This programme calculates the displacement due to a propagating dislocation in an elastic half space. StrikeSlipDef then creates cells from this finely discritizes fault trace assigning a width to the slipping surface that is user defined as is the depth. The code then calculates the surface displacment at given location using Okada(1992) subroutine for each cell. Note: the contributions from each event are not summed together, this is done later in the post-processing step. StrikeSlipDef reads in an input file and produces outputs 3 files which are detailed below. StrikeSlipDef can be found and compiled in the src folder using the makefile.
StrikeSlipDef makes the following assumptions:
- Deformation due to dislocation is purely elastic
- Fault dip is vertical and follows surface trace
- Slip of 1m assumed for both shear and tensile dislocation
- Site of interest is near the longitude 27 Degrees (UTM zone 35)
Conventions: x : horizontal displacement (positive in east direction) y : horizontal displacement (positive in north direction) z : vertical displacement (positive in up direction)
Input file for StrikeSlipDef entitled 'input_file.txt' in this the input parameters are:
depth : Depth to top of slipping cells Unit : meter
rake : Orientation of shear dislocation Standard convention applied (i.e.right lateral slip = 180d). Unit= Degrees
slipping_width : width of slipping zone Unit: meters
fault_file : name of file containing discritized fault trace Case provided is Marmara fault based on Şengör et al. (2014) discretization
tekr_lon, tekr_lat: location where surface displacement is calculated. Unit: Degrees
Three files are produced by StrikeSlipDef, all filenames contain the depth of the source in place of the asterisk :
obs_tekr_*.dat : contains the surface displacement at position pzn_lon,pzn_lat due to 1m shear dislocation at each source. Format is as follows : line 1 : number of sources line 2 : number of observation points line 3 : spacing between observation points line 4 : lon , lat line 5 : displacement in x direction (values along the line represent the displacement due to different sources ) line 6 : displacement in y direction (values along the line represent the displacement due to different sources ) line 7 : displacement in z direction (values along the line represent the displacement due to different sources )
obs_tekr_ten_*.dat :same format as obs_tekr_*.dat but displacement is due to tensile dislocations
fault_latlon.txt: file containing geographical coordinates of the corners for each source cell. Each line is a source, with the first position being the top left (west) and proceeding clockwise, the final value is the strike of the cell:
long1, lat1, depth1, long2, lat2, depth2, long3, lat3, depth3, long4, lat4, depth4, strike
Matlab script plot_results.m reads output from StrikeSlipDef and produces figures
Şengör, A. M. C. et al. The geometry of the North Anatolian transform fault in the Sea of Marmara and its temporal evolution: implications for the development of intracontinental transform faults. Canadian Journal of Earth Sciences 51, 222-242 (2014)
Okada, Y., 1992, Internal deformation due to shear and tensile faults in a half-space, Bull. Seism. Soc. Am., 82, 1018-1040.
Georef source code: https://github.com/andherit/georef, doi : 10.5281/zenodo.840875