<div>The Abbot Point to Hydrographers Passage bathymetry survey was acquired for the Australian Hydrographic Office (AHO) onboard the RV Escape during the period 6 Oct 2020 – 16 Mar 2021. This was a contracted survey conducted for the Australian Hydrographic Office by iXblue Pty Ltd as part of the Hydroscheme Industry Partnership Program. The survey area encompases a section of Two-Way Route from Abbot Point through Hydrographers Passage QLD. Bathymetry data was acquired using a Kongsberg EM 2040, and processed using QPS QINSy. The dataset was then exported as a 30m resolution, 32 bit floating point GeoTIFF grid of the survey area.</div><div>This dataset is not to be used for navigational purposes.</div>

A mini-poster on GA's capability in tsunami hazard modelling.

A new methodology is proposed to estimate storm demand and dune recession by clustered and non-clustered events, to determine if the morphological response to storm clusters results in greater beach erosion than that from individual storms that have the same average recurrence interval (ARI) or return period. The method is tested using a numerical morphodynamic model that combines both cross-shore and longshore beach profile evolution processes, forced by a 2D wave transformation model, and is applied as an example within a 20 km long coastal cell at an erosion hotspot at Old Bar, NSW mid-north coast, Australia. Wave and water level data hindcast in previous modelling (Davies et al., 2017) were used to provide two thousand different synthetic wave and tide records of 100 years duration for input to a nested nearshore 2D SWAN model that provides wave conditions at the 12 m depth contour. An open-source shoreline evolution model was used with these wave conditions to model cross-shore and longshore beach profile evolution, and was calibrated and verified against long-term dune recession observations. After a 50 year model spin up, 50 years of storm demand (change in sub-aerial beach volume) and dune toe position were simulated and ranked to form natural estimators for the 50, 25, 16, 12.5 and 10 year return period of individual events, together with confidence limits. The storm demand analysis was then repeated to find the return period of clustered and non-clustered morphological events. Morphological clusters are defined here by considering the response of the beach, rather than the forcing, with a sensitivity analysis of the influence of different recovery thresholds between storms also investigated. The new analysis approach provides storm demand versus return period curves for the combined population of clustered and non-clustered events, as well as a curve for the total population of individual events. In this approach, non-clustered events can be interpreted as the response to isolated storms. For clustered and non-clustered morphological events the expected storm demand for a 50-year return period is approximately 25% greater than that for individual events. Alternatively, for clustered and non-clustered events the magnitude of the storm demand that occurs at a return period of 17 years is the same as that which occurs at a return period of 50 years for individual events. However, further analysis shows that for a 50-year return period, the expected storm demand for the population of non-clustered events is similar to that of the clustered events, although the size of the population of the latter is much greater. Hence, isolated storms can generate the same storm demand as storm clusters, but there is a much higher probability that a given storm demand is generated by a morphologically clustered event. Appeared online in Coastal Engineering Volume 168, September 2021.

In November, 2018 a workshop of experts sponsored by UNESCO’s Intergovernmental Oceanographic Commission was convened in Wellington, New Zealand. The meeting was organized by Working Group (WG) 1 of the Pacific Tsunami Warning System (PTWS). The meeting brought together fourteen experts from various disciplines and four different countries (New Zealand, Australia, USA and French Polynesia) and four observers from Pacific Island countries (Tonga, Fiji), with the objective of understanding the tsunami hazard posed by the Tonga-Kermadec trench, evaluating the current state of seismic and tsunami instrumentation in the region and assessing the level of readiness of at-risk populations. The meeting took place in the “Beehive” Annex to New Zealand’s Parliament building nearby the offices of the Ministry of Civil Defence and Emergency Management. The meeting was co-chaired by Mrs. Sarah-Jayne McCurrach (New Zealand) from the Ministry of Civil Defence and Emergency Management and Dr. Diego Arcas (USA) from NOAA’s Pacific Marine Environmental Laboratory. As one of the meeting objectives, the experts used their state-of-the-science knowledge of local tectonics to identify some of the potential, worst-case seismic scenarios for the Tonga-Kermadec trench. These scenarios were ranked as low, medium and high probability events by the same experts. While other non-seismic tsunamigenic scenarios were acknowledged, the level of uncertainty in the region, associated with the lack of instrumentation prevented the experts from identifying worse case scenarios for non-seismic sources. The present report synthesizes some of the findings of, and presents the seismic sources identified by the experts to pose the largest tsunami risk to nearby coastlines. In addition, workshop participants discussed existing gaps in scientific knowledge of local tectonics, including seismic and tsunami instrumentation of the trench and current level of tsunami readiness for at-risk populations, including real-time tsunami warnings. The results and conclusions of the meeting are presented in this report and some recommendations are summarized in the final section.

The NEAM Tsunami Hazard Model 2018 (NEAMTHM18) is a probabilistic hazard model for tsunamis generated by earthquakes. It covers the coastlines of the North-eastern Atlantic, the Mediterranean, and connected seas (NEAM). NEAMTHM18 was designed as a three-phase project. The first two phases were dedicated to the model development and hazard calculations, following a formalized decision-making process based on a multiple-expert protocol. The third phase was dedicated to documentation and dissemination. The hazard assessment workflow was structured in Steps and Levels. There are four Steps: Step-1) probabilistic earthquake model; Step-2) tsunami generation and modeling in deep water; Step-3) shoaling and inundation; Step-4) hazard aggregation and uncertainty quantification. Each Step includes a different number of Levels. Level-0 always describes the input data; the other Levels describe the intermediate results needed to proceed from one Step to another. Alternative datasets and models were considered in the implementation. The epistemic hazard uncertainty was quantified through an ensemble modeling technique accounting for alternative models’ weights and yielding a distribution of hazard curves represented by the mean and various percentiles. Hazard curves were calculated at 2,343 Points of Interest (POI) distributed at an average spacing of ∼20 km. Precalculated probability maps for five maximum inundation heights (MIH) and hazard intensity maps for five average return periods (ARP) were produced from hazard curves. In the entire NEAM Region, MIHs of several meters are rare but not impossible. Considering a 2% probability of exceedance in 50 years (ARP≈2,475 years), the POIs with MIH >5 m are fewer than 1% and are all in the Mediterranean on Libya, Egypt, Cyprus, and Greece coasts. In the North-East Atlantic, POIs with MIH >3 m are on the coasts of Mauritania and Gulf of Cadiz. Overall, 30% of the POIs have MIH >1 m. NEAMTHM18 results and documentation are available through the TSUMAPS-NEAM project website (http://www.tsumaps-neam.eu/), featuring an interactive web mapper. Although the NEAMTHM18 cannot substitute in-depth analyses at local scales, it represents the first action to start local and more detailed hazard and risk assessments and contributes to designing evacuation maps for tsunami early warning. Appeared online in Front. Earth Sci., 05 March 2021.

The Northern Approaches to Broome multibeam survey was acquired for the Australian Hydrographic Office (AHO) onboard the MV Bhagwan K during the period 05 August– 02 October 2020. This was a contracted survey conducted by EGS as part of the Hydroscheme Industry Partnership Program. The survey area encompasses the northern approaches to Broome, WA located between the Talboys Rock and Gantheaume Point, Western Australia. Bathymetry data was acquired using a Kongsberg EM2040D 200-400 kHz and processed using QPS QINSy 9.2.3 processing software. The dataset was then exported as a 30m resolution, 32 bit floating point GeoTIFF grid of the survey area. <BR>This dataset is not to be used for navigational purposes.

The Great North Channel Torres Strait Multibeam survey was acquired for the Australian Hydrographic Office (AHO) onboard the MV Offshore Guardian and MV Special Order during the period 04 February– 14 April 2021. This was a contracted survey conducted by Guardian Geomatics as part of the Hydroscheme Industry Partnership Program. The survey area encompasses the Great North East Channel of the Torres Strait located between the Stephens Island, Pearce Cay and Rennel Island, Queensland. Bathymetry data was acquired using a Kongsberg EM2040-07 and Norbit iWBMSh Stx 200-400 kHz and processed using CARIS HIPS & SIPS 11.3 processing software. The dataset was then exported as a 30m resolution, 32 bit floating point GeoTIFF grid of the survey area. <BR>This dataset is not to be used for navigational purposes.

<div>The Banks Strait Reference Surfaces bathymetry survey was acquired for the Australian Hydrographic Office (AHO) on 17 Dec 2021. This surface was created from a contracted national reference survey within Banks Strait to Cape Barren, TAS, collected for the purpose of calibrating multibeam echosounders.&nbsp;It was conducted for the Australian Hydrographic Office as part of the Hydroscheme Industry Partnership Program, acquired using Kongsberg EM 2040 MkII and Kongsberg EM 2040P, and processed using QPS Qimera. A grid in 0.5m resolution is provided for the surveyed site within this survey area in MSL, LAT and Ellipsoid vertical datum. The dataset was then exported as a 0.5m resolution, 32 bit floating point GeoTIFF grid of the survey area.</div><div>This dataset is not to be used for navigational purposes.</div>

The Solitary Islands Gumbaynggirr Yaegl MP bathymetry survey was acquired by the NSW government (Department of Planning and Environment – DPE) onboard the RV Bombora during the period 31 Aug 2022 – 31 Jul 2023, using DPE’s R2Sonic 2022 multibeam sonar. The survey was completed as part of the SeabedNSW program funded by NSW government through Coastal Reforms (>2015), HabMap Program funded through Marine Parks Authority (now under Marine Estate Management Authority) or through collaborations with partner agencies or institutions. The purpose of the project was to 1) provide a baseline dataset and 2) map the spatial distribution of seabed types. This dataset contains 32-bit floating point geotiff files of bathymetry and backscatter in 5m resolution for the study area, derived from the processed Hypack, R2Sonic GUI, POSView, POSPac, Qimera and FMGT software. General details on vessel setup, mobilisation and processing are provided at https://www.environment.nsw.gov.au/-/media/OEH/Corporate-Site/Documents/Research/Our-science-and-research/seabed-nsw-standard-operating-procedures-multibeam-surveying-190101.pdf with survey specific details in the Survey Report and DPIE Rigor Statement (can be provided upon request). This dataset is not to be used for navigational purposes.

<p>This resource contains multibeam bathymetry data for Bynoe Harbour collected by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government (Department of Environment and Natural Resources) during the period between 3 and 27 May 2016 on the RV Solander (survey SOL6432/GA04452). This project was made possible through offset funds provided by INPEX-led Ichthys LNG Project to Northern Territory Government Department of Environment and Natural Resources, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The intent of this four year (2014-2018) program is to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline data that enable the creation of thematic habitat maps that underpin marine resource management decisions. <p>The specific objectives of the survey were to: <p>1. Obtain high resolution geophysical (bathymetry) data for Bynoe Harbour; <p>2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for Bynoe Harbour; and <p>3. Collect tidal data for the survey area. Data acquired during the survey included: multibeam sonar bathymetry and acoustic backscatter; physical samples of seabed sediments, underwater photography and video of grab sample locations and oceanographic information including tidal data and sound velocity profiles. <p>This dataset comprises multibeam bathymetry data. A detailed account of the survey is provided in: Siwabessy, P.J.W., Smit, N., Atkinson, I., Dando, N., Harries, S., Howard, F.J.F., Li, J., Nicholas W.A., Picard, K., Radke, L.C., Tran, M., Williams, D. and Whiteway, T. 2016. Bynoe Harbour Marine Survey 2016: GA4452/SOL6432 – Post-survey report. Record 2017/04. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2017.004.