Subduction zones are home to the most seismically active faults on the planet. The shallow megathrust interface of subduction zones host our largest earthquakes, and are the only faults capable of M9+ ruptures. Despite these facts, our knowledge of subduction zone geometry - which likely plays a key role in determining the spatial extent and ultimately the size of subduction zone earthquakes - is incomplete. Here we calculate the three- dimensional geometries of all active global subduction zones. The resulting model - Slab2 - provides for the first time a comprehensive geometrical analysis of all known slabs in unprecedented detail.
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This distribution includes models of three-dimensional slab geometry under the banner of the U.S. Geological Survey Slab2 project.
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Please refer to the paper: "Slab2 - A Comprehensive Subduction Zone Geometry Model", by Hayes, G.P., et al., submitted to Science, March 2018.
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Description of Files:
1) *slab2_dep*.grd = NetCDF formatted grid file of slab depth
2) *slab2_str*.grd = NetCDF formatted grid file of slab strike
3) *slab2_dip*.grd = NetCDF formatted grid file of slab dip
4) *slab2_thk*.grd = NetCDF formatted grid file of slab thickness
5) *slab2_unc*.grd = NetCDF formatted grid file of slab depth uncertainty
All grid files can be plotted with with GMT grdimage (http://gmt.soest.hawaii.edu/)
For information on the grid, use:
>gmt grdinfo sum_slab1.0_clip.grd
All supplied models are sampled every 0.05 degrees in both the X (longitude) and Y (latitude) directions.
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Clipping Masks:
Labeled *clp*.csv describe comma-delimited files of the clipping mask (polygon) for each slab model. Outside of the polygon described by the clipping mask, slab models should not be used. Slab node values outside of the clipping mask are equal to NaN.
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Supplementary Files:
Labeled *sup*.csv. Four slab models (Izu-Bonin - izu; Kermadec - ker; Manila - man; and Solomon Islands - sol) include areas where the slab overturns (dip>90ยบ) with depth. In such instances, the slab cannot be described by a continuous surface, and is instead provided as a series of discrete (lon,lat,depth,strike,dip,dz1,dz2,dz3,thickness) nodes, where dz1-3 describe various measures of uncertainty (dz1 corresponds to the PDF standard deviation uncertainty used for unc grids, above; dz2 = interpolated shift magnitude uncertainty; dz3 = smoothing-related uncertainty).
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Contour Files:
Labeled *contours.in. Contours for depth, strike, and dip, generated from the grid files described above.
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Text Files:
Labeled *.xyz. Text files corresponding to each of the grids described above.
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Perl script "slabquery.pl" uses GMT to query slab database for slab, and geomertical parameters (depth, strike, dip, thickness, uncertainty). Script takes {lon, lat} location at command line.
