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Geologic and geophysical mapping has been so far limited to the traditional single-method GIS-based mapping. A new approach combining integrated analysis of data on geology, gravity, topography and geomorphology is presented for regional characterization of the geophysical setting in Mongolia: the Gobi Altai Mountains, the Khangai Mountains and Khentii Mountains with surrounding areas. Nine new maps have been produced from the high-resolution datasets: GEBCO, gravity raster, USGS geological data and SRTM-90 DEM geomorphological grid. Methodology includes three tools for cartographic data visualization: i) Generic Mapping Tools (GMT), ii) R programming language (‘raster’ and ‘tmap’ libraries); iii) QGIS. The results demonstrated strong agreement between the estimated values in gravity and topography grids, distribution of geological units and provinces over the country and geomorphological landforms with respect to the mountain ranges: Altai, Khangai and Khentii Mountains. The highest values in the gravity anomalies correspond to the mountain ranges in the Altai Mountains and Khangai Mountains (

The high-energy region of Persian Gulf is investigated due to wave energy level, distribution direction, and stability over 40 years. For this purpose, 40-year ECMWF (ERA-Interim) wind data and GEBCO hydrographic data were used as the inputs for SWAN numerical model, and the wave characteristics and wave power were obtained. For detailed investigations, 15 points were considered to investigate in the high-energy area of the region which was introduced in previous research projects. A linear fit method between Buoy data and modeled data was used to increase the accuracy of the results. Finally, concluded that the northwest part of the middle region of Persian Gulf has had the highest average energy and power level, the southeast part is more sustainable and Optimum Hotspot Identifier and Sustainability Index for Wave Power parameters of this region have a higher value. Results showed that the wave power in the study region has an increasing trend by approximately a mean change rate of 0.03 (kW/m year), and there was an increase in energy level in the western and central parts of region during these 40 years. It was also found that the autumn and winter seasons had the lowest and highest level of power, respectively, and the amount of power in the autumn is approximately half that in the winter. The coefficient of determination (R2) is calculated and concluded that the wave power change rate correlates with a significant wave height change rate than the peak period change rate.

The characterization of estuarine hydrodynamics primarily depends on knowledge of the bathymetry and topography. Here, we present the first comprehensive, high-resolution dataset of the topography and bathymetry of the Amazon River estuary, the world's largest estuary. Our product is based on an innovative approach combining spaceborne remote sensing data, an extensive and processed river depth dataset, and auxiliary data. Our goal with this mapping is to promote the database usage in studies that require this information, such as hydrodynamic modeling or geomorphological assessments. Our twofold approach considered 500 000 sounding points digitized from 19 nautical charts for bathymetry estimation, in conjunction with a state-of-the-art topographic dataset based on remote sensing, encompassing intertidal flats, riverbanks, and adjacent floodplains. Finally, our estimate can be accessed in a unified 30 m resolution regular grid referenced to the Earth Gravitational Model 2008 (EGM08), complemented both landward and seaward by land (Multi-Error-Removed Improved-Terrain digital elevation model, MERIT DEM) and ocean (General Bathymetric Chart of the Oceans version 2020, GEBCO_2020) topographic data. Extensive validation against independent and spatially distributed data, from an airborne lidar survey, from ICESat-2 altimetric satellite data, and from various in situ surveys, shows a typical vertical accuracy of 7.2 m (riverbed) and 1.2 m (non-vegetated intertidal floodplains). The dataset is available at https://doi.org/10.17632/3g6b5ynrdb.2 (Fassoni-Andrade et al., 2021).

The coastal area of the Madura Strait stretches from Surabaya City to the east to Situbondo Regency and includes the southern part of Madura Island. The aim of this research is to map the suitability of the waters and coastal areas of the Madura Strait using GIS modeling. Mapping of the designation of the waters and coastal areas of the Madura Strait was carried out by overlaying spatial data covering bio-physical parameters including water transparency, pH, water substrate, temperature, salinity, and depth. The designation of water areas is divided into three classes, namely capture fisheries, tourism and conservation purposes. The spatial data used comes from several sources, namely the results of water quality surveys, Landsat 8 satellite imagery, bathymetry data / sea depth and Rupa Bumi Indonesia (RBI) maps at a scale of 1: 25,000. For water quality data comes from the results of a survey by the Marine and Fisheries Service of East Java Province in 2019 at 78 observation points in the waters of the Madura Strait. Water quality parameters used in GIS modeling are pH, salinity, brightness and temperature. The data for each observation point were then interpolated using the Kringing method. Landsat 8 satellite imagery is used to map the condition of the bottom substrate waters. Meanwhile, the depth data was downloaded from GEBCO (General Bathymetric Charts of the Oceans). The result of overlaying thematic maps shows that 37.69% (8586.69 km2) of the area of the Madura Strait is suitable for capture fisheries activities, then 10.28% (2341.02 km2) is suitable for marine tourism areas and 19.06 % (4343.4 km2) suitable for conservation areas. Meanwhile, 32.97% (7511.94 km2) can be used as conservation and tourism areas.

International audience; This paper examines spatial variations in the geomorphology of the Ninety East Ridge (NER), located in the Indian Ocean. The NER is an extraordinary long linear bathymetric feature with topography reflecting complex geophysical setting and geologic evolution. The research is based on a compilation of high-resolution bathymetric, geological, and gravity datasets clipped for the study area extent (65° - 107°E, 35°S - 21°N): General Bathymetric Chart of the Oceans (GEBCO), Earth Gravitational Model (EGM2008, EGM96). The submarine geomorphology of the NER was modeled by digitized cross-sectional profiles using Generic Mapping Tools (GMT). The availability of the method is explained by 1) the free datasets; 2) the open source GMT toolset; 3) the available tutorials of the GMT and the codes explained in this work. Three segments of the NER were selected, digitized, and modeled: 1) northern 89°E, 7°S to 90°E, 7°N; 2) central 88.4°E, 14.7°S to 88.8°E, 8.2°S; 3) southern 87.9°E, 17°S to 87.5°E, 27°S. Measured depths were visualized in graphs, compared, and statistically analyzed by the histograms. The northern segment has a steepness of 21.3° at the western slopes, and 14.5° at the eastern slope. The slopes on the eastern flank have dominant SE orientation. The central segment has a bell-shaped form, with the highest steepness comparing to the northern and southern segments. The eastern flank has a steepness of 49.5°. A local depression at a distance of 50 km off from the axis (90°E) continues parallel to the NER, with the shape of the narrow minor trench. The western slope has a steepness of 57.6°, decreasing to 15.6°. The southern segment has a dome-like shape form. Compared to the northern and central segments, it has a less pronounced ridge crest, with a steepness of 24.9° on the west. The eastern flank has a steepness of 36.8° until 70 km, gradually becoming steeper at 44.23°. A local minor trench structure can be seen on its eastern flank (100 km off the axis). This corresponds to the very narrow long topographic depressions stretching parallel to this segment of the NER at 90.5°E. The study contributes to regional geographic studies of Indian Ocean geomorphology and cartographic presentation of GMT functionality for marine research and oceanographic studies.

Mapping seafloor geomorphology is a complex task requiring the integration of advanced cartographic technologies and high-resolution spatial data. This paper provides a comparative geomorphological analysis of the Hellenic Trench (HT) and the Pliny Trench (PT) located in the Eastern Mediterranean Sea, southern Greece. These trenches were formed as a result of the tectonic plate subduction in the Eastern Mediterranean Sea: the northward motion of the African and Arabian plates, complicated by the regional geological settings, such as active faults and earthquakes, which resulted in their different geomorphological forms and bathymetric shapes. Technically, this paper presents an example of the advanced scripting mapping by scripting the cartographic toolset of Generic Mapping Tools (GMT), which performs mapping through shell scripts. The maps are based on the high-quality topographic, geological and geophysical data: GEBCO, EGM96, geoid, and marine free-air gravity fields. The GMT builds upon the modules used for data processing. The region was subsetted by ‘grdcut’, analysed by the Geospatial Data Abstraction Library (GDAL) (gdalinfo utility), and visualized by ‘grdimage’. Two segments of the trenches formed in a condition of varying geological and geophysical settings, have been modelled, visualized and compared, as representative cross-sections. As a result of the automated digitizing, spatial interpolation and sequential aggregating of GMT codes, the segments of the cross-sections were represented. The HT (Ionian segment) has an asymmetric one-sided shape; a steepness of 56.8° on the NE side and 7° on the SW flank. The PT has a more symmetric view; a steepness of 42.14° on its NW flank and 26.66° on its SE flank. The PT has a clear peak of the depths at -2600 to -2800 m and the most representative data range at -5000 to -6000 m. The HT has a bimodal data distribution with two peaks. The most frequent data for HT is -3200 m to -3400 m. Compared to PT, the HT is deeper. The histogram shows the peak of data for HT in the interval between -3200 to -3400 m (135 samples) while the PT shows the peak of data in the interval at -2600 to -2800 m (310 samples). Besides, 105 samples of the HT have depths exceeding 4000 m, while only 20 samples were recorded for PT in the same interval. This paper contributes to the geomorphological studies of the general Eastern Mediterranean Sea region, particularly relating to regional seafloor mapping of the Hellenic and Pliny trenches., Mapiranje geomorfologije morskoga dna složen je zadatak koji zahtijeva integraciju naprednih kartografskih tehnologija i prostornih podataka visoke rezolucije. Ovaj rad donosi usporednu geomorfološku analizu Helenskoga i Plinijskoga jarka smještenih u istočnome Sredozemlju, na jugu Grčke. Te su strukture nastale kao rezultat podvlačenja tektonske ploče, tj. kretanja afričke i arapske ploče prema sjeveru, usložnjenoga regionalnim geološkim postavkama poput aktivnih rasjeda i potresa, što je rezultiralo njihovim različitim geomorfološkim oblicima i batimetrijom. Prikazano je njihovo napredno kartiranje primjenom alata Generic Mapping Tools (GMT), koji koriste programske skripte. Karte se temelje na visokokvalitetnim topografskim, geološkim i geofizičkim podatcima, kao što su GEBCO, EGM96, geoid te gravitacijsko polje na razini mora. GMT se nadovezuje na module koji se koriste za obradu podataka. Područje je podijeljeno skriptom grdcut, a na temelju podataka iz zbirke apstraktnih geoprostornih podataka (GDAL) (skripta gdalinfo), te je na kraju vizualizirano (skripta grdimage). Dva dijela jarka oblikovana su u različitim geološkim i geofizičkim postavkama te su uspoređeni njihovi reprezentativni presjeci. Kao rezultat automatizirane digitalizacije, prostorne interpolacije i sekvencijalnoga agregiranja GMT kodova predstavljeni su segmenti presjeka. Helenski jarak (jonski segment) ima asimetričan jednostrani oblik, nagiba 56,8° na sjeveroistočnoj i 7° na jugozapadnoj strani. Plinijski je jarak simetričniji, nagiba 42,14° na SZ i 26,66° na JI boku. Plinijski jarak ima jasno izraženo tjeme od –2600 do –2800 m, a najreprezentativniji su podatci na –5000 do –6000 m. Helenski jarak ima bimodalnu distribuciju podataka s dvama tjemenima, a najčešće su dubine od –3200 do –3400 m. Taj je jarak dublji. Histogram prikazuje okupljanje podataka od –3200 do –3400 m, dok Plinijski (135 uzoraka) prikazuje maksimalne vrijednosti od –2600 do –2800 m (310 uzoraka). Osim toga, 105 uzoraka Helenskoga jarka ima dubine veće od –4000 m, dok je u istome intervalu za Plinijski zabilježeno samo 20 uzoraka. Članak doprinosi geomorfološkim studijama regije istočnoga Sredozemnog mora općenito i regionalnomu mapiranju morskoga dna, posebno Helenskoga i Plinijskoga jarka.

Advance in the visualization of the bathymetric and geological data from charted to digital maps and models opened the possibility to analyse data within Geographic Information System (GIS) functionalities. In this paper, bathymetric and geological properties of the Adriatic Sea were analysed using the General Bathymetric Chart of the Ocean (GEBCO) 2020 digital bathymetric model (DBM) and data from the European Marine Observation and Data Network (EMODnet). The bathymetric analysis includes depth statistics, area and volume calculation, hypsometry, and analysis of the heterogeneity of bathymetric data from the GEBCO 2020 DBM within the limits of the Adriatic defined by the International Hydrographic Organization (IHO) and 3 sub-basins delineated according to the bathymetry. The geological analysis includes seabed substrate map from EMODnet data and kilometre-scale seabed variability in the Adriatic. The GEBCO 2020 DBM shows that the Adriatic Sea is a shallow sea with a mean depth of -253 metres and over 50% of area shallower than 100 metres. The area of the Adriatic Sea is 138 516 km2 with a total volume of 35 521 km3. Patterns describing morphological variability coincide with the heterogeneity of the underlying source data of the GEBCO 2020 digital bathymetry model and major structures in the Adriatic Sea., Napredak u načinu prikaza batimetrijskih i geoloških podataka s papirnatih karata u digitalne podatke i modele otvorio je mogućnost manipulacije i analize podataka u digitalnome okruženju geografskih informacijskih sustava (GIS). U ovome radu analizirana su batimetrijska i geološka svojstva Jadranskoga mora s pomoću podataka digitalnoga batimetrijskoga modela General Bathymetric Chart of the Ocean (GEBCO) 2020 i Europske mreže za nadgledanje i prikupljanje podataka o moru (EMODnet). Batimetrijska analiza uključuje statistiku dubina, izračun površine i volumena, hipsometrijsku krivulju i analizu heterogenosti batimetrijskih podataka unutar modela GEBCO 2020 na području Jadranskoga mora čije je granice definirala Međunarodna organizacija za hidrografiju (IHO) te triju dijelova Jadranskoga bazena podijeljenih s obzirom na dubinu. Analiza geoloških svojstava obuhvaća prostornu preraspodjelu sedimenata na temelju podataka EMODnet mreže i varijabilnost terena u kilometarskoj razlučivosti na području Jadrana. Prema podatcima digitalnoga batimetrijskog modela GEBCO 2020 Jadransko je more plitko more s prosječnom dubinom od 253 m i više od 50 % površine pliće od 100 m. Površina Jadranskoga mora iznosi 138 516 km2 , a volumen 35 521 km3. Crte kojima je definirana varijabilnost terena poklapaju se s heterogenošću podataka na temelju kojih je izračunan model GEBCO i većim geomorfološkim strukturama u Jadranu.

The study presents an analysis of the sediment thickness compared with bathymetric and geophysical settings in the Bay of Bengal and Andaman Sea, Indian Ocean. It uses a combination of the high-resolution data: topographic GEBCO, satellite and marine gravity anomalies, EGM2008 geoid and GlobSed to visualize the correlation between relief, gravity and trends in continent-ocean sediment transport. The results include thematic maps and 3D model showing increased sediment thickness in the Bengal Fan (8,0 to 8,2 km) in NE direction with maximum in Ganges Fan (16,2 km), and southward decrease in the Andaman Sea from Irrawaddy river mouth (6-7 km) to the Strait of Malacca (1-2 km). All maps and 3D model have been plotted by Generic Mapping Tools (GMT) cartographic scripting toolset version 6.0.0.

In the past years, Indonesian people put more attention to Sunda Strait located between Java and Sumatra Islands, one of the busiest straits occupied with residential, recreational, fisheries, transportation, industrial and mining activities. Previous works on numerical modelling of tidal flow hydrodynamics of the Sunda Strait have resulted in good agreement against field data; however, the calibration of the models used was not described in detail. This paper presents the process of setting up the model, extensive calibration, validation and prediction of tidal currents for the Sunda Strait. A two-dimensional tidal-driven model is constructed using Delft3D, an open-source developed by Deltares. Four different bathymetry datasets, four different boundary condition configurations, and various bed roughness values are used, and their suitability in predicting tidal water level and current are investigated. It is found that changing the bathymetry and boundary conditions improve the model validation significantly. GEBCO_2019 bathymetry dataset outperforms the Batnas, even though it has a coarser resolution. For boundary conditions, the combination of water level and current velocity results in a better validation compares to using water level or current velocity only. However, the bed roughness shows an insignificant influence in predicting tidal conditions. The averaged current velocity is lower at the Southern than the Northern side of the strait due to a larger cross-section, consequence of deeper water. High tidal currents of magnitude around 2 m.s-1 are seen at the bottleneck of the strait.

The practice of assigning geographical names to undersea features on the bottom of the World Ocean and standardization of terms and names at the national and international levels are discussed. The development of underwater research technology, an increase in the number of sea expeditions, and the implementation of international projects—all this contributes to new discoveries. As for the Russian discoverers, their priority is enshrined in the names of more than 300 mountains, ridges, faults, and other undersea features of the World Ocean, included in the State Register of Geographical Names of the Russian Federation and the International Dictionary of Geographic Names (Gazetteer) of the General Bathymetric Ocean Chart (GEBCO). In the opinion of the authors of this article, it is necessary to intensify the work on collecting and approving names, many of which are recorded so far only in expedition reports and articles; to create national dictionaries, including regional ones; and to make wider use of Russian names in international publications.

Cartographic visualisation is a central concept in geoinformatics, and Generic Mapping Tools (GMT) functionality provides a variety of modules for effective mapping. However, due to its specific scripting approach, there is not enough reported experience of GMT mapping, comparing to traditional GIS. This contribution introduces steps that can be taken to perform cartographic mapping and modelling using GMT. Geographically, this paper investigates the Izu-Bonin Trench in the Pacific Ocean. The aim was to compare its geomorphology in two segments, and each was modelled by a series of profiles. The comparative analysis shows that the southern segment is deeper and is a more precisely V-shaped form with a steeper gradient slope. The northern part has an asymmetric slope with submarine terraces to the west and a straight shape to the east. The northern profile is based on 407 samples (13.5%) at depths of −5,600 to −5,800 m, followed by 304 samples at −5,800 to −6,000 m (10%). The southern histogram has a bimodal distribution with two peaks: 523 samples (20%) with depths of −5,800 to −6,000 m. The second peak (10%) is on the Bonin Ridge. The GMT proved to be an effective instrument for marine geological mapping, 3D and 2D modelling, statistical analysis and graphical plotting.

We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elevation tile format is used as the DEM format, which reduces the DEM data size. The PNG tile format implements client-based processing, and the DEM data are provided from different websites. In addition, the smart tile architecture is adopted, which enables on-demand simulation by adding a tile conversion process (i.e., a DEM selection process) during image drawing by using JavaScript. To demonstrate the system, we have employed three DEMs, i.e., the Geospatial Information Authority of Japan (GSI) map (~10-m resolution), the ASTER Global Digital Elevation Models (ASTER GDEM version 3) as global land area (~30-m resolution), and the General Bathymetric Chart of the Oceans as bathymetric data (~1000-m resolution). The ASTER Global Water Bodies Database is also used in the data selection process. The GSI provides their DEM in a PNG elevation tile format, and the other data are provided by the Geological Survey of Japan in PNG elevation tile format. We assume the current DEM sea level as 0 m, and the sea level can be changed to an arbitrary integer value (−10,000 to 10,000 m). Combining ASTER GDEM for land and GEBCO for sea makes it possible to target DEM of the whole earth. Moreover, it was shown that if a higher resolution DEM is available, it is possible to combine the higher resolution DEM in that area. The combining the PNG elevation tile format with the smart tile architecture demonstrates the possibilities of a client-based web processing service like that of the server-based OGC Web Processing Service.

The tsunami hazard posed by the Flores backarc thrust, which runs along the northern coast of the islands of Bali and Lombok, Indonesia, is poorly studied compared to the Sunda megathrust, situated ~250 km to the south of the islands. However, the 2018 Lombok earthquake sequence demonstrated the seismic potential of the western Flores Thrust when a fault ramp beneath the island of Lombok ruptured in two Mw 6.9 earthquakes. Although the uplift in these events mostly occurred below land, the sequence still generated 1–2.5 m-high local tsunamis along the northern coast of Lombok (Wibowo et al., 2021). Historical records show that the Flores fault system in the Lombok and Bali region has generated at least six ≥ Ms 6.5 tsunamigenic earthquakes since 1800 CE. Hence, it is important to assess the possible tsunami hazard represented by this fault system. Here, we focus on the submarine fault segment located between the islands of Lombok and Bali (below the Lombok Strait). We assess modeled tsunami patterns generated by fault slip in six earthquake scenarios (slip of 1–5 m, representing Mw 7.2–7.9+), with a focus on impacts on the capital cities of Mataram, Lombok and Denpasar, Bali, which lie on the coasts facing the strait. We use a geologically constrained earthquake model informed by the Lombok earthquake sequence (Lythgoe et al., 2021), together with a high-resolution bathymetry dataset developed by combining direct measurements from GEBCO with sounding measurements from the official nautical charts for Indonesia. Our results show that fault rupture in this region could trigger a tsunami reaching Mataram in

Coasts are areas of vitality because they host numerous activities worldwide. Despite their major importance, the knowledge of the main characteristics of the majority of coastal areas (e.g., coastal bathymetry) is still very limited. This is mainly due to the scarcity and lack of accurate measurements or observations, and the sparsity of coastal waters. Moreover, the high cost of performing observations with conventional methods does not allow expansion of the monitoring chain in different coastal areas. In this study, we suggest that the advent of remote sensing data (e.g., Sentinel 2A/B) and high performance computing could open a new perspective to overcome the lack of coastal observations. Indeed, previous research has shown that it is possible to derive large-scale coastal bathymetry from S-2 images. The large S-2 coverage, however, leads to a high computational cost when post-processing the images. Thus, we develop a methodology implemented on a High-Performance cluster (HPC) to derive the bathymetry from S-2 over the globe. In this paper, we describe the conceptualization and implementation of this methodology. Moreover, we will give a general overview of the generated bathymetry map for NA compared with the reference GEBCO global bathymetric product. Finally, we will highlight some hotspots by looking closely to their outputs.

Harmful algal bloom (HAB) events have alarmed authorities of human health that have caused severe illness and fatalities, death of marine organisms, and massive fish killings. This work aimed to perform the long short-term memory (LSTM) method and convolution neural network (CNN) method to predict the HAB events in the West Coast of Sabah. The results showed that this method could be used to predict satellite time series data in which previous studies only used vector data. This paper also could identify and predict whether there is HAB occurrence in the region. A chlorophyll a concentration (Chl-a, mg/L) variable was used as an HAB indicator, where the data were obtained from MODIS and GEBCO bathymetry. The eight-day dataset interval was from January 2003 to December 2018. The results obtained showed that the LSTM model outperformed the CNN model in terms of accuracy using RMSE and the correlation coefficient r as the statistical criteria.

Monitoring and assessing the distribution of economic areas in East Africa such as low and high income neighborhoods, has typically relied on the use of structured data and traditional survey approaches for collecting information such as questionnaires, interviews and field visits. These types of surveys are slow, costly and prone to human error. With the digital revolution, a lot of unstructured data is generated daily that is likely to contain useful proxy data for many economic variables. In this research we focus on satellite imagery data with applications in East Africa. Recently East African cities have been developing at a fast pace by building new infrastructure and constructing innovative economic zones. Moreover with increased urban population, cities have been expanding in multiple directions affecting the overall distribution of areas with economic activity. Automatic detection and classification of these areas could be used to inform a number of policies such as land usage and could also assist with policy enforcement monitoring. On the other hand, the distribution of different economic areas in a specific city could provide proxies for various economic development variables such as income distribution and poverty metrics. In this research, we apply deep learning techniques to satellite imagery to classify and assess the distribution of various economic areas of a specific region for urban planning. By benchmarking performance against various state-of-art models, results show that the proposed deep learning techniques yielded superior performance with an f1-score of 99%.

International audience; Scripting cartographic technique is a new method of geospatial data visualization – especially with thematic mapping such as geomorphological models. The purpose of this study was to explore the use of Generic Mapping Tools (GMT) and R for geomorphological and topographic mapping of Serbia using free open datasets (DEM, SRTM/ GEBCO, OpenStreetMap). Current trend in education and research of distance-based and online-based education suggests that application of free high-resolution data for modelling and mapping by open source cartographic toolsets are more likely to result in deep geospa- tial analysis of the geomorphology of Balkans with associated geographic phenomena: hydrology, soils, vegetation, geology. Presented fragments of scripts aim to demonstrate the technical usage of R and GMT coding in cartographic workflow with a case study on Serbia. Using qualitative descriptive cartographic approach to visualize the slope, aspect and terrain elevations over the country and the ‘raster’ package provided by R, it was found that the geomorphology of Serbia spatially differs in southern and northern parts of the country re- sulting in regional geologic evolution and tectonic dynamics of the Balkan formation. The presented maps portrayed general distribution of the landforms in Serbian region of Balkans. The research contributes to the methodological development and testing of the cartographic techniques as well as geomorphological and environmental studies of Serbia.; Скриптна картографска техника је нов метод визуелизације гео- спацијалних података – посебно са тематским мапирањем као што су геоморфо- лошки модели. Циљ овог проучавања је истраживање употребе Генеричког алата за мапирање (енгл. GMT) и R за геоморфолошко и топографско мапирање Србије користећи слободне отворене скупове података (DEM, SRTM/GEBCO, OpenStreet- Map). Актуелан тренд у образовању и истраживање наставе на даљину и онлајн наставе указује на то да примена слободних података високе резолуције за моде- ловање и мапирање путем картографског алата из отворених извора, највероват- није резултира дубоком геоспацијалном анализом геоморфологије Балкана са повезаним географским феноменима: хидрологија, земљишта, вегетација, гео- логија. Приказани фрагменти скрипта имају за циљ да демонстрирају техничку употребу R и GMT кодирања у картографском процесу рада где је Србија у фоку- су истраживања случаја. Користећи квалитативни описни картографски приступ да би се визуелизовали нагиб, положај и издизање земљишта широм земље и „растер” пакет обезбеђен путем R, откривено је да се геоморфологија Србије про- сторно разликује у јужним и северним деловима земље што резултира регионал- ном геолошком еволуцијом и тектонском динамиком балканске формације. При- казане мапе показале су генералну дистрибуцију рељефа у делу Балкана у којем је Србија. Истраживање доприноси методолошком развоју и тестирању карто- графских техника као и геоморфолошким изучавањима и изучавањима животне средине у Србији.

The potential tsunami hazard for atoll islands inside the South China Sea (SCS) has not been investigated previously. In this study, we assess the tsunami hazard for the Xisha Archipelago using a deterministic approach. The tsunami source considered in this study is hypothesized earthquakes in the Manila subduction zone. We employ COMCOT (COrnell Multi-grid Coupled Tsunami model) for tsunami simulations. Different with previous deterministic assessments, our study investigates the uncertainties caused by bathymetric resolution and rupture complexities (here refers to rupture speed and direction variations related to fault geometry complexity). Comparison between results of different resolution suggests that coarser grids may over/underestimate tsunami hazards around mid-ocean atoll islands and this depends on the surrounding bathymetry. But results of different datasets show that GEBCO may lead to a lower result than the multibeam data. We also investigate the uncertainties caused by different rupture speed and direction, which are highly affected by subducting seamounts/ridge. Different rupture direction will shift the hardest hit locations to areas, which are possibly underestimated in cases of instantaneous ruptures. Also, the distribution of slip and location of the rupture zone can affect the local tsunami wave height significantly. We suggest that near-island high-resolution bathymetric data and dynamic rupture process should be considered in future tsunami hazard assessment in locations with similar geological structures.

This study aims to look at the conditions and characteristics of significant wave height and its relationship to wind velocity in the Makassar Strait in 2017. The data used in this study are bathymetry data from GEBCO with a resolution of 30 seconds, significant wave height data (Hs) with a resolution of 0.25 x 0.25 as well as wind velocity and direction with a resolution of 0.25 x 0.25 which are secondary data results from the European Center for Medium-Range Weather Forecasts (ECMWF) with a span of one year in 2017. The method used in this research is an analysis of the energy spectrum of significant wave height using Fast Fourier Transform. In addition, wind velocity and direction are processed by using GrADS software to see the visual conditions. Based on this study, it can be concluded that wind velocity is strongly associated with significant wave height values. This can be seen at each sample point in the Makassar Strait, where when the value of wind velocity is high, the value of significant wave height has the same conditions, and vice versa. The wind velocity value has a maximum value in the Makassar Strait during the east season with a value of more than 4.5 m/s. The highest energy spectrum occurs at point 3 in the Makassar Strait, which is 7303 m2 with a period of 6 months.

Access to reliable and accurate bathymetric data is fundamental to many marine activities. This paper proposes a merge-normalization (MN) method that is suitable for multisource bathymetric data fusion in deep ocean areas, to solve the problem of difficult to integrate high-precision digital bathymetric model (DBM) for complex sources and various resolutions of global deep ocean bathymetric data. Then we apply it to the DBM construction of the Mariana Trench. The method combines multibeam, single-beam, and electronic navigational chart data with Shuttle Radar Topography Mission (SRTM) dataset by using the workflow of merging and normalizing, which can fill the data gaps while preserving topographic details in high-resolution bathymetric data. Compared with the widely used General Bathymetric Chart of the Oceans (GEBCO) dataset, the Mariana Trench dataset constructed in this study demonstrated improved accuracy, resolution, and topographic detail, highlighting the value of the application of the method and of its development potential.

The author would like to thank James H Churchill, Larry Pratt, and Jim Thomas for the discussions and help. The topography data are derived from General Bathymetric Chart of the Oceans (GEBCO: https://www.gebco.net/). The initial salinity and temperature is extracted from World Ocean Atlas 2009 (WOA09: https://www.nodc.noaa.gov/OC5/WOA09/pr_woa09.html). The barotropic tidal boundary currents and the spatial distribution of elevation amplitudes and phases are derived from TPXO 7.2 inverse model (http://volkov.oce.orst.edu/tides/global.html). The MITgcm model output data files, sea level data from gauges, and mooring data can be found at Figshare (https://figshare.com/projects/Data_for_B2018JC013970_bc_redsea/57407). The research reported in this manuscript was supported by King Abdullah University of Science and Technology. This research made use of the resources from the Supercomputing Laboratory and/or computer clusters at King Abdullah University of Science and Technology.

The topography data is derived from General Bathymetric Chart of the Oceans (GEBCO: https://www.gebco.net/). The open boundary conditions are extracted from the Estimating the Circulation and Climate of the Ocean (ECCO) product (https://ecco.jpl.nasa.gov/products/). The data supporting the analysis presented here can be found at Figshare (https://figshare.com/articles/Data for 2018JC014531R/7243184/). The research reported in this manuscript is supported by King Abdullah University of Science and Technology (KAUST) and made use of the resources of the Supercomputing Laboratory and computer clusters at KAUST.

For the first time, HY-2A/GM-derived gravity anomalies determined with the least-squares collocation method and ship-borne bathymetry released from the National Centers for Environmental Information (NCEI) are used to predict bathymetry with the gravity-geologic method (GGM) over three test areas located in the South China Sea (105–122°E, 2–26°N). The iterative method is used to determine density contrasts (1.4, 1.5, and 1.6 g/cm3) between seawater and ocean bottom topography, improving the accuracy of GGM bathymetry. The results show that GGM bathymetry is the closest to ship-borne bathymetry at check points, followed by SRTM15+V2.0 model and GEBCO 2020 model. It is found that in a certain range, the relative accuracy of GGM bathymetry tends to improve with the increase of depth. Different geological structures affect the accuracy of GGM bathymetry. In addition, the influences of gravity anomalies and data processing method on GGM bathymetry are analyzed. Our assessment result suggests that GGM can be widely applied to bathymetry prediction and that HY-2A/GM-derived gravity data are feasible with good results in calculating ocean depth.

SEA-KIT USV Maxlimer successfully carried out a 22 day (24hrs per day), uncrewed survey operation offshore the United Kingdom in July-August 2020. The uncrewed vessel was controlled and manoeuvred from an operation room based in Essex, UK, while the data acquisition was performed by alumni of the Nippon Foundation/GEBCO Training Program, through the Map the Gaps NPO, spread across 10 countries. One of the main objectives of the trans-ocean survey was to test the remote survey capabilities through satellite communications, and also promote the contribution to seafloor mapping. CARIS Onboard, incorporating the new Sonar Noise Classifier tool via the CARIS Mira AI platform, was deployed to autonomously process the survey data in real-time, and provide products that could be streamed daily from SEA-KIT to ensure operations were successful and to help train the classifier as required. The data was post-processed with CARIS HIPS and SIPS using conventional and Ai techniques, and gridded at 10 m. The collected data size was 52.2 GB, surveyed area depth range from 57m to 1362 with 470m mean depth and around 900 km2 was totally covered. CARIS Mira AI with traditional QC approach reduced data processing time to 77% regarding the conventional path.The high-resolution bathymetric dataset provided the first detailed picture of the Brenot Spur, adjacent to Dangeart Canyon. Three major submarine canyon systems can be identified, cross-cutting the continental shelf nearly perpendicularly. The main axis of the first canyon, located at the far northern part of the surveyed area, is oriented NE-SW and becomes wider downstream. Both of the flanks are highly carved by gullies and tributaries, especially along the northern flank, where a complex system is developed depicting well-developed amphitheatric heads, indicating retrogressive erosion. Moreover, this network shows a high degree of incision and narrow interfluves. The second major canyon trends ENE-WSW and is a multi-fed system consisting of three sub-canyons that coalesce at 1095 m water depth. Although tributaries bisect the flanks of this system, they are not mature and have not yet breached the continental shelf, but are mostly confined on the slope. The final canyon is narrower than the previous ones and its thalweg is nearly N-S oriented. Additionally, the flanks of the later differ substantially when it comes to their morphology. The western flank is undulated by linear wall gullies and several landslides indicated by the crescent like rim of high slope values, while the eastern flank is smooth and featureless. Along the SW continental slope, evidence for several old landslide events can be identified. The major failure scars are located right at the edge of the shelf at 560 m water depth.

International audience; Detailed mapping based on the high-resolution grids, such as GEBCO, ETOPO1, GlobSed, EGM-2008 is crucial for various domains of Earth sciences: geophysics, glaciology, Quaternary, sedimentology, geology, environmental science, geomorphology, etc. The study presented a GMTbased scripting technique of the cartographic data processing aimed at the comparative analysis of the bathymetry, sediment thickness, geologic objects and geophysical settings in the study area based on various datasets. The study area is located in the Ross Sea, Antarctic. The highest values of the sediment thickness over 7,500 m are dominating in the southwest segment of the Ross Sea closer to the Victoria Land, followed by the region over the Ross Ice Shelf with values between 5,500 to 7,000 m (170°-175°W). The increased sediment thickness (2,500 to 3,000 m) was also mapped seen in the region NE off the Sulzberger Bay (70-75°S to 140-155°W), caused by the closeness of the Marie Bird Land ice coasts. A remarkable correlation between the gravity and the topography of the sea-land border in the Marie Bird Land area is well reflected in the coastal line and a set of the higher values in the free-air gravity. On the contrary, negative values (-60 to-80 mGal) are notable along the submarine troughs stretching parallel in the western part of the basin: e.g. the trough stretching in NW-SE direction in the 170°W-175°E, 65°S-68°S, between the 167°W-175°W, 70°S-72°S. Such correlations are clearly visible on the map, indicating geological lineaments and bathymetric depressions correlating with gravity grids. The paper contributes to the regional studies of the Ross Sea, the Antarctic and Polar region, and development of the technical cartographic methodologies by presenting an application of the GMT for thematic mapping.; O mapeamento detalhado com base em grades de alta resolução, como GEBCO, ETOPO1, GlobSed, EGM-2008 é fundamental para vários campos das ciências da terra: geofísica, glaciologia, quaternário, sedimentologia, geologia, ciências ambientais, geomorfologia, etc. O estudo apresenta métodos de processamento de dados de mapas com script baseado em GMT visando a análise comparativa de batimetria, espessura de sedimentos, características geológicas e condições geofísicas na área de estudo com base em vários conjuntos de dados. A Área de Estudo está localizada no Mar de Ross, na Antártica. Os valores mais altos de espessura de sedimento de mais de 7.500 m prevalecem no sudoeste do Mar de Ross próximo a Victoria Land, seguido pela área acima da plataforma de gelo de Ross em valores entre 5.500 e 7.000 m (170 ° -175 ° W). ... O aumento da espessura do sedimento (de 2.500 a 3.000 m) também foi mapeado na área nordeste da Baía Sulzberger (de 70-75 ° S a 140-155 ° W), devido à proximidade das costas de gelo da Terra Marie Bird. A notável correlação entre a gravidade e a topografia da fronteira marítima perto da Terra Marie Bird é bem refletida na linha costeira e em muitos dos maiores valores de gravidade ao ar livre. Em contraste, os valores negativos (-60 a -80 mGal) são perceptíveis ao longo das muralhas submarinas que se estendem paralelamente na parte oeste da bacia: por exemplo, uma trincheira que se estende na direção noroeste-sudeste a 170 ° W-175 ° E, 65 ° S-68 ° S, entre 167 ° W-175 ° W, 70 ° S-72 ° S Essas correlações são claramente visíveis no mapa, indicando lineamentos geológicos e depressões batimétricas correlacionadas com grades gravimétricas. O documento contribui para estudos regionais do Mar de Ross, Antártica e região polar, bem como para o desenvolvimento de metodologias técnicas de mapeamento, introduzindo a aplicação GMT para mapeamento temático.

Until the year 2019 only around 15% of the Earth’s seafloor were mapped at fine spatial resolution (

International audience; The paper discusses the geomorphology of the Sunda Trench, an oceanic trench located in the eastern Indian Ocean along the Sumatra and Java Islands of the Indonesian archipelago. It analysis difference in depths and variation in slope steepness between the two segments of the trench: southern Java transect (108.8°E 10.10°S - 113.0°E 10.75°S) and northern Sumatra transect (97.5°E 1.1°S - 101.0°E 5.5°S). The maps and geomorphological modelling were plotted using Generic Mapping Tools (GMT). The data include high-resolution grids on topography, geology, geodesy and geophysics: GEBCO, EGM2008 EGM-2008, GlobSed. The results include modelled segments, slope gradients, and cross-section profiles. The geological processes take place in the Indian Ocean at different stages of its evolution and influence the nature of the submarine geomorphology and geomorphology of the trench that differs in two segments. Java segment has a bell- shaped data distribution in contrast to the Sumatra with bimodal pattern. Java segment has the most repetitive depths at -2,500 to -5,200 m. Sumatra transect has two peaks: 1) a classic bell-shaped peak (-4,500 m to -5,500 m); 2) shelf area (0 to -1,750 m). The data at middle depths (-1,750 to -4,500 m) have less than 300 samples. The most frequent bathymetry for the Sumatra segment corresponds to the -4,750 m to -5,000 m. Comparing to the Sumatra segment, the Java segment is deeper. For depths > -6,000 m, there are only 138 samples for Sumatra while 547 samples for Java. Furthermore, Java segment has a more symmetrical geometric shape while Sumatra segment is asymmetric, one-sided. The Sumatra segment has a steepness of 57.86° on its eastern side (facing Sumatra Island) and a contrasting 14.58° on the western part. The Java segment has a steepness of 64.34° on its northern side (facing Java Island) and 24.95° on the southern part (facing the Indian Ocean). The paper contributes to the studies of the submarine geomorphology in Indonesia.; Резиме: У раду су детаљно анализиране геоморфолошке карактеристике Сундског рова, који се пружа дуж острва Суматра и Јава у оквиру индонежанског архипелага, у источном делу Индијског океана. Познато је да је геоморфологија океанских ровова настала као резултат субдукције тектонских плоча током сложене геолошке еволуције. Упркос покушајима да се детаљно проучи његова геодинамика, природа и структура рова још увек нису довољно јасни. Конкретно, геоморфолошке карактеристике рова, формиране кроз сложене интеракције геофизичких, геолошких и тектонских фактора, у фокусу су многих истраживања. Сврха овог рада је да истражи разлике у геоморфолошким карактеристикама два различита сегмента Сундског рова (јужни део дуж острва Јава и северни део дуж острва Суматра) како би се олакшало боље разумевање структуре морског дна у североисточном делу Индијског океана. Методолошки приступ овог рада заснован је на употреби GMT, односно универзалних картографских инструмената, који су примењени у циљу конструисања графичких прилога. У овом квалитативном и квантитативном истраживању израђено је осам карата и обављен је преглед бројне литературе о истраживаном подручју.Јужни, јавански сегмент рова простире се дуж линије са следећим координа- тама (почетна и крајња тачка): 108,8°Е 10,10°S - 113,0°Е 10,75°S. Северни, суматрански сегмент лоциран је дуж линије са следећим координатама (почетна и крајња тачка) 97,5°Е 1,1°S - 101,0°Е 5,5°S. Подаци укључују растерску координатну мрежу високе резолуције о топографији, геологији, геодезији и геофизици: GEBCO, EGM2008EGM-2008, GlobSed. Представљено је и визуализовано неколико тематских карата са циљем демонстрирања просторне варијације у дистрибуцији геофизичких поља на проучаваном подручју. Карте посебно илуструју геолошке процесе који су се одвијали у источном делу Индијског океана у различитим фазама његове еволуције, а које су утицале на изглед подморске геоморфологије рова. Попречни профили су дигитализовани помоћу приступа машинског учења којег нуди GMT. Упоредна анализа оба сегмента извршена je визуелизацијом података у виду хистограма. Резултати истраживања показују да је геоморфологија рова зависна од локалних геолошких, геофизичких и тектонских карактеристика. Конкретно, јавански сегмент има дистрибуцију дубина у "облику звона", за разлику од суматранског са бимодалном дистрибуцијом. У сегменту Јаве најчешће је распрострањен појас дубина између -2.500 и -5.200 m. Сегмент Суматре има два јасно видљива врха: 1) врх у облику звона (-4.500 m до -5.500 m); 2) подручје шелфа (0 до -1.750 m). У поређењу са сегментом Суматре (северни), сегмент Јаве (јужни) је дубљи. На пример, за дубине преко -6.000 m постоји само 138 узорака за сегмент22Суматре, док постоји 547 узорака за сегмент Јаве. Даље, јавански сегмент има симетричан геометријски облик, док је сегмент Суматре углавном асиметричан. Сегмент Суматре има нагиб од 57,86° на источној страни (страна окренута према острву Суматра) и 14,58° на западној страни. Сегмент Јаве има нагиб од 64,34° на северној страни (страна окренута према острву Јава) и 24,95° у јужном делу (према Индијском океану).Значај картографске визуелизације је добро познат, јер тачно представљање података помаже да се изврши корелација и укаже на разлике у дистрибуцији геолошких и географских објеката, процеса и појава. Најчешће, традиционални GIS софтвери преовлађују у картографским истраживањима. Овај рад указује на ефикасну функционалност софтвера GMT за визуализацију геофизичких и геолошких података и за проучавање геоморфолошких карактеристика. Нејасност и неразумевање геолошких и геодинамичких процеса често проистиче из недостатка картографске визуализације која покрива одређено истраживачко подручје у правилној пројекцији и палети боја. Да би се повећала ефикасност у анализи података, представљене карте конструисане су у три различите пројекције: поликонусној, меркаторовој и азимутној пројекцији Ламберта, док су попречни профили урађени са декартовим xy координатама. Значај овог рада састоји се у мултидисциплинарном приступу који комбинује савремена картографска представ- љања података и геолошку анализу индонежанског региона. Резултати ове студије показују да су коришћење картографских метода за обраду геоинформација драгоцено средство за даља геофизичка и геоморфолошка моделовања и помоћ у бољем разумевању морског дна, јединствене скривене структуре Земљине површи- не.

In this paper the latest versions of six publicly available bathymetry models: DTU10bat, EMODnet 2018, ETOPO1, GEBCO 2020, Smith and Sandwell V20.1 and SRTM15+ V.2.1. are compared and evaluated in the area of continental shelf of Croatia settled along well intended east Adriatic coast. Survey data in the area is not available through open access data bases, but publicly accessible in agreement with data holders (hydrographic institute, research centres and industry). These grids provide alternative sources of information about seafloor topography. Marine researchers should be acquainted with the main characteristics as well as pros and cons of bathymetry models in order to choose the best one for a specific purpose. In this paper the most important characteristics and information about grids are presented: resolution, coverage, release date, horizontal and vertical datum, data source, registration method, producer and link to website with an emphasis on the underlying source data. The underlying source data is one of the most important parameters that determine the quality of the bathymetric model. Hypsometry curve that is describing the area distribution of depth is calculated for each bathymetry model over the test area of the east Adriatic. For pixel to pixel comparison, grids were resampled to same one-minute resolution and absolute differences between models are calculated in identical points. Absolute differences between models show level of mutual compatibility between models as well as areas of highest disagreements that indicate the presence of outliers or systematic errors within models. In order to demonstrate how well publicly available bathymetry models fit the true topography of the sea floor, grids were compared to high-resolution digital bathymetry model interpolated from the multibeam survey in the area of Murter Sea. This paper should assist in the choice of a most suited bathymetry grid in future maritime studies in the Adriatic.

The paper discusses geomorphology of the Sunda Trench, an oceanic trench located in eastern Indian Ocean along the Sumatra and Java Islands of the Indonesian archipelago. In particular, it analysis the difference in depths and variation in slope steepness between the two segments of the trench: the southern Java transect (coordinates 108.8°E 10.10°S to 113.0°E 10.75°S) and the northern Sumatra transect (97.5°E 1.1°S to 101.0°E 5.5°S). The thematic maps and geomorphological modelling were plotted using Generic Mapping Tools (GMT). The materials include high-resolution data on topography, geology and geophysics: GEBCO 15 arc-minute resolution grid, EGM2008 2.5 minute Earth Gravitation Model of 2008, GlobSed global 5‐arc‐minute total sediment thickness and vector geological datasets. In addition to the GEBCO-based bathymetric data, geological, topographic and geophysical maps, the results include enlarged transects for the Java and Sumatra segments, their slope gradients and cross-section profiles, derived from the bathymetric GEBCO dataset. The geomorphology framework of the Sunda Trench is largely controlled by the subduction of the Australian plate underneath the Sunda microplate. The geological processes take place in basin of the Indian Ocean at different stages of its evolution and influence the nature of the submarine geomorphology and geometric shape of the trench. Sunda Trench is seismically active part of the Pacific Ring of Fire. A large number of the catastrophic earthquakes are recorded around the trench. The histograms shows variation in depths along the segments of the Sumatra and Java. The Java segment has a bell-shaped data distribution in contrast to the Sumatra with bimodal pattern. The Java segment has the most repetitive depths at -2,500 to -5,200 m. The Sumatra transect has two peaks: 1) a classic bell-shaped peak at depths -4,500 m to -5,500 m; 2) shelf area with a peak from 0 to -1,750 m. The data at middle depths (-1,750 to -4,500 m) have a frequency -6,000 m, there are only 138 samples for the Sumatra while 547 samples for Java. Furthermore, Java segment has more symmetrical geometric shape while Sumatra segment is asymmetric, one-sided. The Sumatra segment has a steepness of 57.86° on its eastern side (facing Sumatra Island) and a contrasting 14.58° on the western part. The Java segment has a steepness of 64.34° on its northern side (facing Java Island) and 24.95° on the southern part (facing Indian Ocean). The paper contributes to the studies of the submarine geomorphology in Indonesia.

This research focuses on the 2D and 3D geospatial analysis of the Ryukyu Trench, a deep-sea trench located in the western Pacific Ocean between Japan and Taiwan. The aim of the research is to visualize regional differences in the topography of the southern (S) and northern (N) parts of the trench. Technically, the methodology is based on using the Generic Mapping Tools (GMT) scripting toolset, for modelling the General Bathymetric Chart of the Oceans (GEBCO), and Earth Topography and Bathymetry dataset (ETOPO1) raster grids. The results demonstrated topographic differences in the two segments. The most frequent depths lie between −5,000 and −6,000 m. The N part has steeper gradient slopes and deeper bathymetry. Of the depth differences >−6,000 m, S has nine values with depths >−6,800 m while N shows 123 records (max −7,460 m). The submarine terraces of S have gentler slopes compared with the N segment. The technical approach presents GMT-based 2D and 3D cartographic modelling aimed at visualizing regional variations of the seafloor topography.

This article analyzes topographical and geological settings in the Japan Archipelago for comparative raster data processing using GRASS GIS. Data include bathymetric and geological grids in NetCDF format: GEBCO, EMAG2, GlobSed, marine free‐air gravity anomaly and EGM96. Data were imported to GRASS by gdalwarp utility of GDAL and projected via PROJ library. Method‐ ology includes data processing (projecting and import), mapping and spatial analysis. Visualization was done by shell scripting using a sequence of GRASS modules: ‘d.shade’ for relief mapping, ‘r.slope.aspect’; for modelling based on DEM, ‘r.contour’ for plotting isolines, ‘r.mapcalc’ for classification, ‘r.category’ for associating labels, and auxiliary modules (d.vect, d.rast, d.grid, d.legend). The results of the geophysical visualization show that marine free‐air gravitational anomalies vary in the Sea of Japan (–30 to above 40 mGal) reflecting density inhomogeneities of the tectonic structure, and correlating with the geo‐ logical structure of the seafloor. Dominating values of geoid model are 30–45 m reflecting West Pacific rise, determined by deep density inhomogeneities associated with the mantle convention. Sediment thickness varies across the sea reflecting its geological development with density of 2 km in its deepest part and thinner in central part (Yamato Rise). The aspect map and reclassified map express gradient of the steepest descent.

The study investigated geomorphology of the Japan Trench located east of Japan, Pacific Ocean. A high-resolution GEBCO Gridded Bathymetric Dataset was used for modeling, mapping and visualization. The study aimed to compare and analyse variations in the geomorphic structures of the two parts of the trench and to visualize variations in the geological, geophysical and bathymetric settings. Technically, the cartographic work was performed using scripting based on the Generic Mapping Toolset (GMT). Modelled cross-sectioning orthogonal profiles transecting the trench in a perpendicular direction were automatically digitized and graphed in the two segments. The results of the bathymetric analysis shown that the southern part is shallower: with deeper values in absolute (139 samples between –7000 to –8000 m) and statistical records (the most frequent values are within –5500 to –5800 m) comparing to the northern segment (–5300 to –5500 m). The geomorphological analysis shows a more complicated relief in the northern part of the trench, which has a higher seismic activity. The southern part has a gentler slope on the Honshu island side. The geoid modeling along the trench ranges in 0–20 mGal. The highest values are recorded by the Honshu Island (>40 mGal). The rest of the area has rather moderate undulations (20–40 mGal). The free-air marine gravity of the Sea of Japan is

Tsunami occurred on June 3, 1994, as a result of the earthquake in Banyuwangi at 10,477° South Latitude and 112,835° East Longitude with magnitude 7.2 SR. Tsunami in Banyuwangi causes 122 victims, 15 missing persons, 450 houses completely ruined, over 250 heavily damaged in Pancer village and 6 fishermen disappear. In 2006, The Pangandaran Tsunami also attacked coastal area in South Java. This study aims to model tsunami in Puger Beach using Delft3D with the combination of earthquake source characteristics in South Java. Bathymetry data and topography were taken from The General Bathymetric Chart of the Oceans (GEBCO). Delft3D Dashboard was utilized as a first step to create a model domain and simulation grid. Bathymetric interpolation to the simulation grid and initial surface elevation were also created from earthquake fault parameters using Delft3D Dashboard. After setting parameters, numerical simulation was carried out using Delft3D-FLOW. To conduct model validation, the data observation of the 1994 Banyuwangi tsunami from the previous research was utilized. The locations used for validation in this study were Cape Pelindu, Puger and Watu Ulo Beaches with the maximum water level 3.2 m, 4.88 m - 5.85 m and 6.5 m - 7.5 m, respectively. Simulations were divided into three scenarios. Scenario 1 was a simulation of the 1994 Banyuwangi tsunami. Scenario 2 was a simulation to represent the characteristic of fault from The 2006 Pangandaran Earthquake in Puger Beach. Scenario 3 was a combination between Scenario 1 and Scenario 2 which represented tectonic plate fault simulation. Based on the results of the simulation 3, the time of maximum tsunami height reached the study area at the 40 minutes and back to normal at 170 minutes. The greatest impact was created from Scenario 3 with tsunami heights of 10.91 meters to 22.34 meters.

Summary On a base of the updated version of GEBCO bathymetric data (2020) for the Mississippi Delta and the Azov-Black Sea basin, cartographic schemes of the bottom tilt angles were constructed. Based on the results of landslide threats studies in the World Ocean, a significant risk has been established for the functioning of oil and gas platforms and subsea pipelines even at small bottom angles of 0.5–1°, especially high in areas of low consolidation of bottom sediments. It is recommended to conduct landslide hazard studies in the offshore areas of other Russian seas with first priority of the Arctic shelf, where the existence of submarine permafrost zone and gas hydrates increases the risk of landslide processes.

International audience; The papers presents an integrated processing of the high-resolution thematic data covering the area of the Beaufort Sea, a marginal sea of the Arctic Ocean, northern Canada and Alaska. Five thematic maps of the Beaufort Sea, Arctic Ocean are presented. The cartographic techniques were performed by Generic Mapping Tools (GMT) scripting toolset. The methodology presents the integration of the multi-source high-resolution thematic datasets: bathymetric GEBCO, IBCAO, topographic GLOBE, sediment thickness GlobSed, EGM2008 geoid model, GMT vector layers and geophysical gravity model from CryoSat-2 and Jason-1. There is an agreement with the data by their inspection and analysis of grids correlation. The bathymetric map demonstrated variations in depths with rapidly decreasing values in the Mackenzie River coasts, depicting the basin of the Beaufort Sea, large shelf in the Canadian Arctic Archipelago and western part bordering the Chukchi Sea. The GDAL inspection shows that the GEBCO-based topography ranges between -3,973 m to 2,578 m. Gravity data shows that coastal areas in northern Canada and Alaska have values >20 mGal while the basin of the Beaufort Sea is dominated by the lower values at -65 to -45 mGal; the data range is from -155.097 to 366.939 mGal. The marine free-air gravity fields and geoid data demonstrate correlation with topographic isolines of the region. The data range for the sediment thickness is from 0.00 to 18064.53 m having maximal data at the Mackenzie River discharge area. A comprehensive compilation of the data on the Beaufort Sea visualized using GMT presents more insights into its bathymetric structure and geophysical fields distribution in context of the variability of the geological settings.

This study aims to determine oceanographic characteristics such as tides, waves, and currents in Karimunjawa Coastal Waters [wp1] during the 1st transitional season and to update the oceanographic data [wp2] base for spatial management evaluation in the region. The tidal characteristics were obtained from the least square method analysis using World Tide software based on Matlab programming language, while wave and current characteristics obtained from 2-dimensional numerical modeling using Mike 21 software on the flow model and spectral wave module. The primary data used were the significant wave height (Hs), wave peak period (Tp), and ocean current components (u and v velocity) on 13-26 May 2016 using the Sontex Argonaut XR type Acoustic Doppler Current Profiler (ADCP) equipment. Tide data were predicted for the Kemujan Islands station from 1-31 March 2020. Secondary data for additional numerical model input were obtained from ERA5-reanalysis in the form of Hs, Tp, u, and v wind velocity data for May 2020 with a temporal resolution of 20 minutes, while bathymetry data derived from GEBCO Satellite Derivated Bathymetry (SDB) data. The tide analysis results showed that Karimunjawa waters are a single daily mixed tidal type. The wave characteristic moves from east to west with high waves reached 0.9 meters and a peak period of 7 seconds. [wp3] The eastern side of Karimunjawa Island, Kemujan Island, and the western area have a calmer wave. The current characteristic moves northeastward with a speed of 5-28 cm/s, which concludes that in several locations, such as the Menjangan Besar-Menjangan Kecil strait, the currents depend on the tidal conditions.

In this paper, we investigate the wave attenuation by mangroves using modified 2D Nonlinear Shallow Water Equations. Numerically, we solve the model using a staggered finite volume method that is free from damping error. Further, several benchmark tests are performed to show the robustness of our numerical model. Then, we implement our numerical model to investigate the effects of mangroves in the wave attenuation caused by tsunamis in Manila Bay. The bathymetry profile of Manila Bay used in this study is obtained from the General Bathymetric Chart of the Oceans (GEBCO). Numerical results show that the presence of mangroves can reduce ocean waves near the coast. Simulations on varying density and width of mangrove forest quantify how much the tsunami wave height can be reduced. The results of this work may guide the policymakers of the Philippines in deciding the best strategy in rehabilitating Manila Bay.

The effect of the quality of bathymetric data on the accuracy of tsunami-wave field calculation is considered. A review of the history of the numerical tsunami modeling development is presented. Particular emphasis is made on the World Ocean bottom models. It is shown that the modern digital bathymetry maps, for example, GEBCO, do not adequately simulate the sea bottom in numerical models of wave propagation, leading to considerable errors in estimating the maximum tsunami run-ups on the coast.

Sadai strait is located in between of Bangka and Lepar island (Pulo Lepa). Gaspar strait positioned between Bangka and Belitung island was named after the Spanish captain passed through it from Manilla in 1724. Southeast part of Bangka had been called Macclesfield after Captain Hurle in English ship Macclesfield. The myth of many pirates, the legend of many sunken of warship and merchant ships of Chinese, Dutch, Japanese at Gaspar Strait. The southernmost dangered Fairlie Rock was named and discovered by a merchant company ship Fairlie in 1813 and a more detail examination by Captain Ross at surveying ship Discovery in 1814. A Portuguese ship sail from Macao was wrecked in 1816 at Discovery Rock. The study aims to build and analyze the bathymetric, current spatial model and tide data to discover the oceanographic characters related to the sunken ships legends. Measurement based on a hydroacoustic method using single beam echosounder for primary data, GEBCO bathymetric and Landsat-8 satellite for secondary data. GPS coordinate and depth value of x-y-z was processed for a spatial layer using geo-statistical gridding method. A spatial numerical model of current based on data of bathymetry and tide data using the hydrodynamic module to build two and three-dimensional models based on a triangular mesh (system flexible mesh) spatial unit with consideration on the seawater baroclinic condition. Narrow strait and small islands widely distributed around Gaspar strait as a channel of no escape in the case of sailboat piracy. Oceanographic variable mainly caused by extremity and known as the most dangerous ‘Fairli-and Discovery rock’ with narrow and shallow rock bottom morphology especially at low tides and considerable extent of sand-dunes and the north (Natuna island) to south (Bangka-Belitung) seawater volume transport and current pattern interactions seems to be the most dominant and unpredictable situations for ship line safety.

Present tectonic activities around the Andaman–Sumatran subduction zone gives an alarming signal of a possibility of occurring tsunamis in the Indian Ocean again and could bring devastation for rim countries in the Indian Ocean. Hence, proper understanding about possible tsunami inundation levels is a prerequisite for disaster prevention and management processes in tsunami prone areas such as low elevation coastal areas in the eastern coast of Sri Lanka. Therefore, as an initial step, present study was carried out to simulate tsunami propagation and inundation for Kallady city in the eastern coast of Sri Lanka to understand about vulnerable areas for future tsunamis. Kallady is a low lying, populated coastal city in eastern province of Sri Lanka. In this study, tsunami wave propagation and inundation in Kallady area under different scenarios namely, 2004 tsunami event and two hypothetical tsunamis with magnitudes of 9.5 and 10.5 respectively, where the epicenter of the earthquake of hypothetical two tsunamis was assumed to be similar to the 2004 tsunami event. Tsunami wave propagation and successive land area inundation were simulated using ELIMO and Nays2DFlood solvers of iRIC interface accordingly. Bathymetric and topography data were obtained from GEBCO, SRTM and recent field investigations in 2017. Initial sea surface elevations were simulated using Okada’s formula. ELIMO resolves well the wave propagation. However, Nays2D Flood determines inundation level significantly lower since it only employs water level record to model the inundation.

We present research using single-image super-resolution (SISR) algorithms to enhance knowledge of the seafloor using the 1-minute GEBCO 2014 grid when 100m grids from high-resolution sonar systems are available for training. We performed numerical experiments of x15 upscaling along three midocean ridge areas in the Eastern Pacific Ocean. We show that four SISR algorithms can enhance this low-resolution knowledge of bathymetry versus bicubic or Splines-In-Tension algorithms through upscaling under these conditions: 1) rough topography is present in both training and testing areas and 2) the range of depths and features in the training area contains the range of depths in the enhancement area. We quantitatively judged successful SISR enhancement versus bicubic interpolation when Student's hypothesis testing show significant improvement of the root-mean squared error (RMSE) between upscaled bathymetry and 100m gridded ground-truth bathymetry at p < 0.05. In addition, we found evidence that random forest based SISR methods may provide more robust enhancements versus non-forest based SISR algorithms., Computer Science; Earth sciences; single-image super-resolution; upscaling; bathymetry

Detailed knowledge of the shape of the seafloor is crucial to humankind. Bathymetry data is critical for safety of navigation and is used for many other applications. In an era of ongoing environmental degradation worldwide, bathymetry data (and the knowledge derived from it) play a pivotal role in using and managing the world’s oceans in a way that is in accordance with the United Nations Sustainable Development Goal 14 - conserve and sustainably use the oceans, seas and marine resources for sustainable development. However, the vast majority of our oceans is still virtually unmapped, unobserved, and unexplored. Only a small fraction of the seafloor has been systematically mapped by direct measurement. The remaining bathymetry is predicted from satellite altimeter data, providing only an approximate estimation of the shape of the seafloor. Several global and regional initiatives are underway to change this situation. This paper presents a selection of these initiatives as best practice examples for bathymetry data collection, compilation and open data sharing as well as the Nippon Foundation-GEBCO (The General Bathymetric Chart of the Oceans) Seabed 2030 Project that complements and leverages these initiatives and promotes international collaboration and partnership. Several non-traditional data collection opportunities are looked at that are currently gaining momentum as well as new and innovative technologies that can increase the efficiency of collecting bathymetric data. Finally, recommendations are given towards a possible way forward into the future of seafloor mapping and towards achieving the goal of a truly global ocean bathymetry.

The GEBCO-NF Alumni Team is one of the five teams who completed the final round of the Shell Ocean Discovery XPRIZE challenge. This international team is made up of industry experts, advisors from within the GEBCO community and broader ocean community and is led by alumni from the Nippon Foundation / GEBCO Graduate Certificate Ocean Mapping Training Program at the Centre for Coastal and Ocean Mapping / Joint Hydrographic Center (CCOM/JHC) of the University of New Hampshire. The Team is distinguished by its extraordinary diversity with a global distribution of representatives from academic institutions, offshore survey and technology industries, academia as well as national hydrographic offices. The alumni worked closely with partners such as Hushcraft Ltd., Ocean Floor Geophysics Inc., Earth Analytic and Teledyne CARIS as well as equipment supplier Kongsberg Maritime AS to develop and advance the Team concept created for the Shell Ocean Discovery XPRIZE. The project was established and supervised at the University of New Hampshire.The Shell Ocean Discovery XPRIZE competition aimed to push the boundaries of ocean technologies by creating solutions to the grand challenge of mapping our ocean floor. The competition requirements had to be met within a short timeline of approximately one year per round. The Round 2 final field test was to demonstrate a complete system that could map 250 km2 in 24 hours to produce a grid with 5 m cell size and at least 10 images of the sea floor. Operations had to be remotely coordinated from a land-based operation center. The entire mapping system had to fit into a standard 40-foot shipping container.The aim of the GEBCO-NF Alumni Team has been to leverage existing technology, wherever possible, and to integrate them to achieve the competition requirements. The strategic approach is to develop strong partnerships with technology and services providers to augment the hardware, integration and software needs of the Team.The GEBCO-NF Alumni Team conceived a two-system, Autonomous Underwater Vehicle (AUV) and Remote-controlled or Unmanned Surface Vehicle (USV), concept to autonomously map the seafloor in a wide variety of ocean environments. Autonomous seafloor surveys, with remote AUV launch and recovery (human-in-the-loop) and with the USV autonomously tracking the AUV for a complete survey mission while being monitored from a remote shore station, were demonstrated to be a viable option for future offshore survey and inspection projects during Round 1.SEA-KIT, the Team’s USV, is an innovative new vessel that allows for autonomous management of AUV deployment and retrieval. In addition, the capability of being a stand-alone mapping platform was demonstrated during the competition using Kongsberg Maritime’s deep-water multibeam sonar EM304 mounted on the gondola below SEA-KIT.The Kongsberg Maritime HUGIN AUV was used for this competition to execute the underwater operations. The Team was confident that competition criteria could be met by overcoming the surface challenges of delivering an AUV to a deep-water location for mapping, coupled to the proven abilities of the HUGIN.During Round 2 Field Test, the team demonstrated automated and remote processing using a cloud-based hosting environment. End users (judges) were able to consume the GEBCO-NF Alumni Team information rapidly and efficiently.The technology, processes and procedures developed for this project are a big step towards larger scale implementation of these concepts. This development of new and innovative technologies that increase the efficiency of seafloor mapping is the Team’s contribution towards helping meet the ambitious goals of the Nippon Foundation—GEBCO Seabed 2030 Project.

Tropical cyclone Cempaka entered South Java sea from 25th November 2017 until 27th November 2017 and caused strong winds and high waves. Delft 3D Modeling Simulation was used to investigate the effect of tropical cyclone Cempaka development on sea level rise in coastal areas and high waves in the South Java sea. The FNL wind data with a resolution of 0.25° × 0.25 ° and GEBCO bathymetry data with a grid resolution of 30 seconds was used as input to the Delft 3D model. The results of the study showed that there was an increase of significant wave height during the tropical cyclone Cempaka period with significant wave values from 1 to 3.5 meters on 27th November 2017. While for the value of sea level height in the coastal area showed results there was an increase during cyclone Cempaka period with anomalies values to 0.4. However, at the center of the cyclone had a low anomaly value that reached -0.2. From the results of the correlation test and RMSE test on sea level Delft 3D output obtained a correlation value of 0.85 and error 0.43 in the Sadeng, Yogyakarta. while the correlation test and RMSE test for the significant wave height parameter obtained a correlation value -0.198 and error value 0.168.

An understanding of ocean bathymetry is important in marine planning, navigation, military activities, and environmental monitoring. The fusion of spatial data, such as those from multi-source digital bathymetric models (DBMs), can effectively improve the efficiency of large-scale seafloor topographical research and the accuracy of the results obtained therein. On the one hand, with the release of 15arc-seconds resolution DBMs, it is now necessary to verify the quality of these new products. On the other hand, in order to generate a new, high-quality, seamless DBM in the South China Sea (SCS) and adjacent areas, an adaptive subregional spatial-domain-weighted fusion framework is proposed. First, seven of the most widely used global DBMs are selected, and multi-source subregional measured depth-sounding data undergo data cleaning and other preprocessing. Next, based on the homogeneity of the terrain features, an adaptive subregional topographical analysis is performed, and the subregional data are weight-fused. Finally, the fusion dataset is post-processed via model smoothing and other procedures. In addition, the advantages and limitations of the DBMs of the SCS are compared. The results show that SRTM15_PLUS V2 is the most reliable of the original DBMs. The updated seamless SCS DBM is void-free and more similar to SRTM15_PLUS V2 with a resolution of 15arc-seconds. The root mean square error (RMSE) of the new model is 99.60 m. Its accuracy is 13%, 40%, 15%, and 1% higher than those achieved by the GEBCO_2019, GEBCO_2014, SRTM30_PLUS, and SRTM15_PLUS models, respectively, and its expression of the topography is more detailed and realistic. The feasibility and limitations of the proposed fusion framework are demonstrated. The present findings provide a useful reference for the timely reconstruction and updating of large-scale seafloor topography from multiple datasets.

The coastal wave dynamics of Agatti island situated on a coral atoll in Lakshadweep, India, having a notable topographic feature of steeper eastern shore over the western shore, is analysed in this study. A multinested model setup is generated using the global third-generation models WAM (Wave Modeling) and SWAN (Simulating Waves Nearshore). A high resolution unstructured grid is generated for the domain containing the island using SMS (Surface-Water Modeling System) interpolated with merged GEBCO (General Bathymetric Chart of the Oceans) and SRTM (Shuttle Radar Topography Mission) bathymetry. The SWAN model is integrated with a fine resolution of one minute by one minute during the tropical storm 01A (05–10 June 2004) which passed near the island. Model simulated significant wave height data when validated against satellite observations exhibited high accuracy. SWH (significant wave height) is observed to be greater for the west coast than that over the east coast of the island due to steeper eastern shore and there is widespread wave energy dissipation along the southwest direction of wave propagation during normal conditions. The one-dimensional energy density spectra generated during the storm period exhibit multimodality with structured and unstructured grids.

The study aims is to define bathymetry based on General Bathymetric Chart of the Oceans (GEBCO) and Nautical Map using GIS technique. The methods used in this study are the kriging method which combines the spatial correlation among the data using GIS and Remote Sensing software. The result shows that bathymetry at research area can be divided into five classes, these are: (1) 0-2 meter with area of 1.797,61 hectare, (2) 2-5 meter with area of 2.059,06 hectare, (3) 5-10 meter with area of 1.184,02 hectare, (4) 10-25 meter with area of 3.025.00 hectare, (5) 25-200 meter with area of 5.648.62 hectare.The spatial pattern of bathymetry dispersed from the shallow water at the edge of beach and more deep at the offshore, except at the eastern side of Wangi-Wangi island which has barrier reef and created basin between them.

In this paper, we report on a preliminary investigation into a semi-empirical method for derivation of depth–age relationship for oceanic lithosphere. The global 30-arcsecond bathymetry data from the General Bathymetric Charts of the Oceans (GEBCO) were corrected for (1) sediment thickness using the Total Sediment Thickness of the World’s Oceans and Marginal Seas and (2) isostasy. The corrected bathymetry was processed to obtain the empirical bathymetric curve, the solution computed with 50 m elevation bin. Subsequently, the data-based curve was approximated with the optimal polynomial model. By combining the model with a formula for derivative of area with respect to age, we obtained the approximate differential equation for depth–age relationship. We solved the equation numerically. The solution was compared with (1) depth–age relationships derived empirically using the combination of the corrected GEBCO bathymetry with digital isochrons of the oceans, (2) Parsons Sclater Model (PSM) and (3) Global Depth Heatflow model (GDH1). In the new depth–age curve, three sections with specific relationships of ocean depth versus age of the crust are identified: (1) moderate increase in depth from 2500 to 5900 m for lithospheric ages 0–118 Ma, (2) more pronounced increase in depth from 5900 to 6700 m for the lithosphere 118–147 Ma old, (3) stabilization of ocean depth at 6700–6760 m for the lithosphere older than 147 Ma. The fit to empirical data as well as PSM and GDH1 models is good for the first section, but rather imperfect for the other two. Reasons for mismatches are complex and probably different for dissimilar sections of the curve.

Long period magnetotelluric (LMT) data are generally used as the prime tool to shed light on the conductivity of the deep crust and upper mantle structure. Naturally, LMT data are sensitive to the influence of highly conductive bodies even at far distances. Sea water constitutes the main widespread electrical conductor at shallow levels of the Earth's crust. Its low resistivity values, around 0.25 Ωm, contrast sharply with most geological structures of solid earth. Consequently, the presence of irregular continental borders and varying bathymetries significantly influences LMT parameter, such as phase tensor and tipper vectors. This effect is especially important in areas where large and small oceans are connected by narrow gateways. The Gibraltar Strait (southern Spain) connects the vast Atlantic Ocean with the irregular and relatively small Mediterranean Sea. Several 3D models have been developed in the region nearby the Strait, some featuring a roughly simplified geological structure, to show the influence of seawater on tipper and phase tensor. Here, detailed bathymetry (General Bathymetric Chart of the Oceans, GEBCO) including the coastline is considered in a model that enables us to analyze the influence of the Strait of Gibraltar on LMT data. We stress the significance of the Sea for LMT data interpretation and the development of 3D conductivity models, especially in regions involving complex coastline geometries and bathymetry near narrow straits. Forward modeling studies are essential to accurately appraise the sea influence, which may mask 3D geological structures.