SlopeWeightedEccent​ricity.m

A geomorphometric algorithm to obtain the numerical description of both magmatic and tectonic crust in slow-spreading ridges.

SlopeWeightedEccentricity

(c) Gabriella Alodia — 2021

SlopeWeightedEccentricity.m is a Matlab-based geomorphometric algorithm to obtain the numerical description of both magmatic and tectonic crust in a slow-spreading ridge through a series of calculation based on the distribution of the azimuth and plunge observed in the seafloor morphology.

Input

1. A gridded shipborne multibeam bathymetry (depths in metres) in *.xyz format (here: 'Input_Bathymetry_15s.xyz')
2. A Laplacian-of-Gaussian (LoG) mask created from the bathymetry using a third party software/tool in *.xyz format (here: 'Input_LoG_mask.xyz')

If the LoG mask is not going to be used, we suggest creating a grid with the size and region of the gridded shipborne multibeam bathymetry and assigning the number '1' to all the cells (a 'no mask' example named 'Input_no_mask.xyz' is provided) OR by exempting all the lines with the associated 'mask' from this script.

Output

1. Terrain eccentricity (here: 'Output_eccentricity.xyz')
2. Weight matrix: 1-sin(slope) (here: 'Output_weight.xyz')
3. SWE: Slope-weighted eccentricity (here: 'Output_SWE.xyz')
4. Masked SWE (here: 'Output_SWE_masked.xyz')

Each output is exported in *.xyz format. The resulting *.xyz data can be converted into *.grd using the xyz2grd function in GMT (http://gmt.soest.hawaii.edu/doc/5.3.2/xyz2grd.html)

The shipborne multibeam bathymetry data sample is downloaded from the GMRT MapTool (https://www.gmrt.org/GMRTMapTool/) with the extent xmin/xmax/ymin/ymax of -46/-44/12.5/13.15

Preprint Citation:

Alodia, G., Green, C., McCaig, A., & Paton, D. (2020). Slope-Weighted Eccentricity: Automatic Terrain Classification of Atlantic Ocean Crust. ESSOAr: Earth and Space Science Open Archive. [https://doi.org/10.1002/essoar.10502634.1]

EGU Presentation:

Alodia, G., Green, C., McCaig, A., & Paton, D. (2020). A novel approach for oceanic spreading terrain classification at the Mid-Atlantic Ridge using Eigenvalues of high-resolution bathymetry. In EGU General Assembly Conference Abstracts (p. 337). [https://presentations.copernicus.org/EGU2020/EGU2020-337_presentation.pdf]

Full paper currently in preparation.