For the purpose of studying the impact of the 12 August 2021 South Sandwich tsunami in several locations around the world, a high-resolution digital elevation model (DEM) of Rupert’s Bay, Saint Helena Island (UK) has been built using three different types of data. They include: - The Global dataset 15 arcsec resolution GEBCO (2021) - The Global dataset 1 arcsec resolution SRTM (2013) - Digitized and georeferenced British Admiralty Nautical Chart 1771 – Saint Helena with approaches to Ascension Island (Edition 2019). The data showing the highest resolution has been kept in priority. The compilation of data has been interpolated to a regular spatial resolution of 0.00009° (~10m) between 5.71983815°W and 5.708260845°W and 15.91976089°S and 15.91137492°S using the krigging method. For more information about this method, see for example Oliver and Webster (1990). Two DEMs of lower resolution have been also built using the same methodology for nesting purpose used in tsunami simulations: - 0.0009° (~100 m): 5.744811692°W/5.697394505°W/15.92473881°S/15.89487881°S - 0.0045° (~500 m): 7.589583334°W/3.464583333°W/17.37291667°S/14.18124999°S DOI: https://doi.org/10.21420/YQF6-BV20 Cite data as: Roger, J. (2022). Digital Elevation Model of Rupert’s Bay, Saint Helena (UK). GNS Science. https://doi.org/10.21420/YQF6-BV20

Tsunami modelling with COMCOT and most other modelling software is based on a series of combined bathymetry and topography grids i.e. rectangular arrays of elevation/depth data, also called Digital Elevation Model (DEM) grids. These elevation modelling grids usually use Mean Sea Level as reference elevation level (zero elevation). These are prepared by processing and merging individual sources of elevation (e.g. LiDAR, topographic maps) and bathymetry (e.g. nautical charts, sonar) data into array grids. XYZ and ESRI ARC ASCII formats are two most commonly used data formats, compatible with most of GIS software. There are other proprietary formats for some simulation software. DOI: https://doi.org/10.21420/mhxg-7x67 Cite as: GNS Science. (2020). Elevation Modelling Grids [Data set]. GNS Science. https://doi.org/10.21420/MHXG-7X67

For the purpose of studying the impact of the 5 March 2021 Kermadec tsunami in Tutukaka Harbor, Whangarei, New Zealand, and its neighbourhood, a high-resolution digital elevation model (DEM) of Tutukaka Harbor has been built using two different types of data (Roger, 2022). These are: - Digitized and georeferenced British Admiralty Nautical Chart (Cape Brett to Paepae-o-Tu / Bream Tail, 1:90,000 – Id: NZ300521 and Tutukaka Harbour, 1:12,000 - Id: NZ552121) - The New Zealand 8 m DEM (LINZ, 2012) for the land part The compilation of data has been interpolated to a regular spatial resolution of 0.00009° (~10m) between 174.5233364°W and 174.5797705°W and -35.6252705°S and -35.5979928°S using the krigging method. For more information about this method, see for example Oliver and Webster (1990). DOI: https://doi.org/10.21420/AQBF-Q453 Cite when using the DEMs: Roger, J. (2022). Digital Elevation Model of Tutukaka Harbor and neighbourhood, Whangarei District, New Zealand [Data set]. GNS Science. https://doi.org/10.21420/AQBF-Q453

For the purpose of studying the impact of the 10 February 2021 South Matthew Island tsunami in the southwest Pacific Ocean, a set of three digital elevation models (DEM) of Norfolk Island, Australia, including a high-resolution focus on Sydney Bay (on the south coast of the island) has been built using three different types of data. They include: - The global dataset 15 arcsec resolution GEBCO (2020); - The global dataset 1 arcsec resolution SRTM (2013); - Norfolk Island LiDAR 0.57m DEM (Gallant and Petheram, 2020); - Digitized and georeferenced nautical chart of Norfolk Island (Australian Hydrographic Office, 2019) and related charts (Australian Hydrographic Office, 2009a, b, c, d). The data showing the highest resolution has been kept in priority. The compilation of data has been interpolated to a regular spatial resolution of 0.005° (~500 m) for the coarser grid, 0.0005° (~50 m) for the medium grid, and to 0.0001° (~10 m) for the grid over Sydney Bay. The data interpolation processes have done using the kriging method. For more information about this method, see for example Oliver and Webster (1990). DOI: https://doi.org/10.21420/H889-5393 Cite when using the DEMs: Roger, J. (2022). Digital Elevation Model of Norfolk Island and Sydney Bay, Australia. [Data set] GNS Science. Accessed on [insert date]. https://doi.org/10.21420/H889-5393.