Variations in the bathymetry and bottom morphology of the Izu-Bonin Trench modelled by GMT

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, statisti- cal analysis and graphical plotting.