GMT Based Comparative Geomorphological Analysis of the Vityaz and Vanuatu Trenches, Fiji Basin

Overview & Synopsis

The study is geographically focused on the two deep-sea trenches: Vanu-atu and Vityaz, Fiji Basin, East Australia, located in the area of the double conver-gent complex boundary of Pacific and Indo-Australian plates in the North Fiji back-arc basin. Complex geophysical settings results in the formation of the trenches, seismicity, geodynamic complexity and instability of the region. The work aimed at modelling and comparative statistical analysis of the bathymetry and geomorphology of two trenches. Technically, the methodology of this work is based on the Generic Mapping Tools (GMT) using cartographic mapping of the geophysical, tectonic and geological settings, 2D and 3D modelling, visualizing raster grids GEBCO, ETOPO1, ETOPO5. Histogram topographic equalization (equalized, normalized, quadratic) was done using module 'grdhisteq'. Modelling geoid and gravity was based on EGM96 by sequence of GMT modules. The cross-spectrals of 2D binary raster grids were compared and their coherency plotted by 'grdfft'. The automated cross-sectioning was done using 'grdtrack' module. The results include modelled transects visualizing trenches asymmetry, bathymetric and geomorphic variations. Vityaz Trench is shallower with depths