wong, HKY; Kilroy, C; Jacobsen, GE; Dominey-Howes, D
Active tectonism, sea level fluctuation and human arrival have moulded the present day physical environment of New Zealand. Coastal wetlands are recognised archives of Holocene environmental changes. By applying sedimentological, geochemical and chronological techniques to coastal wetlands, natural and anthropogenic changes can be observed. Moawhitu Wetland, located on D’Urville Island, New Zealand, is home to a Maori oral tradition that describes a giant wave destroying a community in the 15th century. Little geological work has been carried out to investigate the evidence of the event and no studies have researched the palaeoenvironmental history of the area. This research was therefore aimed at reconstructing the Holocene environmental record at Moawhitu Wetland to determine if there was evidence of severe changes to the landscape as described in Maori oral traditions. Three sedimentary sequences from Moawhitu Wetland were used to reconstruct a 7500 year record that incorporated gradual, catastrophic and human influenced changes. The record was established by using multiple sedimentary proxies (grainsize, organic matter content, geochemistry and mineralogy) at three different sites that were temporally aligned with dating techniques (14C and 210Pb) . Barrier formation, lake and wetland formation, erosion, human influences and a tsunami ~3000-3300 yr BP were identified in the sedimentary record. These changes were applied to a broader spatial context from which inferences of sea level rise, regional faulting and potential climate change were drawn. The central west coast of New Zealand has undergone an array of short and long term environmental changes throughout the Holocene and can be identified as an area susceptible to potential tsunami events.
Multi-proxy evidence for trans-Pacific tsunamis in the Hawai'ian Islands
(Elsevier, 2012-03-01) Chagué-Goff, C; Goff, JR; Nichol, SL; Dudley, W; Zawadzki, A; Bennett, JW; Mooney, SD; Fierro, D; Heijnis, H; Dominey-Howes, D; Courtney, C
The origin of two sand layers buried in Pololū wetland, on the northeast coast of the island of Hawai'i, was investigated using a multi-proxy approach, including radiometric dating, sedimentology, geochemistry, micropalaeontology, palynology and historical records. Based on 210Pb, 137Cs and pollen data, the lower sand unit extending 250 to 350 m inland is attributed to the 1946 Aleutian tsunami, while the upper sand unit was laid down by the 1957 Aleutian tsunami. Chronological information does not appear to support any link between these deposits and historical storm events. Furthermore, sedimentological, geochemical, diatom and pollen results suggest deposition of marine and near-beach sediments under high energy conditions typically associated with tsunami inundation. This work presents the first conclusive sedimentary evidence for distantly-generated tsunamis on the Hawai'ian Islands, opening the way for more comprehensive historical and palaeotsunami studies. Indeed, a brief review of archaeological data suggests that the Hawai'ian coast may have experienced similar large magnitude events in the past, from both local and distant sources. © 2012 Elsevier
Palaeotsunami magnitude, frequency and source (PMFS) modelling - progress in small steps
(International Union of Geodesy and Geophysics, 2011-07-03) Goff, JR; Dominey-Howes, D; Chagué-Goff, C
The study of contemporary tsunamis is a multi-disciplinary field. Not surprisingly, the same applies to palaeotsunamis. Collation and interpretation of data for palaeotsunamis however, is fraught with difficulties and currently most databases consist almost entirely of geological data. In an increasingly multi-disciplinary field this is severely limiting. We provide three examples of how multi-disciplinary data can be used to determine local, regional, and distantly sourced events. This is quite a remarkable dataset, but it throws up some interesting issues. To be able to effectively identify regional and distant palaeotsunami sources, we need to be able to compare and contrast between national databases. This can only happen if databases exist and are compatible – for example, are the criteria used for palaeotsunami interpretations consistent? Similarly, to be able to start commenting on the magnitude and frequency of palaeotsunamis from local, regional and distant sources, there need to be regional and national databases to refer to. Surprisingly, this is rarely the case. We highlight this issue with reference to palaeotsunami data from the Pacific Ocean. Palaeotsunami magnitude, frequency and source (PMFS) modelling can be and has been achievedalbeit with some caution. While it is acknowledged that any single palaeotsunami database will never be entirely complete and we may therefore never be fully able to determine the PMFS for any one region, this does not mean that is has no value. Far from it, after all every single historical database is also incomplete and they are however regularly used for probabilistic tsunami hazard modelling.
Palaeotsunamis in the Pacific Islands
(Elsevier, 2011-07-01) Goff, JR; Chagué-Goff, C; Dominey-Howes, D; McAdoo, B; Cronin, S; Bonté-Grapetin, M; Nichol, SL; Horrocks, M; Cisternas, M; Lamarche, G; Pelletier, B; Jaffe, BE; Dudley, W
The recent 29 September 2009 South Pacific and 27 February 2010 Chilean events are a graphic reminder that the tsunami hazard and risk for the Pacific Ocean region should not be forgotten. Pacific Islands Countries (PICs) generally have short ( < 150 years) historic records, which means that to understand their tsunami hazard and risk researchers must study evidence for prehistoric events. However, our current state of knowledge of palaeotsunamis in PICs as opposed to their circum-Pacific counterparts is minimal at best. We briefly outline the limited extent of our current knowledge and propose an innovative methodology for future research in the Pacific. Each PLC represents a point source of information in the Pacific Ocean and this would allow their palaeotsunami records to be treated akin to palaeo-DART (R) (Deep-ocean Assessment and Reporting of Tsunamis) buoys. Contemporaneous palaeotsunamis from local, regional and distant sources could be identified by using the spatial distribution of island records throughout the Pacific Ocean in conjunction with robust event chronologies. This would be highly innovative and, more importantly, would help provide the building blocks necessary to achieve more meaningful disaster risk reduction for PICs. (C) 2010 Elsevier B.V.
Progress in palaeotsunami research
(Elsevier, 2012-01-01) Goff, JR; Chagué-Goff, C; Nichol, SL; Jaffe, BE; Dominey-Howes, D
The study of palaeotsunamis preserved in the sedimentary record has developed over the past three decades to a point where the criteria used to identify these events range from well-tested and accepted to new methods yet to receive wide application. In this paper we review progress with the development of these criteria and identify opportunities for refinements and for extending their application to new settings. The emphasis here is on promoting the use of multiple proxies, selected to best match the context of the site or region of interest. Ultimately, this requires that palaeotsunami research must be a multidisciplinary endeavour and indeed, extend beyond the geological sciences of sedimentology and stratigraphy and, to include knowledge and approaches from field such as archaeology, anthropology and sociology. We also argue that in some instances, despite the use of multiple proxies, the evidence for tsunami inundation of a coast simply may not be preserved. (C) 2011 Elsevier B.V.
Records of tsunamis in the Indian Ocean with a particular focus on the northern end of the Bay of Bengal
(International Union of Geodesy and Geophysics, 2021-07-03) Alam, E; Dominey-Howes, D; Goff, JG; Chagué-Goff, C
The Indian Ocean was considered to have a low tsunami risk in comparison to the Pacific Ocean but the 2004 Indian Ocean tsunami has challenged that idea. Recently, debate has arisen regarding the potential tsunamigenic nature of the Northern Bay of Bengal region. To test this debate, we document historical tsunamis in the Indian Ocean region with a particular focus on the Northern Bay of Bengal (Latitude 15oS to 29oN and Longitude 70oE to 106oE) through detailed analysis of records contained within online global tsunami catalogues, regional tsunami databases, research papers, newspapers and so on. A total of 122 tsunamis are reported in the existing datasets. After completing a process of validity assessment, we recognised 29 definite tsunamis, 17 very probable tsunamis, 20 possible tsunamis, 30 doubtful tsunamis, 19 events that only caused a seiche or disturbance in an inland river and seven as erroneously reported events, which are cyclones or earthquakes. We record 13 reported tsunamis having occurred prior to 1800 AD and 109 tsunamis between 1800 AD and August 2010. Of the reported events, the tsunamis of 2 April 1762, 11 November 1842, 31 December 1881, 27 August 1883, 5 May 1930 and 24 December 2004 severely impacted the northern Bay of Bengal and adjoining regions. We encountered a number of challenges while recording data from the sourced documents, which include: incorrect and incomplete citations, difference in dates from different sources for the occurrence of the same event, contradictory descriptions of earthquakes, tsunamis and cyclones.
Reinterpretation of megatsunami inundation in Southeast Australia and the implications for palaeotsunami identification
(American Geophysical Union, 2011-12-05) Courtney, C; Dominey-Howes, D; Goff, JR; Chagué-Goff, C
The 2004 Indian Ocean tsunami resulted in a marked increase in concern regarding regions previously considered low risk of tsunami inundation. The southeast coast of Australia has a record suggesting low tsunami risk, with only 47 small tsunamis striking since European arrival. However, the controversial megatsunami hypothesis suggests patterns of massive inundation of the east Australian coast. Given the extreme vulnerability of the NSW coastline due to population concentration and the reliance on boulder deposit evidence, there is a need to provide thorough re-evaluation of the Australian tsunami risk. This re-examination has led to research at four back-beach locations on the south coast of New South Wales, located close to sites reported to contain evidence of megatsunami inundation. Analysis of stratigraphy, sediments, geochemistry and microfossils, plus an extensive radiocarbon chronology of these sites allows for a full reconstruction of the Holocene environments. This success highlights the importance of using multi-proxy diagnostic techniques in investigating potential tsunami inundation sites with relatively short historical records. In the case of NSW, no evidence of Holocene tsunamis has been identified, casting serious doubt on the existing understanding of tsunami risk on the NSW coast and the diagnostic criteria used for identifying tsunami deposits.
Small islands, big story. Opening up the palaeotsunami record of the Pacific
(International Union of Geodesy and Geophysics, 2011-07-01) Goff, JR; Chagué-Goff, C; Dominey-Howes, D
When one considers that the Pacific region accounts for 85% of known historical tsunamis worldwide, it is unsettling that we have only documented 11 Holocene palaeotsunamis throughout all Pacific island Countries. A recent addition to this dataset comes from a multi-proxy study of sites on Futuna Island, in the Wallis and Futuna archipelago. These sites preserved a record of two palaeotsunamis dated to around 1860-2000BP and c. 470BP. One of the most useful proxies in this study has been the archaeological data associated with occupations that immediately underlie the deposits associated with both palaeotsunamis, indicating that the study of palaeotsunamis is not solely in the domain of the geologist. While the palaeotsunami dataset is small, we collated the Futuna evidence with those on other islands in a first attempt to map the spatial and temporal distribution of past events over the last several thousand years throughout the entire Pacific region. We acknowledge that this is extraordinarily incomplete, but the method and the results are already providing interesting possible correlations. Both the 1860-2000BP and c. 470BP events identified on Futuna Island correlated with other data in the Pacific and start to point towards potential source areas. Ultimately, once a sufficient number of islands and data points have been studied, they will provide the essential baseline information needed for achieving more effective disaster risk reduction for PICs.
Tropical Cyclone Yasi and its predecessors
(Australian Tsunami Research Centre, 2011-02-01) Chagué-Goff, C; Goff, JR; Dominey-Howes, D; Nott, J; Sloss, CR; Shaw, W; Law, L
Tsunamis of the northeast Indian Ocean with a particular focus on the Bay of Bengal region - a synthesis and review
(Elsevier Science BV, 2012-08-01) Alam, E; Dominey-Howes, D; Chagué-Goff, C; Goff, JR
The 2004 Indian Ocean Tsunami (2004 IOT) challenged assumptions about the level of regional hazard. Significantly, there has been some debate about the hypothesis that the northern Bay of Bengal may be capable of generating large tsunamis similar to the 2004 IOT. To test this hypothesis, we documented historical and palaeotsunamis in the northeast Indian Ocean. Using multiple sources, we identified 135 purported tsunamis. After completing a process of validity assessment, we categorised 31 definite tsunamis, 27 probable tsunamis, 51 doubtful tsunamis and 20 events that only caused a seiche or disturbance in an inland river. Six of the purported events were identified as either cyclones or earthquakes without any associated tsunamis. Using the reported list of 135 events, we identified different tsunamigenic regions and explored the temporal distribution of past events, with the oldest event dated to around 38,000BC (although the dated material is most likely reworked and this was probably a Holocene event). The second oldest event dated to 3000-2000BC. Historical records indicate that only one definite tsunami, occurring in AD1762, was generated in the northern Bay of Bengal. We encountered a number of significant challenges in reviewing and analysing data contained within the documents and sources we consulted. Statistical analysis of tsunami data from AD1710 to AD2010 suggests that the occurrence of a tsunami affecting the coasts of Bangladesh and Myanmar is 0.99% in any given year, and 63% in a century. We recognise that this incomplete tsunami dataset limits the capacity to fully quantify the hazard. As such, we recommend further 'deep' archival research coupled with regional palaeotsunami studies to gain a more sophisticated understanding of the hazard. © 2012, Elsevier Ltd.

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